WO2013041894A1

WO2013041894A1 - Method for manufacturing a foam coating, as well as a spring mattress insert and a foam based article manufactured by the method

Info

Publication number: WO2013041894A1
Application number: PCT/HU2012/000094
Authority: WO
Inventors: Zoltán GAÀL
Original assignee: GAÀLHAB Szivacsfeldolgozó Kft.
Priority date: 2011-09-20
Filing date: 2012-09-19
Publication date: 2013-03-28
Also published as: HUP1100526A2; EP2758460A1

Abstract

On the one hand, the invention is a method for manufacturing a foam coating, in the course of which an object at least partially covered with base adhesive, and foam pieces (22) are fixed to a surface of the object covered with a base adhesive. On the other hand the invention is a spring mattress insert (38) comprising spring construction (10) and foam coating covering springs (12) making up the spring construction (10). Further, the invention is a foam based article, comprising mesh and foam coating covering the mesh.

Description

METHOD FOR MANUFACTURING A FOAM COATING, AS WELL AS A SPRING MATTRESS INSERT AND A FOAM BASED ARTICLE MANUFACTURED BY THE

METHOD

TECHNICAL FIELD

The invention relates to a method for manufacturing a foam coating, as well as a spring mattress insert and a foam based article manufactured with the method.

BACKGROUND ART

Foam remnant and waste, e.g. of polyurethane material, arising in the upholstery furniture industry, foam tailorage, foam manufacturer or foam processing companies or in other fields of application, for example in car dismantling from car seats, can be recycled in a known manner.

Foam remnant or waste is, by way of example, used for manufacturing filling material for cushions. The filling material for cushions is, by way of example, produced by means of a foam grinder, producing foam pieces of various sizes, irregular form and of a typical size ranging between approximately 1-30mm, based on general waste shredding principles.

The cushion filling material may also be manufactured with a disc foam cutting apparatus. In this case, the created pieces of foam are of cuboid shape, with sizes of the sides changing between 4-5 mm, 8-10 mm, and 15-40 mm. If the foam pieces are manufactured by this method, less dusty fractions result than by means of the above manufacturing method. This method ensures manufacturing of cushion filling material of more constant quality, more comfort and flexibility.

Foam remnant is widely used also for manufacturing heterogeneous foam. For this end, foam pieces are used typically produced by means of any one of the aforementioned methods. According to methods known in this field, the foam pieces are mixed in a container filled with polyol, and with a mixture of isocyanate and catalyst otherwise used as basic components of foam manufacturing. In the course of the method, these fluid compounds form a coating on surfaces of the foam pieces, and then generate foam in the spaces therebetween. The mixture thus obtained is then poured into a mold and pressed to a desired density. This method enables the production of hard heterogeneous foams with a density of 60- 200kg/m³ Tatami mats used in the sport industry, as well as footstep sound insulators used in the construction industry can be noted as examples.

A general disadvantage of the current heterogeneous foam production is the use of hazardous materials. A further disadvantage is that only heterogeneous foams of relatively high density can be produced, which does not allow using them in comfort furniture. Low-density heterogeneous foams produced by this method are not durable, because no bond is formed between the foam pieces due to the greater airy space between them. Furthermore, the small-size and dusty fractions do not attach to each other in lack of pressing force.

There are a number of known solutions for decreasing the density of the produced heterogeneous foam and for avoiding use of hazardous materials.

In US 5,800,658 a method is disclosed wherein the foam pieces are covered with water-based rubber, i.e. non-hazardous, adhesive, and are pressed together in a mold. The foam structure thus obtained will receive its final form as mattress insert, cushion or the like in the mold, after drying. In this method, therefore, only a thin layer of adhesive is formed on the surface of the foam pieces. As the end product does not require excessive pressing, the density of the material produced so is approximately identical with that of the foam pieces used. In US 2010/0293814 A1 a method is disclosed wherein the foam pieces are fixed together with water-based adhesive, and then the acquired material is molded. In WO 2010/076170 A2 the application of water-based adhesive is disclosed for attaching the foam pieces. In WO 91/14144 A1 a method is disclosed wherein regular shaped foam pieces are fixed with a water-based adhesive. In US 4,681 ,901 a method is disclosed wherein rubber adhesive and water is separately added to the foam pieces for ensuring the attachment.

A further disadvantage of using heterogeneous foam or recycled foam produced by further known methods as mattress insert, cushion or the like, is that the article thus obtained does not have any reinforcement without a cover of linen or other fabric. This disadvantage arises to a greater extent by lower-density foams. Spring mattress inserts are widely used, wherein noise-suppression and silencing of the springs requires to be solved by preventing the spring turns from colliding to one another. There are a number of known solutions to this problem. In most cases, so-called pocket-springs are made, wherein each coil springs are enclosed in separate fabric pockets, i.e. wrapped, in order to avoid metal parts touching one another inside the mattress. Spring mattress inserts have the advantage, as opposed to solid foam mattresses, to have a higher air permeability capability. All known spring mattress inserts lack a solution of corrosion protection, moreover, the additional costs are high. In the mattress insert according to US 2006/0282954 A1, the individual springs are surrounded by a layer of foam. In US 3,869,739, US 5,537,699 and US 2005/0251920 A1 , the individual springs of the mattress insert are separately enclosed in some kind of material. In WO 2010/117352 A1 a mattress insert is disclosed, wherein springs made of a foam material are combined with springs of metal or with a mattress insert-core of a foam material.

A common disadvantage of the above solutions is the complicated noise- suppression of the springs, which can be accurately implemented at high costs. Further disadvantage is that each spring of the spring construction making up the core of the spring mattress insert requires separate noise-suppression. In view of the above solutions, there is a demand for providing a method for manufacturing a spring mattress insert, foam based article, cushion or the like, with appropriate air permeability characteristics, reinforced by the use of foam pieces. There is also a demand for providing easy, efficient as well as low-cost and low work demand solution for the manufacture, noise-suppression and corrosion protection of spring mattress inserts.

