Properties Of Cured Films Research Articles

Preparation and characterization of self‐emulsifying poly(ethylene glycol) methyl ether methacrylate grafted polyacrylate copolymers modified by waterborne polyester

AbstractThe high molecular weight polyacrylate self‐emulsifying emulsion with 20% hydroxyl monomer and 50% solid content was prepared. Waterborne polyester was used to modify the acrylate resin. Besides acrylic acid (AA) and methacrylic acid (MAA), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) was also used as functional monomer to stabilize the polymerization process and improve the properties of the emulsion. The effects of the amount of waterborne polyester (WP), ammonium persulfate (APS), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA), methacrylic acid (MAA)/acrylic acid (AA) monomer ratio, butyl acrylate (BA)/styrene (St) monomer ratio on the molecular weight, particle size, viscosity, storage stability, and cured film properties of the polyacrylate emulsion were investigated. The average molecular weight of the modified polyacrylate was up to about 2.5 × 104 g mol−1. The emulsion remained stable after 6 months at room temperature. Transmission electron microscope (TEM) images showed that the latex particles had core‐shell structure. The films cured with melamine formaldehyde (MF) resin showed excellent water resistance, adhesion, and hardness.

Next Generation Photosensitive Dielectric Materials for Advanced Packaging Applications

Hitachi Chemical DuPont MicroSystems (HDMS) is a supplier of photosensitive negative-tone polyimides (PI) and positive-tone poly(benzoxazole)s (PBO) for use as protection layers in semiconductor ICs or as dielectrics for re-distribution layers in Fan-in or Fan-out wafer level packages. These materials offer an easy manufacturing process as well as ensuring high reliability in semiconductor packages. Recently, design rules and structures for next generation packages are advancing in order to achieve higher end multi-functionality. In accordance with this trend, next generation PIs and PBOs need to be developed to address new challenges that include lithographic properties, in-process compatibility and end-use properties and, in this paper, the latest material sets developed by HDMS will be introduced for advanced packaging applications. The 1st material set is a low stress photosensitive PI designed especially as a protection layer in advanced process node semiconductor ICs where warpage reduction and better protection capability for fragile low-k layers are needed. The 2nd and 3rd material sets are designed as low temperature curable photosensitive PI and PBO for use as dielectrics in Fan-out wafer level package to provide good applicability with future device designs as well as high package reliability by improving resolution, cured film properties, adhesion, insulation reliability, and others.

Synthesis and characterization of an acid catalyst for acrylic-melamine resin systems based on colloidal unimolecular polymer (CUP) particles of MMA-AMPS

Colloidal unimolecular polymer particles (CUPs) based on poly(methyl methacrylate-co-2-acrylamido-2-methylpropane sulfonic acid) were synthesized and characterized and its potential for use as a blocked acid catalyst for curing of acrylic-melamine based resin systems were evaluated. These CUPs were synthesized by the process of water reduction of acrylic copolymers and had zero volatile organic content (VOC). The curing performance of CUPs was evaluated by way of pencil hardness, micro-indentation hardness and solvent resistance measurements. These sulfonic acid containing CUPs catalyzed the curing of acrylic-melamine systems effectively and were found to provide final resin properties comparable to the commercially used blocked acid catalysts. On a molar equivalent basis, the amount of CUP catalyst required for the final cured film properties was lower than the commercial blocked acid catalyst. NMR analysis confirmed that the commercial acid catalyst leached out of the cured film when exposed to water for 24 h while the CUP catalyzed coating did not.

Preparation and Characterization of UV-Curable Cyclohexanone-Formaldehyde Resin and Its Cured Film Properties

UV-curable cyclohexanone-formaldehyde (UVCF) resin was prepared with cyclohexanone-formaldehyde (CF) resin, isophorone diisocyanate (IPDI), and pentaerythritol triacrylate (PETA) as base substance, bridging agent, and functional monomer, respectively. The structure of UVCF was characterized by Fourier transform infrared spectroscopy (FT-IR),1H-nuclear magnetic resonance spectroscopy (1H-NMR), and gel permeation chromatography (GPC). The viscosity and photopolymerization behavior of the UV-curable formulations were studied. The thermal stability and mechanical properties of the cured films were also investigated. The results showed that UVCF resin was successfully prepared, the number of average molecular weight was about 2010, and its molecular weight distribution index was 2.8. With the increase of UVCF resin content, the viscosity of the UV-curable formulations increased. After exposure to UV irradiation for 230 s, the photopolymerization conversion of the UV-curable formulations was above 80%. Moreover, when the UVCF content was 60%, the formulations had high photopolymerization rate, and the cured UVCF films showed good thermal stability and mechanical properties.

