One cannot simply conclude that IOTA-31 is suitable for all room-temperature vulcanized silicone rubber or neutral silicone rubber sealant systems based solely on its containing a tetra-functional structure component. One should first confirm the type of base adhesive, filler system, moisture content, catalyst dosage, and construction environment before determining whether the problem lies in insufficient crosslinking efficiency, imbalance between surface drying and deep curing, or poor compatibility with the base adhesive and fillers. IOTA-31 can be considered as a candidate for ketoxime-based crosslinking agents, but it must be confirmed through small-scale tests, control of by-products, and actual working conditions.


Why do room-temperature vulcanized silicone rubber or neutral silicone rubber sealants often have slow surface drying or insufficient deep curing?


During storage, moisture absorption leads to the premature hydrolysis of the ketoxime groups, a decrease in effective components, and a weakening of crosslinking activity.


Improper control of moisture in the system results in premature hydrolysis of the crosslinking agent, a reduction in effective concentration, and the release of butanone oxime, which affects the reaction balance.


Improper catalyst type or dosage leads to insufficient crosslinking reaction conversion rate, prolonged surface drying and deep curing times.


The hydroxyl content or molecular weight of the base adhesive does not match the crosslinking agent, resulting in insufficient or excessive crosslinking density or a decrease in the sealing agent's flexibility.


The surface treatment differences of the filler system (such as silica, calcium carbonate) affect the dispersion of the crosslinking agent and the uniformity of the reaction.


The mismatch of construction environment temperature and humidity leads to deviations in surface drying time and deep curing time from expectations.


Insufficient purity or presence of impurities interferes with the crosslinking reaction, affecting the strength, elongation rate, and aging resistance of the final silicone rubber.


The TOS content (18-20%) has not been optimized for specific systems, and excessive or insufficient amounts affect the crosslinking efficiency and storage stability.


The four-functional structure can increase strength, but it may result in excessive crosslinking density, brittle products, or decreased sealing agent extrudability.


Compared with similar crosslinking agents such as IOTA-32, there are significant differences in TOS content, and the addition amount or catalyst system should not be adjusted when replacing.


What are the public parameters of IOTA-31?


Parameter IOTA-31
Appearance Transparent liquid from colorless to pale yellow
Boiling point 330℃/760mmHg
Refractive index (25℃) 1.4585±0.0020
TOS content (%) 18-20
Specific gravity (25℃) 0.980±0.005 g/ml
pH value 7.0±0.5
The above data are from Aytota's current public product information. Formal procurement and batch acceptance should be based on the valid TDS, specification documents, and delivery batch COA confirmed by both parties.


Which application directions is IOTA-31 suitable for?


Application direction Candidate direction Still needs verification
Room-temperature vulcanized silicone rubber crosslinking agent Increase strength, shorten surface drying and deep curing time Selection of base adhesive type, dosage, catalyst matching
Neutral silicone rubber sealant As a crosslinking agent, improve curing efficiency Fillers system, storage stability, extrudability
Electronic potting adhesive Increase crosslinking density and mechanical strength Electrical performance, aging resistance, deep curing
Building sealant Shorten surface drying time, improve construction efficiency Construction environment, adhesion, weather resistance
Four-functional crosslinking system Provide higher crosslinking density Brittleness, elongation rate, sealing agent flexibility
What are the differences in selection priorities between IOTA-31 and similar crosslinking agents?


