FI85032C - KOMBINATIONSFILT OCH FOERFARANDE FOER DESS FRAMSTAELLNING. - Google Patents

Description

1 85032

Composite felt and method of making it

The invention relates to a composite felt with at least two fibrous layers of different materials.

The invention mainly relates to a composite felt intended for the coating of structures, such as the so-called As a substrate-side layer for PVC mats and the like sandwich structures. This layer today consists of something called of nonwoven fibrous material, which may also be more or less covered with some foam as required. 10 The purpose of the layer is to act as a load-bearing structure of the sandwich structure, and at the same time it can serve other purposes, such as sound attenuation (room space) and leveling of surface irregularities and, for example, thermal insulation.

A sandwich coating is usually made by applying a resin, e.g. PVC, to one surface of a fibrous layer in the form of a paste. The paste is absorbed into the fibrous structure and, after curing, forms a good bond with it. The paste layer is grown on 20 fibrous layers to the desired thickness, e.g. 0.5-2 mm, and finally the desired decorative pattern is printed on its outer surface.

The fibrous layer is usually a felt made of jute or synthetic fibers such as mineral, plastic, ceramic, or the like. The fibers are randomly oriented in the so-called staple fibers, i.e. fibers with an average length of about 5 mm and an average thickness of 4-10 μπι. They are bound together by some glue or they can be needled 2 85032. In a few products, especially in older coatings, the fibrous layer may be a woven or mesh-like structure. In general, it has a thickness of 1 to 10 mm and a weight of 40 to 400 g / mJ.

5 Only one type of fiber is used in the known fiber layers, i.e. the entire load-bearing fibrous layer consists of one and the same fibrous material. In this case, the fibrous material and its structure have to be chosen on the basis of a compromise, so that the properties required of the coating can be optimized as cheaply as possible. In order for the adhesion between the paste and the fiber to be reliable, the fibrous structure must be quite transparent, i. its weight per unit area is small-like. This means that the paste fits quite deeply into the structure of imey-15, i.e. pasta sales are high. Due to the low density, the step sound attenuation of the felt is also lower than desired and its ability to smooth out the unevenness of the substrate is also worse than expected. Thus, in order to increase the vibration damping capacity and load-bearing capacity 20, a denser fiber must be used at the expense of adhesion.

Attempts have also been made to solve the adhesion problem in such a way that a thin open fibrous layer with a weight of about 40 g / m * is placed in the paste layer, i.e. a rather light fibrous structure. This layer is quite close to the actual felt, however, at a distance that can accommodate a thin layer of pasta in between. Due to the small distance, the fibrous layer surfaces partially extend into each other's structures, thus providing adhesion between the fibers 30, which is reinforced by a thin layer of paste. Upwards, i.e. towards the decorative surface, this open layer of 3,85032 fibers now provides a relatively large adhesive surface with a relatively small paste. The actual felt layer can now be of a denser quality, perhaps weighing up to 400 g / m2. The weight is limited by the adhesion between the adhesive layer and the actual felt. The adhesive layer is often fiberglass fiber and is used especially when the actual felt layer contains foamed PVC or the felt layer is completely replaced with foamed PVC.

10 It has also been found that natural fibers, such as jute, are good compromise materials when fresh. However, these have the disadvantage of deteriorating over time. They are not as elastic as synthetic fibers, but return less to their initial state when the stress is removed from the coating, making it easier to leave permanent deformations. Moreover, these fibers cannot withstand the strain of molds and bacteria that often arise in the windless and often moist space between the coating and the substrate.

The object of the invention is to eliminate the above-mentioned drawbacks and to provide a composite felt which, in terms of both surface properties and material choices, is particularly suitable for many applications. It is also an object of the invention to provide a method of making such a felt.

The body layer of the composite felt consists mostly of mineral staple fibers and is topped with a surface layer containing heat-bonded fibers. The surface layer is quite thin, 0.5-1 mm, and consists either entirely of staple fibers, hereinafter referred to as binder fibers, 4 85032 which, due to heat treatment, have partially fused and bonded the fibers together. The heat treatment is preferably carried out at a temperature of 100-200 ° C. This surface layer may comprise at least two materials melting at different temperatures 5, whereby by melting the fibers of the second one completely by heat treatment, the fibrous structure remains in the surface layer due to the higher melting fibers.

One advantage of the invention when coating a composite-10 felt with a resin is that the coating layer and the load-bearing body layer must not interact directly with each other. This is because the paste would then be absorbed quite deep into the body layer, causing the properties of the layer to change unevenly, and thus could not be easily controlled to find a favorable optimum state. In this case, perhaps less desirable qualitative throws should be accepted, or at least the fact that the product requires funds and resources only and specifically to achieve consistent quality. 20 In addition, the sales of pasta are quite high due to the open fiber structure compared to the use for which it is intended.

