Insulants Panel 3021/3025/Textolite/Pertinax/Текстолит/PFCC/PFCP/Getinaks/NEMA X/XX/XXX Raw Material, Resin, Process and Production Equipment

The following content focuses on GB/T 1303 grade 3021 insulating materials. From the perspective of resin preparation (resin kitchen) and impregnation/lamination process, it summarizes raw materials, resin system, process route, equipment configuration, and performance boundaries.

I. Industry Positioning and Standard Attributes of 3021

• 3021 belongs to phenolic-resin-impregnated paper-based laminated insulating sheet.
• Common English names: Phenolic Paper Laminated Sheet, Phenolic Paper-based Insulating Sheet.
• Applicable standards: GB/T 1303 (aligned with IEC 60893, PFCP category).
• Industry common name: general-purpose paper-based phenolic laminate.

II. Composition of 3021: Raw Materials + Resin System

2.1 Substrate type

Electrical insulating paper, kraft paper, or bleached pulp paper.

Key indicators:

• Basis weight: 120-200 g/m2
• Low ash content
• High impregnation uniformity
• Relatively lower MD/TD strength consistency requirements (vs. fiberglass)

The upper performance limit of 3021 is mainly determined by paper substrate, not downstream processing.

2.2 Resin system (defines 3021 nature)

• Resin type: thermosetting phenolic resin
• Common systems: alkaline or neutral

Typical resin preparation composition:

• Phenol
• Formaldehyde
• Catalyst (for example NaOH or organic amines)
• Diluent/solvent (for example ethanol or methanol)
• Minor modifiers (improving flexibility or reducing brittleness)

Typical resin characteristics:

• Solids content: 45-55%
• Viscosity: medium to low (suitable for full paper impregnation)
• Reaction mechanism: condensation polymerization with water generation

2.3 Why 3021 uses phenolic resin only

From an engineering perspective:

• Paper substrate heat resistance is inherently limited.
• Phenolic resin offers:
• Low curing temperature
• Good flowability
• Lowest overall cost
• Best compatibility with cellulose

This is also why 3021 cannot be easily upgraded to a higher thermal class.

III. Performance Boundaries of 3021 (Engineering View)

The advantage of 3021 is not peak performance, but cost-effectiveness and easy machining.

IV. Complete Manufacturing Process Route for 3021

4.1 Process overview

Phenolic resin preparation -> paper impregnation -> drying to B-stage -> cutting/stacking -> hot-press lamination -> post-curing -> cut-to-size machining.

NTRY applies full-process equipment including resin kitchen, impregnation line, lamination press, and cutting systems.

V. Process Breakdown by Section and Equipment

5.1 Resin preparation section (resin kitchen)

Process characteristics:

• Single-kettle or dual-kettle operation
• Wide reaction window
• Relatively low precision requirement

Key equipment:

• Phenolic resin reactor (kettle)
• Condenser and reflux system
• Solvent metering system
• Resin storage tanks

Compared with FR-4 systems, 3021 resin preparation has a lower process barrier.

5.2 NTRY paper impregnation line (critical but not complex)

Process characteristics:

• Single-bath impregnation
• Resin pickup controlled by metering rollers
• Low web tension requirement

Typical line configuration:

• Unwinder
• Impregnation unit
• Metering/doctor/squeeze rollers
• Multi-zone hot-air oven (120°C-160°C)
• Sheet cutting unit

Process objectives:

• Full fiber impregnation
• Surface dry and non-tacky
• Internal resin still capable of secondary flow during lamination

5.3 B-stage impregnated paper

Required condition:

• Dry surface
• Stackable
• Can re-soften and flow again during heating

Key control points:

• Over-dried: poor interlayer bonding in lamination
• Over-wet: bubbles or delamination

5.4 Hot-press lamination press

Method:

• Atmospheric pressure or slight vacuum hot press

Typical parameters:

• Temperature: 140°C-160°C
• Pressure: 2-4 MPa
• Cycle: 30-60 minutes

Equipment:

• NTRY multi-opening hot press
• Press plate tooling system (caul plates/templates as required)
• Basic programmable pressure-cycle control

5.5 Post-curing and finishing

Post-curing:

• 140°C-150°C
• 8-24 hours
• Improves dimensional and electrical stability

Machining/finishing (third-party facilities can be used):

• Sawing
• Punching
• CNC machining

VI. Engineering Differences vs. Adjacent Grades

VII. Engineering Conclusions (for Equipment/Process Teams)

1. 3021 has one of the highest process tolerances among common insulation sheets.
2. The three most critical controls are:

• Resin solids content
• Paper impregnation degree
• Hot-press deaeration/venting

3. Attempts to significantly improve 3021 performance will still be limited by the intrinsic ceiling of paper substrate.
4. Core value of 3021 production lines:

• Low cost
• Easy machining
• Stable large-volume supply