Process and plant for obtaining a composite panel of natural stone and glass and associated product

Abstract

In a process for obtaining a composite panel of natural stone and glass, after preparing a slab of natural stone ( 10 ) and a glass sheet ( 20 ), a layer of hardening resin ( 32 ) is spread over a surface (1 0 a ) of the stone slab ( 10 ), the glass sheet ( 20 ) is arranged on top of said stone slab ( 10 ) inside an environment under vacuum conditions so as to allow the layer ( 32 ) of resin which is situated in between to harden completely. The process may be continued by applying a second glass sheet ( 24 ) onto the other surface ( 10 b ) of the stone slab ( 10 ) using the same procedure and by finally cutting the panel thus formed ( 50 ) along the mid plane so as to obtain two panels, each of which comprises a stone slab ( 10 ) and a glass sheet ( 20, 24 ).

1 . Process for obtaining a composite panel comprising a slab of natural stone ( 10 ) joined to a glass sheet or pane ( 20 ), which envisages the following steps: 
 a) preparation of a slab of natural stone ( 10 );    b) preparation of a glass sheet or pane ( 20 );    c) spreading a layer of hardening resin ( 32 ) over a surface either of said stone slab ( 10 ) or of said glass sheet ( 20 );    d) joining the sheet or slab without resin to the slab ( 10 ) or sheet ( 20 ), over a surface of which the resin ( 32 ) has been spread, so that said layer ( 32 ) of hardening resin is situated between the stone slab ( 10 ) and the glass sheet ( 20 ); and    e) hardening of the resin ( 32 ),    wherein the step d) of joining together the slab and the sheet ( 10 ,  20 ) is performed in an environment under vacuum conditions, so as to eliminate the risk of air being trapped and thus ensuring perfect bonding between the slab and sheet ( 10 ,  20 ) to be joined together.    
     
     
         2 . Process according to  claim 1 , wherein before arranging the slab and sheet ( 10 , 20 ) on top of each other, spacer elements ( 34 ) are provided so as to keep the slab and sheet ( 10 , 20 ) to be joined at a distance from each other, said spacer elements ( 34 ) being later removed in said environment under vacuum conditions, so as to cause the slab and sheet ( 10 ,  20 ) to come into contact with each other and thus ensure a complete elimination of the air in the joining zone between the slab and sheet ( 10 ,  20 ).  
     
     
         3 . Process according to  claim 1 , wherein the layer ( 32 ) of hardening resin is spread over one surface ( 10   a ) of the stone slab ( 10 ) and the glass sheet ( 20 ) is arranged on top of the slab of natural stone ( 10 ).  
     
     
         4 . Process according to  claim 1 , further comprising the following steps: 
 f) spreading a layer ( 32 ) of resin over the surface ( 10   b ) of the stone slab ( 10 ) not joined to the glass sheet ( 20 );    g) joining a second glass sheet or panel ( 24 ) onto the stone slab ( 10 ) in an environment under vacuum conditions;    h) hardening of the resin ( 32 ); and    i) performing a cut along the mid plane of the thickness of the panel ( 50 ) thus formed as to obtain two panels ( 60 ), each of the said panels ( 60 ) being formed by a stone slab ( 10 ) joined to a glass sheet ( 20 ,  24 ).    
     
     
         5 . Process according to  claim 1 , wherein during step a), the surfaces ( 10   a , 10   b ) of the stone slab ( 10 ) to be joined to the glass sheet ( 20 ) are leveled so as to reduce the thickness of the resin layer ( 32 ) used and to ensure better bonding between the slab and sheet ( 10 ,  20 ) to be joined together.  
     
     
         6 . Process according to  claim 5 , wherein during step a), after leveling the surfaces ( 10   a , 10   b ) of the stone slab ( 10 ) and before step c) for spreading the resin ( 32 ), the stone slab ( 10 ) is dried so as to eliminate any residual water.  
     
     
         7 . Process according to  claim 6 , wherein after leveling and also before step f), the stone slab ( 10 ) is heated so as to accelerate hardening of the resin ( 32 ).  
     
     
         8 . Process according to  claim 1 , wherein during step e), the degree of vacuum created has a value not greater than 30 mm Hg residual pressure.  
     
     
         9 . Process according to  claim 1 , wherein said glass sheet or panel ( 20 ,  24 ) to be joined to a stone slab ( 10 ) consists of stratified glass.  
     
     
         10 . Process according to  claim 9 , characterized in that the stratified glass ( 20 , 24 ) comprises at least two single sheets of glass ( 20   a ,  20   b ) which are bonded to one another by means of an intermediate layer of polymer ( 22 ) opaque to ultraviolet rays.  
     
     
         11 . Process according to  claim 1 , wherein the surface of said glass sheet or pane ( 20 ,  24 ) to be joined to said stone slab ( 10 ) is roughened so as to improve the adhesion between the said slab and sheet ( 10 ,  24 ) to be joined together.  
     
     
         12 . Process according to  claim 11 , wherein surface of said glass sheet or panel ( 20 ,  24 ) is roughened by means of sandblasting.  
     
     
         13 . Process according to  claim 1 , wherein said hardening resin is an epoxy resin.  
     
     
         14 . Process according to  claim 1 , wherein: 
 a sandwich assembly is prepared, said assembly consisting of a stone slab ( 10 ) having a layer of resin ( 32 ) spread over one ( 10   a ) of its surfaces and of a glass sheet or pane ( 20 ) lying on removable spacer supports ( 34 ) arranged between the facing surfaces ( 10   a ,  20   a ) of the said slab and sheet ( 10 , 20 ) and being such as to keep the latter at a predetermined distance;    said sandwich assembly is introduced into said environment under predetermined vacuum conditions, and    finally said spacer supports ( 34 ) are removed so that said glass sheet ( 20 ) rests on the surface ( 10   a ) of said stone slab ( 10 ) provided with the layer of hardening resin.    
     
     
         15 . Process according to  claim 14 , wherein said spacer supports ( 34 ) are arranged along two longitudinal edges of said slab and sheet ( 10 ,  20 ).  
     
     
         16 . Plant for the production of a composite panel, comprising: 
 a station ( 52 ) where a sandwich assembly is obtained which comprises a slab of natural stone ( 10 ), a glass sheet or panel ( 20 ) and a layer ( 32 ) of hardening resin applied onto a surface either of said slab or of said sheet ( 10 ,  20 ) and    a subsequent station ( 58 ) for hardening the resin, and    an intermediate station ( 54 ) which is able to keep the said sandwich assembly under vacuum conditions for the whole of the time during which the facing surfaces ( 10   a ,  20   a ) of the said slab and sheet ( 10 ,  20 ) between which the said layer of hardening resin ( 32 ) is situated are moved towards each other and brought into full contact.    
     
     
         17 . Plant according to  claim 16 , wherein said intermediate station ( 54 ) comprises a bed ( 62 ) and a sealable bell ( 64 ) which can be lifted and is connected to a vacuum pump ( 66 ), the said pump starting to function after the said bell ( 64 ) has been brought from a raised position, in which said sandwich assembly is allowed to enter, into a lowered operative position.  
     
     
         18 . Plant according to  claim 16 , wherein said sandwich assembly also comprises spacer elements ( 34 ) able to keep the facing surfaces ( 10   a , 20   a ) of said slab and sheet ( 10 , 20 ) at a predetermined distance and in that said intermediate station ( 54 ) also comprises means ( 72 ) for removing said spacer elements ( 34 ).  
     
     
         19 . Composite panel of natural stone and glass made in accordance with the process of  claim 1.