Flame-Retardants for HIPS

Transcription

1 Flame-Retardants for HIPS General Application Data about Flame-Retardants for High Impact Polystyrene (HIPS) Fire-Safety HIPS is playing a very important part in the electronics industry. It is used mainly for the production of housings of equipments such as television sets, audio-videos and personal computers. As it burns easily, it has become a real threat to users and it has been necessary to improve significantly its fire retardancy. This has been achieved mainly by the use of brominated fire retardants employing antimony trioxide as a synergist. Brominated fire retardants may be considered as cornerstones to provide safety against the danger of fire. This is shown very clearly in the published fire statistics of European made television during the nineties when TV housings were not protected against external ignition. Unlike safer US made TV sets in which brominated fire retardants are often used, housings of European TVs at that time were usually produced without any flame retardant. This may explain the sharp difference between fire statistics in the US and in European countries (see Figure 1).

2 TV causing fire per million TV peryear Caring for your Future-Today! Figure 1: TV fire statistics Europe IEC 65 HB 5 USA UL 94 V- But since July 21, to cope with this serious lack of fire safety, the CENELEC added in the safety standard for TV sets a requirement to have their housing withstanding against external ignition. ICL IP FRs product line This data sheet provides preliminary information on the preparation of FR HIPS. An FR system is always better introduced as a masterbatch concentrate in order to improve its dispersion and its efficiency. Usually masterbatch concentrates will contain circa 7-8% of FR's including antimony oxide and the carrier is selected to achieve optimal compatibility with the polymeric matrix. For HIPS, HIPS/PS, acrylate copolymers, SBR or Kraton type of copolymers can be used. The type of HIPS may have a considerable influence on the properties such as impact and heat distortion temperatures. ICL IP is offering a broad line of Flame-Retardants (FRs) and tailor-made solutions that provide additional benefits in new markets and applications. The following FRs are particularly suitable for FR HIPS passing class V- according to the UL 94 standard:

3 FR-141 (decabromodiphenyl ethane - 82% bromine) is cost efficient in HIPS but has poor UV stability and is not melt blendable during injection molding FR-245 [Tris(tribromophenyl) cyanurate - 67% bromine], a joint development between the Japanese Company Dai-Ichi Kogyo Seiyaku (DKS) and ICL IP, offers at an attractive cost an optimal balance of needed properties: high melt flow during injection molding excellent light stability good impact properties high heat distortion temperature (HDT) F-3 series (modified brominated epoxy oligomers-mbeo with 55-58% bromine) combines good to excellent UV stability with good melt flow properties during injection molding but suffers from limited impact properties. In addition to the previous list, a second series of FRs are also offered by ICL IP but only for application where less severe fire retardancy is acceptable such as class V-2 (UL- 94): FR-72 [bis (2,3-dibromopropyl ether) of TBBA 67% bromine] includes 33.5% more FR efficient aliphatic bromine, is melt blendable with an optimal thermal stability and is cost efficient. FR-37 [tris(tribromoneopentyl) phosphate 7% bromine + 3% phosphorus] is offered for applications including exposed sections which require light stability, brightness, good initial colors and impact. All these FRs have undergone extensive toxicological and environmental testing and have been proven to pose no risk to health and environment. Detailed application data sheets of these FRs in HIPS are available from website.

4 Thermal stability Thermogravimetric analysis of the above mentioned flame-retardants (Table 1) reflects their suitable thermal stability enabling high to fairly high processing temperatures. Table 1: Thermogravimetric analysis (TGA-1 C/min in air) Temperature, C FR Type FR-141 FR-245 F-314 FR-72 FR-37 Weight loss, % Processing conditions Typical processing conditions to compound and mold HIPS flame retarded with these FRs are as follows: Compounding Compounding in a co-rotating twin-screw extruder (L/D: 32) Temperature profile, C: Screw speed, rpm: 3

5 Injection molding Temperature profile, C: Mold temperature, C: 4 Pressures, Bar: Injection 13 Holding 75 Back 2 Cycle time, sec 15 FR efficiency Table 2 gives indicative guidance to define formulations able to pass class V- and V- 2 according to UL94. Table 2: Guidance for FR HIPS class V- and V-2 Class Thickness mm Bromine content, % Antimony trioxide content, % V- 3.2 Aromatic Br: Aromatic Br: V-2 3.2/1.6 Aliphatic Br: Aromatic Br: It must be noted that only fully aromatic bromine containing FRs are suitable to

6 Total burning time sec Caring for your Future-Today! produce UL-94 class V- compounds. For FR-HIPS class V-2, aliphatic bromine FRs are signififcantly more efficient than aromatic bromine ones. Figure 1 shows the shorter total burning times achievable with aliphatic bromine FRs. Usually, FR HIPS class V-2 are expected to pass also the "Glow wire Test" at 96 C according to the standard IEC For high flow grade of HIPS, it is recommended to use FR systems based on SaFRon 55 Antidrip series. The enhanced efficiency of SaFRon 55 series allows reducing significantly the quantity of FRs (Brominated FR + antimony trioxide). For more details, please contact ICL IP Tecnet Representative. Fig. 2: Aliphatic versus aromatic bromine in HIPS (UL mm) 3 2 Aliphatic Aromatic Br content, w% Properties overview Table 3 and 4 provide guidelines to choose an optimal FR for HIPS applications passing class V- or V-2 respectively.

