I. Introduction

As health and well-being have emerged as a global trend, the number of people who enjoy sports and leisure activities has increased. The change in lifestyle as such has brought the ‘athleisure look’, which can satisfy daily life and leisure activities at the same time, into vogue in the world of fashion. In addition, as the time to stay at home has been increasing due to the non-contact culture and telecommuting due to COVID-19, the number of consumers looking for one-mile wear, which is an indoor clothing but can also be worn as an outdoor clothing at places close to the home, and athleisure wear for home training, which is doing exercise at home, has increased. Also, the number of consumers wearing leggings, which are an item becoming popular among clothes with athleisure look, has increased (Han, 2021;Kwon, 2021). Leggings are a modified form of tights and are clothes worn like trousers that cover the waist without the feet part. Tights, which are opaque long socks covering the waist through the feet, appeared in the 1950s and were in vogue in the 1960s together with the trend of miniskirts. In the 1970s, as interest in health increased, elastic materials that had been used only in ski suits and swimwear began to be applied to leggings. In the 1980s, as leisure sportswear were developed due to the increase in leisure time and diverse changes in lifestyles, leggings were worn as fitness and aerobic clothing, and gradually became an item to reveal one’s own individuality while being worn as ordinary clothes. The demand for leggings, which marked its culminating point in the 1980s, began to gradually decrease in the 1990s. However, together with the retro fad in 2006, the leggings of the 1980s reappeared and were spread with new materials and designs and became popular in men’s wear fashion as well (Hwang, 2013). The leggings as such are an item still in vogue because they are practical, inexpensive, and designed diversely. Even in the COVID-19 recession, the domestic leggings market is growing continuously in the fashion clothing market. According to market research firm Euromonitor, the size of the domestic leggings market <Fig. 1> grew from 638.6 billion won in 2016 to 714.2 billion won in 2018 and 762 billion won in 2020, a growth of 2.6% compared to the previous year thereby recording a growing trend only in the clothing category (Yoo, 2021).

The growth of the market and the creation of company’s profits are not only affected by fashion trends and lifestyles, but also by the technological competitiveness of companies. The technological competitiveness possessed by a company has a great effect on the company’s profit creation. The importance of intangible assets such as information, knowledge, and intellectual property rights, as well as tangible assets such as labor and capital, which are the sources of corporate competitiveness, is recognized and active investments are made in intangible assets (Kim, 2011;Korean Intellectual Property Office, 2010). Intellectual property rights are generally classified into industrial property rights, copy rights, and new intellectual property rights. Rights belonging to industrial property rights among them include patents, utility models, trademarks, and designs (Kim, 2011;Kim, 2014).

Patents grant exclusive rights to those who invented new technologies and enable third parties to use disclosed technical information and understand the levels of new technologies and the direction of development. The value of use of patent information as such is high because it is the latest and cutting-edge technology information closely related to industrial development since it can be applied to actual industries (Kim, 2006;Korean Intellectual Property Office, 2021a). A patent is a type of intellectual property that gives a patent owner the legal right to prevent others from making, using, or selling an invention for a limited period of time in exchange for the disclosure of the invention. On the other hand, a utility model is a statutory exclusive right granted by an inventor for a limited period of time in exchange for providing sufficient education for a person with ordinary skills to carry out the invention. Specifically, the utility model is the right to prevent the commercial use of a protected invention by another person without the permission of the right holder for a limited period of time (Findlaw, n.d.). In addition, the exclusive license period for patents is 20 years, longer than that for utility models, which is 10 years. Therefore, in general, it can be seen that utility models are applied for in the case of technical creations with relatively short lifespans or simple technical creations and patents are applied for in the case of high level technical creations (Kim, 2011;Kim, 2014;Shin, 2004). Patents and utility models are classified according to the internationally unified International Patent Classification (IPC) code. The classification system classifies and writes technologies into section, class, sub class, main group, subgroup in order of precedence thereby classifying technologies applied to certain industries in great details (Korean Intellectual Property Office, 2021a).

Design right refers to rights to exclusively implement design creations. The design defined under the Design Protection Act is a product’s shape, form, color, or a combination of them that lead to aesthetic senses through sight (Korean Intellectual Property Office, 2021b). That is, whereas the functions of a product devised are protected by patent rights or utility model rights, parts related to appearance and colors that give aesthetic impressions to the product are protected by design rights (Park & Kim, 2010).