DESCRIPTION OF THE INVENTION

In view of the above requirements, the object of the invention is to provide a method for manufacturing spring mattress insert, foam based article, cushion or the like reinforced by the use of foam pieces. A further object of the method according to the invention is to provide an easy, efficient and low-cost solution for manufacturing, noise-suppression and corrosion protection of spring mattress inserts.

The above objects of the invention can be achieved by the same method, namely spring mattress insert, foam based article, cushion or the like is manufactured in such a way that an object, by way of example a mesh, or a spring construction in the case of spring mattress insert, is coated with foam pieces. Accordingly, the object of the method according to the invention beyond the foresaid aims is to manufacture a comfort appliance, e.g. a seat or a back of upholstered seating furniture, by coating a plurality of various objects with foam pieces. A further object of the invention is to manufacture a mattress insert, wherein the noise-suppression, corrosion protection and arrangement of comfort zones are solved in an easy, efficient and low-cost manner.

The objects are achieved by the method according to claim 1 , the spring mattress insert according to claim 11, and the foam based article according to claim 13. Preferred embodiments of the invention are defined in the dependent claims.

BRIEF DESCRIPTION OF DRAWINGS

Preferred embodiments of the invention are described below by way of example with reference to the following drawings, where

Fig. 1 illustrates a first step of an embodiment of the method according to the invention in a side-view;

Fig. 2 illustrates a first step of a further embodiment of the method according to the invention in a side-view;

Fig. 3 illustrates a second step of an embodiment of the method according to the invention in a side-view;

Fig. 4A illustrates a first sub-step of the second step of a further embodiment of the method according to the invention in a side-view;

Fig. 4B illustrates a second sub-step of the step of Fig. 4A in a side-view;

Fig. 4C illustrates a third sub-step of the step of Fig. 4A in a side-view;

Fig. 5 shows a spring of a spring construction used in some embodiments of the method according to the invention; Fig. 6 shows the spring according to Fig. 5, partially coated with foam pieces;

Fig. 7 illustrates a third step of an embodiment of the method according to the invention in a side-view;

Fig. 8 illustrates the step according to Fig. 7 in a plan view;

Fig. 9 illustrates the step according to Fig. 7 in a perspective view;

Fig. 10 illustrates the step according to Fig. 7 in a perspective view, completing the method step with a different apparatus;

Fig. 11 illustrates a fourth step of an embodiment of the method according to the invention in a side-view;

Fig. 2 illustrates the step according to Fig. 11 in a plan view;

Fig. 13 shows the step according to Fig. 11 in a perspective view;

Fig. 14 shows a detail of Fig. 3;

Fig. 15 illustrates a fifth step of an embodiment of the method according to the invention in a side-view, and also illustrates the mattress insert according to the invention;

Fig. 16 illustrates an apparatus realizing a further embodiment of the method according to the invention in a side-view;

Fig. 17 illustrates an apparatus realizing yet a further embodiment of the method according to the invention in a side-view;

Fig. 18 illustrates an apparatus realizing a further embodiment of the method according to the invention in a side-view.

MODES FOR CARRYING OUT THE INVENTION

According to the invention, various objects can be coated with foam pieces; the coated object in the figures illustrating the exemplary embodiments is a spring construction and a mesh.

Fig. 1 illustrates a first step of an embodiment of the method according to the invention, in the course of which a spring construction 10 made up of springs 12 is placed into a container 14 comprising base (priming) adhesive. In the present embodiment of the method according to the invention, the spring construction 10 is used as an object to be coated with a layer of foam, and hot-melt adhesive is used as base adhesive. The applied hot-melt adhesive is e.g. a self-adhesive synthetic rubber-based hot-melt adhesive. The spring construction 10 may consist of an arbitrary number of springs 12, by way of example steel five-turn coil springs. In the side-view according to the drawing, the coil springs 12 of the external line of the spring construction are illustrated only. The hot-melt adhesive is kept at an appropriate temperature by heating wires 16, namely to ensure sufficiently fluid consistency for the base adhesive. While immersing the spring construction 10 into the base adhesive, the base adhesive sticks to the surface of the springs 12 making up the spring construction 10. In the method according to the invention, such a hot-melt adhesive is preferably used, which maintains its stickiness even after cooling.

A further embodiment of the method according to the invention is different from the above embodiment only in the first step of the method, this first step is demonstrated in Fig. 2. According to Fig. 2, the spring construction 10 is immersed into a container 18 filled with solvent-based base adhesive. The applied solvent- based adhesive can be a solvent-based adhesive used by the upholstery industry, styrene copolymer or rubber-based adhesive, preferably SBS rubber-based adhesive, with 50-60% extract content. In the present embodiment of the method according to the invention, therefore, a spring construction 10 is used as object, similarly to the embodiment according to Figure 1 , however a solvent-based adhesive is used as base adhesive. Similarly to the hot-melt adhesive, the solvent- based base adhesive adheres to the surface of the springs 12. The container 18 without heating is used for storing the solvent-based adhesive, as the solvent- based adhesive is applied at ambient temperature. The container 18 comprises an opening 19 for emptying the adhesive. A common advantage of the hot-melt adhesive and solvent-based adhesive is that while being immersed into the container 14 filled with the hot-melt adhesive or into the container 18 containing the solvent-based adhesive, oil or any other contamination stuck onto the metal wires of the spring construction 10 during the manufacturing process clears off; after immersion, the adhesive surrounds the entire surface of the springs 12 of the spring construction 10, thereby forming a corrosion protection layer thereon. The layer of corrosion protection is essential, because it prevents the corrosion effects of the water-based adhesives applied preferably later.

