FI104057B - Recyclable fiber structure and method for its manufacture - Google Patents

Description

104057

Recyclable fiber structure and method for its manufacture

The present invention relates to a fiber structure according to the preamble of claim 1, in particular for packaging and insulating material solutions.

Such a structure generally comprises superimposed layers of fiber which have been treated with an adhesive and cured to form a three-dimensional corrugated fibrous structure.

10

The invention also relates to a method for manufacturing a fibrous structure according to the preamble of claim 10.

The honeycomb structure is widely used in structures requiring lightness, stiffness and 15 high compressive strengths. However, the production of Honeycomb-structured material is a relatively slow and expensive process. Conventionally, it is formed such that a plurality of planar layers of fibrous material fastened superposed at intervals glue sites, which sites are disposed such that the second layer is offset by half the length of the cell layers in the longitudinal direction. Thereafter, the structure is opened by pulling the bottom and top layers outward in opposite directions until adjacent layers of fiber separate and form a honeycomb. The cell structure is hardened by spraying the hardener on it and allowing it to dry.

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Solutions for the production of cured honeycomb structures from sheet-like preforms are also known. Thus, DE-A-3,104,022 discloses a method of stacking corrugated plates and planar plates to form a parallelepiped-shaped body which is cured, after which 9 'slices of suitable size can be cut. A similar solution has been proposed. In EP-A-0 296 604, these known methods, as well as the basic solutions of the honeycomb structures described above, use water-insoluble cross-linking resins as the adhesive. For this reason, known products are not suitable for recycling and the methods disclosed do not provide an alternative for continuous manufacture of the products.

2 104057

The object of the present invention is to eliminate the drawbacks of the prior art and to provide a completely new type of recyclable fiber structure which can be used e.g. in door, furniture, shipbuilding, container bearing and insulating structures and for replacing foam products in packaging and construction and glass. mineral wool products as insulating material.

The invention is based on the idea that the fibrous structure can be recycled if cardboard or similar lignocellulosic material is used as the fibrous material and when water-soluble adhesive is used as the adhesive and the hardener of the structure which, once cured, is redissolved in water. Such adhesives include, for example, water glass (sodium silicate) and sodium carboxymethyl cellulose (Na-CMC) and the like non-crosslinking adhesives.

More specifically, the fiber structure according to the invention is essentially characterized by what is stated in the characterizing part of claim 1.

The material can be obtained by stacking the fibrous layers on top of each other to form a parallelepiped-shaped body, treating the fibrous layers with a water-soluble adhesive, attaching them to each other, and curing a parallelepiped-shaped body to form a cured structure.

More specifically, the method according to the invention is characterized in what is stated in the characterizing part of claim 10.

25

The product according to the invention is typically a large, solid corrugated board "solid block" which can be used for sawing, shaping and pressing for various applications. Particularly preferably, the invention provides corrugated fiber structures having at least one corrugated fiber layer. In this case, the raw material is w 30, e.g. liner reinforced with a board machine, and fluting (medium corrugated board; medium) or fluting alone. Low-quality mixed waste is also suitable for use, which is treated with a curing adhesive in the manufacturing process.

3 104057

As stated above, the water-soluble adhesive used in the invention is preferably water glass or sodium carboxymethyl cellulose. By water glass here is meant sodium silicate (Na2SiO3, NaSiO3-9H2O or Na2Si409), which is soluble in water and bases but insoluble in alcohol and acids. The water glass is alkaline and has a pH in the range of Na 2 O: SiO 2; the higher the ratio, the higher the pH. Generally, the ratio is 1: 1 to 1: 3.1 and the pH is 14 to 10.

Na-carboxymethylcellulose is the sodium salt of a glycolic acid ether derivative of cellulose. It is used as an adhesive for example. wallpaper paste.

10

In addition to the substances set forth above, any substance which, upon drying, forms a strong layer which is soluble in water may be used as a water-soluble adhesive. Typically, such adhesives do not crosslink when cured, whereby the cured structure is still water soluble. Examples of suitable water-soluble adhesives include 15 different animal and cellulose adhesives with a protein matrix.

