Carpet Coating Binder Composition for Wet Strength Retention

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Solution Overview

Problem

Carpet coatings based on vinyl acetate-ethylene copolymers face challenges in maintaining mechanical strength after exposure to water, leading to premature breakage and cracking due to high porosity and capillary water absorption, which affects cohesion and adhesion.

Innovation Solution

Incorporating an aqueous dispersion of vinyl acetate-ethylene copolymer with polyethyleneimine as a binder in carpet coating compositions, optimizing the formulation and application parameters to enhance mechanical strength without the need for copolymerization or special stabilizer systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If vinyl acetate-ethylene copolymer is used as binder in carpet coating compositions, then good mechanical properties in fully finished carpet are achieved, but mechanical strength deteriorates after storage in water due to high porosity and capillary water absorption

Engineering Contradiction:
Improvemechanical strengthVSAvoidwet strength
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the binder by incorporating polyethyleneimine (PEI) at concentrations of 0.1-10% by weight based on dry binder content. This modifies the molecular structure and intermolecular forces within the coating, reducing capillary water absorption and preventing the collapse in mechanical properties that occurs with conventional vinyl acetate-ethylene copolymers when exposed to moisture.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite binder system by combining vinyl acetate-ethylene copolymer with polyethyleneimine. This composite material leverages the good mechanical properties of the copolymer while the PEI component provides resistance to water absorption and maintains strength in wet conditions, effectively resolving the contradiction between dry mechanical strength and wet reliability.

Inventive Principle:
Principle #40Composite materials

2Productivity

If foam application of carpet coating composition is used, then application efficiency is improved, but porosity and pore size distribution increase leading to high capillary water absorption

Engineering Contradiction:
Improveapplication efficiencyVSAvoidcapillary water absorption
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical parameters of the coating composition by adding polyethyleneimine, which changes the surface energy and capillary pressure characteristics of the dried coating. This reduces the driving force for capillary water absorption even when the porous structure remains, allowing foam application to maintain its productivity benefits while mitigating the harmful effect of water absorption.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If polyethyleneimine is added to carpet coating composition, then wet mechanical properties are improved, but formulation complexity increases

Engineering Contradiction:
Improvewet mechanical propertiesVSAvoidformulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces polyethyleneimine as a straightforward compositional parameter change with a specified concentration range (0.1-10% by weight). This single parameter modification provides significant improvement in wet mechanical properties without requiring complex processing equipment or multi-step formulation procedures, thus achieving high reliability with minimal increase in formulation complexity.

Inventive Principle:
Principle #35Parameter changes

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 use of polyethyleneimine in carpet coating compositions significantly improves the wet mechanical properties, including separation strength and knob pull-out force, even after water exposure, by enhancing cohesion and adhesion without compromising dry performance.

Implementation Method 1

The use of polyethyleneimine in carpet coating compositions significantly improves the wet mechanical properties, including separation strength and knob pull-out force, even after water exposure, by enhancing cohesion and adhesion

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

The use of polyethyleneimine in carpet coating compositions significantly improves the wet mechanical properties, including separation strength and knob pull-out force, even after water exposure, by enhancing cohesion and adhesion

Methodology Applied
Scientific EffectCohesion: Cohesion

Implementation Method 3

In the case of high porosity and a wide pore size distribution resulting from the foam application of the carpet coating composition, the capillary water absorption of the coating composition is also high

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3380664B1Binder for carpet coating compositions
Publication Date: 2019.04.24 WACKER CHEMIE AG

AI summary

The object of the invention is the use of an aqueous dispersion of a vinylacetate-ethylene-copolymer and of at least one polyethylene imine as a binder in a carpet coating composition for the production of carpets.