Double-Coated Paper Cup Base Paper for Sealability and Recycling

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Solution Overview

Problem

Existing base papers for paper cups lack recyclability and biodegradability while failing to maintain water resistance, oil resistance, heat sealability, and block resistance, leading to manufacturing difficulties and environmental issues.

Innovation Solution

A double-coating layer is applied to a basic paper, comprising a first coating layer with a resin having a low glass transition temperature for heat sealability and a second coating layer with a higher glass transition temperature for block resistance, along with defoamers and silica to prevent bubbling and ensure uniform application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a base paper is coated with polyethylene (PE) to ensure water resistance and heat sealability, then the paper cup manufacturing process is optimized, but the recyclability and biodegradability are compromised

Engineering Contradiction:
Improvewater resistance and heat sealabilityVSAvoidnon-degradability and recycling difficulty
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the coating material from polyethylene to a specific copolymer resin with defined glass transition temperatures and molecular weight parameters. This allows the coating to maintain functional properties (water resistance, heat sealability) while improving environmental compatibility through controlled degradation behavior.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite coating material consisting of specific copolymer resins with complementary properties - one resin providing heat sealability and another providing block resistance. This composite approach allows simultaneous achievement of multiple functional requirements while maintaining eco-friendly characteristics.

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If a base paper is coated with polylactic acid (PLA) to improve biodegradability, then environmental friendliness is enhanced, but the heat sealability and water resistance are insufficient

Engineering Contradiction:
ImprovebiodegradabilityVSAvoidheat sealability and water resistance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent employs a composite coating system using two different copolymer resins with complementary glass transition temperatures. The first resin (lower Tg) provides heat sealability, while the second resin (higher Tg) provides block resistance and water resistance. This composite approach overcomes the limitations of single-material coatings like PLA.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters of the copolymer resins including glass transition temperature (Tg), molecular weight, and composition ratios to achieve the desired balance between heat sealability, water resistance, and biodegradability. The controlled parameter ranges ensure both functional performance and environmental compatibility.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If excessive heat sealability is achieved to ensure proper sealing, then sealing quality is improved, but the paper cup sticks to the mold causing production failures

Engineering Contradiction:
Improvesealing qualityVSAvoidmold separation
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies different coating resins with different properties to different locations or layers of the coating system. The first copolymer resin provides heat sealability at the sealing interface, while the second copolymer resin provides block resistance to prevent sticking to the mold. This spatial differentiation of material properties resolves the contradiction between sealing quality and mold separation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The dual-resin composite coating system allows simultaneous optimization of heat sealability and block resistance. The first resin ensures proper sealing between paper layers, while the second resin prevents adhesion to the mold surface, enabling both high sealing quality and easy mold separation.

Inventive Principle:
Principle #40Composite materials

4Device complexity

If a single coating material is used to simplify the coating process, then manufacturing complexity is reduced, but it is impossible to simultaneously achieve heat sealability, block resistance, and water resistance

Engineering Contradiction:
Improvecoating process complexityVSAvoidheat sealability, block resistance, and water resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent uses a composite coating material consisting of two copolymer resins with complementary properties. The first resin (with lower glass transition temperature) provides heat sealability, while the second resin (with higher glass transition temperature) provides block resistance. This composite approach enables simultaneous achievement of multiple functional requirements that cannot be met by a single coating material.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters of the copolymer resins including glass transition temperature, molecular weight, and composition ratios to achieve the desired balance between heat sealability, block resistance, and water resistance. The controlled parameter ranges ensure both functional performance and environmental compatibility.

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 provides eco-friendly paper cups with excellent heat sealability, water resistance, and block resistance, enabling easy molding, recyclability, and biodegradability without separate film removal, while preventing sticking and ensuring high-quality production at lower costs.

Implementation Method 1

a first coating layer formed of a first coating liquid applied onto the basic paper; and a second coating layer formed of a second coating liquid applied onto the first coating layer, wherein the base paper for eco-friendly paper cups has heat sealability and block resistance

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 2

a first coating layer formed of a first coating liquid applied onto the basic paper; and a second coating layer formed of a second coating liquid applied onto the first coating layer, wherein the base paper for eco-friendly paper cups has heat sealability and block resistance

Methodology Applied
Scientific EffectGlass transition:

Data Source

PatentEP3904596B1Environmentally friendly paper cup base paper
Publication Date: 2026.04.01 HANKUK PAPER MFG
  • EP3904596B1 patent drawingFigure 1~3
  • EP3904596B1 patent drawingFigure 4~5
  • EP3904596B1 patent drawingFigure 6~7

AI summary

Disclosed is a base paper for eco-friendly paper cups and, more specifically, to a base paper for eco-friendly paper cups, which is eco-friendly by having recyclability and biodegradability while retaining water resistance, oil resistance, heat sealability, and block resistance required as a base paper for paper cups.