The purpose of the surface layer according to the invention is e.g. to provide a strong adhesion of the coating layer to the run-25 whole layer without the paste forming the coating layer penetrating the body layer. This is achieved according to the invention in that the surface layer acts as a bonding layer between the coating and the body layer. Since there are 30 heat-bondable fibers in the surface layer, they also adhere firmly to the coating layer due to the hot coating paste. If there are two different fibrous materials in the surface layer with different melting points, the fibers of the higher melting material can first be bonded together so that the lower melting material is allowed to melt in the heat treatment. The coating with the coating layer on top of the composite felt can then be done at a higher melting temperature of the fusible material.

In the manufacture of the composite felt, the binder fibers of the surface layer are impregnated into its surface by means of an air flow during the manufacture of the body layer and fixed to it by needling. By selecting the components of the surface layer as needed, the adhesive properties can be controlled over a wide range without side effects on the other properties of the body layer. The bonding fibers of the surface layer may comprise, for example, polyethylene, which melts at a temperature of about 100 ° C, and polyester, which melts at a temperature of about 200 ° C. Other combinations of substances are also possible, such as polyethylene-polypropylene or polypropylene-polyester. Em. substances also mean copolymers thereof, i.e. polymers having their monomer units, or also derivatives thereof, i.e. polymers having bonds between the carbon backbone of the base polymer and the monomer units, but different side groups.

The composite felt according to the invention offers versatile uses as part of different construction materials. For example, the coating paste applied at a later stage cannot penetrate the actual body layer, which can be any felt structure comprising mineral fibers. The properties of the body layer can thus be optimized quite precisely to the desired quality in the manufacture of the composite felt, knowing that they will not change at a later stage due to the other material applied to the felt.

6 85032

Facing the decorative layer, the surface of the surface layer is so smooth due to the post-knitting heat treatment that it has no protruding fibers. However, its porosity can be controlled in a controlled manner by selecting the fiber grades and heat treatment as needed to provide the paste with a good adhesion surface. The adhesion is also promoted by chemical bonding, which can be achieved by treating the surface, if necessary, by methods known per se.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 shows in cross-section and on an enlarged scale a structural element using a composite felt according to the invention and Figure 2 schematically shows a side production line for producing a composite felt.

Reference numeral 1 denotes in the figure a body layer known per se, which is of the nonwoven type and consists of mineral fibers such as lining, glass, slag, ceramic, carbon, etc. staple fibers. Due to the good adhesion obtained according to the invention, the weight of the body layer can be very high, such as 2000 g / m 2. However, the basis weight of the body layer can vary within wide limits, e.g. 80-2000 g / m 2. The length of the fibers of the body layer is for the most part in the range of 1-20 mm, preferably in the range of 4-10 mm. In the case of glass fibers and carbon fibers, the above values may be higher.

7 85032

Reference numeral 2 denotes a surface layer according to the invention comprising heat-bonded synthetic staple fibers. Reference numeral 3 schematically indicates those staple fibers of the surface layer which, due to the knitting, enter transversely into the body layer 1 and some of which protrude on the opposite side of the body layer. Reference numeral 4 denotes a coating paste applied on the surface layer 2, for example to provide a PVC mat or, in its general form, the placement of a separate layer in a composite felt sandwich structure. Such a layer can be any brushable curable paste which binds to the surface layer 2 by heat and / or chemical bonding.

The amount of heat-bondable binder fibers in the surface layer 2 may be 10-100% by weight of the total amount of fibers in the layer. The preferred range has been found to be 20-40% by weight. The weight of the surface layer can vary between 10 and 100 g / m 2, and the length and thickness of the fibers between 2 and 30 mm, respectively, between 4 and 30 μιη. The other fibers of the surface layer may be non-thermally bonded fibers, such as non-thermally bonded synthetic fiber.

Figure 2 shows a production line for the production of a composite felt according to the invention. 25 of the support layer 1 consisting of mineral staple fibers are optionally doped with other fibers fed from the direction of the arrow A, with holes equipped with a transport belt 15. The fibers have been previously known per se, very fast rotating spike roll 30 from each other, separated by a flow of air through the belt 15. At this stage the mat on the belt 15 of the is a bit wavy.

8 85032

The conveyor belt 15 advances the nonwoven to a point 16 where the nonwoven comes under a vertical air duct 17 above the conveyor. The air channel air is blown in the direction of arrow B in downward direction so that the air passes through 5 marked by broken lines in FIG fiber mat and the conveyor 15 and continue their journey along a conveyor arranged below the channel. At the same time, the nonwoven mat is compressed against the conveyor 15, which is illustrated by the broken lines. The inlet of the conveyor in the direction between the front wall of the air duct 17 and the conveyor 15 is a gap from which the thick nonwoven mat enters the air duct, and the duct rear wall at the point where the compressed nonwoven exits the duct 17 has a roll 18. The fibers forming the surface layer 2 according to the invention are fed into the air duct 17 above the point where the nonwoven mat enters the duct 17, and the feed takes place obliquely downwards along the duct 19 connected to the duct 17. The fibers are fed into the duct 19 by means of a rapidly rotating small roll which separates the fibers from each other and throws them into the duct 19, from which the air flow of the air duct 17 takes them with it and presses them onto the rest of the nonwoven. Thus, a thin fiber layer 2 with a flat surface is caused to form on the body layer 1 already at this stage m.m. due to the fact that the less fibrous points in the body layer 1 are more permeable to air, where more surface layer fibers naturally accumulate at these points with the air flow B.

