The term polymer refers to a large class of natural and synthetic materials with a variety of properties and purposes. Natural polymer materials include shellac, amber, cellulose, and biopolymers like hair, skin and part of the bone structure. Synthetic polymers include Bakelite, neoprene, nylon, PVC (polyvinyl chloride), polystyrene, polyacrylonitrile and PVB (polyvinyl butyral).

Polymers and advanced materials have replaced other traditional materials in innumerable applications, and like other materials, an unexpected failure can be costly, even catastrophic.

Failure Analysis for advanced and polymeric materials
Stork Materials Technology experts are experienced in conducting failure analyses of a wide range of advanced materials, including:

• Plastic failure analysis
• Composite failure analysis
• Rubber failure analysis
• Adhesives and sealants failure analysis
• Paints & coatings failure analysis

Different materials, different failure mechanisms, different methodologies
Failure analysis of polymeric materials offers a unique challenge because while the basic failure analysis sequence remains the same, the fractographic interpretation and analytical testing is very different from that used on metallic materials.

Combinations of properties and factors cause failure
The 3 most important properties of polymeric materials in a failure analysis tend to be: composition, molecular weight and structure, and the inherent visco-elastic nature of macromolecules. The failures associated with these materials are often the result of a wide variety of mechanisms and factors, such as:

• Exposure to chemicals (environmental stress cracking, chemical contact)
• Contamination
• Adverse environmental conditions in service (temperature, humidity, UV exposure)
• Molecular degradation (molding process, service conditions)
• Molding defects (inclusions, voids, knit lines)
• Stress concentration (design features, defects)
• Rapid Deformation (impact, snap fit assemblies)
• Extended Time Under Stress / Creep
• Fatigue Loading

Finding the cause of the failure
The failure analysis process begins with the determination of how and why the part failed. The real answer is provided in what can be done to prevent future occurrences. Stork Materials Technology experts understand this and provide real-life solutions to challenges related to polymeric materials.

Fybrel® (Polyolefin Synthetic Pulp), a Mitsui Chemicals Inc. novel creation, is a highly fibrillated fiber similar to wood pulp. There are three types available: Fybrel® E and Fybrel® UL, which are both made from polyethylene, and Type Y that is made from polypropylene. All are available in various grades in wet-lap (sheet) form. The material's characteristics include:

· Heat Sealability - A heat-sealable product can be obtained by mixing Fybrel® with wood pulp in the papermaking process.

· Excellent Thermal Moldability - Sheets containing Fybrel can be draw-formed, beautifully embossed, and heat printed. Calendering yields a product with an extremely smooth surface, and varying the heat and pressure can control permeability.

· Water Resistance - Paper-containing Fybrel has improved resistance to water and also repels water better. Heat processing further enhances these characteristics.

· Superb Dimensional Stability - Fybrel products have excellent dimensional stability due to their resistance to water.

· Superior Resistance to Chemicals and Oils - Fybrel is a polyolefin, so it resists attack by almost all chemicals-including acids and alkalis-and is resistant to oils.

· Outstanding Electrical Properties - Fybrel is an extremely good electrical insulator.

It is used in as a component in battery separators, disposable food trays and packaging, embossed paper and stationery (greeting cards), filter elements for filtration systems and heat sealing paper for packaging and tea bag paper.

For more information, please visit: http://www.mitsuichemicals.com/fyb.htm

French Mechanical Dryers are used for many synthetic rubber materials. Mechanical dryers normally will dry material that has been first dewatered to an 8-12% moisture by a mechanical screw press or expeller. Drying is accomplished by heating the polymer under pressure and then subjecting it to a flashing stage where the water is evaporated. Some residence time in a following conveyor will allow specification moistures and temperatures to be reduced.

TYPES OF FRENCH MECHANICAL DRYING PRESSES:

R-120 Extruder Dryer

This machine is a solid barrel extruder type dryer. Flashing takes place upon the material exiting from a die plate. The discharge material is in a porous pellet form that is easily final dried and cooled.

Our Model R-120 is a 10.25" diameter unit and has a capacity range of 2 tons/hr. to 8 tons/hr., depending on material. Our larger size 14" machine is available for even higher capacities.

Our R-120 was designed with the customer's input. We met with many synthetic rubber producers around the world to obtain their input on what features are desired in an expansion type dryer. We received excellent input, and our Model R-120 includes many features for low maintenance and flexible operation.

Vented Mechanical Dryer

Our vented mechanical dryer utilized an adjustable orifice to control pressure and temperature. This 360 degree annular opening is followed by an atmospheric open vent mechanism to allow the flashed moisture to escape. The material is then pumped through a die plate where the product is cut into a dry, solid pellet form. This style of dryer has been used for most grades of SBS, SIS, and SEBS materials for over 30 years. Our design has been continually improved over the years based on our many years of experience.

