Exploring opportunities for increased
customer value in the automotive brake
pad industry
A case study on adhesion improvement of Twaron pulp
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Exploring opportunities for increased
customer value in the automotive brake
pad industry
A case study on adhesion improvement of Twaron Pulp
Author: Ing. K. Koopman
Student number: 1919806
Address: Eendrachtsplein 10 8355DL Giethoorn Telephone: 06-15095133
Email: koenkoopman@hotmail.com
Period: May – November 2011
Supervisor: Dr. Ir. W. Nijhuis Address: Teijin Aramid B.V.
Velperweg 76 6824 BM Arnhem Telephone: 088-2689371
Email: Walter.nijhuis@teijinaramid.com
1st supervisor: Prof. Dr. A.A. Broekhuis 2nd supervisor: H. van der Meulen (MSc) Address: Faculty Economics and Business
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Management summary
This paper is dedicated to explore market opportunities and technical possibilities for adhesion improvement of Twaron pulp towards phenolic resins and friction formulations. Teijin Aramid’s business strategy is to increase customer value by offering specialized products and expand the revenue in the brake pad industry. One idea is to develop a new Twaron pulp product with increased adhesion properties towards phenolic resins, which should lead to significant functional benefits to brake pad manufacturers. The following research question was stated:
What are the possibilities for adhesion improvement of aramid pulp, and shall this result in increased customer value and a competitive advantage for Teijin Aramid in the friction
materials market?
The paper handles adhesion improvement from a technical marketing perspective, exploring both possibilities chemically on molecular scale and aligns the research idea with current market trends in the automotive brake pad industry. Besides that, it identifies quantification methods of adhesion improvement, explores functional benefits for brake pad manufacturers and handles technology options.
Market research showed that legislation and comfort are the main drivers for innovation in the brake pad industry. Electric and hybrid vehicles are causing a technology shift in braking principles with the introduction of regenerative braking, another important driver for innovation. A PEST and SWOT analysis showed the characteristics of Teijin in the current market, with customer support and high prices as strengths and weaknesses, respectively. Opportunities are in lightweight, comfort, and environmental impact of brake pads. Threats are reduction of brake pad consumption and price competition. Exploring adhesion theory showed that several models explain adhesion from different perspectives, chemical and/or physical adhesion has to be improved between phenolic resins and Twaron pulp.
Contact angle measurements and tensile or flexural strength are suitable methods to identify and quantify adhesion properties between Twaron pulp and phenolic resins. Shear strength and compressibility are suitable to identify the effect of adhesion improvement in relation to the application of brake pads.
A benchmark study was executed to show the performance of Twaron pulp in friction formulations compared to competitive materials, distinguished between short cut (not fibrillated) and pulp (fibrillated) types. Test samples were measured on filler retention values and flexural strength; formulations were prepared with variation in fibre types, concentrations, and phenolic resin types. Results indicated no competitive advantages for Twaron pulp, conclusions from results were difficult to draw because of high standard deviations. The effect of fibre concentration could be identified in resin type 0321 SP08, which also showed an overall higher result in flexural strength.
This paper developed and presented a model of functional benefits that can be achieved by adhesion improvement, based on interviews with experts from brake pad manufacturers and literature. Benefits can be distinguished between increase of product performance and manufacturing improvements. Product performance improves due to increased shear strength, compressibility, less fading, and reduction of phenolic resin content among others. Improved stability and homogeneity of the formulation is one the benefits during production.
Based on the results achieved in this research the conclusion can be drawn that the potential benefits and market needs are significant, Teijin Aramid should continue developing a pulp product with improved adhesion properties. However, further research and proof of concepts should lead Teijin to the decision if a pulp product with increased adhesion properties is profitable in the automotive brake pad industry.
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Index
Management summary ... 3 List of abbreviations ... 6 1. Introduction ... 7 1.1 Company ... 7 1.2 Products ... 8 2. Research design ... 9 2.1 Project background ... 9 2.2 Adhesion improvement ... 102.3 Research objective and deliverables ... 10
2.4 Research questions ... 11 2.5 Research framework ... 11 2.6 New products ... 12 2.7 Research model ... 13 2.8 Methodology ... 14 2.8.1 Data gathering ... 14 3. Theoretical background ... 16 3.1 Brake pads ... 16
3.1.1 What is a brake pad? ... 16
3.1.2 Friction material ... 17
3.1.3 Aramid pulp in brake pads ... 18
3.1.4 Phenolic resins in brake pads ... 18
3.2 Adhesion ... 19
3.2.1 Mechanical interlocking theory ... 19
3.2.2 Surface energy theory ... 20
3.2.3 Electrostatic theory ... 20 3.2.4 Diffusion theory ... 21 3.2.5 Chemical bonding ... 21 3.2.6 Physical interactions ... 22 3.2.7 Resumé ... 22 3.3 Quantification of adhesion ... 23 3.3.1 Quantification methods ... 23 3.3.2 Resumé ... 25
4. Current market position of Twaron pulp ... 26
4.1 Market overview ... 26
4.1.1 PEST Analysis ... 26
4.1.2 SWOT Analysis ... 28
4.2 Benchmarking ... 30
4.2.1 Short cut types ... 32
4.2.2 Pulp types ... 34
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5. Customer value ... 38
5.1 The buyer’s perspective ... 38
5.2 Functional benefits ... 39
5.3 Resumé ... 41
6. Technology ... 42
6.1 Clarify the problem ... 42
6.2 Technology Identification ... 42
6.2.1 Scientific literature ... 43
6.2.2 Intellectual property ... 45
6.3 Resumé ... 46
7. Conclusion & Discussion ... 47
8. Recommendations ... 49
9. Literature ... 51
Appendix I – Production process Twaron ... 54
Appendix II – Semi-structured interview brake pad manufacturer ... 55
Appendix III – SOP preparation of friction formulation ... 58
Appendix IV – SOP preparation and curing friction material ... 61
Appendix V – SOP Filler retention value ... 63
Appendix VI – Test specifications flexural strength ... 66
Appendix VII – Interview summaries Federal Mogul & TMD Friction ... 67
Appendix VIII – Product data sheets phenolic resins ... 75
Appendix IX – Benchmark experimental results ... 77
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List of abbreviations
AM after market
ECP epoxy chloro propane reaction
FTIR fourier transform infrared spectroscopy ILSS inter-laminar shear strength
NAO non asbestos organic pads (brake pads without asbestos)
NVH noise, vibration and harshness (product characteristic brake pad) OEM original equipment manufacturing
OES original equipment service PAN poly acrylo nitrile (pulp product) PEST political, economical, social, technical PDS product data sheet
PPD raw material aramid (monomer), paraphenylene diamine PPTA chemical name aramid, poly(p-phenylene terephthalamide) QHSE quality, health, safety, environment
QRP research department pulp & shaping QMF ressort friction and sealing
R&D research and development
RFL resorcinol fluoride latex treatment SEM scanning electron microscope SOP standard operating procedure
SWOT strengths, weaknesses, opportunities, threats
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1. Introduction
This chapter is dedicated to give a brief introduction about the area of interest in this research. First an introduction about the company is presented, followed by a focus on the department where this research is conducted and a glance into the product portfolio of Teijin Aramid.
