Crosslinking with malonate blocked isocyanates and with melamine resins

Automotive clearcoats with improved acid etch resistance are being formulated using a combination of a dialkyl malonate blocked polyisocyanate, a melamine crosslinker, and an acrylic polyol,^1,2 These coatings contain lower levels of melamine crosslinker compared to conventional acrylic/HMMM systems and show excellent acid etch resistance. We explored the reaction mechanism of this complex crosslinking system and found explanations for the good chemical resistance properties. Presented at the 25th International Waterborne, High-Solids, and Powder Coatings Symposium, February 18–20, 1998, New Orleans, LA. Science Rd., Norwalk, CT 06852; E-mail: AlexHe@Kingindustries.com and Wblank@Kingindustries.com.     

Morphology of hybrid coatings based on polyester, melamine resin, and silica and the relation with hardness and scratch resistance

The morphology of hybrid coatings based on polyester, melamine resin, and various amounts of silica has been investigated, and the hardness and scratch resistance were determined. By increasing silica content, an increase of silica particles in size and number was observed. Small silica particles were preferentially present at the surface. The influence of the silica content on the K?nig hardness, indentation hardness, and elastic modulus was minor. The improved scratch resistance determined for a hybrid coating with 11.4 wt% silica, compared to a similar organic coating without silica, was attributed to small silica particles preferentially present at the surface. Presented at the 26th International Waterborne, High-Solids, and Powder Coatings Symposium, February 10–12, 1999, New Orleans, LA. Dept. of Polymer Chemistry and Coatings Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands. Materials Division, Dept. of Materials Chemistry and Coatings, P.O. Box 595, 5600 AN Eindhoven, The Netherlands.     

Investigation of the effect of precoalescence or postcoalescence crosslinking on film formation, properties, and latex morphology

Latexes have many product applications including functioning as a binder in coatings. For many years, coatings researchers in industry as well as in academe have been exploring various modes of crosslinking latexes. Quite often, the goal of preparing crosslinked latexes is to upgrade film properties relative to the film properties of uncrosslinked latexes. In the present report, the synthesis and properties of crosslinkable acrylic latexes prepared with either an internal crosslinker (1,3-butylene glycol dimethacrylate)—“precoalescence crosslinking”—or an external crosslinker (adipic dihydrazide)—“postcoalescence crosslinking”—at various levels of crosslinking were studied. For postcoalescence crosslinking, diacetone acrylamide was copolymerized into the latex to provide sites for subsequent reaction with adipic dihydrazide. Fundamental properties of films cast from the two types of latexes were systematically compared. These properties included gel content, dynamic mechanical properties, nano-indenter hardness and modulus, stress–strain properties as well as the characterization of latex morphology by atomic force microscopy (AFM). In addition, some specific end-use properties were determined. This study assesses the effect of type (precoalescence or postcoalescence) and level of crosslinking on the film formation process and the resulting fundamental and end-use properties as well as resulting latex film morphology. Presented at 2007 FutureCoat! Conference, sponsored by Federation of Societies for Coatings Technology, October 3–5, 2007, in Toronto, Ont., Canada.     

Testing accelerated weathering tests for appropriate weathering chemistry: Ozone filtered xenon arc

Ftir spectroscopy has been used to follow the weathering chemistry of a HALS and UVA free polyester/urethane and a HALS and UVA free acrylic/melamine clearcoat cured on silicon wafers and subjected to exposure in Florida, Arizona, and in a number of accelerated weathering tests. All accelerated tests except EMMAQUA-NTW, ozone filtered xenon arc, and 3M Proprietary exposures distort the polyester/urethane’s weathering chemistry relative to its Florida and Arizona exposure weathering chemistry. Distorted weathering chemistry was attributed primarily to spectral power distribution mismatch between artificial radiation and sunlight. Experiments were initiated with an ozone filtered xenon arc radiation source whose spectral power distribution matches sunlight with great fidelity in the 290–400 nm region. Presented at the 80th Annual Meeting of the Federation of Societies for Coatings Technology, October 30, 2002, in New Orleans, LA. Ford Research Laboratory, P.O. Box 2053, MD3182, Dearborn, MI 48121. Retired.     

Mechanism of TiO2/ZnO instability in latex paints

A strong interaction between titanium dioxide and zinc oxide in latex paints has been recognized for decades, yet the harmful consequence of this interaction—paint instability—remains an issue for many coatings manufacturers. An investigation into the chemical and physical changes that occur during paint aging has revealed the mechanism of this instability. The role of the TiO₂ pigment grade was further explored, providing an understanding of the gel mechanism and stability performance. Presented at the 80th Annual Meeting of the Federation of Societies for Coatings Technology, October 30–November 1, 2002, in New Orleans, LA. Chestnut Run Plaza 709, P.O. Box 80709, Wilmington, DE 19880-0709.     

