Even after 2000 rubs, it won't scratch! The "Second Sponge," a cleaning item that "removes without scraping," proves its overwhelming power in harsh damage evaluation tests by public institutions.
Kino Sozai Co., Ltd.'s "Second Sponge" has demonstrated in rigorous tests by public institutions that it does not scratch materials even after 2000 rubs. This new coil fiber technology enables "removing dirt without scraping," a feat difficult for existing cleaning products, ensuring safe cleaning for cookware and delicate materials.
📋 Article Processing Timeline
- 📰 Published: April 27, 2026 at 21:50
- 🔍 Collected: April 27, 2026 at 13:31
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Kino Sozai Co., Ltd. (Headquarters: Kochi City, Kochi Prefecture, Representative Director: Takehisa Okamura) conducted "Sponge Damage Evaluation Tests" with the Kochi Prefectural Paper Industry Technology Center for its newly developed sponge, the "Second Sponge."
As a result, it was officially demonstrated that the material was not scratched at all, even under the extremely harsh conditions of rubbing back and forth up to 2000 times with a load of 1kgf.
■ Test Result Summary: Zero scratches after 2000 rubs
The test was conducted under very strict conditions, applying a 1kgf load to commercially available plastic plates (made of polystyrene, confirmed to be scratch-free beforehand) and moving a water-soaked sponge back and forth. Afterward, the surface was observed for scratches using a scanning electron microscope (SEM).
"Melamine sponges," "abrasive sponges," "urethane sponges," and "cotton gauze cloths" were simultaneously tested as comparisons.
【Verification Result 1】Clear difference in 1000 rub test
After rubbing 1000 times with common sponges and cloths, the following differences were confirmed:
Reciprocating abrasion testing machine
* Abrasive sponge / Melamine sponge: Significant linear scratches were observed on the plastic plate surface.
* Cotton gauze cloth: Although it is a soft material, the rubbing force was directly transmitted, causing fine scratches.
* Second Sponge / Urethane Sponge: Almost no change from before the test; no scratches were observed.
Electron microscope images after 1000 rubs
【Verification Result 2】Strength proven in extreme "2000 rub" test
For the urethane sponge and Second Sponge, which showed no scratches, an extreme test of "2000 rubs" – double the previous – was conducted.
Urethane sponge: Linear scratches appeared on the surface.
Second Sponge: Even after rubbing 2000 times, no scratches were observed at all.
Electron microscope images after 2000 rubs
* Supplement regarding test results
Melamine sponges and abrasive sponges are cleaning products that remove dirt by "polishing (scraping)." The occurrence of scratches in this test is due to the product's characteristics and can be considered proof of its high effectiveness.
For cloths and urethane sponges, scratches occurred under extremely harsh, non-typical usage conditions. Since their usage scenarios and purposes differ, this test does not evaluate the superiority or inferiority of the products.
As its name suggests, the Second Sponge is recommended for use in conjunction with these other products.
■ Safe cleaning possible with "Second Sponge"
The results of these official institutional tests have firmly supported the "Second Sponge's" characteristic of "removing dirt while not damaging materials" with reliable data.
You can use it safely for cookware you don't want to scratch and for general cleaning.
Colored stains, sinks, washbasins, root vegetables, pet dishes, camping
【Examples of applicable items】 Can be used on easily scratched materials such as enamel, plastic, stainless steel, iron plates, aluminum, ceramics, artificial marble, acrylic tanks, and coated materials like fluororesin processing, anti-fog glass/mirrors, and root vegetables (Food Sanitation Act compliant).
Baking molds can also be easily washed.
Bakery ovens became clean with just water.
■ Second Sponge Technology (Coil Fiber)
Regarding fiber structure:
Electron microscope images show that the "Second Sponge" has a special structure where very fine fibers are coiled and entangled, unlike general sponges.
Fine fibers absorb a lot of dirt. Pointed parts are less likely to emerge, making the shape less prone to scratching surfaces. Spring-like elasticity absorbs and disperses impact. This technology has created the effect of removing dirt well without scratching.
More detailed information, such as comparisons of dirt removal effectiveness, is available on our website, please check it.
Homepage: https://kinousozai.co.jp/secondsponge.html
■ Trial product now on sale for ¥1! (Shipping not included)
* A trial product (5 sheets) is currently on sale for ¥1 (shipping not included) at our Rakuten shop.
* The regular 14-sheet product is also available.
→Link to Kino Sozai official shop (Rakuten)
You can purchase after confirming performance beforehand.
■ Sales will begin at many other shops.
Sales have started at some home centers, supermarkets, and drugstores.
