• Journal of the Korean Applied Science and Technology
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• v.15 no.2
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• pp.59-66
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• 1998

Two-packaged polyurethane coatings were prepared by blending benzoic acid lactone modified polyester polyol(BLMPs) and HDI-biuret. BLMPs were synthesized by polycondensation of benzoic acid, viscosity depression component, with 1,4-butanediol, adipic acid, and polycaprolactone polyol. Kinematic viscosity of BLMP was gradually decreased with increasing benzoic acid content in BLMP. The low viscosity of modified polyester has an advantage of making a high-solid content coatings. After the film was coated with the prepared polyurethane coatings and cured at room temperature, the various physical properties were measured. They showed good physical properties such as flexibility, impact resistance, cross hatch adhesion, yellowness index, and rust resistance. These advantages are the results of introducing polycaprolactone polyol.

• Polymer(Korea)
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• v.24 no.1
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• pp.72-81
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• 2000

Benzoic acid polyester/lactone polyol were synthesized by polycaprolactone 0201 as diol, trimethylolpropane as triol, adipic acid as dibasic acid, and benzoic acid as monobasic acid. Polyisocyanate prepolymer Desmodur N-100 of HDI-biuret type was used in this study. Two-component polyurethane coatings were prepared by blending benzoic acid polyester/polycaprolactone, polyisocyanate, wetting/dispersing agent, white pigment, and flowing agent. Various properties were examined on the film coated with the prepared polyurethane. They showed excellent physical properties such as abrasion resistance, accelerated weathering resistance, and yellowness index. They also showed good physical properties such as flexibility, impact resistance, 60$^{\circ}$ specular gloss, cross hatch adhesion, hydrocarbon resistance, and lightness index difference. Hardness of coating showed a little poor character. The introduction of polycaprolactone 0201 as diol in the polyurethane coatings improved the hydrocarbon resistance, impact resistance, and flexibility of coatings. According to the drying and curing behavior with the contents of benzoic acid, they seem to have reasonable coating properties such as drying time of 2 to 4 hours and pot-life time of 20 to 37 hours.

• Polymer(Korea)
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• v.30 no.3
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• pp.238-246
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• 2006

The aim of this study is to enhance the flame retardancy by the synergism effect of chlorine and phosphorus groups. The flame-retardant polyurethane coatings containing chlorine and phosphorus compounds were synthesized. After synthesizing the intermediate products of tetramethylene bis (orthophosphate) (TMBO) and neohexanediol trichlorobenzoate (TBA-adduct), the condensation polymerization was performed with four different monomers of two intermediates, 1,4-butanediol, and adipic acid to obtain four-component copolymer(TTBA). The two-component flame-retardant polyurethane coatings (TTBA-10C/HDI-trimer=TTHD-10C, TTBA-20C/HDI-trimer=TTHD-20C, TTBA-30C/HDI trimer=TTHD-30C) were obtained by curing reaction at room temperature with the synthesized TTBAs and hexamethylene diisocyanate (HDI)-trimer as a curing agent. The obtained TTHDs were made into coating samples and used as test samples for various physical properties. The physical properties of the flame-retardant coatings containing chlorine and phosphorus groups were generally inferior to those containing only phosphorus group. Flame retardancy was tested by vortical and horizontal combustion method, and $45^{\circ}$ Meckel burner method. Since the retardancy of flame-retardant coatings containing chlorine and phosphorus groups was better than that containing only phosphorus group, it could be concluded that the retardancy by the synergism effect of chlorine and phosphorus groups exhibited.

• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.211-216
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• 2017

The dielectric properties of two polyurethanes (PUs) with different hard segments, i.e., aromatic methylene di-p-phenyl diisocyanate (MDI) and aliphatic hexamethylene diisocyanate (HDI), were investigated in the temperature range of -100 to $100^{\circ}C$ and in the frequency range of 1 Hz to 3 kHz. The ${\alpha}$-relaxations induced by the glass transition of the equivalent soft segments in the two PUs occurred at relaxation times of ${\tau}=3.46{\times}10^{-3}s$ for MDI-PU and ${\tau}=3.39{\times}10^{-2}s$ for HDI-PU at $-20^{\circ}C$, in accord with the temperature-frequency superposition principle, resulting in similar shifting factors. However, different I-relaxations were observed for the two PUs. The I-relaxation of MDI-PU occurred due to the mobility of the chain extenders near $80^{\circ}C$ with a slower shifting rate than the ${\alpha}$-relaxation. On the other hand, I-relaxation arising from both the extender and the unconstrained hard segments of HDI-PU occurred at $70{\sim}100^{\circ}C$, indicating complicated dielectric behavior due to partial interaction with the ${\alpha}$-relaxation at high frequencies. Thus, the I-relaxation of HDI-PU did not follow the superposition principle. The dielectric behaviors of the PUs were mainly influenced by their phase transitions, which were affected by the structure and components of the materials.