Dimer acid structures. the thermal dimer of methyl 10-trans, 12-trans,linoleate

Thermal dimerization of the conjugated 10-trans, 12-trans linoleate (250C, 5 hr) produced a dimer whose structure is shown to be that of the Diels-Alder reaction between two molecules of monomer, with one molecule acting as diene, and either one of the two double bonds of the second molecule acting as dieneophile. This produces four skeletal isomers of a tetrasubstituted (1,2,3,4) cyclohexene structure with α-β unsaturation on one chain. The isomers formed depend on whether the 10 or the 12 double bond acts as dieneophile, and whether the monomers add “head to head” or “head to tail.” Evidences for the structures include chemical analyses, ozonolysis, nuclear magnetic resonance, IR and UV spectrometry and particularly mass spectrometry of the distilled dimer, of the completely hydrogenated dimer, and of the aromatized dimer formed by catalytic dehydrogenation. The hydrogenated dimer can be separated into two components by TLC. These are probably related to “head to head” vs. “head to tail” addition. Presented at the AOCS Meeting, New Orleans, 1964. Journal Series No. 366.     

Two-component high-solid polyurethane coating systems based on soy polyols

Soybean oil based polyols—soybean oil phosphate ester polyols (SOPEPs)—having varying hydroxyl content and viscosity were prepared as low cost and low-VOC polyols for coatings applications. These SOPEPs were used as the hydroxyl component of “two-component polyurethane (2K-PU)” coating compositions and their film properties were studied. Blends of commercial polyester polyol and SOPEP in varying proportions were also used to formulate PU coatings. Their film properties were studied and compared. We found that SOPEP can be used as the sole hydroxyl component or as the reactive diluent for polyester polyols in 2K-PU coating systems. SOPEP, is derived from a relatively inexpensive and renewable resource and the use of SOPEP can substantially reduce VOC and cost of PU coating formulations. Presented at the International Waterborne, High-Solids, and Powder Coatings Symposium, New Orleans, LA, February 2002.     

Search for new industrial oils. XII. Fifty-eight euphorbiaceae oils,including one rich in vernolic acid

Seed oil ofEuphorbia lagascae Spreng. contains 57% ofcis-12,13-epoxy-cis-9-octadecenoic (vernolic) acid. The amt of trivernolin in the glycerides of this species indicates random or restricted random distribution of the vernolic acid. Seed from 57 additional species in the Euphorbiaceae were analyzed for oil and protein contents and also for fatty acid composition of the oils. Iodine values (I.V.) of the oils ranged from 87–221. Among these oils, samples were encountered with as much as 76% linolenic, 77% linoleic or 84% oleic acid. Presented at the AOCS in New Orleans, 1964. A laboratory of the No. Utiliz. Res. & Dev. Div., ARS, USDA. ARS, USDA.     

High-strength,high-modulus fibres made from linear polymers: principles of fabrication,structure, properties,and use

The current types of ultrastrong and high-modulus fibres made from linear fibre-forming polymers — structure, principles of fabrication, properties, and basic areas of application — are examined. Most of the attention is focused on carbocyclic and heterocyclic para-aramid fibres, whose production capacities have reached 60,000 tons a year, the features of their structure and properties and areas of application. High-strength fibres made from other types of aromatic polymers (poly-p-phenylene benzobisoxazoles and thiazoles, polyarylates, polyvinyl alcohol, ultrahigh-molecular-weight polyethylene) are also briefly examined.     

Development of halogen‐free flame‐retardant thermoplastic elastomer polymer blend

Ethylene‐propylene diene rubber (EPDM) and isotactic polypropylene (iPP) blends have widest industrial applications that require a degree of flame retardancy. Halogen‐free intumescent technology based on phosphorous salt is a significantly advanced approach to make the polymer flame‐retardant. Both ammonium polyphosphate and ethylenediamine phosphate are important intumescent compounds. Their combination with carbonific and spumific agents were studied in binary blends of EPDM/PP. The polymer system was vulcanized online during melt mixing. Intumescent flame‐retardant polymer systems exhibit good flame‐retardancy with optimum comparable physiomechanical, electrical, and fluid resistance properties, including lower smoke emission, which is essential to protect people because the visibility remains unaffected in the event of fire. Pronounced charring and intumescent effect appear to enhance the flame‐retardancy of the polymers. Possible expected intumescent mechanism is proposed based on the nonpyrolysis mechanism for the flame‐retarded polymer and the intumescent components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 407–415, 2004     

α-Oxidation of α-hydroxyfatty acids in rat brain. Possible involvement of an α-peroxylactone

Combine—but not individual—microsomal and supernatant fractions obtained from rat brains not only consume oxygen but also provoke emission from added chlorophyll. These results are consistent with literature data (Levis and Mead,J. Biol. Chem. 239, 77 [1964]) for trapping of radioactive¹⁴CO₂ following addition of α-hydroxy-[1-¹⁴C]stearic acid. The most plausible explanation for emission is the interaction of chlorophyll with an α-peroxylactone. An intermediary α-peroxylactone in α-oxidation is consistent with other available data (Salim-Hanna, Campa and Cilento,Photochem. Photobiol. 45, 849 [1987]; Campa, Salim-Hanna and Cilento,Photochem. Photobiol. 49, 349 [1989]) and, on chemical grounds, provides a feasible route to the final products.     

