Modified PBT Copolymer Polycarbonate Composite Impact Strength

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Solution Overview

Problem

Current polymer compositions face challenges in achieving a balance between high modulus, good ductility, impact strength, and melt flow characteristics, often resulting in brittle failure or processing difficulties due to filler incompatibility, which complicates molding operations and economic viability.

Innovation Solution

A composition comprising modified polybutylene terephthalate copolymers derived from polyethylene terephthalate, polycarbonate, impact modifiers, reinforcing fillers, and fibrillated fluoropolymers, which are melt blended and processed using specific ranges of components to achieve improved mechanical properties and heat deflection temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If filler is added to reinforce the polymer to obtain high modulus, then the modulus is improved, but the polymer becomes brittle and impact strength is lowered

Engineering Contradiction:

ImprovemodulusVSAvoidimpact strength

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent uses a composite material system combining polycarbonate, modified PBT copolymer, and fibrillated fluoropolymer to achieve both high modulus and good impact strength. The specific composite composition (30-70 wt% polycarbonate, 20-50 wt% modified PBT, 5-20 wt% fibrillated fluoropolymer) creates a synergistic effect where the fluoropolymer fibrils provide toughness while the polycarbonate-PBT matrix provides structural rigidity, resolving the contradiction between modulus and impact strength

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters by incorporating modified PBT copolymer with specific PET residue content (5-20 mol%) and controlling the molecular weight and composition of the fibrillated fluoropolymer. These parameter changes enable the material to achieve both high modulus (through rigid polycarbonate-PBT matrix) and good impact resistance (through fibrillar reinforcement and ductility)

Inventive Principle:

Principle #35Parameter changes

Solution Approach 3:

The patent applies local quality by creating a heterogeneous structure where fibrillated fluoropolymer is distributed throughout the polycarbonate-PBT matrix. The fibrils are formed in-situ during processing, creating localized reinforcement zones that provide impact resistance without compromising the overall structural rigidity of the matrix

Inventive Principle:

Principle #3Local quality

2Strength

If filler is added to reinforce the polymer, then the modulus is improved, but processing difficulties arise due to lack of compatibility

Engineering Contradiction:

ImprovemodulusVSAvoidprocessing

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The modified PBT copolymer acts as an intermediary or compatibilizer between the polycarbonate matrix and the fibrillated fluoropolymer reinforcement. The modified PBT contains PET residues that improve interfacial adhesion and compatibility, enabling better stress transfer and reducing processing difficulties associated with filler-polymer incompatibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a three-component composite system where polycarbonate provides the base matrix, modified PBT copolymer provides compatibility and interfacial adhesion, and fibrillated fluoropolymer provides reinforcement. This composite structure resolves processing difficulties by ensuring good interfacial bonding between components while maintaining high modulus properties

Inventive Principle:

Principle #40Composite materials

3Strength

If filler is added to improve mechanical properties, then the modulus and strength are improved, but molding and flow-related problems occur

Engineering Contradiction:

ImprovemodulusVSAvoidmolding speed

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent changes the rheological parameters by controlling the molecular weight and composition of the polycarbonate-PBT-fluoropolymer system. The modified PBT copolymer with specific composition (10-30 mol% PET residue) and the fibrillar morphology of the fluoropolymer create a composite with optimized melt flow characteristics, enabling high molding speeds while maintaining reinforced mechanical properties

Inventive Principle:

Principle #35Parameter changes

4Strength

If high modulus is achieved through filler, then the stiffness is improved, but ductility and impact resistance are compromised

Engineering Contradiction:

ImprovemodulusVSAvoidductility

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent creates localized ductile zones through the fibrillar structure of the fluoropolymer distributed within the rigid polycarbonate-PBT matrix. During impact, these localized fibrillar regions can deform and absorb energy through fibril pull-out and matrix deformation, maintaining ductility while the overall matrix structure provides high modulus

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses a composite material system where the fibrillated fluoropolymer reinforcement is embedded in a ductile polycarbonate-PBT matrix. This composite structure allows the material to exhibit both high modulus (from the reinforced structure) and good ductility (from the ductile matrix and fibrillar reinforcement mechanism)

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 solution provides a balanced mechanical property profile with enhanced Notched Izod impact strength and flexural modulus, allowing for efficient molding operations while conserving resources and reducing greenhouse gas emissions.

Implementation Method 1

compositions comprising a fibrillated fluoropolymer in a polycarbonate-polyester matrix

Methodology Applied

Scientific EffectFibrillation:

Implementation Method 2

modified polybutylene terephthalate copolymers that (1) are derived from polyethylene terephthalate component selected from the group consisting of polyethylene terephthalate and polyethylene terephthalate copolymers

Methodology Applied

Scientific EffectChemical transformation:

Implementation Method 3

Methodology Applied

Scientific EffectMelt blending:

Data Source

PatentEP2291454B1Polymer compositions, method of manufacture, and articles formed therefrom

Publication Date: 2016.03.23 SABIC GLOBAL TECHNOLOGIES BV

AI summary

A composition comprises, based on the total weight of the composition: from 10 to 80 wt. % of a modified polybutylene terephthalate copolymer that (1) is derived from polyethylene terephthalate component selected from the group consisting of polyethylene terephthalate and polyethylene terephthalate copolymers and (2) has at least one residue derived from the polyethylene terephthalate component; from 10 to 80 wt. % of a polycarbonate; from 0 to 20 wt. % of an impact modifier; from 1 to less than 25 wt. % of a reinforcing filler; from 0.1 to less than 2.5 wt. % of a fibrillated fluoropolymer; from 0 to 5 wt.% of an additive selected from the group consisting of antioxidants, mold release agents, colorants, quenchers, stabilizers, and combinations thereof. The composition has a heat deflection temperature of at least 110°C, measured in accordance with to ASTM D648 on 3.2 mm thick molded bars at 0.455 MPa.