Impact modifiers: product lines reviewed.
AMOCO CHEMICAL COMPANY
Company's polybutenes improve impact resistance of many types of thermoplastics, including crystal PS, high-impact PS, PP homopolymer, and elastomer-modified PP. Polybutenes are clear and stable viscous polymers with low odor and resistance to thermal degradation, making them well suited for use in thermoplastics. Products are available in a wide range of viscosity grades.
In PS, polybutenes can improve impact resistance and melt flow. When polybutenes are used in place of mineral oil, the physical properties of PS are less affected and there is an improvement in the impact resistance.
In modified PP and in resin which has been modified with a thermoplastic elastomer (TPE), polybutenes are said to dramatically improve impact resistance. This suggests that polybutenes may be used to enhance impact strength and partially replace more expensive TPE.
ATOCHEM NORTH AMERICA, INC.
Offers its Metablen C series of MBS impact modifiers for use with rigid PVC products. A patented manufacturing process reportedly ensures consistency from lot to lot, guaranteeing a quality impact modifier that contributes to the uniformity of PVC compounds. Products are sanctioned by FDA as an additive for food-grade PVC. Each product is designed for specific applications, with no detrimental effect on heat stability, and are low in gels. Metablen C products are packaged in 20 kg polyethylene-lined bags, palletized.
Company also offers Durastrength 200, all-acrylic modifier for rigid PVC.
THE BFGOODRICH CO.
Company's Hycar RLPs are functionalized butadiene and butadiene-acrylonitrile liquid polymers, which enhance properties of epoxy, polyester, urethane, acrylic, and bismaleimide resin systems. Characteristics include impact/crack resistance, thermal stress resistance, flexibility, low-temperature property control, chemical/corrosion properties retention, and adaptability to co-cure or synthesis.
COLORADO CHEMICAL SPECIALTIES
Manufactures a line of liquid 1,2-polybutadienes and 1,2-polybutadiene-styrene copolymers for use as low-temperature impact modifiers in polyolefins, styrenics and TPE. Products are called Ricon and have application in PP, peroxide-cured PE, as cross-linking polymers, and also in TPE.
COPOLYMER RUBBER & CHEMICAL
Manufactures several types of elastomers for use in improving the impact resistance of a variety of thermoplastic resins. EPsyn brand EPDM is used for olefinics, NYsyn brand NBR and COPO brand SBR for styrenics, and TERsyn brand impact modifier for engineering plastics. NYsynblak brand NBR black masterbatches are used as combination impact modifiers/black concentrates for ABS.
Company's Customer Applications Development Center can provide technical service assistance and compound recommendations for both impact modification and thermoplastic elastomers.
DOW CHEMICAL CO.
Offers chlorinated polyethylene (CP), which is used as a weatherable modifier for rigid vinyls.
DU PONT CO.
Company's toughening technologies involve four major families of modifiers: ethylene terpolymers, ionomers, grafted polyolefins and elastomers. This broad range of technologies is key in optimizing compatibility between modifier and base polymer.
*Ethylene terpolymers provide impact resistance over a broad temperature range and particularly at low temperatures for a wide variety of thermoplastics and thermosets. In thermoplastics, ethylene terpolymers are said to offer excellent potential for improving the impact resistance of PVC, ABS, SAN, SMA, thermoplastic polyesters (including recycled materials) and polycarbonate. In PVC they offer two key benefits in addition to higher impact: 1) improved weatherability and 2) easier processing resulting from a reduction in melt viscosity. Weatherability is also improved in ABS. Thermoset applications include phenolics, polyesters and epoxies.
*Ionomers - Company's Surlyn ionomer resins provide low-temperature impact properties in nylon 6. In TPOs, ionomers enhance abrasion resistance and paintability.
*Specialty polyolefins and elastomers - In reinforced PP and PE compounds, company's Fusabond anhydride-grafted polyolefin modifiers improve toughness by increasing adhesion between reinforcements and the resin matrix. Another polyolefin, VLDPE (very low-density PE), has the potential as a low-cost toughener for filled and recycled PE materials.
*Thermoset elastomers - In TPOs, EPDM rubber is a standard modifier. In SMC and BMC, company's Neoprene rubber functions as both a low-profile additive and an impact modifier.
Manufactures Expancel line of expandable thermoplastic microspheres used as blowing agents and low-density fillers. Areas of application for Expancel as an impact modifier are thermosets, coatings and elastomers.
Microspheres create a syntactic foam with defined pore size, closed cell structure and resilient voids. The resilient nature of Expancel allows deformation without breakage, thereby improving impact resistance and stress.
Further applications are found in elastomeric materials where the resiliency of Expancel improves compatability between filler and binder material.
EXXON CHEMICAL CO.
Company's Exxelor brand modifiers are a family of polyolefin-based polymers which can be used to improve the end-use performance of a variety of thermoplastic resins. Exxelor modifier grades are available to improve both low-temperature impact down to -40 F and room-temperature impact properties.
A group of products in this family are functionalized and can be used to modify engineering thermoplastics, polyolefins, glass-reinforced and filled compounds, and alloys or blends of engineering thermoplastics and polyolefins.
Exxelor modifiers posses excellent thermal stability and long-term heat and weathering resistance. The functionality also lends itself to use as a modifier and compatibilizer for engineering thermoplastics.