Fig. 3 illustrates a second step of the embodiments presented in Figs. 1 and 2 of the method according to the invention. In this step, the spring construction 10 is immersed into a container 20 filled with foam pieces. Due to the presence of the base adhesive applied according to the step illustrated in Figs. 1 or 2 on the spring construction 10, the foam pieces stick to the surface of the springs 12 of the spring construction. If foam pieces covered with covering adhesive are scattered on the spring construction 10, an appropriate base is provided for the additional foam pieces of the filling material to adhere. The spring construction 10, however, can be coated with dry foam pieces, as well.

In a further embodiment of the method according to the invention, the step demonstrated in Fig. 3 is performed in a way other than as presented above. In this embodiment, a mattress insert with a plurality of zones is produced. By combining foam pieces of varying rigidity and density, a plurality of, by way of example 3, 5 or 7, comfort zones may be arranged on the sleeping surface of the mattress insert manufactured as an end product (end article). The density of each zone, i.e. the rigidity of the produced mattress insert, is increased by adding, as compared to the other zones, greater amount of foam pieces or foam pieces of different material quality. For example, such an arrangement is conceivable, wherein softer, less dense foam components are allocated at the head, shoulder and feet zones, while material of higher density is arranged at the waist zone. For sitting surfaces, identical spring constructions may be arranged with different characteristics of rigidity and flexibility by varying the type and amount of the foam pieces to be filled.

In Figs. 4A to 4C, a comfort zone arrangement is illustrated. According to Fig. 4A, prior to immersing the spring construction 10 covered with base adhesive into the container 20, only a smaller amount of foam pieces 22 is preferably arranged therein. The remaining amount of foam pieces 22 for coating the spring construction 10 is scattered onto the spring construction from above while placed in the container 20. Comfort zones are arranged by means of covering mask 23 shielding some parts of the spring construction 10 from being scattered with foam pieces 22, so as to allow foam pieces 22 of another type to be scattered thereon. Therefore, in the first step of the embodiment according to Fig. 4A, foam pieces 22, e.g. of higher rigidity and density, are placed only on the mid-section of the spring construction 10. If foam pieces 22 of higher rigidity and density are scattered onto a mid-section of the spring construction 10, then the mattress insert 38 thus produced as end product will preferably be more rigid and resistant around the waist area.

In a sub-step demonstrated in Fig. 4B, the mask 23 is removed, and onto the remaining parts of the spring construction 10 additional foam pieces 22 are scattered, expediently of different density, in this case softer and less dense pieces, than those scattered thereon already. The additional foam pieces 22 are scattered substantially evenly on the spring construction 10, or are evenly dispersed after scattering. In a sub-step demonstrated in Fig. 4C, the foam pieces 22 scattered over the spring construction 10 in the container 20, preferably are subjected to pressing by means of a compressing element 24. With pressing increases the sticking of the foam pieces 22 to the spring construction 10, moreover, repeated pressing will increase the amount of foam pieces reaching into between the rings of the springs. Compression of the spring construction 10 is especially important as the strength of the adhesive sticking between the spring construction 10 and the foam pieces 22 is increased by pressing their surfaces together, since a sticking of appropriate strength is formed by the base adhesive under pressure.

Fig. 5 illustrates a coil spring comprising part of the spring construction 10, preferably a tempered steel coil spring, prior to immersion of the spring construction 10 into the container 20 filled with foam pieces, while Fig. 6 illustrates it afterwards. Figs. 5 and 6 illustrate, by way of example, a 5-turn coil spring. Fig. 6 shows the foam pieces 22 adhering to the spring 12. The foam pieces 22 approximately fill the space between the springs 12, nevertheless, for the sake of better understanding only a few foam pieces 22 are illustrated. The foam pieces 22 are small enough so as to adhere to the spring 12 in a manner not hindering its movement, coating the surface of the spring 12 as completely as possible. In case of excessive, dynamic use, collision of the turns of the springs is prevented thereby.

The flexibility characteristics of the spring construction 10 can also be modified e.g. by immersing the spring construction 10 into the base adhesive only partially, whereby in lack of a base adhesive on given parts of the spring construction 10 there will be no foam pieces 22 adhering thereto, and the desired parts will not be covered with foam coating. Applying initial pressure to those parts of the spring construction 10 with a foam coating, it will exhibit the same characteristics as without foam coating, however, increasing the pressure, the spring will show a substantially exponential increase of resistance approximating the total compression.

Fig. 7 shows a third step of above embodiments of the method according to the invention, following the second step illustrated in Fig. 3 or Figs. 4A-4C. In this step, the spring construction 10 immersed into the containers 16 or 18 filled with base adhesive and in container 20 filled with foam pieces 22 is placed onto a supporting structure 26 and additional foam pieces 22 are scattered thereon in order to "thicken" the spring construction 10. The additional foam pieces 22 can previously be moistened by a covering adhesive, preferably by a water-based covering adhesive in order that additional foam pieces 22 adhere to the foam pieces 22 already adhered to the spring construction 10. Thickening of the spring construction 10 is also possible by spraying covering adhesive over the foam pieces 22 already adhered to the spring construction 10, thereby achieving appropriate sticking of additional, in this case dry, foam pieces 22. The applied covering adhesive e.g. may be a water-based adhesive of the upholstery industry, namely a non-solvent rubber adhesive. The covering adhesive ensures sticking of additional foam pieces 22 to the foam pieces 22 adhered to the spring construction 10. On the figure shutter elements 28 are also visible, which are actuated by means of slave cylinders 33 of a hydraulic press in the present embodiment. The foam pieces 22 are scattered on the area bordered by the shutter elements 28. The supporting structure 26 and the spring construction 10 placed thereon are represented in a plan view in Fig. 8. This figure illustrates movable shutter elements 28, corner elements 30, the spring construction 10 itself, and hydraulic presses 32, as well as their respective slave cylinders 33, which are used to move, i.e. slide, the shutter elements 28 on the supporting structure 26. The shutter elements 28 and corner elements 30 border the area, over which additional moistened foam pieces 22 are scattered. The dimension of this area can be varied by moving the shutter elements 28 via the slave cylinders 33, which will be described in greater detail by later steps of the present embodiment of the method. In the present embodiment of the method according to the invention, therefore, the method is carried out on a supporting structure 26, by placing the object between shutter elements, at least one, or specifically two, of shutter elements are moveable shutter elements 28, and the foam coating is compressed by means of actuating the movable shutter element 28. In the present embodiment of the method, the spring construction 10 is preferably centrally placed between the open shutter elements 28, namely in such a manner that the sides of the spring construction 10 are at substantially identical distance from each individual shutter element 28, respectively.

