• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.461-469
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• 2010

Polyurethane adhesive is used in various fields as flexible packaging materials including a food packaging field. Therefore, the purpose of this study is synthesis of polyurethane adhesive which uses aliphatic isocyanate, and compares with aromatic isocyanate. The isocyanates for this test are toluene-2,4-diisocyanate(TDI), hexamethylene diisocyanate(HDI), 4,4-dicyclohexyl ethane diisocyanate($H_{12}MDI$), and isophorone diisocyanate(IPDI). And, the effect of any other diisocyanate are evaluated by several methods as for curing rate test, accelerate weathering test, and peel strength test. The polyurethane adhesive using curing catalyst and HDI has adhesion strength of about 560 g/15 mm between aluminium foil and nylon, about 1,520 g/15 mm between nylon and CPP. Those parameters are similar to polyurethane adhesive with TDI. Also, in case of curing rate, those are similar to TDI type polyurethane adhesive. Moreover, data of ${\Delta}E$ as color variation by QUV tester is equal to 4.12, as 48% against those of TDI type.

• Textile Coloration and Finishing
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• v.30 no.2
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• pp.90-97
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• 2018

Hydrophilic reactive hot-melt polyurethane adhesive(HRHA) using a hydrophilic polyol having different molecular weight and NCO index was synthesized. This HRHA was synthesized using Polyethylene glycol(PEG) as a hydrophilic polyol, Polypropylene glycol(PPG) and Polycaprolactone diol(PCL) as hydrophobic polyols, and Methylene diphenyl diisocyanate(MDI) as an isocyanate. The changes in IR spectrum, viscosity and thermal properties of HRHA with different PEG molecular weights and NCO index were investigated, and the tensile strength and elongation of the HRHA casting film and the peel strength, moisture permeability and water pressure of the HRHA coated fabric were confirmed. In this experiment, as the molecular weight of PEG and NCO index increased, the adhesive strength, tensile strength, elongation and moisture permeability was increased but viscosity and Tg was decreased.

• Journal of Adhesion and Interface
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• v.11 no.1
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• pp.26-34
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• 2010

We synthesized polyurethane adhesive having thermal characteristic could be debonded by heat treatment and made a dismantlable polyurethane adhesive including thermally expansive bead. We used dynamic mechanical thermal analyzer (DMA) to confirm thermal characteristic and investigated bond strength, dismantlement property of dismantlable polyurethane adhesive by content of thermally expansive bead, heating trigger and treatment conditions. The dismantlable polyurethane adhesive could be expanded by hot-air or microwave treatment and the dismantlement of the specimens became easier as the weight fraction of the thermally expansive bead increased. At the dismantlable polyurethane adhesive, the content of thermally expansive bead 40% was suitable for both bond strength and dismantlement, in case of using hot-air treatment as trigger for dismantlement, bonded joints were separated easily at $160^{\circ}C$ for 30 min and in case of using microwave as trigger, bonded joints were separated easily by irradiating microwave for 4 min.

• Composites Research
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• v.22 no.2
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• pp.14-17
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• 2009

Adhesive joints are widely used for structural joining applications in various fields and environmental conditions. Polyurethane adhesive is using for LNG carrier with cryogenic temperature condition. In industrial application of polyurethane adhesive, void of adhesive layer is often discussed regarding its effects on bonding properties. In present study, artificial void were prepared on Polyurethane adhesive layer with various size and location. The single lap shear test was carried out by using prepared specimens under $-170^{\circ}C$. As a result, it was confirm that the void of adhesive layer didn't affect the adhesion properties independent of their size and location.

