Waterborne Polyurethane Condom Formulation for High Burst Volume
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Solution Overview
Problem
Existing waterborne polyurethane condoms have poor softness and burst volume, which limits their performance and user experience compared to natural latex condoms, while natural latex condoms pose safety risks for those with protein allergies.
Innovation Solution
A method involving repetitive dipping and drying of anionic waterborne polyurethane with specific drying conditions to create a polyurethane condom with a low modulus and high burst volume, achieved by using a formulation of macromolecular polyols and controlled drying processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If waterborne polyurethane condoms are made with conventional formulations and processes, then they achieve adequate strength and durability, but they exhibit poor softness and low burst volume (7-11 L) compared to latex products
Solution Approach 1:
The patent applies parameter changes by modifying the tensile modulus parameter of waterborne polyurethane from conventional high values to ≤2.0 MPa, and adjusting elongation at break to ≥650%. These parameter changes transform the material properties to achieve both high burst volume (≥12 L) and improved softness, directly resolving the technical contradiction between strength and softness.
Solution Approach 2:
The patent uses composite materials by formulating waterborne polyurethane with specific compositions including macromolecular polyols (60-85% of solid raw materials), small molecule polyols, chain extenders, and catalysts. This composite formulation creates a material that combines the safety advantages of polyurethane (no protein allergies) with enhanced mechanical properties achieving burst volume ≥12 L and softness comparable to latex.
2Object-generated harmful factors
If natural latex rubber is used to achieve soft texture and high burst volume, then consumer acceptance and comfort are improved, but safety risks arise for people with protein allergies
Solution Approach 1:
The patent converts the potential harm of polyurethane's conventional poor softness and low burst volume into benefits by systematically optimizing the formulation and processing parameters. The waterborne polyurethane formulation with macromolecular polyols (60-85% of solids) and controlled drying processes transforms the material into one that provides both safety for protein-allergic individuals and high burst volume (≥12 L), making the previously limiting characteristics into advantages.
3Length of moving object
If the thickness of natural latex rubber condoms is reduced to 0.04 mm or less, then comfort and fit are improved, but the material characteristics of natural latex make it difficult to achieve such thin dimensions
Solution Approach 1:
The patent applies parameter changes by optimizing the waterborne polyurethane formulation and processing parameters to enable production of condoms with thickness of 0.02-0.06 mm. The specific parameters including tensile modulus ≤2.0 MPa and elongation at break ≥650% allow the material to be manufactured at ultra-thin dimensions while maintaining adequate strength and burst volume ≥12 L, overcoming the manufacturing limitations of natural latex.
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 method results in a polyurethane condom with a thickness of 0.02-0.06 mm, 100% tensile modulus of ≤2.0 MPa, burst volume of ≥12 L, and burst pressure of ≥1 KPa, offering improved softness and safety without protein allergens.
Implementation Method 1
dipping into the waterborne polyurethane and then drying, and repeating the process of dipping into the waterborne polyurethane and then drying for N times so as to obtain a waterborne polyurethane film
Implementation Method 2
dipping into the waterborne polyurethane and then drying
Implementation Method 3
the duration of the drying for fixing and the duration of the drying for formation satisfy tform=90·Φ−1.8·(N+2)·tfix
Data Source
AI summary
The present invention provides a waterborne polyurethane condom having a high burst volume and a preparation method thereof. The method comprises the steps of: providing a waterborne polyurethane; dipping into the waterborne polyurethane and then drying, and repeating the process of dipping into the waterborne polyurethane and then drying for N times so as to obtain a waterborne polyurethane film; rolling up an end of the waterborne polyurethane film and then drying; dipping into a releasing agent, followed by drying, mold releasing, and electrical inspection to obtain a waterborne polyurethane condom; wherein N is equal to 1-5, the waterborne polyurethane is an anionic waterborne polyurethane, and the waterborne polyurethane has a 100% tensile modulus of less than or equal to 2.0 Mpa and an elongation at break of greater than or equal to 650%; the polyurethane condom prepared by the method has a burst volume of greater than 12 L, a burst pressure of greater than 1 KPa, and a 100% tensile modulus of less than or equal to 2.0 MPa.