The moistened additional foam pieces 22 can be introduced to the area bordered by the shutter elements 28 and corner elements 30 so as to reach the space between the springs, i.e. the inner space of the spring construction 10, as well as between the rings of the springs 12, and to surround the wire of the coil spring 12. The corner elements 30 prevent foam pieces getting out from among the shutter elements 28. In some embodiments of the method according to the invention, the method is carried out in such a manner that onto the spring construction 10 covered with covering adhesive, smaller, e.g. 4 x 8 x 20 - 30 mm, foam pieces are applied, which mostly fill the space between the springs 12. The additional foam pieces 22 scattered over the spring construction 10 partially coated with foam pieces are of cuboid shape, e.g. foam pieces of 8 x 25-30 x 50-100 mm in size. The sticking between the two different types of foam pieces 22 is formed by means of covering adhesive applied onto the originally introduced foam pieces 22 and/or the additional foam pieces 22.

The present step of the method according to the invention is illustrated in Fig. 9 in a perspective view, prior to the moistened additional foam pieces 22 being introduced into the area bordered by the shutter elements 28 and corner elements 30. The figure shows the foam pieces 22 adhered to the spring construction 10 placed onto the supporting structure 26. The supporting structure 26, the movable shutter elements 28, the corner elements 30, the hydraulic press 32 and its slave cylinders 33 give parts of a mattress compression apparatus serving as manufacturing mold.

Fig. 10 illustrates the above step, as well. According to Fig. 10, the step is completed by means of a mattress compression apparatus other than the one demonstrated in Fig. 9. According to the figure, in the mattress compression apparatus, on a supporting structure 35, the shutter elements 28 are moveable by actuating means 36 along rails 37. Linear movement along the rail 37 may be carried out based on any linear actuation principle, e.g. using right-hand or left- hand screw or by means of pneumatics. The steps of the method according to the invention can be carried out equally by means of the presented various mattress compression apparatuses. In the next step of the method according to the invention illustrated in Fig. 11 , the moistened additional foam pieces 22 introduced into the area bordered by the shutter elements 28 and corner elements 30, namely the foam coating produced on the to-be-coated object is compressed by actuating the moveable shutter elements 28, and by moving the upper shutter element 34 in the direction of the spring construction 10.

Compression can be made also in such a manner that only a few, e.g. one, of the shutter elements 28 or the upper shutter element 34 is moved. If compression is carried out by actuating the upper shutter element 34 exclusively, then the additional foam pieces 22 are just as well compressed into a space-portion of cuboid shape, i.e. in case of an appropriate compression rate, a spring mattress insert 38 (shown in Fig. 15) of substantially a cuboid shape will be obtained by the method. For this end, the foam pieces 22 are preferably introduced into the area bordered by the shutter elements 28 and corner elements 30 exceeding the height of the spring construction 10. It is the role of the movable shutter elements 28, therefore, to define the size of the mattress insert 38, in addition to the side-way compression applied thereby. The individual shutter elements 28 are preferably moveable, independently from one another. To move them together is advantageous to cause to produce a layer of substantially identical thickness made up of foam pieces 22 surrounding the spring construction 10, as a result of substantially identical movement of them. Fig. 12 shows the step of the method illustrated in Fig. 11 , in a plan view. Accordingly, in the Fig. 12, the shutter elements 28 responsible for side-way compression are shown in a pushed-in position. It is also evident from the figure, that by the inward movement of the shutter element 28, the corner elements 30 pull inwards along the inner surfaces of the shutter elements 28. The water-based covering adhesive is advantageously applied onto the surface of the foam pieces in a thin layer. The compression shown in Figs. 1 and 12 facilitates pressure sticking and cross-linking of the base adhesive and the covering adhesive used by the method. Although not shown in the drawings, following this step, drying of the base adhesive and covering adhesive can be speeded up by use of microwave radiation and/or hot air drying.

While introducing the moistened additional foam pieces 22, it is advantageous to ensure feeding the foam pieces 22 with catalyst, so as to facilitate solidification of water-based covering adhesive and to form a sticking to the foam pieces 22 adhering with base adhesive to the spring 12. Fig. 13 shows the step of Fig. 12 in a perspective view. On the figure compressed the foam pieces 22 can be seen, which form a side layer of foam around the spring construction 10.

Fig. 14 shows a detail of Fig. 13. As seen in the figure, there are foam pieces 22 compressed to form a side layer of foam around the spring construction 10, as well. Additional foam pieces 22 are naturally found in the inner space of the spring construction 10, just as in the space above the spring construction 10, which, for the sake of better understanding, are illustrated only in the Figs. 7, 8, 11 , 12, and 13 representing the plan view.

