Attack of the artillery fungus on vinyl siding

The artillery fungus, Sphaerobolus stellatus, ejects dark‐colored spores for a distance of several meters. These are enclosed in an adhesive layer comprised of carotenoid pigments. On exposure to sunlight, the pigment layer resinifies and develops a strong bond to vinyl siding capstock. The damage is compounded when the homeowner removes the bonded spores abrasively, destroying the protective capstock layer. Strategies to protect vinyl siding or to defeat the microorganism are discussed. J. VINYL. ADDIT. TECHNOL., 11:63–64, 2005. © 2005 Society of Plastics Engineers     

Formulations for vinyl house siding: History,present, future

In the early 1960s, vinyl house siding was first commercialized. The colors were pastels and included white, green, yellow, and gray. All siding tended to bleach and fade (oxidize) to an extent where medium and dark colors were unacceptable, since the fading is more noticeable in deeper colors. All the early siding was made from cubes on single-screw extruders. Powder compounds were first introduced in the late 1960s, as was twin-screw extrusion. At the same time higher processing temperatures were used on, both twin- and single-screw extruders. That led to a well-fused and tougher product. Formulation changes reduced bleaching and fading and permitted such medium-depth colors as tan, gold, beige, blue, and olive. This technology allowed rapid growth in the vinyl siding industry in the late 1970s. Surface distortion (oil canning) was recognized as a potential problem with the early gray color and recognized as a major problem with dark colors; it was resolved only by understanding the fundamental principles involved. Another major problem was the fading in dark colors and here again extensive research into the principles of weathering led to the use of a thin, highly weatherable capping as a cost-effective solution. For the future, many technical developments can be expected in this rapidly growing market. However, judging by the occasional withdrawal of a formulation from the market, and by an occasional homeowner complaint, present performance in several properties must be judged as just adequate. For this market to continue its rapid growth, future performance should be better than today's. This can be accomplished without hurting economics by careful understanding of all parameters involved. Formulation changes will allow better performance. Standards must be raised to control product performance, especially surface distortion and color stability in darker colors, and to insure retention of physical properties after long-term weathering.     

Enhanced weatherability of exterior PVC building products

Poly(Vinyl) Chloride (PVC) is used extensively as a material for the growing building‐products market. The color preferences of consumers for markets such as vinyl siding have forced the industry to seriously reconsider the use of PVC especially for the medium‐to‐dark color palettes, where the performance is critical. Organotin mercaptides have always been the stabilizers of choice in the U.S. market because of their inherent outstanding heat‐stabilization properties. On the other hand, this technology is also known to be a compromise between processability and weathering characteristics. In a market that drives for excellence, all additives must be optimized to meet the final performance requirement. Organotin carboxylates and specifically maleates have long been known for excellent weathering but have not been used extensively in the industry owing to less‐than‐optimum intrinsic heat stabilization efficiency, and in some cases, troublesome lachrymatory properties. A new generation of organotin maleates has been successfully developed to address both issues. This paper describes the improved lachrymatory behavior of the new technology compared to standard organotin maleates and also shows its outstanding weathering performance in PVC capstock compared with conventional organotin mercaptide during natural aging.     

Effect of iron compounds (oxide,salt, or complexes) on poly(vinyl chloride) thermal and photochemical stability

The color requirements for vinyl siding have drastically evolved over the last decade and have moved toward medium to dark colors. Therefore, manufacturers are exploring new ways to modify their formulations in order to improve weather-ability of these challenging colors. Examination of some of the PVC additives typically used in these formulations has led to some interesting revelations about the performance of iron-containing pigments, which are extensively used in darker colors. A quick weathering test was designed to evaluate the effect of iron in PVC formulations, and this test clearly demonstrates the correlation between iron content and PVC photodegradation.     

Fourier transform infrared micro spectroscopy mapping. Applications to the vinyl siding industry

Fourier transform infrared (FT-IR) micro spectroscopy is a powerful analytical technique capable of yielding high quality information with a spatial resolution as low as 10 microns. When coupled with an automated mapping stage it can offer unique evaluation capabilities. This paper describes a number of applications of FT-IR micro spectroscopy mapping to the vinyl siding industry. Examples will focus on determining, in single sample mapping experiments, the compositional changes associated with capstock to substrate transition and evaluating the degradation species and level observed during weathering exposure throughout the thickness of the siding panel.     

A novel impact modifier system for vinyl siding and profile substrate

The use of a newly developed ABS impact modifier in coextruded vinyl siding and window profile substrate is discussed. Considerations of toughness at room and low temperature, output, reduced lubricant levels, and weatherability of the finished siding are reviewed. Actual outdoor weathering results are presented, along with long-term heat aging tests, showing the modifier to have good property retention characteristics.     