1.1
Company
Teijin Aramid is part of the Japanese Teijin Group, a multinational consisting of 150 companies, having more than 17,500 employees worldwide and is listed on the stock exchanges of Tokyo and Osaka. It’s total sales volumes are approximately 7.5 billion (USD) per year. The Teijin Group is a global technology driven company, operating in eight main fields:
• Aramid fibres
• Carbon fibres & composites • Fibre products marketing • Films
• IT businesses
• Medical & pharmaceutical • Plastics
• Polyester fibres
The mission of Teijin Aramid is to be the worldwide market leader in the high-performance fibre industry. Teijin Aramid manufactures high-high-performance para-aramid fibres at its production facilities in Arnhem, Delfzijl and Emmen. The monomer and polymer are produced in Delfzijl, after transport to Emmen filament yarn is spun from the polymer solution. Aramid pulp is produced both in Emmen and Arnhem. Besides a production site, the headquarters of Teijin Aramid is also located in Arnhem. The sales and marketing activities within Teijin Aramid are organized according to nine specific fields of application, called ressorts:
• Ballistics
• Composites & Intermediates • Friction, Sealing & Paper • Heat & Cut Protection
• Mechanical Rubber Goods & Tires • Optical Fibre Cables
• Oil & Gas • Recycling
This research is fulfilled at the Research Institute of Teijin Aramid in Arnhem, which is divided in nine different groups, each with their own specific field of expertise. More specifically, this thesis is fulfilled at the department Pulp & Shaping (QRP), commissioned by the ressort Friction, Sealing, and Paper (QMF).
The activities of QRP are in the field of Twaron pulp, where research efforts are put into the processing of fibres in pulp, the field of jet-spun pulp, and in the field of shaping Twaron as a tape, paper, or shield for example. The above mentioned research activities can be divided in plant and sales support, technical developments, and research projects. The main customers or clients for QRP are the production facilities in Emmen and Arnhem, and ressort QMF.
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1.2
Products
Aramid fibres are aromatic polyamides developed first in the 1960s, and have outstanding characteristics when it comes to strength, weight, thermal stability and chemical resistance. Teijin Aramid distributes its products under the brand names Twaron, Technora, Sulfron and Teijinconex. Depending on brand name, the aramid fibres are available in five different forms; filament yarn, staple fibre, shortcut fibre, powder and pulp (Figure 1). From this point, only Twaron will be considered since this is the product of interest in this thesis.
Figure 1 - Products
Twaron is a para-aramid with the chemical name PPTA (poly(p-phenylene terephthalamide)), produced from the monomers TDC (terephthaloyl dichloride) and PPD (paraphenylene diamine) and is five times stronger than steel (Figure 2). The main product is filament yarn, often used as reinforcing material in applications such as ballistic protection products, composites, or ropes and cables.
Figure 2 - Chemical structure Twaron
The polymer powder material is yielded during a polymerization process, where after the powder is dissolved in sulphuric acid and spun into filament yarn (a schematic representation of the production process is included in Appendix I). During the spinning process the molecules are highly oriented with molecule chains running parallel to the axis of the yarn, contributing to the extraordinary properties of Twaron. From the aramid yarn, products as staple fibre, pulp and shortcut fibre are produced, each with their own specific characteristics. The unique characteristic of aramid pulp is that it has a high specific surface area in relation to the weight of the material, up to twelve m2/gram. Twaron pulp products are produced for the largest part from Twaron filament yarn and have undergone several modifications. First the Twaron filament yarn is cut into short fibres between five and twenty mm. Afterwards the short fibres are suspended in water and fibrillated in a refiner, where fibres are crushed. The purpose of fibrillation is the increase of the specific area of the fibres. From here the pulp is either packed straight away, to be marked as wet pulp, or dehydrated and sold as dry pulp.
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2. Research design
This chapter describes the foundation for this research, starting with the problem background. Sequentially, the research goal, conceptual model, research questions, research model, methodology and resources for data gathering are described.
2.1
Project background
This research will focus on improving adhesion properties of Twaron pulp used in brake pads for the automotive sector to increase customer value.
In recent years several companies from emerging economies started producing aramid pulp. This results in growing competition; forecasts suggest that sales prices will be under pressure in the (near) future. Within Teijin, the idea exists that the company should avoid competition on price strategies by offering specialized products and adding value towards customers. Another reason for this research subject is that expansion of sales volumes and market share are part of the business strategy of Teijin Aramid in the coming years.
The above mentioned reasons, together with the need to be more innovative within QMF resulted in a ‘new technology program’ that must lead to new specialized products. One of the ideas derived from this program is the focus on the automotive market where demand raises for higher performance, comfort, and more environmentally friendly brake products (Research and markets, 24-8-2011). In addition, stricter regulations force brake pad manufacturers reducing the environmental impact caused by brake pad components. To develop products that lead to increased customer value, there has to be explored what customer value means in the friction materials industry. Therefore, a conceptual model was developed including factors influencing customer value which is presented in Figure 3.
Figure 3 - Conceptual model
Customer value in the friction materials industry is influenced by functional benefits in the brake pad application. Aramid pulp benefits to strength of brake pads, reduces its noise level and reduces wear rate (Hahn, 2000). These are important product characteristics, adding value to the customer.
The degree of technical support as a service influences customer value. Technical support includes product (aramid) knowledge, test facilities, product recommendations and development support. Supply reliability influences customer value including product, quantity, and time commitments.
Aramid pulp adds value during production of brake pads, preventing a friction material falling apart. This influences both customer value and brake pad characteristics.
10 The product characteristics of aramid pulp are influenced by the quality of raw materials, performance of the production process, and (new) product development. The latter also includes product improvement. Price influences raw materials, production process, and development of aramid pulp, and therefore indirectly influences aramid’s pulp product characteristics. Price influences customer value as well, since a brake pad manufacturer shall consider the balance between price and product benefits.
Summarizing, this conceptual model shows that customer value is not only influenced by product characteristics of Twaron pulp. Technical support, price, and reliability also influence customer value and can gain a competitive advantage for Teijin Aramid. Now a clear understanding of customer value in the friction materials market is provided, the research elaborates further on its research topic.