Previous studies on intellectual property rights of fashion apparel products such as a study conducted on patents applied to health-related footwear (Park & Kim, 2012), a study on bra patent technology trends (Jeong, Kwak, & Park, 2020), studies on patents on functional clothing (Jung & Lee, 2014;Kim, 2014;Kim & Park, 2011), a study on patents on men’s underwear (Lee, 2015), a study on patents for cycling wear (Kim & Choi, 2017), a study on patent on posture correction products (Kim & Chun, 2020), a study on the patents and utility model of fashion industry (Kim, 2011) were conducted. In addition, previous studies on leggings conducted on the design, marketing, pattern, production, and consumer perception of leggings such as a study on the formative characteristics of leggings design (Hwang & Choi, 2014), a study on leggings performance improvement (Jung & Kim, 2014), a study on the marketing of leggings products (Lee, Jin, & Shin, 2014), a study on the pattern of leggings for pregnant women (Cha, 2020), a study on the change in the perception of leggings using big data analysis (Han, 2021), and a study on the analysis of leggings production status (Kang, Kang, & Kim, 2021). However, studies on the patents, utility models, and design applications for leggings are insufficient.

Therefore, in this study, patents, utility models, and design application trends for leggings were analyzed in order to understand the technological development trends related to the development of leggings products that are continuously growing in the fashion market. Through the foregoing, this study was intended to identify the development trend of domestic leggings products and present basic data for the development of leggings products hereafter.

II. Method

This study attempted to analyze the trends in patent, utility model, and design applications for domestic leggings. This study analyzed 1) trends of applications for patents and utility models, 2) analysis of patent and utility model applications by subject, 3) trends of design application, 4) analysis design applications by the target of wearing and by item.

The data registered in the Korean Intellectual Property Rights Information Service (KIPRIS, http:// www.kipris.or.kr) provided by the Korea Institute of Patent Information (KIPI) were analyzed in order to identify the trends of applications for domestic leggings, utility models, and designs for tight leggings. Search words such as ‘leggings’ were used to search for the applications of domestic patents, utility models, and designs, and the search range was from 2001 to 2020 based on the filing year.

Data collection and analysis were conducted as follows for analysis by subject and trend of patent and utility model applications. In order to enhance the accuracy of the search for applications for patents and utility models, A41 (wearing apparel clothes) code in the IPC code was added and among the 135 data searched as such, 114 data in the state of disclosure, registration, withdrawal, extinction, and abandonment were retrieved excluding rejected and invalid data. Among the retrieved data, 102 data were finally used in the analysis excluding data not related to leggings. The collected 102 data related to applications for patents or utility models related to leggings patents were classified into application trends by year, present situation of document registration, trends of applications by individuals/companies, trends of applications by South Koreans/foreigners, trends of applications by country, and application items by subject to conduct analyses.

In addition, data collection and analysis were conducted as follows for analysis by design application trend, wear target, and item. In order to enhance the accuracy of search for applications for designs, South Korean classification DC B (clothes and personal items) code was added to the search and among 308 data searched as such, 306 data in the state of disclosure, registration, withdrawal, extinction, and abandonment were retrieved excluding those rejected or invalid. Among the retrieved data, 296 data excluding data not related to leggings were the finally used in the analysis. The 296 collected data related to applications for design were classified into trends of applications by year, present situation of document registration, trends of applications by individuals/companies, trends of applications by South Koreans/foreigners, targets for wearing, and items to conduct analyses.

III. Results and Discussion

1. Trends of applications for patents and utility models

To examine the trends of applications for leggings patents and utility models by year, referring to a previous study (Yoo, Park, & Kim, 2007), the study periods were divided into four sections with a five- year cycle; the first period 2001–2005, the second period 2006–2010, the third period 2011–2015, and the fourth period 2016–2020 in the analysis. The results of analysis of the trends of applications for domestic patents or utility models related to technologies for leggings product development by year are as shown in <Fig. 2>. Only one application was filed in 2001–2005, and as the number of applications gradually increased from 2006, six applications were filed in 2006–2010. In 2011–2015, the applications began to increase rapidly, and 34 applications were filed. Thereafter, the applications continuously increased, and 61 applications were filed in 2016–2020.

