Polyurethane Urea Resin Powder Flowability and Pigment Adhesion
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Solution Overview
Problem
The existing polyurethane resin powders for slush molding face issues with low odor, poor powder flowability, pigment slipping and aggregation, and reduced productivity due to the migration of plasticizers and the use of ketimine compounds, which affect the quality and comfort of automotive interior components.
Innovation Solution
A powdery polyurethane urea resin composition with thermoplastic polyurethane urea resin particles having irregular surfaces and a specific particle size distribution, produced through a method involving polymerization, coalescence, and the use of an alicyclic diamine, organic solvent, and surfactant, with controlled dicondensate content and additives to enhance flowability and pigment adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spherical polyurethane resin powder is produced by dispersion in aqueous medium using high shear disperser, then the resin powder can be used for slush molding, but fine particles and coarse particles are formed in small amounts causing poor powder flowability and pinholes in molded article surface
Solution Approach 1:
The invention changes the dispersion parameters by controlling the shear rate within a specific range (100-500 s⁻¹) and adjusting the solid content concentration (5-20%), which prevents the formation of both fine and coarse particles while maintaining good powder flowability and eliminating pinholes in molded articles
Solution Approach 2:
The invention uses a moderate shear rate that is neither too high nor too low, avoiding the excessive shear that creates fine particles and the insufficient shear that creates coarse particles, thereby achieving optimal particle size distribution
2Ease of manufacture
If colorant is dusted onto uncolored resin particle surfaces, then the resin can be colored, but pigment particles slip down or aggregate during stirring and mixing
Solution Approach 1:
The invention performs preliminary action by adding the colorant to the monool before polymerization, allowing the pigment to be incorporated into the resin matrix during the formation process, which prevents pigment slipping and aggregation that would occur with post-forming surface dusting
Solution Approach 2:
The invention merges the coloring step with the polymerization process by adding colorant to the monool mixture before reaction, so that pigment incorporation and resin formation occur simultaneously, ensuring uniform distribution and strong adhesion
3Ease of manufacture
If conventional polyurethane resins are used for powder molding, then the material can be molded, but the resins are high in cost and have environmental problems due to organic solvent synthesis
Solution Approach 1:
The invention replaces the chemical synthesis method using organic solvents with a physical dispersion method in aqueous medium, eliminating the need for harmful organic solvents while maintaining the moldability and performance of polyurethane resin powder
Solution Approach 2:
The invention uses water as an inert and environmentally friendly dispersion medium instead of organic solvents, creating a safe and eco-friendly production environment that eliminates harmful emissions while maintaining resin quality
4Ease of manufacture
If ketimine compound is used as extender in polyurethane resin, then the resin can be produced, but low odor property is impaired affecting vehicle compartment comfortableness
Solution Approach 1:
The invention changes the extender compound from ketimine to diamine, which fundamentally alters the chemical composition and eliminates the source of unpleasant odors (dicondensates of ketones) while maintaining the resin's processability and performance
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 solution results in a low-odor, high-flowability resin composition with improved pigment adhesion and reduced defects, enhancing the quality and productivity of slush molding processes for automotive interior components.
Implementation Method 1
an aqueous solution containing a surfactant
Implementation Method 2
an organic solvent having a dielectric constant of 5 to 25
Data Source
AI summary
Provided are: a powdered material for slush molding; and a manufacturing process therefor. The powdered material is less odorous, exhibits excellent powder fluidity, and does not suffer from troubles resulting from the sliding-down or agglomeration of a pigment even when the resin particles have been pigmented on the surfaces thereof. Thus, the powdered material ensures high productivity. The powdered material is a powdered polyurethane urea resin composition which comprises (D) a polyurethane urea resin that has a total content of bimolecular condensate of acetone, bimolecular condensate of methyl ethyl ketone, and bimolecular condensate of methyl isobutyl ketone of 1,000 ppm or less and (N) an additive, wherein the polyurethane urea resin (D) takes the form of thermoplastic polyurethane urea resin particles (P) that have a volume-mean particle diameter of 20 to 500 μm and that have protrusions and recesses on the surfaces. The powdered polyurethane urea resin composition is manufactured by a manufacturing process which includes a step of mixing (A) an isocyanato-terminated urethane prepolymer with (B) an alicyclic diamine and/or an aliphatic diamine in an aqueous medium by stirring to form the resin particles (P).