CA2357009C - Rubber sheet structure for use in the production of slabs of granulate or fine particles of stone material bonded with hardening resin - Google Patents
Rubber sheet structure for use in the production of slabs of granulate or fine particles of stone material bonded with hardening resin Download PDFInfo
- Publication number
- CA2357009C CA2357009C CA002357009A CA2357009A CA2357009C CA 2357009 C CA2357009 C CA 2357009C CA 002357009 A CA002357009 A CA 002357009A CA 2357009 A CA2357009 A CA 2357009A CA 2357009 C CA2357009 C CA 2357009C
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- rubber
- layer
- cloth
- composite structure
- shaped sheet
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B25/00—Layered products comprising a layer of natural or synthetic rubber
- B32B25/10—Layered products comprising a layer of natural or synthetic rubber next to a fibrous or filamentary layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B7/00—Moulds; Cores; Mandrels
- B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials
- B28B7/348—Moulds, cores, or mandrels of special material, e.g. destructible materials of plastic material or rubber
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
- B29C67/24—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/02—Synthetic macromolecular fibres
- B32B2262/0261—Polyamide fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/02—Synthetic macromolecular fibres
- B32B2262/0276—Polyester fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
- B32B2307/734—Dimensional stability
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
- B32B2309/02—Temperature
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
- B32B2309/04—Time
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2319/00—Synthetic rubber
Abstract
Two rubber sheets are used in the production of slabs of granulate or fine particles of stone material bonded with hardening resin, one of said sheets, the lower one, being provided with a border delimiting the cavity for deposition of a metered quantity of mixture. At least the lower sheet and preferably both sheets have a structure consisting of two layers of EPM or VKF or PU rubber between which a layer of fabric or cloth of non-deformable material, such as polyamide or polyester, is interposed or inset and the outwardly directed surface of the sheet is composed of a similar layer of fabric or cloth.
The composite sheet can be stabilized dimensionally by means of heat treatment at a temperature higher than the operating temperature.
The composite sheet can be stabilized dimensionally by means of heat treatment at a temperature higher than the operating temperature.
Description
:Etubber sheet structure for use in the production of slabs of granulate or fine particles of stone material bonded with hardening resin.
*****
The present invention relates to the production of manufactured slabs composed of a granulate or fine particles of stone materical bonded with a hardening resin and, more speciScally, to an improvement to the production process therefor.
These slabs are produced using a method in which a mixture composed of granulate matenal of selected particle size and synthetic resin is deposited in metered quantities on a conveyor belt which is advanced to a forming station (in which it is subjected ta a vacuum compaction operation with simailtaneous application of a vibratory movement of pr.edeteimined frequency) and subsequently to a station for hardening of the resin (preferably by means of the action of a catalyst and/or heat).
Upstream of the forming station, the upper surface of the mixtm deposited on the conveyor belt is covered with a sheet or layer of protective materiai, wluch prevents the pressing ram from being soiled by the mixture.
In the past, this sheet of protective material was made of paper, the use of which, however, was accompanied by cmtain secondary problems subsequent to the actuai production process, but nonetheless of considerable importance.
An improvement was subsequently introduced (described and claiimed in Italian patent appfication No. TV96A!O00007 filed on 29 January 1996), according to which the paper layer or sheet is replaced by a sheet of resilient material, pre&rably rubber.
In this way, upon completion of the resinous binder hardening step, the rubber sheet can be removed, by means of tearing, from the surface of the finished slab and subsequently reused.
In the preferred embodiment, the support on which the mixture is deposited before being transferred to the vacawm and vibration compacting station is also protected by a simdar sheet of resilient material, in particular rubber.
After the forming step, the mixfure deposited on the support and enclosed between the two rubber sheets is in the form of a slab, at the edges of which the two protective rubber sheets are joined together by overlapping their respective edges, substantially completely so as to enclose the raw slab which has been formed but not yet subjected to the resinous binder hardening step.