2.2
Adhesion improvement
This paragraph elaborates further on the conceptual model, and provides a research idea to increase customer value of Twaron pulp. This research will focus on product development of Twaron pulp, increasing its product characteristics. One of the research ideas that can benefit to these goals is adhesion improvement of Twaron pulp. In several discussions of Teijin with brake pad manufacturers the ‘need’ of better adhesion properties of Twaron pulp was mentioned. This idea needs further investigation both in a technical and marketing perspective. The idea is that improvement of adhesion properties can lead to a reduction of phenolic resins (a harmful substitute of brake pads) and better product characteristics.
A first exploration in scientific literature shows that adhesion of aramid towards phenolic resins is not optimal, and has opportunities for improvement. The research of Guo et al. (2009) investigated the adhesion between an aramid fabric and phenolic resin. As can be seen in the left (A) SEM (scanning electron microscope) photograph (Figure 4) there is little affinity between aramid and phenolic resin. The aramid yarn is only covered with small particles of phenolic resin. The right photograph B shows adhesion improved aramid yarn, with better affinity to phenolic resin. The yarn surface is almost completely covered with resin.
Figure 4 - SEM aramid/phenolic composite
2.3
Research objective and deliverables
The goal of this project is to provide clear insights towards the possibilities of adhesion improvement of Twaron pulp. The final result should include a report with both technical and market opportunities outlined. Also the possibilities for cooperation with knowledge institutes and other companies (resin suppliers) will be considered in this research project. Below the deliverables for this research are presented.
• Overview of current position of aramid pulp in the brake pad market.
• Prepare an overview of relevant external literature related to adhesion of pulp in (phenolic) resins.
11 • Present a selection of most promising options regarding the improvement of adhesion of pulp in (phenolic) resins (and/or the reduction of the amount of (phenolic) resin in brake pads) and indicate:
o Advantages / disadvantages. o Possible alternatives.
o Required expertise, equipment and resources.
o What knowledge centres, universities, etc will have relevant knowledge in this area and possibly would be interesting partners for joint- or co-developments.
• Present a suitable way to quantify adhesion properties of Twaron pulp. • Overview of customer needs.
2.4
Research questions
Now the conceptual model is created and the deliverables are clear, the research questions can be defined.
Main question:
What are the possibilities for adhesion improvement of aramid pulp, and shall this result in increased customer value and a competitive advantage for Teijin Aramid in the friction
materials market? Sub questions:
1. How can the adhesion of aramid pulp (towards phenolic resins) be improved? 2. What is the current position of aramid pulp compared to competitive materials in
the brake pad market?
3. What will be the value for the customer if adhesion characteristics of Twaron pulp are improved?
4. What are the most promising technologies that can be used to improve adhesion properties of aramid pulp?
2.5
Research framework
Every research should include clear research boundaries wherein the researcher operates (Yin, 2003). The research will investigate the effect of adhesion improvement of Twaron pulp on the customer value for brake pad manufacturers. Therefore, a revised conceptual model is presented to define the framework of this research (Figure 5). The revised conceptual model elaborates on the conceptual model from Figure 3, zooming in on adhesion improvement of aramid pulp. Factors mentioned in the conceptual model but removed in the revised model, still influence customer value but are not taken into account in this research.
As can be seen in Figure 5, the factors brake pad characteristics and production process are covered in this research assuming they are positively influenced by adhesion improvement. Adhesion improvement possibly contributes to improved strength, reduced noise level and/or decreased wear rate. Adhesion improvement of aramid pulp is influenced by technology, current product properties, and development. The current product properties form the starting point for adhesion improvement, where a technology has to be developed to achieve this goal. Adhesion improvement should result in improved product characteristics, which are also influenced by the environment. As can be seen in Figure 5, a third product characteristic (adhesion) is added next to the fibre length and filler retention value.
12 Chapter three will start exploring the current product characteristics. In this chapter also a theoretical foundation regarding adhesion will be drafted.
An environmental analysis is provided in chapter four, including the current market position of Twaron pulp and market trends in the friction industry. Legislation will not be studied in its extent and only will be mentioned in general when it affects market trends. Chapter five explores the opportunities and benefits of adhesion improvement in the application of the customer (brake pads) and its production process. This should have a positive effect on customer value. Besides that, chapter five explores the benefits of adhesion improvement in Twaron pulp.
Technological possibilities for adhesion improvement will be explored in chapter six of this research. The variable “price” is not covered in this research, as show in the revised conceptual model.
Figure 5 – Revised conceptual model
2.6
New products
According to Crawford & DiBenedetto (2008) a new product concept consists of a need, a form and a technology (Figure 6). Ulrich and Eppinger (2008) state that a new product concept is an approximate description of its working principles, technology and the form of the product that is going to be developed. The form is the physical thing or product created. The technology is the source by which the form is attained. These principles must satisfy a need from the customer, only then will the product be successful. The three principles can be combined in the following way: ‘technology permits us to develop a form that provides the benefit’. If one of the three is missing, there cannot be successful product innovation (Crawford & Dibenedetto, 2008).
need and the technology have to be identifie model.
2.7
Research model
As already mentioned, includingthe final stages of product development is risky. According to
‘user needs’ and ‘customer and market understanding’ are of central importance in predicting the success or failure of a
needs of customers is believed to result
and Eppinger (2008) state that interaction with customers in the target market will help the development team build
point of view. This information is always useful, even if it does not result in the identification of every need the new product will address.
However, this project focuses on technology push strategy. To int
technical idea of adhesion improvement, the inter (1992) is adapted (Figure 7)
communication paths, both intra
in-house functions and linking the firm to the broader scientific and technological community and to the marketplac
that it emphasizes on a continuous interaction between technological knowledge and needs from the market, with
this results in putting techn
customer needs. Vice versa, needs are put in
possibilities. Although the interactive model is taken over by newer generations of product development models
project.
need and the technology have to be identified yet, which are covered in the conceptual
Figure 6 - New product concept
Research model
including the benefit for the customer, or the customer need in the final stages of product development is risky. According to Burgelman et al. (2009) ‘user needs’ and ‘customer and market understanding’ are of central importance in or failure of a new product. Understanding of the market and the needs of customers is believed to result in products with high value. In addition, Ulrich and Eppinger (2008) state that interaction with customers in the target market will help the development team build a personal understanding of the user’s environment and point of view. This information is always useful, even if it does not result in the identification of every need the new product will address.
focuses on a rather technical product idea, corresponding
technology push strategy. To integrate the customer needs and benefits with the technical idea of adhesion improvement, the interactive coupling model from Rothwell
). This innovation process can be seen as a “
communication paths, both intra-organisational and extra-organisational, linking together house functions and linking the firm to the broader scientific and technological community and to the marketplace” (Rothwell, 1992). The strong aspect
that it emphasizes on a continuous interaction between technological knowledge and , with the firm placed in a central perspective. For this
in putting technical ideas constantly in the perspective of the market and , needs are put in the opposite perspective of technological Although the interactive model is taken over by newer generations of product development models, it fits into the perspectives and goals of
13 d yet, which are covered in the conceptual
14 Figure 7 – Coupling model Rothwell
2.8
Methodology
In this paragraph the methodology of the research is outlined, comprising various tools and techniques to investigate the situation of interest. The methodology chosen for this research is a case study research, which is an empirical inquiry that investigates a contemporary phenomenon within its real life context, especially when the boundaries between the phenomenon and context are not clearly evident (Yin, 2003). A case study research is helpful when, how, or why questions are placed, when the investigator has little control over events, and when the focus is on a contemporary phenomenon within some real life context. According to Yin (2003), the singular case study is particular useful when a unique event is being studied, which is the case in this project.
