Direct Answer

IOTA LSR 3750 is a food-grade two-component addition-cure liquid silicone rubber specially designed for cookware applications with no secondary baking required. Main features include two-component 1:1 mixing ratio, excellent mold release, VOC below 0.35%, fast heat curing, and excellent mechanical properties. Typical applications include baby care, food contact, seals, and other injection-molded products. The series includes 3750-20 through 3750-70 hardness grades, with cured Shore hardness of 20, 30, 40, 50, 60, and 70; tensile strength of about 7–10 MPa; elongation of about 650%–340%; and tear strength of about 20–40 kN/m.

Note: the product features state VOC below 0.35%, while the technical data table states VOC ≤0.4%. For sample requests, the current batch technical data or the supplier’s confirmed value should be used. The curing time section only says “see curing time” and does not provide a specific temperature-time table; actual curing conditions should be obtained from the supplier or confirmed with the equipment and product thickness.

Selection should not rely only on “food grade,” “no secondary baking,” or “low VOC.” First confirm the specific cookware use and contact medium, product structure and thickness, mold and release method, A/B 1:1 metering and mixing, curing temperature and time, mechanical properties and hardness grade selection, and the regulatory compliance and migration testing required for food contact. This article does not equate “no secondary baking” with no post-treatment being needed for all thicknesses and structures, nor does it equate “food grade” or VOC data with final-product compliance. IOTA can provide liquid silicone rubber raw materials and corresponding product data; the company does not provide complete formulations or formulation development services.

1. First Ask What LSR 3750 Is Expected to Solve

The series is used for cookware, baby care, food contact, seals, and other injection-molded products. Different applications focus on different points: cookware on food-contact compliance, heat resistance, oil resistance, wash resistance, odor, and feel; baby care on safety compliance, soft feel, and durability; food contact on regulatory compliance, migration, and odor; seals on compression set, rebound, sealing force, and media resistance; other injection-molded products on flow, release, and molding efficiency. Selection should start with the final product, contact medium, service temperature, and regulatory requirements, not just “food grade” or “no secondary baking.”

2. What to Specify in an Inquiry or Sample Request

If the customer already has a test specification, obtain the original document first. When criteria are missing, confirm them with the project owner and test laboratory before making samples, so that both sides do not discover different interpretations of “pass” after testing.

3. Check Mixing/Metering and Curing Conditions Before Discussing No Secondary Baking

IOTA LSR 3750 uses a two-component 1:1 mixing ratio. In production, confirm metering accuracy, mixing uniformity, and workable time; metering deviation or poor mixing can affect curing, release, and mechanical properties.

The data only say “see curing time” and do not provide a specific temperature-time table. Therefore, sample-request and acceptance documents should not simply apply conditions from other series. Obtain the current batch curing recommendation from the supplier and confirm it with the thickest section, mold temperature, injection amount, and equipment efficiency. “No secondary baking” should be understood as the series reaching target properties under confirmed primary curing conditions; it does not mean that any thickness or equipment requires no post-treatment. Whether secondary heating or post-treatment is needed should be confirmed with the specific product and customer specification.

4. Evaluate Cookware Applications According to Contact Media and Service Conditions

Cookware silicone products may contact hot oil, detergents, high-temperature steam, food acids and bases, and repeated washing. The product data state food grade, fast heat curing, and excellent mechanical properties, but “food grade” is a product positioning description, not the same as having passed all food-contact regulations or specific migration limits. For food contact, obtain the corresponding regulatory compliance statements and necessary migration test reports, and evaluate against the customer restricted-substance list.

For seals, grip and sealing performance cannot be judged only by hardness or tensile strength; compression set, rebound, dimensional stability, media resistance, and actual assembled sealing force should also be evaluated. The 3750-20 to 3750-70 grades range from hardness 20 to 70. Grade selection should be confirmed with cookware structure, feel, assembly force, and service temperature, not just hardness level.

5. Typical Properties Are Conditional Data, Not Finished-Product Certification

Technical data: Component A viscosity about 280–380 (23°C, 10 s⁻¹), Component B about 250–350, and the mixture about 265–365; cured density about 1.10–1.14 g/cm³; 3750-20 to 3750-70 hardness 20/30/40/50/60/70, tensile strength 7/7/8/10/9/9 MPa, elongation 650%/600%/580%/500%/400%/340%, and tear strength 20/25/30/40/35/32 kN/m; VOC in the table is ≤0.4%. These are typical data under the corresponding conditions in the product data and should be understood together with product thickness, mold, curing, and test methods.

There is a wording difference between “below 0.35%” in the product features and “≤0.4%” in the technical data table. For sample requests and acceptance, use the current batch technical data or the supplier’s confirmed value; do not select the lower value as a commitment on your own. VOC values also cannot be directly equated with food-contact compliance or odor acceptance.

Baby care and food contact applications involve safety compliance; material feature descriptions alone cannot determine final-product compliance. The final product must also be evaluated with formulation, process, additives, and contact conditions.

6. Prepare Samples in This Order Before Sending

1. Obtain the customer’s service conditions, regulatory requirements, and acceptance criteria; confirm whether “no secondary baking,” VOC, food contact, baby care, and hardness grade requirements are targets or existing results.

2. Specify application, contact medium, product structure and thickest section, mold, A:B = 1:1 mixing/metering, curing temperature and time, post-treatment arrangement, and hardness grade selection.

3. Check the current IOTA LSR 3750 data and batch data, then have the user make representative samples and keep records of mixing, injection, curing, release, and post-treatment.

4. Arrange tests as agreed; keep sample identity, test conditions, observation photos, and evaluation results in the report. Before expanding use, confirm whether the samples represent actual workpieces.

IOTA/Anhui Iota Silicone Oil Co., Ltd. positions itself as a solution provider across the organosilicon industry chain and can provide liquid silicone rubber raw materials and corresponding product data. When communicating, provide the final product, contact medium, regulatory requirements, cookware service conditions, mold, and curing equipment together to facilitate candidate screening; the company does not provide complete formulations or formulation development services.

FAQ

1. Does no secondary baking mean no post-treatment is needed at all?

It should not be interpreted absolutely. The series can reach target properties under confirmed primary curing conditions, but whether thicker products, complex structures, or specific compliance requirements need secondary heating or post-treatment should be confirmed with the specific product and customer specification.

2. The data only say “see curing time”—can conditions from other series be used directly?

It is not recommended. Obtain the current batch curing recommendation from the supplier and confirm it with the thickest section, mold temperature, injection amount, and equipment efficiency.

3. Is VOC below 0.35% or ≤0.4%?

The product features state below 0.35%, while the technical data table states ≤0.4%; there is a wording difference. For sample requests and acceptance, use the current batch technical data or the supplier’s confirmed value; do not commit to the lower value on your own.

4. Does “food grade” mean the final product is food-contact compliant?

No. Food-contact compliance also requires corresponding regulatory compliance statements, migration testing, and customer restricted-substance evaluation; the “food grade” wording alone cannot determine final-product compliance.

5. How to choose between 3750-20 and 3750-70?

Select with cookware structure, feel, assembly force, sealing requirements, and service temperature, not hardness alone. Different hardness grades also differ in tensile strength, elongation, and tear strength and should be evaluated with the target product.

6. Is higher hardness better for cookware seals?

Not necessarily. Sealing performance also depends on compression set, rebound, dimensional stability, and media resistance; test with the specific structure and service conditions, not hardness alone.