• Journal of the Korean Wood Science and Technology
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• v.50 no.3
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• pp.167-178
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• 2022

To investigate the influence of manufacturing environment on bonding performance of mixed cross laminated wood (CLT) using polyurethane (PUR) adhesive, a boiling water soak delamination test according to the temperature and relative humidity was conducted. The 5-ply mixed CLT consisted of Japanese Larch for external and middle layer and yellow poplar for internal layer. The PUR adhesives with different opening times of 10 and 30 minutes were used. The mixed CLT was manufactured according to pressing times of PUR and manufacturing environments of summer and winter. In case of summer environment, the delamination rate of the mixed CLT with pressing time of 4 hours using a PUR adhesive with open time of 10 minutes met the requirements of KS F 2081. In case of winter environment, the delamination rate of the mixed CLT didn't meet the requirements of KS standard. However, it was possible to confirm the effect of improving the adhesive performance by adjusting the pressing time according to the open time of the adhesive under the manufacturing conditions. The delamination rate of CLT with open time 30 minutes PUR, manufactured by indirect moisture supply methods was 11.2% better than direct moisture supply methods. As a result of delamination test in the same condition of relative humidity and adhesive, it was found that the temperature of manufacturing environment influences the adhesive performance.

• Composites Research
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• v.22 no.4
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• pp.13-19
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• 2009

Adhesive joints are widely used for structural joining applications in various fields and environmental conditions. Polyurethane adhesive is using for LNG carrier with cryogenic temperature condition. Even if similar polyurethane adhesive is used for different substrate, it shows different adhesion properties. Specially, variation of adhesion properties depending on the resin system or fiber is very important factor for selection of adhesive on industrial application. In present study, we got different peel strength according to the different test temperature when different polyurethane adhesive was used for same fiber reinforced composite. The main cause was investigated using by SEM and it was proven that the different adhesion property between glass fiber on composite surface and polyurethane adhesives at cryogenic temperature.

• Journal of Adhesion and Interface
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• v.19 no.4
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• pp.167-172
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• 2018

In this study, a polyurethane hot melt adhesive was synthesized and metal particles sensitive to induction heating were added to produce an induction heating melt adhesive. The thermal behavior and adhesion characteristics of metal particles were investigated according to the kind, size and induction heating conditions. Among the various metal particles, induction heating efficiency was the best when nickel and iron were applied. Induction heating efficiency increased with decreasing metal particle size. In addition, the strength of the induction heating power of the adhesive was high and the adhesive strength was improved as the adhesive thickness was thinner.

• Macromolecular Research
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• v.14 no.6
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• pp.634-639
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• 2006

Waterborne polyurethane (WBPU) adhesive with varying amounts of dimethylol propionic acid (DMPA) was synthesized by prepolymer process and blended with polyisocyanate hardener. The mean particle size of the WBPU dispersion decreased with increasing DMPA content. $^1H$ NMR spectroscopy confirmed the formation of allophanate bonds and biuret bonds due to the reaction of hardener NCO with urethane/urea groups. The optimum NCO content with the greatest adhesive strength was dependent on the total content of urethane/urea groups in the WBPU molecules. The optimum NCO content increased with increasing number of urethane groups (DMPA content). The adhesion strength of WBPU adhesives was maximized at a molar ratio of hardener NCO to urethane/urea of about 0.28.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.527-530
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• 2007

The binary liquid type fire retardant paint of polyurethane (alkyd resin) lacquer is developed to cover the defect of one liquid type white paint of chlorinated rubber used generally but which has weak surface and poor adhesive strength to the wood as well as generating much black smoke when it is firing. The properties of the composition of binary liquid type of white paint of polyurethane lacquer developed in this study for using to wood has shown that the better suppressed smoke generation and enhanced the adhesive strength to the wood than that of fire retardant white paint used.

• Polymer(Korea)
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• v.36 no.2
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• pp.119-123
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• 2012

Adhesion strength of polyurethane adhesive for laminated metal plate was investigated. Also, the effect of laminating conditions on the adhesion strength was understood by measuring peel strength as a function of adhesion temperature and time. The amount of isocyanate appearing due to the unblocking of oxime in polyurethane adhesive affected the strength of adhesion with hydroxyl on the metal plate or aluminum foil and it was controlled by adhesion temperature and time. However, the excess of temperature and time in laminating process caused the lowering of adhesion strength because of the decrease of solvent content as well as thermal degradation of the adhesive.