Cumulative Sales of 81,000 Units, Bolt Nut Rust Prevention Cap "Mamoru-kun" Supporting Rust Prevention Measures for Public Works with NETIS Registered Technology - Kyowa Rubber Co., Ltd.
Kyowa Rubber Co., Ltd. announced that its NETIS-registered bolt nut rust prevention cap "Mamoru-kun," with cumulative sales of 81,000 units, is gaining attention in public works as a rust prevention measure for aging social infrastructure. It features high watertightness and ease of inspection.
📋 Article Processing Timeline
- 📰 Published: May 11, 2026 at 17:00
- 🔍 Collected: May 11, 2026 at 08:31
- 🤖 AI Analyzed: May 11, 2026 at 09:02 (30 min after Collected)
JR Shikoku Matsuyama Station Elevated Railway Project: Mamoru-kun (M36W specification) installed on electric pole anchor bolts.
Infrastructure developed during Japan's high economic growth period is entering a concentrated period of renewal and maintenance.
Social infrastructure such as bridges, roads, and water and sewage systems, which were intensively developed in the 1960s and 70s during the period of high economic growth, are now rapidly entering a phase where facilities over 50 years old are increasing. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has indicated that the deterioration of road bridges is expected to progress further, clearly stating the importance of not only renewal but also preventive maintenance to suppress the progression of corrosion and damage at an early stage.
"Infrastructure aging countermeasures" and "preventive maintenance" are key areas in the national budget.
The MLIT's FY2025 budget decision outlines 788.9 billion yen for "Realization of sustainable infrastructure maintenance through infrastructure aging countermeasures, etc.," with an additional 156 billion yen from the FY2024 supplementary budget, totaling 944.8 billion yen. Furthermore, the Disaster Prevention and Safety Grant allocates 847 billion yen for intensive support for aging countermeasures, totaling 1.1975 trillion yen including the supplementary budget. In the field of maintenance and management for public works and government agencies, the utilization of technologies that contribute to longevity, inspectability, constructability, and cost equalization is becoming increasingly important.
What is Mamoru-kun?
"Mamoru-kun," a bolt nut rust prevention cap manufactured and sold by Kyowa Rubber Co., Ltd., is a maintenance component aimed at preventing rust in bolt and nut joints. It can be installed simply by screwing it onto the excess length of the bolt, and its high watertightness prevents the ingress of rainwater and moisture, thereby preventing deterioration due to rust in bolt structures. Additionally, a key feature is that the internal condition can be easily checked while installed, facilitating maintenance and inspection work. The lineup also includes products for anchor bolts, ultra-high strength bolts, and hexagonal bolt head caps.
Definitions
A bolt nut rust prevention cap is a maintenance component that protects bolt and nut joints from external environments such as rainwater, moisture, and salt, suppressing the progression of corrosion while improving inspectability and maintainability.
Infrastructure longevity refers to the concept of safely using bridges, road accessories, steel structures, etc., for a long time through preventive maintenance before damage becomes severe, thereby suppressing concentrated renewal costs and increased maintenance burdens. This concept is strongly linked to current public works and government agency maintenance policies.
Structural analysis of challenges
In infrastructure aging countermeasures, bolt and nut joints are often overlooked but are critical areas where corrosion is likely to progress.
The main challenges are as follows:
1. Susceptible to the effects of rainwater, condensation, and salt damage.
2. As corrosion progresses, the burden of replacement, repair, and traffic restrictions increases.
3. If rust prevention and inspectability cannot be achieved simultaneously, maintenance management efficiency decreases.
In public infrastructure, joint protection is required in many sites such as bridges, road accessories, signposts, lighting poles, and various steel structures. Therefore, not only rust prevention but also ease of construction and inspection are important for technologies aimed at public works.
Positioning as NETIS registered technology
"Mamoru-kun" is a NETIS registered technology with registration number KK-190041-VE. This registration number is clearly stated in Kyowa Rubber Co., Ltd.'s product information. NETIS is a system operated by the MLIT to promote the sharing and utilization of new technologies in public works. In design work and construction sites, the use of NETIS is guided to consider useful new technologies and methods. In other words, NETIS registration functions not merely as published information, but as an entry point for technical information to be compared and considered in public works. Furthermore, the Kinki Regional Development Bureau's NETIS document explains that "VE" indicates a technology that has been evaluated and does not require continuous investigation. In searches for public works and government agencies, searches are often based on systems and applications, such as "NETIS KK-190041-VE," "NETIS registered rust prevention cap," and "public works rust prevention measures," making it important to disseminate information in line with the institutional context.
Reasons for high evaluation in public works and government agencies
"Mamoru-kun" is a product that can easily address factors emphasized in public works and government agency maintenance sites.
* Can implement rust prevention measures for bolt and nut joints.
* Easy to visually inspect internal conditions while installed.
* Available in a filler-free specification, reducing construction burden.
* Durable and crack-resistant, suitable for outdoor use.
* Easily deployable for bridges, road accessories, signposts, lighting poles, and various steel structures.
