One cannot simply rely on the low oil resistance volume change rate of the FLSR3400 series or the hardness data after one-time vulcanization to directly determine that it is suitable for all automotive, marine, aerospace, power electrical, and consumer electronic oil-resistant components. One should first confirm the usage temperature, contact medium, hardness and compression permanent deformation requirements, mixing ratio, degassing process, one-time vulcanization and secondary vulcanization conditions, and then compare products FLSR3440 and FLSR3460. The FLSR3400 series can be considered as a candidate direction for bulk liquid fluorosilicone rubber, but it must be confirmed through small-scale tests, vulcanization verification and medium immersion tests.


Why does bulk liquid fluorosilicone rubber often fail to achieve the expected results in oil-resistant sealing?


The A/B component mixing ratio deviates from 1:1 or the mixing is not thorough, resulting in insufficient local crosslinking density or incomplete curing.


The gel liquid comes into contact with compounds containing nitrogen, sulfur, phosphorus and heavy metals, causing poisoning of the platinum catalyst and incomplete or non-curing.


Insufficient vacuum degassing, with residual bubbles in the gel layer, affecting tensile strength, tear strength and sealing reliability.


Insufficient one-time vulcanization temperature or time, and insufficient secondary vulcanization, resulting in excessive compression permanent deformation and insufficient resilience.


The hardness, elongation and compression permanent deformation of products FLSR3440 and FLSR3460 differ significantly, and the selection was not made according to the product requirements.


The contact medium exceeds the verification conditions, such as ketones, esters, strong acids or high aromatic fuel oil, resulting in an excessive volume change rate.


The usage temperature exceeds the applicable range of fluorosilicone rubber, with insufficient rebound at low temperatures or accelerated aging at high temperatures.


The substrate surface is not cleaned or has oil stains, release agents, or oxidation layers, affecting adhesion and sealing.


The molding process and material viscosity do not match, and the molding, coating or injection molding parameters are not optimized, resulting in defects in the product interior.


From the general fluorosilicone blend rubber, single-component fluorosilicone sealant or ordinary silicone rubber, when switching, the mixing, degassing and vulcanization conditions should not be adjusted again.


The storage conditions are improper, with A/B components absorbing moisture or expiring, affecting the curing activity and batch consistency after mixing.


The statements of the FSR8400 series in the usage method section should be verified and confirmed with the effective TDS of the FLSR3400 series before implementing the vulcanization conditions.


First, determine which stage the curing or sealing problem occurs.


Failure stage Possible causes Priority inspection direction
Not curing or incomplete curing after mixing Proportion deviation, insufficient mixing, platinum catalyst poisoning Proportion, mixing efficiency, environmental cleanliness
Presence of bubbles or voids in the product Insufficient degassing, mismatch between viscosity and molding process Vacuum degassing, mold exhaust, injection parameters
Insufficient strength or elongation after one-time vulcanization Insufficient vulcanization temperature or time, low crosslinking density One-time vulcanization conditions, A/B ratio
The compression permanent deformation is still excessive after secondary vulcanization Insufficient secondary vulcanization, mismatch of fillers or crosslinking system Secondary vulcanization conditions, hardness selection
Excessive volume change rate after oil immersion Medium beyond verification range, mismatch of fluorine content or crosslinking density Medium type, temperature, time, selection
Insufficient rebound at low temperatures or sealing failure High hardness, insufficient flexibility at low temperatures Low temperature performance, hardness, compression ratio
The product surface becomes sticky or sticks to the mold Insufficient vulcanization, mold contamination, mismatch of release agent Vulcanization conditions, mold cleanliness
Batch-to-batch performance fluctuations Batch differences in raw rubber or fillers, uneven mixing Incoming inspection, mixing and vulcanization records
If only focusing on "whether the FLSR3400 series was used", without recording the mixing ratio, degassing, vulcanization conditions and medium contact situation, it is usually difficult to accurately determine whether it is a material problem or a process problem. 


