One cannot simply rely on the wide usage temperature range, good elasticity, or the ability to be placed at room temperature for 72 hours after mixing of the product injection liquid silicone 9150-40B, to directly conclude that it is suitable for all computer keypads, keyboard protective covers, seals, mobile phone cases, or glass fiber surface coating systems. One must first confirm the A/B mixing ratio, the uniformity of mixing, vacuum defoaming, injection temperature and mold temperature, curing time, substrate type, environmental cleanliness, and dilution ratio, before determining whether the problem is caused by platinum catalyst poisoning, uneven mixing, insufficient curing, or poor compatibility with the substrate and molding process. Product 9150-40B can be considered as a candidate for injection/spray liquid silicone for curing, but it must undergo small-scale tests, curing verification, and actual working condition confirmation.


Why do injection-cured liquid silicone often fail to meet expectations in low-temperature rebound or curing?


If the A/B components are not accurately measured in a 1:100 ratio or are not mixed evenly, it leads to insufficient cross-linking density or incomplete curing in some areas.


The rubber material comes into contact with compounds such as As, Hg, Sn, N, P, S, etc., causing platinum catalyst poisoning and resulting in poor curing or non-curing.


Although it can be placed at room temperature for 72 hours after mixing, if it exceeds the applicable period or the storage temperature is inappropriate, the rubber material's activity and fluidity decrease.


Insufficient vacuum defoaming, with residual bubbles in the injection component or coating, affects appearance, mechanical properties, and sealing performance.


The injection temperature, mold temperature, or curing time do not match the thickness of the product, resulting in insufficient curing or over-curing, and a decrease in low-temperature rebound performance.


The substrate surface is not cleaned or has oil stains, release agents, or residual additives, affecting the adhesion and uniformity of the coating.


The dilution ratio or the choice of diluent affects the self-extinguishing V0 condition of the glass fiber surface coating.


When switching from other liquid silicone, mixers, or coating materials, the A/B ratio, defoaming, and curing conditions are not adjusted.


Improper storage conditions or exceeding the 120-day storage period lead to a decrease in the activity of the A/B components, affecting the consistency of curing.


The injection machine, mold, or metering equipment has dead zones or cross-contamination, causing platinum catalyst poisoning or batch fluctuations.


In low-temperature application scenarios, the rebound and compression permanent deformation at -60 degrees Celsius are not verified, and the use temperature range is solely relied upon for judgment.


In electronic industry fiberglass coatings, the thickness and curing conditions of the diluted coating are not verified according to the self-extinguishing V0 requirements.


The structure and thickness of the product or the mold exhaust design are unreasonable, resulting in insufficient curing, bubbles, or internal stress concentration in some areas.


First, determine which stage the curing or low-temperature rebound problem occurs.


Failure stage Possible causes Priority inspection direction
Post-mixing non-curing or incomplete curing A/B ratio deviation, mixing unevenness, platinum catalyst poisoning Accuracy of measurement, mixing efficiency, environmental cleanliness
Injection component surface sticky or curing slow Mold temperature insufficient, catalyst poisoning, expired rubber material Examination of mold temperature, pollutant removal, storage conditions
Injection component with bubbles or voids Insufficient vacuum defoaming, inappropriate injection speed or pressure, poor mold exhaust Defoaming process, injection parameters, mold exhaust
Insufficient hardness or strength of the product Low cross-linking density, A/B ratio deviation, insufficient curing A/B ratio, curing temperature and time
Insufficient low-temperature rebound or large compression deformation Low cross-linking density, unverified low-temperature performance, poor plasticizer or filler matching Low-temperature rebound, compression permanent deformation, formula verification
Poor coating adhesion or detachment Bad substrate cleaning, excessive coating thickness, insufficient curing Surface treatment, coating thickness, curing conditions
Self-extinguishing V0 of the fiberglass coating not reached Deficiency in dilution ratio, coating thickness, curing degree Deficiency in dilution process, coating thickness, flame retardant verification
Batch-to-batch curing or performance fluctuations A/B component activity difference, storage conditions, measurement error Inspection upon entry, storage records, accuracy of measurement
If one only focuses on whether product 9150-40B was used, but fails to record the A/B ratio, degassing, injection/coating conditions, substrate and contaminant control, it is usually difficult to accurately determine whether it is a material issue or a process issue.