The fiber layers used in the product according to the invention are preferably composed of paperboard and / or paper pulp, whereby, for example, high yield pulps and / or recycled pulps are particularly preferred. The fiber layer serves to support the adhesive 20 and its quality in itself has no significant effect on the strength properties of the final product. Thus, as noted above, a weak recycled fiber can be used ... for the purpose of the invention. However, the invention requires that the fibrous web be so stiff that the waves do not flatten before the adhesive has time to dry.

For this reason, the surface weights of the fibrous layers prior to the adhesive treatment are generally greater than 100 g / m 2, preferably about 100 to 250 g / m 2. Typically, the fiber structure has a wave height of from about 1 to about 20 mm, preferably from about 3 to about 10 mm, and most preferably from about 5 to about 7 mm.

T

. In applications where the fibrous structure is used, for example, in inner packagings and as a carrier within the structures, the degree of purification of the fiber is irrelevant to the usefulness of the product.

The aqueous adhesive is applied to the fiber layers in an amount of about 10 to 500 g / m 2 to give a surface weight of the cured fiber layer of about 105 to 300 g / m 2.

Preferably, the layers of the fiber structure are moistened throughout with adhesive (impregnation).

The corrugated fibrous structures are made as follows: 5 - The corrugated fibrous layers are arranged on top of each other so as to obtain a "parallelepiped" shaped piece, the fibrous layers are bonded to one another and the parallelepipedic piece is allowed to cure.

A similar technique can be used to make non-corrugated sheets, e.g., by overlapping 4 webs or sheets which are mechanically pressed together (e.g. in a press roll nip) or allowed to snap together. This provides material useful in the building materials and furniture industry, which can be used to replace traditional fiber boards (eg IKI boards). The desired color can be obtained by using a colored cardboard sheet or sheet as the top 15 layers.

According to the invention, the adhesive used is an adhesive which is water-soluble even after drying, whereby the fibrous structure can be pulverized, i.e. mechanically disintegrated in the aqueous phase. Pulping is facilitated in particular by the porosity of the corrugated structure, which allows water to rapidly penetrate the structure, for example through corrugations. The hydropulpper provides a fiber stock that can be recycled and combined e.g.

.. kart on the fly.

Since the fiber structure has maximum compressive strength in the longitudinal direction of the waves, transverse, planar pieces are used to cut the 25 cured bodies, which are used as filler and support structures.

The fiber structures of the invention can be produced from single sheets, wherein the elongated corrugated sheets are treated with water-soluble adhesive on at least 30 other sides, the sheets treated with the adhesive are superimposed so as to obtain a parallelepipedic piece and dry in a parallelepiped shape.

5 104057

According to a preferred embodiment, the fibrous structure comprises overlapping, alternately arranged corrugated and planar fibrous layers ("fluting" and "liner" respectively).

The manufacturing technique described above can also be carried out in a continuous process, comprising the steps of: bonding a fluting and a liner to form a composite web, applying adhesive over the corrugated surface of the composite web, 10 - cutting the composite web sheets of the desired size, arranging the desired number of sheets on top of each other to form a parallelepiped and curing the parallelepipeds.

Water-soluble adhesive can be applied to the surface of the structure in different ways and at different stages of the process. According to one alternative, a parallelepiped-shaped block is first formed and immersed in its entirety in the glue pool. However, it is more preferred to apply the adhesive to at least one surface of the corrugated layer and the planar layer, respectively, by spraying or roller application. Given the configuration of the layers, it is particularly advantageous to apply the adhesive to the corrugated layer by spraying and to the planar layer by spraying or roll.

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According to an alternative to a continuous process, the corrugated and planar fibrous webs are bonded to each other by applying adhesive to the planar web and drying the composite web by infrared radiators. Thereafter, glue is applied to the corrugated surface side and the web is then cut into sheets of desired size, which are superimposed on a fiber block which is allowed to cure, e.g. at elevated temperature.

According to a particularly preferred embodiment, also illustrated in Figure 1, the manufacture of the fibrous structure according to the invention is combined with the manufacture of packaging board by using part of the board for the manufacture of outer packaging and part of the filling. si for the manufacture of a suitable fiber structure. The fiber structure is cut to the desired shape.

