• Textile Coloration and Finishing
• /
• v.29 no.2
• /
• pp.55-61
• /
• 2017

A non-fluorinated polystearyl methacrylate water repellent was synthesized by emulsion polymerization. The number and weight averaged molecular weights were obtained at around 137,277 and 237,754g/mole. The melting point was observed at $32^{\circ}C$. The contact angle of water droplet on fabrics treated with the water repellent was $140{\sim}145^{\circ}$ for cotton and polyester, and $125{\sim}130^{\circ}$ for wool and nylon. Since the critical surface tension was estimated at 20.7mN/m, even though relatively not so strong as fluorinated water repellent, it is considered to be used as a good water repellent practically.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.06a
• /
• pp.88-89
• /
• 2020

Research is underway to incorporate water-repellent agents inside mortars to improve the durability of concrete. Therefore, in this study, the mechanical properties and absorption rate were evaluated by adding a hybrid water repellent in which a liquid and a solid were mixed at a constant ratio.As a result of the experiment, the compressive strength of the mortar added with the hybrid water repellent showed a strength reduction of about 5% than the compressive strength of the OPC, and the overall water absorption was lower than that of the water repellent used alone.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.11a
• /
• pp.96-97
• /
• 2020

In this study, the compressive strength and porosity characteristics of cement mortar mixed with liquid and powder composite water repellent were evaluated. When the liquid water repellent was mixed, the compressive strength at 28 days of age was 42% compared to OPC, and the compressive strength was greatly reduced. However, the 28-day compressive strength of the powder water repellent mixture and P5L1, P6L1 liquid and powder composite water repellent was about 97% compared to OPC, and there was little decrease in compressive strength.

• Journal of the Korean Home Economics Association
• /
• v.35 no.3
• /
• pp.115-124
• /
• 1997

In this study, Water Repellent Finish was carried out before dyeing on cotton fabrics. It was aimed to improve on dyeing properties of cotton fabrics with direct dye. The results obtained were summerized as follows: 1. The K/S value of water repellent finished cotton fabrics increased. This phenomena in water repellent finished cotton fabrics were much more noticiable than unfinished cotton fabrics. 2. The color fastness(light, washing, and rubbing) of water repellent finished cotton-dyed were worse than those of unfinished cotton-dyed with direct dye. △E of water repellent finished cotton fabrics wasn't showed significant difference as compared with that of unfinished cotton fabrics. 3. The water repellency of finished cotton after dyeing got down from 100 to 70. That of finished-cotton before dyeing was 100. 4. Moisture regain, stiffness and weight of finished cotton fabrics were not almost differenciated with unfinished cotton fabrics. Moreover, the tensile strength of finished cotton fabrics was increased compared to that of unfinished cotton fabrics. As conclusion, according to the above results when the cotton fabrics were dyed with direct dye, it was much more effective that water repellent finished cotton fabrics were dyed rather than trational process, that is pre-dyeing after-finishing even if, by low liquor ratio. The physical properties of fabrics were maintained or increased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.4
• /
• pp.102-108
• /
• 2015

Agricultural cultivation papers treated with water repellent were investigated in order to analyse mechanical properties and durability. The water repellency was optimal when papers are treated with Wb and Sa water repellents. Also, WCPs with 5% water repellent were more effective than those of 3 and 10%. In addition, water repellency of WCPs with Wb and Sa water repellents were kept constant in correlation with aging time. Finally, WCP with Wb water repellent possesses efficiency in terms of mechanical properties and durability.

• Textile Coloration and Finishing
• /
• v.9 no.4
• /
• pp.1-6
• /
• 1997

Water repellent finish was carried out using water repellent agent(AG-480), melamine resin(Sumitex Resin MK), and catalyst(Sumitex Accelerator ACX). PET/nylon fabrics were treated with melamine resin by pad-dry-cure method and subsequently washed and dried. Durable water repellency was controlled by the melamine resin and catalyst. Water repellency was tested by spray rating method and durability of water repellency were measured by launder-O-meter and pilling tester. The optimum conditions of durable water repellent finish for new synthetic fabric were as follows; concentration of water repellent finishing agent 20g/l; concentration of melamine & catalyst 0.5g/l; curing condition $160^{\circ}$ ${\times}$ 30sec. Water repellency after washing and rubbing is improved by melamine resin and catalyst.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.37 no.2
• /
• pp.182-187
• /
• 2024

