Propylene-Alpha-Olefin Interpolymer Adhesive Composition

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Solution Overview

Problem

Existing polymer compositions for adhesives face challenges in balancing high cohesion with low viscosity, which is essential for achieving optimal adhesive performance.

Innovation Solution

A propylene/C4-C10 alpha-olefin interpolymer composition with specific properties, including a range of unsaturation, density, melt viscosity, and crystallization temperature, is developed, which can be combined with tackifiers and waxes to enhance adhesive properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polymer composition is designed for high cohesion, then adhesive strength is improved, but viscosity increases

Engineering Contradiction:

Improvecohesive strengthVSAvoidviscosity

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The patent applies parameter changes by precisely controlling the comonomer content (5-25 wt% C4-C10 alpha-olefin), unsaturation level (0.010-0.030% per mole of propylene), and molecular weight distribution to achieve the optimal balance between cohesive strength and viscosity. By adjusting these parameters within specific ranges, the composition attains both high strength and appropriate flow characteristics for adhesive applications.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If polymer composition is designed for low viscosity, then flow is improved, but cohesive strength decreases

Engineering Contradiction:

ImproveviscosityVSAvoidcohesive strength

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent employs composite material principles by creating an interpolymer system combining propylene with specific amounts of C4-C10 alpha-olefin comonomers. This composite structure at the molecular level provides both the low viscosity needed for flow and the cohesive strength required for adhesion, resolving the contradiction between these two properties through controlled compositional design.

Inventive Principle:

Principle #40Composite materials

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 composition achieves a balance of high cohesive strength and flow, improving the adhesive's performance by adjusting its viscosity and crystallization temperature, thereby enhancing its suitability for various applications.

Implementation Method 1

a melting temperature (Tm) from 45 °C to 85 °C

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

the composition has a crystallization temperature (Tc) from -15 °C to -2 °C

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Implementation Method 3

a melt viscosity, at 177°C, from 0.5 kg/m-s (500 cP) to 200 kg/m-s (200,000 cP)

Methodology Applied

Scientific EffectViscous flow:

Data Source

PatentEP3325569B1Compositions containing low molecular weight propylene-based polymers

Publication Date: 2021.08.25 DOW GLOBAL TECHNOLOGIES LLC

AI summary

The present disclosure provides a composition comprising: A) a propylene/C4-C10 alpha-olefin interpolymer; (i)) a total unsaturation per mole of propylene from 0.010% to 0.030%, (ii) a density from 0.855 g/cc to 0.890 g/cc, and (iii) a melt viscosity, at 177C, from 500 cP to 200,000 cP.