EPDM Rubber Eraser Composition Eliminating PVC Toxicity
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Solution Overview
Problem
Existing erasers, such as those made from PVC, natural rubber, and SBR, face issues with toxicity, rapid hardening, and the need for vulcanization and low-molecular-weight plasticizers, which are environmentally harmful and affect their erasing properties and color.
Innovation Solution
A composition comprising EPDM rubber, a plasticizer like polyisobutylene, and calcium carbonate, which does not require a vulcanization process and uses high-molecular-weight plasticizers, providing excellent erasing properties, hardness, and color, thus replacing traditional PVC erasers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVC is used as eraser material, then erasing properties are good, but toxicity increases due to plasticizers and hydrogen chloride generation
Solution Approach 1:
The patent removes harmful substances (plasticizers and chlorine-containing compounds) from the eraser composition entirely, replacing them with non-toxic alternatives: EPDM rubber as the base polymer, high-molecular-weight plasticizers (molecular weight ≥ 1,000) for flexibility, and calcium carbonate as filler, thereby eliminating toxicity while preserving erasing functionality
Solution Approach 2:
The patent creates a composite material system combining EPDM rubber with high-molecular-weight plasticizers and calcium carbonate filler. This composite achieves the desired balance of flexibility, hardness, and erasing performance without the toxic components found in traditional PVC erasers
2Object-affected harmful factors
If natural rubber or butadiene is used to replace PVC, then toxicity is reduced, but hardness increases rapidly due to sulfur cross-linking and oxidation
Solution Approach 1:
The patent eliminates sulfur and other cross-linking agents from the composition, using EPDM rubber that does not require vulcanization. This prevents the rapid hardening and browning that occur with sulfur cross-linking and oxidation, maintaining stable physical properties over time
Solution Approach 2:
The patent changes the chemical composition parameters by selecting EPDM rubber with specific properties (diene content 0-10%, ethylene content 50% or more) and using high-molecular-weight plasticizers, which fundamentally alters the material's behavior to prevent rapid hardening while maintaining flexibility
3Ease of manufacture
If SBR is used as eraser material, then processing is simplified, but environmental harm increases due to styrene content and low-molecular-weight plasticizers
Solution Approach 1:
The patent removes styrene and low-molecular-weight plasticizers from the composition, replacing them with EPDM rubber and high-molecular-weight plasticizers (molecular weight ≥ 1,000). This eliminates the environmental harm associated with SBR while maintaining ease of processing through simple mixing and molding without vulcanization
Solution Approach 2:
The patent develops a composite material system using EPDM rubber combined with high-molecular-weight plasticizers and calcium carbonate filler. This composite provides both environmental friendliness and manufacturing simplicity, as the composition can be processed through conventional mixing and molding operations without requiring vulcanization or special handling
Data Source
AI summary
The present invention relates to an eco-friendly eraser using EPDM rubber, and more specifically, to an eraser composition containing EPDM (ethylene-propylene-diene monomer), a plasticizer, and calcium carbonate, and to an eco-friendly eraser containing the same. The present invention can provide an eco-friendly eraser that does not require a vulcanization process, does not use low-molecular-type plasticizers, and has excellent erasing properties, hardness, and color, and can replace PVC erasers.