According to Yin (2003) the need in case studies to use multiple sources of evidence exceeds that in every other research strategy. Strength of data collection in case studies is the opportunity to use many different resources of evidence. Triangulation is used in this research to improve the quality and reliability of the collected data.
2.8.1 Data gathering
During the research different sources of information were consulted, as described in this section.
Literature
Literature was gathered from internal and external sources. The source for internal literature was ZyImage, the internal publication database for the company. External literature was gathered from the internet, patents, scientific articles and books. Scientific articles were gathered from different scientific databases such as Science direct, Wiley online library, Emerald, and Business source premier. Patents were obtained from European, Asian and American databases.
Interviews
Interviews can be of a structured, unstructured, or an open nature (Yin, 2003). Most interviews were of a semi-structured nature, and some were open because of the qualitative character of this research. Below an overview is presented with interviews performed.
• Sales department Composites & Intermediates (QMC) o Technical account manager
• Sales department Friction, Sealing & Paper (QMF) o Senior technical account manager
• Research Institute (QRI), department Pulp & Shaping (QRP) o Section head Pulp & Shaping
• Research Institute (QRI), department QRE
R&D Manufacturing Marketing Market place Idea
generation
State of the art science and technology
Needs of society and the market place
Technology push
15 o Materials scientist
• Research Institute (QRI), department Finishes (QRF) o Senior researcher
• Momentive Specialty Chemicals – Iserlohn, Germany o Business Manager Industrial Resins
o Technical Manager, Application Development and Technical Service • Federal Mogul (Brake pad manufacturer) – Bad Camberg, Germany
o Director basic research and portfolio
• TMD (Brake pad manufacturer) – Leverkusen, Germany
o Group director raw material portfolio management / six sigma master black belt
o Specialist raw material portfolio management Course
As part of the project the researcher visited a course regarding adhesion and adhesion improvement. This seminar was instructed by Dr. Kash L. Mittal, a specialist in the field of adhesion science. Knowledge and data obtained from this seminar are used in the fulfilment of this research.
Experiments
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3. Theoretical background
This chapter handles two main subjects to provide a clear understanding of the fundamental topics in this research. According to Crawford & Dibenedetto (2008) it is essential to move into the perspective of the customer. Therefore it is essential to get an understanding about brake pads for automobiles. Also a literature search about adhesion theory is presented, including its quantification.
3.1
Brake pads
3.1.1 What is a brake pad?Brake pads are used to stop all kinds of moving objects such as passenger vehicles, motorcycles, bicycles, but also windmills, cranes and elevators. In other words, the purpose of a brake pad is to convert the kinetic energy of a vehicle or object in thermal energy by means of friction. It is expected to do so in a predictable manner under a wide range of temperatures, speeds and other environmental conditions (Sloan et al., 2006). The brake pad is part of a braking system, in passenger vehicles these systems can be divided in drum brakes and disc brakes. In a disc brake system, the brake pad is forced by a calliper to a rotor when the driver forces the brake pedal. The rotor is attached to the axle of the vehicle; the brake pad converts the kinetic energy of the rotor into thermal energy. A drum brake system consists of brake shoes instead of brake pads which are mounted into a brake drum. When the driver pushes the brake pedal, a cylinder forces the brake shoes on the brake drum, which is connected to the axle of the vehicle. The brake shoes convert the kinetic energy of the axle into thermal energy; Figure 8 shows a schematic overview of the different brake systems.
The braking power of disc brakes is higher than drum brakes; therefore drum brakes are less used in passenger vehicles. Drum brakes are used in the lower price segments of passenger vehicles and only on the rear axles of the vehicle.
Figure 8 - Brake systems
Focusing more on the brake pad, the brake pad consists of a backing plate, a friction surface and sometimes a shim. The shim is a thin layer stuck on the back side of the backing plate to reduce noise and vibrations during braking. The backing plate is made of metal, and the friction surface is glued on it. The main component of the brake pad is the friction material including a composite containing several ingredients determining the performance of the brake pad. Friction materials can be classified in several categories, each with their own characteristics and applications (Chan & Stachowiak, 2004).
• Metallic • Semi-Metallic
• Non-asbestos Organic • Ceramic
17 fibres, rubber and graphite. The term ‘non-asbestos’ refers to the fact that since the early 1990s asbestos was replaced as ingredient in brake pads because public awareness raised about the environmental and hazardous risks of the use of this material. The NAO pad is softer compared to the others, resulting in less wear of the rotor disc and improved comfort for the driver and passengers of the vehicle. A disadvantage is the increased wear of the brake pad itself.
Although Chan & Stachiowak (2004) mention only three categories, a fourth one can be added with the ceramic brake pads. This type of brake pad is designed for high performance braking, and is mainly used in the high segment sports cars and for motorsports.
Figure 9 - Brake pad 3.1.2 Friction material
Now we know what a brake pad is and what different types of brake pads are available in the automotive market, we can focus more in detail on the friction material itself. According to Sloan et al. (2006) modern friction material formulations are proprietary mixtures of 10-20 different ingredients. These ingredients can be divided in four main components, which are (Sloan et al. 2006; Eriksson, Bergman & Jacobson 2002; Chan & Stachowiak 2004):
• Reinforcing fibres • Binders
• Frictional additives • Fillers
Chan & Stachowiak (2004) mention the above described sub-components have different functions in the brake pad and some ingredients can be placed in multiple classifications. Reinforcing fibres are providing mechanical strength to the friction material during high temperatures and pressures. Friction materials typically use a mixture of different types of reinforcing fibres with complementing properties. From this perspective, it is reasonable to expect that friction material wear will increase with a decreasing amount of reinforcing fibres (Chan & Stachowiak, 2004; Sloan et al., 2006). Examples of materials used as reinforcing fibres are glass fibres, metallic fibres, aramid pulp, PAN pulp, potassium titanate (ceramic), and ceramic fibres.