6 104057

The outer packaging waste and the fibrous structure cutting waste are all collected and recycled along the same line for the production of a hydropulpper and thus for packaging board.

The invention provides considerable advantages. Thus, the product to be manufactured is very advantageous in terms of its properties and manufacture: cheap raw material, low quality waste paper, lightweight structure; extremely high compressive strength in longitudinal corrugation; 10 - easy to shape; because of the adhesive used in the application, the product can be defibrated like waste paper; the product is typically 100% recycled fiber and glue; industrial product, reinforcement in existing large-scale industrial installations applying the invention 15 or equipment developed according to the invention for good insulation properties (heat, sound); depending on the cutting direction of the product and the nature or quantity of the adhesive, the product is either non-compressible or compressible.

20 It is suitable for a wide variety of applications. The so-called "outer packaging" inserts use environmentally harmful foams to protect the packaging products, such as consumer electronics, ceramics, machinery, equipment, etc. that are easily damaged during transport and handling. The invention makes it possible to replace these inner packing material with a fiber product which can be shaped as required. After use, 25 products can be recycled in use or recycled back to the papermaking industry.

For heavy machinery equipment and similar transport packages, the product is well suited. It may be shaped as required by the object being carried. For these 30 uses, Mote replaces the wood / foam plastic material used in the prior art.

* Still, Mote so is very well suited for roof, wall or floor insulation in house building 7 104057. For this purpose, the product is made into sheets of the desired thickness. Due to its good compressive strength, the product is ideal for eg. as a support for parquet flooring. As an insulating material, the product replaces the so-called. building wool and foam. Water glass, for example, has been known to be used to reduce the flammability of materials, so that the present products are also suitable for use as insulation for partition walls of, for example, hotel or cabin elements.

Other uses of the invention include: in the door structure between the surface plates, the product provides a non-compressible and 10 insulating filler; in furniture frame structures between surface panels, the product is well applicable in the construction of containers (transporters), the product is an excellent material, lightweight, load-bearing and insulating; in the shipping industry, as well as in railway wagons, sheets made from the product are very useful; Sceneries and other exhibition structures

The invention will now be examined in more detail with the aid of a detailed exemplary embodiment.

20

Figure 1 is a schematic diagram illustrating the integration of the process of the invention in the manufacture of packaging (the explanation of this diagram is shown above), and Figure 2 is a simplified diagram of the preferred manufacturing process of the invention.

25

With some additions and modifications according to the invention, the product can be manufactured by conventional corrugating board machines. However, given the logistic factors and the nature of the market, the most sensible solution is to build specialized production lines for this product, as shown in the figure below.

30

As shown in Fig. 2, the liner / fluting rolls 1, 2 are placed in a so-called. unroller (not shown), which enables flying roll change. The fluting structure 1, i.e. fluting, is guided through the pressing nip 3 of the pressing fluting rollers, whereupon the pre-moistened 8 104057 web is fluted.

i The surface paperboard 2, i.e. the liner, is run through one-sided surface sizing 4 whereby a roll of adhesive is applied to one surface by a roller. The corrugated 5 fluting is adhered to the surface board, which adheres to the surface board. In order to adjust the drying of the end product, the laminated product track can be guided, for example, by means of the infrared heated rotating steel belt 6 according to the invention.

Thereafter, glue is applied to the surface of the corrugations by spraying or spraying 7, whereupon the bonded web is guided to a sheet cutting 8, whereby sheets of suitable size are separated and stacked on top of each other 9.

Once the stacks have become large enough they are transferred to a drying oven 10 where they are dried and cured. The resulting solid block 11 can be machined, e.g., by cutting 15 or sawing into pieces of desired size.

As stated above, the adhesive can also be applied to the surface of the paperboard by immersing the parallelepiped formed back and forth in the adhesive, whereby complete absorption occurs.

