Multistage Polymer for Humidity-Resistant Hair Styling
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Solution Overview
Problem
Existing hair styling compositions, particularly those containing polymers, face challenges in achieving optimal durability, resistance to high humidity, and viscosity control, with a need for improved formulations that enhance styled hair properties and manufacturing efficiency, including the development of free-flowing polymer powders and optimized liquid viscosity.
Innovation Solution
A multistage polymer comprising a soft polymer with a glass transition temperature of 40°C or lower and a hard polymer with a higher glass transition temperature, specifically formulated with certain monomer units and weight ratios, which maintains thermal transition temperatures consistently across varying humidity levels when exposed to water and dried at temperatures below 100°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer is used in hair styling composition to improve durability and humidity resistance, then the styled hair properties are enhanced, but the viscosity of the liquid composition increases
Solution Approach 1:
The polymer is synthesized in multiple stages with different monomer compositions. Stage 1 produces a soft polymer core with low Tg for flexibility and low viscosity contribution. Stage 2 adds a hard polymer shell with high Tg for durability and humidity resistance. This segmentation allows each stage to optimize different properties independently.
Solution Approach 2:
The invention creates a composite polymer structure combining soft and hard polymer segments with distinct glass transition temperatures. The soft segment (Tg ≤ 40°C) provides flexibility and low viscosity, while the hard segment (Tg > 40°C) provides durability and humidity resistance. The composite structure achieves both improved reliability and acceptable ease of operation.
2Ease of manufacture
If polymer powder is produced for addition to hair styling composition, then manufacturing flexibility is improved, but the powder flowability becomes problematic
Solution Approach 1:
The polymerization parameters are controlled to produce particles with specific physical properties. The multistage process creates particles with optimized size distribution, surface characteristics, and internal structure that enable free-flowing powder behavior. Particle size is controlled through monomer feed rates and initiator concentration, while surface properties are influenced by the hard polymer shell formation.
3Reliability
If high humidity resistance is achieved through polymer formulation, then styled hair maintains hold in humid conditions, but the polymer requires higher glass transition temperature
Solution Approach 1:
The polymer is divided into functional segments: a soft segment (Tg ≤ 40°C) that maintains flexibility and a hard segment (Tg > 40°C) that provides humidity resistance. The hard segment's higher Tg specifically addresses humidity resistance while the soft segment prevents excessive rigidity.
Solution Approach 2:
Different regions of the polymer structure have different Tg values tailored to specific functions. The hard polymer shell or segment with higher Tg is localized to provide humidity resistance where needed, while the soft core or segment with lower Tg provides overall flexibility. This local differentiation of quality allows simultaneous optimization of both properties.
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 multistage polymer effectively enhances the durability and humidity resistance of styled hair while ensuring the resulting hair styling compositions have improved viscosity and flow characteristics, leading to better hold and style retention.
Implementation Method 1
at least one soft polymer having glass transition temperature of 40°C or lower, and at least one hard polymer having glass transition temperature higher than 40°C
Implementation Method 2
the multistage polymer, after exposure to liquid water followed by drying at temperatures below 100°C, shows maximum thermal transition temperature in an atmosphere of 0% relative humidity that differs by 20°C or less from the maximum thermal transition temperature in an atmosphere of 75% relative humidity
Data Source
AI summary
There is provided a multistage polymer that comprises (a) at least one soft polymer having glass transition temperature of 40°C or lower, and (b) at least one hard polymer having glass transition temperature higher than 40°C, wherein the glass transition temperature of said hard polymer is at least 10°C higher than the glass transition temperature of said soft polymer, wherein the weight ratio of said hard polymer to said soft polymer is from 1.01:1 1 to 100:1, and wherein said multistage polymer, after exposure to liquid water followed by drying at temperatures below 100°C, shows maximum thermal transition temperature in an atmosphere of 0% relative humidity that differs by 20°C or less from the maximum thermal transition temperature in an atmosphere of 75% relative humidity. Also provided are an aqueous latex comprising such a multistage polymer, a composition comprising a powder comprising such a multistage polymer, a solution comprising such a multistage polymer, and a method of styling hair comprising applying such a multistage polymer to the hair.