Since during compaction a portion of the mixture, albeit minimal, inevitably forms a burr interposed between the two edges, after the resinous binder hardening step this burr forms incrustations on the rubber sheets, which are difficult to remove.
Again in the previously know method, a separating liquid is applied to the two edges which are intended to mate, immediately before use on the production line, with the purpose of preventing this problem and also of reducing the chemical ageing of the rubber.
In spite of these measures, however, operations to clean the two rubber sheets, and in particular the two mating edges, are stiil necessary.
U.S.Patent 6,773,641 in the name of the same Applicant describes further improvements aimed at preventing the formation of incrustations on the rubber sheets, which require laborious cleaning operations, and involving modifications both to the shaping of the protective rubber sheets and to the operating process.
In the first place, the flat configur-ation of the lower sheet is replaced by a shaped configuration, comprising a flat base and a peripheral border projecting from said flat base over a predetermined height which is smaller by a predetermined amount than the height of the final slab to be produced, so that, after the compaction step, a gap of a pr.edetermined thickness remains between the peripheral edge of the upper sheet and the top of the aforementioned border.
The excess mixture material penetrates into this gap.of predetermined thickness during the vacuum vibrati'on compacting step and this material then remains attached to the edge of the slab during the hardening step., When, after the resinous binder hardening step, the final slab is released by tearing off the two rubber sheets, a hardened raw slab is obtained, said slab having periphezally a border of 2.5 hardened material which can easily be removed during the normal finishing operations for a slab of stone material.
U.S. Patent 6,773,641 also describes and claims a specific structure of the rubber sheet, in particular the lower sheet, to which the peripheral border is attached, said border defining the cavity for initial deposition of the metered quantity of mixture.
*****
The present invention relates to the production of manufactured slabs composed of a granulate or fine particles of stone materical bonded with a hardening resin and, more speciScally, to an improvement to the production process therefor.
These slabs are produced using a method in which a mixture composed of granulate matenal of selected particle size and synthetic resin is deposited in metered quantities on a conveyor belt which is advanced to a forming station (in which it is subjected ta a vacuum compaction operation with simailtaneous application of a vibratory movement of pr.edeteimined frequency) and subsequently to a station for hardening of the resin (preferably by means of the action of a catalyst and/or heat).
Upstream of the forming station, the upper surface of the mixtm deposited on the conveyor belt is covered with a sheet or layer of protective materiai, wluch prevents the pressing ram from being soiled by the mixture.
In the past, this sheet of protective material was made of paper, the use of which, however, was accompanied by cmtain secondary problems subsequent to the actuai production process, but nonetheless of considerable importance.
An improvement was subsequently introduced (described and claiimed in Italian patent appfication No. TV96A!O00007 filed on 29 January 1996), according to which the paper layer or sheet is replaced by a sheet of resilient material, pre&rably rubber.
In this way, upon completion of the resinous binder hardening step, the rubber sheet can be removed, by means of tearing, from the surface of the finished slab and subsequently reused.
In the preferred embodiment, the support on which the mixture is deposited before being transferred to the vacawm and vibration compacting station is also protected by a simdar sheet of resilient material, in particular rubber.
After the forming step, the mixfure deposited on the support and enclosed between the two rubber sheets is in the form of a slab, at the edges of which the two protective rubber sheets are joined together by overlapping their respective edges, substantially completely so as to enclose the raw slab which has been formed but not yet subjected to the resinous binder hardening step.
Since during compaction a portion of the mixture, albeit minimal, inevitably forms a burr interposed between the two edges, after the resinous binder hardening step this burr forms incrustations on the rubber sheets, which are difficult to remove.
Again in the previously know method, a separating liquid is applied to the two edges which are intended to mate, immediately before use on the production line, with the purpose of preventing this problem and also of reducing the chemical ageing of the rubber.
In spite of these measures, however, operations to clean the two rubber sheets, and in particular the two mating edges, are stiil necessary.
