Titania-Pigmented Polyamide Production via Rotor-Stator Dispersion
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Solution Overview
Problem
Existing processes for producing titania-pigmented polyamides are unsatisfactory in terms of achieving finely and uniformly divided titanium dioxide particles with low abrasivity, which is crucial for delustering or coloring polyamides during further processing like spinning.
Innovation Solution
A process involving dispersing titanium dioxide pigments in a mixture of water and caprolactam using a specific apparatus with a disk-shaped rotor and radial openings, followed by polymerization to produce polyamides with improved properties, including a mean average particle size less than 1.2 μm, reducing abrasivity and enhancing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If titanium dioxide is added at the start of polymerization or via masterbatch, then the polyamide can be delustered or colored, but the titanium dioxide particles are not finely and uniformly divided, resulting in high abrasivity
Solution Approach 1:
The patent applies preliminary action by dispersing titanium dioxide in water before polymerization begins. The titanium dioxide is pre-dispersed in an aqueous medium and then introduced into the polymerization process, ensuring fine and uniform particle distribution in the final polyamide product, thereby reducing abrasivity
Solution Approach 2:
The patent uses water as an intermediary medium to disperse titanium dioxide particles uniformly. The aqueous dispersion acts as a carrier that facilitates even distribution of titanium dioxide throughout the polyamide matrix during polymerization, preventing particle aggregation and reducing abrasivity
2Quantity of substance
If titanium dioxide is kneaded into caprolactam and then with water, then the pigment is incorporated, but the process is complex and produces coarse particles requiring sedimentation
Solution Approach 1:
The patent extracts the titanium dioxide dispersion step from the complex multi-stage kneading process. Instead of kneading titanium dioxide into caprolactam and then with water, the method introduces pre-dispersed titanium dioxide in water directly into the polymerization process, simplifying the overall process while achieving uniform pigment incorporation
Solution Approach 2:
The patent applies preliminary action by pre-dispersing titanium dioxide in water before introducing it to the polymerization process. This preliminary dispersion step ensures uniform particle distribution without requiring complex subsequent kneading and sedimentation operations
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 process results in polyamides with titanium dioxide particles of smaller size and improved uniformity, reducing abrasivity and enhancing the delustering or coloring efficiency, as demonstrated by lower abrasion rates compared to traditional methods.
Implementation Method 1
dispersing titanium dioxide pigments in a starting mixture containing water and caprolactam by means of an apparatus, said apparatus comprising a dispersing chamber, a disk-shaped rotor disposed in said dispersing chamber, a stator which has radial openings and is disposed in conjunction with said rotor in the dispersing zone of said dispersing chamber
Implementation Method 2
a disk-shaped rotor disposed in said dispersing chamber, a stator which has radial openings and is disposed in conjunction with said rotor in the dispersing zone of said dispersing chamber
Implementation Method 3
polymerizing said product mixture to a polyamide containing titanium dioxide pigments
Data Source
AI summary
Disclosed is a method for producing a polyamide containing titanium dioxide pigments. Said method is characterized by the fact that titanium dioxide pigments are dispersed in an initial mixture containing water and caprolactam by means of a device comprising a dispersion chamber, a disk-shaped rotor that is disposed inside said dispersion chamber, a stator that is provided with radial openings, is arranged within the dispersion zone of the dispersion chamber, and is connected to the rotor, a substance inlet located on each side of the rotor, preferably with a respective axial duct section such that the two flows of substance are combined in the peripheral edge area of the rotor disk, and a product outlet which is placed on the outer edge of the dispersion zone of the dispersion chamber, by feeding the titanium dioxide pigments to the dispersion chamber through one of said substance inlets while feeding the initial mixture containing water and caprolactam to the dispersion chamber through the other of said substance inlets, whereby a product mixture containing water, caprolactam, and the used titanium dioxide pigment is obtained via the product outlet, and the product mixture is polymerized so as to obtain a polyamide containing titanium dioxide pigments. Also disclosed are polyamides obtained according to the inventive method and the use of such polyamides as a masterbatch.