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Vacuums With Vision

Consumers demand for new features creates material challenges for vacuum OEMs.

Consumers have indicated that there’s nothing quite so satisfying as seeing a dust-filled canister after an hour’s worth of vacuuming. In turn, vacuum cleaner manufacturers are searching for new solutions in plastics as they integrate clear windows and dirt sensors in their products.

Remaining on top of the trend, Bissell, Grand Rapids, Mich., has introduced a new addition to its ProHeart[TM] deep cleaning units. The ProHeat[TM] Clearview[TM] Plus upright deep cleaner has a clear window that lets users see how well the unit does its job. Additionally, its housing is a rich, chromatic plum accented by charcoal gray trim and knobs.

To get the color produced rapidly, Steve Darcangelo, senior buyer at Bissell, calls on Clariant Masterbatches, Albion, Mich. “The housing for the ProHeat[TM] Clearview[TM] Plus has seven different parts produced on seven different machines, and it is vital that all the colors match exactly,” explains Darcangelo. “They’re all made from the same base resins, so we’re not dealing with the complexities of trying to match colors across different types of resins, but it’s still a challenge.”

Jay Lindstrom, Clariant Masterbatches, notes that the vacuum cleaner market frequently changes color palettes. “Therefore, using masterbatches as opposed to precolored resins makes a significant difference,” he notes. “Using masterbatches and natural resin, appliance manufacturers reduce the chance of generating unusable inventory.”

Color and additive masterbatch technology allows for the production of plastic parts by combining natural resin and custom formulated masterbatches at the molding machine. The manufacturer can then purchase resin at competitive market prices and add masterbatch color and additives as needed. The alternative approach is to use precolored resins ordered in large quantities. Difficulties can arise with precolored materials; if the manufacturer changes the product color, there will be excess inventory of the old colored resin.

Clariant Masterbatches are marketed under five global trade names: REMAFIN[R] masterbatches for olefin applications, RENOL[R] masterbatches for non-olefin polymers, CESA[TM] standard and specialty additive masterbatches, HYDROCEROL[R] chemical foaming and nucleating agents, and OMNICOLOR[TM] multipurpose masterbatches.

Chemical resistance

Royal Appliance Manufacturing Co., Cleveland, was looking for chemical resistance when it selected Eastman Chemical Co.’s Eastar[R] copolyester DN004 for multiple parts of its new Dirt Devil Easy Steamer carpet cleaner. Based on previous success with the Dirt Devil Mop Vac, Royal Appliance used Eastar copolyester to mold components for the see-through dirty water recovery tank and nozzle and the accessory storage compartment door.

“The clean and dirty water storage tanks in carpet cleaners are exposed to powerful cleaning agents that can attack plastics and cause hairline cracks, which give the plastic a frosted appearance and can cause the plastic to shatter if subject to impact or stress,” says Terry Zahuranec, product engineer at Royal Appliance.

Terry adds that the material also had to withstand impact, as floor appliances typically undergo heavy use, and offer clarity.

The Easy Steamer is lightweight and compact yet holds nearly a gallon of fluid, requiring fewer refills. The carpet cleaner is easy to fill, maneuver, empty, and store. The motorized brush roll gently deep cleans all types of carpets and includes accessories to clean upholstery and carpeted stairs.

“Eastar copolyester DN004 is one of Eastman’s toughest materials,” notes Doris Hobbs, business market manager, Eastman, Kingsport, Tenn. “It also offers good flow properties, dimensional stability, and low shrinkage rates. It is used for appliance parts, medical devices, displays, and industrial recreation applications.”

Flexibility

Seeking a softer material for its Vision Sensor vacuum cleaner bumper, Royal Appliance selected Copley, Ohio-based Multibase Inc.’s Multi-Flex[R] TEA 4001-35.

The process of overmolding is increasingly used to produce a combination of soft and rigid parts. Therefore, it has become important for molders to find a soft material that adheres to the rigid insert. While this is easily accomplished for polyolefinic inserts, it is challenging to find an elastomer that adheres to engineered polymers such as acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), polyamide (PA), and others. Royal Appliance approved Multi-Flex[R] TEA 4001-35 for overmolding ABS to produce a soft bumper without primer or mechanical fastening devices.

This 35 Shore A TEA (thermoplastic elastomer alloy) is fully compatible with ABS. Its low durometer hardness provides good shock absorption. Multi-Flex TEA[R] 4001-35 also shows excellence scratch resistance and, unlike most rubber compounds, will not stain when coming in contact with painted surfaces. It can be over-molded by insert molding or processed with rotational molds. The alloy also adheres to PC, styrene acrylonitrile copolymer (SAN), Polypro-pionate, and other engineering resins.

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RELATED ARTICLE: Reducing Shock

Although lacking any see-through windows, the 340BVR series of blower/vacs, produced by Ryobi Outdoor Products, Chandler, Ariz., presented a challenge all its own: creating a handle that would dissipate static charge build-up.

Ryobi selected Stat-Kon[R] P, a statically dissipative nylon 6 composite from LNP Engineering Plastics, Exton, Pa., that bleeds off electricity from the unit’s engine.

“In blower/vacs, the problem of static discharge usually occurs in the vacuum mode where there is a lot of air, leaves, and papers being sucked up through a large tube,” explains Dean Bacalzo, project engineer. “Electrostatic discharge (ESD) builds up in the tube and the unit itself. And, because there is so much air and so much velocity being drawn into the unit, the buildup is quick and the shock quite high.”

Blower/vacs are designed with two handles–a main handle and an assist handle. The main handle is to hold the bulk of the unit, and the assist handle is used to direct the unit. “Since the assist handle is a place where your hand should always be touching and is close to the engine, we decided that this was the perfect point where we could bleed off electricity,” notes Bacalzo. “By using the Stat-Kon P composite for the handle, we were able to bleed off the charge from the engine so there is a steady trickle of electricity going from the unit into the user via the handle and back into the ground.”

Before choosing Stat-Kon P composites, Ryobi engineers evaluated several other materials. “The problem,” says Bacalzo,” was that over time, the static dissipative characteristics of these materials would disappear. For example, if we set these materials out in the sun or if they became hot, the static dissipative characteristics would diminish. With the Stat-Kon P composite, the static dissipative characteristics are inherent in the material, meaning they last over time.”

— C.J.

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