U.S.Patent 6,773,641 in the name of the same Applicant describes further improvements aimed at preventing the formation of incrustations on the rubber sheets, which require laborious cleaning operations, and involving modifications both to the shaping of the protective rubber sheets and to the operating process.
In the first place, the flat configur-ation of the lower sheet is replaced by a shaped configuration, comprising a flat base and a peripheral border projecting from said flat base over a predetermined height which is smaller by a predetermined amount than the height of the final slab to be produced, so that, after the compaction step, a gap of a pr.edetermined thickness remains between the peripheral edge of the upper sheet and the top of the aforementioned border.
The excess mixture material penetrates into this gap.of predetermined thickness during the vacuum vibrati'on compacting step and this material then remains attached to the edge of the slab during the hardening step., When, after the resinous binder hardening step, the final slab is released by tearing off the two rubber sheets, a hardened raw slab is obtained, said slab having periphezally a border of 2.5 hardened material which can easily be removed during the normal finishing operations for a slab of stone material.
U.S. Patent 6,773,641 also describes and claims a specific structure of the rubber sheet, in particular the lower sheet, to which the peripheral border is attached, said border defining the cavity for initial deposition of the metered quantity of mixture.
The said structure consists of two or more layers, usually four layers, such as:
a first layer of rubber (VRF, EPM, PU) TM
a first cloth or fabric of non-deformable material (Kevlar, polyester, nylon, aranvde) a second layer of rubber (EPM, NBR (Nitrile Butadiene Rubber)) a second cloth or fabric of non-deformable material.
Preferably this cloth or fabric is subjected to preliminary treatments, such as a pretensioning treatment, to avoid subsequent hysteresis phenomena, a theimal stabilization, etc.
However, certain requirements remain in connection with the rubber sheets and must be satisfied in order to obtain optimum results.
In sbort, these requirements correspond to the following characteristics which the rubber sheet nnist have:
a resistance to beat and chemical agents so as to withstand operating temperatures which during the resi*i hardening step are in the region of 150 C;
a good resistance to abrasion and tearing;
(c) retain substantially unaltered properties over time;
(d) possess optimal mechanical properties so as to contain the mixture without undergoing excessive deformations;
(e) undergo minimal shrinkage after forming so as to prevent the formation of surface irregularities in the final product; and (f) a good heat conductivity in order to favour the hardening of the slab.
- As regards the nature of the rubber, the most suitable are of a polymeric type resistant to temperature and to chemical agents, usually not for sulphur vulcanization, in particular synthetic rubbers known as EPM (ethylene and propylene copolymers), VKF
(fluorocarbon rubbers) and PU (polyurethane rubbers).
Even the use of the previously mentioned composite structure, consisting of a layer of cloth or fabric interposed in the rubber sheet and then embedded or inset therein, does not completely solve the problem In fact, even if the rubber sheet is in t6is way able to contain the mixhure during tbe forming step without undergoing excessive deformation, the final product has surFace corrugations, as a resuh of the shrinkage of the material during the cooling phase and the -albeit minimal -residual elasticity of the rubber.
It has now been discovered that all these problems can be completely and satisfactorily solved with a rubber sh8et structure of the type comprising two layers of rubber between which a layer of non-deformable cloth or fabric is interposed, said structure being characterized m that the base of the composite sheet is completed with a second layer of cloth or fabric consisting of non-deformable material, which thereby constitutes the outwardly directed siirface. The second layer of cloth or fabric also constitutes an outwardly directed surface which is suitable for being in contact with the oven surface.
In one aspect, the invention provides a composite structure for use as a supporting sheet in a process for production of slabs where a mixture composed of granulate material of selected particle size and synthetic resin and deposited in metered quantities on a supporting sheet is subjected to a vacuum compaction step with simultaneous application of a vibratory motion and to a subsequent hardening step, wherein the composite structure consists of a first layer of vulcanized rubber forming a first outwardly directed surface, a second layer of vulcanized rubber, a first layer of cloth or fabric of non-deformable material interposed between the first and second layer of vulcanized rubber, and a second layer of cloth or fabric of non-deformable material provided on the second layer of vulcanized rubber and forming another outwardly directed surface which is the base of the composite structure, and the composite structure is subjected to a step of dimensional stabilization which consists of heating to a temperature in the region of 160 C.
