The IOTA M6040K is the "high adhesion" version of the M6020 series. It is also a two-component, 1:1 mixed addition-type liquid silicone rubber without two-stage vulcanization, with a VOC of less than 0.5%, meeting BfR, FDA, and RoHS requirements. The product description highlights its core difference in having a stronger bonding/adhesion capability to the substrate, making it suitable for scenarios such as overmolding, insert molding, or dual-color molding where a strong bond between silicone and plastic/metal is required. Product description, 9
Core differences compared to M6020
Comparison item M6040K series M6020 series
Comparison item M6040K series M6020 series
Core positioning免二段硫化 + 高咬合力免二段硫化通用型
Compliance certifications BfR， FDA， RoHS BfR， FDA， RoHS
VOC < 0.5% < 0.5%
Curing conditions 130℃/90s or 150℃/45s (2mm) 130℃/90s or 150℃/45s (2mm)
Application scenarios Overmolding， insert molding， dual-color molding Infant and children's care, food contact, sealing ring
Technical parameters Not provided Complete (hardness/strength/elongation/tensile strength)
Both have a highly similar base formula (both are two-stage vulcanization-free, with the same curing conditions, and the same compliance level). The only difference is that M6040K has optimized the formulation for substrate bonding. Product description However, current information does not provide specific technical parameters for M6040K (hardness grades, tensile strength, elongation, tear strength, viscosity, etc.), and it is necessary to obtain TDS from the supplier for confirmation.
What does "high adhesion" mean
The surface energy of liquid silicone rubber is low (approximately 20–24 dyn/cm)， and its physical/chemical bonding strength with plastic (PC， PA， PBT， etc.) or metal substrates is usually weak， which can lead to delamination and detachment during overmolding. Traditional solutions include：
Base coating (primer)：喷涂 silane coupling agent on the substrate surface to increase the surface energy to 35–40 dyn/cm；
Mechanical locking： Designing the substrate with inverted grooves， serrations， or sandblasting to increase the bonding area.
M6040K achieves direct chemical bonding with the substrate through formulation modification (possibly introducing functional groups such as vinyl， amino， etc.)， eliminating the need for a base coating and reducing production costs while improving yield.
However， note that "high adhesion" is a relative concept. The actual bonding strength depends on the substrate type， surface treatment， mold temperature， and injection molding process. It is recommended to obtain specific bonding strength data (such as peel strength N/mm) from the supplier and verify it on the actual substrate (such as PC， PA66， PBT， metal， etc.).
Selection logic with M3054/M6020
Application scenario Recommended model Reason
Application scenario Recommended model Reason
General sealing (no compliance requirements) M3055 Cost advantage， balanced mechanical performance
Long-term static sealing (high temperature/high pressure) M3054 Low compression permanent deformation， longer sealing life
Food/infant/medical compliant products M6020 Two-stage vulcanization-free， VOC < 0.5%， eliminates post-curing
Overmolding/insert molding/dual-color molding M6040K High adhesion， eliminates base coating， stronger bonding to substrate
Key verification items for overmolding
Bonding strength (peel strength)
The core selling point of M6040K， but the specific values are not provided. It is necessary to obtain test data from the supplier and verify the peel strength on the actual substrate (such as PC， PA66， PBT， metal， etc.).
Substrate compatibility
The bonding effects between different plastics (PC, PA, PBT, PP/PE, TPU) and silicone rubber vary greatly. It is necessary to confirm which substrates the M6040K has been optimized for.
Surface treatment requirements
Even with a high bite force formulation, some substrates may still require sandblasting, plasma treatment or primer application. It is necessary to confirm with the supplier whether additional surface treatment is required.
VOC and Compliance
If used for food contact or infant and child care, VOC, D4–D10 and migration levels must be verified in accordance with GB 4806.16-2025. Product Introduction
Solidification condition matching
The reference value given in the data is 2 mm thickness: 130℃/90 seconds or 150℃/45 seconds. The solidification conditions should cover the base material that may absorb heat during molding, and the mold temperature and solidification time need to be adjusted.
How to verify from samples to mass production
Request technical parameters
Request the complete TDS of M6040K from the supplier to confirm the hardness level, mechanical properties, viscosity and bonding strength data.
Material compatibility test
Carry out small-scale tests on the actual used base materials to verify the bonding strength (peel test), appearance (bubbles, flow marks) and dimensional accuracy.
Process window test
Test the bonding effect under different mold temperatures, injection pressure and solidification times to determine the optimal process window.
Compliance verification
If used for food/baby care/medical purposes, conduct VOC, migration amount and low molecular silicone oxide testing in accordance with GB 4806.16-2025.
Mass production trial run
After the small-scale test is successful, verify the injection equipment, stability of mixing ratio, demolding cycle and consistency of the finished product.
What information to prepare before inquiring from the supplier
Provide non-confidential application summary: base material type (PC/PA/PBT/metal, etc.), encapsulation structure (complete encapsulation/local encapsulation/embedding), target hardness, injection process, whether food/medical compliance is required, current bonding problems encountered and estimated purchase volume. If there are clear requirements for bonding strength, the test method and acceptance criteria should be stated.
FAQ
How to choose between M6040K and M6020?
If the product involves encapsulation molding, insert injection molding or two-color injection molding, and requires a firm bond between the silicone and the base material, choose M6040K; if it is a pure silicone part (such as a sealing ring, nipple), choose M6020 instead. Product Introduction
2. Is a primer completely unnecessary for high bite force?
The information is not clearly stated. Some high bite force formulations still require surface treatment of the substrate (such as sandblasting, plasma treatment) to achieve the best results. It is recommended to confirm the specific bonding requirements for the substrate with the supplier.
3. Where are the technical parameters of M6040K?
The current information does not provide them. You need to request the complete TDS from the supplier to confirm key indicators such as hardness level, tensile strength, elongation, tear strength, and viscosity.
4. Can it be used for food contact or infant and child care?
The information indicates compliance with BfR, FDA, and RoHS requirements. The product introduction requires actual product verification in accordance with GB 4806.16-2025 to confirm VOC, migration amount, and low-molecular silicone content.
5. Why must catalyst poisoning be avoided?
The platinum catalytic system may not cure or the surface may become sticky when in contact with substances such as sulfur, phosphorus, nitrogen, and organic tin. Important matters include checking the substrate, release agent, and pigment in advance.
6. Can the A/B components be mixed across batch numbers?
No. Only components A and B of the same batch number can be mixed and used together. Important matter