Toagosei Annual R&D Report “TREND” – Issue No. 10

OXT-211 (POX) and OXT-213 (CHOX) are colorless, transparent, low-viscosity monofunctional oxetanes for cationic UV curing and thermal cationic curing. In a UV-curable epoxy system, they can serve as cationic curable resin components, cationic curable additives, epoxy resin additives, reactive diluents for epoxy, low-viscosity epoxy additives, UV coating additives, or UV adhesive additives. Their viscosities are 13.8 and 6.7 mPa·s at 25°C, and both are compatible with cationically curable epoxy resin and common organic solvents.

Unlike radical UV curing, cationic curing enables oxygen-inhibition-free thin-film curing in air, with no oxygen inhibition at the surface. Dark cure and post cure can continue after irradiation, while cationic ring-opening polymerization supports low-shrinkage UV resin design and curing-stress control; actual low curing shrinkage depends on the full formulation. Photo-DSC testing showed that epoxy addition shortened the time to maximum heat release and increased the heat-release rate, indicating faster cure response in mixed oxetane–epoxy formulations and a route to improve cure speed in cationic epoxy UV curing.

The cured formulations combined toughness, flexibility, and elongation of approximately 120–310%. They showed favorable plastic adhesion to PC, PMMA, and PET, plus adhesion to treated steel and aluminum. At suitable blend ratios, OXT-211 coatings on PET film showed no curling after UV curing. Low residual stress and stress relaxation during later-stage epoxy crosslinking support use as a UV resin adhesion promoter and in low-stress UV adhesive, low-warpage UV resin, and coatings for adhesion to difficult substrates. The plastic and metal data may also guide bonding dissimilar substrates, although joint strength was not tested. OXT-213 reduced brittleness in an organic–inorganic hybrid resin that maintained high storage modulus up to 200°C and about 70% transmittance at 400 nm after 1,000 hours at 150°C, indicating potential for heat-resistant cationic resin and high-adhesion hard coatings.

ARUFON US Series is an alkoxysilyl-functional reactive plasticizer for sealants, developed as a liquid acrylic oligomer and plasticizer for modified silicone sealants. Produced by high-temperature continuous polymerization, it provides a high-solids, solvent-free route to a weather-resistant sealant plasticizer. Its alkoxysilyl group co-crosslinks with the modified silicone base resin during moisture curing, helping retain the plasticizer in the cured network and reduce extractable low-molecular-weight components. This makes the US Series a candidate for non-migrating plasticizer design, bleed-resistant sealant additives, stain-resistant sealant plasticizers, and long-life building sealants.

Building sealants must combine workability with flexibility so exterior wall joints can follow movement without peeling, rupture, or water leakage. Conventional plasticizers can bleed to the surface at high loadings, soften the surface, and cause staining. In the reported modified silicone sealant formulations, US-2 delivered low modulus and 890% elongation at break, making it suitable as a low-modulus sealant plasticizer and flexibility modifier for sealants. US-1 provided higher modulus and strength for adhesive-type applications. By changing the number of alkoxysilyl groups, formulators can adjust modulus and elongation without changing plasticizer loading.

Reactive incorporation improved gel fraction and bleed resistance. US-2 showed much lower color difference in the contamination test, while both US Series grades retained physical properties after 1,500 hours of QUV exposure; US-2 also showed no cracking after 400 hours of SUV testing. These results support use as a durable sealant plasticizer, building sealant additive, long-life sealant additive, and sealant formulation plasticizer for exterior sealants requiring weather resistance, waterproofing, airtightness, low modulus, flexibility, and resistance to bleeding and staining. The US Series therefore expands sealant formulation design from low-modulus flexibility to higher-modulus adhesive-type performance.

KESMON NS-231, KP-240 and KS-210 are aldehyde-focused inorganic-composite deodorants developed as chemical adsorbent deodorants and odor-control additives for formaldehyde and acetaldehyde. Their active amine component reacts chemically with aldehydes to form stable Schiff bases, while a porous inorganic carrier increases contact area, accelerating odor adsorption and improving low-concentration odor removal. Compared with activated carbon, this chemical adsorption mechanism provides strong aldehyde VOC control at elevated temperature and supports odor re-release prevention.

NS-231 is a powder-type heat-resistant deodorant with heat resistance up to 160°C and additional performance for basic gases such as ammonia. Repeated-loading tests showed an acetaldehyde deodorization capacity of approximately 50 mL/g and a formaldehyde capacity of approximately 80 mL/g. At an initial acetaldehyde concentration of 100 ppm, NS-231 and KP-240 reduced the gas to an undetectable odor level within minutes. Almost no aldehyde captured at room temperature was re-released at high temperature, making the series suitable for applications requiring rapid deodorization, sustained effect, heat resistance, and minimal odor re-release.

KP-240 is a 40% aqueous dispersion designed for aldehyde deodorization, with heat resistance up to 210°C and good handling for spray coating and dipping. KS-210 is a transparent, nanoscale liquid grade with 10–30 nm particles and heat resistance up to 210°C; it can provide low-haze deodorizing treatment and may be deposited on some substrates without a binder. Application studies demonstrated suppression of formaldehyde and acetaldehyde emissions from felt and particleboard. A car-mat formulation combining NS-231 with an acidic-gas deodorant also reduced acetaldehyde, ammonia, and acetic acid from cigarette smoke. These properties support use in automotive interiors, textiles and felt, wallpaper, flooring, paint, building materials, air-conditioner filters, and air-purifier filters where a high-performance aldehyde odor adsorbent additive is required.