Insulation. SOLKANE 365 SOLKANE 365/227 Flammability characteristics and handling. Solvay Special Chemicals

Transcription

1 Insulation SOLKANE 365 SOLKANE 365/227 Flammability characteristics and handling Solvay Special Chemicals

2 Introduction Solkane 365mfc has been developed by SOLVAY as a liquid blowing agent for rigid polyurethane foams used in thermal insulation to replace hydrochlorofluorocarbons (HCFCs). Solkane 365mfc has promising environmental figures such as no ODP, a negligible POCP and a low GWP among the HFCs. Solkane 365mfc has a convenient boiling point of 40 C and the lowest gas phase thermal conductivity of all the foreseeable candidates. In current foaming tests the improvement of the insulation quality of the foam is up to 15%, compared to hydrocarbons and up to 30%, compared to all water blown systems. For safety and handling the flammability of blowing agents is one key issue. The flammability characteristic of HFCs depends on the ratio of hydrogen to fluorine. The more hydrogen is substituted by fluorine, the lower the flammability. If the ratio of fluorine to hydrogen is greater than 1, according to our experience, there will be no flash point. Solkane 365mfc has a ratio of 1 and therefore is close to the border between flammable and non flammable substances. Straight Solkane 365mfc unfortunately has a flash point and therefore must be handled as a flammable liquid. Specifically designed blends with different HFCs, notably with Solkane 227ea are non flammable. A blend Solkane 365/227 has no flash point therefore is classified as non flammable, if the amount of 227ea is min. 5%. The present document gives more information about straight Solkane 365mfc and the non flammable blend Solkane 365mfc/227. Table 1: Main characteristics S olkane 365mfc S olkane 365/227 blend Structure CF 3 -CH 2 -CF 2 -CH 3 CF 3 -CH 2 -CF 2 -CH 3 / CF 3 -CHF-CF 3 Ratio 93/7 wt% Molecular weight 148 n.a. Boiling point [ C at 1013 mbar] 40.2 ~30 Density, [kg/dm3 20 C)] Vapour pressure, [bar (@ 20 C)] Vapour thermal conductivity [mw/m K] at 25 C Ignition temperature 594 ~590 Minimum ignition energy at 25 C 10.4 mj NN Flammability limits [% by vol.] Flash point (at C) < -27 C none 2

3 Flammability characteristics of Solkane 365 Solkane 365/Solkane 365/227 Flash point and flammability of the liquid The determination of the flash point of Solkane 365mfc was performed using an Abel Pensky closed cup flash point apparatus, in accordance with DIN T2. A flash point was determined to be below 27 C, which calls for labelling Solkane 365mfc as highly flammable. It must be stressed that the flammability of Solkane 365mfc is less critical than the one of hydrocarbons. The lower flammability limit is significantly higher for Solkane 365mfc than for hydrocarbons, and the heat of combustion is significantly lower. Furthermore, the flammability of Solkane 365mfc has no significant influence on the flammability of the foam itself. The following table gives a survey on important flammability characteristics. Table 2: Flammability characteristics in comparison Blowing Agent Bp.: [ C] LFL* [% v/v] UFL** [mg/l air] UFL** [% v/v] Flashpoint [ C] Minimum Ignition Energy [mj]*** Auto Ignition [ C] Heat of Combustion [kj/kg] Solkane 365mfc 40 3, ,3 < 27 10, Solkane 365/ ~3,6 ~251 ~13 none NN ~ Solkane 141b 32 5, ,7 none ~ Ethanol 78 3, ,4 13 0, n-pentane 36 1,4 45 7,8-56 0, * Lower flammability limit **Upper flammability limit ***at 25 C Minimum ignition energy (MIE) The minimum ignition energy (MIE) is the smallest quantity of energy, capable to ignite a gas or vapour. While not generally required, e.g. under the EC regulations, this is one of the most important criteria of ignition properties and means of appraising the hazard should a material be involved in an accident. Solkane 365mfc has been checked in a vessel of 1 dm³. For Solkane 365mfc the lowest energy required for ignition has been found at a concentration of 8% by volume in air. The minimum energy to ignite the vapour is 10,4 +/- 0,5 mj at 25 C and 4,4 mj at 100 C. For example usual flammable liquids such as pentane have a minimum ignition energy below 1 mj, see table 2. The MIE value of Solkane 365mfc is between that of the extremely flammable hydrocarbons (MIE is 50 times lower) and that of Solkane 141b (MIE is 2000 times higher). Flammability limits in air Air/vapour mixtures have been checked to get the flammability limits in air. Data may depend on the size of the equipment due to surface effects that influence the results of substances standing at the borderline to flammable substances. We measured the flammability limits in air at an independent lab. The determination was performed using an apparatus in accordance with DIN

