What baby and pet product brands should compare before approving a silicone material
“50 Shore A food-grade silicone” gives a supplier a starting point, but leaves much of the material specification undefined.
The phrase identifies a hardness target and an intended food-contact use. It does not identify the silicone grade, tear resistance, elongation, compression set, shrinkage, cure system, post-cure requirements, color package, test conditions, or finished-product validation plan.
That gap matters. A baby spoon, a suction bowl, a pet bowl, and a lick mat can all be made from silicone near the same nominal hardness, yet their structures ask the material to perform very different jobs. Selecting a grade from hardness alone can therefore produce a part that matches the number on the drawing but fails in the user’s hands.
The better approach is to treat Shore A hardness as one input in a product-specific material specification. A usable specification records the material identity, relevant properties, process conditions, and finished-product verification alongside that number.
What Shore A hardness tells you
Shore A hardness describes how an elastomer resists indentation under a defined measurement method. It is useful for comparing the relative softness or firmness of suitable rubber samples. It can also help a development team set an initial target for touch, bending, or structural support.
But hardness is not a durability score. It does not measure how the material resists tearing under a specified test, how far the rubber can stretch before breaking, how well a compressed feature recovers, or how a thin rib behaves after hundreds of bending cycles.
The test result also depends on sample preparation and measurement conditions. A reading taken on a standard test slab is not automatically the same as a reading taken on a thin spoon tip, a curved bowl wall, or a textured lick mat. Part thickness, local geometry, support beneath the test area, cure history, and conditioning can all affect what the measurement means in practice.
Record the hardness target together with the test method and the other properties the product needs.
Five variables hardness cannot replace
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| Variable | What it helps answer | Why Shore A cannot replace it |
|---|---|---|
| Tear strength | How a material resists tearing under a specified specimen and test method | Compounds at the same or similar hardness can use different formulations and show different tear behavior |
| Elongation at break | How far a standard specimen stretches before breaking | A high value does not by itself predict repeated-flex life or performance around a sharp corner |
| Compression set | How much deformation remains after compression and recovery | Useful when screening compressed features; it does not by itself predict suction or recovery after packaging |
| Cure and post-cure conditions | How the supplier prepared the specimen and developed the reported properties | Data obtained under different thermal histories may not be directly comparable |
| Linear shrinkage | The material’s reported dimensional change under specified conditions | Actual part shrinkage also depends on geometry, mold conditions, flow, demolding, and post-curing |
Wacker’s Solid and Liquid Silicone Rubber: Material and Processing Guidelines lists hardness alongside tensile strength, elongation, tear resistance, compression set, and cure information. Its product tables identify the figures as guidance rather than specification values. The guide also explains that tear-test methods can produce different results and that actual curing conditions depend on the material and part geometry. Record those conditions alongside the values being compared.Wacker material and processing guide.
The following examples are engineering considerations for planning design reviews and tests. They do not report measured performance of a particular product or define a complete safety test program.
Baby product example 1: A soft spoon still needs a stable structure
A baby feeding spoon may need a soft tip, a controlled entry depth, smooth edges, and enough flexibility to feel gentle. Those needs often lead teams to begin with a Shore A target.
The spoon, however, is not a uniform test slab. The tip may be thin while the handle is thicker. The transition between them may experience repeated bending. If the same material is used throughout, the geometry must create both a compliant tip and a handle that the caregiver or child can control.
Hardness alone cannot tell the team whether the neck will tear, whether the tip will fold too easily under food, or whether an insert will remain securely retained. The development sample should therefore be evaluated for bending, pull resistance where relevant, edge condition, repeated use, cleaning, and performance after the intended heat exposure. Testing multiple thickness-and-grade combinations is more informative than asking for one hardness number and treating it as final.
Baby product example 2: A suction bowl needs more than softness
For a suction bowl, a flexible sealing edge may help the suction feature conform to a smooth surface. Yet making the entire product softer can reduce wall support, make scooping harder, or allow the child to deform and lift the bowl more easily.
Recovery after deformation also deserves a separate check. A suction feature that remains distorted after long packaging, stacking, or repeated use may perform differently even when its initial hardness is unchanged. The seal geometry, suction-cup diameter and depth, wall thickness, side loads, surface texture, cleanliness, and product weight all contribute to the result. A compression-set figure is only a screening input here: packaging distortion can involve bending and other loads that the standard compression test does not reproduce.
The appropriate validation is functional: test the finished bowl on the surfaces the brand plans to name, after realistic packaging and cleaning cycles. A statement such as “lower hardness improves suction” should be treated as a design hypothesis, not a universal rule. The material and the suction structure must be developed together.
Pet product example 1: A bowl must balance flexibility and shape retention
A silicone pet bowl needs enough structural stability to hold food and resist movement during feeding. It may also need flexibility for handling, packing, or a non-slip base. A harder compound may help one geometry retain its shape, but it does not automatically provide better tear resistance or a longer service life.
The rim, base, wall thickness, overall diameter, filled weight, and center of gravity all influence stability. A thin wall made from a firmer material can behave differently from a thicker wall made from a softer grade. Scratching, repeated washing, folding, and long-term storage add other failure modes that a durometer value does not capture.
Brands should evaluate tipping, sliding, deformation, cleaning, and recovery after packaging using the intended production material. If the product may be grabbed or lifted by the rim, that use should be included in the durability plan. A feeding bowl should not be described as chew-resistant unless its structure and validation are designed for that claim.
