scholarly journals Influence of Acrylic Acid on Kinetics of UV-Induced Cotelomerization Process and Properties of Obtained Pressure-Sensitive Adhesives

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5661
Author(s):  
Agnieszka Kowalczyk ◽  
Mateusz Weisbrodt ◽  
Beata Schmidt ◽  
Konrad Gziut
Keyword(s):  
Acrylic Acid ◽  
Crosslinking Agent ◽  
Solid Content ◽  
Scanning Calorimetry ◽  
Adhesive Properties ◽  
Pressure Sensitive Adhesives ◽  
Molecular Weights ◽  
Pressure Sensitive ◽  
Physicochemical Features ◽  
Kinetics Of

A new environmentally friendly method of photoreactive pressure-sensitive adhesives (PSAs) preparation was demonstrated. PSAs based on n-butyl acrylate (BA), acrylic acid (AA) and 4-acryloyloxy benxophenone (ABP) were prepared via the UV-induced cotelomerization process in the presence of a radical photoinitiator (acylphosphine oxide) and telogen (tetrabromomethane). Hydroxyterminated polybutadiene was used as a crosslinking agent. Influence of AA concentration (0–10 wt %) on kinetics of the cotelomerization process was investigated using a photodifferential scanning calorimetry method, selected physicochemical features of obtained photoreactive BA/AA/ABP cotelomers (molecular masses, polydispersity, monomers conversion and dynamic viscosity) and self-adhesive properties of obtained PSAs (adhesion, tack and cohesion) were studied, as well. It turned out that AA content is the important factor that influences monomers conversion (thereby the volatile parts content in prepolymer) and PSAs’ properties. As the acrylic acid content increases, the reaction rate increases, but the total monomers conversion and the solid content of the prepolymer decreases. Additionally, the adhesion and cohesion of PSAs were grown up, and their tackiness decreased. However, the AA content has no effect on molecular weights (Mw and Mn) and polydispersity (c.a. 1.5) of photoreactive cotelomers. The optimal AA content necessary to obtain a prepolymer with low volatile parts content and good PSA properties was determined.

scholarly journals The Effect of Type-I Photoinitiators on the Kinetics of the UV-Induced Cotelomerization Process of Acrylate Monomers and Properties of Obtained Pressure-Sensitive Adhesives

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4563
Author(s):  
Agnieszka Kowalczyk ◽  
Mateusz Weisbrodt ◽  
Beata Schmidt ◽  
Agata Kraśkiewicz
Keyword(s):  
Reaction Rate ◽  
Solid Content ◽  
Type I ◽  
Pressure Sensitive Adhesives ◽  
Molecular Weights ◽  
Pressure Sensitive ◽  
Acrylic Monomers ◽  
Solids Content ◽  
Acrylate Monomers ◽  
Kinetics Of

A new method of solvent-free acrylic pressure-sensitive adhesives (PSAs) based on UV-induced cotelomerization products was presented. The key acrylic monomers (i.e., n-butyl acrylate and acrylic acid) with copolymerizable photoinitiator 4-acrylooxybenzophenone in the presence of a selected chain transfer agent (tetrabromomethane, TBM) were used in the UV-cotelomerization process. Moreover, two kinds of UV-photoinitiators (α-hydroxyalkylphenones, HPs and acylphosphine oxides, APOs) were tested. Photo-DSC, viscosity, thermogravimetric, and GPC measurements for cotelomers were performed. The kinetics study revealed that the systems with APOs, especially Omnirad 819 and Omnirad TPO, were characterized by a much higher reaction rate and greater initiation efficiency than HPs systems were. Additionally, the APO-based syrups exhibited a higher solid content (ca. 60–96 wt%), a higher dynamic viscosity (5–185 Pa·s), but slightly lower molecular weights (Mn and Mw) compared to HP syrups. However, better self-adhesive features (i.e., adhesion and tack) were observed for PSAs based on cotelomers syrups obtained using APOs with lower solid contents (55–80 wt%). It was found that as the solids content (i.e., monomers conversion) increased the adhesion, the tack and glass transition temperature decreased and the type and amount of photoinitiator had no effect on polydispersity. Most of the obtained PSAs were characterized by excellent cohesion, both at 20 °C and 70 °C.

