for Polymers Industry Information 0403 Focused. I nnovative. R esponsive.

Transcription

1 Carbon Black Pigments for Polymers Industry Information 0403 Focused. I nnovative. R esponsive.

2 1. Introduction Orion Engineered Carbons is a leading global manufacturer of Carbon Blacks for pigment and rubber applications. Production sites and applied technology centers can be found in all regions of the world. Orion Engineered Carbons is selling Carbon Black Pigments under many brand names such as PRINTEX, AROSPERSE, HIBLACK, NEROX, NIPex, COLOUR BLACK, SPECIAL BLACK, LAMP BLACK and PANTHER. Our Carbon Black Pigments offer an excellent balance of colorimetric properties, dispersibility, UV-protection, infrared absorption, electrical conductivity and adjustment of mechanical and rheological properties. 2. Benefits Tailor-made portfolio Consistent quality Optimized performance Efficient consulting Carbon Black Pigments are used in Polymers for their colorimetric properties and also to extend the life span of those Polymer materials that possess limited resistance to light and weathering. Table 1 provides an overview of Carbon Black Pigments for Polymers together with their suggested applications. Carbon Black Pigments are suitable for a broad range of application areas that include: pipes for drinking and waste water fibres for textiles films for packaging of food or agricultural films thermal insulation panels semiconductor shields and protective layers of high voltage cables engineered Polymers for automotive parts adhesive & sealants for automotive windshields and glazing for the construction industry Scanning electron microscopy micrograph of a typical Carbon Black Pigment 2

3 Table 1 Selection of Carbon Black Pigments designed for the Polymer industry Selected Polymers Typical applications Polyolefines PE, PP, Copo BioPolymers PLA Styrene Polymers PS, SAN, ABS, ASA Polyamides PA6, PA6.6, PA12 Polyesters PET, PBT Polyvinylchlorides PVC-P, PVC-U Engineered Polymers PMMA, PC, Blends Thermosets UP, EP Insulation & foams EPS, PUR, PP, PE Wire & cables PE-Copo Pipes PE, PP, PA, PVC Films PE, PP, Copo, PVC Fibres PET, PA, PP Adhesive & sealants PUR, PIB, polysulfide, silicons, MS Polymers Masterbatches & compounds COLOUR BLACK FW 200 COLOUR BLACK FW 1 COLOUR BLACK FW 18 SPECIAL BLACK 4 PRINTEX U PRINTEX V PRINTEX 95 PRINTEX 90 PRINTEX 85 HIBLACK 600 L PRINTEX 80 PRINTEX 75 AROSPERSE 11 AROSPERSE 138 AROSPERSE 26 PRINTEX alpha, alpha-a PRINTEX P, P-A PRINTEX 60 PRINTEX 60-A PRINTEX HV HIBLACK 430 H PRINTEX L6 PRINTEX L HIBLACK 40B2 PRINTEX 300 PRINTEX 30 PRINTEX 3 PRINTEX 25 PRINTEX A PRINTEX G SPECIAL BLACK 100 LAMP BLACK 101 AROSPERSE 15 PRINTEX XE2-B PRINTEX Nature Jet black coloring Coloring Tinting Conductivity Stabilizing Reinforcement / Rheology 3