For the sake of visibility, the upper shutter element 34 bordering the compressed mattress insert 38 from above is not shown in either one of Figs. 12-14.

The amount, quality of the introduced additional foam pieces 22 as well as the rate of compression determine the rigidity of the mattress insert 38. By appropriate modification of these parameters within the mattress insert 38, various, by way of example head, shoulder and waist, comfort zones can be arranged in a way as illustrated in Figs. 4A-4C.

Fig. 15 shows the end product (end article) of the above detailed embodiment of the method according to the invention, namely the mattress insert 38 according to the invention. It can be seen in the figure, that the mattress insert 38 is compressed by means of the upper shutter element 34 from above, while shutter elements 28 ensure side-way compression. There is less compressed, looser foam coating inside the spring structure 10. From above as well as on all sides, the mattress insert 38 is coated with a layer of foam formed of compressed foam pieces 22. The mattress insert 38 is placed onto the supporting structure 26 during the manufacturing method, therefore, there is not any foam layer formed on the underside according to the figure of the spring construction 10. One such mattress insert 38, by way of example, may serve as a bed mounted onto a fix surface.

In the present embodiment of the method according to the invention, it is also possible to manufacture a mattress insert 38 with a layer of foam on both of its greatest surfaces, if sufficient amount of foam pieces 22 is introduced into the area bordered by the support structure 26 and shutter elements 28 to form a sleeping surface of the to-be mattress insert 38 prior to placing the spring construction 10 therein. In all of the cases, shutter elements 28 are used of a height at least equal to or preferably higher than the desired height of the mattress insert 38.

By using a spring construction arranged with appropriate dimensions, e.g. spring sitting piece or other spring comfort seating piece can be manufactured according to the present embodiment of the method according to the invention. As opposed to solid foam mattresses, the use of mattresses with spring construction is advantageous due to better air permeability characteristics.

After a certain curing time, the mattress insert 38 is removed from the mold formed by the shutter elements 28. Total drying of the mattress insert is advantageously completed in a microwave dryer or by hot air drying. After complete drying, the uneven surfaces of the mattress insert 38 are preferably evenly cut e.g. with a foam-cutter machine. By means of adhering additional cushions, the shape of the thus produced mattress insert 38 may be further modified, or upholstered. According to above disclosed embodiments of the method according to the invention, a spring mattress insert 38 is manufactured. The manufactured spring mattress insert 38, accordingly, comprises a spring construction 10 and a foam coating surrounding the springs 12 making up the spring construction 10, which foam coating is manufactured in accordance with above disclosed embodiments of the method according to the invention. In the spring mattress insert 38, therefore, additional foam pieces 22 moistened with covering adhesive are fixed to the foam pieces 22 bonded to the coil springs 12 with base adhesive forming a corrosion- resistant covering.

The method according to the invention, namely the manufacture of foam coating, is preferably used for manufacturing other foam based articles as well. Such as, e.g. a quilt made of foam pieces, e.g. of foam waste. The manufacturing method of the quilt, namely a production line is illustrated in Fig. 16. Accordingly, all embodiment of the method according to the invention relates to manufacturing method of foam coating, wherein the object is at least partially coated with foam in such a manner that the object is covered with base adhesive, and foam pieces are bonded to the surface of the object forming a foam coating. To the surface of the object covered with base adhesive are fixed foam pieces 22 advantageously moistened with covering adhesive, nevertheless, dry foam pieces may also be fixed. According to the embodiment of the method according to the invention illustrated in Fig. 16, a mesh 42 is unwound from a drum 40. The mesh 42 is a carrier, namely serving as a support structure, reinforcement for the foam based article, e.g. quilt, produced as the end product of the method, or holding its greater surface areas together. A given portion of the mesh 42 is passed into a container 50 filled with base adhesive, preferably a solvent-based base adhesive. In the container 50, the part of the mesh 42 passing through the container 50 is covered with base adhesive. Appropriate rate of immersion of the mesh is ensured by the position of the cylinder 44 relative to the level of the base adhesive 48.

The given portion of the mesh 42 leaves the container 50 as adhesive-covered mesh portion 56 and passes to the container 52 arranged on the stand 53, wherein foam pieces 54 are accumulated. The accumulated foam pieces 54 have side sizes ranging e.g. between 4-5 mm, 8-10 mm, 20-100 mm, respectively. In the container 52, the foam pieces 54 stick to the surface of the mesh portion 56, thereby producing mesh portion 58 coated with foam pieces 54. A mesh portion 58 of a given length coated with foam pieces 54 forms the end product of the present embodiment of the method according to the invention. The mesh portion 58 is wound on drum 60 being arranged on stand 62. It is evident from the figure, that the width of the mesh 42 unwound from the drum 40 is significantly different from the width of mesh portion 58 coated with foam pieces 54 wound onto drum 60 due to the thickening with foam pieces 54. The container 52 may comprise dry foam pieces 54 and/or moistened with base adhesive.

The end product of the hereabove presented embodiment of the method according to the invention is a foam based article mesh portion 58 coated with foam pieces, by way of example, quilt or cushion. The wound-up foam based article manufactured according to the method is suitable, folded in multiple layers, sewn, quilted and glued, for producing upholstery cushions and quilts.

