Thermoplastic Polymer String With Homogeneous Ester Additive

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Solution Overview

Problem

Current polymer strings for sports and musical instruments face challenges in achieving stable, thin diameters with optimal playing characteristics, as they tend to be stiff, lose tension quickly, and have compatibility issues with additives, leading to premature aging and environmental concerns.

Innovation Solution

A polymer string using thermoplastic materials with homogeneously distributed alkyl-benzyl esters of 1,2 dicarboxylic acids, where the alkyl chain has at least five carbon atoms, at concentrations between 0.1 to 5 percent by weight, allowing for improved physical and playing characteristics while reducing diameter and processing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If monofilament strings are used for tennis rackets, then control is improved when playing hard, but the string tends to lose tension quickly and feels dead

Engineering Contradiction:
ImprovecontrolVSAvoidtension retention
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs composite materials by combining thermoplastic polyester with thermoplastic polyester elastomer in specific ratios (4-50 weight parts elastomer per 100 weight parts polyester). This composite structure allows the string to maintain control characteristics while improving tension retention and elasticity, resolving the contradiction between control and tension retention.

Inventive Principle:
Principle #40Composite materials

2Strength

If string diameter is increased to improve durability, then strength is improved, but playing characteristics deteriorate and the string feels dead

Engineering Contradiction:
ImprovedurabilityVSAvoidplaying characteristics
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the chemical composition parameters of the string material by incorporating thermoplastic polyester elastomer alongside thermoplastic polyester. This parameter change allows the string to achieve adequate strength and durability while maintaining thinner diameters (1.2-1.4mm) that preserve playing characteristics and ball feel.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If PTFE particles are dispersed in the matrix to reduce adhesion, then friction resistance is improved, but delamination occurs and useful life span is shortened

Engineering Contradiction:
Improvefriction resistanceVSAvoiduseful life span
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent extracts the PTFE particles from the system and replaces them with a thermoplastic polyester elastomer matrix. This extraction eliminates the adhesion problems and delamination issues caused by PTFE while maintaining low friction characteristics, thereby improving both friction resistance and useful life span simultaneously.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If complex composite string construction is used to achieve desired characteristics, then playing characteristics are improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveplaying characteristicsVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple separate components into a single extrusion process. By combining thermoplastic polyester and thermoplastic polyester elastomer into one homogeneous composite material that can be extruded directly, the invention eliminates complex assembly steps, solvent applications, and multiple processing stages, thereby reducing manufacturing complexity while maintaining playing characteristics.

Inventive Principle:
Principle #5Merging (Combining)

5Ease of operation

If traditional additives are used to improve playing characteristics, then performance is improved, but toxicity and environmental impact increase

Engineering Contradiction:
Improveplaying characteristicsVSAvoidtoxicity
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the base material itself by incorporating thermoplastic polyester elastomer, which inherently provides the desired playing characteristics without requiring additional toxic additives. This parameter change in the material composition eliminates the need for harmful substances while maintaining performance.

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 solution results in a string with narrowed standard deviation of physical characteristics, enhanced tensile strength, and improved ball control, while reducing material and energy usage, waste, and environmental impact, with simpler processing and lower toxicity.

Implementation Method 1

in which at least one alkyl-benzyl ester of a 1,2 dicarboxylic acid of one of its derivates, is homogeneously distributed

Methodology Applied
Scientific EffectHomogeneous distribution:

Implementation Method 2

This string is produced in an extrusion process, starting from a molten mixture of a thermoplastic polyester with a thermoplastic polyester elastomer as the base material

Methodology Applied
Scientific EffectExtrusion: Extrusion

Data Source

PatentEP2159305B1Polymer string
Publication Date: 2016.02.17 LUXILON IND

AI summary

Polymer string mainly but not exclusively consisting of one or several polymers, characterised in that at least one polymer consists of a thermoplastic material in which at least one alkylbenzyl ester of a 1,2 dicarboxylic acid or one of its derivatives is distributed homogeneously, that the alkyl chain of the alkyl-benzyl ester or one of its derivative+es consists of at least five carbon atoms, and that it is used in a concentration between 0.1 to 5 percent by weight, better between 0.3 to 4 percent by weight, and even better between 0.3 to 1.2 percent by weight.