Crosslinked Hollow Particle Shells That Resist Collapse in Molding
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Solution Overview
Problem
Existing hollow resin particles are prone to collapse under shear or pressure during biaxial kneading or injection molding, and their void ratio decreases due to deformation, with fine through holes compromising their structural integrity.
Innovation Solution
A method involving suspension polymerization, where a first polymerizable monomer with a high crosslinkable monomer content is used, followed by adding a hydrophilic second polymerizable monomer at a specific polymerization conversion rate, forming a dense and strong shell through accelerated polymerization reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the void ratio of hollow particles is increased, then weight reduction and heat insulation effects are improved, but the shell thickness is decreased and the particles easily collapse
Solution Approach 1:
The patent uses a composite shell structure made from crosslinkable monomer units and non-crosslinkable monomer units. The crosslinkable monomer units form a crosslinked network that provides high strength and collapse resistance, while the non-crosslinkable monomer units contribute to the overall structure without forming crosslinks. This composite approach allows the shell to maintain high strength even with reduced thickness, enabling high void ratio hollow particles that resist collapse during processing.
2Weight of moving object
If the void ratio of hollow particles is increased, then weight reduction and heat insulation effects are improved, but the particles are more likely to collapse under shear or pressure
Solution Approach 1:
The patent changes the chemical and physical parameters of the shell material by controlling the ratio and types of crosslinkable and non-crosslinkable monomers. By adjusting the crosslinking density and shell composition, the patent optimizes the balance between void ratio and collapse resistance. The crosslinked structure provides high reliability and collapse resistance even when the shell is thin, allowing the hollow particles to withstand shear and pressure during biaxial kneading and injection molding.
3Strength
If a crosslinkable monomer is used to form the shell, then the shell strength is improved, but the polymerization reaction may become uncontrollable and cause resin aggregation
Solution Approach 1:
The patent uses a combination of crosslinkable and non-crosslinkable monomers, where the crosslinkable monomers provide the necessary strength through partial crosslinking. The non-crosslinkable monomers act as spacers that limit excessive crosslinking and aggregation. This partial action approach ensures that the shell has sufficient strength while maintaining controllable polymerization and uniform particle formation without resin aggregation.
4Weight of moving object
If the shell thickness is decreased to increase void ratio, then weight reduction effect is improved, but the structural integrity is compromised
Solution Approach 1:
The patent employs a composite shell structure where crosslinkable monomer units form a crosslinked network that provides exceptional strength-to-thickness ratio. This crosslinked composite structure maintains structural integrity even when the shell is very thin, enabling high void ratio hollow particles that do not compromise structural stability during processing and application.
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
Produces hollow particles with a high void ratio that are less likely to collapse, maintaining structural integrity even under pressure and shear, and preventing resin intrusion during molding.
Implementation Method 1
a mixture liquid containing a polymerizable monomer and a hydrocarbon solvent is prepared; suspending the mixture liquid to prepare a suspension in which droplets of a monomer composition containing the polymerizable monomer and the hydrocarbon solvent are dispersed in the aqueous medium, and then subjecting the suspension to a polymerization reaction
Data Source
AI summary
A method for producing hollow particles, the method comprising: preparing a mixture liquid containing a first polymerizable monomer, a hydrocarbon solvent, a dispersion stabilizer and an aqueous medium, suspending the mixture liquid to prepare a suspension in which droplets of a monomer composition containing the first polymerizable monomer and the hydrocarbon solvent are dispersed in the aqueous medium, and subjecting the suspension to a polymerization reaction, wherein the mixture liquid contains a crosslinkable monomer as the first polymerizable monomer in an amount of 75 to 100 parts by mass per 100 parts by mass of the first polymerizable monomer, and wherein, during the polymerization reaction, when a polymerization conversion rate of the first polymerizable monomer reaches 93% by mass or more, a second polymerizable monomer having a solubility of 0.3 g/L or more in distilled water at 20° C., is added to the suspension and further subjected to the polymerization reaction.