In one aspect, the invention provides a shaped sheet for the production of slabs from a material mixture of granulated stone material and/or sand and by a binding resin, the shaped sheet comprising a flat base and a peripheral frame projecting from the base for a predetermined height so as to define a seat of dimensions corresponding in plan to those of the slab to be produced, wherein the structure of the flat base comprises a first rubber layer of previously cured rubber forming a first surface adapted to be in contact with the material mixture and a second rubber layer of previously cured rubber, the first and second rubber layers having the same structure as regards the homogeneity of heat transfer, a first cloth made of one of a non-deformable cloth and a fabric interposed 4a between the first and second rubber layers, and a second cloth made of one of a non-deformable cloth and a fabric provided on the second rubber layer, wherein the second cloth comprises a second outwardly directed surface of the shaped sheet.
The specific aspects and advantages of the composite structure in accordance with the present invention wili appear more clearly from the foIIowing description, with reference to the drawings in which:
Figure 1 coincides with Fig. 3 of Italian application No. TV97A000148, illustrating therefore the structure of the rubber sheets which was used in the previously mentioned method;
Figure 2 is a view, similar to that of Figure 1, of the composite structure in accordance with the present invention; and Figure 3 is an enlarged cross-sectional view of the composite structure of the present invention corresponding to position A in Fig. 2.
It can be seen that Figure I corresponds to Figure 3 of Italian patent application No.
TV97A000148, now U.S. Patent 6,773,641.
It can be seen from this figure that the starting m'vcture 130 is deposited in a cavity defined by a lower sheet 120 and by an upper or covering sheet 132.
A perimetral border 120A, the inner surface of which has a predetermined inclination, is attached to the lower sheet 120.
In Figure 1, the sheet 120 has a composite structure consisting of a lower sheet of rubber 120 having a flat basis 120B and an inclined peripheral border 120A; a layer 120M
of substantially inextensible cloth or fabric (such as Kevlar, polyester or nylon) is embedded and an upper sheet of nibber 132 which is spaced from the said border 120A through a gap 100 of a predetermined thickness along its peripheral edge 132A. The end portion 120E of the slab, which is enclosed between the inclined muface 120C and a vertical cross-section defined by the fine 120D, is the scrap material to be removed at a subsequent step of the manufacturing process. References X
-ind S designate the thickness of the said peripheral border 120A resp. of the mixture 130.
'With reference now to the composite structure of the present invention, shown in Figures 2 and 5 :3, using where possible the same references as in Figure 1 and maicing particular reference to Figure 3, the sheet 120 comprises two layers of rubber 220A and 220B, between which the llayer of inextensible doth or fabric 220M is interposed.
As previously mentioned, the rubber of the layers 220A and B is an EPM rubber which is vulcanised by meatis of a peroxide usirig a known method.
'The selected rubber preferably has the following characterisdcs:
:Density 1.05 g/cm3 :Hardness fi4 Shore (A) Abrasion regstance 86 mm3 :Heat resistance 170 C
'The rubber is worked in such a way to aclueve a maximum controlled planarity of 0.5 mm per :linear metre, reaching the overall thickness of 4 mm.
In turn, the cloth or fabric of the layer 220M preferably is of the type comprising a weft of polyamide or nylon and a warp of polyester, and is pretensioned in both directions (both weft and waip).
As can be seen from Figure 3, a second layer of cloth or fabric 220N having the same characteristics as the layer 220M is added underneath the rubber layer 220B.