By the method according to the invention illustrated in Fig. 16, preferably such foam based article, namely e.g. quilt or cushion, is manufactured, which is not compressed, and its structure remains loose. In this preferred embodiment, dry foam pieces 54 are used, bonding only to the mesh 42, and not to other foam pieces 54. By applying 5-10 layers of the foam based article thus obtained, quilt and cushion products may be fabricated. Note that foam pieces 54 moistened with covering adhesive adhere advantageously to the mesh 42 covered with base adhesive 46. In the case when foam pieces 54 moistened with covering adhesive are applied, by folding the foam based article, the foam pieces 54 making up each layer of the mesh 42 advantageously adhere to each other. An advantage of the article manufactured in the present embodiment is that the foam pieces 54 do not dislocate compared to each other, because the fixing effect of the mesh 42; the mesh 42 reinforce the foam based article, but the structure of the article remains loose. The foam based article thus manufactured is advantageously applicable for producing back cushions for furniture. If, therefore, moistened foam pieces 54 are applied, then sticking is ensured between the foam pieces 54. Hence, by folding the foam based article and placing it into a mold, then back cushions can be manufactured thereof in an easy-to-shape manner. These, by way of example, can substitute furniture cushions filled with a mixture of cut foam and silicon cotton. The cushion structure thus obtained has favorable shape retaining capability in addition to being highly flexible and lightweight.

Fig. 17 shows an embodiment of the method according to the invention similar to the embodiment of Fig. 16. This embodiment has an end product of three-layer foam based article coated with foam pieces 54', although, manufacturing of a foam based article with a number of layers other than three is also possible. Accordingly, meshes 42', 42", 42"' are separately unwound from drums 40', 40", 40"', respectively. In the illustrated embodiment, each drum 40', 40", 40"' is mounted onto the same stand 41'. Being unwound from the drums 40', 40", 40"', the meshes 42', 42", 42"' are immersed, by means of a cylinder 44, into a container 50 filled with base adhesive 46. Mesh portions 56', 56", 56"' covered with adhesive leave the container 50, which then pass into container 52' comprising foam pieces 54', preferably moistened with covering adhesive. As seen in Fig. 17, there are three openings arranged on the container 52' for receiving the mesh portions 56', 56", 56"' into the inner part of the container 52' filled with foam pieces 54', as opposed to container 52 illustrated in Fig. 16, arranged with a single opening only.

In container 52', the foam pieces 54' adhere to the surface areas of the mesh portions 56', 56", 56"' covered with adhesive, and by leaving the container 52', therefore, the adhesive-covered mesh portions 56', 56", 56"' form mesh portions 58', 58", 58"' coated with foam pieces 54'. The cylinders 64, 64' ensure that the mesh portions 58', 58", 58"' are guided via separate routes. After leaving the container 52', the mesh portions 58', 58", 58"' pass through a line of cylinders made up of cylinders 66, 66', 68, 68', 70, 70', in the course of which several layers of meshes 58', 58", 58"', i.e. the end product of foam based article, e.g. quilt, are compressed by being pressed to one another. The foam based article obtained by compressing a part of the mesh portions 58', 58", 58"' of a given length, passes through a, preferably high-frequency (microwave), dryer 72, then a hot air dryer 73. By passing through the dryers 72, 73, the base adhesive applied to the meshes 42', 42", 42"' cures. In certain embodiments only one of the high- frequency (microwave) dryer 72 or hot-air dryer 73 is applied. After drying by means of the dryers 72, 73, the three-layer foam based article 62' formed of a given length of mesh portions 58', 58", 58"' coated with foam pieces 54' is wound onto a drum 60' arranged on stand 62'.

In the embodiment shown in Fig. 16, similarly to the present embodiment, high- frequency dryer 72 and/or hot-air dryer 73 can be arranged after the container 52 and before winding up mesh portion 58 coated with foam pieces 54' onto the drum 60. Foam pieces 54, 54' comprised in the container 52 shown in Fig. 16, or in the container 52' shown in Fig. 17, in the case when not the above detailed loose- structure quilt is intended to be produced, may be covered with covering adhesive, preferably with a water-based covering adhesive. Covering the foam pieces 54, 54' with a covering adhesive facilitates the adherence of the foam pieces 54, 54' to one another, namely "thicken" the layer of foam being formed on the mesh portion 56, 56', 56", 56"' covered with adhesive. Covering the foam pieces 54, 54' with a covering adhesive, or possibly with an adhesive different in its material than that of the base adhesive does not hinder adherence of the foam pieces 54, 54' onto the adhesive-covered mesh portions 56, 56', 56", 56"', however facilitates adherence of foam pieces 54, 54' to each other. The quilts manufactured as end product of the methods illustrated in Figs. 16, 17 may also be subjected to compression, if not the above detailed loose-structure quilt is to be produced, preferably prior to drying of the base and covering adhesives applied in the method. As a matter of fact, compression facilitates cross-linking of the adhesives and will result end product of higher quality, namely a foam based article.

The single- and three-layer foam based articles manufactured by the embodiments of the method according to the invention illustrated in Figs. 16 and 17 have a wide- range of applicability. These can e.g. be applied as a base component of footstep sound insulation used in the construction industry. A further application may be geotextile for separating concrete and asphalt layers used in road construction works. Use in the road construction works is not preferable in such applications where it is subjected to direct frost danger, due to the hygroscopic nature of the foam based articles. The obtained articles can also be similarly used in the upholstery furniture industry as felt for coating upholstery spring constructions. In this manner it can be used, e.g. for coating the mattress insert 38 according to the invention, moreover, the foam based article, in a moist state, bonds to the material of the mattress insert 38.

A further embodiment of the method according to the invention is illustrated in Fig. 18. The end product of the embodiment illustrated in the figure is a foam based article, a foam block, manufactured by use of foam pieces 98 and mesh 89, by applying compression according to the figure.