The purpose of a binder is to maintain the brake pads’ structural integrity under mechanical and thermal stresses (Chan & Stachowiak, 2004) and are ‘holding’ all different ingredients of a brake pad together (Sloan et al., 2006). It has to hold the components of a brake pad together to prevent its constituents from crumbling apart. Phenolic resins are by far the most used binders in friction formulations because of their relatively high temperature resistance and low cost price. A major disadvantage of phenolic resins is its brittleness, which is often improved by upgrading the resin with silicone or epoxy modifications (Chan & Stachiowak, 2004). Other types of resins are cyanate ester resins and polyimide resins, but less used mainly because of their cost price.
18 coefficient of friction and disc wear. The purpose of the latter is to give a better defined rubbing surface by removing iron oxides and other undesired surface films from the disc (Eriksson et al., 2002). Some frictional additives can be regarded as fillers by several brake pad manufacturers if they are added in large quantities (Chan & Stachiowak, 2004).
The fillers are present in a brake pad to improve its manufacturability as well to reduce the overall cost of the brake pad (Eriksson et al., 2002). There are two main classes of fillers, which are organic and inorganic. Although fillers are not as critical as other components of a brake pad, they are modifying certain characteristics of a brake pad. The selection of fillers in a friction formulation depends on the other components, as well as the type of friction material. Metallic brake pads should contain fillers such as cashew dust and mica to suppress the noise, instead of barium sulphate to increase the heat stability. Semi-metallic brake pads on the other hand, should include fillers such as molybdenum trioxide, to compensate the variances in thermal expansion from the combination of metallic and organic compounds. Other fillers often used are calcium carbonate (heat stability), Alkali metal titanates (stability of friction coefficient) and rubber dust (suppresses brake noise) (Chan & Stachiowak, 2004).
3.1.3 Aramid pulp in brake pads
Most literature describes aramid pulp as a reinforcing fibre in brake pads that preserves the structural integrity. Besides that aramid pulp is also responsible for performance characteristics such as reduction of the wear rate. According to Sloan et al. (2006) aramid pulp is routinely used in friction formulations for the following reasons:
• Processing aid • Thermal stability • Imparts strength • Low specific weight
• Reduced noise and judder
Furthermore, Chan & Stachowiak (2004) mention that aramid pulp causes superior anti-fade and wear resistance properties in brake pads. Aramid pulp has also been utilized in maintaining the uniformity of the brake pad material mixture during the processing of a moulded brake pad. Aramid pulp is responsible for retaining the homogeneity in a friction formulation during processing before the binder (resin) is cured and keeps the friction formulation together.
3.1.4 Phenolic resins in brake pads
Phenolic resins are used as a binder in brake pads and are relatively cheap and easy to produce. The purpose of a binder is to maintain the brake pads’ structural integrity under mechanical and thermal stresses (Chan & Stachowiak, 2004). It has to hold the components of a brake pad together and to prevent its constituents from crumbling apart. Phenolic resins can be used in its pure form, but mostly they are modified to improve properties such as heat and impact resistance.
From literature it becomes clear that phenolic resins show several disadvantages for usage in friction materials. Phenolic resins are composed from phenol and formaldehyde, which are both highly toxic substances. Because of their relatively low heat resistance phenolic resins decompose above temperatures of 450 °C, which occurs in high-energy braking applications. According to the occupational health and safety administration of the US department of labour, formaldehyde is classified as a human carcinogen that can cause nasal and lung cancer, while phenol causes liver damage and blindness, among other effects (Chan & Stachowiak, 2004).
Another significant disadvantage of phenolic resins is that they are brittle and have a very low impact resistance. The research from Jang et al. (2001) shows that the larger the quantity of phenolic resin used the larger the friction coefficient fluctuations will be, causing problems for brake pad manufacturers ensuring product quality.
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3.2
Adhesion
Adhesion is any attraction process between dissimilar molecular species that can potentially bring them in close contact; it is the phenomenon of attraction between different types of materials and surfaces (Packham, 2004). According to Mahy et al. (1994) interfacial adhesion can be dominated by chemical bonding, by physical interactions, by mechanical keying, by diffusion of components of the pre-treatment into the fibre, or by an intricate combination of these. From this point of view we can conclude there are various theories or mechanisms that describe adhesion each from a different perspective. There is no single theory or mechanism that sustains to give proper answers on all practical situations of adhesion forces; various theories or mechanisms are used in adhesion science, each trying to explain and justify specific situations of the phenomenon of adhesion (Mittal, 2011).
In addition to the fact that an appropriate theory has to be determined describing the adhesion forces of a practical situation, forces between dissimilar molecules are influenced by internal stresses from the bulk material (e.g. shrinkage after curing) (Mittal, 2011). Factors affecting adhesion strength are intrinsic stresses and stress concentrations, mechanical responses of bulk in various phases, geometrical considerations, and visco-elastic behaviour. A practical example is shrinkage of a resin during curing; internal stress can rise and influence interfacial behaviour.
A metaphor helping to understand adhesion from a practical perspective, derived from K. Mittal (Mittal, 2011) is presented below:
“Quality and quantity of intimacy”
The rationale behind this metaphor is that both quality of the bond and the quantity or ratio of the surfaces of materials bonding together have to be sufficient to achieve high bond strength.
Considering adhesion properties of aramid fibres, their surfaces are chemically inert, deriving from the high crystallinity of the aramid fibre surface layer and the lack of polar functional groups in the molecule chain (Liu et al., 2010). Watanabe et al. (2000) argue in their research that the surface of aramid fibres is relatively inactive, resulting in insufficient adhesion properties to rubbers and resins. Therefore surface modification of aramid is needed to improve compatibility with other components (Mahy et al., 1998). This paragraph will continue with a description of adhesion theories and how these are applicable on adhesion of Twaron pulp. The focus will be on adhesion of Twaron pulp in brake pads, and more specifically towards phenolic resins.
3.2.1 Mechanical interlocking theory
This theory describes adhesion as a mechanical process that interlocks materials because of their porosity, voids and holes present on their surfaces (Figure 10). The following expectations should be observable when this theory is valid. First, if surface irregularity and porosity becomes higher then joint strength will increase. Second, the greater the compatibility of the size of the adhesive and the adherent, the higher the joint strength will be.
Figure 10 - Mechanical interlocking model
If this theory applies, adhesion strength can be explained completely by the mechanical forces due to interlocking of the different materials (Mittal, 2011).
20 later. This theory does not apply to aramid yarn, due to its smooth surface (Guo et al., 2009).
Figure 11 - aramid pulp structure 3.2.2 Surface energy theory
Good wetting is a prerequisite to achieve good adhesion between a fibre reinforcement and a matrix (Zhong et al., 2009). Wetting is the ability of a liquid to maintain contact with a solid surface, and is influenced by the surface energy of materials.
