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Crestamould® B21 Sealer

Crestamould® B21 Sealer is a brushable sealing laminating resin for polystyrene foam surfaces. When used with a chopped-strand mat, this sealer provides a styrene-resistant barrier between the polystyrene plug and styrenated tooling pastes. It has good adhesion to tooling pastes like Crestamould® T29. Crestamould® B21 sealer has a low styrene content, significantly reducing polystyrene surface erosion compared to traditional styrene-containing resins. The sealer can be used to laminate CSM to create a more structurally stable foundation for mold production.

Brand: Crestamould (13 products)

Polymer Name: Polyester (unspecified)

Chemical Family: Polyesters

End Uses: Foams

Technical Data Sheet

Enhanced TDS

Knowde-enriched technical product data sheet

Identification & Functionality

Chemical Family
Polyesters
Polymer Name
Polyester (unspecified)
Reinforcement Form
Chopped Strand Mat,
Roving
Composite Materials Functions
Resins, Binders & Matrix Materials
Technologies
Composite Materials
Product Families
Composite Materials — Polymers & Resins
Thermoset Resins

Features & Benefits

Materials Features
Excellent Seal Properties,
Good Adhesion,
Good Sealant Properties,
Low Styrene Content

Applications & Uses

Markets
Industrial
Applications
Industrial — Chemical & Industrial Manufacturing
Tooling & Moldmaking
Plastics & Elastomers End Uses
Foams
Application
  • Crestamould B21 sealer is suitable for use on a vast range of polystyrene grades but we recommend testing on your chosen grade before use, to ensure that it is suitable for your application.
  • If separation has occurred, redisperse by thoroughly mixing the material until homogeneous. Ensure the polystyrene surface is clean before application.
  • Apply by brush. A resin to glass ratio of 3:1 should be used and no more than 2 layers of 450g CSM at a time to reduce the exotherm and risk of degrading the polystyrene plug. It is important to avoid excess accumulation (>3mm thickness) of material on the substrate surface. Allow 1.5 - 2 hours between the application of the sealer resin and subsequent lamination. These general properties are based on an ambient temperature of 24°C.

Properties

Physical Form
Fiber,
Mat
Typical Properties in Liquid State
ValueUnitsTest Method / Conditions
Density1.28 - 1.35g/cm³-
Viscosity (6.0)¹1900 - 2400 mPas-
Viscosity (0.6)²7500 - 9500 mPas-
Gel Time³15 - 20 min-
Note

¹ - RV1 Cone and Plate at 6.0 s⁻¹ (25°C)
² - RV1 Cone and Plate at 0.6 s⁻¹ (25°C)

³ - Gel time measured with 100g mass with 2% medium reactivity MEKP catalyst.
⁴ - Shelf life is defined from date of manufacture when stored as recommended.

Packaging & Availability

Packaging Information

Crestamould® B21 Sealer is supplied in 25kg pails and 5kg tins.

Storage & Handling

Shelf Life
6 months⁴
Storage Conditions
  • Crestamold® B21 Sealer should be stored between 5°C - 25°C in the original, unopened container in a dry, well ventilated place. Protect from freezing and direct sunlight. Avoid contact with oxidizing agents. If stored outside of the recommended storage conditions shelf life will be significantly reduced.
  • Mixing : Before using thoroughly mix contents. Do not remove any Crestamold® B21 from container before mixing.