Sandwich Panel is produced in a continue line with 5 types of insulation materials including such as, Glasswool, Polyurethane (PUR), Polyisocyanurate (PIR) and Expanded Polystyrene in different insulation thicknesses. As external and internal surfaces of sandwich panel, painted galvanize, galvalum, galfan, alu-zinc, stainless steel, painted or natural aluminum materials can be used.
They are manufactured as polyester, plastisol, PVdf and food safe painted according to the needs of the Project. They can be manufactured in all RAL codes.
Sandwich panels are lightweight but durable construction materials which are formed by taking the best characteristics of their components.
The increase in demand for Cold Storage and energy crises occurred at the end of the 2nd World War led to taking the first step of the Sandwich Panel production. Sandwich panel has become a material demanded in constructions upon the fast and modern construction demand; the energy costs arising from the energy crisis worldwide following the 2nd World War and architects' realization of the sandwich panel's design elasticity and diversity.
Cold Storage Panel
Pre-painted metal is obtained by painting galvanized steel and aluminum in a continuous production line, with coil coating technique. In coil coating technique, galvanized or aluminum roll is opened in the continuous painting line and firstly, surface cleaning process is applied. The oil and unwanted substances are removed from the surface to be painted. Then, chromating process is applied to the sheet's surface and a surface suitable for painting is obtained. Firstly, epoxy primer is applied on both sides of the metal and it the primed metal is then sent to an oven for curing. The insulating layer or its adhesive is adhered to the metal by means of the epoxy primer layer applied to the insulated surface of the metal. And by this way the sandwich panel gets a composite structure. Since there is no epoxy primer layer in the insulated layer of the naked embossed aluminium, insulation layer cannot adhere to the metal very well and it can shear off in time.
The colors desired as a final coat are selected from the RAL catalogue. It is painted in RAL color and type, and cured again. Rolls wrapped as painted. With Coil Coating technique, a uniform paint thickness is obtained at every point of the steel surface. Due to the geographical and environmental characteristics of the projects's location, polyester, PVdF, plastisol, foodsafe or polyurethane paint is used on the epoxy primer. These paints with different technical characteristics common point is to be wet paints. Paint is the most important factor that ensures metal's long lasting. The metals painted with coil coating technique can be processed easily.
Painted surface is not affected during the forming process. Paint types have different warranty periods. These periods vary depending on the environmental, geographic and climatic conditions and use. The endurance of coil coating painted sheets is 6 years for the polyester paints under normal conditions and for PVdf and plastisol paints at locations without air pollution, acidic and heavy metals and away from the sea and for about 15-20 years. In case of continuous maintenance, the expected life can be 20 years and over.
Tone differences may occur when the colors in the RAL catalogue are applied onto the metal. Therefore, in project productions, production should be made by using the rolls painted in the same batch. A protective film is applied to the outer surfaces of the painted sheet metal. The film layer must be stripped off the paint surface before screwing during installation.
Polyester is the most simple and widely used topcoat paint among the paint types. It is widely used in interior and exterior surfaces. It is economical and it can be shaped easily. Since it has most appropriate cost, it can be supplied in all RAL codes.
PVdf is a topcoat paint which is the most resistant against UV rays, moisture and humid environments and heat. It is especially used in exterior metal surfaces in buildings close to coasts and seaside. Since it has excellent UV resistance, it is the most resistant paint against color fading.
Plastisol is the topcoat paint that is resistant to acidic and alkaline environments. Its resistance to corrosion and chemical oils is at the highest level. It is a flexible and thus shaped easily. It has high impact resistance. Plastisol can not be used in exterior surfaces in hot countries since its UV resistance is low. It shows superior performance in cold, humid climates. If desired patterns can be formed on the surface.
Foodgrade or foodsafe paints are food compatible topcoat paints used in cold stores of food sector. They are especially resistant to oils, acids, alkalies and chemicals. They are suitable for vapor resistant and cold storage areas. They are free of solvents and toxic substances. They are resistant to radiation, humidity and moisture; easy to clean and have a good corrosion resistance.
Polyurethane is a two-component and alkyd isocyanate-based topcoat paint with semi-matte finish. Since it is a soft paint, it is elastic and resistant to scratches and impacts. It has high UV resistance and it is resistant to sudden temperature changes. It has low solvent strength but high mechanical and chemical resistance. It is preferred in sectoral and industrial constructions since it has anti-corrosive effect.
Silicone modified polyester is a topcoat paint with high solvent resistance. It has high corrosion and temperature resistance. It is an impact resistant paint that it is easy to clean. Silicone is suitable for application in high-rise buildings due to its color brilliance and resistance against fading.
Performance Table of Paint Types
Comparative Properties and Performance Table was created to provide a description of various roll coating topcoat paint physical and performance characteristics. This chart is intended to provide general information only. Since Performance Table addresses only for the topcoat, the graphics can only describe the overall system performance.