4 3. Carbon Black Pigments for coloring Carbon Black lack Pigments additions of % are usually sufficient for the black lack coloring of Polymers. Higher addition levels, however, may be necessary in those Polymer materials possessing their own inherent color (e. g. ABS). The correlation when reducing a Carbon Black lack Pigment with a white pigment (grey tones) is the same with those obtained when viewing a film with transmitted light. For example, coarse, highly structured Carbon Black lack Pigments result in a grey color with a blue tint when used for tinting. Technical terms, such as jetness, tinting strength and undertone, are frequently used when describing the coloring of Polymers with Carbon Black lack Pigments and are briefly defined as follows: Figure 1 summarizes the effects of primary particle size and structure on Carbon Black lack Pigments jetness, tinting strength and undertone. In this context, the dispersibility of Carbon Black lack PigA Carbon Black lack Pigment s jetness is the intensity of the black lack color ments is an important characteristic, as briefly explained below. achieved with that particular grade. The lower the light reflection from a material colored with a Carbon Black lack Pigment, the higher Figure 1 its jetness. The effects of the primary particle size and structure of Carbon Black Pigments on jetness, tinting strength and undertone in Polymers The tinting strength of a Carbon Black lack Pigment describes its ability to tone down other coloring components or to mask them with black lack coloring. If a given color shade (white or colored) is slightly darkened by adding a Carbon Black lack Pigment, it is called tinting. When pigmenting Polymers with Carbon Black lack Pigments, a definite undertone develops in addition to the black lack color. This can be either brownish or bluish depending on the type of Carbon Black Pigment used. However, one has to distinguish between the visual assessments of a black lack pigmentation in masstone when seen from above or when viewed through a transparent section. A Carbon Black lack Pigment s jetness and also, in theory, its tinting strength, increases with decreasing primary particle size and structure. Masstones of fine particle sized Carbon Black lack Pigments display a blue undertone when viewed from above, which further reinforces a visual perception of high jetness. The undertone is also influenced by the structure of a Carbon Black lack Pigment. In this case, low structure among equally fine Carbon Black lack Pigments has the effect of producing a bluer undertone. Highly structured Carbon Black lack Pigments, with a coarse particle size, develop a black lack color with a brownish undertone. The correlation between undertone and the other parameters is reversed when a color in masstone (e. g. a semi-transparent film) is viewed with transmitted light, in comparison to when the visual assessment is made with impinging light. When viewed transmitted light, films appear to become browner with decreasing Carbon Black lack Pigment particle size and structure, whereas coarse, highly structured Carbon Black lack Pigments show bluer undertones in these circumstances. 4 Primary particle size fine coarse Primary aggregates low structure high structure Masstone high jetness low blue undertone brown high tinting strenght low brown undertone blue difficult Dispersibility easy Tinting

5 Effective dispersion is essential to achieve the optimum jetness and tinting strength of a Carbon Black Pigment, i. e. the Carbon Black Pigment agglomerates (accumulation of aggregates) should, in effect, be completely broken down. Agglomerates, which are not sufficiently broken down, act, from an optical point of view, in the same way as aggregates of similar size. The dispersion of Carbon Black Pigments becomes increa singly difficult with finer particle sizes and lower structure. In addition, transportation requirements of Carbon Black Pigment can not be ignored even when dispersibility is concerned. Whilst beaded blacks possess clear transport and handling advantages (higher bulk density, lower dust levels, easier dosing etc.), they are, however, more difficult to disperse. Fluffy blacks should, therefore, be selected for those Polymer systems, where only a limited degree of shear is normally used (e. g. in coloring of PVC-P, liquid Polymer ingredients like softeners). 5

