This specification covers highly pigmented primers that contain zinc dust as the major pigment component (minimum 65% by weight in the dry fi lm) and are defined by their ability to protect ferrous substrates.
The vehicle type may be inorganic (Type I) or organic (Type II).
Each primer type (I and II) is classified according to the level of exterior performance at a severe marine site.Laboratory performance criteria are also included.
This specification does not cover weldable preconstruction primers such as SSPC-Paint 30.
Zinc-rich coatings, both topcoated and untopcoated, have been used successfully in a wide variety of environmental zones. For a detailed breakdown of applicability of various types of zinc-rich coatings in different environmental zones, refer to SSPC-PS Guide 12.00. Consult the coating manufacturer for specifi c exposure recommendations (see Note 13.1).
This coating is intended for application by spray for use by itself or as a primer in a multi-coat system.
Primers meeting this specification are categorized according to vehicle type and performance level.
If no vehicle type is specified, either Type I, inorganic, or Type II, organic, is acceptable (see Section 2.3).
If no performance level is specified, Level 1 is assumed (see Section 2.5).
COMPOSITION: The coating described in this specification consists of zinc dust, functional additives, and an organic or inorganic binder with appropriate solvents.
VEHICLE TYPES
1) Type I-A, inorganic post-curing vehicles—water soluble, include materials such as alkali metal silicates, phosphates, and modifications thereof which must be subsequently cured by application of heat or a solution of a curing compound (or curing solution).
2) Type I-B, inorganic self-curing vehicles-waterreducible, include water soluble alkali metal silicates, quaternary ammonium silicates, phosphates, and modifications thereof. These coatings cure by a reaction among the zinc, silicate, steel substrate, and naturally occurring carbon dioxide during
and after evaporation of water from the coating.
3) Type I-C, inorganic self-curing vehicles—solvent reducible, include titanates, organic silicates, and polymeric modifications of these silicates. These systems are dependent upon moisture from the atmosphere to complete hydrolysis, forming the titanate- or polysilicate-zinc reaction product.
4) Type II, organic vehicles covered by this specification, may be chemically cured or may dry by solvent evaporation. Under certain conditions, heat may be used to facilitate or accelerate drying and curing.
COMPONENTS: These zinc dust primers may consist of one, two, or three components.
EXTERIOR PERFORMANCE: The primer shall be classifi ed as follows according to the minimum number of months of successful performance at a severe marine site(see Section 9.3):
• Level 1: 12 months
• Level 2: 30 months