Pet product example 2: Thin ribs can fail while the data sheet looks strong
Lick mats and slow-feeder bowls create function through geometry: raised dots, narrow ribs, channels, undercuts, and thin textured areas. These features are intended to distribute food or make it less directly accessible. They also need review for local stress and demolding difficulty.
A nominal hardness cannot show whether the root of a tall rib is too thin, whether a sharp internal corner will start a tear, or whether a pet can grip and pull an exposed edge. Tear strength is relevant, but the finished geometry, molding quality, trimming, and repeated flexing remain critical.
Validation should include realistic foods, cleaning access, bending, pulling, repeated handling, and inspection of the feature roots. A design with larger corner radii and better thickness transitions may outperform a harder compound used in a weak geometry. Material selection and design-for-manufacturing review should happen before the mold locks those details in place.
See our silicone pet tableware range for product formats to discuss in a development brief.
A supplier data example: why the conditions matter
Two public Shin-Etsu LIMS product pages illustrate why a buyer should read across the full row instead of selecting the highest hardness or highest single property.
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| Supplier-reported item | KEG-2000-50-A/B | KEG-2003H-70-A/B |
|---|---|---|
| Primary cure | 120°C × 10 min | 150°C × 5 min |
| Listed post-cure | 150°C × 1 h | No post-cure listed; marketed as a no-post-cure grade |
| Hardness, Durometer A | 51 | 69 |
| Tensile strength | 12.7 MPa | 9.1 MPa |
| Elongation at break | 670% | 490% |
| Tear strength, crescent specimen | 38 kN/m | 46 kN/m |
| Compression set | 11% [1] | 28% [2] |
[1] Separate compression-set specimen preparation: 120°C × 15 min, then 200°C × 4 h. Test exposure: 175°C × 22 h.
[2] Separate compression-set specimen preparation: 150°C × 15 min. Test exposure: 120°C × 22 h.
The harder grade shows the higher reported tear value in this table, while the softer grade shows the higher reported tensile strength and elongation. Neither grade is better overall on that basis. They have different hardnesses, positioning, cure histories, and compression-set test conditions. The 11% and 28% values must not be ranked as if they came from the same test exposure. This is a reading example, not a controlled experiment isolating the effect of hardness. The supplier labels the values as non-specified data, and the intended product structure is not part of the comparison.
Use this table to form questions and design trials. It does not establish that either grade is suitable for a specific baby or pet product. See the original KEG-2000-50-A/B product page and KEG-2003H-70-A/B product page.
How to build a better silicone material specification
A practical purchasing specification should connect the material to the product and process. At minimum, review:
- Manufacturer and exact grade: not only “LSR,” “HCR,” or “food-grade silicone.”
- Cure system and mixing requirements: including A/B ratio or curing-agent controls where applicable.
- Hardness target and tolerance: plus a defined test method, specimen, thickness, conditioning, reading time, and measurement location. If the finished part cannot meet the chosen method’s specimen requirements, agree on a suitable test specimen and evaluate the part’s function separately.
- Function-critical properties: such as tear strength, tensile strength, elongation, compression set, or other values justified by the design.
- Color and additives: identify the color system and any changes that may affect cure, performance, or food-contact evidence.
- Primary cure and post-cure: specify the approved process or the method for establishing it; do not copy another grade’s temperature and time.
- Finished-product tests: connect the material requirement to suction, bending, pulling, cleaning, dimensional recovery, or other real functions.
- Food-contact and market documents: confirm the exact grade, formulation, color, intended use, applicable requirement, and remaining finished-article responsibilities.
- Traceability and change control: record raw-material batch, production lot, TDS version, and notification requirements for material or process changes.
Momentive’s Addisil Industrial 10×0 E TDS provides a useful boundary: it reports different typical mechanical properties across a hardness series under specified vulcanization and post-cure conditions, states that the averages should not be used to develop product specifications, and assigns finished-product compliance assessment to the user’s specific manufacturing process. Momentive Addisil Industrial 10×0 E TDS.
Validate the finished product
Once candidate grades are selected, use samples that are close to production in material, color, geometry, and process. Record the grade, batch, color system, cure and post-cure conditions, mold version, and test setup. A reference sample without those records may be difficult to reproduce.
Then test the functions that matter. For the four examples in this article, that means spoon bending and connection durability; bowl suction and recovery; pet-bowl stability and cleaning; and lick-mat or slow-feeder feature strength and food removal. Include packaging and repeated-use conditions where they can change the result.
If the grade, color package, production location, cure process, geometry, or post-cure changes, review the risk before assuming the previous approval still applies.
Start with the job, then verify the grade
Shore A hardness is useful because it gives development teams a shared language for softness and firmness. Problems begin when that one number is asked to stand in for the entire material, manufacturing process, and finished product.
Define what the product must do. Identify the structures most likely to bend, seal, compress, or tear. Select candidate grades using complete supplier data. Then verify them in the actual design and intended process.
Before approving a mold or production material, review whether the specification connects hardness to function-critical properties, processing conditions, finished-product tests, and change control. That review makes unresolved material and test requirements visible before the team commits to tooling and production.
Planning a silicone baby or pet product? Share your product brief, target market, and intended use with us.