The wettability of a liquid on a solid surface can be quantified by contact angle measurements (Figure 12). In a contact angle measurement a single droplet of a liquid is put on a solid surface. The angle where the surface of the liquid touches the solid surface is measured. As can be seen in Figure 12, if the droplet touches a little amount of solid surface the contact angle is larger than 90° resulting in poor wetting behaviour. If the droplet touches a large amount of solid surface, good wetting behaviour occurs and the contact angle is smaller than 90° (Mittal, 2011).
The contact angle can be used to calculate the surface energy or surface tension of a material, according to Young’s equation (Zhong et al., 2009). The surface energy of a material can be considered as a degree of capability to interact with other materials.
Figure 12 - Surface energy
The wettability of aramid and phenolic resin is an important indicator for determining adhesion, also with respect to the production process of brake pads. Phenolic resin is a solid component in a friction formulation, and becomes in a liquid phase when mould temperature rises during processing of the brake pad. When temperature further increases the resin starts curing and becomes solid again. During the liquid phase time of the phenolic resin it has to interact with all substitutes in the formulation, including aramid pulp. If wettability of phenolic resin on the aramid pulp increases, larger proportions of aramid pulp surface will interact with resin. As a result, adhesion between aramid pulp and phenolic resin will increase.
3.2.3 Electrostatic theory
21 Figure 13 – Electrostatic model
3.2.4 Diffusion theory
This theory of adhesion describes the phenomenon of diffusion of molecules between the surfaces of materials; it describes adhesion from the viewpoint that molecules do penetrate the surface of the other material. In other words they are soluble in each other (Figure 14) (Mittal, 2011). In this way an exchangeable layer of compatibility between the different materials is created. The strength of a joint can be described as in equation one:
ܨ = ݂ܳܰ
Equation 1 – Diffusion adhesion
Where f is the strength of a single intra-molecular bond, Q is the number of molecular chains crossing the boundary, and N is the depth of penetration in units of atomic groupings (CH2). The theory may be valid primarily in the bonding of thermoplastic materials; it cannot explain adhesion between polymers and metals, metals and metals, metals and glass etc. Another limitation of this theory is that it cannot explain adhesion between incompatible polymers. There is also no applicability of this theory to describe adhesion forces of aramid pulp, because aramid pulp is insoluble in almost all materials and/or solvents.
Figure 14 – Diffusion model 3.2.5 Chemical bonding
Chemical bonding occurs when molecules on the surface of the substrate and adherent react together to form a true chemical bond (Chugtai et al.,2008). A chemical bond is the physical phenomenon of chemical species being held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons. Chemical bonding is the strongest interaction force among molecules or atoms (Liu et al, 2010; Butt et al., 2008). The principle of this theory is that atoms or molecules form a covalent bond or ionic bond result in adhesion between a substrate and adherent. Covalent bonds arise when electron pairs of atoms are shared, a neutral collection of atoms held together by covalent bonds are molecules (e.g. water; H2O or methanol; CH3OH). Ionic bonds are formed when valence electrons are migrated between atoms resulting in an electrostatic attraction (e.g. NaCl) (McMurry & Simanek, 2007).
Mahy et al. (1998) conclude that a significant amount of research emphasizes the significance of covalent bonding as a necessary condition for improving interfacial adhesion of aramid fibre. On the other hand, evidence is shown that neither covalent bonding nor diffusion phenomena are present in aramid-epoxy systems.
attracted to each other by hydrogen bonds of the aramid structure.
Figure
Considering the molecule structure of phenolic resins ( groups are approachable for covalent a
used as ingredients in brake pad formulations, they are distinguished on their formaldehyde phenol ratio. In novolak resins this ratio is smaller than one, the ratio in resole resins is larger than one.
There is no natural attraction between ph
because the bond strength between the amide and carbonyl groups is higher than the bond strength that can arise with the hydroxyl groups of the phenolic resin (McMurry & Simanek, 2007).
Figure 3.2.6 Physical interactions
Physical interactions or bonds can form through Van der Waals forces, London dispersion forces, and hydrogen bonds. Physical bonds are weaker compare
bonds, but are sufficient to make strong joints
Hydrogen bonds are electromagnetic interactions between polar molecules and electronegative atoms. Polymer materials are often strengthened by hydrogen bonds, also in aramid fibres. The hydrogen bonds formed in the amide and carbonyl groups are relatively strong and hold the different polymer chains together (
Van der Waals forces are rather likely to occur at the aram
bonds are much stronger in case of aramid. Considering London dispersion forces, explanation is identical to that of
3.2.7 Resumé
This paragraph described adhesion theories and their applicability to Twaron pu
described mechanical adhesion is accepted and assessed in terms of the filler retention value for Twaron pulp. Adhesion of Twaron pulp with phenolic resins has to be improved in terms of chemical adhesion and physical adsorption. Also adhesion from
perspective has to be considered to achieve improved compatibility of Twaron pulp with phenolic resins.
by hydrogen bonds. Ionic bonds can also arise on amide groups
Figure 15 - Aramid polymer structure
Considering the molecule structure of phenolic resins (Figure 16), the functional hydroxyl groups are approachable for covalent and ionic bonds. Novolak and resole resins both are used as ingredients in brake pad formulations, they are distinguished on their formaldehyde phenol ratio. In novolak resins this ratio is smaller than one, the ratio in resole resins is larger than one.
here is no natural attraction between phenolic resins and Twaron aramid. This is the bond strength between the amide and carbonyl groups is higher than the arise with the hydroxyl groups of the phenolic resin (McMurry &
Figure 16 - Molecule structure phenolic resin Physical interactions
Physical interactions or bonds can form through Van der Waals forces, London dispersion forces, and hydrogen bonds. Physical bonds are weaker compared to covalent or ionic bonds, but are sufficient to make strong joints (Comyn, 1997).
Hydrogen bonds are electromagnetic interactions between polar molecules and electronegative atoms. Polymer materials are often strengthened by hydrogen bonds, amid fibres. The hydrogen bonds formed in the amide and carbonyl groups are relatively strong and hold the different polymer chains together (Figure
Van der Waals forces are rather likely to occur at the aramid surface since hydrogen bonds are much stronger in case of aramid. Considering London dispersion forces,
that of van der Waals forces.
