Applications of infrared spectroscopy to customer problems in the vinyl industry

Identifying polymers, additives and contaminants presents unique challenges. Fourier transform infrared spectroscopy (FT-IR) coupled with spectral searching techniques is a very efficient and powerful methodology to answer most identification questions. It is based on the unique IR spectrum characteristic of each compound. This paper outlines procedures employed in the identification of typical PVC formulations, starting with the resin and proceeding to impact modifier, process aids, lubricants, stabilizer system and fillers. The emphasis is on FT-IR microscopy as the most versatile approach requiring small samples and minimal to no sample preparation. Other commonly used FT-IR techniques are also outlined. Wet separation protocols, applicability and limitations as related to FT-IR analysis are discussed. Typical examples include vinyl siding, packaging and bottle formulations as well as contaminants often encountered in these formulations and raw materials.     

Superior balance of weatherability and impact performance with acrylic‐capped vinyl siding

Vinyl siding, particularly in darker colors, has to be durable and be able to retain most of its original color when exposed outdoors. As the color palette for vinyl siding has been expanding and more and more colors are being offered to the homeowner, the need exists to improve color hold. A new acrylic capstock polymer, based on core‐shell technology, which can be coextruded onto vinyl siding, has been shown to provide excellent color retention, with good processability, impact and impact retention, and suitable gloss. The properties of this new capstock polymer are compared to other choices for capping vinyl siding. J. VINYL ADDIT. TECHNOL., 13:26–30, 2007. © 2007 Society of Plastics Engineers.     

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.     

相容剂对PE基木塑挂墙板性能的影响

以木粉和废HDPE为主要原料,用挤出成型的方法制备PE基木塑挂墙板,试验研究了相容剂种类、相容剂加入量对木塑挂墙板性能的影响,通过性能测试和断面SEM分析,结果表明:添加相容剂M603的木塑挂墙板性能最好;MAPE加入量增加,弯曲强度和落锤冲击高度增加,吸水率降低,MAPE加入量8%~10%比较合适。     

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     

Rigid cellular PVC—the next house siding material?

The technology for extruding rigid cellular PVC has grown substantially over the past decade. Formulation additives, tooling, and processing expertise have made possible a variety of applications—relatively complex profiles, foam-core pipe, thermoformable foam sheet, and house siding. In the U.S. market, vinyl house siding is typically a relatively thin extrusion that is folded into a final shape that resembles wood cladding in appearance. An alternative to conventional form vinyl siding could be a foam structure that is thicker and stiffer than the solid form, and with a density similar to that of wood. This paper presents several performance advantages of rigid cellular PVC cladding in comparison to the current solid product, in addition to mentioning certain limitations that exist in the foam product that is produced with the technology available today.     

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.     

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.     

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.     

Dimensional stability of exterior building products

Dimensional stability problems such as warpage, bowing and other changes in shape and size may occur when exterior building products (siding, windows) are heated by the sun. This paper describes the effects of material properties such as coefficient of thermal expansion, heat distortion temperature, modulus, and heat build-up, caused by the sun, on dimensional stability of the exterior building products.     

Compound requirements for vinyl siding

Basic principles of good compounding for weatherable vinyl siding are discussed. Appropriate level of stabilizer is such that 50 percent of initial should remain after the extrusion process. Balanced lubrication is necessary. Judicious choice of pigments and impact modifiers is called for. The cited references give added substance to this review paper.     

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.     

Ignitability Analysis of Siding Materials Using Modified Protocol for Lift Apparatus

This paper reports on the ignitability of common siding materials that could be exposed to wildland fires. When exposed to brands or fires, structures will experience piloted ignition, which is requisite for sustained ignition involving burn-through and surface flame spread in various directions. In this study, the Lateral Ignition and Flame Spread Test (LIFT) apparatus (ASTM E1321 and E1317) was used to test various siding materials (plywoods, softwoods, and vinyl), some of which were painted, humidified, or sawed. A recently developed protocol provided useful, accurate values of the following thermophysical properties: surface emissivity, surface ignition temperature, thermal conductivity, and thermal diffusivity. Full consistency was achieved with independent literature values of these properties and can be used directly in the database of fire growth models.     

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.     

Shrinkage in rigid PVC profile extrusions

Shrinkage in PVC profile extrusions may have an effect on the end use performance (dimensional stability, mechanical properties) of the building products such as house siding and windows when they are heated by the sun. This paper examines the heat shrinkage tests being used in the industry, and most importantly, describes effects of the extrusion conditions such as melt temperature, shear rate, percent drawdown, and other variables on shrinkage in PVC profiles.     

Expanding PVC as a building material

Rigid vinyl foam can currently be found in applications such as profile, sheet, and foam core pipe, but it is still a curiosity in house siding and other wood replacement applications. This paper looks at the potential for vinyl foam as an alternative for wood, comparing its end-use capabilities. In addition, the various types of extrusion processes, and formulations, are compared, and the effect of certain types of formulation ingredients on density, surface quality, and other physical properties are described.     

合成油的开发与前景

根据世界能源消费结构多元化和化工原料多样化特点 ,参考国外近年来合成油的新技术动态 ,结合我国国情 ,建议在现有的合成氨或甲醇装置上增加侧线抽出合成气 ,副产高附加值的合成油产品。     

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.     

Rigid PVC formulation optimization using sequential simplex

A rigid PVC formulation was optimized for processing window and cost using sequential simplex techniques in combination with desirability functions. This optimization was performed on seven of the ten ingredients from a ‘standard’ siding compound with a relatively limited number of experiments. The processing window contour mapping technique was used to evaluate the effects of formulation changes. This was combined with the formulation cost by using desirability functions to give an overall response for the simplex to optimize. The basic mechanics of sequential simplex and desirability functions are described along with the results of the optimization.