6 4. UV stabilization of Polymers UV stabilization is an important application for Carbon Black Pigments in the Polymers industry. Polymer materials, which are exposed to direct sunlight, can be effectively protected from photo-oxidative degradation by Carbon Black Pigments due to their excellent light absorption. Carbon Black Pigments have several functions in this respect: Figure 3 UV protection of polypropylene with Carbon Black Pigments (Microtome section after 3,500 h in the xenon test) They shield the Polymer surface from radiation over a wide range of wavelengths They convert light energy into thermal energy They act as a stabilizer by trapping free radicals The UV protection efficiency of Carbon Black Pigments depends on the particular grade and it increases with higher concentration of Carbon Black Pigment. LAMP BLACK % 1.5 % 1.0 % 0.5 % Figure 2 illustrates the UV protection effect of Carbon Black Pig- ments with respective primary particle sizes. Figure 2 Weathering test on PE-HD with 1 % Carbon Black Pigments Elongation at break in % Time in hours Primary particle size: fine mid sized coarse without Carbon Black Pigments The influence of the Carbon Black Pigment concentration on the UV stability of PP can be seen in Figure 3. In this case, the depth of damage was measured in a vertical cross-section taken from the surface exposed to radiation. Polyolefins in particular are damaged by UV light. Tests on polyethylene have shown that complete UV protection is virtually achieved when using a 2 % loading level of a sufficiently fine particle sized Carbon Black Pigment. The upper addition level is usually around 2.5 %, after allowing a safety margin. This limited addition of Carbon Black Pigment also meets the various European regulations governing the use of Carbon Black Pigments in food contact application and does not significantly affect other Polymer properties, e. g. mechanical properties. PRINTEX P Carbon Black Pigments with small particle size and good dispersibility are the most suitable UV stabilizers. Highly structured, medium particle sized Furnace Carbon Blacks, such as PRINTEX P, PRINTEX alpha and PRINTEX 60, fully meet both requirements. Figure 4 Elongation at break of PE-LD foils with 2.5 % PRINTEX P after external weathering Elongation at break in % PRINTEX P External weathering (years) Without Carbon Black Pigment 6

7 5. Electrical conductivity of Polymers The use of Carbon Black Pigments, i.e. Conductive Blacks, is to impart conductivity and anti-static properties to Polymers. Polymer materials generally possess good insulation pro perties. Their electrical properties remain unchanged at loadings required for Pigmentation or UV-Protection. Once a certain concentration of Carbon Black Pigments is exceeded, the resistivity drops drastically by several units to the power of 10 (Percolation). After Percolation the resistance continues to decline slower with increasing Carbon Black Pigment concentration. Carbon Black Pigments i. e. Conductive Blacks PRINTEX HV, PRINTEX alpha-a, PRINTEX L, PRINTEX L 6, HIBLACK 40 B2 and PRINTEX XE2-B are recommended for modifying the antistatic and electrical conductivity characteristics of Polymers. The required level of Carbon Black Pigments is depending on the type of Conductive Black used in the Polymer system, the processing method and the requirements which have to be met. Conductive Polymer materials are used for packaging of sensitive electronic compondents, such as cable compounds for conductor shielding and jacketing, in floor coverings, carpet backings, conveyor belts, air conduits and in injection hoses for explosives. Figures 5 and 6 demonstrate the influence of the Polymer type used on the resistance properties of Polymer systems containing Carbon Black Pigments. Figure 5 The influence of the Carbon Black Pigments content on the electrical resistivity of Polymers Specific volume resistivity in Ohm* cm PRINTEX L in % Polyethylene - LD Polyethylene - HD Polypropylene 7

8 Figure 6 The influence of Carbon Black Pigments content on the electrical resistivity of Polymers Table 2 Influence of processing methods on the electrical resistance of a finished product (Carbon Black Pigment in Polymer compound) Process Specific resitivity [Ω cm] Sheet pressing < 10 2 Extrusion Injection moulding Film blowing Specific volume resistivity in Ohm* cm PRINTEX L in % Table 3 Influence of cooling speed on the electrical resistance (pressed sheet) Polymer Carbon Black content Specific resitivity [Ω cm] fast very slow PP 10 % Conductive black PP 4 % Extra conductive black PP 3 % Extra conductive black PVC-P 20 % Conductive black PS ABS PVC-P The percolation curves, representing the electrical resistance, vary with the type of Polymer. Different processing methods can lead to substantial variations in the electrical resistance of the finished products (Table 2). The reasons for this are orientation pheno mena and shear. Important factors are the flow and cooling conditions (see Table 3) as well as the material thickness of the finished product. 8