How should FLSR3440 and FLSR3460 be selected?


Operating conditions Product FLSR3440 candidate direction Product FLSR3460 candidate direction Still need verification
Low hardness high elongation seal After one-time vulcanization, hardness is 39 and elongation is 425%, suitable for flexible seal Hardness is 59 and elongation is 235%, with lower flexibility Compression ratio, rebound, low-temperature performance
High hardness high modulus component Lower hardness, possibly insufficient support After one-time vulcanization, hardness is 59 and after secondary vulcanization, it is 62%, suitable for higher stiffness Compression permanent deformation, assembly stress
Low pressure priority After secondary vulcanization, compression permanent deformation is 4% After secondary vulcanization, compression permanent deformation is 6% Actual temperature, time, compression ratio
One-time vulcanization after low pressure change 10% after one-time vulcanization 20% after one-time vulcanization, requires secondary vulcanization Whether secondary vulcanization conditions are available
Resistant to Fuel C and FAM B 22.2% for Fuel C, 28.8% for FAM B 20.5% for Fuel C, 28.0% for FAM B, slightly better Actual fuel, temperature, long-term immersion
Resistant to diesel and IRM903 3.3% for Fuel F Diesel, 2.2% for IRM903 2.4% for Fuel F Diesel, 2.0% for IRM903, diesel slightly better Medium batch, temperature, time
Resistant to Jet Fuel No.3 4.9% 5.1% Aircraft fuel actual conditions
Compression molding or coating molding Lower viscosity, high elongation, suitable for complex surfaces Higher viscosity, higher hardness, suitable for dimensionally stable components Mold design, vulcanization efficiency
Injection molding Need to evaluate flowability and vulcanization rate Need to evaluate filling and排气 under high hardness conditions Injection parameters， mold temperature
Can only choose based on hardness， because the elongation， compression permanent deformation and medium resistance data of the two models differ. The final choice depends on the sealing structure， compression ratio， medium type and vulcanization conditions.


What are the differences in product selection between the FLSR3400 series and similar oil-resistant solutions?


Comparison direction FLSR3400 series (additive-based liquid fluorosilicone rubber) Fluorosilicone compound One-component fluorosilicone sealant General silicone rubber Fluororubber
Molding method Bi-component liquid， compression molding， coating， injection molding Compounding， compression molding， extrusion One-component room-temperature vulcanization Compounding or liquid gel Compounding
Oil resistance Excellent， covers IRM903， diesel， Fuel C， etc. Excellent Excellent Poor Excellent
Low-temperature flexibility Good Good Good Good Poor
Deep curing Additive-based can be deeply vulcanized Depends on vulcanization process Wet gas curing is limited by depth Additive-based can be deeply Depends on the system
Compression permanent deformation Lower after secondary vulcanization Need to verify according to the formula Not marked Generally Generally
Toxicity sensitivity of catalysts Sensitive to N， P， S and heavy metals Sensitive to platinum-based system Not involving platinum Sensitive to platinum-based system Varies depending on the system
Application scenarios Automobile， ships， aerospace， power and electrical， oil-resistant components for base materials Sealing parts， pipes， flanges， oil tank filling gaps General sealing， universal sealing Strong chemical medium sealing
Why are complete tests still needed for compatibility with base materials and media?


Aydota's public information states that the FLSR3400 series is used for oil-resistant components in automotive， ships， aerospace， power and electrical， etc.， and can be extended to consumer electronics， wearable products and medical care. However， when used in actual systems， there may still be：


Differences in base material types and surface treatments.


Types， concentrations and temperatures of contact media.


Temperature range of use and requirements for low-temperature rebound.


Mixing ratio， stirring efficiency and degassing conditions.


Environmental cleanliness and control of platinum catalyst poisons.


One-time vulcanization and secondary vulcanization conditions.


Molding process and product thickness.