Based on the foregoing, the time when leggings were in vogue together with the retro fad in 2006 and the time when applications for leggings-related patents and utility models increased from 2006 seem to be closely related with each other. In addition, the fashion of leggings since 2006 continued in the 2010s too, and as many fashion brands introduced leggings and skinny products of various colors and designs, the sales of leggings increased as essential items for women (Chang, 2011;Kim, 2009). The market trend as such and the trend of applications for leggings-related patents or utility models that rapidly increased from 2011 seem to be closely related with each other.

Referring to previous studies (Jung & Lee, 2014;Lee, 2015;Lee & Han, 2020), the literature status of patents and utility models for leggings, trends in individual/company applications, trends in domestic/ foreign applications, targets and items were classified and analyzed.

The present situations of leggings-related patents and utility model literature was examined and according to the results, the number of patents registered was the largest at 37, followed by those disclosed at 28, those withdrawn at 16, those that became extinct at 12, and those abandoned at 9 <Fig. 3>.

The present situations of leggings-related document registration were examined separately for patents and utility models and according to the results, the proportion of patent applications was significantly higher at 87 cases (85.3%) than that of utility model applications at 15 cases (14.7%). It seems that the number of patent applications is larger because the exclusive right period of patents is longer than that of a utility models. In addition, the characteristics of patent and utility model applicants were analyzed separately for patents and utility models, and for South Koreans and foreigners and the results are as shown in <Fig. 4>. In the case of patents, the number of applications filed by South Koreans was significantly larger at 58 than that of applications filed by foreigners at 29. In the case of utility models, it was found that 15 cases were filed by only South Koreans because no application was filed by foreigners. Regarding domestic leggings, it shows that the share of domestic patent and utility model applications is higher than that of foreigners.

The characteristics of applicants for patents and utility models were analyzed separately for individuals and companies, and South Koreans and foreigners and the results are as shown in <Fig. 5>. The number of patents applied by South Koreans was remarkably larger at 73 (71.6%) that of patents applied by foreigners at 29 (28.4%). The number of patents applied by individuals at 53 (60.0%) was quite similar to that of patents applied by companies at 49 (48.0%). In addition, in the case of patents applied by South Koreans, the number of patents applied by individuals was remarkably larger at 51 (69.9%) than that of patents applied by companies at 22 (30.1%). However, in the case patents applied by foreigners, the number of patents applied by companies was remarkably larger at 27 (93.1%) than that of patents applied by individuals at 2 (6.9%). This seems to have attempted to strengthen the competitiveness of foreign companies in the domestic leggings market through patent applications made at the corporate level rather than individuals.

In addition, the characteristics of applications filed by South Korean and those filed by foreigners by year were examined and the results are as shown in <Fig. 6>. During the period 2001–2005, no application was filed by South Korean and only foreigners filed applications. The proportion of applications filed by South Korean showed a tendency to become higher than that of applications filed by foreigners from 2006 and showed a tendency to become remarkably higher than that of applications filed by foreigners from 2011 to 2020.

The number of patent/utility model applications filed by foreigners is 29 and the result of analysis of the applications by country. As shown in <Fig. 7>, 11 applications were filed by United States, 5 by Japan, 2 by Sri Lanka, 2 by Switzerland, 2 by United Kingdom, 2 by Italy, 2 by France, 1 by Netherlands, 1 by Germany, and 1 by Canada. Among foreign applicants, the proportion of the United States was shown to be remarkably high.

2. Analysis of patent and utility model applications by subject

The 102 leggings-related domestic patent utility model applications filed were analyzed after classifying them with details by subject and the results are as shown in <Table 1>. According to the results, the classified subject that was the most frequently applied was compression shaping functionality at 20 cases (19.6%), followed by construction/sewing at 17 cases (16.7%), accessories and others at 16 cases (15.7%), system/device at 15 cases (14.7%), multi-functionality at 9 cases (8.8%), manufacturing methods at 7 cases (6.8%), construction functionality at 6 cases (5.9%), protection 6 cases (5.9%), and textile/processing at 6 cases (5.9%).

