Baking conditions

Aqueous dispersions are used in fiber bonding, paper coating, friction and abrasive appHcations, and laminates and wood bonding. PhenoHc dispersions improve the strength of latex-contact adhesive appHcations. Epoxy-modified phenoHc dispersions are prepared by dispersion of the phenoHc epoxy resin. The systems are used for baked primer appHcations and bonding requirements. Minimum baking conditions are 20 min at 150°C (25). 

The requirement for the achievement of UHV conditions imposes restrictions on the types of material that can be used for the construction of surface-analytical systems, or inside the systems, because UHV can be achieved only by accelerating the rate of removal of gas molecules from internal surfaces by raising the temperature of the entire system (i.e. by baking). Typical baking conditions are 150-200 °C for... 

Development and Application of Network Structure Models to Optimization of Bake Conditions for Thermoset Coatings... 

BAUER AND DICKIE Bake Conditions for Ihermoset Coatings... 

TABLE 5.2. Baking Conditions and Colors of Resulting SiOx Films for Samples 1-3... 

Material Film Bake Conditions Thickness M Planarization (%) 20 50 100 200 ... 

Film Planarization (%) Material Bake Conditions Thickness... 

P.R.119 is not resistant to overcoating however, no blooming has been observed at low pigment concentrations and typical baking conditions. The pigment is also used in emulsion paints, although exterior application is not recommended. 

These reactions form polymer melamine crosslinks (Ml and MIO), melamine-melamine crosslinks (M2, M3, M4, M5, M8, M9, and Mil) or Interconvert functional groups (M6 and M7). The Importance of the different reactions depends on the catalyst level and type, the bake conditions, and most Importantly on the structure of the melamine resin. Reaction Mil occurs only under basic conditions (used In the preparation of melamine-formaldehyde crosslinkers) and can be Ignored In coatings where acid catalysts are used. Reaction MIO Is slow compared to reaction Ml (5). The reactions Involving water probably make at most a minor contribution under normal bake conditions. The most Important reactions appear to be Ml for fully alkylated melamines and Ml and M9 for partially alkylated melamines. Reaction M4... 

Differences in Network Structure. Network formation depends on the kinetics of the various crosslinking reactions and on the number of functional groups on the polymer and crosslinker (32). Polymers and crosslinkers with low functionality are less efficient at building network structure than those with high functionality. Miller and Macosko (32) have derived a network structure theory which has been adapted to calculate "elastically effective" crosslink densities (4-6.8.9). This parameter has been found to correlate well with physical measures of cure < 6.8). There is a range of crosslink densities for which acceptable physical properties are obtained. The range of bake conditions which yield crosslink densities within this range define a cure window (8. 9). 

As discussed previously, an optional postexposure, predevelopment bake can reduce problems with the standing-wave effect in DNQ-novolac positive resists. However, such a postexposure bake step is indispensable in the image reversal of positive resists (37-41) and certain resists based on chemical amplification of a photogenerated catalyst (64-67, 77, 78). For both types of resists, the chemistry that differentiates between exposed and unexposed areas does not occur solely during irradiation. Instead, differentiation occurs predominantly during a subsequent bake. Therefore, to obtain acceptable CD control in these systems, the bake conditions must be carefully optimized and monitored. 

Thus, sensitivity depends strongly on the crosslink density, du, which is controlled by the fraction of crosslinkable units in the material and the extent of the crosslinking reaction during baking. In the present work, the number of crosslinkable sites on each copolymer was fixed so different methods of changing the crosslink density were explored. Three approaches were used 1) the extent of the crosslink reaction was controlled by varying the bake conditions, 2) the crosslink reaction was carried out to completion and then the crosslink density was modified by a subsequent process step, 3) the total number of crosslink sites was altered and the reaction was allowed to proceed to completion. 

The films were spun at 1250 RPN for 1 minute onto three-inch silicon wafers. The wafers were baked at 150 C for 1 hour in a convection oven. Film thicknesses ranged from 0.8 to 1.3 m. Pure PNNA films were also prepared using the same casting solvent mixture and baking conditions. 

The reactions may lead to the formation of dimers or polymers or may achieve cross-linking, resulting in an insoluble, infusible him (i.e., drying). Apparently, the dominant reaction path depends on the temperature. At room temperature, mostly C—O—C bonds are produced, whereas C—C bonds are predominantly formed under baking conditions. 

Although it may be difficult to control the extent of drying or baking in certain processes, these phenomena should be evaluated, and if they do occur, the cleaning process should be designed to remove those soils in the more difficult dried or baked conditions. 

PBOCST is thermally stable to ca. 200°C. Above 200°C, the polymer loses about 45% of its weight as carbon dioxide and isobutene (15). Diphenyliodonium and triphenylsulfonium hexafluoroarsenates are thermally stable to ca. 250° and 300°, respectively. (16,17) Consequently, the resist formulated from PBOCST and these salts is stable to the baking conditions required for formation of high quality spin coated films, and the formulations have a long shelf life when stored at room temperature under yellow light. 

The solvent extraction experiments coupled with DSC and FTIR data show that the degree of cure of these mixtures, under identical irradiation and bake conditions, is dependent on the concentration and nature (% acrylonitrile) of the rubber modifier. The sol fractions for PCI cured epoxy films with three different rubber modifiers (5), ETBN-13 (27% CN), ETBN-8 (17% CN) and ETBN-15 (KMTCN) at a range of concentrations are shown in Figure 2. The data show that a decrease in extent of cure occurs with increased rubber concentration and that this decrease (ETBN-13 > ETBN-8 > ETBN-15) may be correlated to the percent acrylonitrile in the rubber modifier. This is supported by the FT-IR spectra of two of these mixtures (IV and VI) as shown in Figure 3 and the quantitative measure of the extent of cure as a function of irradiation time for mixtures V (30% TBN-13) and VIII (30% ETBN-15) as compared to mixture IX (no rubber) silicon in Figure 4 (8). 

Liljeberg, H., Akerberg, A., and Bjorck, I. 1996. Resistant starch formation in bread as influenced by choice of ingredients or baking conditions. Food Chem. 56, 389-394. 

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