7 Table 3: Properties of V- HIPS FR-141 FR-245 F-3 Properties Thermal stability series Melt flow FR efficiency Impact UV/light stability Heat distortion temperature Non-blooming Cost efficiency Properties = good = very good = excellent Table 4: Properties of V2 HIPS FR-72 FR-37 FR-141 FR-245 Thermal stab. Melt flow FR efficiency Impact UV/light stab. HDT Non-blooming Cost efficiency

8 Melt-Flow

9 MFI - g/1min MFI - g/1min Caring for your Future-Today! Figure 3: Melt flow properties in FR HIPS V- 18 F FR Ref no FR FR-141 Figure 4: Melt flow properties in FR HIPS V-2 FR-72/F FR-245 FR-37 8 FR Ref. no FR 4 2

10 FR-72, F-3 series, FR-245, and FR-37 enhance flow during injection molding as they melt during the process. The comparative values of MFI of various flameretarded HIPS shown in Figures 3 and 4 explain why, compared with FR-141, these FRs permit shorter cycle times and thinner walls of processed articles. Impact properties As shown in Figures 5 and 6, better impact properties are achieved with following FRs: For V-: FR-141 and FR-245 For V-2: FR-72, FR-37, FR-141 and FR-245 Figure 5: Izod notched in FR HIPS V J/m FR-141 F-314 FR-245 Ref. no FR

11 kg.cm Caring for your Future-Today! Figure 6: Gardner impact in FR HIPS V Ref no FR FR-245 FR-141 F-314 Figure 7:Izod notched in FR HIPS V J/m FR-141 F-314 FR-245 Ref no FR FR-37 FR-72

12 Delta E Caring for your Future-Today! UV/Light Stability As shown in Figure 8, following FRs are recommended for UV stable applications: For V-: FR-245 and F-3 series For V-2: FR-37, FR-72, as well as FR-245 and F-3 series. Health Safety - Environmental aspects ICL IP FRs product line has undergone extensive toxicological and environmental testing 1, and has been proven to pose no risk to health and the environment. Figure 8: UV stability Xenotest - 3h in FR HIPS (ASTM D ) FR-37 FR-72 FR-245/F-314 FR-141 For instance, results of analyses performed by Institut Fresenius Chemische und Biologische Laboratorien GmbH on ICL IP FRs product line itself and under conditions simulating a modern municipal solid waste incinerator for presence of polybrominated dibenzo-para-dioxins/dibenzofurans (PBDD/PBDF), have shown it to 1 Further information available upon request

13 be in full compliance with the requirements of the global most strict criteria of the German Dioxin Ordinance and EPA TSCA Final Rule requirements 1. A life-cycle assessment (LCA) study completed in Sweden 2 has found that over the lifetime of a television set, there are less emissions to the environment from a TV set containing previously widely used decabromodiphenyl oxide in the outer casing, than a TV set without such flame retardant protection. The study found that the televisions with flame-retarded enclosures had less impact on the environment. Because fires themselves are a major source of polyaromatic hydrocarbons (PAHs), a class of carcinogenic substances found in combustion smoke, and dibenzodioxins and furans, the use of flame retardants significantly decreases environmental emissions of this type. As part of an ongoing Product Stewardship Program and Customer oriented policy, ICL IP is committed to implement further toxicological and environmental tests if needed. Recyclability Studies completed in Germany have demonstrated that HIPS containing brominated flame retardant is fully recyclable, with the flame retardant able to withstand at least five cycles. The studies analysed both the possible degradation of the flame retardant, and also compliance with the tightest dioxin emissions standards during the recycling process. The studies were commissioned by BSEF, and conducted by the highly esteemed GfA laboratory and the University of Erlangen in Germany. The analytical work was carried out under the supervision of GfA's Dr Stephan Hamm 3. 2 LCA Study of Flame Retardants in TV Enclosures, Presented to Flame Retardants 2 Conference, Margaret Simonson, SP, P.O. Box 857, S-51, 15 Boras, Sweden and Hakan Stripple, SP P.O. Box 4786, S-42 58, Goethenborg, Sweden, February 2. 3 Further information available upon request

14 Applications Recommended applications of fire retarded HIPS and its alloys are: housing of electronic devices such as TV (see figure below), audio and video equipment, remote control and mobile phone.

15 For further advice and assistance, contact our representatives in your area: Head Office ICL-IP Ltd. Phone: Fax: frinfo@icl-ip.com North America and Mexico ICL-IP America Inc. Asia Pacific China Phone: ICL China Fax: fr.nam@icl-ip.com Phone: Fax: South America fr.china@icl-ip.com ICL Brasil Ltda Japan Phone: ICL-IP Japan Ltd Fax: fr.sam@icl-ip.com Phone: Fax: Europe fr.japan@icl-ip.com Main Office Asia Pacific ICL-IP Europe B. V. ICL Asia Ltd Phone: Fax: Phone: fr.europe@icl-ip.com Fax: fr.asia@icl-ip.com Italy Other Parts of the World PM Chemicals Italy ICL-IP Sales Office Phone: Fax: Phone: fr.it@icl-ip.com Fax: fr.row@icl-ip.com Tecnet 1273