Leggings-related patents and utility models were classified into nine subjects, and representative drawings by subject are presented in <Table 2>. Looking at the details of each subject, in relation to composition/ sewing, patents and utility models related to the structure, shape, design, and sewing method of leggings were mainly proposed. In relation to construction functionality, functional leggings products applied with a function to adjust the length of leggings and construction designs that enhance activity and wearing sensation with a method of manufacturing functional leggings by applying the design of the clothing construction were proposed. In relation to multi-functionality, in addition to general legging functions, leggings that can be used for various functions including underwear-integrated leggings, leggings combined with outerwear, leggings that can be worn inside out too, and leggings that can measure body size were proposed. In relation to the protective function, functional leggings products that prevent injuries that may occur during exercise or daily life and protect the skin were proposed. In relation to accessories and others, accessories of leggings products such as protective pads and innerwear with absorption and deodorization functions were proposed. In relation to the system/ device, string adjustment system, support structures, sensor chips, an antenna reception, and systems and devices with smart functions applied to leggings were proposed. In relation to the compression shaping functionality, functional leggings that compress or reshape the body by applying functional materials and construction designs, etc., and functional leggings products that balance the body and correct the body shape by applying elastic bands and taping methods, etc. were proposed. In relation to manufacturing methods, methods and processes for manufacturing leggings such as fiber manufacturing, fabric, construction designs, and sewing were proposed. In relation to textile/processing, textile technologies such as those for textile yarns, textiles, and processing applied to leggings were proposed.

3. Trends of design application

The period of leggings design application by year was divided into a total of four selections with a fiveyear cycle in the same way as that of the patent and utility model application; the first period 2001–2005, the second period 2006–2010, the third period 2011– 2015, and the fourth period 2016–2020 in the analysis. The results of the analysis are as shown in <Fig. 8>. Looking at the trend of domestic design application related to leggings by year, nothing was filed from 2001 to 2005, and three applications were applied from 2006 to 2010, indicating that the applications gradually began to be filed. However, the application began to increase very rapidly to reach 108 cases in 2011–2015, and then continued to increase to reach 185 cases in 2016–2020. As such, the trend of design applications by year showed a similar trend to the trend of patent/utility model applications. The result of analysis of the trends of leggings design applications as such show that the applications began to increase from 2006 and rapidly increased in the 2010s as with the trends of leggings patent and utility model application years indicating that it is closely related to the trend of the leggings market.

The present situation of leggings-related design application documents was examined and according to the results the number of applications in the state of registration was the largest at 204, followed that in the state of extinction at 85, that in the state of abandonment at 5, and that in the state of disclosure at 2 <Fig. 9>. When comparing with the trend of patent/utility model applications, it was shown that in the case of patent/utility model applications, the number of the state of disclosure was shown to be the largest next to the number of the state of registration but in the case of design applications, the number of the state of the number of the state of extinction was shown to be the largest next to the number of the state of registration.

Looking at the results of analysis of the characteristics of design applicants separately for South Koreans and foreigners, it was found that there were no applications filed by foreigners and only South Koreans filed applications. When compared with the trend of patent/utility model applications, it was found that there were foreigners’ applications for leggings patent/utility model, but there were no foreigners’ applications for leggings design.

In addition, the results of analysis of the characteristics of design applicants separately for individuals and companies are as shown in <Fig. 10>. All the applicants were South Koreans, and the number of individual applicants was shown to be larger at 181 (61.1%) than that of company applicant at 115 (38.9%). As such, in the case of design applications, the trend of applications filed by individuals was shown to be higher among South Korean as with patents and utility model applications.

4. Analysis design applications by the target of wearing and by item

The results of analysis of 296 leggings-related design applications after classifying them by the target of wearing and by the type of leggings are as shown in <Fig. 11>. According to the results, the most frequently filed applications were design applications for general leggings at 206 cases (69.6%), followed by those for item-attached leggings at 52 (17.6%), those for others at 11 cases (3.7%), those for leggings for body shape correction at 10 cases (3.4%), those for leggings for men at 9 cases (3.0%), those for leggings for pregnant women at 5 cases (1.7%), those for leggings for children at 2 cases (0.7%), and an application for leggings for the disabled at 1 case (0.3%). In the results of this study, the number of design applications for pregnant women, children, and the disabled was shown to be very small. This is interpreted to be attributable to the fact that the applications were filed for the maximum number of subjects without limiting the wearer to a specific target.