Division of Colours in Terms of Degree of Heat Absorption
Sandwich panels consist of three layers such as external sheet, insulation core and internal sheet. Due to physical properties of these layers, Sandwich panels are open to the harmful effects caused by different indoor and outdoor temperatures in terms of thermal expansion and rigidity. Steel, forms the outer and ınner surface of panel, has a higher expansion and shrinkage values than insulation core under the temperature. And because the steel is joined with the back coat to the core insulation and has different expansion properties, layers can be seperated, ondulation can be seen as bubbles and bulges when the limit values exceed under high temperature.
Light coloured panels stresses do not reach limit values while the dark and very dark colours influence must be taken into account and added up to the calculation of permanent and variable loads (panel dead load, structural loading, wind and snow load, etc.) Another harmful effect results from the fact that sandwich panels always operate between two environments with different temperatures. Normally, indoor temperature is above zero (+20°C) while the outside temperature is sub-zero (-30°C). Quite opposite conditions may occur in the case of freezers where indoor temperature may reach even -40°C while outdoors +30°C. As a result, external and internal surfaces behave differently - cold surface shrinks while warm lining expands, which causes bending of the entire panel.
In order to assess the influence of thermal loads on the panels, all available colours have been divided into three brightness groups, based on the degree of heat absorption. According to the EN 14509:2013 standard, the temperature of external lining (T1) reaches maximum value in summer, and depends on the colour and the degree of reflection of the surface. The T1 values that are minimum values for load capacity calculations and sufficient for calculating limit conditions of use are as follows:
Very light colours, Light colours, Dark colours, Where RG is the reflection grade in relation to magnesium oxide (100%)
As you can see from the values dark coloured panels expose to thermal load compared to light coloured panels. Due to light coloured panels, dark coloured panels have higher risk of fading, abrasion, colour gradation and ondulation risk.
Polyurethane is rigid polyurethane foam formed by the mixture of two main components named as polyol and isocyanurate under special production conditions, with catalyst materials and under high pressure. It has a closed cell structure. Thereby, it can provide excellent thermal insulation. Polyurethane density must be between the range of 40 (± 2) kg/m3 so that the thermal insulation coefficient is at the desired value and for the carrier characteristics of the panel. It has high dimensional stability. Water absorption is not available, it floats on water. No bacteria grows inside. Its usage performance is good since it has high compressive strength. Usage temperature should be 70-80°C maximum. Maximum resistance temperature is 100-110°C. Above this temperature it loses its characteristics.
Polyisocyanurate (PIR) is formed as a result of the chemical reaction between the PMDI (polymeric methyl diphenyl isocyanate) or MDI and polyol. The amount of the mixture of MDI and polyol components differs polyisocyanurate from polyurethane. The amount of MDI used in PIR production and the amount of the flame retardant catalyst are higher. PIR is composed of isocyanurates chains which have higher chemical stability at high temperatures. PIR's flammability and smoke generation is very low compared to polyurethane. It creates excellent thermal insulation due to its closed cell structure. PIR should be used at maximum 80-90°C. Its maximum resistance temperature is 100-110°C. After this temperatures, it loses its function.
Rockwool is formed by melting the inorganic raw materials (basalt) at 1350°C-1400°C into fiber. No change occurs in size even if it is exposed to moisture and humidity. It does not deteriorate, become mouldy, corrode or rust. Rockwool can not be destroyed by insects and micro-organisms. Rockwool plates are sliced in our fully automated production facility so as to fill in the ribbeds and made perpendicular to the panel surface and thus compression strength of the sandwich panel is increased. Rockwool provides high fire safety as well as heat, noise insulation and acoustic layout.
This insulating sandwich panel has been designed to offer a better sound absorption. Made of a mineral wool core and two prepainted steel facings, its outer facing is plain and its inner facing perforated.
- Cover width: 1 000 mm
- For low hygrometry buildings
- Core made of mineral wool type A1
- Sound reduction index improved thanks to the inside 20 % perforation vaccum
- Standard thickness of facings: External side 0.63 mm/Internal side 0.63 mm
- 7 thicknesses of insulation core available, from 60 to 240 mm
- Visible fixings
Expanded Polystyrene (EPS)
Expanded Polystyrene (EPS) is a petroleum derivative thermoplastic material. It's very small polystyrene beads expand when heated with water vapor. They start to swell up due to the pentane gas and then adhere to each other firmly, and they take the form of the mold they are contained. Pentane gas is replaced by air at the end of this process. This still and dry air trapped in small closed porous particles enables EPS plates have superior thermal insulation properties. The moisture level of the blocks to be used in sandwich panels is reduced below 2% by drying in special furnaces. Then, they are cut in desired thickness. It is the most economical and lightest product among the thermal insulation fillings.
Kraft paper is produced from softwood trees resistant to high moisture, such as pine, fir, spruce with longer fiber by processing with sulfate or alkaline. Kraft means strong in German. Kraft papers are usually produced in dark, ie. natural color. They have high tensile strength and elasticity. Their strength indicator explosion values vary between 3.5-5 kPa and their weight vary between 110-140 g/m2.