Long-term volume changes and mechanical property retention rates after oil immersion.


Low-temperature cycling and high-temperature aging.


Storage conditions and packaging sealing.


Uniform appearance or short-term performance compliance, which does not prove stability after long-term oil immersion, thermal cycling or vibration. Verification should be conducted using the complete formulation and actual materials before use.


Which parameters should be confirmed when using the FLSR3400 series of products?


Parameter category Required information
Application direction Automotive oil-resistant components, marine sealing, aerospace oil-resistant parts, power electrical insulation parts
Base material type Metal, plastic, ceramic, PCB, coated surface
Surface treatment Cleaning method, degreasing, grinding, primer application
Contact medium Dextron III, IRM903, RME Biodiesel, diesel, Fuel C, FAM B, Jet Fuel No.3
Operating temperature Long-term temperature, peak temperature, low-temperature rebound
Hardness and compression Target Shore A, compression rate, rebound requirements
Mix ratio A:B = 1:1 (mass ratio), uniformity of mixing
Defoaming process Vacuum defoaming conditions, time, vacuum degree
Sulfurization conditions First sulfidation at 120°C for 10 minutes, second sulfidation at 200°C for 4 hours, adjusted according to product thickness
Environmental cleanliness Avoid platinum poisons such as N, P, S and heavy metals
Storage conditions Cold and dry, unopened, twelve months
Acceptance indicators Hardness, tensile strength, elongation, tear strength, rebound, compression permanent deformation, volume change rate
What should be focused on verifying when using the FLSR3400 series of products?


A/B mixture uniformity and vacuum defoaming effect.


Hardness, tensile strength, elongation and tear strength after first sulfidation and second sulfidation.


Compression permanent deformation and rebound.


Volume change rate after immersion in Dextron III, IRM903, RME Biodiesel, diesel, Fuel C, FAM B, Jet Fuel No.3.


Rebound and sealing reliability at low temperatures.


Mechanical property retention rate after high-temperature aging.


Adhesion to the base material and compatibility of the sealing structure.


Impact of molding process on the internal quality of the product.


Effect of environmental cleanliness on the curing quality.


Batch-to-batch consistency and repeatability.


How to design tests before using the FLSR3400 series of products?


Establish a current fluorosilicone material benchmark, record model, batch, mixing ratio, sulfurization conditions and failure performance.


Uniform test conditions: base material, surface treatment, mixing ratio, defoaming process, first sulfidation, second sulfidation, molding process.


Set candidate samples: current material, product FLSR3440, product FLSR3460.


Complete the full process testing: mixing → defoaming → molding → first sulfidation → second sulfidation → performance testing → medium immersion.


Evaluate actual results: hardness, strength, elongation, tear strength, rebound, compression permanent deformation, volume change rate.


Test items Uniform requirements
Base material and surface treatment Consistent
Mix ratio A:B = 1:1
Defoaming process Consistent
First sulfidation conditions Set gradients according to test design
Second sulfidation conditions Set gradients according to test design
Environmental cleanliness Prevent platinum poison contamination
Immersion conditions Set according to actual working conditions
Measurement method Hardness, strength, elongation, tear strength, rebound, compression permanent deformation, volume change rate are consistent
Under which circumstances should the FLSR3400 series of products not be directly used?


The base material surface is not cleaned or not coated with a primer, affecting adhesion.


There are platinum catalyst poisons such as N, P, S and heavy metals in the environment, leading to non-curing.


The incorrect mixing ratio or insufficient stirring results in incomplete curing.


Insufficient vacuum degassing leads to residual air bubbles in the adhesive layer, affecting the sealing and mechanical properties.


Specific food contact, medical or airworthiness approvals are required, but corresponding documents have not been obtained yet.


The contact medium exceeds the validation range, such as ketones, esters, and strong acids.


The operating temperature exceeds the applicable range of fluorosilicone rubber.


Only the medium type is known, without the base material, mixing ratio and curing conditions data.