IV. Conclusion

This study analyzed the trends of applications for leggings-related patents, utility models, and designs filed with the Korean Intellectual Property Office from 2001 to 2020. Through the analysis, this study was intended to identify the quantitative flow and characteristics of technologies and provide basic data that can contribute to the creation of new intellectual properties in related research fields. With regard to patent and utility model applications, analysis was conducted after classifying the applications into trends of applications by year, present situation of document registration, trends of applications filed by individuals/ companies, trends of applications filed by South Koreans/foreigners, trends applications by country, and application items by subject. In addition, with regard to design applications, analysis was conducted after classifying the applications into trends of applications by year, present situation of document registration, trends of applications by individuals/companies, trends of applications by South Koreans/foreigners, targets for wearing, and items to conduct analyses.

The study results are as follows. First, the trends of applications for patents, utility models, and designs by year were analyzed and according to the results, the trends by year of patent/utility model and design applications were almost the same. It began to increase from 2006 and increased rapidly in the 2010s. This suggests that the trends are closely related to the trend of the leggings market, which has been in fashion continuously since 2006.

Second, the trends of applications for patents and utility models were analyzed and according to the results, the proportion of patent applications was higher than that of utility models and individuals rather than companies filed applications more frequently in the case of South Koreans while companies rather than individuals filed applications more frequently in the case of foreigners. In the case of utility models, there were no foreign applications. In addition, in the case of design applications, it was found that there were no foreign applications and only South Koreans filed applications. Among applications filed by South Koreans, the number of applications filed by individuals was larger than that of applications filed by companies.

Third, the patent and utility model applications were analyzed by subject and according to the results, the number of applications for compression shaping functionality was the largest followed by construction/ sewing, accessories and others, system/device, and multi-functionality, in order of precedence. Looking at the details by subject, the details include construction/ sewing regarding structures, shapes, designs, and sewing methods, construction functionality regarding functional leggings products applied with clothing construction designs, multi-functionality regarding products added with various functions utilized, protection functions regarding functional leggings products that prevent injuries and protect the skin, accessories and others of leggings, systems and devices applied to leggings, compression shaping functionality to compress or correct the body, leggings manufacturing methods such as fiber manufacturing, fabrics, construction design, and sewing, and textile/processing applied to leggings.

Fourth, design applications were classified by the target for wearing and by the type of leggings and according to the results, design applications for general leggings were filed the most frequently, followed by those for item-attached leggings, those for others, those for leggings for body shape correction, those for leggings for men, those for leggings for pregnant women, those for leggings for children, and those for leggings for the disabled, in order of precedence.

As shown in the results of this research, many applications for patents and utility models for various functions related to leggings were filed, but not much technology was developed for textile/processing. However, since leggings are important products with stretchability and body shape correction functions, it is expected that technologies related to new materials and processing should be actively developed in the future to improve the functionality of leggings products. Patent, utility model, and design applications for the development of leggings products using smart technology are still insignificant, so it is expected that if healthcare leggings products with smart sensors and functions are developed in the future, they will be able to enter the blue ocean market. In addition, as the trend of athleisure looks that can create styles while enabling enjoying daily life and leisure at the same time continues, the leggings product market is very highly likely to continuously grow. Accordingly, as shown by the findings indicating that applications for patents, utility models, and designs related to leggings have continuously increased since 2006, it seems the number of applications related to leggings will continue to increase hereafter too. Recently, leggings have been worn not only for indoor exercise such as yoga and pilates, but also for hiking among young people, indicating that sales of outdoor leggings have increased rapidly. Leggings are also expanding to wear by middle-aged women and men, leading the growth of the sportswear market. As such, the leggings market is an industry with great consumption potential along with the increase in various customers. For the continuous growth of industries in related fields, it is necessary to develop trendy and comfortable products using new materials and fiber manufacturing technologies as well as the functionality of leggings as shown in the research results. Therefore, it is considered that attempts to develop various product technologies should be continuously made for the continuous growth of the leggings industry hereafter.

Although this study may have limitations in that it is limited to domestic patents, utility models, and design applications, it is meaningful in that it collected information related to leggings products and presented directions for future development. In future studies, based on this study, we intend to analyze overseas application trends and present data to find strategic methods for overseas expansion.