The composite sheet, thus formed, is preferably subjected to a stabilising treatment prior to use, consisting of heating for a few hours (generally from 1 to 3 hours) to a temperature higher than the m.aximwm operating temperature, so that, in the present method (in which resin hardening takes place at a temperature in the region of 150 C), the stabilising temperature is in the region of 160 C (for approximately 2 hours).
The desired results can be obtained with the sheet structure in accordance with the present invention.
In particular, it is desirable that both the lower sheet 220 and the upper sheet should have the same struct re, so as to guarantee pf:rfect hobiogeneity of thermal exchange with the mixture contained in the "sheath" defined by the two - upper and lower - rubber sheets.
Moreover, the lower cloth 220N also favours the handling of said sheath containing the mixture through the vorious stations of the slab production plant.
In particular, it is worth noting that with the stiucture according to the present invention the compressive strength or rather the resistance to extreme loads of the moulding sheath is increased, preventing the appearance of wrinides on the surfaces of the product.
a first layer of rubber (VRF, EPM, PU) TM
a first cloth or fabric of non-deformable material (Kevlar, polyester, nylon, aranvde) a second layer of rubber (EPM, NBR (Nitrile Butadiene Rubber)) a second cloth or fabric of non-deformable material.
Preferably this cloth or fabric is subjected to preliminary treatments, such as a pretensioning treatment, to avoid subsequent hysteresis phenomena, a theimal stabilization, etc.
However, certain requirements remain in connection with the rubber sheets and must be satisfied in order to obtain optimum results.
In sbort, these requirements correspond to the following characteristics which the rubber sheet nnist have:
a resistance to beat and chemical agents so as to withstand operating temperatures which during the resi*i hardening step are in the region of 150 C;
a good resistance to abrasion and tearing;
(c) retain substantially unaltered properties over time;
(d) possess optimal mechanical properties so as to contain the mixture without undergoing excessive deformations;
(e) undergo minimal shrinkage after forming so as to prevent the formation of surface irregularities in the final product; and (f) a good heat conductivity in order to favour the hardening of the slab.
- As regards the nature of the rubber, the most suitable are of a polymeric type resistant to temperature and to chemical agents, usually not for sulphur vulcanization, in particular synthetic rubbers known as EPM (ethylene and propylene copolymers), VKF
(fluorocarbon rubbers) and PU (polyurethane rubbers).
Even the use of the previously mentioned composite structure, consisting of a layer of cloth or fabric interposed in the rubber sheet and then embedded or inset therein, does not completely solve the problem In fact, even if the rubber sheet is in t6is way able to contain the mixhure during tbe forming step without undergoing excessive deformation, the final product has surFace corrugations, as a resuh of the shrinkage of the material during the cooling phase and the -albeit minimal -residual elasticity of the rubber.
It has now been discovered that all these problems can be completely and satisfactorily solved with a rubber sh8et structure of the type comprising two layers of rubber between which a layer of non-deformable cloth or fabric is interposed, said structure being characterized m that the base of the composite sheet is completed with a second layer of cloth or fabric consisting of non-deformable material, which thereby constitutes the outwardly directed siirface. The second layer of cloth or fabric also constitutes an outwardly directed surface which is suitable for being in contact with the oven surface.
In one aspect, the invention provides a composite structure for use as a supporting sheet in a process for production of slabs where a mixture composed of granulate material of selected particle size and synthetic resin and deposited in metered quantities on a supporting sheet is subjected to a vacuum compaction step with simultaneous application of a vibratory motion and to a subsequent hardening step, wherein the composite structure consists of a first layer of vulcanized rubber forming a first outwardly directed surface, a second layer of vulcanized rubber, a first layer of cloth or fabric of non-deformable material interposed between the first and second layer of vulcanized rubber, and a second layer of cloth or fabric of non-deformable material provided on the second layer of vulcanized rubber and forming another outwardly directed surface which is the base of the composite structure, and the composite structure is subjected to a step of dimensional stabilization which consists of heating to a temperature in the region of 160 C.
