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Laser Direct Structuring Material

U.S. Patent 9,074,070 (July 7, 2015), “Thermoplastic Composition for Use in Forming a Laser Direct Structured Substrate,” Paul C. Yung and Rong Luo (Ticona LLC, Florence, Kentucky, USA).

Portable computers and handheld devices with wireless communication capabilities require built-in antennas. These are based on conductive networks formed in plastic by laser direct structuring (LDS). However, plastic compound ingredients such as flame retardants impede the LDS process. Thus a need exists for a laser-activated thermoplastic composition having a high dielectric constant but still maintaining excellent mechanical properties and processability.

Yung and Luo developed a material containing a thermotropic liquid crystalline polymer, a dielectric material, laser-activatable additives, and a fibrous filler. This material can be readily shaped into a thin substrate, and conductive networks readily formed on it by the laser process. This material consists of 20-80 wt% of the thermotropic liquid crystalline polymer, 0.1-30 wt% of the laser-activatable additive, 1-50 wt% dielectric material, and 5-50 wt% fibrous filler. The thermotropic liquid crystalline polymer is based on naphthenic polyesters; the laser activators are spinel crystals with two or more metal oxide clusters; and the dielectrics are ceramic fillers such as barium titanate or carbon particles.

Heat-Resistant Copolymer Blends

U.S. Patent 9,062,193 (June 23, 2015), “Heat Aging Resistant Ethylene Vinyl Acetate Copolymer Composition and Process for Its Production,” Steven R. Oriani (E. I. Du Pont de Nemours and Company, Wilmington, Delaware, USA).

Oil-resistant ethylene vinyl acetate (EVA) copolymers are well-known synthetic materials formed by copolymerizing ethylene and at least 40 wt% vinyl acetate. These resins are used in wire and cable jacketing as well as in the production of automotive parts such as hoses and seals. Resistance to heat aging is necessary in under-the-hood applications, because they are exposed to temperatures above 160°C for hours, resulting in oxidative embrittlement.

There’s a need to improve the high-temperature resistance of these copolymers. Oriani developed heat-resistant EVA copolymer compositions consisting of a blend of EVA copolymer, peroxide-curable polyacrylate elastomer, and polyamide. When crosslinked with a peroxide, this EVA copolymer material has enhanced resistance to heat aging. For example, replacing one quarter of the EVA material by a blend of polyacylate elastomer and polyamide reportedly can provide over five times greater elongation at break after one week heat aging at 190°C—and one-fifth the usual change in Shore ‘A’ hardness. Furthermore, these advantages in heat aging are gained with no sacrifice in compression-set resistance.

High-Strength Composites

U.S. Patent 9,079,362 (July 14, 2015), “Apparatus for Manufacturing a High-Strength Composite Sheet Having Superior Embeddability, and Method for Manufacturing a High-Strength Composite Sheet Using the Same,” Hee-June Kim, Myung-Chul Park, and Hyun-Young Cho (LG Hausys, LTD., Seoul, South Korea).

More and more metal structures are being replaced with plastics, including recycled plastics, for reducing weight. However, recycled thermoplastic products produced by, for example, injection-molding are poor replacements due to insufficient strength and rigidity. The plastics must be reinforced to be effective replacements.

Kim, Park, and Cho manufactured a high-strength composite sheet by mixing peroxides with recycled plastics, then pressing the mixture into a reinforcement sheet. The plastic and reinforcement sheets are wound onto rolls and then unwound together, so the recycled plastic sheets surround the reinforcement sheet. The whole assembly is then pressed with heat and pressure to impregnate the reinforcement and form a uniformly crosslinked material.

Recycled resins can include polypropylene, polyethylene, polyester, polyamide, and acrylonitrile butadiene styrene (ABS), as well as thermosets and their mixtures. Peroxide loading is 0.5 to 4 parts per 100 parts, by weight, of the resin.

