Classifications

• • 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
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
• • 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
  • B28B7/346—Manufacture of moulds
• • 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
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/38—Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
  • B29C33/3842—Manufacturing moulds, e.g. shaping the mould surface by machining
• • 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
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/38—Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
  • B29C33/40—Plastics, e.g. foam or rubber
  • B29C33/405—Elastomers, e.g. rubber
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2027/00—Use of polyvinylhalogenides or derivatives thereof as moulding material
  • B29K2027/12—Use of polyvinylhalogenides or derivatives thereof as moulding material containing fluorine
  • B29K2027/18—PTFE, i.e. polytetrafluorethene, e.g. ePTFE, i.e. expanded polytetrafluorethene

Definitions

• the present invention relates to a mould used for the production of slabs of agglomerated stone material and to a method for the manufacture thereof.
• the tray-shaped moulds used hitherto in the abovementioned techniques have been produced in the form of a sandwich consisting of one or more cloths arranged inside and several rubber layers for coating the outer surface of the moulds, both that of the base of the moulds and that of the cover (see EP-A- 1,027,205 and WO-A-01 42007).
• the resins used as a binder for the mix emit, in particular during hot-hardening of the abovementioned slabs (involving temperatures in the region of 120-130 0 C), vapours which have an aggressive action on the rubber.
• the polyester resins emit styrene vapours prone to cause the rapid deterioration of the rubber surface of the moulds.
• the protective sheet consists of a disposable film arranged between the rubber-coated surface and the mix.
• the material from which the film is made is normally based on PVA (polyvinyl alcohol), which is impermeable to the styrene vapours, resistant to the temperatures reached during hardening of the slabs and facilitates separation of the slabs from the moulds after hardening.
• PVA polyvinyl alcohol
• the film is both ready available in rolls, so that it may be directly applied onto the outer surface of the moulds, or may be formed in situ by means of spraying and subsequent drying.
• a method according to the invention for manufacturing a mould comprises the steps of:
• the rubber is EPM (i.e. a terpolymer obtained from ethylene and propylene monomers) or EPDM (Le. a terpolymer obtained from ethylene and propylene monomers and at least one third monomer consisting of a non-conjugated diene), and said film consists of a layer of PTFE (polytetrafluoroethylene) having a superficial substrate compatible with the rubber on which it is deposited.
• PTFE polytetrafluoroethylene
• the vulcanization operation is performed at high pressure (about 50 bar) and at a temperature of about 165°C.
• - Fig. 1 shows in schematic form a tray-shaped mould used for the production of slabs and filled with a mix of agglomerated stone material in which the binding agent consists of resins, in particular polyester resins;
• - Fig. 2 shows a cross-sectional view of the base of the mould according to Fig. 1, which is able to come into contact with said mix for formation of the slab.
• a base 100 and a cover 200 of a tray-shaped mould 10 have a square or rectangular shape.
• the base 100 consists essentially of a flat surface 12 and four side walls 14 (only two are shown in Fig. 1), while the cover 200 consists solely of a flat surface.
• the structure shown in Fig. 2 relates to the flat surface 12 of the base 100, but also the side walls 14 of the base 100 and/or the cover 200 may have the same structure.
• said structure comprises (as well as, in a manner already known, two layers of synthetic rubber, i.e. a lower layer 123 and an upper layer 125, and two reinforcing layers, i.e. a middle layer 124 and an outer layer 122, so as to form a sandwich) a film 130 which is combined with the upper layer of rubber 125 and partly made with one or more fluorinated polymers and partly with material compatible with the rubber of said layer 125.
• the mix of agglomerated stone material is then spread over said film 130 during manufacture of the slabs until the end of the hardening step and is incorporated in the said structure.
• said film 130 consists of a layer 131 of
• PTFE polytetrafluoroethylene lined underneath with a superficial substrate or coating 132 of material compatible with the synthetic rubber from which at least the already mentioned upper layer 125 is made.
• the superficial substrate or coating 132 acts as a layer promoting adhesion during the following vulcanization step by means of which said structure is made permanent.
• the rubber of said layer 125 is preferably EPM (i.e. a terpolymer obtained from ethylene and propylene monomers) or EPDM (Le. a terpolymer obtained from ethylene and propylene monomers and at least one third monomer consisting of a non-conjugated diene) since they are elastomers particularly resistant to high temperatures.
• EPM i.e. a terpolymer obtained from ethylene and propylene monomers
• EPDM Le. a terpolymer obtained from ethylene and propylene monomers and at least one third monomer consisting of a non-conjugated diene
• the entire film 130 may also be made using a mixture of one or more fluorinated polymers and synthetic rubber and, in this case also, incorporated in said structure.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Laminated Bodies (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=36101831

Family Applications (1)

Country Status (2)

Cited By (6)

Citations (4)

• 2004
  • 2004-12-15 IT ITTV20040151 patent/ITTV20040151A1/it unknown
• 2005
  • 2005-12-01 WO PCT/EP2005/056383 patent/WO2006063940A1/en active Application Filing

Patent Citations (4)

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