After the conveyor 15, the composite felt thus obtained is passed to a needling, where mechanically piercing the needles causes a part of the surface layer 2 fibers 9 85032 to be directed to the body layer 1, thereby mechanically binding the surface layer 2 fibers to the body layer 1. Depending on the thickness and length of also on the other side, whereby a fluff-like structure is obtained on the back side due to the protruding surface layer fibers. Spike rolls as well as needling are previously known in fiber technology and are therefore not shown in more detail.

After needling, the fibers of the surface layer can be bonded together by heat treatment, e.g., using temperatures in the range of 100-200 ° C depending on the materials of the surface layer. Previously known heat treatment devices can be used in the method.

The fiber feed rate as well as the air flow rate B can, of course, affect the basis weight and density of the nonwoven. In general, the use of rapidly rotating spike rollers, which effectively separate the fibers from each other, provides a more fluffy and bulky structure for the resulting mat, in which the fibers are more oriented in arbitrary directions.

After the heat treatment, the mat can be wrapped 25, e.g. on a roll, and can be used as a raw material in the above-mentioned structural elements.

10 85032

Example

A felt forming the body layer 1 with a final thickness of about 3 mm was made of rock wool fibers with a length of less than 5 mm and a thickness of 6. The fibers were collected into a felt so that they were randomly oriented and the weight of this layer was about 600 g / m 2.

The upper surface of this body layer was impregnated with an air stream to a surface layer about 0.5 mm thick, consisting of polyester fibers and polyethylene fibers 10 with a length of about 20 mm and a thickness of about 20. The weight of the surface layer was estimated to be about 100 g / m 2, and it was attached to the body layer by needling. After attachment, the bonding layer was heat treated at about 100 ° C to provide a final composite felt, whereupon the polyethylene fibers melted and glued the polyester fibers together.

After the heat treatment, the bonding layer was visible on the surface of the body layer as a lighter layer about 1 mm thick, i.e. against 20 brownish tones of rock wool fibers. The bonding layer could not be separated from the body layer by pulling, but the entire composite felt disintegrates.

A layer of PVC paste with a final thickness of about 1 25 mm was applied to the composite felt as a coating layer. At the same time, the molten paste layer caused the polyester fibers to melt, whereby the coating layer adhered firmly to the surface layer. The composite felt cannot be separated by pulling from this surface either, but the whole composite felt breaks down.

11 85032

The structural element according to the invention has been found to have good dimensional stability and step sound attenuation.

The invention is not limited only to the embodiment shown in the example above, but can be varied within the scope of the inventive idea set forth in the claims. For example, the body layer 1 may, in addition to the mineral fibers, also comprise other fibers, e.g. heat-binding synthetic fibers, if it is desired to be stiffer than the body layer. However, the proportion of Mine-10 raw fibers should be at least 50% by weight of the total weight of the backing layer.

Claims (7)

Combination felt, in which there are at least two fiber layers of different materials, characterized in that the base layer (1) consists mostly of discontinuous mineral fibers and over this there is a surface layer (2) containing heat-bondable fibers. Combination felt according to claim 1, characterized in that the heat-bondable fibers of the surface layer (2) comprise at least two fibrous materials having different melting points. Combination blanket according to claim 2, characterized in that the material having different melting points in the surface layer is of thermoplastic plastic. Combination blanket according to claim 3, characterized in that the material melting at a lower temperature is polyethylene or polypropylene and the material melting at a higher temperature is polypropylene or polyester, the aforementioned materials being included in the alternatives as well. their copolymers and derivatives. 25 Combination blanket according to any of claims 1-4, characterized in that the surface layer (2) is mechanically bonded to the base layer (1) by grinding. 30 6. A method for making a combination blanket, wherein a method comprising a surface layer of fibers is applied to a base layer of fibers, - characterized in that the base layer (1) is formed from discontinuous mineral fibers by bringing them by means of a air flow on a conveyor (15), whereby a heat-bondable fiber containing layer (2) is brought onto the base layer (1) by passing said fibers on the layer with the air flow which is simultaneously allowed to pass through the genoxn base layer (1), after which the surface layer (2) ) fibers are bonded to each other in a heat treatment. 5 7. A method according to claim 6, characterized in that the surface layer (2) is bonded to the base layer (1) xnechanically by kneading before the heat treatment. 10