Pure Polyurethane Condom With Low-Modulus Adhesive Layers

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Solution Overview

Problem

Existing condoms made of natural rubber latex are limited by thickness and protein content, posing safety risks and poor flexibility, while polyurethane condoms lack ideal flexibility, burst properties, and strength.

Innovation Solution

A pure polyurethane condom with multiple layers, each having distinct properties, is prepared using resins with varying tensile modulus and adhesiveness, including a low-modulus adhesive layer, to enhance flexibility and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If natural rubber latex is used for condom manufacturing, then the basic contraception function is achieved, but the thickness cannot be reduced to 0.04 mm or less and protein content poses safety risks

Engineering Contradiction:

Improvecontraception functionVSAvoidprotein allergy risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite materials by combining polyurethane resin with adhesive layers to create a multi-layer structure. This composite approach eliminates protein content while maintaining contraception function, and enables thickness reduction to 0.04 mm or less through the inherent properties of polyurethane material.

Inventive Principle:

Principle #40Composite materials

2Volume of moving object

If polyurethane material is used to reduce thickness, then thickness can be reduced to provide realistic experience, but flexibility becomes poorer than natural rubber

Engineering Contradiction:

Improvecondom thicknessVSAvoidflexibility

Core Design Contradiction:

Volume of moving objectVSEase of operation

Solution Approach 1:

The patent creates a composite structure with multiple polyurethane layers having different properties. The base layer provides thinness and realism, while the adhesive layers with specific tensile modulus (2.5 N/mm² or lower) restore flexibility. This composite approach allows thickness reduction to 0.04 mm or less while maintaining or improving flexibility compared to single-layer polyurethane.

Inventive Principle:

Principle #40Composite materials

3Device complexity

If single polyurethane resin is used, then material simplicity is achieved, but optimal performance in flexibility, burst property, water resistance, and strength cannot be simultaneously obtained

Engineering Contradiction:

Improvematerial structureVSAvoidoverall performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the condom structure into multiple functional layers: a base polyurethane film layer and adhesive layers with different tensile modulus values. This segmentation allows each layer to contribute specific properties - the base layer provides structural integrity and thinness, while the adhesive layers with controlled tensile modulus (2.5 N/mm² or lower) provide flexibility and elongation. The segmented structure achieves optimal overall performance that cannot be obtained with single-layer polyurethane.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite materials by combining polyurethane resin with specially formulated adhesive layers. This composite structure integrates the advantages of different materials - polyurethane provides water resistance and strength, while the adhesive layers with low tensile modulus provide flexibility and elongation. The composite approach simultaneously achieves optimal flexibility, burst property, water resistance, and strength.

Inventive Principle:

Principle #40Composite materials

4Ease of operation

If adhesive layers with low tensile modulus are added to improve flexibility, then flexibility and elongation are enhanced, but the structure becomes more complex

Engineering Contradiction:

ImproveflexibilityVSAvoidlayer structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies local quality by placing adhesive layers with specific properties (tensile modulus of 2.5 N/mm² or lower) only at specific positions - between the base polyurethane layer and the outer surface. This localized application of specialized material provides flexibility enhancement exactly where needed, while the rest of the structure maintains its structural integrity. The adhesive layers occupy only the necessary space to provide the flexibility function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials to balance flexibility and structural integrity. The adhesive layers with low tensile modulus are formulated to provide maximum flexibility with minimal thickness, reducing the overall structural complexity. The composite structure allows flexibility enhancement through material selection rather than through adding excessive structural layers.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12458528B2Pure polyurethane condom having adhesive layer, and preparation method therefor

Publication Date: 2025.11.04 RECKITT BENCKISER HEALTH LTD

AI summary

Disclosed in the present disclosure are a pure polyurethane condom having an adhesive layer, and a method for preparing the condom. The pure polyurethane condom having an adhesive layer at least comprises: a first polyurethane film layer; a polyurethane adhesive layer on the first polyurethane film layer; and a second polyurethane film layer on the polyurethane adhesive layer, wherein the 100% tensile modulus of the polyurethane adhesive layer is 2.5 N/mm2 or lower, and the structures of the first polyurethane film layer and the second polyurethane film layer are different from that of the polyurethane adhesive layer.