It is also available online at Rakuten, Amazon, Yodobashi Camera, etc.
Updates are posted regularly on Kino Sozai's official Instagram page.
→Link to Kino Sozai Instagram page
■ "Second Sponge" Product Overview
Material: PET, PE
Size (per sheet): 120mm (H) x 50mm (W) x 5mm (T)
Contents: 14 sheets
Country of origin: Japan (Food Sanitation Act compliant)
Award: Grand Prize, 67th Osaka International Gift Show "New Product Contest"
As a result, it was officially demonstrated that the material was not scratched at all, even under the extremely harsh conditions of rubbing back and forth up to 2000 times with a load of 1kgf.
■ Test Result Summary: Zero scratches after 2000 rubs
The test was conducted under very strict conditions, applying a 1kgf load to commercially available plastic plates (made of polystyrene, confirmed to be scratch-free beforehand) and moving a water-soaked sponge back and forth. Afterward, the surface was observed for scratches using a scanning electron microscope (SEM).
"Melamine sponges," "abrasive sponges," "urethane sponges," and "cotton gauze cloths" were simultaneously tested as comparisons.
【Verification Result 1】Clear difference in 1000 rub test
After rubbing 1000 times with common sponges and cloths, the following differences were confirmed:
Reciprocating abrasion testing machine
* Abrasive sponge / Melamine sponge: Significant linear scratches were observed on the plastic plate surface.
* Cotton gauze cloth: Although it is a soft material, the rubbing force was directly transmitted, causing fine scratches.
* Second Sponge / Urethane Sponge: Almost no change from before the test; no scratches were observed.
Electron microscope images after 1000 rubs
【Verification Result 2】Strength proven in extreme "2000 rub" test
For the urethane sponge and Second Sponge, which showed no scratches, an extreme test of "2000 rubs" – double the previous – was conducted.
Urethane sponge: Linear scratches appeared on the surface.
Second Sponge: Even after rubbing 2000 times, no scratches were observed at all.
Electron microscope images after 2000 rubs
* Supplement regarding test results
Melamine sponges and abrasive sponges are cleaning products that remove dirt by "polishing (scraping)." The occurrence of scratches in this test is due to the product's characteristics and can be considered proof of its high effectiveness.
For cloths and urethane sponges, scratches occurred under extremely harsh, non-typical usage conditions. Since their usage scenarios and purposes differ, this test does not evaluate the superiority or inferiority of the products.
As its name suggests, the Second Sponge is recommended for use in conjunction with these other products.
■ Safe cleaning possible with "Second Sponge"
The results of these official institutional tests have firmly supported the "Second Sponge's" characteristic of "removing dirt while not damaging materials" with reliable data.
You can use it safely for cookware you don't want to scratch and for general cleaning.
Colored stains, sinks, washbasins, root vegetables, pet dishes, camping
【Examples of applicable items】 Can be used on easily scratched materials such as enamel, plastic, stainless steel, iron plates, aluminum, ceramics, artificial marble, acrylic tanks, and coated materials like fluororesin processing, anti-fog glass/mirrors, and root vegetables (Food Sanitation Act compliant).
Baking molds can also be easily washed.
Bakery ovens became clean with just water.
■ Second Sponge Technology (Coil Fiber)
Regarding fiber structure:
Electron microscope images show that the "Second Sponge" has a special structure where very fine fibers are coiled and entangled, unlike general sponges.
Fine fibers absorb a lot of dirt. Pointed parts are less likely to emerge, making the shape less prone to scratching surfaces. Spring-like elasticity absorbs and disperses impact. This technology has created the effect of removing dirt well without scratching.
More detailed information, such as comparisons of dirt removal effectiveness, is available on our website, please check it.
Homepage: https://kinousozai.co.jp/secondsponge.html
■ Trial product now on sale for ¥1! (Shipping not included)
* A trial product (5 sheets) is currently on sale for ¥1 (shipping not included) at our Rakuten shop.
* The regular 14-sheet product is also available.
→Link to Kino Sozai official shop (Rakuten)
You can purchase after confirming performance beforehand.
■ Sales will begin at many other shops.
Sales have started at some home centers, supermarkets, and drugstores.
It is also available online at Rakuten, Amazon, Yodobashi Camera, etc.
Updates are posted regularly on Kino Sozai's official Instagram page.
→Link to Kino Sozai Instagram page
■ "Second Sponge" Product Overview
Material: PET, PE
Size (per sheet): 120mm (H) x 50mm (W) x 5mm (T)
Contents: 14 sheets
Country of origin: Japan (Food Sanitation Act compliant)
Award: Grand Prize, 67th Osaka International Gift Show "New Product Contest"