In a manner as illustrated in Fig. 18, the mesh 89 is unwound from a drum 88 arranged on scaffold stand 86. The mesh passes through a container 90 comprising, similarly to the embodiments illustrated in Figs. 16 and 17, a base adhesive, preferably a solvent-based adhesive. Upon exiting the container 90, a given portion of the mesh 89 will become adhesive-covered mesh portion 91. The adhesive-covered mesh portion 91 then enters a container 96 filled with foam pieces 98. The foam pieces 98 stick to a given surface of the adhesive-covered mesh portion 91 , thereby upon exiting the container 96 a mesh portion 93 coated with foam pieces 98 is formed. In this embodiment, the foam pieces 98 in the container 96 may be covered with some covering adhesive, preferably a water- based covering adhesive, similarly to the embodiments illustrated in Figs. 16 and 17, when arriving from a conveyance belt 78, or may reach the container 96 in any other way. A mesh portion 93 leaves the container 96 coated with foam pieces 98, which, in consequence of being moistened with the covering adhesive is preferably appropriately thickened with foam pieces 98 in the container 96. The direction of passage of the mesh portion 93 is determined by a coil 100. The mesh portion 93 passes from the coil 100 to a pulley pair 101. The pulley pair 101 moves with an alternating motion over the compression cart 102, continuously laying sheet-by- sheet, into the compression cart 102 the appropriate layers of the mesh portion 93 coated with foam pieces 98. As the compression cart 102 is filled up with layers of mesh portion 93 coated with foam pieces 98, a press plate is placed on the open top of the compression cart 102 and the compression cart 102 is moved under a compression unit 106. The compression unit 106 compresses the foam based article made up of appropriate layers of mesh portion 93 coated with foam pieces 98 to a given height, i.e. block 110 (shown inside of a dryer 108). An exemplary final state of the compression unit 107 is shown in Fig. 18. The block 1 0 is removed from the compression cart having a sidewall which can be opened and is dried in, e.g. microwave, a dryer apparatus 108. The block 110 may be used as basic component in the upholstery industry, applying commonly used foam cutting methods, similarly to homogenous foam blocks. The use of the mesh 89 facilitates the aforementioned procedure of the method, and contributes to the layerability of the acquired mesh portion 93, furthermore ensures a layered structure of the block 110 obtained as an end product of the present embodiment of the method according to the invention.

Similarly to what is illustrated in Fig. 16, in the end product, in this case there is also a mesh arranged to provide for increased structural strength. In the embodiment illustrated in Fig. 16, expediently foam pieces 54 of smaller size may be applied, e.g. in the present embodiment foam pieces 98 with respective side lengths ranging between 8-10 mm, 15-40 mm and 50-100 mm are used. By means of the block forming method disclosed in the present embodiment, blocks ranging in density from 20 kg/m³ to 100 kg/m³ can be manufactured; the density can be modified by the appropriate adjustment of the press. The end product manufactured in the present embodiment is characterized by the reinforcing effect of the mesh being part of the entire structure. The end product can be manufactured in a wide range of density as per the disclosed manner.

In the embodiments of the method according to the invention illustrated in Figs. 16- 8, a foam based article according to the invention is manufactured, comprising mesh 42, 42', 42", 42'", 89 and a foam coating covering the mesh 42, 42', 42", 42"', 89, which is manufactured by the method as presented in Figs. 16-18. The foam based article manufactured according to the embodiment of the method according to the invention illustrated in Fig. 17, comprises at least two, in the illustrated embodiment three, meshes 42', 42", 42"', wherein the foam coatings are separately produced by the method according to the invention, and the at least two meshes 42', 42", 42'" coated with foam are compressed to one another in a layer forming manner.

According to some embodiments of the method according to the invention, such foam based article is manufactured, wherein additional foam pieces 54, 54', 98 moistened with covering adhesive are fixed to the foam pieces 54, 54', 98 with base adhesive. According to the embodiment of the method according to the invention represented in Fig. 18, a foam based article is manufactured, wherein the at least one mesh coated with foam is arranged in a layered way, and the foam based article is compressed.

In every embodiment of the method according to the invention, such foam pieces are preferably used, which are produced by a shredding machine from, preferably polyurethane, foam in such a manner that each side of the foam pieces has a cut surface. The input material fed into the shredder is preferably some foam remnant or waste, whereby the method according to the invention is, as a matter of fact, a method for waste recycling. The dimensions of the foam pieces can be adjusted by means of the shredding machine. The above shredding machine may be a disc cutting machine, whereby foam pieces can be produced in the form of strips (e.g. with size between 4 x 8 x 20 mm and 4 x 8 x100 mm) or sheets (e.g. with size between 8 x 20 x 50 mm and 10 x 40 x 100 mm) during the manufacturing method of approximately identical dimensions. The shape of the foam pieces in both cases is close to cuboid. According to the procedure of the disc production line, less dusty fractions are produced; a more comfortable and resilient cushion filling material of higher and more even quality is manufactured than by means of granulation, e.g. by simply cutting foam pieces. The oblong or flat foam pieces can be used in various methods according to the invention, as desired.

The foam pieces used in the method according to the invention, may be one type of foam or foam remnant, waste, or could originate from different types of foam wastes.

The applied foam waste typically comprises a plurality of different types of foams, therefore, the selection of the foam pieces according to types means a significant part of the preparatory processes. Foam pieces of identical type may be made an end product of better quality. In the especially preferred embodiments of the method according to the invention, recycled base components are used, therefore the especially preferred embodiments of the method according to the invention are methods for recycling foam waste.

By means of the method according to the invention, any metal, wood, plastic object, furniture frame, bonell spring, wave spring, wood spring, wooden frame arranged with spring construction can be coated with foam by immersing in base adhesive and passing through a container filled with foam pieces, or bathing in a container filled with foam pieces. In accordance with the above, surface treatment of objects to be coated can be omitted when solvent-based adhesive or hot-melt adhesive is applied as base adhesive. By the use of mesh it is also possible to manufacture furniture seat, back cushion, or ready-made furniture, such as lounger, armchair, sofa by means of appropriate mold. If the applied foam pieces are covered with covering adhesive, the foam layer on the surface of the object can be thickened. The unnecessary excess foam adhering to the object surface can be removed or the given surfaces can be formed to have an even surface, cut, or the object coated with foam thus acquired may be covered with some textile. In case of a mattress insert arranged with bonell springs, the use of the method can eliminate the necessity of stiffening foam i.e. so-called "bonell-block", to be introduced between the spring coils.