Comparison direction IOTA-31 (methyl mixed ketoxime) IOTA-32 (methyl mixed ketoxime) IOTA-91 (ethylene mixed ketoxime) Selection boundary
TOS content (%) 18-20 9-12 27-35 Select based on the hydroxyl content of the base adhesive and curing requirements
Crosslinking mechanism Contact water crosslinking, release butanone oxime Contact water crosslinking, release butanone oxime Contact water crosslinking, release butanone oxime Select based on substrate and environmental protection requirements
Drying speed Relatively fast, four functional groups can shorten the drying time on the surface Relatively fast, four functional groups can shorten the drying time on the surface Relatively fast, when combined with MOS/VOS, it can shorten the film formation time Needs to be verified according to the construction conditions
Deep curing Four functional groups can shorten the deep curing time Four functional groups can shorten the deep curing time Higher crosslinking density Needs to be verified according to the thickness of the product
Crosslinking density TOS content is higher, and the crosslinking density is higher TOS content is lower, and the crosslinking density is moderate Higher crosslinking density Needs to be selected according to the hardness and elongation requirements of the product
Corrosion of the substrate Neutral, no corrosion Neutral, no corrosion Neutral, no corrosion Ketoxime type is suitable for metal substrates
By-product odor Butanone oxime odor Butanone oxime odor Butanone oxime odor Needs to be selected according to the construction environment requirements
Storage stability Needs to be sealed and protected from moisture Needs to be sealed and protected from moisture Needs to be sealed and protected from moisture All need to be stored in a moisture-proof environment
Applicable systems Room temperature vulcanized silicone rubber, neutral silicone glass adhesive Room temperature vulcanized silicone rubber, neutral silicone glass adhesive Single-component neutral silicone sealant Needs to be selected according to the base adhesive and filler
Why is it still necessary to conduct a complete test for compatibility with the base adhesive and fillers?


The public information of Aytota states that IOTA-31 is used as a crosslinking agent in room temperature vulcanized silicone rubber and neutral silicone glass adhesive, which can improve the strength of the silicone rubber, shorten the surface drying time and deep curing time. However, when used in actual systems, there may still be:


Differences in the hydroxyl content and molecular weight of the base adhesive.


Types of fillers and surface treatments.


Types and dosages of catalysts.


Plasticizers, coupling agents and other additives.


Residual moisture and contaminants.


Temperature and humidity of the construction environment.


Storage conditions and packaging sealing.


Thickness of the product and curing time requirements.


Recombinations ratio with other crosslinking agents.


Appearance uniformity or no short-term stratification cannot prove stability in long-term storage, thermal cycling, shear and long-term operation. Before use, a complete formulation and actual materials should be used for verification.


What parameters should be confirmed when using IOTA-31?


Working condition category Information to be confirmed
Base adhesive system Hydroxyl content, molecular weight, type (107 adhesive, methyl silicone rubber, etc.)
Filler type White carbon black, calcium carbonate, silicon powder, etc.
Catalyst system Type and dosage of organic tin, titanium acid ester or other catalysts
Crosslinking agent addition amount Determined based on TOS content and hydroxyl content of the base adhesive
Recombinations with other crosslinking agents Recombination type and ratio
Construction conditions Temperature, humidity, construction time
Curing requirements Surface drying time, deep curing time, strength, elongation rate
Storage conditions Sealed, cool and dry, protected from light, moisture-proof
Acceptance indicators Surface drying time, deep curing, hardness, tensile strength, elongation rate
What should be mainly verified when using IOTA-31?


Surface drying time and deep curing time.


Hardness, tensile strength and elongation rate of the crosslinked silicone rubber.


Compatibility with the base adhesive, fillers and catalysts.


Crosslinking activity and stability after storage.


Extrudability and construction performance of the sealant.


Water resistance and aging resistance after curing.


Release and odor control of butanone oxime by-products.


Adhesion to the substrate (glass, metal, plastic, etc.).


Comparison of the recombination effect with IOTA-32 or other crosslinking agents.


Batch consistency and repeatability.


How to design the test before using IOTA-31?


Establish a current crosslinking agent benchmark, record the model, batch, addition amount and failure performance.


Unify test conditions: base adhesive, filler, catalyst, addition amount, construction environment.


Set candidate samples: current crosslinking agent, IOTA-31, different addition amount gradients.


Complete the full process test: mixing → construction → surface drying → deep curing → performance testing.


