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
  • B29C63/00—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor
  • B29C63/02—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor using sheet or web-like material

Definitions

• the present invention relates to a process for producing bathroom or kitchen sanitary ware comprising processing steps that are advantageously simple and effective in obtaining a product in a versatile, flexible and standardised manner.
• the invention relates to a process which considerably reduces the number of operating steps as well as a strong decrease in the use of solvents and ensuing decrease in emissions.
• the final product is technically different while maintaining, if not improving, the performance.
• these processes generally use metal or composite moulds based on glass or carbon fibres bonded together by means of epoxy or polyester resins.
• the moulds are generally filled with a mixture of thermosetting or thermoplastic resin, such as for example acrylic, polyester, epoxy resins and combinations thereof, optionally in association with mineral fillers, polymeric fillers, catalysts, stabilising additives and/or coloured pastes (called mixture hereinafter).
• the first step is to deposit a layer of gelcoat comprised between 0.5 and 2 mm on the surface of the mould.
• the gelcoat is sprayed by means of manual or automated processes.
• Gelcoat is a known liquid product based on polyester, vinyl ester and/or epoxy resin which confers aesthetic characteristics and stain resistance to the final product.
• After said spraying there follows a step for drying the gelcoat in an oven at a temperature comprised between 25° and 65°C and a period of time comprised between 30 and 90 minutes.
• the mould may be closed just before or immediately after the drying step.
• the mixture is injected into the mould after the drying step.
• the mixture can be injected by gravity or pressure.
• the article is the de-moulded after filling the mould with the resin mixture, and after the time necessary for the hardening of the mixture has elapsed. Subsequently, optionally, an oven hardening is possibly carried out at a temperature and for a period of time which allow a complete catalysis/polymerisation. The time may vary between 1 and 4 hours and the temperature varies between 50° and 120°C.
• the final article consists of a structural body consisting of the polymerised mixture and a surface coating (gelcoat) in contact with the user and adhering to the structural body by means of a sort of mechanical/chemical interpenetration/bond between the two materials forming said body and said coating.
• a surface coating gelcoat
• US2006147655 describes a non-porous solid surface structure comprising a thermoplastic, flat, unitary and non-porous polymeric matrix made of polymethylmethacrylate, polyvinylchloride, polycarbonate or combinations thereof, and a visible decorative object permanently fixed to the matrix, wherein the decorative object extends at least on one edge of the matrix.
• the thermoplastic matrix in the form of two sandwich layers on the decorative object, is unitary, i.e., a single non- laminated piece.
• the production process specifies that said two layers are subjected to two separate heating and forming pressure processes, at a softening temperature lower than a possible coating film applied by interposing glue.
• a product thus obtained is structurally complex on the one hand and on the other hand equally complex to manufacture due to the number of steps to be carried out which can easily increase the risk of errors which result in defects of the final product.
• the technical problem underlying the present invention lies in providing a method for producing bathroom or kitchen sanitary articles alternative to the process described above so as to avoid the aforementioned drawbacks.
• a first object of the present invention is a process for producing bathroom or kitchen sanitary ware without the gelcoat deposition step and unnecessary heating steps.
• a second object is a process provided with standardisation of the production steps with ensuing reduction of the waste, flexibility of manufacture of the articles and reduction of manpower.
• a further object is an article that can be obtained according to the process of the invention.
• An even further object is a plant for the production of the article.
• FIG. 1 represents a schematic view of a plant for the production of an article according to the invention
• FIG. 2 represents a schematic view of a first processing step of the process of the invention
• FIG. 3 represents a schematic view of a second processing step of the process of the invention.
• FIG. 4 represents a schematic view of a third processing step of the process of the invention.
• the step of eliminating the gelcoat deposit must in any case be replaced by a finishing step necessary to coat the mixture of thermosetting/thermoplastic resins which - as such - should not come into contact with the skin of a person and it is devoid of stain resistance characteristics and it does not impart the sought-after aesthetic effects.
• the solution that was found consists in replacing the gelcoat with a layer, film or sheet of plastic material produced in a preliminary step and subsequently glued onto the structural body of the article.
• the production process according to the present invention comprises the steps of:
• the first step of providing the structural body comprises the moulding of a mixture of thermoplastic or thermosetting resins according to technologies known in the plastic moulding industry.
• moulding consists in providing a mould usually made of metal material such as steel or alloys thereof, alternatively made of composite material based on glass or carbon fibres bonded together by means of epoxy or polyester resins or mixtures thereof.