In one aspect, the invention provides a shaped sheet for the production of slabs from a material mixture of granulated stone material and/or sand and by a binding resin, the shaped sheet comprising a flat base and a peripheral frame projecting from the base for a predetermined height so as to define a seat of dimensions corresponding in plan to those of the slab to be produced, wherein the structure of the flat base comprises a first rubber layer of previously cured rubber forming a first surface adapted to be in contact with the material mixture and a second rubber layer of previously cured rubber, the first and second rubber layers having the same structure as regards the homogeneity of heat transfer, a first cloth made of one of a non-deformable cloth and a fabric interposed 4a between the first and second rubber layers, and a second cloth made of one of a non-deformable cloth and a fabric provided on the second rubber layer, wherein the second cloth comprises a second outwardly directed surface of the shaped sheet.
The specific aspects and advantages of the composite structure in accordance with the present invention wili appear more clearly from the foIIowing description, with reference to the drawings in which:
Figure 1 coincides with Fig. 3 of Italian application No. TV97A000148, illustrating therefore the structure of the rubber sheets which was used in the previously mentioned method;
Figure 2 is a view, similar to that of Figure 1, of the composite structure in accordance with the present invention; and Figure 3 is an enlarged cross-sectional view of the composite structure of the present invention corresponding to position A in Fig. 2.
It can be seen that Figure I corresponds to Figure 3 of Italian patent application No.
TV97A000148, now U.S. Patent 6,773,641.
It can be seen from this figure that the starting m'vcture 130 is deposited in a cavity defined by a lower sheet 120 and by an upper or covering sheet 132.
A perimetral border 120A, the inner surface of which has a predetermined inclination, is attached to the lower sheet 120.
In Figure 1, the sheet 120 has a composite structure consisting of a lower sheet of rubber 120 having a flat basis 120B and an inclined peripheral border 120A; a layer 120M
of substantially inextensible cloth or fabric (such as Kevlar, polyester or nylon) is embedded and an upper sheet of nibber 132 which is spaced from the said border 120A through a gap 100 of a predetermined thickness along its peripheral edge 132A. The end portion 120E of the slab, which is enclosed between the inclined muface 120C and a vertical cross-section defined by the fine 120D, is the scrap material to be removed at a subsequent step of the manufacturing process. References X
-ind S designate the thickness of the said peripheral border 120A resp. of the mixture 130.
'With reference now to the composite structure of the present invention, shown in Figures 2 and 5 :3, using where possible the same references as in Figure 1 and maicing particular reference to Figure 3, the sheet 120 comprises two layers of rubber 220A and 220B, between which the llayer of inextensible doth or fabric 220M is interposed.
As previously mentioned, the rubber of the layers 220A and B is an EPM rubber which is vulcanised by meatis of a peroxide usirig a known method.
'The selected rubber preferably has the following characterisdcs:
:Density 1.05 g/cm3 :Hardness fi4 Shore (A) Abrasion regstance 86 mm3 :Heat resistance 170 C
'The rubber is worked in such a way to aclueve a maximum controlled planarity of 0.5 mm per :linear metre, reaching the overall thickness of 4 mm.
In turn, the cloth or fabric of the layer 220M preferably is of the type comprising a weft of polyamide or nylon and a warp of polyester, and is pretensioned in both directions (both weft and waip).
As can be seen from Figure 3, a second layer of cloth or fabric 220N having the same characteristics as the layer 220M is added underneath the rubber layer 220B.
The composite sheet, thus formed, is preferably subjected to a stabilising treatment prior to use, consisting of heating for a few hours (generally from 1 to 3 hours) to a temperature higher than the m.aximwm operating temperature, so that, in the present method (in which resin hardening takes place at a temperature in the region of 150 C), the stabilising temperature is in the region of 160 C (for approximately 2 hours).
The desired results can be obtained with the sheet structure in accordance with the present invention.