The customer requests to directly mix it into the in-use system, but cannot control the mixing ratio and degassing conditions.


The storage conditions do not meet the requirements of cool and dry, unopened, and the rubber may absorb moisture or expire after storage.


The requirement for permanent compression deformation after one-time curing is strict, but product FLSR3460 has a 20% permanent compression deformation after one-time curing, and it is not suitable to be subjected to secondary curing when the conditions for secondary curing are not available.


The statements of the FLSR8400 series in the usage method section were executed without effectively comparing with the TDS of the FLSR3400 series of products.


What selection support can Aytota provide?


As an integrated solution provider for organic silicon全产业链， Aytota can assist in comparing the applicability of the additively formed liquid fluorosilicone rubber in different substrates， media and curing conditions for the FLSR3400 series products.


For automotive， shipbuilding， aerospace or power and electrical oil-resistant component projects that need to balance oil resistance， low-temperature resistance， pressure variation resistance and reliable sealing， the following information should be provided before selection：


Substrate type and surface treatment method.


Contact medium type， concentration and temperature.


Operating temperature range and low-temperature rebound requirements.


Product hardness， compression rate and size requirements.


Mixing ratio， degassing process and molding method.


One-time curing and secondary curing conditions.


Target hardness， strength， elongation， resilience， compression permanent deformation and volume change rate.


Current material model， mixing ratio and failure performance.


Acceptance methods and applicable standards.


After receiving complete materials， it can be determined whether to prioritize testing the product FLSR3440， the product FLSR3460， or choose another oil-resistant elastomer route.


Common misunderstandings


Oil resistance volume change rate can be used for all fuels and lubricants
Different media have different swelling effects on fluorosilicone rubber. Fuel C， FAM B， Jet Fuel No.3， IRM903， etc. need to be verified separately.


The FLSR3440 and FLSR3460 products can be interchanged freely
There are differences in hardness， elongation， compression permanent deformation and media resistance data between the two， and when replacing， the sealing structure， compression rate and curing conditions need to be re-verified.


One-time curing can achieve the final compression permanent deformation
The compression permanent deformation of product FLSR3460 after one-time curing is 20%， and it drops to 6% after secondary curing， and secondary curing should be carried out according to the recommended conditions.


The A/B mixing ratio can have a slight deviation
1：1 is the mass ratio， deviation may lead to incomplete curing or performance decline， it is necessary to precisely control.


Platinum catalyst poisons can be ignored
Contacting the compound containing N， P， S and heavy metal elements in the gel will cause insufficient or non-sulfurization， it is necessary to strictly control the environmental cleanliness.


Compatibility with the substrate can directly form
It is still necessary to confirm surface cleanliness， primer， mixing ratio， degassing， curing conditions and long-term oil immersion stability.


The FLSR3400 series products can be used for all oil-resistant seals
Additively formed liquid fluorosilicone rubber is suitable for oily environments and low-temperature conditions， for systems with higher temperatures or stronger chemical media， other elastomers may need to be selected.


The statements of the FLSR8400 series in the materials can be directly executed
The statements of FLSR8400 series in the usage method section should be compared and confirmed with the effective TDS of the FLSR3400 series products before executing the curing conditions.
Recommendation of selection steps


Confirm the application direction: automotive oil-resistant components, ship sealing, aerospace oil-resistant parts, or electrical and electronic insulation parts.


Confirm the type of substrate and surface treatment method.


Confirm the contact medium, operating temperature and requirements for low-temperature rebound.


Confirm the hardness, compression ratio and size requirements of the product.


Confirm the mixing ratio, defoaming process and molding method.


Confirm the conditions for one-time vulcanization and two-time vulcanization.


Based on the application scenario, initially select product FLSR3440 or product FLSR3460.


Set different vulcanization conditions and defoaming gradients for small-scale tests.


Test hardness, strength, elongation, tear strength, rebound and compression permanent deformation.