An advantage of the method according to the invention is that the joint use of the base adhesive, typically solvent-based, or especially preferably in the case of metal objects, hot-melt adhesive, and the covering adhesive applied onto the surface of the foam pieces will form an adhesive sticking between the coated object and the foam pieces. According to the invention, substantially any furniture piece can be coated with foam. Depending on compression rate, in some embodiments of the method according to the invention, the density of the produced end product is freely variable, i.e. the end product could have a density lower than that of the initial foam itself. In those embodiments of the method according to the invention, in the course of which a mesh is used, the applied mesh may be, e.g. a bird mesh or fishing net. The material of the used mesh may preferably be polyamide, polyethylene, polypropylene, polyester, or a mesh made of polyurethane foam sheet. If the material of the mesh is hygroscopic, the applied base adhesive can also be a water-based adhesive. In some embodiments of the method according to the invention, therefore, in the case of hygroscopic objects to be coated, a water- based adhesive is used as base adhesive. The hot-melt adhesive used in some cases is not hazardous to health. The solvent-based adhesives may be hazardous due to the solvent presence. If the used mesh is plastic, then it is advisable to use solvent-based adhesive as base adhesive. On non-hygroscopic surfaces, it is again more appropriate to use a solvent-based adhesive as base adhesive. Metal and wooden objects, synthetic materials do not form a sticking with the foam pieces by means of water-based adhesives. If synthetic mesh is used, it is advisable to use a solvent-based adhesive as base adhesive, because most plastic materials melt at the application temperature of the hot-melt adhesive. Use of water based, e.g. rubber, covering adhesives is preferred as they do not generate foam between the foam pieces, but rather form a thin surface layer on the foam pieces bonding them to one another. The water-based adhesive is not hazardous to health, so it can be applied for further procedures without the use of any special protection means.

In accordance with the above, therefore, in a number of embodiments of the invention, additional foam pieces can be fixed with covering adhesive to the foam pieces fixed to the object to be covered with base adhesive.

The invention is, of course, not limited to the preferred embodiments described in details above, but further variants, modifications and developments are possible within the scope of protection determined by the claims.

Claims

1. A method for manufacturing a foam coating, in the course of which an object is at least partially coated with foam,

characterized by

- covering the object at least partially with a base adhesive (46, 94), and

- fixing foam pieces (22, 54, 54', 98) to a surface of the object covered with the base adhesive (46, 94).

2. The method according to claim 1, characterized by fixing foam pieces (22, 54, 54', 98) moistened with covering adhesive to the surface of the object covered with the base adhesive (46, 94).

3. The method according to claims 1 or 2, characterized by fixing additional foam pieces (22, 54, 54', 98) moistened with covering adhesive to the foam pieces (22, 54, 54', 98) being fixed to the object with base adhesive (46, 94).

4. The method according to claim 3, characterized by scattering the additional foam pieces (22, 54, 54', 98) moistened with the covering adhesive on the object.

5. The method according to any of claims 2 to 4, characterized by using solvent-based adhesive or hot-melt adhesive as base adhesive (46, 94), and water-based adhesive as covering adhesive.

6. The method according to any of claims 2 to 4, characterized by using water- based adhesive as base adhesive (46, 94) and as covering adhesive, as well, for a hygroscopic object.

7. The method according to claim 5 or 6, characterized by compressing the foam coating at least from one direction.

8. The method according to any of claims 1 to 7,

mesh (42, 42', 42", 42"', 89) as the object.

9. The method according to any of claims 1 to 7, characterized by using a spring construction

(10) as the object. 0. The method according to claim 9, characterized by carrying out the method on a supporting structure (26), the object being placed between shutter elements, the shutter elements comprising at least one moveable shutter element (28) and/or one moveable upper shutter element (34), and the foam coating is compressed by means of actuating the moveable shutter element (28) and/or the moveable upper shutter element (34).

11. A spring mattress insert (38), comprising

- a spring construction (10) and

- a foam coating covering the springs (12) of the spring construction (10), characterized in that the foam coating is manufactured with the method according to claims 9 or 10.

12. The spring mattress insert (38) according to claim 11 characterized in that additional foam pieces (22) moistened with covering adhesive are fixed to the foam pieces (22) fixed to the springs (12) with the base adhesive.

13. A foam based article, comprising

- a mesh (42, 42', 42", 42"', 89),

- a foam coating covering the mesh (42, 42', 42", 42"', 89),

characterized in that the foam coating is manufactured with the method according to claim 8.

14. The foam based article according to claim 13, characterized by comprising a single mesh (42), and foam pieces (54) are fixed to the mesh (42) with base adhesive (46).

15. The foam based article according to claim 13, characterized by

- comprising at least two meshes (42', 42", 42"'), on which the foam coating is manufactured separately with the method according to claim 8, and

- the at least two meshes (42, 42', 42") coated with foam are compressed to each other in a layer forming manner.

16. The foam based article according to any of claims 13 to 15, characterized in that additional foam pieces (54, 54', 98) moistened with covering adhesive are fixed to the foam pieces (54, 54', 98) fixed to the mesh (42, 42', 42", 42"', 89) with base adhesive (46, 94).

17. The foam based article according to any of claims 13 to 16, characterized in that the at least one mesh (89) coated with foam is arranged in a layered manner.