By [email protected] — Charting the depths of expertise
Woven cleanroom wipes (excluding nonwovens) are constructed from yarns, each composed of tens to hundreds of fine filaments (continuous polyester or polyester/nylon composite fibers). Based on the fineness of a single filament, these wipes are categorized as standard (polyester) fiber, sub-microfiber, or microfiber. Fiber fineness directly impacts key performance aspects like cleaning power, absorbency, abrasion resistance, chemical resistance, and sealed-edge cleanliness.
The table below clarifies the meaning of key terms in the context of cleanroom wipes.
| Term | Definition | Description |
|---|---|---|
| Yarn | The basic unit of a woven cleanroom wipe. | A cleanroom wipe is woven from many yarns. |
| Filament | The basic unit of a yarn; refers to a single continuous fiber. | A single yarn is composed of dozens to hundreds of filaments. |
| Continuous Filament Fiber | An unbroken, single filament of polyester or polyester/nylon composite. | Structurally stable with a low risk of breaking or shedding. |
| Staple Fiber | Short, discontinuous fibers. | Spun into yarn; no concept of filaments. Prone to breaking and shedding, thus typically not used for cleanroom wipes. |
Fiber Fineness Unit (dtex) & Cleanroom Wipe Classifications
1. dtex (Decitex) - The Core Unit of Fiber Fineness
dtex (decitex) is a unit of linear density that expresses fiber fineness. It is defined as the weight in grams per 10,000 meters of fiber. For example, a fiber weighing 11 grams per 10,000 meters has a linear density of 11 dtex. A lower dtex value means a finer, softer fiber, though its strength may be reduced.
The dtex value helps determine if a fiber is a microfiber. While standards vary by country, the Japanese standard is a common reference for cleanroom wipes.
2. Cleanroom Wipe Classification by Fiber Fineness
Based on dtex, cleanroom wipes are classified as standard, sub-microfiber, or microfiber. The standards and performance differences are detailed below:
| Performance Parameter | Standard Fiber Cleanroom Wipe | Sub-Microfiber Cleanroom Wipe | Microfiber Cleanroom Wipe | Ultra-fine Microfiber Cleanroom Wipe |
|---|---|---|---|---|
| Fiber Fineness | Coarsest | Medium | Fine | Ultra-fine |
| Single Filament Fineness | >1.5 dtex | 0.55-1.5 dtex | 0.11-0.55 dtex | <0.11 dtex |
| Material | 100% Polyester | 100% Polyester | Commonly 80% Polyester + 20% Nylon | Special process Poly/Nylon composite |
| Cleaning Ability | General | Better | Strong | Excellent |
| Absorbency / Adsorption | General | Better | Strong | Excellent |
| Scratch Risk | High | Medium | Low | Very Low |
| Particle Generation/Shedding | High | Medium | Low | Very Low |
| Production Cost | Low | Medium | High | Very High |
| Typical Application | General industrial cleaning | Touch screens, LCD cleaning | Semiconductors, optical instruments | High-end optics, aerospace equipment |
Common Industry Specs: Denier and Filament Count (F-Number)
1. Denier - The Core Unit of Yarn Fineness
In practice, cleanroom wipes are typically specified by their yarn count, such as "50D72F," rather than their direct dtex value:
50D: "D" is for Denier, a unit of yarn fineness. 50D means 9,000 meters of the yarn weigh 50 grams. A smaller number indicates a finer yarn. 50D is considered a medium-fineness yarn for cleanroom wipes.
72F: "F" is for Filament, the number of single filaments in a yarn. 72F means the yarn consists of 72 filaments. A higher filament count results in a softer yarn. For example, a 72F yarn is softer than a 36F yarn (because its filaments are finer).
2. Conversion between Denier and dtex
Using "50D72F" as an example:
Total Denier → Total dtex: 50D x (10/9) ≈ 55.56 dtex Single Filament Fineness: 55.56 dtex / 72F ≈ 0.77 dtex
Based on the classification table, since 0.55 dtex < 0.77 dtex < 1.5 dtex, 50D72F is classified as a sub-microfiber.
If the spec were 50D144F, the calculated fineness would be 0.39 dtex, classifying it as a microfiber cleanroom wipe.
Common Denier counts in the cleanroom wipe industry are 50 and 75 (90D is rare), with common Filament counts of 36, 72, and 144.
How Fiber Fineness Affects Cleanroom Wipe Performance
Finer fibers improve the following properties:
Enhanced Cleaning Power: Tightly packed fibers increase surface area, enhancing Van der Waals forces for stronger particle capture. Increased Absorbency: Finer fibers create a larger surface area (and typically a higher basis weight), which increases liquid absorption. Improved Abrasion Resistance and Tensile Strength: The tight fiber packing minimizes filament displacement under stress, reducing the likelihood of wear or breakage. Better Chemical Resistance: The dense fiber arrangement forms a physical barrier, slowing the penetration of chemical agents. Cleaner Sealed Edges: On a denser fabric, a laser-sealed edge is less likely to fray or shed particles. Higher Cost, Lower Breathability, and potentially reduced softness if too dense.
How to Choose: Standard, Sub-Microfiber, or Microfiber Cleanroom Wipes?
The core principle is to choose based on need and balance the cost. Ask yourself three questions: 1. Where will it be used? 2. What will it wipe? 3. What is the budget?
Define Your Application Environment & Cleanliness Class: For general cleaning in ISO 7-8 environments, cost-effective standard or sub-microfiber cleanroom wipes are sufficient. For critical ISO 3-5 areas in semiconductor, high-end optics, or biopharmaceutical manufacturing, you must choose microfiber cleanroom wipes to prevent microscopic contaminants from causing costly product defects. Assess the Wiped Surface's Sensitivity and Value: For delicate, high-value surfaces like coated optics or precision instruments, the superior softness of microfiber cleanroom wipes is key to preventing scratches. For non-sensitive surfaces like equipment housing, this extra cost is unnecessary. Balance Performance and Cost: The goal is to avoid the contamination risk of "underperformance" while preventing the cost waste of "over-performance." For example, a sub-microfiber wipe may suffice for LCD panel production; upgrading to a more expensive microfiber wipe is an unnecessary investment if it doesn't significantly improve yield.
If you remain unsure, contact a PICOWIPE sales representative for a tailored recommendation. PICOWIPE produces over 500 types of standard, sub-microfiber, and microfiber cleanroom wipes.
In conclusion, selecting the right cleanroom wipe is a systematic process. Understanding your process's true cleanliness requirements is essential for making the most cost-effective and technically sound choice.