New developments in profile extrusion expand the applications for plastics in the building industry

The potential market for plastics in the building industry is discussed with particular emphasis on vinyls. Equipment advances for co-extrusion and complex profiles are described. The use of capstock co-extrusion is proposed as a route to dark-color weatherability of PVC siding and building products. The transfer of European technology is suggested.     

Vinyl windows in canadian construction—a 20 year success story

The Canadian development of vinyl windows is described. The comparison of competitive window construction materials is made. Canadian standards and test methods are reported. A large increase in the market for PVC windows is projected for Canada. The availability of dark color windows by the capstock process, both from PVC-wood and PVC-aluminum composites, will stimulate this market.     

UV stabilizers: Their effects on vinyl compounds

Poly(vinyl chloride) (PVC) is the polymer of choice in a wide variety of applications on account of its comparatively low cost, high chemical resistance, good mechanical properties and electrical insulating capabilities. The even wider application of the material has been restricted by its low thermal and photolytic stability. This paper reviews the various light degradation and stabilization mechanisms that have been postulated recently for PVC. The importance of the thermal stabilizer system to the photostabilization of the material is also stressed. Finally the market opportunity for a cost effective UV stabilizer system for rigid PVC is discussed emphasizing the versatility that such a product would give to the vinyl siding manufacturer.     

Effects of process temperature on the weathering performance of rigid poly(vinyl chloride)

Elevated process temperatures can accompany current high extrusion rates of rigid poly(vinyl chloride). Various colored weatherable siding compounds were studied in the processing temperature range of 193°C to 227°C. The extruded compounds showed only minor color shifts due to increased melt temperatures. Outdoor exposure through four years in Arizona, Florida, and Ohio demonstrated typical color change but did not exhibit significant color shift relating to the initial processing temperatures. The samples extruded at elevated melt temperatures did demonstrate reduced impact strengths prior to outdoor exposure. Florida‐exposed and Ohio‐exposed samples lost impact strength throughout five years of exposure, with the samples processed at higher temperatures continuing to show lower impacts over time.     

Weatherability of rigid vinyl siding

Vinyl siding is described as a product in the early maturity stage of business development. The competitive position of rigid vinyl siding vis-a-vis other products is discussed. Total weathering exposures from point sources not usually thought of are reviewed. Methods of control for weathering caused changes as well as resistance evaluation are covered. The impact on the industry of the voluntary product standard PS55-72 is mentioned.     

Weatherability of plastics compared at different exposure locations

The mechanisms of the weathering of plastics are often initiated by damaging radiation from the sun or by the hydrolysis of ester, carbonate, or amide groups in the polymer. The Arizona exposure is sunny and dry, while the Ohio exposure is less sunny, wetter, and has more acid rain. Arizona emphasizes ultraviolet light exposure; Ohio emphasizes hydrolysis. This paper examines the weatherability of vinyl, ABS, acrylic, and SAN/EPDM polymers in these two locations. Color retention, original impact, and impact retention are evaluated.     

Fourier transform infrared micro spectroscopy mapping studies of weathered PVC capstock type formulations. II: Outdoor weathering in pennsylvania

FTIR micro spectroscopy coupled with mapping techniques is a powerful methodology to evaluate dimensionally dependent changes such as those encountered in PVC weathering processes. It is based on the complexity and specificity of the infrared spctrum and the dimensional resolution of the microscope. This paper will outline a systematic FTIR study of changes observed during outdoor photo degradation of PVC siding capstock formulations, as a function of exposure time and TiO₂ level. The results are compared with previously obtained accelerated QUV data. Profiles through the thickness dimension were analyzed to identify degradation species and depth distribution.     

Evaluation of the ASTM D7869-13 test method to predict the gloss and color retention of premium architectural finishes-I

A recently developed xenon arc-based accelerated weathering cycle, ASTM D7869-13, has been validated for automotive and aerospace coatings, but its ability to predict the gloss and color retention of premium architectural finishes has not yet been evaluated. We review new weathering data comparing the performance of poly(vinylidene fluoride) (PVDF) architectural finishes in south Florida exposure as well as several accelerated exposure methods including ASTM D7869-13. ASTM D7869 accurately reproduced Florida rank order gloss and color retention trends for coatings made with PVDF-acrylic blends and inorganic pigments, as well as the gloss and color changes seen in Florida for 70% PVDF masstone coatings made with a number of single organic pigments. However, the D7869 cycle has difficulty predicting the rank order of rutile TiO₂ grades for the gloss retention of PVDF coatings in Florida, as well as the magnitude and direction of color fade from organic pigment degradation in organic pigment/inorganic pigment blends. One open question that remains is whether the ASTM D7869 cycle might have some utility for industry standard or specification purposes, if the test is limited to specific reference colors or more ideally to specific reference pigments.     

