Abstract:
An insulation material and method for producing it. A basic material is built up of cells and a filler which is present in the cells. The filler is built up of separate fibers which are bonded together by means of a foam-like bonding agent. The filler is introduced into the open cells of the basic material. A mixture of separate fibers and a foam-like bonding agent is prepared and the mixture is introduced into the open cells by way of a nozzle.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an insulation material comprising a basic material which is built up of cells and a filler which is present in said cells. 
     The invention furthermore relates to a method for producing such insulation material and to a device for carrying out the method in order to obtain the intended insulation material. 
     2. Discussion of the Background 
     From U.S. Pat. No. 4,271,876 it is known to use insulation material comprising a basic material built up of cells for producing prefabricated building components. The thermal and acoustic insulation value of such building components incorporating basic materials built up of cells can be further enhanced, however. The improvement of the thermal and acoustic insulation of such insulation material may take place by filling the cells with a filler of for example mineral wool fibres or cellulose fibres. 
     The term fibres used herein is understood to mean short, elongated particles, but also granular particles and the like. 
     Several experiments have been conducted within this framework, but it has become apparent that it is very difficult to fill the cells properly with such relatively light fibres. As a result of the problems involved in the filling of such basic material the use of this insulation material has not led to the expected large-scale use, because the increasingly stringent requirements with regard to the insulation value are not met. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide an insulation material whereby fibres have been introduced into the cells of the basic material in a simple manner. 
     This objective is accomplished with the basic material according to the invention in that said filler is built up of separate fibres, which are bonded together by means of a foam-like bonding agent. 
     The foam will make the fibres heavier, as a result of which the fibres can be introduced into the cells of the basic material by the force of gravity. Fibres not bonded to bonding agent are relatively too light, and they exhibit a tendency to remain on top of the basic material. 
     A major advantage of the insulation material according to the invention is the fact that it has a high insulation value and that the filler can be introduced into the cells in a simple manner. 
     It has to be noted that from WO 93/25492 an isulation material is known comprising fibres which are bonded together by means of a foamlike bonding agent. However, this insulation material is used as such. 
     Another object of the invention is to provide a method wherein fibres can be introduced into the cells of the basic material in a simple manner. 
     This objective is accomplished with the method according to the invention in that first a mixture of separate fibres and a foam-like bonding agent is prepared, and that this mixture is introduced into the open cells of the basic material via a nozzle. 
     The fibres, which are weighted and bonded by the foam, can be introduced into the cells of the basic material in a simple manner, for example under the influence of the force of gravity. 
     One embodiment of the method according to the invention is characterized in that said filler is defibered into fibres, the fibres are subsequently bonded together by means of the bonding agent, after which the bonded fibres are defibered anew and introduced into the cells of the basic material. 
     By defibering the filler relatively small fibres or separate particles will be obtained. Said fibres are subsequently bonded to the bonding agent, as a result of which the specific weight of each fibre will increase. The fibres will also adhere together as a result of the presence of the bonding agent. When subsequently the fibres provided with the bonding agent are defibered, fibres weighted by the bonding agent will be obtained, which will fall into the cells of the basic material under the influence of the force of gravity. It is also possible, of course, to blow or suck the fibres into the cells of the basic material. 
     One embodiment of the method according to the invention is characterized in that upon providing the fibres with the bonding agent, the fibres are formed into a foam by means of the bonding agent, which foam is subsequently defibered. 
     Defibering the foam will result in the formation of separate fibres surrounded by bonding agent, which can be introduced into the cells of the basic material in a simple manner. The fibres will adhere together again once they are in the cell, to which adhering process the bonding agent will be conducive. 
     Another embodiment of the method according to the invention is characterized in that the basic material is vibrated while the fibres are being introduced into the cells. 
     The vibration of the basic material will cause the particles being introduced into the cells to move downward, thus creating space for additional fibres near the upper side of the cells. In this manner the cells will be entirely filled with fibres. 
     The invention also relates to a device suitable for carrying out the method, which comprises a filling station, which device is characterized in that said filling station is provided with a mixer for mixing said bonding agent and said fibres, so as to obtain said filler. 