In particular, it is desirable that both the lower sheet 220 and the upper sheet should have the same struct re, so as to guarantee pf:rfect hobiogeneity of thermal exchange with the mixture contained in the "sheath" defined by the two - upper and lower - rubber sheets.
Moreover, the lower cloth 220N also favours the handling of said sheath containing the mixture through the vorious stations of the slab production plant.
In particular, it is worth noting that with the stiucture according to the present invention the compressive strength or rather the resistance to extreme loads of the moulding sheath is increased, preventing the appearance of wrinides on the surfaces of the product.
Claims (11)
1. A composite structure for use as a supporting sheet in a process for production of slabs where a mixture composed of granulate material of selected particle size and synthetic resin and deposited in metered quantities on a supporting sheet is subjected to a vacuum compaction step with simultaneous application of a vibratory motion and to a subsequent hardening step, wherein:
the said composite structure consists of:
a first layer of vulcanized rubber forming a first outwardly directed surface;
a second layer of vulcanized rubber;
a first layer of cloth or fabric of non-deformable material interposed between said first and second layer of vulcanized rubber; and a second layer of cloth or fabric of non-deformable material provided on said second layer of vulcanized rubber and forming another outwardly directed surface which is the base of the composite structure; and the said composite structure is subjected to a step of dimensional stabilization which consists of heating to a temperature in the region of 160°C.
the said composite structure consists of:
a first layer of vulcanized rubber forming a first outwardly directed surface;
a second layer of vulcanized rubber;
a first layer of cloth or fabric of non-deformable material interposed between said first and second layer of vulcanized rubber; and a second layer of cloth or fabric of non-deformable material provided on said second layer of vulcanized rubber and forming another outwardly directed surface which is the base of the composite structure; and the said composite structure is subjected to a step of dimensional stabilization which consists of heating to a temperature in the region of 160°C.
2. A composite structure according to claim 1, wherein rubber of the said first and second layer is a rubber of the EPM type and is vulcanized by means of a peroxide.
3. A composite structure according to claim 1 or 2, wherein said cloths are formed by a polyester warp and nylon weft.
4. A composite structure according to any one of claims 1 to 3, wherein said step of dimensional stabilization in the region of 160°C has a duration of 1-3 hours.
5. A composite structure according to any one of claims 1 to 4, wherein it is also used as a protective sheet which covers said mixture composed of granulate material of selected particle size and synthetic resin.
6. A shaped sheet for the production of slabs from a material mixture of granulated stone material and/or sand and by a binding resin, the shaped sheet comprising: a flat base and a peripheral frame projecting from the base for a predetermined height so as to define a seat of dimensions corresponding in plan to those of the slab to be produced;
wherein the structure of the flat base comprises a first rubber layer of previously cured rubber forming a first surface adapted to be in contact with the material mixture and a second rubber layer of previously cured rubber, the first and second rubber layers having the same structure as regards the homogeneity of heat transfer, a first cloth made of one of a non-deformable cloth and a fabric interposed between the first and second rubber layers, and a second cloth made of one of a non-deformable cloth and a fabric provided on the second rubber layer, wherein the second cloth comprises a second outwardly directed surface of the shaped sheet.
wherein the structure of the flat base comprises a first rubber layer of previously cured rubber forming a first surface adapted to be in contact with the material mixture and a second rubber layer of previously cured rubber, the first and second rubber layers having the same structure as regards the homogeneity of heat transfer, a first cloth made of one of a non-deformable cloth and a fabric interposed between the first and second rubber layers, and a second cloth made of one of a non-deformable cloth and a fabric provided on the second rubber layer, wherein the second cloth comprises a second outwardly directed surface of the shaped sheet.
7. A shaped sheet according to claim 6, wherein the rubber is ethylene and propylene copolymers or fluorocarbon rubbers or polyurethane rubbers.
8. A shaped sheet according to claim 6 or 7, wherein the first and second cloths are formed by a polyester warp and a nylon weft.