Surface modification of electrospun porous scaffolds by S-ATRP grafting poly(ethylene glycol) methacrylate for tissue engineering

Colloidal unimolecular polymer particles (CUPs) based on poly(methyl methacrylate-co-2-acrylamido-2-methylpropane sulfonic acid) were synthesized and characterized and its potential for use as a blocked acid catalyst for curing of acrylic-melamine based resin systems were evaluated. These CUPs were synthesized by the process of water reduction of acrylic copolymers and had zero volatile organic content (VOC). The curing performance of CUPs was evaluated by way of pencil hardness, micro-indentation hardness and solvent resistance measurements. These sulfonic acid containing CUPs catalyzed the curing of acrylic-melamine systems effectively and were found to provide final resin properties comparable to the commercially used blocked acid catalysts. On a molar equivalent basis, the amount of CUP catalyst required for the final cured film properties was lower than the commercial blocked acid catalyst. NMR analysis confirmed that the commercial acid catalyst leached out of the cured film when exposed to water for 24 h while the CUP catalyzed coating did not.

Self-emulsifiable soybean oil phosphate ester polyols for low-VOC corrosion resistant coatings

A series of soybean oil phosphate ester polyols (SOPEP) was prepared by reaction of fully epoxidized soybean oil with phosphoric acid and simultanoeous hydrolysis in the presence of a polar solvent. The polyols were characterized by determination of acid value, oxirane number, hydroxyl value, molecular weight (GPC), and FTIR spectra. These polyols with varying amounts of acid phosphate groups could be self-emulsified to form aqueous dispersions after neutralization with organic base. These aqueous dispersion showed varying degrees of stability and their appearance ranged from opaque dispersions to translucent to clear solutions. Waterborne coating compositions were prepared using these aqueous dispersions as principal components and their thermally cured film properties were studied. it was found that by careful selection and formulation, SOPEPs can be successfully used for low-VOC waterborne coating formulations. SOPEPs with 3.5% phosphate ester content showed visibly superior corrosion resistance properties.

Study on novel heat-resistant aqueous dispersion based on modified poly(phthalazinone ether nitrile ketone)s

Poly(phthalazione ether nitrile ketone)s (PPENK), modified with NaOH, were studied in order to find a hydrophilic resin with could be used in heat-resistant water-borne coatings. The properties of hydrolysates — HPPENKa (0.5 hours), HPPENKb (1.5 hours) and HPPENKc (3.5 hours) — were measured by differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), contract angle (water) and solubility. The structures of the hydrolysates were confirmed by FIIR (Fourier transform infrared spectroscopy) and1H-NMR. The results indicated that the conversion ration of the nitrile groups and the glass transition temperature (79) of the hydrolysates increased, whereas the weight loss ratio of HPPENK decreased as the hydrolysis time was prolonged As expected, the hydrophificity of HPPENK improved greatly (eg when the CN conversion ratio was 93.82%, and the water contact angles decreased from 75.3° for PPENK to 54.4° for HPPENK). By studying the effects of the different reactions of the co-solvents, the reaction temperature and the NaOH concentration on the hydrolysis, it could be concluded that the optimal synthetic technology was of a 6M NaOH solution with DMAc (N,N-dimethylacetamide) as co-solvent at 120°C. Aqueous dispersions based on three modified resins were prepared and their storage stability was as follows: HPPENKc >HPPENKb>HPPENKa. In particular, the HPPENKc dispersion had no settling for more than 30 days and provided good film-forming. The cured film properties of HPPENKc were as follows: pencil rigidity (six hours), thermal impact resistance (300°C, 24 hours), and adhesion (grade 1). Curing agents were applied to the dispersion, such as hexamethoxymethyl melamine (HMMM), epichlorohydrin (ECH), triethanolamine, and glycerol, etc. HMMM and ECH provided excellent curing properties. The co-operating emulsification of (Span) sorbate and (Tween) polyoxyethylene sorbate could improve the stability of the HPPENK dispersion.

Effects of monomers on the properties of palm-oil-based radiation curable pressure sensitive adhesives (PSA) — a prepolymer method

Various low glass transition temperature ( T g) acrylate and methacrylate monomers were mixed with epoxidised palm oil acrylate (EPOLA) with the ratio of 50/50 prior to curing with electron beam (EB) irradiation. Methacrylate monomers such as dicyclopentenyloxyethyl methacrylate (DCPOEMA) and isobornyl methacrylate (ISBMA), although displaying relatively high adhesive properties were finally excluded from being further utilised as monomers for PSA because of a very slow curing speed. Literally, it is suggested that poorer adhesive performances of the cured films made from 50/50 : EPOLA/monomer mixture as compared to that of 100% monomer was attributed to the lack of compatibility between EPOLA and the particular monomers. Further compatibility investigations were continued using formulations prepared via the prepolymer route cured by ultraviolet (UV) irradiation and the results showed that several monoacrylate monomers with polar and non-polar groups exhibited high curing speed as well as good compatibility with EPOLA as shown by their cured film properties such as surface tackiness, peel adhesion and creep resistance. It is also suggested that these monomers were acting as surfactants for EPOLA which consequently enhance their compatibility upon mixing.