     The fibres are bonded to the bonding agent by means of such a device before being introduced into the cells of the basic material. 
     One embodiment of the device according to the invention is characterized in that the device comprises a first defibering apparatus, a mixer connected to said first defibering apparatus via a pipe, which mixer is connected, via a further pipe, to a second defibering apparatus, which is provided with an outlet opening. 
     With such a device the first defibering apparatus is used for reducing the insulation material to fibres. The second defibering apparatus is used for separating the fibres, which adhere together as a result of the presence of the bonding agent. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in more detail with reference to the drawing, in which: 
     FIG. 1 is a longitudinal sectional view of a device according to the invention; and 
     FIG. 2 shows another device according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a device  1  comprising a first defibering apparatus  2 , a mixer  4 , which is connected to defibering apparatus  2  via a flexible pipe  3 , a second defibering apparatus  6 , which is connected to mixer  4  via a flexible pipe  5 , and a conveyor  7 , which is disposed under defibering apparatus  6 . 
     Defibering apparatus  2  is provided with an inlet channel  8 , under which three rotatable rollers  9 ,  10 ,  11  fitted with wire brushes are disposed. Roller  9  abuts against roller  11 . A feeding gap  12  is present between rollers  9 ,  10 . Roller  9  is driven in clockwise direction, as indicated by arrow P 1 , whilst rollers  10 ,  11  are driven in anti-clockwise direction, as indicated by arrows P 2 , P 3 . The speeds at which rollers  9 ,  11  are driven in the direction indicated by arrow P 1 , P 3  and the pressure with which roller  9  is driven against roller  11  can be adjusted and varied. 
     Defibering apparatus  2  is provided with a passage  13  under rollers  9 ,  10 ,  11 , which passage opens into a space  14 . Present in space  14  is a blade wheel  16 , which bears on a shaft  15  and by means of which fibres coming from passage  13  are transported. Disposed under space  14  is a dividing apparatus  17 , which is provided with a number of rods  18  coupled to a central shaft, which rods extend between fixedly disposed rods  20 . Disposed under apparatus  17  is a dividing station  19 . An air blowing unit  21 , which is driven by means of a motor, is connected to dividing station  19  via a pipe  20 . Dividing station  19  is connected to mixer  4  via flexible pipe  3 . Mixer  4  is furthermore provided with a supply pipe  22  for compressed air and with a supply pipe  23  for a bonding agent. Mixer  4  is connected to a second defibering apparatus  6  via a pipe  5 . Defibering apparatus  6  comprises a blade wheel  25  near an upper side, which is rotatable about a shaft  24 , and rollers  26 ,  27 ,  28 , which are disposed under blade wheel  25 . Rollers  26 ,  28 , which are provided with wire brushes, abut against one another. A gap  29  is present between roller  26  and roller  27 . Rollers  26 ,  28 ,  28  are rotatable in directions indicated by arrows P 4 , P 5  and P 6  respectively. An outlet opening  30 , which opens above conveyor  7 , is present under rollers  26 ,  27 ,  28 . Conveyor  7  is provided with a conveyor belt  31 , a number of vibrating devices  32  disposed under conveyor belt  31 , and a number of brushes  33 ,  34 ,  35 , which are disposed an adjustable distance above conveyor belt  31 . Conveyor  7  is furthermore provided with a strickling brush  36 . Vibrating devices  32  are each provided with a vibrating plate  37 , which is reciprocated in the directions indicated by double arrows P 7 , P 8  by means of a drive unit  38 . Plate-shaped material  39  comprising a plurality of cells  40  is present on conveyor belt  31 . Cells  40  form a honeycomb structure in plate  39 . Brushes  33 ,  34  are rotatable about an axis extending transversely to the plane of the drawing. Brush  35  is rotatable about an axis including an acute angle with the plane of the drawing. 