Why is merely increasing the curing temperature or increasing the A/B dosage not necessarily effective?


Product 9150-40B plays a role in platinum addition curing in the system. It is affected by the A/B ratio, degassing, curing temperature, substrate and catalyst poison. Simply increasing the temperature or dosage may cause side effects.


Increasing the mold temperature or curing temperature may result in over-sulfurization on the surface or damage to the substrate, while the interior is still not fully cured. The low-temperature rebound may even worsen.


Increasing the total dosage of A/B does not change the 1:100 ratio requirement. Excessive adhesive will not increase the crosslinking density, but will cause waste.


Extending the curing time may improve deep curing, but it may affect production efficiency and the demolding performance of the product.


Increasing the dilution ratio may improve the coating thickness and feel, but it may reduce self-extinguishing and protective performance.


After platinum catalyst poisoning, increasing the temperature or extending the curing time cannot normally cure.


When the substrate surface is not cleaned, only adjusting the curing conditions cannot solve the adhesion problem.


When degassing is insufficient, only increasing the temperature may cause bubble expansion, affecting the appearance and low-temperature performance of the product.


If the insufficient low-temperature rebound is due to the formula or crosslinking density, only adjusting the curing temperature cannot fundamentally improve the elasticity recovery at -60 degrees Celsius.


Therefore, when optimizing, one should observe the A/B ratio, degassing, curing conditions, substrate treatment, contaminant control and low-temperature performance verification simultaneously, rather than only adjusting a single parameter.


What are the differences between product 9150-40B and product 9250-40B and similar molding schemes?


Comparison direction Product 9150-40B (thermoplastic injection/coating liquid silicone) Product 9250-40B (thermoplastic injection/coating liquid silicone) Molded rubber injection molding General condensation type silicone Selection boundary
Operating temperature -60℃ to 250℃ -40℃ to 250℃ Depending on the formula Generally Lower temperature scenarios are prioritized for evaluation of 9150-40B
Hardness (Shore A) 39±2 38±2 Depending on the formula Depending on the formula Choose based on the softness requirements of the product
Tensile strength ≥4.6 MPa ≥4.4 MPa Depending on the formula Generally Choose based on the mechanical strength requirements
Elongation ≥510% ≥500% Depending on the formula Generally Choose based on the rebound and deformation requirements
Tear strength ≥15.2 kN/m ≥13.2 kN/m Depending on the formula Generally Choose based on the anti-tear requirements
Storage after mixing at room temperature 72 hours allowed 72 hours allowed After sulfurization, prone to dead material Shorter applicable period Choose based on production rhythm and applicable period
Sensitivity to platinum catalyst poisoning Sensitive to As, Hg, Sn, N, P, S, etc. Sensitive to As, Hg, Sn, N, P, S, etc. Depending on the system Not involving platinum Strictly control substrate and equipment contamination
Low-temperature performance -60℃ operating temperature indicated in the data, need to verify low-temperature rebound -40℃ operating temperature indicated in the data Depending on the formula Generally Low-temperature scenarios need to be specifically verified
Application scenarios Computer keypads, keyboard covers, seals, phone cases, glass fiber coatings Similar industrial and electronic applications Molded and injection General sealing Choose based on the product and working conditions
Why does compatibility with the substrate and molding process still require complete tests?


Our company's public information states that product 9150-40B is used for injection-molded silicone rubber products such as computer keypads and keyboard covers, seals, and phone cases, as well as for glass fiber surface coatings after appropriate dilution, with a self-extinguishing level up to V0 grade. However, when used in actual systems, the following may also exist:


Differences in substrate type, surface treatment, and temperature resistance.


