Preference and subjective evaluation of washed fabric hand using conjoint analysis
Hyo-Seon Ryu1 and Eui Kyung Roh2
The hand of washed fabrics can be changed by varying the laundry detergent ingredients and the properties of washing liquid. The ingredients brought by changes to the hand of fabrics can be considered by subjective assessment. Three types of cotton fabrics were washed in a drum-type washer with 16 different laundry detergents, which are based on profiles derived from a fractional factorial design. A questionnaire method was used to evaluate fabrics washed by 16 different detergent combinations. Zeolite was the most important ingredient for the preference of the washed fabrics in a dry state, followed by hardness, pH, LA-7, LAS, and soap. Each ingredient affected the subjective hands in a different way.
Surfactants such as LA-7 and LAS, zeolite and soap affected the subjective hand more, while pH and hardness affected the subjective hand less. An increase in the surface-friction related slippery feeling and the fullness/softness resulted in an increase in the preference for the hand of the washed fabric.
Conjoint analysis, detergent, drum-type washer, preference, subjective hand, washed fabric
The market share of drum-type washers is increasing in
Korea, resulting in consumers being more concerned about the rinsing effect of this type of washer because the amount of water used is about one fifth of that of a pulsator or agitator washer. Visual sensation, smell, and touch are usually involved in the assessment of the subjective rinsing effect of washed cloth.
In general, fabrics, especially cotton fabrics, are very stiff after washing because fiber and weave are fixed and do not move freely. The surfactant sticking on the fiber is not easily removed through rinsing, except for silk, and a lot of surfactant adheres to the fiber after rinsing.1 It was found that the presence of zeolite in the detergent changed the subjective hand of washed fabrics in a wet state and zeolite had a greater effect than other detergent ingredients on preference.2 Therefore the hand of washed fabrics can be changed by varying the detergent ingredients and the conditions brought by the changes on the hand of fabrics can be considered by subjective assessment.
The hand of fabrics is a very important factor when consumers select fabric. There have been many trials that evaluated and predicted the hands of fabrics.
Knowing how to change the hand and the preference of washed fabrics and to affect the hand of washed fabric are a necessity, and developers of laundry detergent may make predictions about consumer responses to particular types of detergent. There is a lot of research about fabric hand before washing using objective evaluation,3–4 subjective evaluation,5–10 correlation between the objective and the subjective evaluation,11–16 and the hand change according to the finish condition.17–18
Some researchers have investigated the effect on the changes of physical properties of the washed fabric.
The preceding research 2 showed the effect of detergent on the preference of washed fabrics in a wet state, using 1Seoul National University, Gwanak-gu, Seoul, Republic of Korea. 2Yonsei University, Seodaemun-gu, Seoul, Republic of Korea.
Eui Kyung Roh, Yonsei University, 134 Shinchon-dong, Seodaemun-gu,
Seoul, 120-749, Republic of Korea
Textile Research Journal 80(20) 2167–2175 ! The Author(s) 2010
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DOI: 10.1177/0040517510376270 trj.sagepub.com at Scott Memorial Library @ Thomas Jefferson University on March 10, 2015trj.sagepub.comDownloaded from multiple regression with dummy variables and MDS (Multi-Dimensional Scaling). However, there are few studies about the preference and the subjective evaluation change of washed fabrics according to detergent ingredients.
Conjoint analysis provides a quantitative measure of the relative importance of one attribute (ingredient) compared to another. Conjoint analysis has been used when alternative products have a number of attributes, each with two or more levels, and when most of the feasible combinations of the attribute levels do not presently exist.19 Research on knit fabrics20 and highperformance fabrics for mountaineering jackets21 applied conjoint analysis to measure the utilities of various fabric attributes. The use of conjoint analysis is appropriate in measuring how much consumer satisfaction changes based on the level of ingredients relative to another change. Knowing preferences of detergents containing various ingredients is most important to understanding consumers’ needs.
The purposes of this research are to assess the effect of the detergent ingredients and the properties of the washing liquid on the preference and the subjective hand of the washed fabrics in a dry state, to analyze the relationship between the preference and the subjective hand, and to identify the combination of ingredients that best meet consumers’ needs.
Three types of cotton fabric; cotton plain weave (C100) and cotton/polyester blend plain weave fabric (C+P) for dress shirt, and cotton knit fabric (Knit) for t-shirt, as shown in Table 1, were used and the cotton-type fabrics were laundered in a drum-type washer.
The ingredients and their amount were determined based on the composition of detergents on the market (Table 2) and the remainder of the detergent composition was sodium sulfate (Na2SO4). pH was controlled by sodium carbonate (Na2CO3) and hardness was controlled by a combination of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3).
The massive number of ingredient combinations is too large for respondents to rate in a meaningful way. The full-concept approach in MINITAB 14 used fractional factorial designs, which uses a smaller fraction of all possible alternatives. This reduced size subset (orthogonal array) considers only the main effect and the interactions are assumed to be negligible.