In low slope roof systems with a slope under 5%, one side membraned roof panels are used. PVC (polyvinylchloride) and TPO (polyolefin) membranes are insulation membranes that are laminated with reinforced felt layer and welded together with hot air ,resistant to atmospheric conditions and UV. Thanks to the polyester reinforcement, it has a high resistance to tearing and dimensional stability. Reinforced laminated felt layer ensure strong adhesion of membrane to the insulation core and prevent direct contact of membrane with insulation core. It provides fire, heat and water insulation in low sloped roofs.
GRP (Glass Reinforced Fiber)
GRP plates are composed of Glass Fiber Reinforcement and polyester resin. They differ from many other materials due to their properties. GRP (Glass Reinforced Polyester) coating and insulation is a form of superior coating obtained by providing a chemical reaction with the addition of glass fiber mat and a carrier matrix resin (polyester) with high mechanical properties. In addition of the thermal insulation Roof Panels with GRP supplied, also resistant to chemicals and high temperature because of its corrosive properties. GRP material's shape does not change since it is a thermosetting plastic. And, it provides heat resistance between -40°C to + 120°C. It is resistant against impacts and vulnerable to breakage. GRP sheets when used as a substitute for the lower sheet of the roof panels; provide solution to problems such as thermal insulation, hygiene and corrosion, which are frequently encountered in the industrial buildings, chemical production facilities, food plants, manure drying facilities, sports facilities, thermal swimming pools and constructions in the agriculture-livestock sector.
Painted Galvanized Sheet
Painted galvanized steel sheets are hot dip galvanized by continuous process in accordance with EN 10143:2006 standards, with 100-275 gr/m2 zinc-coated. Galvanized coating improves corrosion resistance of the sheet. Due to its hardness, galvanized sheet is resistant to impacts and abrasion. On load bearing layers, galvanized sheet thickness should be minimum 0,50mm.
In sandwich panels, aluminium with a flat or embossed surface is used. It can be used as natural, preservative lacquered or painted. Aluminum's corrosion resistance is a very high. It is light weighted and it is a good conductor. It is preferred in acidic or corrosive environments or under heavy industrial conditions. Since its expansion coefficient is quite higher than the galvanized sheet, its adhesion to the insulating material is weaker. It is not recommended in climatic conditions with night and day high temperature differences.
In sandwich panels, load bearing layer thickness should not be thinner than 0.50 mm and in corrugated sheets, the sheet should not be thinner than 0.70 mm.
Stainless steel is especially preferred in the interior and exterior surfaces of the Cold Storage panel for hygiene because of its acidic environmental durability and corrosion resistance. It is produced in different qualities. Products should be selected by taking only the mechanical and chemical values into consideration. 316,304 and 430 grade stainless steel values in the following table are stated since they are the most frequently requested products on the market.
PVC Laminated Steel
Galvanized and aluminium layer laminated PVC film can be used in indoor or outdoor environments.
With its flat surface, textured and wood patterned alternatives, it offers a wide range of application possibilities. PVC films provide practical and effective usage scope in different sectors with its food safety, non-toxic, non-flamable, UV resistant, hygienic, ease of cleaning and suitable for the mechanical environment
Aluzinc, Zincalume or Galvalume are different names of the same product, which is recently being used in interior and exterior surfaces of the sandwich panel. It consists of 55% Aluminum, 43.4% Zinc and 1.6% Silicone.
Aluzinc is 2-6 times more corrosion resistant than the galvanized sheet due its aluminum and zinc content. Aluminum forms a layer between the steel surface and the atmosphere to obtain protection. This aluminum barrier, i.e. its extremely resistant aluminum oxide coating, does not dissolve in most environments and provides a long-lasting protection against corrosion. However, zinc provides a similar protection with the hot-dip galvanized sheet (e.g. against situations such as when steel comes out in surface layer as a result of possible cuts and scratches). In principle, zinc reacts instead of steel plates as it is referred to as sacrificial cathodic protection. By protective synergy of aluminum and zinc, Aluzinc provides a strength far beyond the protection provided by the aluminum or zinc alone.
Due to its atmospheric corrosion resistant structure, it provides assurance against rots and perforations. It is capable of reflecting solar radiation.
PET (Polyethylene Terephthalate)
Polyethylene terephthalate (PET, PETE, PETP) is a thermoplastic material of the polyester range produced by the poly condensation method. Its softening temperature is approximately between 70 °C - 80 °C. It is not deformed up to this point and it is resistant to breakage. It can reach above 140 °C when it is in the crystal form.
Its melting point is between 235 °C and 260 °C (depending on the degree of crystallization and degree of polymerization). It serves as a barrier against gas and moisture. PET forms the bottom layer of the sandwich roof panels which are used in acidic environments, Food Plants, Chemical Manufacturing Plants, Fertilizer Drying Facilities, Sports Facilities, Thermal Swimming Pools and constructions used in the Agriculture-Livestock Sector.