Search for new industrial oils. XIII. Oils from 102 species of cruciferae

Seed from additional species of Cruciferae have been analyzed for crude protein, oil and fatty acids in the oil. Oils were like those reported earlier from other crucifers, except forCardamine impatiens which is unique among known seed oils because it contains some 25% dihydroxy acids. Erucic acid is present (0.3–55%) in about three-fourths of the 102 samples. Eicosenoic acid is a major constituent (32–53%) in four species and monohydroxy acids (45–72%) in another four. Linolenic acid occurs (2–66%) in oil of all species. Presented at the AOCS meeting in Chicago, Ill., October 11–14, 1964. A laboratory of the No. Utiliz. Res. and Dev. Div., ARS, USDA. ARS, USDA.     

Control of film defects in solventborne high-solids coatings: The non-additives vs. a new additives approach

Acetylenic based surfactants have long found utility in compliant coatings such as waterborne systems and are demonstrated here to enhance performance of solventborne high solids systems. Three new additives are shown to reduce surface defects such as craters and orange peel in conventionally spray applied polyester and epoxy paints. Important to this new additive technology is the lack of adverse effect on physical properties, recoatability, and durability of the applied coating. Also discussed are the theory and background of the origins of surface defects with emphasis on the influence of additives on paint rheology, compatibility, and surface tension. Presented at the Latin American Coatings Show, August 27–28, 1997, Mexico City, Mexico by Joel Schwartz and the 5th International Exhibition of Paint Industry Suppliers, September 15–17, 1997, Sao Paulo, Brazil, by Frank Lee. 7201 Hamilton Blvd., Allentown, PA 18195. 109 Lukens Dr., New Castle, DE 19720.     

Development of technology for nonwovens with antimicrobial and aromatic properties

New organosilicon modifiers — oligoethoxysiloxanes — were synthesized for textile fibres and their properties were investigated. It was found that nonwovens made of fibres modified with the new oligomers have bacteriostatic or bactericidal and aromatic properties as a function of the type of modifier. __________ Translated from Khimicheskie Volokna, No. 2, pp. 24–26, March–April, 2006.     

Confocal Raman microscopy study of the melamine distribution in polyester–melamine coil coating

Hexamethoxymethylmelamine, a common crosslinker used in combination with polyester resins to prepare thermosetting coatings, can self-condense during curing and in theory build up regions with high crosslink density (melamine enrichment). This distribution may affect such properties as the “local” glass transition temperature and structural heterogeneity and thereby modify formability, stain resistance, and weatherability. The self-condensation regions have not previously been observed in detail so their distribution in the film is unclear. Confocal Raman microscopy (CRM) has been used to characterize the melamine distribution in three polyester–melamine paint systems: one clear and two pigmented coil coatings. Both the surface mapping and depth profiling features of CRM were used to perform a 3D analysis. The depth profiling of the clear coating was performed in a nondestructive way, but due to the opaque nature of the pigments, cross sections of the pigmented coatings were prepared in order to facilitate the analysis of the melamine distribution through the film thickness. Melamine-enriched zones were found on the surfaces of all three samples. They appeared to be approximately spherical with diameters of around 5 μm. It was also observed from the cross sections that the melamine-enriched zones appeared as “particles” distributed randomly through the coating. The Raman spectra collected at these regions show significantly higher triazine ring band intensity. All of these findings confirm the hypotheses constructed over the past 20–30 years. This paper was awarded Second Place in the 2008 FSCT Roon Awards competition held as part of the FutureCoat! conference sponsored by the Federation of Societies for Coatings Technology, in Chicago, IL, on October 14–16, 2008.     