Our vented mechanical dryer offers versatility - it can also be used in the close vent mode in order to provide porosity in the pellet. This allows a producer to make product in either a dense or porous pellet form.

French Polymer Dewatering Presses are designed to accept a free-drained feed material in a 40-60% water content range and dewater the material by expression to a discharge moisture in the 6-12% range.

Commercial size machines are designed to meet the process requirements of the customer. Many models are available. The particular model best suited for the job will depend on capacity and type of material and amount of water to be removed:

• The capacity determines the diameter (7", 10.25", 14", 16", and 18" diameters are available). Capacity ranges of 500 kg/hr to 12 metric tons/hr. Gearbox and machine designs range from 150 hp to 1,500 hp.

• The type of material and amount of water to be removed determines the length to diameter ratio. Our machines can range from 3:1 to 6:1.

Features Include:

• French Cone Mechanism
• Proprietary shaft arrangement design and barrel construction
• Strong, heavy-duty mechanical design
• Shaft support on both ends
• High-quality spare parts
  

The Self-Adjusting Power Linear Bush

DELIVERING HIGHER LOAD CAPACITY AND LONGER SERVICE LIFE

Schaumburg, IL - (March 28, 2006) THK's new self adjusting type Power Linear Bush is the ultimate in linear bushing technology. The new power linear bush offers higher load capacity and longer service life compared to conventional linear bushings. THK's Power Linear Bush is engineered with cages that are made of a synthetic resin that continually lubricates the rolling elements. The Power Linear Bush also has a uniquely designed, hardened steel ball plate featuring a precisely ground groove that is slightly larger than the ball. This results in an increased contact area between the balls and the ball plate. Together these design features provide load capacities 3 times higher than conventional linear bushings and 27 times longer service life.

THK's Power Linear Bush has extremely smooth and quiet motion due to a uniquely designed ball retainer and outer sleeve. They are constructed of synthetic polymer, which is lightweight, low friction and highly wear-resistant. These characteristics enable moving parts to have rapid motion while requiring lower driving power thereby reducing energy costs.

The convex shape of the ball plate provides a pivot point at the center which allows a self-adjustment capability up to 0.5°. This self-adjustment capability eliminates any possibility of edge pressure caused by inaccurate machining, errors in mounting, or shaft deflection. Self-adjustment capability can compensate for inaccuracies in base machining, reducing installation time and costs.

The Power Linear Bush's ball plates are designated to float in the outer sleeve. This allows clearance between the balls and shaft to be adjusted according to application. The Power Linear Bush is designed to be fully interchangeable with conventional linear bushings.

APL, Inc uses the science of rheology for Medical Device Testing and Polyurethane material with the purpose of accurately modeling the melt flow of the materials being tested. Compliance is crucial to how your product will work specifically. This ensures that your final product will meet your specified FDA compliance requirements.

RHEOLOGY

• The study of deformation and flow. In other words, the study of the flow of materials that behave in an interesting or unusual manner. Examples of normal, familiar flow of materials would be, oil, water, air. Sir Isaac Newton, studied these materials and created laws of physics that explain why they behave and flow in a predictable way.

• Other materials behave in interesting or unusual ways. Examples of paint, foams, melt plastics, and other fluids behave in a different variety of ways. These materials do not fall into the Newtonian flow laws. The science of studying these types of unusual materials is called rheology. The scientists who study the mathematical relationships that describe the behavior of these unusual fluids are called Rheologists.

Associated Polymer Labs, Inc. incorporates this science of rheology for the purpose of accurately defining the melt flow of the materials being tested. This gives a more accurate, definable way to follow behavior of newly discovered and complex polymers and synthetic rubbers. When assisting a client, this type of testing would be crucial to define the temperature of manufacturing a certain polymer and cooling temperature and time to keep the integrity of the plastic/resins that is being used.

• If a material is being used in a medical application, certain specifications to keep the product certified are required. Manufacturing processes are crucial to keeping the integrity of the product.

• Associated Polymer Labs, Inc. uses RHEOLOGY and product knowledge to help clients keep within these guidelines, to make a superior product, with minimum waste, and low downtime. This can save the company time, money, and legal obligations from making a faulty product.

EXAMPLE:

• A medical device company inquired why they were having problems injection molding their catheter tips. They were having many problems with bubbles, voids and overall performance problems.

• APL tested and evaluated these catheter tips. APL was able to pinpoint the cause of the problems. The company then had the tools to locate the specific changes that needed to be made with the compounder and the manufacturing department. APL was able to identify the root cause of the problem and make corrections before product launch. Associated Polymer Labs, Inc. was able to save this medical company millions of dollars in failed product, and manufacturing time. APL now tests and certifies every lot from their compounder. The process was streamlined which now produces great income for this company.

APL CAN HELP YOU FIND YOUR ANSWERS. ASK US HOW!