Energy savings plus mechanical reinforcement and rheology control

Low Slumping Waterborne Acrylic Sealant (A)

Adhesives Formulation

Applicable Type

Waterborne Adhesives

Applicable Base Polymer

Emulsions / Dispersions

Applicable Industrial Sectors

Buildings & constructions

Applicable Base Polymer Properties

Acrylic emulsion based sealants have taken over many of the applications where a higher movement capability is required than for polyvinyl acetate sealants. Acrylic sealants can also be used outdoors, whereas the polyvinyl acetate sealants have inferior exterior durability.

Acrylic emulsion polymers are ideally suited to the formulation of medium performance sealants. There is a significant variation in the types of base polymer emulsions that are available, and these emulsions are easy to formulate. This gives the formulator wide latitude for compounding to meet specific requirements. Sealants based on acrylic emulsions provide tough, elastic systems, with high adhesion and durability, and they are very environmentally friendly and easy to use.

Typical Formulation Ingredients

Ingredient

Parts by weight

Acrylic latex (Acronal 81D, BASF)

xxxx

Plasticizer (Plastilit 3060, BASF)

xxx

Pigment paste (Plastilit 3060 / Kronos 2056; 1:1, BASF / Kronos)

xxx

Surfactant (Lumiten N-OG, BASF)

xxx

Dispersing agent (Pigmentverteiler N, BASF)

xxxx

Defoamer (Lumiten E-L, BASF)

xxxx

Extender (Microtalc AT-1, Omya)

xxx

Extender (Omya BLP-3, Omya)

xxxx

Water

xxx

Rheological additive (Benaqua 1000, Elementis)

Rheological additive (Rheolate 425, Elementis)

Fumed silica

(Source: “Use of Elementis Rheological Additives in Acrylic Based Sealant”, Application Guide, Elementis Specialties, 2006)

Typical Properties

Properties

Slump, mm

Workability

xxxx

Water pick-up after 24 hrs, %

xxxx

Loss on drying after 3 days, %

xxxx

Processing

Resulting Properties

A broad product line with a wide range of properties can be developed by only varying the pigment-to-binder ratio. With high pigment-to-binder ratios, water based acrylic sealants are able to compete against the low cost polyvinyl acetate and vinyl acrylic sealants. On the other end of the formulation spectrum, low pigment-to-binder ratios provide competition to high performance sealants. In this way acrylics can compete against the polyurethane and silicone sealants meeting ASTM C 920. Typical formulation for standard acrylic latex sealants is given above.

Usually fumed silica is used as a rheological additive in acrylic based sealants. However, liquid rheological additives can also be used to achieve low slumping characteristics as shown in the formulations above.

Tips and Tricks

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