4 For Solkane 365mfc it has been found that the limit is between 3.6 and 13.3 % by volume in air. A lower flammability limit for Solkane 365mfc of 3.8 % v/v means 251mg/l in air, which is 6 times higher than for Pentane. Summary The above results indicate that straight Solkane 365mfc must be handled as a flammable liquid, even if its risk of flammability is less important, compared to hydrocarbons. Flammable substances are usually labeled with the symbol "F" and the risk phrase "R11 highly flammable". Solkane 365/227, a non flammableblend Introduction Solkane 365mfc is the key component to form a range of promising blowing agent blends. For safety applications a non flammable HFC-blend is of special interest. Solkane 227ea is commercially produced propellant for pharmaceutical aerosols. Blends of Solkane 365mfc and Solkane 227ea have been checked for a flash point using an Abel Pensky closed cup flash point apparatus, in accordance to ISO A blend of Solkane 365/227 with 5 pbw of Solkane 227ea has no flash point and is classified as a non flammable liquid. It has to be pointed out that this blend is non azeotropic, and the compound Solkane 227ea evaporates first during handling. To have a safety margin SOLVAY therefore recommends the blend Solkane 365mfc/227 with 7 pbw of Solkane 227ea. This blend starts boiling at ~30 C. Flammability limits in air Although the blend Solkane 365/227 has no flash point, it has flammability limits in air. Such a situation is well known with for instance Solkane 141b. The flammability limits in air are nearly the same as for straight Solkane 365mfc ( % by volume). Vapour pressure 5,0 Vapour pressure [bar, abs.] 4,5 Solkane 365mfc 4,0 3,5 Solkane 227ea 3,0 2,5 Solkane 365/227 2,0 1,5 1,0 0,5 0, Temperature [ C]

5 Safety precautions for handling Safety precautions for handling As Solkane 365/227 is a blend, there is a different behaviour compared to Solkane 141b in terms of storage and handling, and it is necessary to clarify a few details regarding its safety status. Due to its non azeotropic character and the difference in boiling points (figure 1) and due to the fact that the non flammable component of the blend is the most volatile, the blend might become flammable, if a significant fractionation is allowed to take place. As the non flammable component Solkane 227ea evaporates first, the liquid would enrich in flammable Solkane 365mfc. Therefore the material should only be stored in tight systems. The drums should be protected from physical damage or excessive heat. The drums should not be left open and should be tightly closed after use. Based on general experience Solkane 365/227 should not be mixed with either air or oxygen under pressure, particularly if an ignition source is present. If pressurization is required in your application, nitrogen must be used. If one vessel containing Solkane 365/227 is left inadvertently open, or if the blend is spilled by accident, Solkane 227ea will evaporate first. After some time the remaining liquid will become flammable, due to the reduction of the Solkane 227ea concentration. Therefore care should be exercised when working with this blend, and the concerned workers must be informed and trained accordingly. Behaviour in a closed storage tank The difference in boiling points between Solkane 365mfc (40 C) and Solkane 227ea ( C) may suggest that an important fractionation is taking place between the liquid and the gas phase, when emptying a storage tank from the liquid phase. Calculations using the known thermodynamic properties of both Solkane 365mfc and Solkane 227ea have shown that this is not the case. It demonstrates that the concentration of Solkane 227ea is reduced less than 1%, e.g. from a ratio of 93/7 to 94/6. The gas phase of the storage tank contains gradually slightly more Solkane 227ea, which rules out that the overall content of the storage tank becomes flammable over time or after several refilling. 5

