Lubricating Resin Composition for Personal Care
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Solution Overview
Problem
Existing lubricating resin compositions for personal care products, such as razors, suffer from low compatibility between water-soluble and thermoplastic resins, leading to rapid loss of lubricity and durability issues under wet conditions, with high-molecular weight water-soluble resins causing sliminess and cobwebbing, and thermoplastic elastomers having low flexibility and roughness resistance.
Innovation Solution
A lubricating resin composition comprising a thermoplastic elastomer with durometer A hardness between 10 to 40, combined with a water-soluble polyethylene oxide and a water-absorbent modified polyalkylene oxide, where the water-absorbent modified polyalkylene oxide has a water absorption ability of 10 to 40 g/g, improving flexibility and durability while maintaining lubricity and roughness resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-soluble resin and thermoplastic resin are melt-mixed to form a desired member, then the member can be formed with initial lubricity, but the water-soluble resin scatters in blocks on the surface and drops off in repeated use, causing loss of lubricity
Solution Approach 1:
A compatibilizer is introduced as an intermediary substance between the water-soluble resin and thermoplastic resin. The compatibilizer has both hydrophilic groups that interact with the water-soluble resin and hydrophobic groups that interact with the thermoplastic resin, acting as a bridge to improve compatibility and prevent block scattering of the water-soluble resin on the surface.
Solution Approach 2:
The invention uses a composite material system consisting of thermoplastic resin, water-soluble resin, and compatibilizer. This composite approach allows the combination of materials with different properties (hydrophobic thermoplastic and hydrophilic water-soluble) while the compatibilizer ensures uniform distribution and prevents phase separation that would cause block scattering.
2Reliability
If high-molecular weight water-soluble resin is used to improve water-solubility and lubricity, then the water-soluble component flows out at one time under wet condition, but this causes the skin to become slimy and the compact to contract and harden in repeated use
Solution Approach 1:
The molecular weight of the water-soluble resin is controlled within a specific range (10,000 to 1,000,000) rather than using high-molecular weight resin. This parameter change allows sufficient water-solubility and lubricity while preventing excessive flow out that causes sliminess and subsequent hardening in repeated use.
Solution Approach 2:
The compatibilizer is used to create local compatibility zones where the water-soluble resin is uniformly distributed within the thermoplastic matrix. This prevents concentration of water-soluble resin in specific areas, ensuring controlled release rather than one-time flow out that causes sliminess.
3Duration of action of stationary object
If another resin is mixed with water-soluble resin to improve durability, then durability may be improved, but the compatibility between the resins is low
Solution Approach 1:
The compatibilizer serves as a mediator between the water-soluble resin and thermoplastic resin, improving their compatibility. The compatibilizer contains both hydrophilic and hydrophobic segments that can interact with both types of resin, ensuring uniform mixing and stable composition while maintaining improved durability.
4Reliability
If high-molecular weight water-soluble resin is used to improve lubricity, then better lubricity is achieved, but the melt viscosity becomes higher requiring raised processing temperature
Solution Approach 1:
The molecular weight of the water-soluble resin is optimized to a specific range (10,000 to 1,000,000) that provides sufficient lubricity while maintaining acceptable melt viscosity. This parameter optimization allows processing at normal temperatures without requiring excessive heat that would complicate the processing conditions.
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 composition maintains superior lubricity and deformation resistance under both wet and dry conditions, with a low swelling ratio and reduced sliminess, making it suitable for repeated use in personal care products like razors.
Implementation Method 1
a water-absorbent modified polyalkylene oxide, where the water-absorbent modified polyalkylene oxide has a water absorption ability of 10 to 40 g/g
Implementation Method 2
utilize elution of a water-soluble resin under a wet condition to give lubricity to each of the surfaces of the cartridge
Implementation Method 3
a composition obtained by combination of a thermoplastic elastomer and a water-soluble polyethylene oxide is used as a guard made of a material which can bend depending on the external form of the skin to be shaved
Data Source
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AI summary
The present invention provides a lubricating resin composition for personal care, wherein the composition comprises 100 parts by mass of a thermoplastic elastomer having durometer A hardness (HDA) of 10 to 40, 10 to 40 parts by mass of a water-soluble polyethylene oxide, and 20 to 60 parts by mass of a water-absorbent modified polyalkylene oxide, and wherein the composition not only maintains its superior lubricity and roughness-resistant property under a wet condition even in repeated use thereof, but also represents a low swelling ratio and no slimy feeling under a wet condition.