Curing Properties of UV-Cured Pressure Sensitive Adhesives

2013 ◽  
Vol 812 ◽  
pp. 131-137 ◽  
Author(s):  
Jamarosliza Jamaluddin ◽  
Myung Cheon Lee
Keyword(s):  
Differential Scanning Calorimetry ◽  
Relative Concentration ◽  
Crosslinking Agent ◽  
Total Reflection ◽  
Scanning Calorimetry ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Gel Fraction ◽  
Atr Spectroscopy ◽  
Fraction Determination

In this study the effect of trimethylopropane triacrylate (TMPTA) content as a crosslinking agent on curing properties of UV-cured pressure sensitive adhesives (PSAs) was investigated. The curing properties were studied using gel fraction determination, photo-differential scanning calorimetry (photo-DSC) and Fourier transform infraredattenuated total reflection (FTIR-ATR) spectroscopy. Gel fraction sharply increased after expose to UV irradiation and increased with increasing TMPTA content. Moreover, the addition of TMPTA as crosslinking agent induced an earlier onset of auto acceleration and relative concentration of the C=C was not zero because they were trapped in the PSAs network.

scholarly journals Influence of Acrylic Acid and Tert-Dodecyl Mercaptan in the Adhesive Performance of Water-Based Acrylic Pressure-Sensitive Adhesives

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2879
Author(s):  
Irene Márquez ◽  
Núria Paredes ◽  
Felipe Alarcia ◽  
José Ignacio Velasco
Keyword(s):  
Acrylic Acid ◽  
Chain Transfer ◽  
Shear Resistance ◽  
Chain Transfer Agent ◽  
Adhesive Properties ◽  
Gel Content ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Water Based ◽  
Dodecyl Mercaptan

Currently, pressure-sensitive adhesives (PSA) are used in more than 80% of all labels in the market today. They do not require any heat, solvent, or water to activate: It only takes light pressure to apply them to a product surface. Many products that come in glass bottles need labels that have staying power in harsh conditions. For that reason, it is necessary to have a good balance between all the polymer adhesive properties. In this study is described how adhesive properties of water-based PSA were affected by varying the amount of functional monomer acrylic acid (AA) and chain transfer agent, tert-dodecyl mercaptan (TDM). Four series of PSA were prepared by emulsion polymerization. Within each polymer series, the AA monomer proportion was held constant between 0.5 and 3.0 phm, and the fraction of the chain transfer agent was varied 0.0 to 0.2 phm. The results showed that the gel content decreased with the increase of the chain transfer agent and with the reduction of AA. All adhesives properties (tack, peel, and shear resistance) improved with increasement of the AA monomer. The increase of chain transfer agent caused decrease of the gel content resulting in higher peel resistance and tack values, but lower shear resistance values.

scholarly journals Adhesive Performance of Acrylic Pressure-Sensitive Adhesives from Different Preparation Processes

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2627
Author(s):  
Irene Márquez ◽  
Núria Paredes ◽  
Felipe Alarcia ◽  
José Ignacio Velasco
Keyword(s):  
Average Particle Size ◽  
Gel Permeation Chromatography ◽  
Shear Resistance ◽  
Deformation Energy ◽  
Average Particle ◽  
Scanning Calorimetry ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Monomeric Composition ◽  
Adhesive Performance

A series of pressure-sensitive adhesives (PSAs) was prepared using a constant monomeric composition and different preparation processes to investigate the best combination to obtain the best balance between peel resistance, tack, and shear resistance. The monomeric composition was a 1:1 combination of two different water-based acrylic polymers—one with a high shear resistance (A) and the other with a high peel resistance and tack (B). Two different strategies were applied to prepare the adhesives: physical blending of polymers A and B and in situ emulsion polymerization of A + B, either in one or two steps; in this last case, by polymerizing A or B first. To characterize the polymer, the average particle size and viscosity were analyzed. The glass transition temperature (Tg) was determined by differential scanning calorimetry (DSC). The tetrahydrofuran (THF) insoluble polymer fraction was used to calculate the gel content, and the soluble part was used to determine the average sol molecular weight by means of gel permeation chromatography (GPC). The adhesive performance was assessed by measuring tack as well as peel and shear resistance. The mechanical properties were obtained by calculating the shear modulus and determination of maximum stress and the deformation energy. Moreover, an adhesive performance index (API) was designed to determine which samples are closest to the requirements demanded by the self-adhesive label market.

scholarly journals Structural and Viscoelastic Properties of Thermoplastic Polyurethanes Containing Mixed Soft Segments with Potential Application as Pressure Sensitive Adhesives

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3097
Author(s):  
Mónica Fuensanta ◽  
José Miguel Martín-Martínez
Keyword(s):  
Phase Separation ◽  
Potential Application ◽  
Viscoelastic Properties ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Adhesion Properties ◽  
Pressure Sensitive Adhesives ◽  
Thermoplastic Polyurethanes ◽  
Pressure Sensitive ◽  
Soft Segments