9. A shaped sheet according to any one of claims 6 to 8, wherein stabilization treatment heating is performed for 1-3 hours on the flat base.
10. A shaped sheet according to any one of claims 6 to 9, wherein the shaped sheet comprises a flat base and an inclined peripheral border so as to constitute a cavity into which the material mixture is deposited to undergo the process for the production of a slab.
11. A shaped sheet according to any one of claims 6 to 10, wherein the first and second rubber layers are cured by means of a peroxide using a vulcanization method.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT1999TV000055U IT248137Y1 (en) | 1999-12-06 | 1999-12-06 | STRUCTURE OF RUBBER SHEET USEFUL IN THE MANUFACTURE OF GRANULATED SLABS OR SANDS OF STONE MATERIAL TIED WITH HARDENABLE RESIN |
| ITTV99U000055 | 1999-12-06 | ||
| PCT/EP2000/011883 WO2001042007A1 (en) | 1999-12-06 | 2000-11-28 | Fabric reinforced rubber for sheet for the production of slabs of resin hardend finely divided stone material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2357009A1 CA2357009A1 (en) | 2001-06-14 |
| CA2357009C true CA2357009C (en) | 2007-05-15 |
Family
ID=11420631
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002357009A Expired - Lifetime CA2357009C (en) | 1999-12-06 | 2000-11-28 | Rubber sheet structure for use in the production of slabs of granulate or fine particles of stone material bonded with hardening resin |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA2357009C (en) |
| ES (1) | ES2245139B2 (en) |
| IL (1) | IL143827A (en) |
| IT (1) | IT248137Y1 (en) |
| WO (1) | WO2001042007A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006013589A1 (en) * | 2004-08-05 | 2006-02-09 | Dario Toncelli | Tray-shaped mould made of a vulcanized composite material |
| ITTV20100141A1 (en) * | 2010-10-25 | 2012-04-26 | Luca Toncelli | MOLD FOR THE MANUFACTURE OF AGGLOMERATED MATERIAL SHEETS |
| IT202000016273A1 (en) * | 2020-07-06 | 2022-01-06 | Siti B & T Group Spa | EQUIPMENT FOR THE CREATION OF SLABS IN CERAMIC MATERIAL |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4744843A (en) * | 1983-11-03 | 1988-05-17 | The Goodyear Tire & Rubber Company | Release treatment using a non-reinforcing, non-woven fabric for conveyor belt curing |
| US5498470A (en) * | 1992-07-23 | 1996-03-12 | Day International, Inc. | Printing blanket having improved dynamic thickness stability and method of making |
| IT1297285B1 (en) * | 1997-10-27 | 1999-09-01 | Luca Toncelli | PROCEDURE FOR THE PRODUCTION OF SLABS OF GRANULES AND/OR SANDS OF STONE MATERIAL BONDED WITH A HARDINABLE RESIN AND SHAPED SHEET |
-
1999
- 1999-12-06 IT IT1999TV000055U patent/IT248137Y1/en active
-
2000
- 2000-11-28 CA CA002357009A patent/CA2357009C/en not_active Expired - Lifetime
- 2000-11-28 ES ES200150055A patent/ES2245139B2/en not_active Expired - Fee Related
- 2000-11-28 IL IL14382700A patent/IL143827A/en active IP Right Grant
- 2000-11-28 WO PCT/EP2000/011883 patent/WO2001042007A1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| IL143827A0 (en) | 2002-04-21 |
| ITTV990055V0 (en) | 1999-12-06 |
| IT248137Y1 (en) | 2002-12-10 |
| ES2245139B2 (en) | 2007-03-16 |
| ES2245139A1 (en) | 2005-12-16 |
| WO2001042007A1 (en) | 2001-06-14 |
| CA2357009A1 (en) | 2001-06-14 |
| ITTV990055U1 (en) | 2001-06-06 |
| IL143827A (en) | 2005-06-19 |
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| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20201130 |