A/B measurement accuracy, mixing uniformity, and vacuum degassing.


Injection machine, mold temperature, and exhaust design.


Matching of curing temperature, time, and product thickness.


Dilution ratio and compatibility of diluent.


Environmental cleanliness and control of platinum catalyst toxins.


The effect of pigments, additives, and release agents on curing.


Self-extinguishing property, adhesion, and insulation performance of the fiberglass coating.


Low-temperature rebound, compression permanent deformation, and thermal aging performance.


Storage conditions and A/B component activity.


Batch-to-batch curing consistency and product appearance.


Appearance semi-transparent or short-term curing reaching the standard, which cannot prove the stability of long-term use, low-temperature rebound, heat resistance aging, or flame retardancy. Before use, verification should be conducted using the complete formula, actual substrate, and working conditions.


Which parameters should be confirmed when using product 9150-40B?


Parameter category Required information
Application direction Computer keypads, keyboard covers, seals, phone cases, fiberglass surface coating
Substrate type Plastic, metal, glass fiber, electronic components
Surface treatment Cleaning method, drying degree, presence of oil and release agent
A/B ratio 1:100, measurement accuracy and mixing uniformity
Degassing process Vacuum degassing conditions, time, vacuum degree
Injection/Coating conditions Mold temperature, injection speed, pressure, coating thickness
Curing conditions Adjust temperature and time according to product thickness and size
Dilution process Dilution ratio, diluent type, compatibility
Environmental cleanliness Avoid As, Hg, Sn, N, P, S, etc. platinum catalyst toxins
Low-temperature performance Rebound, compression permanent deformation, sealing at -60°C
Storage conditions Avoid light, exposure to direct sunlight, water, fire, storage period 120 days
Acceptance indicators Appearance, density, hardness, tensile strength, elongation, tear strength, adhesion, self-extinguishing property, low-temperature rebound
What should be primarily verified when using product 9150-40B?


A/B measurement accuracy and mixing uniformity.


Vacuum degassing effect and internal air bubbles in injection components/coatings.


Hardness, tensile strength, elongation, and tear strength of the cured product.


Rebound, heat resistance aging, and dimensional stability of the injection component.


Low-temperature rebound and compression permanent deformation at -60°C.


Adhesion between the coating and glass fiber.


Self-extinguishing condition of the diluted fiberglass coating reaching V0 level.


Influence of substrate, pigments, and additives on platinum catalyst.


Performance stability at 250°C.


Flowability and curing activity of the mixture within 72 hours after mixing.


Batch-to-batch curing consistency and product appearance.


Activity and curing speed of A/B components within 120 days of storage.


How to design experiments before using product 9150-40B?


Establish a current liquid silicone rubber or coating benchmark, record model, A/B ratio, degassing, injection/coating conditions, and failure performance.


Uniform test conditions: substrate, surface treatment, A/B ratio, degassing process, mold temperature, injection speed, coating thickness, curing conditions.


Set candidate samples: current material, product 9150-40B, product 9250-40B, different curing conditions or dilution ratio gradients.


Complete the entire process test: mixing → degassing → injection/coating → curing → performance test → low-temperature/thermal aging/resistance to flame retardancy verification.


Evaluate actual results: appearance, hardness, strength, elongation, tear strength, adhesion, self-extinguishing property, low-temperature performance.


Test items Uniform requirements
Base material and surface treatment Consistent
A/B ratio 1:100
Defoaming process Consistent
Injection/coating conditions Set gradients according to the test design
Curing conditions Set gradients according to the test design
Dilution ratio Set gradients according to the test design
Low-temperature test conditions Set according to the actual lowest temperature
Measurement methods Appearance, hardness, strength, elongation, tear strength, adhesion, self-extinguishing property, resilience consistent
Which situations are not suitable for directly using product 9150-40B?