This paragraph described adhesion theories and their applicability to Twaron pu
described mechanical adhesion is accepted and assessed in terms of the filler retention . Adhesion of Twaron pulp with phenolic resins has to be improved in terms of chemical adhesion and physical adsorption. Also adhesion from
perspective has to be considered to achieve improved compatibility of Twaron pulp with
22 . Ionic bonds can also arise on amide groups
), the functional hydroxyl nd ionic bonds. Novolak and resole resins both are used as ingredients in brake pad formulations, they are distinguished on their formaldehyde phenol ratio. In novolak resins this ratio is smaller than one, the ratio in enolic resins and Twaron aramid. This is the bond strength between the amide and carbonyl groups is higher than the arise with the hydroxyl groups of the phenolic resin (McMurry &
Physical interactions or bonds can form through Van der Waals forces, London dispersion d to covalent or ionic Hydrogen bonds are electromagnetic interactions between polar molecules and electronegative atoms. Polymer materials are often strengthened by hydrogen bonds, amid fibres. The hydrogen bonds formed in the amide and carbonyl groups are
Figure 15).
id surface since hydrogen bonds are much stronger in case of aramid. Considering London dispersion forces, the
23
3.3
Quantification of adhesion
Adhesion cannot be quantified in terms of measurement; adhesion can only be calculated from theoretical models (Mittal, 2011). This statement refers to fundamental adhesion, corresponding to the energy required to break adhesive bonds at the weakest plane of a two phase system or the forces between atoms at the interface (Mittal et al., 1995; Packham, 2004; Pocius, 2002). Fundamental adhesion cannot be measured since there are always other factors affecting the adhesion and measurement system.
However, to determine adhesion forces it is necessary to quantify it in measurable terms. Therefore, the term practical adhesion is introduced, which is measurable or quantifiable. The measurement of practical adhesion includes fundamental adhesion together with other factors including stress of the bulk or substrate material, measurement errors, and environmental influences such as temperature or relative humidity (Figure 17).
Figure 17 - Practical adhesion
As described above, only practical adhesion can be measured and is influenced by many factors. Therefore, during adhesion measurements it is preferable to execute comparative studies; comparing a sample against a benchmark or blank sample. Besides that, to predict the adhesion in an application, adhesion measurements need to be measured in conditions as close as possible to the conditions of the specific application.
3.3.1 Quantification methods Pull-out tests
These approaches of adhesion testing measure the strength that is needed to pull a fibre out of a matrix. Various approaches are used such as the single fibre pull-out method were just a single filament of fibre is placed in a droplet of resin (Liu et al., 2010). Another variant is the bundle pull-out (Figure 18) where a fibre yarn is pulled out of a resin matrix (Yue & Padmanabhan, 1999).
Single fibre pull-out tests can be executed with Twaron pulp in theory, although high fluctuations in strength will be expected due to variations in fibre thickness and surface roughness. Adhesion improvement experiments for Twaron pulp can be executed on Twaron yarn in first instance. Sequentially, bundle pull-out tests can be performed to measure the effect of the surface improvement. A disadvantage of adhesion improvement on aramid yarn is its low surface area and smooth surface, the effect maybe rather small compared to adhesion improvement on Twaron pulp with high surface area.
24 Figure 18 - Bundle pull-out test
Contact angle test
Contact angle measurements can be used to determine the wettability of phenolic resins on Twaron pulp. As mentioned in the previous paragraph wettability is a suitable characteristic to indicate adhesion behaviour. Particularly for brake pads since phenolic resins have little time to interact with Twaron pulp before curing in the production process.
One condition for contact angle measurements is that measurements have to be performed on a smooth surface. Twaron pulp however, does not fit to this requirement. A possibility to satisfy this condition is to produce “paper” sheets from Twaron pulp, various equations calculating surface energies are available adjusting for surface roughness (Comyn, 1997). He et al. (2008) performed research on surface energy measurements of (meta) aramid fibres and pulp sheets. Results showed that surface energies of pulp sheets were slightly lower compared to fibre samples. This research indicates that contact angle measurements can successfully be executed with sheets prepared from Twaron pulp.
Filler retention value
The filler retention value is a proper method to measure mechanical adhesion properties of Twaron pulp in brake pad applications. This method is widely accepted and assessed in Twaron pulp applications. A standard operating procedure is included in appendix V. Mechanical testing
Testing mechanical properties of polymer materials is performed to predict the materials behaviour in its application. Therefore, the method of testing needs to be close to and translatable to the purpose of the material in the application it is going to be used in (Mittal, 2011). Below mechanical tests are selected which are in relation to the usage of friction formulations in brake pad applications, and can determine the effect of adhesion improvements of Twaron pulp.
Tensile strength tests are the most common tests performed on composite materials, in which the failure of a linear force is measured (Swallowe, 1999). Tensile strength measurements can be performed on Twaron pulp/phenolic resins combinations or complete friction formulations. The effect of improved adhesion should become visible in terms of strength. However, measuring tensile strength of friction formulations cannot determine the effect of adhesion improvement between Twaron pulp and phenolic resins purely since other factors can influence the strength of the matrix.
The flexural strength method measures the materials ability to bend before failure; during bending the material collects both tensile and compressive forces (Swallowe, 1999). Comparable to tensile strength measurements, the effect of adhesion improvement should become visible in terms of strength.
25 pads undergo during braking because the pad is squeezed to the brake disc under high forces. Brake pad manufacturers assess their formulations on compressive, shear, tensile, and flexural strength. Shear strength measures the force of a sliding failure on a material; brake pads undergo this type of force during braking since the braking disc rotates along the surface of the brake pad (Chan & Stachiowak, 2004).
3.3.2 Resumé
This chapter indicated methods to quantify adhesion of Twaron pulp to phenolic resins in terms of strength and wettability. Not one method can be designated as most appropriate, since each method obtains different advantages.
Contact angle measurements are most suitable to indicate whether the combination of Twaron pulp and phenolic resin will possibly result in good adhesion. However, research has to be performed on using Twaron pulp sheets in this method.
The effect of improved adhesion properties can be measured in terms of strength, which is also assessed in the application of brake pads itself and provides a first indication of functional benefits for the customer. Tensile and flexural strength methods are widely accepted to determine effects of adhesion improvement, while compressive and shear strength are interesting for the application of brake pads.
Pull-out methods can be used to determine improved adhesion in terms of strengths, although these methods presumably have to be executed with yarn. The pull-out tests are difficult to translate to the application of brake pads. Besides that, the effect of adhesion improvement is possibly more difficult to indicate on aramid yarn in comparison to pulp with respect to surface roughness and specific surface area.
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4. Current market position of Twaron pulp
This chapter includes the current market position of Twaron pulp compared to competitive materials in the brake pad industry. First, trends in the brake pad market will be identified according to a PEST analysis, followed by a SWOT analysis to indicate characteristics of the ressort QMF in the current brake pad market.
A benchmark study is performed to compare performance of Twaron pulp against competitive materials also used by brake pad manufacturers.
4.1
Market overview
This paragraph presents an overview of the market for brake pads in the automotive industry. As mentioned before in the research design, there are several applications for brake pads, however this thesis will focus on the application of brake pads in the automotive industry. This represents almost ¾ of the sale volumes in the total brake pad industry (Research and markets, 24-08-2011).
