PCB board separator sulfur-free paper

Industrial Paper for PCB Circuit Board Manufacturing

In the full PCB production workflow, beyond the core sulfur-free paper, the following specialized industrial papers are classified across five key process stages: process manufacturing, surface treatment, lamination & encapsulation, cleaning & wiping, and packaging & transportation.

I. Process Manufacturing (Core Production)

1. PCB Sulfuric Acid Paper (Alias: PCB Tracing Paper) Semi-transparent and heat-resistant, used for circuit design transfer printing and photoresist matching. Commonly used in DIY and small-batch prototype production, ensuring micron-level circuit reproduction without deformation or carbonization under high-temperature transfer.
2. PCB Heat Transfer Paper Available as yellow matte heat transfer paper and PnP blue paper (polyester substrate). Circuit diagrams are laser-printed in mirror image and heat-transferred onto copper-clad boards to form etch-resistant patterns, replacing traditional photolithography. Suitable for small-batch production.
3. PCB Interlayer Paper (Aliases: Circuit Board Separator Paper, Circuit Board Pad Paper) Protects OSP coatings and immersion silver/gold surfaces. Used for stacking isolation to prevent scratching and oxidation. Low sulfur content (some are sulfur-free formulas), compatible with immersion silver, gold-plated, and other high-precision PCBs.
4. Copper-Clad Laminate Base Paper High-performance wood pulp paper that can be impregnated with phenolic resin to produce build-up circuit boards, or combined with epoxy resin and glass cloth as a substitute for fiberglass boards. Features high wet strength, no breakage during resin impregnation, and excellent permeability.

II. Surface Treatment (Electroplating / Etching / OSP)

1. PCB Immersion Silver Process Pad Paper Sulfur-free and chlorine-free, preventing chemical reactions between sulfur and silver that cause yellowing. Used for inter-board isolation and protection during immersion silver board production.
2. PCB Immersion Gold Anti-Oxidation Separator Paper Sulfur-free and dust-free, preventing oxidation and scratching of gold-plated layers. Compatible with immersion gold boards and gold finger boards during processing and storage. (Note: Immersion gold and immersion silver processes use sulfur-free paper.)
3. OSP Protection Paper Specially coated and compatible with OSP coatings without reaction. Prevents OSP board surfaces from absorbing moisture and contamination, maintaining coating stability.
4. Anti-Etching Paper (Anti-Rust Category) Heat-resistant and chemically corrosion-resistant, used to mask non-etching areas during manual etching as a dry film substitute. Suitable for simple circuit board production.

III. Lamination & Encapsulation (Multilayer Board Production)

1. PCB Release Paper (Alias: Demolding Paper) Silicone-coated, used during multilayer board lamination to separate prepreg (PP sheets) from press boards, preventing adhesion and ensuring clean demolding after lamination with no adhesive residue.
2. Prepreg Isolation Paper Heat-resistant above 200°C, used to isolate prepreg during storage and cutting, keeping the adhesive film surface clean to ensure lamination adhesion and insulation performance.
3. PCB Insulation Paper (Aliases: Nomex Paper, Kapton Paper) High-temperature resistant with high dielectric strength, used for internal PCB insulation, heat dissipation, and cushioning. Compatible with power boards, industrial control boards, and other high-voltage circuit boards.
4. PCB High-Temperature Resistant Lining Paper Withstands temperatures above 250°C, used for positioning and protecting PCBs during lamination, preventing surface impressions and contamination. Leaves no marks after lamination.

IV. Cleaning & Wiping (Cleanroom Environment)

1. PCB Dust-Free Paper (Aliases: Stencil Wiping Paper, Auto Wiping Paper) Composed of 55% wood pulp and 45% polyester fiber. Extremely low particle generation (≤Class 10), fast liquid absorption. Used for SMT stencil cleaning, PCB surface dust and adhesive removal, and post-plating cleaning. Compatible with Class 100 to Class 1000 cleanroom environments.
2. PCB Anti-Static Dust-Free Paper Surface electrostatic resistance of 10⁷–10⁹Ω, compliant with ANSI/ESD S20.20 standard. Eliminates static buildup and prevents dust adsorption. Used for cleaning high-precision PCBs and electronic components.
3. PCB Absorbent Paper (Alias: Oil-Absorbent Paper) High water absorbency with no fiber shedding. Used for post-wash water absorption on PCBs and plating solution adsorption, preventing water stains from affecting product quality.

V. Packaging & Transportation (Finished Product Protection)

1. PCB Anti-Static Paper Special conductive coating for rapid static discharge. Surface resistivity of 10⁶–10¹¹Ω, preventing electrostatic breakdown of PCB chips and components. Used for finished PCB packaging and transportation.
2. PCB Moisture-Proof Paper (Alias: Moisture-Proof Composite Paper) Polyethylene-coated or aluminum foil composite. Blocks moisture vapor (moisture transmission rate ≤5g/m²·24h), preventing PCB moisture absorption, oxidation, and solder joint corrosion. Suitable for long-distance sea freight and storage in humid regions.
3. PCB Anti-Rust Paper Coated with vapor-phase rust inhibitor. Used for packaging PCB assemblies containing metal components, preventing rust on copper, iron, and other metal parts. Compatible with military-grade and automotive electronics PCBs.
4. PCB Halogen-Free Paper Contains no halogens (chlorine and bromine ≤900ppm), compliant with RoHS and REACH standards. Used for high-end electronic device PCB packaging, preventing toxic gas generation during combustion.
5. PCB Packaging Kraft Paper 45–80g, high strength and tear-resistant. Used for inner lining and overall wrapping of PCB outer cartons, providing cushioning and shock protection. Some formulas are sulfur-free and halogen-free, meeting environmental requirements.

Comparison: Core Products vs. Sulfur-Free Paper

Key Specifications Summary

• Common Grammages: 25g, 30g, 35g, 40g (lightweight isolation); 45g, 60g, 80g (packaging and pad boards); 120g and above (heavy-duty protection)
• Core Indicators: Sulfur-free paper sulfur content ≤20ppm; anti-static paper surface resistance 10⁷–10⁹Ω; dust-free paper particle generation ≤Class 10; moisture-proof paper moisture transmission rate ≤5g/m²·24h