Thermoplastic polyurethanes (TPUs) were synthetized with blends of poly(propylene glycol) (PPG) and poly(1,4-butylene adipate) (PAd) polyols, diphenylmethane-4,4′-diisocyanate (MDI) and 1,4-butanediol (BD) chain extender; different NCO/OH ratios were used. The structure and viscoelastic properties of the TPUs were assessed by infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, thermal gravimetric analysis and plate-plate rheology, and their pressure sensitive adhesion properties were assessed by probe tack and 180° peel tests. The incompatibility of the PPG and PAd soft segments and the segregation of the hard and soft segments determined the phase separation and the viscoelastic properties of the TPUs. On the other hand, the increase of the NCO/OH ratio improved the miscibility of the PPG and PAd soft segments and decreased the extent of phase separation. The temperatures of the cool crystallization and melting were lower and their enthalpies were higher in the TPU made with NCO/OH ratio of 1.20. The moduli of the TPUs increased by increasing the NCO/OH ratio, and the tack was higher by decreasing the NCO/OH ratio. In general, a good agreement between the predicted and experimental tack and 180° peel strength values was obtained, and the TPUs synthesized with PPG+PAd soft segments had potential application as pressure sensitive adhesives (PSAs).

scholarly journals Balanced Viscoelastic Properties of Pressure Sensitive Adhesives Made with Thermoplastic Polyurethanes Blends

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1608 ◽  
Author(s):  
Fuensanta ◽  
Vallino-Moyano ◽  
Martín-Martínez
Keyword(s):  
Phase Separation ◽  
Viscoelastic Properties ◽  
Simple Procedure ◽  
Peel Strength ◽  
Similar Degree ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Pressure Sensitive Adhesives ◽  
Thermoplastic Polyurethanes ◽  
Pressure Sensitive

Pressure sensitive adhesives made with blends of thermoplastic polyurethanes (TPUs PSAs) with satisfactory tack, cohesion, and adhesion have been developed. A simple procedure consisting of the physical blending of methyl ethyl ketone (MEK) solutions of two thermoplastic polyurethanes (TPUs) with very different properties—TPU1 and TPU2—was used, and two different blending procedures have been employed. The TPUs were characterized by infra-red spectroscopy in attenuated total reflectance mode (ATR-IR spectroscopy), differential scanning calorimetry, thermal gravimetric analysis, and plate-plate rheology (temperature and frequency sweeps). The TPUs PSAs were characterized by tack measurement, creep test, and the 180° peel test at 25 °C. The procedure for preparing the blends of the TPUs determined differently their viscoelastic properties, and the properties of the TPUs PSAs as well, the blending of separate MEK solutions of the two TPUs imparted higher tack and 180° peel strength than the blending of the two TPUs in MEK. TPU1 + TPU2 blends showed somewhat similar contributions of the free and hydrogen-bonded urethane groups and they had an almost similar degree of phase separation, irrespective of the composition of the blend. Two main thermal decompositions at 308–317 °C due to the urethane hard domains and another at 363–373 °C due to the soft domains could be distinguished in the TPU1 + TPU2 blends, the weight loss of the hard domains increased and the one of the soft domains decreased by increasing the amount of TPU2 in the blends. The storage moduli of the TPU1 + TPU2 blends were similar for temperatures lower than 20 °C and the moduli at the cross over of the moduli were lower than in the parent TPUs. The improved properties of the TPU1 + TPU2 blends derived from the creation of a higher number of hydrogen bonds upon removal of the MEK solvent, which lead to a lower degree of phase separation between the soft and the hard domains than in the parent TPUs. As a consequence, the properties of the TPU1 + TPU2 PSAs were improved because good tack, high 180° peel strength, and sufficient cohesion were obtained, particularly in 70 wt% TPU1 + 30 wt% TPU2 PSA.

REACTION KINETICS OF HEXAMETHYLENE DIISOCYANATE AND POLYPROPYLENE GLYCOLS

2014 ◽  
Vol 87 (4) ◽  
pp. 617-628
Author(s):  
Min-Tzung Ye ◽  
Shinn-Gwo Hong
Keyword(s):  
Reaction Kinetics ◽  
Frequency Factor ◽  
Mechanical Analysis ◽  
Hexamethylene Diisocyanate ◽  
Empirical Equations ◽  
Ozawa Method ◽  
Scanning Calorimetry ◽  
Isothermal Reaction ◽  
Molecular Weights ◽  
Kinetics Of

ABSTRACT The kinetics of the reaction between hexamethylene diisocyanate (HDI) and polypropylene glycols (PPG) of different molecular weights toward the synthesis of polyurethanes with versatile properties was studied using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). From the dynamic exotherms observed in DSC, it was found that the Kissinger equation modified by an additional temperature term in its frequency factor term was able to accurately describe the isothermal reaction kinetics of all HDI/PPG reactions. The modification can be justified by analyses with the Ozawa method and the modulus observed under DMA measurements. Regardless of the type of PPG used, the frequency factors changed with respect to the degree of conversion and maximized at near 70% conversion. The derivation of the modified kinetic equation is presented. In addition, the empirical equations describing the dependence of the activation energies and frequency factors on the molecular weights of PPG were also derived.

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