Polychloroprene Latex Ion Control for Rubber-Asphalt Stability

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Solution Overview

Problem

Conventional rubber-asphalt compositions face challenges in low-temperature stability and film-forming properties, particularly when using polychloroprene latex, and require sophisticated production facilities and labor-intensive installation on irregular surfaces, leading to increased construction costs and fluctuating physical properties.

Innovation Solution

An anionic polychloroprene latex with controlled potassium and sodium ion contents (0.7-1.5 parts by mass for potassium and 0.2 parts by mass or less for sodium per 100 parts by mass of solid matter) is used, along with an emulsion polymerization process and a rubber-asphalt composition containing 10-40% polychloroprene latex and 60-90% anionic asphalt emulsion, utilizing a polyvalent metal salt coagulating agent to enhance low-temperature stability and film-forming properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a low-temperature stabilizer is added to polychloroprene latex to improve low-temperature stability, then low-temperature stability is improved, but film-forming property deteriorates

Engineering Contradiction:
Improvelow-temperature stabilityVSAvoidfilm-forming property
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the polychloroprene latex by controlling the ratio of potassium ions to sodium ions to be 5 or more, and specifically controlling sodium ion content to be 0.2 parts by mass or less per 100 parts by mass of solid matter. This parameter change improves low-temperature stability without requiring additional stabilizers, thereby avoiding film-forming property deterioration.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional rubber-asphalt composition is used for waterproofing irregular surfaces, then waterproofing function is achieved, but labor for installation increases

Engineering Contradiction:
Improvewaterproofing functionVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent produces a flexible waterproof sheet by drying the rubber-asphalt composition containing the optimized polychloroprene latex. This sheet can be easily applied to irregular surfaces, reducing installation labor and time while maintaining waterproofing function.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If rubber-asphalt composition with varying rubber content is used, then application is simplified, but physical properties fluctuate

Engineering Contradiction:
Improveapplication simplicityVSAvoidphysical property consistency
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent establishes specific parameter ranges for the polychloroprene latex (potassium ion content, sodium ion content, and their ratio) that ensure consistent physical properties. By controlling these parameters within specified ranges, the patent achieves both ease of application and consistency of physical properties.

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 controlled ion content polychloroprene latex improves low-temperature stability and film-forming properties of the rubber-asphalt composition, reducing construction costs and labor, while maintaining stability without the need for additional low-temperature stabilizers.

Implementation Method 1

as it is prepared by starting the emulsion polymerization

Methodology Applied
Scientific EffectEmulsion polymerization:

Implementation Method 2

utilizing a polyvalent metal salt coagulating agent

Methodology Applied
Scientific EffectCoagulation: Coagulation

Data Source

PatentUS9321937B2Polychloroprene latex, rubber-asphalt composition and utilization method thereof, sheet, and waterproof coating film
Publication Date: 2016.04.26 DENKA CO LTD

AI summary

Provided are a polychloroprene latex giving a rubber-asphalt composition superior in low-temperature stability and film-forming property on the material to be coated, a rubber-asphalt composition and a utilization method thereof, a sheet, and a waterproof coating film. The rubber-asphalt composition includes a major agent containing 10 to 40 mass % of the anionic polychloroprene latex comprising potassium ions in an amount of 0.7 to 1.5 parts by mass and sodium ions in an amount of controlled to be 0.2 part by mass or less with respect to 100 parts by mass of the solid matter and 60 to 90 mass % of an anionic asphalt emulsion; and a coagulating agent of an aqueous solution containing a polyvalent metal salt as the principal component.