Waterproof Loudspeaker Cones Using Composite Paper
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Solution Overview
Problem
Loudspeaker cones made of ordinary paper absorb water, increasing mass and reducing stiffness, which affects sound quality when exposed to water, and alternative materials like aluminum and plastic have disadvantages as loudspeaker components.
Innovation Solution
A loudspeaker component is made from a composition of wood pulp, primary hydrophobic fibers such as fibrillated acrylic fibers, stiffening fibers like glass fibers, and fluorocarbon, which is cured into paper to maintain stiffness and resistance to water penetration, with specific proportions and processing to ensure uniform material properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ordinary paper is used for loudspeaker cones, then manufacturing cost and ease of manufacture are improved, but water resistance and stiffness when wet deteriorate
Solution Approach 1:
The patent applies composite materials by combining wood pulp with hydrophobic fibers (such as polypropylene or polyester) and binding agents to create a paper composition that maintains the ease of manufacture of traditional paper while adding water resistance. The composite structure allows the hydrophobic fibers to repel water and the binding agents to hold the structure together when wet, resolving the contradiction between ease of manufacture and water resistance.
2Ease of manufacture
If ordinary paper is used for loudspeaker cones, then manufacturing cost is improved, but stiffness when wet and acoustic performance deteriorate
Solution Approach 1:
The composite paper composition incorporates stiffening agents and hydrophobic fibers that maintain structural integrity and stiffness when wet. The binding agents cross-link to form a rigid network that prevents the paper from becoming soft and losing stiffness upon water exposure, while still using cost-effective wood pulp as the base material.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the paper by controlling the composition ratios of wood pulp, hydrophobic fibers, and binding agents. By adjusting these parameters during manufacturing, the paper achieves optimal stiffness when wet while maintaining cost-effectiveness through controlled material proportions.
3Reliability
If water-resistant materials like aluminum or plastic are used, then water resistance is improved, but acoustic performance and suitability as loudspeaker components deteriorate
Solution Approach 1:
The patent creates a composite material that combines the water resistance properties of synthetic fibers with the acoustic properties of wood pulp. The porous structure of the paper composite allows for proper acoustic transmission while the hydrophobic fibers provide water resistance, avoiding the acoustic problems associated with solid materials like aluminum or plastic.
4Quantity of substance
If paper absorbs water, then water absorption increases, but mass increases and stiffness reduces, affecting sound quality
Solution Approach 1:
The patent converts the harmful effect of water absorption into a beneficial property by incorporating hydrophobic fibers that actively repel water. These fibers create a water-resistant barrier within the paper structure, preventing water from penetrating and causing mass increase and stiffness reduction. The hydrophobic fibers essentially convert the potential harm of water exposure into a protective mechanism.
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 composite material maintains stiffness and dimensional stability when wet, reduces wet rub defects, and provides resistance against water absorption and warping, achieving good acoustic performance and durability while being producible on existing equipment.
Implementation Method 1
primary hydrophobic fibers, which resist water penetration and absorption
Implementation Method 2
stiffening fibers that retain stiffness when wet
Implementation Method 3
fluorocarbon, which provides resistance against water penetration
Data Source
Figure 1
Figure 2A~2B
AI summary
A water-resistant composite paper, suitable for use as a loudspeaker component, is made from a composition including wood pulp, hydrophobic fibers, stiffening fibers that retain stiffness when wet, and fluorocarbon. In some examples, fibrillated acrylic fibers and glass fibers are used.