The market overview will be presented according to the PEST analysis (Figure 19). This method includes Political, Economical, Sociological, and Technological factors. Although the PEST analysis is especially designed for describing the macro environment, it will be used to describe the market also on a micro and meso level. Data presented in the PEST analysis is gathered from brake pad manufacturers during interviews, and from literature. Subsequently, the data from the PEST analysis will be used for a SWOT analysis to indicate the strengths, weaknesses, opportunities and threats for QMF in the automotive market. First some general observations with respect to market characteristics are mentioned:
• Non-cooperative market; there is no or minimum cooperation between suppliers and brake pad manufacturers. Also knowledge sharing were both suppliers and manufacturers could gain from is not present.
• Incremental innovations; there are no large developments in this market; innovations are mainly focused on comfort and performance improvement. Only regulations force manufacturers to innovate and modify their products. • Brake pad manufacturers greatly build on existing internal knowledge; the
performance and behaviour of brake pads can be seen as a ‘black box’, which became clear during interviews. The expertise of researchers is crucial in the development of friction formulations; experts can see a ‘fingerprint’ of the developer in a specific formulation. Although, industry is focusing on systems and statistics that further standardize development of formulations.
• Price focused; brake pad manufacturers are very price focused when it comes to purchase raw materials.
4.1.1 PEST Analysis Political
Environmental awareness has also its effects on the automotive brake pad market resulting in stricter regulations for the use of specific components in brake pads. This started in the mid 90’s with the removal of asbestos from brake pad, replaced by other materials as metallic, ceramic and aramid fibres (Tirebusiness.com, 12-8-2011). More recently this trend continued with the removal from Copper in brake pads, initiated in the U.S. since 40% of the copper content of the surface water in several areas can be related to dust from brake pads. The worldwide trend from brake pad manufacturers is going to complete copper free brake pads already, as the regulations prescribe a content of < 5.0 % from 2013 (Tirebusiness.com, 12-8-2011).
27 Figure 19 - PEST analysis
Economical
The automotive brake pad market is partly dependent on sales volumes of new vehicles, although brake pads are replaced approximately four to five times during the vehicle’s lifecycle. Brake pad manufacturers distinguish their market into three different segments: • Original Equipment Manufacturing (OEM). Products are used as an assembly part for the production of new cars; products are supplied to the automobile manufacturer.
• Original Equipment Service (OES). Products are used as an original replacement during the lifecycle of the car; products are supplied to the official dealer network of the automobile manufacturer.
• Aftermarket (AM). Products are used as a replacement during the lifecycle of a car, but products are widely supplied to universal wholesalers.
There are large differences when it comes to product characteristics between OEM and AM brake pads since the aftermarket is even more price oriented compared to the OEM products. AM friction formulations often include cheaper ingredients; the most expensive ones (including Twaron pulp) are removed on a regular basis. For Teijin the OEM and OES segments cover 90-95% percent of the aramid sales volumes. As already mentioned AM brake pads have to achieve the same level of performance on the European market, but the differences between AM and OEM pads are in the lifetime (increased wear rates) and comfort behaviour (increased noise, vibration, and harshness (NVH)).
Regarding the competition for Twaron pulp in the automotive brake pad market, a distinction between direct and indirect competitors can be made. Direct competitors are other aramid pulp manufacturers, including DuPont (U.S) and Kolon (Korea). Besides these, small enterprises from upcoming economies (China) are starting to produce aramid on a small scale. Indirect competitors produce other kind of materials competing with Twaron pulp. These materials are PAN pulp, glass fibres, and mineral fibres; however Twaron pulp is a unique material with properties that benefits to process ability as well to performance of brake pads. This combination of characteristics cannot be achieved by any other material (Hahn, 2000; appendix VII).
Social
Following recent market research (Research and markets, 24-8-2011) the global automotive products aftermarket is driven by the increasing social awareness of using environmentally safer products. In recent years environmental awareness became a worldwide issue, and is translating itself also towards the automotive industry. This trend
28 is also stimulated with tax regulations by the government in the automotive sector, as also mentioned in the political factors section.
Also the global trend in the automotive industry is to strive constantly for more comfort and performance for the end user (Research and markets, 24-8-2011).
In the automotive brake pad market product requirements vary extremely per region, based on the different needs from consumers (Honeywell, 25-07-2011). In the European market, where performance and sporty driving experience are favoured, low-metallic pads are popular because of their high friction coefficient and comfort at high speeds. The relatively high wear of both brake disc and pad are the trade-off here, which becomes visible due to friction dust forming on the rims. On the other hand, in America and Asia, the focus is rather on comfort and the avoidance of brake dust, resulting in the usage of NAO pads offering excellent NVH performance. Also pad and disc wear is reduced and service life is longer. The trade-off here is that NAO pads show less braking performance due to their lower coefficient of friction (Chan & Stachiowak, 2004). From a global perspective, NAO brake pads are becoming more popular also in Europe according to Federal Mogul (Appendix VII).
Technological
There are several technological trends affecting the automotive brake pad market, and will have an effect on the use of Twaron pulp in brake pads. The increasing sales volume of electric and/or hybrid vehicles, which is partly stimulated by the government, has several effects on the automotive brake pad market because brake systems will change. The first one is regenerative braking, a system that is used in emerging trend in electric and hybrid vehicles to convert the kinetic energy gained during braking into electric power for the batteries of those vehicles (Brake energy recuperation strategy, 11-08-2011). In this way the system replaces the function of a conventional brake system partially, but the conventional system is still needed because of the following reasons:
• Regenerative braking is less effective at low speeds. Practically, the system is not able to stop a vehicle completely.
• A back-up system is needed when regenerative braking system fails.
• If maximum capacity of storage for electrical power is reached, regenerative braking is not effective from then and the dynamic braking system takes over. The effect of using regenerative braking is that dynamic brake systems and brake pads are still needed in new cars, but the lifetime of brake pads will increase having a negative influence on the sales volumes in the AM segment (Appendix VII).
According to Federal Mogul there will be a trend towards noise reduction in braking systems, especially in electric and hybrid vehicles. Because electric and hybrid vehicles produce less engine noise compared to conventional cars, brake noise becomes more recognizable for consumers. Brake pads have a strong influence on the amount of noise produced during braking; therefore Federal Mogul is putting efforts in the development of more quiet brake pads. According to them, an effect of having brake pads with higher comfort behaviour is that the wear rate of brake pads possibly increases, resulting in a compensation for the lost sales volumes caused by regenerative braking.
According to TMD Friction there is an emerging need to reduce the weight of brake pads. Because brake systems are at the end of a vehicles axle, its weight has strong influence on the driving behaviour and affects directly acceleration and deceleration. (Automotive braking: materials and development, 11-08-2011). According to TMD Friction, the weight of a brake pad can be reduced either by replacing heavy materials such as metals by lighter materials, or by decreasing the wear rate of a brake pad so that less friction material has to be used to achieve the same lifetime.
4.1.2 SWOT Analysis
