Pre-Activated Paste Rheology Additive for Coatings

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Solution Overview

Problem

Existing rheology additives, such as polyamide powders and hydrogenated castor oil derivatives, require an activation phase involving high shear and heating, making them difficult and costly to implement, with issues of stability and sedimentation, and posing risks of dust and VOC emissions.

Innovation Solution

A pre-activated paste comprising fatty acid diamides and a liquid organic plasticizer, which is easily dispersible and eliminates the need for activation, reducing production time, energy consumption, and improving handling safety and reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyamide powders or hydrogenated castor oil derivatives are used as rheology additives, then thixotropic behavior and viscosity control are improved, but activation requiring high shear and heating is required which increases complexity and energy consumption

Engineering Contradiction:
Improvethixotropic behaviorVSAvoidactivation process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-activating the rheology additive during manufacturing to create a paste form that is ready for use. The fatty acid diamide is pre-dispersed in a liquid carrier (mineral oil, vegetable oil, or water) and pre-heated to activate its thixotropic properties before reaching the end user, eliminating the need for high-shear activation at the application site.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical state and composition parameters of the rheology additive by transforming it from a powder or derivative form into a paste form. This involves changing the carrier medium from requiring high-shear activation to using liquid carriers (mineral oil, vegetable oil, or water) that enable direct dispersion and eliminate the need for high-shear mixing and heating at the application site.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If polyamide powders are used, then viscosity adjustment is achieved, but dust formation and handling safety issues occur

Engineering Contradiction:
Improveviscosity adjustmentVSAvoiddust formation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter from powder to paste form. By incorporating the fatty acid diamide into a liquid carrier (mineral oil, vegetable oil, or water) to create a paste with specific viscosity ranges (50-5000 cP), the product eliminates dust formation while maintaining the ability to adjust viscosity in the final composition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a liquid carrier (mineral oil, vegetable oil, or water) as an intermediary medium. This carrier serves as a vehicle that suspends the fatty acid diamide particles, preventing them from becoming airborne dust while still allowing the additive to function effectively in adjusting the viscosity of the final composition.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If high speed shearing and heating are applied for activation, then optimal rheological properties are achieved, but production time and energy consumption increase

Engineering Contradiction:
Improverheological propertiesVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing the activation process during manufacturing rather than at the application site. The paste is pre-heated to temperatures between 40-80°C and pre-sheared to activate the thixotropic properties of the fatty acid diamide before distribution, eliminating the need for time-consuming high-shear activation and heating at the end user's facility.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent modifies the activation parameters by reducing both temperature and shear intensity requirements. Instead of requiring high-shear mixing and heating to 120°C, the pre-activated paste formulation achieves optimal rheological properties with minimal shear and heating at 40-80°C, significantly reducing energy consumption and processing time.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If mineral fillers like fumed silica or calcium carbonate are used, then viscosity increase is achieved, but stability and sedimentation problems occur over time

Engineering Contradiction:
Improveviscosity increaseVSAvoidstability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameter by replacing inorganic mineral fillers (fumed silica, calcium carbonate) with organic fatty acid diamides. This chemical substitution fundamentally alters the mechanism of viscosity increase from particle-packing physics to molecular interactions, eliminating sedimentation and stability problems associated with mineral fillers while maintaining effective viscosity control.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The pre-activated paste provides comparable rheological properties without the need for activation, offering improved handling, reduced VOC emissions, and enhanced safety, with no dust formation, and can be used in both solvent-based and solvent-free compositions, enhancing productivity and reliability.

Implementation Method 1

These additives confer on the composition in which they are incorporated a thixotropic behavior characterized by a marked shear thinning, that is to say a reduction in viscosity when the shear increases, then a recovery in viscosity depending on time (equivalent to an effect hysteresis).

Methodology Applied
Scientific EffectThixotropy: Thixotropy

Implementation Method 2

a marked shear thinning, that is to say a reduction in viscosity when the shear increases

Methodology Applied
Scientific EffectShear thinning: Shear Thinning

Data Source

PatentEP1935934B1Rheology additive in the form of a pre-activated paste
Publication Date: 2012.07.18 ARKEMA FRANCE SA
  • EP1935934B1 patent drawingFigure 1
  • EP1935934B1 patent drawingFigure 2
  • EP1935934B1 patent drawingFigure 3

AI summary

The invention relates to a rheology additive in the form of a pre-activated paste comprising: A) at least one fatty acid diamide, introduced in powder form, said powder optionally containing, in addition to the diamide, hydrogenated castor oil; B) at least one organic plasticizer, said plasticizer being liquid at room temperature. Also related are a specific process for preparing this rheology additive, a composition comprising said additive, a process for preparing said composition, and specific uses, and in particular specific coatings obtained from said additive.