Pigment Dispersion-EN

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Dispersing Agents Lankem ® Expertise in surfactant technology

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Pigment Dispersion-EN

Transcript of Pigment Dispersion-EN

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Dispersing Agents

Lankem®

Expertise in surfactant technology

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Company Background

Lankem are a global supplier of speciality surfactants’ with expertise in all market sectors. Our strength lies in our technical backup to ensure that the customer gets the correct surfactant recommendation for each particular application. Each and every surfactant behaves in a unique way depending on whether you require high foam, low foam, good wetting, good detergency, particular surfactant properties or in the case of this guide a surfactant that offers good dispersing properties.

If you need to contact our technical department the email is [email protected]

Also for a full list of all commercially available products then please click “Product Range”. If you require specific products that are not listed in the guide then please contact our technical department with your specific product requirements.

Lankem are also able to offer a customer specific service of providing customer “own label” products, either as a re-brand or blend.

Pigment Dispersion Process

The process of producing pigment dispersions involves grinding the solid pigment agglomerates into primary particles and then stably and homogeneously distributing these throughout the liquid binder. If these stages are inefficient flocculation may occur causing colour change, sedimentation, gloss and changes in viscosity.

Step 1. Starting pigment agglomerates are tightly packed particles separated by air and moisture. This moisture and air is then replaced by the liquid binder in the wetting stage. To improve this stage wetting agents can be used.

Step 2. The pigment agglomerates are the separated by techniques such as grinding, ball milling, small media milling and high-speed dispersing. This process also reduces the size of the pigment particles into primary particles and disperses the pigments throughout the liquid binder.

Step 3.To prevent flocculation this dispersion must be stabilised by dispersants. Otherwise the pigment particles will attract to one another reforming the pigment agglomerate reducing colour strength and gloss.

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HINDRANCE

Steric Hindrance

The surfactant contains a pigment affinity group and a binder affinity group. The pigment affinity group adsorbs at the particle surface and the binder affinity group extends into the binder. If the protruding groups come into contact with one another cause a build up of osmotic pressure forcing the particles to separate.

Electrostatic repulsion

The pigment particles adsorb anions (-) which then attracts a second layer of cations (+). This electrical double layer maintains the dispersion as the charged particles repel one another. This system requires a polar liquid binder such as water.

ELECTROSTATIC REPLUSION

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k Functionality of the Dispersing Agent

The dispersing agent acts as both a wetting agent and a dispersing agent. Wetting is necessary to improve the speed at which the liquid replaces the air on the pigment surface. Thereafter the product needs to be stable to it’s essential that the additive has good dispersing properties. The dispersing characteristics can be defined by two principles : electrostatic repulsion and / or steric hindrance between the pigment particles. This detailed as follows:

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Application Sectors :

Aqueous Organic Pigment Dispersing agents

Both Lansperse DS200W and Lansperse DS80 are the main dispersing agents used in this application sector. DS200W is non-ionic in nature while the DS80 is classed as an anionic surfactant. Both products have a bulk hydrophobe which helps to offer excellent steric hindrance. The DS80 also has some electrostatic repulsion due to its anionic charge. Both products can be used by the formulator either singularly or in combination. Synergistic effects are sometimes observed for anionic / non-ionic blends. Both product are the new generation of APE free with low VOC levels.

Typical dosage levels will be between 1 - 5% on the pigment

Lansperse DS200W Datasheet MSDS

Lansperse DS80 Datasheet MSDS

Carbon Black Dispersing Agents

Due to the versatility of our Lansperse DS200W this product has found to be one of the best dispersing agents for carbon black available on the market. This product has excellent wetting and dispersing properties and due to its unique effect of lowering the viscosity of the system the formulator is able to increase the carbon black loadings within the formulation.

Typical dosage levels will be between 1 - 5% on black

Lansperse DS200W Datasheet MSDS

Dispersing agents for Pigment Masterbatches for Plastics

Pigment masterbatches are used in plastic formulations with the key requirement that the masterbatch is thermally stable at temperatures around 180°C. Both Lansperse PPD01 and Lansperse P35A can be used as dispersing agents for pigmented systems where the end polymer may be extruded and moulded.

Lansperse PPD01 Datasheet MSDS

Lansperse P35A Datasheet MSDS

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Dispersing agents for Inorganic Pigment and Fillers

Lansperse SPA has been specifically developed to work as the primary dispersing agent for inorganic systems such as fillers. In particular inorganics’ such as Kaolin and calcium carbonate can be disperse in aqueous medium using our Lansperse SPA

Typical dosage levels between 0.1 and 0.5% on weight of filler / pigment

Lansperse DIS145 is a very effective dispersing agent supplied in powder form. It’s main use can be seen as a dispersant of inorganic pigments and fillers within an aqueous medium. In particular this product is very effective in dispersing carbon blacks, zinc oxide, sulfur, kaolin, talc and calcium carbonate.

Typical dosage levels will be between 1 - 5% on weight of filler / pigment

Lansperse SPA Datasheet MSDS

Lansperse DIS145 Datasheet MSDS

Dispersing Agents for Solvents and UV

Traditional formulations based upon white spirit for example are being replaced with more modern liquid carriers that cannot contain water due to the nature of the end application. Some cartridge inks for example are low VOC and are using dispersing agents such as our Lansperse SUV to ensure good wetting and dispersing characteristics. The two main application areas for non-aqueous systems are Solvent Inks and UV Curable inks. The Lansperse SUV has found to be effective in these two industries because it needs to be hydrophobic in nature to be soluble while still providing good surfactant properties.

Typical dosage levels will be between 1 - 5% on pigment

Lansperse SUV Datasheet MSDS

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