Rubber in Automotive

Approximately 500 - 600 application in the automobile involve the use of elastomer. These uses vary from model to model and from year to year. Automotive people are continully faced with material, design, process and cost decision in choosing elastomers to established performance goal. These goals can include durability, economy and meeting government regulation depending on the application.

Automotive standard for elastomer.
A complete rubber component standard is necessary for the following reasons

1. To ensure selection of material that meet requirement.
2. To prevent change in production material without the users's knowledge.
3. To correlate design requirement  with material properties.
4. To make certain that the material are commercially available.
5. To maintain uniform quality in production shipments.

The requirements of a rubber component specification are as follow:

1. Material requirement such as color , type of materials finished part quality.
2. Performance requirement such as density, tensile , elongation and tear.
3. Description of test methods including SAE, ASTM, and other laboratory procedure.
4. Construction requirement for composite materialsuch as hoses head gaskets .
5. Dimensional requirement , any information on tolerance or thickness of material referred to in the standard is required.
6. Sampling instruction , including sample size and number of sample to be submited.
7. Packaging instruction, to ensure clean, distortion-free part after shipment and storage.

Testing and quality control of foam rubber

Foam rubber is a consumer product. Therefore various national standards organizations have taken steps to ensure the production and marketing of good quality foam rubber . Important properties tested for quality control and their specification limits are given in that follow.

• Indentation hardness index

• It is the load in kilograms required to give an indentation  in the sample equivalent to 40% of the original thickness of the sample under specified condition. It is a measure of the load bearing capacity of the foam rubber. Foam rubber product are graded by indentation hardness such as Code A has 7-14 indentation hardness.

• Compression set

• It is a measure of state of cure of the foam rubber . The test consists of compressong the test piece under specified condition of time, temperature and constant deflation and noting the effect on the height of the released test sample.The compression set of the sample when determined by the first method shall not exceed 15% and by the second method shall noe exceed 5%

• The color of latex foam rubber shall be as agreed between the purchaser and supplier.
• Flexing test that involves submitting the whole sample to a continuous flexing with an indenter for 2,500,000 cycles at 4 Hz and measuring the loss in hardness and thickness.
• Aging test 

• The test sample of aging test is kept in an oven at 70 +/- 1 *C for 168 hr. Upon removal from the oven after 10 hr, the hardness is measured. The hardness of the test sample after aging shall not vary by more than +/- 20% of the value obthained with the unaged test sample.

• Metallic Impurities

• The copper and manganese content in the test sample shall not be more than 0.001 and 0.005% respectively.

How to used a waste rubber?

Regenerated rubber is often popularly known as reclaim rubber in the tires and rubber industry. This is becoming more and more popular with the increase in natural rubber and synthetic rubber prices. Regenerated rubber is a product obtained from waste and worn out vulcanized scrap. Use of reclaim rubber is already established in automotive tires, butyl tube. Energy recovery is one of the important processes of tires reclaim. Tires (once the steel wire is removed) have a relatively high specific heat value, as compare to coal. Worldwide energy recovery makes up one of the largest uses of reclaim tires. Test suggests that the use of waste tires as a substitute for coal result in lower emissions of nitrogen and sulfur. There has been a significant amount of reclaim tires used in cement kilns.

The rubber industry worldwide has focused mainly on the disposal of waste rubber rather than recapturing the economic value of the resources incorporated in the waste, historically the uses for waste rubber have been of low economic value, resulting in a low volume of recycling and stockpiling of tires. Tires are consider as the most visible of waste rubber product and their accumulation is increasing at an alarming rate worldwide.

There is an enormous potential for reclaim and reuse of rubber in developing countries. Whether rubber tires are reused, reprocessed, or used for making article for human use, the end result is there is less waste and less degradation of these materials which could cause harmful effects in our environment.

In Asian countries there has been a culture to reuse and to recycle all materials. Other than making reclaim rubber, scrap tires parts have also been used in shoe soles, slippers and in washers. Worn out tread have been nicely stripped off and used on the wheel of bull carts. Sidewalls of a tires are stripped off and knitted nicely with steel wire to make mats, mattresses and flooring products. Worn out bladders have been used in making flower garden and so on.

There is tremendous potential for the application of rubber crumb (powder rubber) in the construction of road. Crumb rubber may be used as : Fill material , In asphalt(wet and dry), As a crack sealant and in repair membranes.

What is rubber roll?

The application of rubber to the surface of metal cores to make rubber covered rolls generally referred to as rubber roll. The function of rubber roll in various application are diverse, demanding different properties from the rubber that is used. One of the the most extensive uses of rubber roll is in the control liquids by pressing or squeezing, as exemplified in the manufacture of paper and in the processing of metal, textiles, plastics, and leather. Such typical device as the press roll, the touch roll, the padding roll and the transfering roll.

Rubber roll are used for many conveying purposes such as feed rools and guide rools of various kinds, as used in the paper steel textile and plastic industries. The properties of rubber that are important for such application include elasticity, friction abrasion resistance and chemical resistance . In advantage resistance to solvents and plasticizer as well as resistance to heat are desired in application such as laminating, embrossing and coating.

The design of rubber roll involves considering of general factor such as the work place, the working condition, the desire performance and the required durability. The core is designed on factors such as the load, the speed and the the required precision. The core may be built the seamless, welded or cast pipe and may be made from mild steel, cast iron, stainless steel etc. It is almost possible to vulcanize soft rubber satisfactorily to the cast iron core because during vulcanization heat drives gases out the porous iron causing blisters in the covering and resulting in early service failure. To overcome this problem a layer of ebonite is applied to the core and before the soft rubber cover.

How to design tires compound

Customers demand quality products. This will be as true in the feature as it is today. Tire are also designed to meet spectrum of service and enveronment condition. Aricraft and earthmover tires are the most advanced global tires that are specific for service, vehicle and enveronmental condition. The key properties to design tire tread compound is abrasion, heat buildup , wet grip and tear strength. Other properties that required is ease of processing. Different methods are used to develop the wide range of compounds required. Some compounds have ralatively simple application requirements, and some call for very complex properties that come close to the limits of materials and compounds. There for the same development process is not required for every compound. Some compounds are developed simply by making small changed in existing compound . Both tire technology and compound technology are changing as a result of trial and error, and intuition to become more scientific and predictive.