Dichroic nanocomposites based on polymers and metallic particles: from biology to materials science

Dichroic nanocomposites change their colors when they are viewed through a turning polarizer. In the case of polymer matrices containing inorganic nanoparticles, this color effect originates in anisotropic structures of inorganic moieties, such as uniaxially oriented linear assemblies of spherical nanoparticles or parallel oriented nanorods. The orientation of the particles or particle assemblies, respectively, is induced by the polymer matrix, either through oriented elongated hollow spaces or drawing. Matrices based on biopolymers (e.g. cellulose, polypeptides, chitin) as well as synthetic polymers (e.g. polyethylene, poly(vinyl alcohol)) have been employed. The dichroic colors have been generated so far mainly by silver or gold particles (including nanorods), but also other metals and occasionally also semiconductors (metalloids). Notably, dichroism is also disclosed in optical absorption spectra recorded with polarized light. Dichroism in biopolymer‐based objects with incorporated nanoparticles has been exploited for the cognition of biological fine structures, while dichroic films with technical polymers as matrices have been considered as optical switches in bicolored liquid crystal displays and authenticity cachets for documents, banknotes and packaging films. In this context, micropatterning of dichroic nanocomposites, which has been achieved by local heating procedures of materials composed of metal nanorods, is also of interest. © 2017 Society of Chemical Industry     

Synthesis and corrosion protection performance of polydiphenylamine

In recent years, the conducting polymers are used in organic coatings as a replacement of chromate based pigments. The effectiveness of polydiphenylamine (PDPA) in the vinyl coating towards the corrosion protection of steel in acidic environment has been found out. The polymer PDPA was synthesized by chemical oxidation of diphenylamine by ammoniumpersulfate in hydrochloric acid medium. The polymer was characterized by FTIR and XRD. The corrosion protection performance of the PDPA containing 0–5% in vinyl coating on steel in 0.1N HCl has been assessed by electrochemical impedance spectroscopy. Coatings containing more than 3% PDPA are found to offer excellent corrosion protection of steel in acid media due to redox property of PDPA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Volatiles released during the weathering of PVC

Volatile organic compounds and organochlorine species liberated by UV exposure of poly(vinyl chloride) (PVC) siding samples have been identified and preliminary quantification made. These volatiles included those remaining in a PVC sample after weathering or laboratory UV exposure and which could be released by thermal desorption. In addition, by using a flow-through cell and granular carbon adsorbents, volatile species directly desorbed during laboratory UV exposure were measured. Total directly desorbed organochlorine compounds were about 1/20 of the weight of hydrogen chloride as measured by conductometric analysis, Quite similar products were observed from old (～1984) and current (1995) commercial siding formulations. Observed volatile compounds are proposed to come from the TiO₂-controlled photo-oxidation of both PVC and its additives such as impact modifiers.     

Exploring color attractiveness and its relevance to fashion

Many studies have been conducted on the phenomenon of color preference, with the aim of identifying the key color preferences. Most of the previous studies have been placing blue in the most preferred position and green-yellow in the least preferred position. This study was conducted online and aims to showcase new color preference trends in the digital age. The colors selected for this study were based on the colors most frequently mentioned in previous color studies. Here, we show an evaluation using 14 Pantone colors as stimuli on the sample of (N = 146) participants based on pairwise adjectives (attractive-unattractive). Principal component analysis and other multivariate statistics were used to examine participants' color attractiveness. In addition, gender and age were examined to determine if they had an impact on color attractiveness ratings. Results show that participants tend to prefer distinctive colors (black, pink, yellow), but there are slight differences in preferences that could be related to the influence of gender and age.     

Dark time yellowing of white rigid vinyl outdoor weatherable compounds

White PVC siding which has been exposed to sunlight will after removal from the sunlight develop a darker color (yellow-brown). The longer this sample remains unexposed to sunlight the greater the color development. Testing has indicated that one or more photochemical mechanisms are occurring during this color development. A sample which appears yellow upon arrival at the home location after outside exposure can be re-whitened by re-exposing the sample to sunlight. Drastic color change will occur within a short period of time, usually less than 72 hours. This sample will have attained its white color with little or no yellowing visible when an original unexposed sample is held next to it. Testing conducted at an Arizona test site has confirmed these theories. Six months and one year weathered white siding samples, when measured at the test site, both experimental and commercial, showed that when the weathered samples are removed from the test racks and tristimulus values are measured daily, marked color changes occur rapidly. This paper addresses data which indicate that color development does occur but only in the very thin surface (5 to 10 micron layer) of the weathered samples. If these samples are washed and the abrasive action is sufficient to remove the surface layer, color development will no longer occur during non-exposure to sunlight.