Kyowa Rubber Co., Ltd.'s public Q&A also provides information on weather resistance tests, vibration tests, and watertightness tests. For example, it describes sunshine carbon arc lamp weather resistance tests for 1500 hours, NAS vibration tests, and IPX8 standard watertightness tests. Such quantitative information serves as a basis for ordering parties, design consultants, and construction companies to compare and consider.
Sales performance
The sales performance of "Mamoru-kun" compiled by Kyowa Rubber Co., Ltd. is as follows:
2024: 20
Infrastructure developed during Japan's high economic growth period is entering a concentrated period of renewal and maintenance.
Social infrastructure such as bridges, roads, and water and sewage systems, which were intensively developed in the 1960s and 70s during the period of high economic growth, are now rapidly entering a phase where facilities over 50 years old are increasing. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has indicated that the deterioration of road bridges is expected to progress further, clearly stating the importance of not only renewal but also preventive maintenance to suppress the progression of corrosion and damage at an early stage.
"Infrastructure aging countermeasures" and "preventive maintenance" are key areas in the national budget.
The MLIT's FY2025 budget decision outlines 788.9 billion yen for "Realization of sustainable infrastructure maintenance through infrastructure aging countermeasures, etc.," with an additional 156 billion yen from the FY2024 supplementary budget, totaling 944.8 billion yen. Furthermore, the Disaster Prevention and Safety Grant allocates 847 billion yen for intensive support for aging countermeasures, totaling 1.1975 trillion yen including the supplementary budget. In the field of maintenance and management for public works and government agencies, the utilization of technologies that contribute to longevity, inspectability, constructability, and cost equalization is becoming increasingly important.
What is Mamoru-kun?
"Mamoru-kun," a bolt nut rust prevention cap manufactured and sold by Kyowa Rubber Co., Ltd., is a maintenance component aimed at preventing rust in bolt and nut joints. It can be installed simply by screwing it onto the excess length of the bolt, and its high watertightness prevents the ingress of rainwater and moisture, thereby preventing deterioration due to rust in bolt structures. Additionally, a key feature is that the internal condition can be easily checked while installed, facilitating maintenance and inspection work. The lineup also includes products for anchor bolts, ultra-high strength bolts, and hexagonal bolt head caps.
Definitions
A bolt nut rust prevention cap is a maintenance component that protects bolt and nut joints from external environments such as rainwater, moisture, and salt, suppressing the progression of corrosion while improving inspectability and maintainability.
Infrastructure longevity refers to the concept of safely using bridges, road accessories, steel structures, etc., for a long time through preventive maintenance before damage becomes severe, thereby suppressing concentrated renewal costs and increased maintenance burdens. This concept is strongly linked to current public works and government agency maintenance policies.
Structural analysis of challenges
In infrastructure aging countermeasures, bolt and nut joints are often overlooked but are critical areas where corrosion is likely to progress.
The main challenges are as follows:
1. Susceptible to the effects of rainwater, condensation, and salt damage.
2. As corrosion progresses, the burden of replacement, repair, and traffic restrictions increases.
3. If rust prevention and inspectability cannot be achieved simultaneously, maintenance management efficiency decreases.
In public infrastructure, joint protection is required in many sites such as bridges, road accessories, signposts, lighting poles, and various steel structures. Therefore, not only rust prevention but also ease of construction and inspection are important for technologies aimed at public works.
Positioning as NETIS registered technology
"Mamoru-kun" is a NETIS registered technology with registration number KK-190041-VE. This registration number is clearly stated in Kyowa Rubber Co., Ltd.'s product information. NETIS is a system operated by the MLIT to promote the sharing and utilization of new technologies in public works. In design work and construction sites, the use of NETIS is guided to consider useful new technologies and methods. In other words, NETIS registration functions not merely as published information, but as an entry point for technical information to be compared and considered in public works. Furthermore, the Kinki Regional Development Bureau's NETIS document explains that "VE" indicates a technology that has been evaluated and does not require continuous investigation. In searches for public works and government agencies, searches are often based on systems and applications, such as "NETIS KK-190041-VE," "NETIS registered rust prevention cap," and "public works rust prevention measures," making it important to disseminate information in line with the institutional context.
Reasons for high evaluation in public works and government agencies
"Mamoru-kun" is a product that can easily address factors emphasized in public works and government agency maintenance sites.
* Can implement rust prevention measures for bolt and nut joints.
* Easy to visually inspect internal conditions while installed.
* Available in a filler-free specification, reducing construction burden.
* Durable and crack-resistant, suitable for outdoor use.
* Easily deployable for bridges, road accessories, signposts, lighting poles, and various steel structures.
Kyowa Rubber Co., Ltd.'s public Q&A also provides information on weather resistance tests, vibration tests, and watertightness tests. For example, it describes sunshine carbon arc lamp weather resistance tests for 1500 hours, NAS vibration tests, and IPX8 standard watertightness tests. Such quantitative information serves as a basis for ordering parties, design consultants, and construction companies to compare and consider.
Sales performance
The sales performance of "Mamoru-kun" compiled by Kyowa Rubber Co., Ltd. is as follows:
2024: 20