Currently, the most developed new energy source is solar energy. Because solar power is installed outside, it is exposed to many pollutants. Pollutants are causing the characteristics of solar energy to deteriorate. Therefore, this study aims to develop a water-repellent coating to prevent contamination of solar modules. Silica and Titania materials are mainly used as water-repellent coating materials. In this study, it was based on silica and the contact angle characteristics were measured according to the change in the amount of silica and ammonia water added and the number of coatings. As a result of the measurement, it was confirmed that the contact angle was more than 60 degrees when 0.5 mol of TEOS was added to 50 mL and 0.15 M when 1 mL of ammonia water was added to 296.47 ml of distilled water. And it was confirmed that the contact angle improved when the number of coatings was applied twice. A water-repellent coating material was applied to low iron tempered glass used to protect dye-sensitized solar cell modules. The characteristics of the module were measured after spraying DI-Water on low-emission tempered glass with a water-repellent coating. As a result of the measurement, the efficiency of the module without application, the efficiency of the module coated once, and the module coated twice were 4.87%, 4.90%, and 4.91%, respectively. It was confirmed that the efficiency of the module increased by applying water-repellent coating. As a result of this study, it is determined that the water-repellent coating material will help improve solar power generation efficiency and lifespan by being self-cleaning and non-reflective.

• Journal of Korean Society for Quality Management
• /
• v.16 no.1
• /
• pp.43-48
• /
• 1988

Most of silicone used for water repellent finish is MHP (methyl hydrodiene polysiloxane), which is formed by hydrolysis and condensation polymerization of MHD (methyl hydrodiene dichlorosilane: Me H Si $Cl_2$). The cross-linking theory explains the water repellent mechanism of MHP. The silicone finish on fiber could improve in handle, softness, abrasion resistance, soil repellency, tear strength and crease resistance, as well as water repellency. According to using method silicone-water repellent finishing agents, could be devided into air dry type and curing type. MHP is the typical curing type of water repellent finishing agent, and this type requires the curing temperature above $150^{\circ}C$ at least. High curing temperature is the very drawback of this curing type. For this reason, there has been global interest in the lowering of its temperature. The objective of this study is to investigate merits of alkali treatment for silicone finishing by ANOVA and LSD (least significant difference).

• Computers and Concrete
• /
• v.34 no.1
• /
• pp.123-135
• /
• 2024

Strain-hardening cement-based composites (SHCC) under cracked condition exhibits remarkable capillary absorption due to water ingress from multiple cracks. Surface treatment using water repellent agents is an effective way for improving water resistance of SHCC, but the water resistance may remarkably decrease when cracks penetrate impregnation depth. Another way is to add water repellent agents directly into the mixture, offering SHCC integral water repellency even if cracks form later. However, although integral water repellent treatment has been proved feasible by previous studies, there is still lack of simulation work on the treated SHCC for evaluating its durability. This study presents a simulation method for capillary absorption of cracked SHCC with integral treatment based on a multi-scale approach proposed in the authors' previous work. The approach deals with water flows in bulk matrix and multiple cracks using two individual transport equations, respectively, whereas water absorbed from a crack to its adjacent matrix is treated as the mass exchange of the two equations. In this study, the approach is enhanced for the treated SHCC by integrating the influencing of water repellency into the two transport equations as well as the mass exchange term. Using the enhanced approach, capillary absorption of water repellent SHCC under cracked condition is simulated, showing much more reduced water ingress than the untreated concrete, which is consistent with total absorption data from previous tests. This approach is also capable of simulating water spatial distribution with time in treated SHCC reasonably.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.1
• /
• pp.289-296
• /
• 2003

The evaluation on performance of gel type penetrative water-repellent for durability progress of concrete structure has carried out in this study. And liquid type waterproof agents have been estimated with same method. Also normal concrete that was not applied water-repellent and waterproof agents have been estimated. As results, the penetrative depth of gel type water-repellent were deeper than that of liquid type waterproof agents and those were superior to these in physical and durable performance.