Silicate-Free Aqueous Cleaning Formulation for Medical Instruments
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Solution Overview
Problem
Existing enzyme-containing formulations for cleaning hard surfaces, particularly medical instruments, are corrosive to metals like copper, brass, and aluminum, and require stabilization due to high pH levels, which can lead to decomposition and environmental concerns related to silicate additives.
Innovation Solution
An aqueous formulation comprising proteolytic enzymes, anionic and non-ionic surfactants, corrosion inhibitors, multivalent aliphatic alcohols, complexing agents, and para-hydroxybenzoic acid or its esters, with a pH range of 9.5 to 12.5, providing improved enzyme stability, cleaning power, and material durability without silicates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If alkaline formulations are used to improve cleaning power, then cleaning efficacy is improved, but corrosiveness to metals increases
Solution Approach 1:
The patent introduces corrosion inhibitors as intermediary substances that mediate between the alkaline cleaning formulation and the metal surfaces. These inhibitors form protective films on metal surfaces, preventing direct contact between the corrosive alkaline environment and the metals, thereby maintaining high cleaning power while reducing corrosiveness to copper, brass, and aluminum.
Solution Approach 2:
The formulation employs a composite approach by combining multiple ingredients including alkaline cleaners, enzymes, surfactants, and corrosion inhibitors in specific proportions. This composite formulation achieves synergistic effects where the corrosion inhibitors protect metal surfaces while the alkaline components and enzymes provide powerful cleaning action, resolving the contradiction between cleaning efficacy and material safety.
2Reliability
If silicates are added to improve material durability, then corrosion protection is improved, but deposits and discoloration increase
Solution Approach 1:
The patent extracts or removes silicates from the formulation entirely, replacing them with alternative corrosion inhibitors that do not produce deposits or discoloration. This elimination of silicates while maintaining corrosion protection through other means resolves the contradiction between material durability and cleanliness of the cleaning process.
Solution Approach 2:
The formulation changes the chemical parameters by using different corrosion inhibitor substances with different properties than silicates. The alternative inhibitors provide corrosion protection through different mechanisms that do not involve deposit formation, thereby maintaining material durability without the harmful side effects of silicates.
3Productivity
If high pH is used to improve cleaning power, then cleaning efficacy is improved, but enzyme stability deteriorates
Solution Approach 1:
The patent applies beforehand cushioning by adding enzyme stabilizers to the formulation that preemptively protect enzymes from degradation in high pH conditions. These stabilizers create a protective environment for the enzymes, cushioning them against the harsh alkaline conditions while allowing the formulation to maintain high cleaning power through the alkaline environment.
Solution Approach 2:
Enzyme stabilizers act as intermediary substances that mediate between the high pH environment and the enzyme molecules. These stabilizers interact with the enzymes to protect them from alkaline degradation, allowing the formulation to utilize high pH for cleaning power while maintaining enzyme activity and stability through the protective intermediary effect.
4Reliability
If silicates are added for corrosion protection, then material durability is improved, but environmental compatibility worsens
Solution Approach 1:
The patent removes silicates from the formulation to eliminate their environmental drawbacks. By extracting this ingredient and replacing it with environmentally friendlier corrosion inhibitors, the formulation maintains corrosion protection and material durability while improving environmental compatibility and reducing harmful effects on the ecosystem.
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 formulation achieves enhanced enzyme stability, cleaning efficacy, and material durability, comparable to or exceeding silicate-containing products, while minimizing corrosiveness and environmental impact, as demonstrated by in vitro tests and corrosion tests.
Implementation Method 1
a) one or more proteolytic enzymes
Implementation Method 2
b) one or more anionic surfactants
Implementation Method 3
c) one or more non-ionic surfactants
Implementation Method 4
d) one or more corrosion inhibitors
Implementation Method 5
f) one or more complexing agents
Implementation Method 6
g) one or more of para-hydroxybenzoic acid and esters thereof
Data Source
Figure 1
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Figure 3a
AI summary
The invention relates to an aqueous formulation which comprises a)one or more proteolytic enzymes, b)one or more anionic surfactants, c)one or more non-ionic surfactants, d)one or more corrosion inhibitors, e)one or more multivalent aliphatic alcohols, f)one or more complexing agents, and g)one or more of para-hydroxybenzoic acid and esters thereof. The pH value of the formulation is in the range of from 9. to 12.5. The formulation is used in the mechanical cleaning of hard surfaces, in particular of medical instruments, and is preferablysilicate free.