Two new grades, PO 2011 and PO 2021, have been added to the Exxelor family. Developed to improve the impact and heat-distortion performance of mineral- and glass-reinforced polypropylene compounds, they reportedly act as compatibilizers in blends of PP and nylon. At levels between 3% and 5%, the new grades are said to improve heat-distortion temperature of reinforced PP by up to 45 F. Both modifiers can be used as compatibilizers in homopolymer and copolymer blends of PP and nylon up to a 50:50 ratio.
FIRESTONE SYNTHETIC RUBBER
& LATEX CO.
Company's Stereon line of block copolymers of styrene and butadiene are used for impact modification of thermoplastic resins. Stereon 721A and 730A are effective graft bases for impact enhancement of high-impact PS and ABS. Products are available in baled form and are usually incorporated directly into the polymerization stream. Stereon 840A is a pelletized, multiblocked copolymer that, when dry-blended with PS, PP or PE resins, will improve impact, flexibility, and tear strength. Stereon 840A can be used to upgrade regrind streams and provide impact improvement for degradable plastics. Stereon 900 is a high-styrene, pelletized copolymer designed to be dry-blended with 40-50% crystal polystyrene for extrusion and thermoforming of disposable drink cups, packaging, and medical devices.
GE SPECIALTY CHEMICALS
Produces the following impact modifiers for PVC and other resins:
*High-efficiency impact modifiers - Blendex 336 and Blendex 338 are high-efficiency ABS impact modifiers that contain a high percentage of rubber. Blendex 336 provides transparency and is also used in specialty PVC applications where a high degree of stress whitening is desired. Blendex 338 is more efficient than 336 and provides the best low-temperature toughness.
*Clear impact modifiers - Blendex 405, 420 and 467 are ABS modifiers that are designed to toughen the polymer without detracting from its optical properties. White used primarily in clear PVC film and bottles, it can also be used in engineering thermoplastics. In addition to PVC, Blendex products can be used to modify and toughen other polymers such as polycarbonate and polyesters.
*High-heat impact modifiers - Blendex 702 and Blendex 703 are impact modifiers based on alpha methyl styrene. These modifiers are used to upgrade PVC compounds and other polymers having marginal service temperature performance.
KANEKA TEXAS CORP.
Produces MBS/acrylic impact modifiers with the following properties:
*B-11A - Low impact, excellent clarity, noncrease-whitening.
*B-18A-1 - Medium impact, high clarity.
*B-22 - High impact, high clarity.
*B-28 - Excellent impact, medium clarity.
*B-31 - Medium impact, excellent clarity, noncrease-whitening.
*B-51 - Excellent impact, excellent clarity, noncrease-whitening.
*B-52 - Excellent impact and high clarity.
*B-56 - Ultra high impact, translucent
*B-58 - Ultra, ultra high impact, translucent.
PLASTIC & RUBBER DIV.
Baymod A, ABS powder modifiers, including products for both rigid indoor and exterior weatherable applications, provide improved impact resistance and heat distortion temperatures for PVC alloys used for injection molding and extrusion. Typical applications include business-machine housings, profile extrusions, and semi-flexible or rigid, calendered thermoformable sheets.
Baymod ethylene vinyl acetate copolymers can be used as weatherable impact modifiers for rigid vinyl extrusions such as window profiles, or as "permanent plasticizers" for flexible compounds that require improved extraction resistance and aging properties.
NOVA POLYMERS, INC.
Produces impact modifiers for ABS, HDPE, PP, PVC, and polystyrene/ABS blends under the trade name Novalene.
Novalene, an EPDM rubber, is suitable for use by molders and compounders of polypropylene and polyethylene and comes in a convenient dry-blending form. Company reports that the addition of Novalene in the prescribed amount, even to scrap, can raise Izod levels to the no-breaking point, even at very low temperatures. In general the Izod impact strength of pure Novalene is no-break at -20 F.
Novalor is a high-butadiene ABS powder for PVC and gives added impact strength and processability with less loading, according to the company.
ROHM AND HAAS CO.
Company's Plastics Products business offers its Paraloid family of impact modifiers for vinyls and engineering plastics. Product range includes:
*Paraloid KM-300 series - an all-acrylic line of weatherable impact modifiers for vinyl extrusions subjected to outdoor exposure.
*Paraloid BTA series - a line of methacrylate-butadiene-styrene (MBS) impact modifiers for toughness in PVC sheet, film and containers used in clear or opaque packaging.
*Paraloid HT series - acrylic-imide-based modifiers for improvements in heat distortion properties of both clear and opaque vinyl.
Also offered is a wide product range of Paraloid EXL impact modifiers designed for engineering resins. Included in the range are:
*EXL-3300 series - butyl-acrylate-based tougheners for polyesters and blends, PC and nylons.
*EXL-3600 series - MBS-based impact modifiers with high thermal stability for PC, PET, PBT, and blends.
*EXL-4000 series - imide-methacrylate products for blending with nylons, PC, SAN, ABS and polyesters.
SHELL CHEMICAL CO.
Company's Elastomers Business Center provides a diversity of SBS and SEBS block copolymers for the impact modification of PS, engineering thermoplastics, and alloyed products.
SBS Kraton D polymer series is used for impact modification of polycarbonates, PPO, and polyolefin blends. Kraton G 1901X, a functionalized polymer, is used for impact modification of engineering thermoplastics and for making polar and nonpolar polymers compatible. SBS and SEBS polymers are also available in specific grades as low-profile additives for the production of BMC and SMC parts; Kraton G 1855X provides a class-A automotive finish. A variety of company's developmental polymer products are available for sampling for the purpose of modification of a wide range of materials.