     The operation of device  1  will now be briefly explained. Relatively large pieces of filler, for example in the shape of plates or pieces, are supplied to defibering apparatus  2  in the direction indicated by arrow P 9  via inlet opening  8 . Said filler is pulled into gap  12  by rollers  9 ,  10 , from where the filler is pulled between rollers  9 ,  11  and transported in the direction of passage  13 . Rollers  9 ,  11  are driven at different speeds, as a result of which the filler is pulled apart into fibres. Fibres  41  whirl into space  14  and are transported in the direction indicated by arrow P 10  by means of rotating blade wheel  16 . Then the fibres are grabbed by the rods  18  of device  17 , which rotate about the shaft, and carried into device  19 . The filler being introduced into inlet  8  is pulled completely apart by rollers  9 ,  11 , blade wheel  16  and rotating rods  18 , and divided into relatively small fibres. Air blowing device  21  blows air into device  19  via pipe  20 , as a result of which the fibres present in the device  19  are carried into pipe  3 . The fibres are blown further apart by the air flow. The fibres are transported through pipe  3  in the direction indicated by arrow P 11 , to mixer  4 . Compressed air and a bonding agent are supplied to mixer  4  via pipe  22  and pipe  23  respectively, as a result of which the fibres present in mixer  4  are efficiently bonded to the bonding agent. The fibres, which are bonded to the bonding agent and which are provided with bonding agent are blown in the direction indicated by arrow P 12  into pipe  5  by the air flow produced by device  21 , from where the fibres provided with bonding agent, which adhere together by now, are carried into defibering apparatus  6 . The bonded-together fibres are pulled slightly apart by the blade wheel  25  rotating about shaft  24 . Then the fibres are passed in the gap  29  between rollers  26 ,  27  in the direction indicated by arrow P 13 . Rollers  26 ,  28  are driven at different, variable speeds, as a result of which the bonded-together fibres are pulled apart and carried in the direction indicated by arrow P 14  towards outlet  30 . Outlet  30  is located above the plate  39  comprising cells  40 , and the fibres provided with bonding agent, which have been separated from each other by defibering apparatus  6 , will fall into cells  40  under the influence of the force of gravity. Base plate  39  is vibrated to and fro by means of vibrating devices  32  disposed under conveyor belt  31 , as a result of which the fibres falling into cells  40  will move further in downward direction. The fibres falling onto plate  38  are swept into cells  40  by means of brush  36 , which is driven in the directions indicated by double arrow P 15  and in directions extending transversely thereto. 
     During the filling of cells  40  base plate  39  is slowly moved in the direction indicated by arrow P 16  by means of conveyor belt  31 . During said movement the fibres still present on plate  39  are swept into cells  40  by brushes  33 ,  34 . Any fibres remaining on the plate are swept off said plate by brush  35 , which is disposed at an angle with respect to brushes  33 ,  34 . 
     FIG. 2 diagrammatically shows another device for producing the insulation material according to the invention. 
     FIG. 2 shows filling station  41  comprising a mixing head  42 , in which the filler is mixed by supplying the mineral wool fibres or the cellulose fibres as well as the bonding agent. Following the mixing step the foam thus formed is introduced into cells  45  of honeycomb  44  via outlet  43 . Filling station  41  is furthermore provided with a strickle  46 , so that excess foam-like filler is removed and transferred to incompletely filled cells. The filled cells  47  contain a filler, which is dried, if necessary, so that the fibres are surrounded by cured foam, resulting in a cohesion between the individual fibres mutually and an adherence to the cell surfaces. Thus the cells are filled with an insulating filler. 
     In order to promote the evacuation of the air from the honeycomb structure  44 , an air exhaust channel  48  is provided at the bottom side, by means of which air is exhausted, without any filler being carried along. The honeycomb is passed under the filling station in the direction indicated by arrow  49 , whereby the combs are gradually filled with foam consisting of said material mixed with the separate particles, so that a honeycomb structure filled with a filler is formed, as a result of which the insulation value is enhanced in comparison with the honeycomb structure which is not filled with a filler. 
     Any material with which the individual fibres can easily be weighted may be used as the bonding agent. The fibres may first be moisturized and weighted by means of the bonding agent and subsequently be bonded together and dried in the cells.