Use of Rigid Polyurethane Foam in Refrigerators and the New KIMCool Family

Turkey is one of the world's most important players in the white goods sector. After China, which accounts for half of global production, Turkey ranks first in Europe and second globally with approximately 26 million units of the highest production volume. It has surpassed Germany and Italy, which were previously known as production bases in this field. Globally, Turkey is followed by Brazil, the United States and Poland. Initial white goods production took place in the 1950s, and today the sector ranks among the locomotive sectors of the Turkish economy through its advanced technology, innovative structure, export revenues generated and employment created. [2] In 2016, white goods production in Turkey increased by 6.8% compared to the previous year, reaching 26.2 million units. In the sector, 75% of production is exported to approximately 150 countries, with EU countries being the most important export market for the sector. In the sector's growth, increasing urbanization in Turkey, a young population and activity in the construction sector, as well as developments in export markets, particularly among EU countries, play a role. [1]

Chart 1: White Goods Production in Turkey by Year [1]

As can be seen from the table below, in 2016 refrigerator production is the second most produced white good after washing machines, with production close to 7 million units within the white goods sector. It represents approximately 27% of all white goods produced.

Table 1: 2016 Production Units by Product Type in the White Goods Sector [1]

Rising production volumes and the increasing importance of energy consumption day by day have also increased expectations for the performance of polyurethane foam, which is primarily used as insulation within refrigerators. The best way to meet increasing production volumes without additional investment is specialized polyurethane systems that enable rapid production. Furthermore, in today's environment where raw material prices have increased significantly, expectations are growing for the development of systems that increase foam strength and dimensional stability, thereby providing weight savings. In addition, energy classification in refrigerators is becoming increasingly important with each passing year. In the past, insulation in refrigerator production was provided using materials such as EPS or mineral wool. Since the 1960s, polyurethane foam has become the dominant insulation material used in refrigerator production due to the unique advantages it provides. Both its significantly lower thermal conductivity coefficient compared to its counterparts and its increased productivity have made it indispensable in this sector. Until recently, blowing agents such as CFC-11 or 141b, which had negative effects on global warming and damaged the ozone layer, were used in polyurethane foams. Today, pentane and its isomers (HC) are the most commonly used blowing agents in the refrigerator polyurethane insulation sector. The first energy classification for refrigerators and freezers was created in 1995. Subsequently, sales of low-efficiency, high-energy-consuming cabinets within Europe were banned year after year, and higher energy efficiency classes such as A++, A+++ were added. Today, across all of Europe, sales of cabinets below A+ level are prohibited in stores.

Table 2: Evolution of Energy Classifications Over Time [3]

Energy classification is performed according to EEI (Energy Efficiency Index) value, and the final product is labeled as follows. [4]

Figure 1: Example and Classification for Refrigerator [4]

As can be understood from the chart, when examining refrigerator sales within the European Union, although the market is dominated by A+ today, sales of refrigerators with higher energy efficiency such as A++ and A+++ show a significant increase with each passing year.

Chart 2: Refrigerator Sales Volumes by EU Energy Class [3]

A refrigerator's energy consumption can be improved by improving heat insulation, using more efficient compressors, precision temperature control systems or design. This is where work on polyurethane is concentrated to improve heat insulation. Properties of polyurethane foam such as the blowing agent used within it, cell diameter and polymer structure are determining factors for insulation. Although trends and expectations vary by country or region, today the use of environmentally friendly refrigerant gases and blowing agents, energy efficiency, health awareness, hygiene and freshness, visual design of products and low cost are important expectations. As Kimteks Polyurethane, taking into account all trends and customer expectations, we have developed the KIMcool family for the refrigerator sector. Refrigerators produced with KIMcool systems have maximum mechanical strength and excellent dimensional stability. With a catalyst package specially designed taking into account production speed, they have the ability to cure very quickly. This makes it possible to shorten existing mold opening times and increase production capacity. In addition, the base polyols in its composition are compatible with both cyclo and iso pentane. This makes it suitable for use with cyclopentane 70 or cyclopentane 95. Material blown with cyclopentane 95 provides excellent insulation with a thermal conductivity coefficient of 20.5 mW/mK at an average temperature of 24°C. Beyond all this, thanks to its very good flow characteristics, it is possible to obtain refrigerators with smoother surfaces with minimal air voids and without undulation on side surfaces. With an average closed cell content close to 95% and a high cross-linking ratio, it maintains dimensional stability in hot and cold environments. Emrah Akbaş / Research and Development Director / Kimpur-Kimteks Polyurethane Inc. References 1.General Directorate of Exports (2017) Republic of Turkey Ministry of Economy. 2.Öztürk, A.B. (2016) White Goods Sector Economic Research Department. 3.Michel A., Attali S., Bush E. (2015) Energy efficiency of White Goods in Europe: monitoring the market with sales data. 4.Hierzinger, R. and Krivošík J. (2012) Comparison of energy efficiency requirements of the energy labels and ecodesign legislations.