• a layer of release material such as for example starches, stearates, silicone resins, mineral powders.
• the mould is closed and a mixture of thermosetting or thermoplastic resins is injected thereinto, possibly in association with mineral and/or polymeric fillers, catalysts, additives and/or coloured pastes.
• the most commonly used resins part of said mixture are preferably selected from acrylic resins, polyester resins, epoxy or polyurethane resins.
• Mineral fillers could include calcium carbonate, aluminium trihydrate (ATH), quartz, phyllite; additives may for example include glass fibre, graphite, talc, natural fibres, accelerators; the most common catalysts include organic peroxides; the coloured pastes consist of a mixture of thermosetting and/or thermoplastic resins and natural pigments such as for example titanium dioxide for white.
• the aforementioned mixture is usually injected by gravity, or at a pressure comprised between 0.5 bars and 4 bars, at a temperature comprised between 20°C and 50°C and left there for a period of time comprised between 20 min and 120 min.
• the article obtained is de-moulded, i.e., removed from the mould and possibly subjected to an oven hardening step for the completion of catalysis/polymerisation for a period of time comprised between 1 and 4 hours at a temperature between 50°C and 120°C.
• This hardening step is carried out or not carried out depending on the formulation used for the mixture. As a matter of fact, it is known that if the appropriate hardening catalysts and/or additives are not used, the aforementioned heating step is carried out to ensure a 100% complete catalysis.
• a structural body of the article ready to be subjected to the subsequent step of applying a plastic film is obtained at the end of the aforementioned steps.
• At least one through hole on the structural body for example forming the hole for housing a drain of a shower tray, sink or bath tub of bathroom or kitchen sanitary ware is preferably provided before said application, through a mechanical process.
• the surface of the body that will receive the plastic film is treated so as to receive the film adequately.
• the treatment consists in sanding the surface that will receive the film with sandpaper with grit comprised between 80 and 600. Sanding may be carried out manually or using an orbital disc sander. Alternatively, the surface may be sandblasted with quartz or calcium bicarbonate or polymer grit or it can be cleaned with descaling agents and/or chemical cleaners/solvents. The purpose of this step is to remove any residues of release agent deriving from the moulding process and more generally to make the surface suitable for gluing.
• the subsequent step of applying the layer of glue on a first surface of the plastic film, opposite to the possible surface with particular aesthetic treatments, comprises the use of a one or two-component glue preferably selected from epoxy, acrylic and polyurethane glues.
• a one or two-component glue preferably selected from epoxy, acrylic and polyurethane glues.
• glues are applied by spraying or specific application machine, and are dried for at least 30 minutes at ambient temperature.
• the plastic film is selected from those already available on the market and generally used for the coating of furniture or parts thereof, such as for example films based on PVC, PE, PET or other materials.
• the type of material that constitutes the film depends on the desired performance, such as resistance to stain, chemical agents, aesthetic and touch characteristics, and many others.
• This plastic film also known as polymeric sheet
• the surface may be glossy or opaque.
• the thickness ranges from 0.2 to 1 mm.
• the step of laying the glue sheet is carried out onto a first surface of the film layer, opposite to the surface having eventually particular aesthetic treatments, and, such as the step of directly applying onto the cavity of the shaped body, comprised the use of a mono or bi-component glue preferably selected form epoxydic, acrylic, polyurethan glues.
• a mono or bi-component glue preferably selected form epoxydic, acrylic, polyurethan glues.
• said glues are sprayed or laid with a specific applying machine.
• the film is subjected to the heating step, whose temperature is around the HDT value of the polymer forming the film, a value calculated according to the ISO 75 and ASTM D648 protocols.
• a value calculated according to the ISO 75 and ASTM D648 protocols is comprised between 80°C and 150°C, more preferably between 70°C and 100°C for a period of time comprised between 10 seconds and 2 minutes.
• heating is carried out in a differentiated manner.
• the heating must be greater to allow a greater softness/plasticity which allow the film to lie more precisely at changes in surface or, in other words, on non-planar surfaces of the structural body or farther away from the heat source.
• the variation of the thermal energy power at the aforementioned most critical points will depend on the thickness and on the type of material used for the film. In any case, these types of adjustments are known to the man skilled in the art.
• the film thus prepared is positioned so as to close the cavity of the shaped structural body to be coated eventually with its side covered with glue directed toward said cavity.
• a pressure is applied on the plastic film preferably comprised between 1 and 6 bars, more preferably between 2 and 4 bars, by fluxing compressed air and vacuum preferably between -0.2 and -0.8 bars on the side of the structural body opposite to the one for receiving the plastic film by means of a vacuum pump.
• This step is carried out in a sealed chamber, as explained hereinafter, which allows to create an overpressure space where the film is pressed against the surface of the cavity of the structural body and an under-pressure space where the film is sucked against said surface.