Evaluate actual results: surface drying time, deep curing, hardness, strength, elongation rate.


Test items Uniform requirements
Sample status New glue against new glue
Base glue and fillers Keep consistent
Catalyst type and dosage Keep consistent
Addition amount Set gradient according to application scenarios
Construction environment Same temperature and humidity
Measurement methods Table drying, deep curing, hardness, strength, elongation rate are consistent
Which situations are not suitable for directly using IOTA-31?


The hydroxyl content of the base glue is not confirmed, resulting in insufficient or excessive crosslinking density.


The surface of the filler is not treated, affecting the dispersion of the crosslinking agent and the uniformity of the reaction.


The type or dosage of the catalyst is not optimized, resulting in non-compliant curing speed.


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


There is a strict requirement for the odor of by-product dimethyl ketoxime, but odor assessment has not been conducted.


Only the type of base glue is known, without fillers, catalysts and construction conditions.


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


When switching from IOTA-32 or other ketoxime-based crosslinkers, the addition amount and catalyst system have not been re-adjusted.


What selection support can Ayoata provide?


As a "provider of the organic silicon全产业链 solutions"， Ayoata can assist in comparing the applicability of ketoxime-based crosslinkers in different base glue systems， filler types and construction conditions for IOTA-31.


For projects of room-temperature curing silicone rubber or neutral silicone sealant that need to balance table drying speed， deep curing and mechanical strength， before selection， the following information should be provided：


Base glue type and hydroxyl content.


Filler type and addition amount.


Catalyst type and dosage.


Target table drying time and deep curing time.


Target hardness， tensile strength and elongation rate.


Construction environment temperature and humidity.


Current crosslinking agent model and addition amount.


Failure manifestations and acceptance methods.


After receiving complete materials， it can be determined whether to prioritize testing IOTA-31 or continue using the corresponding IOTA-32 or other crosslinker routes.


Common misunderstandings


A four-functional group crosslinking agent is always better than a three-functional group one.
Four-functional groups can increase crosslinking density and strength， but may cause the product to become brittle and have a decreased elongation rate， depending on the product requirements.


The higher the TOS content， the faster the curing speed.
The TOS content needs to be matched with the hydroxyl content of the base glue and the catalyst system. Too high or too low will affect the crosslinking efficiency and storage stability.


The higher the addition amount， the better the crosslinking effect.
Excessive addition may result in excessive crosslinking density， product brittleness or surface stickiness， and the optimal amount needs to be determined through small-scale tests.


It can be directly added to the in-use system if it is compatible with the base glue.
It is still necessary to confirm the filler， catalyst， construction conditions and long-term stability.


The performance at 25℃ is the same， so it can be replaced in equal amounts.
Different chemical structures of crosslinkers may have different hydrolysis rates， crosslinking efficiency and compatibility.


Ketoxime-based crosslinkers have no odor problem.
IOTA-31 crosslinks with water to produce dimethyl ketoxime， and the construction environment and product odor requirements need to be evaluated.


IOTA-31 and IOTA-32 can be interchanged at will.
The TOS content of IOTA-31 (18-20%) is higher than that of IOTA-32 (9-12%)， and after replacement， the addition amount and catalyst system need to be re-adjusted， and the curing speed and mechanical strength need to be verified.


Recommended selection steps


Confirm the base glue type and hydroxyl content.


Confirm the filler type and addition amount.


Confirm the catalyst type and dosage.


Confirm the current crosslinking agent model and addition amount.


Select IOTA-31 or other crosslinkers based on the application scenario.


Set different addition amount gradients for small-scale tests.


Test table drying time， deep curing time and mechanical strength.


Verify the compatibility with the base glue， filler and catalyst.


Complete storage stability and aging resistance tests.


Evaluate the release of by-product dimethylketoxime and odor control. After conducting multiple batch verifications, determine the official usage plan.