Biorenewable Monomers

U.S. Patent 9,080,011 (July 14, 2015), “Poly(Dihydroferulic Acid) a Biorenewable Polyethylene Terephthalate Mimic Derived from Lignin and Acetic Acid and Copolymers Thereof,” Laurent Mialon and Stephen A. Miller (University of Florida, Gainesville, Florida, USA).

Biorenewability refers to the use of a sustainable raw material supply from plants or other biological matter, generally through agriculture. Rather than growing biorenewable polymers, a more practical goal is to extract monomers from biorenewable products that mimic those from petroleum sources.

Mialon and Miller prepared a biorenewable thermoplastic, poly(dihydroferulic acid) (PHFA), which is said to be an effective polyethylene terephthalate (PET) mimic. It’s polymerized by step-growth condensation polymerization of acetyldihydroferulic acid, resulting in the PET-like polymer. PHFA monomers can be extracted from lignin, rice bran, or other biorenewable sources. In one example, vanillin is extracted from lignin and condensed with acetic anhydride to form acetylferulic acid, and reduced to acetyldihydroferulic acid with hydrogen. This is then polymerized by transesterification.

Converting Plastics to Oil

U.S. Patent 9,074,140 (July 7, 2015), “Apparatus for Thermolysis Waste Plastics and Method for Thermolysis Waste Plastics,” Daria Fraczak and Bartlomiej Samardakiewicz (Clariter IP S.A., Grand-Duche Du, Luxembourg).

Thermolysis can convert waste plastics into useful hydrocarbons. However, these conversion systems are large-scale and impractical for the small processor. Smaller, more economical systems are needed.

Fraczak and Samardakiewicz have developed smaller, efficient systems consisting of feedstock extruders, thermolysis reactors, external circulation loops, and product collecting systems. The collecting and separation system includes a condenser, a cooling system, a light fraction receiver with a gaseous product removing system, a crude heavy fraction receiver, and a vacuum evaporator.

This system reportedly is flexible and can accommodate feedstock changes, optimizing production. Using the extruder as a feedstock feeder reduces temperature differences between feedstock and reaction mixtures, ensuring system stability and reducing unwanted byproducts such as coke. Two-step product separation enables products with repeatable properties. A wiped film evaporator separates heavy oil and wax without product degradation, while gaseous products can be used as a fuel for heating.

Flowable Polypropylene

U.S. Patent 9,074,085 (July 7, 2015), “Heterophasic Polypropylene with High Flowability and Enhanced Mechanical Properties,” Saeid Kheirandish, Petar Doshev, and Claudia Kniesel (Borealis AG, Vienna, Austria).

In recent years, the demand for high-performance propylene-based plastics with enhanced mechanical properties and processability has grown as more metal parts are replaced with plastics. Polypropylene (PP) is a well-known resin for many applications. Compounding additives are used to optimize its most desired properties. However, compounding increases costs and property variation—and PP flowability remains a problem in processing.

Kheirandish, Doshev, and Kniesel developed a heterophasic PP resin blend produced by a single multistage process. Here, PP homopolymer is produced in a bulk reactor and, in a second stage, a polypropylene-ethylene/ alpha-olefin copolymer is produced in a gas-phase reactor mixed with the homopolymer. This process is said to be a low-pressure continuous process producing a flowable material with good properties, without needing additional compounding steps.

High Melt-Strength Polypropylene

U.S. Patent 9,074,062 (July 7, 2015), “Process for Preparing High Melt Strength Propylene Polymers,” Umasankar Satpathy and Ajit Behari Mathur (Reliance Industries Ltd., Mumbai, India).

PP has many attractive properties for many different applications, but it has low melt strength—making processes such as thermoforming difficult and costly. Satpathy and Mathur prepared high-melt-strength propylene polymers by blending base propylene polymers with 0.1 to 1 wt% of polyfunctional acrylate monomer with 10 to 50 ppm organic peroxide, plus 0.2 to 20 wt% stabilizers, acid neutralizers, antioxidants, or lubricants, as needed. The modified propylene polymers obtained reportedly have melt strengths 30 to 60% higher than the base propylene polymers.