• said actions which are activated in combination on two opposite sides of the film, allow to obtain a perfect adhesion between the two components of the article in a very simple but considerably effective manner, avoiding the many steps due to the application of gelcoat as well as its environmental impact or multiple heating operations.
• the vacuum application step is carried out first and the pressure application step is carried out for 20-70 seconds after a period of time comprised between 10 and 60 seconds.
• This specific combination has proved to be surprisingly effective in that the adhesion of the polymeric film with the layer of glue on the structural body is optimal and i.e.
• both the aforementioned heating step with differentiated areas and the combination of pressure and vacuum allow to obtain an optimum degree of softening in the entire film so as to perfectly adapt to the whole shaped surface of the structural body without causing stretching, with formation of bubbles, or excessive softening, with formation of creases.
• the product obtained is therefore a moulded article comprising a structural body in a mixture of thermosetting or thermoplastic resin covered - on a first functional surface - by a plastic film applied by interposing a layer of glue.
• a product thus obtained differs from the aforementioned products in that the structural body of the prior art is covered by a layer of gelcoat which is directly applied on a surface of said body without interposing glue but through physical/mechanical interpenetration into the material that forms the body.
• the process for producing articles for bathroom or kitchen sanitary ware is preferably carried out with a plant 1 , schematically shown in figure 1 , comprising:
• a station 2 for moulding a shaped-structural body made of a mixture of thermosetting or thermoplastic resin, and eventually for applying a layer of glue onto the cavity of said shaped body;
• a station 3 comprising elements 22 for heating said film with glue eventually comprising means for applying a layer of glue onto a first surface of said film;
• the moulding station 2 consists of an entirely conventional plastic material injection mould which will therefore not be described and illustrated in detail hereinafter. The operating parameters of the mould will be as described above with reference to the process.
• the structural body before passing to the covering station, the structural body may be treated in a finishing station (not shown) in which the functional surface of the structural body is cleaned to eliminate traces of release agent.
• This station comprises per se known automatic or manual devices of the mechanical type such as sanding machines or sandblasting machines, or cleaners of the chemical type.
• the cavity of the body can be covered of glue by means of conventional or robotic spraying guns or rollers.
• the heating, and eventually applying glue station 3 consists of a support or frame 20 provided with grippers or clamps 21 adapted to keep the film 10 tensioned until it is substantially flat but without causing stretching.
• a heating element 22 is positioned close to the film surface, or the same film can be moved in a heating station or oven (not shown), where said frame is positioned close to a coil, infrared lamps or a heated-air blower to heat the film, eventually with the glue, at a temperature and for a time as disclosed above and preferably at the differential condition disclosed above.
• the station 3 can comprises an entirely conventional spray gun or roller system (not shown) which deposits a layer of glue as described in the previous process on either side of the film.
• the frame 20 with the heated film 10 is then brought to the station 4 for covering the structural body 11 .
• This station comprises a sealed chamber 30 inside which the shaped structural body 11 suspended on a support 13 is first positioned and then the frame 20 with the film provided with glue is subsequently positioned so as to close the cavity 12 of the shape of the structural body.
• the chamber 30 is closed and a pressure is applied to the film by means of a blower (not shown) which presses the film against the surface of said cavity 12 and a vacuum pump (not shown) suctions air from the side of the structural body opposite to the one for receiving the film through one or more holes obtained in the thickness of the structural body.
• the operating parameters of the blower and the vacuum pump are those indicated in the process.
• the vacuum pump is activated followed by the blower which presses the film as specified above.
• the plant 1 can then comprise a last station (not shown) for removing the excess material both of the structural body 11 and of the film 10 by means of entirely conventional numerical control machines or manual methods.
• the application of the plastic film advantageously allows to standardise the production with strong increases in productivity and great speed and ease in making the product versatile thanks to the immediate availability of films with functional and aesthetic characteristics ready for application.
• the application of a preformed plastic film on a structural body by gluing also has the advantage of combining the resistant mechanical characteristics of the structural body with the resistant chemical, aesthetic and hygienic characteristics of the plastic film in order to overcome the requirements of the regulations in force.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Cited By (1)

Citations (2)

• 2019
  • 2019-12-09 IT IT102019000023337A patent/IT201900023337A1/it unknown
• 2020
  • 2020-11-30 WO PCT/IB2020/061273 patent/WO2021116818A1/en active Application Filing

Patent Citations (2)

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