Transparent acrylic copolymers

Photochemical Stability of UV-Screening Transparent Acrylic Copolymers of 2-(2-Hydroxy-5-vinylphenyl)-2 -benzotriazole... 

Process aids are added primarily to PVC-U (including foam) to improve fusion characteristics and melt flow during the processing stage. Addition levels are typically from 1-6 phr with resultant improvements in output and surface finish. Transparency can also be improved in clear formulations. Chemically, these products are high molecular weight methyl methacrylate and alkyl acrylate copolymers. 

Rhoplex [Rohm Haas], TM for aqueous dispersions of acrylic copolymers. White, opaque emulsions various grades differing in hardness, flexibility, adhesion, and tack of film some thermosetting. Produce colorless, transparent films with outstanding permanence, durability, adhesion, and pigment-binding capacity. 

Clear transparent foils, which are used as covers for documents, are in wide use as are polystyrene windows in letter envelopes. These may be directly scanned with the AFM and rescanned after irradiation. The changes are initially on the nanometer scale—and nanostructures can be formed and found quite easily. This has been done with a commercial styrene//-propyl-acrylate copolymer which was purchased in 1975 and which had abrasive... 

Figure 34. Atomic force microscopy surfaces of a styrene/i -propyl-acrylate copolymer transparent foil (a) before irradiation (b) after 2 h irradiation under vacuum. 

Acrylate rubbers such as poly (butyl acrylate) or poly (ethyl hexylacrylate) are characterized by better aging characteristics than polydienes. Ethyl hexylacrylate and acrylonitrile were grafted onto PVC in solution by R. G. Bauer and M. S. Guillord. They observed that this graft copolymer was transparent in contrast to a mere polyblend of PVC and an AN/acrylate copolymer. 

It was observed that these transparent 1.5/1.0-PVC/acrylic copolymer (1.5/ 1.0-2EHA/AN)-graft/blend films were somewhat more resistant to degradation from UV exposure than unstabilized homopolymer PVC (see Table VI). The graft/blend films retained clarity and were noticeably less prone to shrinkage in the Fadeometer where the service life was extended from 500 hrs for the control to 2000 hrs for the graft/blend films. 

A transparent PVC-acrylic copolymer product can be formed by polymerizing 2-ethylhexyl acrylate and acrylonitrile in the presence of a homogeneous solution of PVC using a free radical initiator. In contrast, products formed by the solution blending of PVC and a copolymer of 2-ethylhexyl acrylate and acrylonitrile were translucent to opaque. 

The transparent PVC-acrylic graft/blend products are somewhat more resistant to UV degradation than the parent PVC polymer and have physical properties which are of interest in film applications. These properties include improved tear strength over the PVC parent polymer and somewhat higher tensiles than are obtainable with the acrylic copolymer. 

While any plastic material, irrespective of its chemical composition and character, may be made into pipe or tubing, by far the greatest amount of pipe is made from thermoplastics (TPs) that are adaptable to extrusion processes (Chapter 5). Specialty pipe is made in small amounts from TS materials such as phenolic and polyester, but very large of commercial pipe is made from polyethylene, polyvinyl chloride, acrylonitrile butadiene copolymers, and acrylonitrile butadiene styrene types of alloys. Specialty tubing in relatively small amounts is made of acrylates and acrylate copolymers, as well as other transparent materials (Chapter 3). 

Degalan V 26 (Degussa, A.G., B.R.D.). This is a 90/10 (methyl methacrylate)-(butyl acrylate) copolymer. It mixes well with PVC and it does not affect its transparency, water absorption, and electrical properties. It is suitable to modify the rheological properties of impact-PVC. It shortens the plastication time of PVC mixtures and it improves their homogenization and the extrusion output. The addition of Degalan V 26 also improves the heat stability of PVC mixtures and increases the resistance of PVC-based products to heat distortion. 

Quantum yields and lifetimes of emission (fluorescence) as well as other principal rates of deactivation have been measured on 2-hydroxy benzophenone and 2-hydroxyphenyl benzotriazole derivatives. Polymerizable UV screening agents have been prepared and copolymerized with acrylics in order to obtain transparent films containing nonfugitive UV screening agents. Preliminary results of studies of photodegradation on these copolymers are also reported here. 

MMA is also used extensively as a copolymer with acrylates in latex paints and as a homopolymer in lacquers, since its transparent,... 

These polar copolyr ers are more transparent and. as a result of the presence of the polar acrylic acid moiety, have better adhesion to metallic surfaces than ldpb. The commercial copolymer, which is usually 50% neutralized to salts of sodium or zinc, is stiff and strong because of ionic crosslinking at room temperature, but it is readily proccssible when heated. 

Elastomeric graft copolymers of methyl methacrylate upon diene and acrylic rubbers were prepared by R. G. Bauer and co-workers. These elastomers are compatible with rigid methyl methacrylate-styrene copolymers of identical refractive index, yielding transparent polyblends. 

Copolymers of PE with vinylacetate, acrylic acid ester and methacrylic acid increase the heat sealability, adhesion to other materials and seal strength and they improve the polymer s cold resistance and transparency. EVA in the form of shrink films are well suited for meat packaging because of their relatively high gas permeabilities. 

The following TPs are the main thermoforming materials processed high-impact and high-heat PS, HDPE, PP, PVC, ABS, CPET, PET, and PMMA. Other plastics of lesser usage are transparent styrene-butadiene block copolymers, acrylics, polycarbonates, cellulosics, thermoplastic elastomers (TPE), and ethylene-propylene thermoplastic vulcanizates. Coextruded structures of up to seven layers include barriers of EVAL, Saran, or nylon, with polyolefins, and/or styreneics for functional properties and decorative aesthetics at reasonable costs.239-241... 

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