6 Change of composition during emptying the blend 93/7 from a closed system Mass fraction 227-ea in the liquid phase 0,071 0,070 0,069 0,068 0,067 0,066 0,065 0,064 0,063 0, C 30 C 0, ,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 Volume liquid / volume tank 6

7 Guide for Storage and Handling Solkane 365 Solkane 365mfc is labeled as highly flammable and therefore is a hazardous substance. The flammability limits in air are advantageously high, compared to hydrocarbons, and are % v/v in air. Solkane 365mfc must be kept away from sources of ignition, such as flames or hot surfaces with a temperature of 580 C or higher or electrical sparks. The following recommendations apply: Handling - Operate in a well-ventilated area. - Prevent any product decomposition from contacting hot spots. - Keep away from ignition and heat sources. - Do not mix the blend with air or oxygen, particularly if an ignition source is present. - Use Nitrogen if pressurisation is needed. Storage - In a ventilated, cool area. - Keep away from ignition and heat sources. Other precautions - No open flames or sparks, no smoking. - Provide electrical equipment safe for hazardous locations. - Grounded equipment. Non flammable blend Solkane 365/227 The blend Solkane 365/227 (93/7) has no flash point. Due to its non azeotropic character the blend might become flammable again during handling, e.g. if Solkane 227ea is allowed to evaporate from the blend, and if its concentration decreases from 7 wt-% below 5 wt-%. To avoid this some handling precautions must be followed: Handling - Do not keep open any vessel, drum or other container and keep it well closed to avoid that Solkane 227ea evaporates. - Operate in a well-ventilated area. - Do not mix the blend with air or oxygen, particularly if an ignition source is present. - Use Nitrogen if pressurisation is needed. Storage - In a ventilated, cool area. - Keep away from excessive heat or direct sunlight. - Protect drums from physical damage. Other precautions - If the blend is spilled, the liquid will become flammable and must be handled as straight Solkane 365mfc. - No open flames or sparks, no smoking. 7

8 35/248/12.12/007/pdf For technical or sales information please refer to Solvay Fluor GmbH Postfach Hannover Germany Phone Fax Solvay (Shanghai) Co. Ltd. Zhang Jiang Hi-Tech Park Building 7, No.899, Zu Chong Zhi Rd Shanghai , P.R. China Phone Fax Solvay Fluorides LLC 3333 Richmond Avenue Houston, Texas USA Phone Fax Disclaimer: The use of SOLKANE 365mfc and of blends containing SOLKANE 365mfc might fall within the scope of U.S. patent no. 5,496,866. The following must be noted regarding the USA (until March 5, 2013): (1) SOLKANE 365mfc cannot be used in the USA, by itself or in a blend, as a blowing agent to foam a plastic based on an isocyanate to form plastic foam compositions; (2) SOLKANE 365mfc and blends containing SOLKANE 365mfc must not be made, used, offered for sale, or sold in the USA, or imported into the USA, for such blowing uses; and (3) closed cell plastic foam compositions prepared by foaming a plastic material based on isocyanate in the presence of a propellant comprising SOLKANE 365mfc and/or a blend containing SOLKANE 365mfc, cannot be made, used, offered for sale, or sold, within the USA, or imported into the USA. To do so can result in a claim of patent infringement under U.S. patent no. 5,496,866. Solvay will not sell SOLKANE 365mfc or blends containing SOLKANE 365mfc to any purchaser intending to use the product accordingly. 8