• 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.10 no.2
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• pp.37-44
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• 1998

In this study, the polyurethane microcapsules containing disperse dye were prepared by in-situ polymerization method using hexamethylene diisocyanate (HDI, aliphatic type) and m-xylene diisocyanate(XDI, aromatic type) with ethylene glycol (EG) And the size, shape, particle size distribution, and breaking behavior of microcapsules prepared were investigated. The size and shape of microcapsule were observed by scanning electron microscope (SEM) . The particle size distribution was analyzed by image analyzer. The breaking behavior of microcapsule was checked by measuring the optical density of solution that the disperse dye was dissolved after the microcapsule was broken by constant pressure. The particle size was inversely proportional to the stirring speed, and the size of microcapsule prepared from HDI and EG was smaller than that of microcapsule prepared from XDI and EG. Aliphatic type microcapsule was broken easily, compared with aromatic type one. It was considered due to the difference of reactivity between HDI and XDI. And the microcapsule prepared by stirring strongly was broken easily.

• Elastomers and Composites
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• v.58 no.3
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• pp.121-127
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• 2023

The effect of diisocyanate type on the decomposition temperature of polyurethane (PU) hydrolysis was investigated in a subcritical water medium up to 250℃. PU samples were prepared using different types of diisocyanate: two aromatic diisocyanates (4,4'-methylene diphenyl diisocyanate (MDI) and methyl phenylene diisocyanate (TDI)), one unbranched aliphatic diisocyanate (hexamethylene diisocyanate (HDI)), and two cyclic aliphatic diisocyanates (4,4'-methylene dicyclohexyl diisocyanate (H₁₂MDI) and isophorone diisocyanate (IPDI)). The pressure had no effect on hydrolysis in the range of 70-250 bar. The decomposition temperature of the PU samples increased in the following order: TDI-PU (199℃) < H₁₂MDI ≈ IPDI ≈ HDI (218-220℃) < MDI-PU (237℃). This order of increase in temperature is related to the electron-donating ability of the group to connected to the nitrogen of the urethane unit. When the temperature of the (PU + water) mixture reached the specific decomposition temperature, the PU samples hydrolyzed completely within 5 min into primary amine and 1,4-butanediol. The hydrolysis products from MDI-PU and H₁₂MDI-PU were separated into a liquid phase rich in (BD + water) and a solid low phase rich in amine, whereas the products from TDI-, IPDI-, and HDI-PU existed in a single aqueous phase.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.39-44
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• 2005

In this study, polyurethane-acryl emulsion resins were synthesized from HDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate), Polyol, 2-HEMA (2-hydroxy ethylmethacrylate), n-BA (n-butyl acrylate) and MMA (methylmethacrylate). The effects of polyol types on the properties of polyurethane-acryl emulsion resin, such as degree of strength and water resistance and on the manufacturing process were investigated. In addition, the results were compared with those of acrylic emulsion. The test results showed that polyester type polyol demonstrated stronger tensile strength and higher water resistance with time than did acrylic emulsion and polyether type polyol.

• Elastomers and Composites
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• v.54 no.1
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• pp.30-34
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• 2019

Four different diisocyanates (IPDI; isophorone diisocyanate, HDI; hexamethylene diisocyanate, HMDI; dicyclohexylmethane-4,4'-diisocyanate, and XDI; m-xylylene diisocyanate) were used to prepare polyurethane gel-coats, and the weatherabilities, physical properties, and surface characteristics of the gel-coats were investigated with respect to the chemical structure of the diisocyanates. The weathering test results indicated that all of the diisocyanates used in this study were suitable for use in the preparation of the polyurethane gel-coat. However, the set-to-touch times and physical properties of the polyurethane gel-coat indicated that the cycloaliphatic diisocyanate (IPDI and HMDI) were ideal for the preparation of polyurethane gel-coats.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.77-84
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• 2006

Modified polyesters (TTBA-10C, -20C, -30C) that contain phosphorus and chlorine were synthesized by the condensation polymerization of tetramethylene bis(orthophosphate), neohexanediol trichlorobenzoate, 1,4-butanediol and adipic acid, in which tetramethylene bis(orthophosphate) and neohexanediol trichlorobenzoate were prepared previously in our laboratory. In this study, two-component flame-retardant polyurethane coatings (TTBA-10C/HDI-trimer=TTHD-10C, TTBA-20C/ HDI-trimer= TTHD-20C, TTBA-30C/HDI-trimer= TTHD-30C) were obtained by curing at room temperature with the synthesized TTBAs and hexamethylene diisocyanate (HDI)-trimer as a curing agent. The obtained TTHDs were made into coating samples and used as test samples for various physical properties. The physical properties of the flame-retardant coatings containing chlorine and phosphorus groups were generally inferior to those containing only phosphorus group. Flame retardancy was tested by vertical and horizontal combustion method, and $45_{\circ}$ Meckel burner method. Since the retardancy of flame-retardant coatings containing chlorine and phosphorus groups was better than that containing only phosphorus group, it could be concluded that the retardancy by the synergism effect of chlorine and phosphorus groups exhibited.