Surfactant behavior and its influence on the viscosity of associative thickeners solutions, thickened latex dispersions, and waterborne latex coatings

Surfactants, varying in their chemical composition and hydrophobic behavior, are used in the formulation of a waterborne coating. These differences influence their aggregation in micellar structures, their interaction with associative thickeners, and in particular, the synergies present in their competitive adsorptions on the disperse phases in a waterborne coating. Adsorption of HEUR thickeners on latexes and the ability of surfactants to displace them from those surfaces is an important variable in the dispersion’s viscosity. With large particle latexes, viscosity increases arise primarily from the network built through the interaction of HEURs with surfactants in the aqueous phase. Fluorescence is used to verify the mechanism by which surfactants enhance associative thickener viscosities. That is best achieved with nonionic surfactants, because of their synergies with large hydrophobe HEURs at low concentration. With decreasing latex particle size the adsorbed species is an important contributor to the dispersion’s viscosity through its contribution to the latex’s effective volume fraction increase and when the size of the adsorbed HEUR is matched to the separation distances of the latex at 0.25 volume fraction. Achieving controlled shear-thinning behavior in small particle size latex paints with the economic constraints on the amount of HEUR required to obtain 90 KU viscosities are discussed. Presented at the 80th Annual Meeting of the Federation of Societies for Coatings Technology, October 30–November 1, 2002, in New Orleans, LA. Polymer and Coatings Dept., Fargo, ND 58103.     

Hydrogenation of linolenate. VIII. Effects of catalyst concentration and of temperature on rate,selectivity, andtrans formation

The effects of catalyst concentration and of temperature on linolenate selectivity,trans formation, and rate of hydrogenation have been studied for a commercial electrolytic nickel catalyst. Results obtained with an equimixture of linoleate and linolenate, following the procedure previously described, are presented as isometric drawings, which cover the experimentally practicable temperature ranges from 70–230C and nickel concentration from 0.05–10%. Whereas the rate of hydrogenation depends upon both temperature and catalyst concentration,trans formation is essentially a function of temperature while selectivity is little influenced by either parameter. Presented at the AOCS meeting in New Orleans, La., 1962. A laboratory of the No. Utiliz. Res. & Dev. Div., ARS, U. S. D. A.     

Crosslinking vs. interdiffusion rates in melamine-formaldehyde cured latex coatings: A model for waterborne automotive basecoat

Designing optimal formulations for automotive waterborne basecoats can be fairly complex, often requiring knowledge of events that occur at the molecular level. The ultimate performance of the coating can depend upon the success with which this knowledge is applied. We examine a system in which an aqueous dispersion of an acrylic latex with -OH functionality reacts with a melamine derivative when heated. We use fluorescence-labeling and energy transfer measurements to obtain information on the relative rates of crosslinking and interparticle polymer diffusion in these films. We show that temperature and particle morphology play an important role in the development of film properties. Finally, these energy transfer experiments provide information on the location of the melamine-formaldehyde resin in the dry film before the onset of crosslinking. This system can serve as a model for waterborne basecoat development in many automotive applications. Presented at the 1998 Annual Meeting of the Federation of Societies for Coatings Technology, on October 15, 1998, in New Orleans, LA. Department of Chemistry, 80 St. George St., Toronto, Canada M5S 3H6. Finishes Division, 377 Fairall St., Ajax, ON Canada L1S 1R7.     

Structure/property relationships in flexible alkoxysilane automotive coatings

Flexible automotive coatings are susceptible to scratch and mar damage, especially during finishing and assembly operations. One-component (1K) flexible clearcoats exhibit very good scratch and mar resistance, but unfortunately suffer from poor durability and environmental etch resistance. Two-component clearcoats offer improvements in both etch and durability, but at the expense of scratch and mar. In this paper, the concept and properties of 1K flexibilized silane clearcoats for use on automotive plastics will be introduced and their structure/property relationships examined as they apply to scratch and mar. The role of coating crosslink density, toughness, glass transition temperature (T_g), and surface profile on the scratch damage of coated plastic substrates will be described. In addition, a new scratch methodology, termed Scratcho, is utilized to determine relative scratch performance and is compared to conventional scratch resistance testing. Results to date indicate that hardness, as affected by the glass transition temperature, and crosslink density, as it contributes to higher essential work values, both affect resultant scratch propensity of the flexible coatings. The relative ranking of different coating systems employing alternate crosslinkers (e.g., isocyanate and melamine) is also presented and compared to the newly developed silane crosslinked coatings. Presented at the 28th International Waterborne, High-Soids, and Powder Coatings Symposium, Feb. 21–23, 2001, in New Orleans. LA. 377 Fairall St., Ajax, Ont., L1S 1R7, Canada. 401 Southfield Rd., P.O. Box 6231, Dearborn, MI 48121-6231.     

Unusually high levels of eicosatetraenoic,eicosapentaenoic, and docosahexaenoic fatty acids in palestinian freshwater sponges

The fatty acid composition of three freshwater sponges—Ephydatia syriaca, Nudospongilla sp., andCortispongilla barroisi—were studied. Twenty principal fatty acids, and unusually high levels of eicosatetraenoic (5,8,11,14–20:4 up to 10.1% of the total acid mixture), eicosapentaenoic (5,8,11,14,17–20:5 up to 11.6%), and docosahexaenoic acids (4,7,10,13,16,19–22:6 up to 11.8%) were detected. The only demospongic acid found was 5,9,17-hexacosatrienoic acid (1.8–3.7%).