Hot-melt adhesives (HMAs) are thermoplastic materials that can bond various substrates by solidifying rapidly upon cooling from the molten state, and their modification with organosilicon compounds can result in crosslinking behavior, characteristic of gels. Organosilicon compounds are hybrid molecules that have both inorganic and organic components and can enhance the properties and performance of HMAs. The gel aspect of HMA with and without organosilicon modifiers can be considered in organosilicon-modified systems, the modifiers are often either sol–gel condensation products or their mechanism of action on the adherent surface can be considered of sol–gel type. The purpose of this manuscript is to present the current state of the art on the formulation, characterization, and application of HMAs and optimize their performance with organosilicon compounds for application in various industries such as automotive, construction, and photovoltaics. This review covers articles published within the period of 2018–2022. The article is divided into sections, in which information about hot-melt adhesives is described at the beginning. The following part of the presented review focuses on the composition of hot-melt adhesives, which takes into account the use of organosilicon compounds. The last part of this review outlines the future trends in hot-melt adhesives.

Polyoxymethylene (POM), polypropylene (PP), and poly(methyl methacrylate) (PMMA) have been blended with adhesive-grade ethylene vinyl acetate (EVA), propylene elastomer (VMX), isobutylene–isoprene rubber (IIR) and an acrylic block copolymer (MMA-nBA-MMA). The blends were prepared using a two-roll mill and injection molding. The mechanical properties of the blends, such as tensile strength, tensile modulus, elongation at maximum load, and impact resistance, were investigated. The water contact angle, melt flow rate (MFR), and differential scanning calorimetry were ascertained to evaluate the blends. The blend samples exhibited the following properties: all POM/EVA blends showed reduced crystallinity compared to neat POM; the 80% PMMA/20% MMA-nBA-MMA blend showed improved impact resistance by 243% compared to the neat PMMA. An antiplasticization effect was observed for POM/EVA 1% blends and PMMA/EVA 1% blends, with MFR reduced by 1% and 3%, respectively. The MFR of the PP/IIR 1% blend increased by 5%, then decreased below the MFR near the polymer for the remaining IIR concentrations.

The influence of organosilicon compounds on butyl sealant blends’ mechanical and processing properties was investigated, particularly under increased humidity conditions. The addition of (3-mercaptopropyl)trimethoxysilane (MPTES), (3-aminopropyl)triethoxysilane (APTES), vinyltrimethoxysilane (VTMOS), and (3-glycidoxypropyl)trimethoxysilane (GLYMO) to elastomeric blends containing butyl rubber (IIR) and polyisobutylene (PIB) was studied. Key rheological parameters, including Mooney viscosity and melt volume rate (MVR), along with mechanical attributes such as peel resistance and cone penetration, were evaluated. Results indicated that functionalized silanes enhance sealant cohesion when their functional groups interact with the matrix and form cross-links under humid conditions. The presence of unreacted silanes acts as a plasticizer, increasing MVR and reducing viscosity. A notable MVR increase, up to 109 mL/10 min, was observed for the APTES-10 system. The most significant mechanical property enhancements were observed in blends containing MPTES and APTES, resulting in increased cohesion and peel resistance. The findings of this research are of considerable practical relevance, demonstrating that the modification of rubber sealants with monofunctional silanes improves their cohesion, delamination resistance, and processability, thereby making these materials suitable for the production of more durable sealants.

This study evaluated how silicone release liners come away from butyl hot-melt pressure-sensitive adhesive (HMPSA) sealants. An application-specific integration peel test was conducted based on FINAT FTM 10 geometry. It kept the 180° geometry, the 300 mm/min crosshead speed, and the cN/25 mm reporting convention, but used 90 mm butyl-sealant strips in place of a standard reference adhesive tape. The reported values are therefore apparent/effective separation forces for the tested liner–butyl constructions, not standard FINAT datasheet release-force values. Three double-sided silicone-coated PET liners (Rossella, Dolpap, Crosil 42) and seven commercial butyl sealants (C1E, U2E, C1EN, T1E, T2E, T1EN, T2EN) were tested on both liner sides. Two descriptors summarized each force–displacement trace: the mean apparent separation force and an operational slip-stick peak count based on positive residual-force excursions. Most combinations stayed below about 18 cN/25 mm. An increase was observed for T1EN, and a much larger one for Rossella/U2E. In both cases, high, diffuse stress was accompanied by volumetric deformations, fibrillation, and unstable detachment, rather than clean detachment at the phase boundary. Dolpap was the most stable and the most symmetric. Crosil 42 stayed in the low-force range but showed a few material-specific side differences. Taken together, the mean force and the peak count form a reproducible relative screen for selecting actual liner–butyl pairs, one that complements rather than replaces standard release-liner datasheet testing.

The integrity of hollow glass microspheres (HGMs) and the association of (3-aminopropyl)triethoxysilane (APTES) with solvent-resistant organic-phase retention were examined in model butyl sealant compounds based on isobutylene–isoprene rubber (IIR), brominated IIR (BIIR), and polybutene. Within this formulation and mixing system, HGM damage is proposed as a candidate screening indicator of cumulative processing history. HGMs can reduce composite density, but they may be damaged during processing in viscous matrices. Four formulations differing in HGM content, APTES content, and APTES/HGM addition sequence, prepared in two non-randomized batch lineages, were characterized by density, consistency, flow, peel, and tack, and by double toluene extraction coupled with electron microscopy, X-ray microanalysis, infrared spectroscopy, and thermogravimetry. A two-state density balance gave apparent crushed-HGM fractions of 71–89%, depending on the matrix-density reference. A compositionally simplified BIIR/APTES model specimen showed a 65% cyclohexane-insoluble fraction and ¹H diffusion-NMR echo decays consistent with restricted proton mobility. Differences between the two same-composition formulations were associated with broader processing history, including addition sequence. APTES-containing formulations retained a solvent-resistant organic phase after extraction, including on glass surfaces, whereas the APTES-free control retained mainly glass. The specific junction chemistry, including covalent glass–silane anchoring, was not directly resolved. Cold-flow resistance and self-healing were not measured.