9 6. Reinforcement and rheological control Carbon Black Pigments are in addition an important additive (ingredient) for the modification of the rheological and reinforcing properties especially in the Adhesives & Sealants industrie. PRINTEX Carbon Black Pigments are used particularly in the automotive industry in high-tech windshield adhesives, e.g. polyurethane based adhesive systems. They provide an excellent sag resistance and make the adhesive particularly stable and facilitate its application. An additional field of importance in adhesive and sealants can be observed in the construction industry, e.g. for glazing. Polyisbutylene adhesives and polysulfide based sealants are commonly applied and rheologicaly modified by Carbon Black Pigments. PRINTEX or SPECIAL BLACK grades from Orion Engineered Carbons are used wherever adhesives or sealants are required to be especially UV stable or where jet-black coloring of systems is required. Thixotropy performance of Carbon Black Pigments Viscosity [Pa s] Time [s] 20% PRINTEX in Polyol/Plasticizer High shear rate Excellent thixotropy High and quick viscosity decrease at higher shear rates Fast and perfect viscosity recovery after strain From the broad range of our Carbon Black Pigments it can be selected in dependency of the final requirements of the product performance in the respective adhesive and sealants system. Typical requirements are: thickening performance conductive behaviour (conductive or insulating) UV-protection moisture content drying behaviour enhanced dispersibility shelf live (storage stability) 9

10 Most common Carbon Black Pigments grades in adhesives & sealants Adhesive & sealant system Polyurethane windshield adhesives Recommended Carbon Black PRINTEX 3 PRINTEX 30 PRINTEX 60 PRINTEX 80 PRINTEX U Polyurethane primers SPECIAL BLACK 100 SPECIAL BLACK 250 Polyurethane sealants PRINTEX 3 PRINTEX 30 PVC & PMMA body saler plastisols PRINTEX 60 PRINTEX U Polysulfide & polyisobutylene sealants PRINTEX 300 PRINTEX 30 Electrically conductive adhesives & sealants PRINTEX XE2-B PRINTEX L 6 PRINTEX L 10

11 Benefits Carbon Black Pigments in polyurethane formulations Carbon Black Benefits in PU-Formulations PRINTEX 3 PRINTEX 30 PRINTEX 60 PRINTEX 80 PRINTEX U PRINTEX XE2-B High thickening, low moisture absorption, good dispersibility, UV-Protection Thickening, Low moisture absorption, UV-Protection Excellent thickening & sag resistance, good UV-Protection Superior thickening, excellent UV-Protection High thickening, UV-Protection and less electrical conductivity High electrical conductivity, very high thickening and excellent sag resistance 11

12 Focused. I nnovative. R esponsive. The Americas Orion Engineered Carbons LLC 4501 Magnolia Cove Drive Suite 106 Kingwood, TX USA phone fax Americas-Pigments@orioncarbons.com Europe / Middle East / Africa Orion Engineered Carbons GmbH Hahnstraße Frankfurt am Main Germany phone fax EMEA-Pigments@orioncarbons.com Asia Pacific Orion Engineered Carbons Trading (Shanghai) Co., Ltd. Room BM InterContinental Business Center 100 Yutong Road Shanghai, China phone APAC-Pigments@orioncarbons.com All information and statements contained herein are believed to be accurate. Orion Engineered Carbons GmbH, its agents and/or affiliates composed the information and statements to the best of their respective knowledge. However, the information and statements contained herein shall not be construed as a license or recommendation for use. All sales are subject to Orion Engineered Carbon GmbH Standard Terms and Conditions of Sale, including but not limited to the limited warranty of such Orion Engineered Carbon GmbH Standard Terms and Conditions of Sale. The information and statements contained herein do not amplify, extend, or broaden the liability of Orion Engineered Carbons GmbH, its agents and/or affiliates under the Orion Engineered Carbon GmbH Standard Terms and Conditions of Sale in any way. To prevent damages or infringement of any proprietary right, the customer has to check any and all information before using or applying it Orion Engineered Carbons GmbH OEC-II / 2012