20

In the experiment according to the invention, a block of about 2,500 x 2,500 x 1,500 mm 3 was made from a single-sided corrugated board having a basis weight of 120 g / m 2. The adhesive used was a water glass solution called Zeocore (Zeofinn Oy, Hamina) with a pH of 11.2 and a density of 1.3. The solution is fluid and easy to apply by both roller and spray application. During manufacture, the corrugated waves were slightly compressed so that their height decreased from about seven millimeters to five millimeters.

The fabricated structure had considerable compression strength in the longitudinal direction of the corrugation but also in the transverse direction was acceptable. In the hydropulpper, the structure was sealed at room temperature ... 40 ° C quite quickly.

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Claims (20)

A recyclable fiber structure comprising - superficial layered fibrous layers which are treated with adhesives and solidified to form a three-dimensional corrugated fiber structure, characterized by - the fiber layers are fully moistened and poured with a water-soluble adhesive, wherein the fiber structure can be suspended in aqueous phase. 10 2. Fiber structure according to claim 1, characterized in that the adhesive is constituted by water glass or carboxymethyl cellulose. Fiber structure according to claim 1 or 2, characterized in that the corrugated fiber material layers are used. 4. Fiber structure according to claim 3, characterized in that the fiber structure comprises alternately corrugated and arranged on top of each other. flat fiber layers. 5. Fiber structure according to any of the preceding claims, characterized in that the layer of fiber material consists of cardboard and / or pulp. • · · 6. Fiber structure according to claim 5, characterized in that the fibrous layer consists of high yield pulp and / or recycled fiber pulp. 25 Fiber structure according to any of claims 3-6, characterized in that the road height is up to 3-10 mm, preferably about 5 - 7 mm. 8. Fiber structure according to any of the preceding claims, characterized by the surface weights of the fiber substance layers prior to the adhesive treatment being about 100 - 250 g / m2. "1 13 104057 Fiber structure according to any of the preceding claims, characterized by water-soluble adhesive being applied to the fibrous layer in an amount of 10 - 500 g / m2, the surface weight of the solidified fiber layer being up to about 105 - 300 g / m2. 5 10. A method of making a fiber structure, according to which - the fibrous layer is arranged on top of each other so as to obtain a piece in the form of a parallelepiped, - the fiber layer is attached to each other with an adhesive, and - the parallelepiped piece is solidified, of that - the fiber substance layer is completely moistened and poured with a water-soluble adhesive, thereby obtaining a solidified piece with a fiber structure that can be slit. 11. A method according to claim 10, characterized in that corrugated fiber material layers are used. 12. A method according to claim 11, characterized in that - elongated corrugated cardboard sheets are treated with a water-soluble glue at least on one side, 20. the sheets treated with glue are stacked on top of each other in numerous pieces to obtain a piece in the form of a parallelepiped, and - the parallelepiped piece is dried at elevated temperature. Method according to claim 11 or 12, characterized in that Flat fiber layers are alternately arranged to form the parallel pipette. Method according to claim 13, characterized in that the fiber structure is formed - by attaching a corrugated fiber web and a fiber web to each other to form a combined fibrous web, 30. by applying glue to the corrugated surface of the combined fibrous web, 14 By cutting the combined fibrous web into sheets of the desired size, - by arranging a desired amount of sheets on top of each other to form a parallelepiped, and 5. by solidifying the parallelepipeds. 15. The method according to claims 11-14, characterized by water-soluble adhesive, is applied to the corrugated surface by spraying. 10 A method according to any of claims 12-15, characterized by a water-soluble adhesive applied to the flat surface by means of a roller. 17. A method according to any of claims 14-16, characterized in that the corrugated and flat fiber webs are adhered to each other by applying an adhesive 15 to the surface of the flat web and by drying the combined fibrous web with infrared radiators. 18. A process according to any of claims 10-17, characterized in that water-soluble glue or carboxymethyl cellulose is used as a water-soluble adhesive. 20 19. A process according to any of claims 10-18, characterized in that the adhesive is applied to the fiber structure in an amount of 10 - 500 g / m2, preferably about 20 - 250 g / m2. Fiber structure according to any of claims 1 to 9 or use of the fiber structure prepared according to any of claims 10-19 as packaging material, insulating material and filling material. : l Λ. S