Cleanroom Exhaust Pipe Coating for Low-Temperature FM Compliance

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Solution Overview

Problem

Current air exhaust or air-and-smoke exhaust pipes for clean rooms face challenges in meeting FM 4922 and FM 4910 standards due to issues such as generation of poisonous gases, high construction temperatures, and difficulties in construction processes, particularly with existing fluoropolymer coatings.

Innovation Solution

A stainless steel pipe coated with a liquid coating comprising a copolymer of fluorinated alkene and vinyl ether, combined with a siloxane-based polymer and isocyanate, which forms a cross-linked structure for improved heat decomposition resistance and ease of application at lower temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluoropolymer powder coating is used to line the metal pipe, then corrosion resistance and flame retardance are improved, but construction temperature becomes too high (275-315°C) causing high energy consumption and low construction efficiency

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidconstruction temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the chemical structure parameters of the fluoropolymer by introducing vinyl ether groups and copolymerizing with fluorinated alkene, which lowers the glass transition temperature and enables the coating to be applied at room temperature or low temperatures instead of requiring 275-315°C high temperature curing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating system by combining fluorinated alkene copolymer with vinyl ether groups, integrating the corrosion resistance of fluoropolymers with the low-temperature processability of vinyl ether polymers, achieving both protective function and ease of construction

Inventive Principle:
Principle #40Composite materials

2Reliability

If fluoropolymer powder coating is used to line the metal pipe, then corrosion resistance and flame retardance are improved, but the coating process becomes difficult due to powder application requirements

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidconstruction ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the physical state parameter of the coating material from powder to liquid solution by dissolving the fluorinated alkene copolymer in appropriate solvents, transforming the application process from complex powder coating to simple liquid brushing or spraying

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces solvent as an intermediary medium to dissolve the polymer and enable liquid coating application, allowing the coating to be applied in liquid form and then dried to form the protective layer, avoiding all powder handling issues

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If vinyl resin is used for the lining layer, then the pipe structure is simplified, but poisonous gas is generated after burning failing FM 4922 standard

Engineering Contradiction:
Improvepipe structureVSAvoidpoisonous gas generation
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent uses fluorinated alkene copolymer with vinyl ether groups, which maintains the simplicity of a single-layer coating structure while replacing the harmful vinyl resin with a fluoropolymer-based material that does not generate poisonous gases when burned, thus passing FM 4922 flammability tests

Inventive Principle:
Principle #40Composite materials

4Reliability

If high construction temperature is used for powder coating, then adequate coating performance is achieved, but energy consumption increases and construction efficiency decreases

Engineering Contradiction:
Improvecoating performanceVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the thermal parameter of the coating system by incorporating vinyl ether groups that reduce the glass transition temperature, allowing the coating to achieve adequate performance at room temperature or low temperature curing instead of requiring 275-315°C high temperature processing, thereby dramatically reducing energy consumption

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a corrosion-resistant, flame-retardant, and low-temperature construction air exhaust or air-and-smoke exhaust pipe that meets FM 4922 and FM 4910 standards, reducing energy consumption and operational costs while avoiding the generation of hazardous gases.

Implementation Method 1

a copolymer of fluorinated alkene and vinyl ether is selected as a basic film former to form a liquid coating. Because hydroxyl and carboxyl functional groups are introduced, the polymer can be desirably dissolved into a ketone or ester solvent or the like to form a solution

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

combined with a siloxane-based polymer and isocyanate, which forms a cross-linked structure for improved heat decomposition resistance

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 3

A polymer having an F—C structure has good characteristics of corrosion resistance, flame retardance, high temperature resistance, and no stickiness

Methodology Applied
Scientific EffectCorrosion resistance:

Implementation Method 4

A polymer having an F—C structure has good characteristics of corrosion resistance, flame retardance, high temperature resistance

Methodology Applied
Scientific EffectFlame retardance:

Data Source

PatentUS11279111B2Air exhaust or air-and-smoke exhaust pipe for clean room and manufacturing method therefor
Publication Date: 2022.03.22 BAMSTONE NEW MATERIAL TECH (WUHAN) CO LTD

AI summary

The present invention provides an air exhaust or air-and-smoke exhaust pipe for a clean room and a manufacturing method thereof. The air exhaust or air-and-smoke exhaust pipe is a pipe that satisfies FM4922, FM4910, or another equivalent standard and that is used for exhausting nonflammable chemical gas and corrosive vapor or nonflammable chemical gas, corrosive vapor and smoke in fire. The manufacturing method for the air exhaust or air-and-smoke exhaust pipe is: coating an inner part of a pre-manufactured metal pipe with a liquid coating that can be initially dried at normal temperature or low temperature to obtain an inner coating pipe; and baking the inner coating pipe at a temperature not exceeding 250° C. after the coating is initially dried, thus the coating is completely dried to obtain a finished product.