A kinetic investigation into the effect of silica properties on the photo-oxidation of a water based silica coating

Abstract Films prepared from a copolymer methyl methacrylate/butylacrylate system containing silica as a matting agent, have been the subject of an accelerated photo-oxidation study. An intensive FT–IR experiment was designed in which 13 different silica samples were carefully chosen in order that the effects of key silica properties on the rate of photo-oxidation could be determined. The properties where those effects were anticipated included metal ion content, coated or uncoated silica, particle size, pH, pore volume and silica type (fumed or gelled). To complete the study the effect of silica loading was also investigated. The rate of photo-oxidation was followed using reflectance FT–IR spectroscopy to monitor the change in concentration of key functional groups and also by measuring changes in the cured film properties. This study found that silica can influence the rate of photo-oxidation, the extent of which is dependent on key silica properties such as metal ion content and the contact area of the silica surface with the lacquer formulation.

Ultraviolet‐photocurable oligomer. II. Syntheses and cured film properties of ultraviolet‐photocurable BTDA‐based caprolactone multiacrylate oligomers

A series of ultraviolet (UV)-photocurable 3,3′4,4′-benzophenone tetracarboxylic dianhydride (BTDA)-based multiacrylate oligomers containing pendant glycidyl methacrylate (GMA) or glycidyl acrylate (GA) and caprolactone acrylate (Tone M-100) or caprolactone methacrylate (Tone M-201) were synthesized. The effects of the acrylic functional groups, the moles of GMA, and the molar ratio of Tone M-201 to Tone M-100 on their properties were investigated. The prepared photocurable oligomers were cured rapidly when exposed to UV or sunlight radiation without the addition of any extra photoinitiator or photosensitizer. The acrylate-type oligomer resulted in a lower thermal curing temperature and a fast curing rate. Increasing the moles of GMA or the molar ratio of Tone M-201/Tone M-100 on reaction led to a higher crosslinking density and resulted in film with higher Young's modulus, higher breaking strength, and lower elongation. The methacrylate type oligomer cured to a very hard but brittle film with higher Young's modulus and lower elongation. By contrast, the acrylate-type oligomer cured to a hard, tough film with lower Young's modulus and higher elongation. The film properties of the oligomers coated on steel plates were also investigated. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1625–1634, 1997

Ultraviolet-photocurable oligomer. II. Syntheses and cured film properties of ultraviolet-photocurable BTDA-based caprolactone multiacrylate oligomers

A series of ultraviolet (UV)-photocurable 3,3′4,4′-benzophenone tetracarboxylic dianhydride (BTDA)-based multiacrylate oligomers containing pendant glycidyl methacrylate (GMA) or glycidyl acrylate (GA) and caprolactone acrylate (Tone M-100) or caprolactone methacrylate (Tone M-201) were synthesized. The effects of the acrylic functional groups, the moles of GMA, and the molar ratio of Tone M-201 to Tone M-100 on their properties were investigated. The prepared photocurable oligomers were cured rapidly when exposed to UV or sunlight radiation without the addition of any extra photoinitiator or photosensitizer. The acrylate-type oligomer resulted in a lower thermal curing temperature and a fast curing rate. Increasing the moles of GMA or the molar ratio of Tone M-201/Tone M-100 on reaction led to a higher crosslinking density and resulted in film with higher Young's modulus, higher breaking strength, and lower elongation. The methacrylate type oligomer cured to a very hard but brittle film with higher Young's modulus and lower elongation. By contrast, the acrylate-type oligomer cured to a hard, tough film with lower Young's modulus and higher elongation. The film properties of the oligomers coated on steel plates were also investigated. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1625–1634, 1997

Solderable Polymer Thick Film Conductors for Surface Mount Technology

A new class of solderable PTF materials has been evaluated for SMDs on FR‐4 substrates. No etching or plating baths are required in this totally additive process. The materials are printed in the desired geometry, cured by heat or infra‐red followed by soldering and device mounting. The study examines processing variables and resultant cured film properties including solderability, conductivity and adhesion.