prefácio
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O comitê responsável por este documento é o ISO/TC 256, Pigmentos, Dyes and increments.

ISO 18473 consists of the following parts under the general heading Functional pigments and increments for special applications:

— Papel 1: Nanometer calcium carbonate for sealant applications

— Papel 2: Nanoscale titanium dioxide for sunscreen applications

ISO 18473-1-2015 Pigmentos funcionais e cargas para fins especiais – Papel 1: carbonato de cálcio de tamanho nanométrico para aplicações de selantes

introduzir
Sealants are widely used to prevent air, gas or liquid infiltration into many industries, incluindo construção, automobiles and electronics. Increments are an important component of sealant formulations that reduce cost and improve rheological and mechanical properties. The content of increment agent varies widely and can be as high as 50% (mass fraction). A common additive in sealants is calcium carbonate (CaCO 3) because it is readily available in a variety of sizes and can be used as a rheological modifier, enhancer, and sunblock. Commercial calcium carbonate can be divided into heavy calcium carbonate (GCC) and precipitated calcium carbonate (PCC), with three crystal structures of calcite, aragonite and spheroid aragonite. It exists in various forms, such as cubic, spherical, spindle, fibrous and acicular. Calcium carbonate with calcite crystal structure and cubic or spherical form is most widely used in sealant applications.

Nanoscale calcium carbonate (NCC) provides improved performance and additional features for a variety of sealants, including thixotropy, flame retardant, and improved durability and recyclability, and has become a major ingredient in sealant formulations. Nanoscale calcium carbonate in powder form is now easy to manufacture, mainly through the precipitation route to control size and form. The importance of surface treatment for the use of NCC in sealants cannot be overstated. Natural calcium carbonate 3 is hydrophilic. Como resultado, it tends to clump in organic polymers and plasticizers. NCCS, in particular, tend to aggregate more easily due to their small size and large surface area. NCCS are surface treated to give them hydrophobicity and improve their dispersion in hydrophobic systems. The surface treatment also improves the compatibility of the polymer matrix, thus improving the interface adhesion between the increment agent and the polymer.

It was found that the particle size, área específica da superfície, mass fraction, morphology, valor do PH, magnesium content, valor de absorção de óleo, water content and other characteristics of the supplied nano-sized calcium carbonate affected the performance of the sealant mixed with these materials. Nanoparticles. The characteristics of NCCS that need to be detailed in relation to sealant performance arise from the following facts. Primeiro, agreements between customers and suppliers do not always cover all material characteristics that affect sealant performance and/or machinability, or they are interpreted differently by customers and suppliers. Segundo, nanomaterials are relatively new. Material properties may depend on the technique used to measure them. So,

Esta parte da ISO 18473 lists the properties, measurements and characteristics of nanoscale calcium carbonate and is intended to aid its acceptance and application in sealants.

1 Âmbito de aplicação
Esta parte da ISO 18473 specifies the requirements and corresponding test methods for powdered nano-sized calcium carbonate for surface treatments used in sealant applications.

2 Arquivos de referência normativa
All or part of the following documents are conventionally referenced in this document and are required for the application of this document. Para referências datadas, versões somente para citações se aplicam. Para citações sem data, uma nova versão do documento referenciado (incluindo quaisquer alterações) aplica-se.

ISO 787-2, General test methods for pigments and increments-Part 2: Determination of volatiles at 105 °C

ISO 787-5, General test methods for pigments and increments – Papel 5: Determination of oil absorption values

ISO 787-9, General test methods for pigments and increments-Part 9: Determination of the pH value of aqueous suspensions

ISO 3262-1, coating increments — Specification and test methods — Papel 1: Introduction and general test methods

ISO 3262-6, paint increments-specification and test methods-Part 6: Precipitated calcium carbonate

– ISO 9277, Determination of specific surface area of solids by gas adsorption – BET method

ISO 15528, Tintas, vernizes e matérias-primas para tintas e vernizes – Amostragem

ISO 18473-1-2015 Pigmentos funcionais e cargas para fins especiais – Papel 1: carbonato de cálcio de tamanho nanométrico para aplicações de selantes

3 Termos e definições
For the purposes of this part of ISO 18473, os seguintes termos e definições se aplicam.

3.1 Nanoscale

Os tamanhos variam de aproximadamente 1 nm para 100 nm

Nota de entrada 1: Attributes that are not extrapolated from a larger size are usually (but not limited to) displayed within this size range. For such attributes, the size limit is considered to be approximate.

Nota de entrada 2: The lower limit in this definition (approximately 1 nm) was introduced to avoid the designation of individual and small atomic groups as nanoobjects or nanostructured elements, which may imply that there is no lower limit.

3.2 Precipitate calcium carbonate

A synthetic calcium carbonate composed of triangular crystals (por exemplo., calcite) or diamond-shaped biconical crystals (por exemplo., aragonite)

Apenas a seção de informações padrão é pública. Para ver o conteúdo completo, you will need to purchase the standard through the official channels.