A/B metering accuracy cannot be guaranteed or the mixture is not uniform, resulting in incomplete curing.


The base material or the environment contains platinum catalyst toxins such as As, Hg, Sn, N, P, S, etc., causing poor curing.


After mixing for more than 72 hours or with improper storage temperature, the rubber material's activity decreases.


Insufficient vacuum defoaming, with residual bubbles in the injection component or coating, affecting appearance and performance.


The base material has insufficient temperature resistance, and the curing temperature may damage the base material or electronic components.


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


There are clear dilution ratios and coating thickness requirements for self-extinguishing V0, but they have not been verified under actual conditions.


Only have the application direction, but no base material, A/B ratio, curing and injection/coating data.


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


When switching from other liquid silicone or coatings, the dilution and curing processes have not been adjusted.


Storage conditions do not meet the requirements of avoiding light, waterproof and fireproof, or exceeding the 120-day storage period.


Low-temperature application scenarios have not been verified - rebound and sealing performance at -60℃, judged only by the temperature range.


What selection support can our company provide?


As a provider of the entire organic silicone value chain, our company can assist in comparing the applicability of injection liquid silicone 9150-40B with compression molding injection/coating liquid silicone in different base materials, molding methods and low-temperature conditions.


For computer keypads, seals, phone cases or fiberglass coatings projects that need to balance low-temperature rebound, heat aging resistance, dimensional stability and self-extinguishing properties, before selection, provide:


Application direction and base material type.


Target hardness, rebound and heat aging requirements.


Minimum operating temperature and low-temperature rebound requirements.


A/B ratio, defoaming and curing conditions.


Injection machine, mold temperature, injection speed and coating thickness.


Dilution ratio and diluent type.


Compatibility of base material, pigments, additives and platinum catalysts.


Self-extinguishing V0 and adhesion requirements.


Current material model, ratio and failure performance.


Acceptance methods and applicable standards.


After receiving complete materials, we can determine whether to prioritize testing a certain curing and dilution scheme of product 9150-40B, or choose product 9250-40B or other liquid silicone routes.


Common Misconceptions


The A/B ratio can have a slight deviation.
The usage ratio of product 9150-40B is 1:100. Deviation or uneven mixing can lead to incomplete curing or performance degradation. Precise measurement is required.


After mixing, it can be left at room temperature for 72 hours, and then production can be arranged at will.
72 hours is the upper limit for room temperature storage. Storage temperature, humidity, and contamination can affect the shelf life. It should be used under verified conditions.


The poisoning of platinum catalyst can be ignored.
Contact with compounds such as As, Hg, Sn, N, P, S can cause poor curing. Strict control of substrate, pigment, equipment, and environmental pollution is necessary.


The temperature marking -60℃ can directly be used for all low-temperature sealing.
Low-temperature rebound, compression permanent deformation, and sealing performance need to be specially verified at -60 degrees Celsius. It cannot be judged solely based on the temperature range.


Product 9150-40B and product 9250-40B can be interchanged freely.
There are differences in hardness, tensile strength, elongation, tear strength, and temperature range of use between the two. When replacing, the low-temperature performance, curing conditions, and molding process need to be re-verified.


Compatibility with the substrate allows for direct injection or coating.
It is still necessary to confirm surface cleanliness, A/B ratio, defoaming, curing conditions, and pollutant control.


The dilution ratio does not affect self-extinguishing property.
The dilution ratio and coating thickness jointly affect the achievement of V0 self-extinguishing property. It needs to be verified under actual conditions.


It can still be used after 120 days of storage.
The storage period is 120 days. After expiration or improper storage, it is necessary to re-test the activity and curing performance of the A/B components.


Recommended selection steps


Confirm the application direction: computer keys, keyboard covers, seals, phone cases, or fiberglass surface coatings.


Confirm the substrate type, surface treatment, and temperature resistance conditions.


Confirm the minimum use temperature and low-temperature rebound requirements.