Printable Wax-Free Twist Wrapper for Grease Resistance and Twisting Strength
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Solution Overview
Problem
Existing twist wrappers for sweets are either waxed, making them difficult to print and non-recyclable, or wax-free but lacking in mechanical strength and barrier properties, and they are not suitable for high-throughput packaging.
Innovation Solution
A process to create a wax-free twist wrapper using a paper substrate made from a mixture of hardwood and softwood pulps, coated with a print receiving layer and a barrier layer of styrene or polyvinyl alcohol polymers, achieving a moisture content of 5-15% and a density of 1 g/cm³, allowing for easy printing and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wax is used to impregnate the wrapper, then barrier properties and mechanical strength are improved, but printability deteriorates and recyclability is lost
Solution Approach 1:
The patent removes the wax impregnation step from the wrapper manufacturing process. Instead of waxing the wrapper after printing, the invention uses a wax-free paper composition that inherently provides barrier properties through its cellular structure and coating, eliminating the need for separate waxing operations and enabling post-printing or simultaneous printing.
Solution Approach 2:
The patent employs a composite paper composition combining hardwood and softwood pulps with specific coatings (such as gelatin or albumin) to achieve both mechanical strength and barrier properties without wax. The hardwood pulp provides strength while the softwood pulp and coating layers provide grease resistance, creating a multi-functional material that replaces waxed paper.
2Object-affected harmful factors
If wax is used to impregnate the wrapper, then barrier properties are improved, but recyclability deteriorates
Solution Approach 1:
The invention extracts and eliminates the wax component from the wrapper system, replacing it with a biodegradable paper-based barrier layer. This removes the harmful element (wax) that prevents recycling while maintaining the protective barrier function through natural paper structure and plant-based coatings.
Solution Approach 2:
The patent changes the chemical composition parameters of the wrapper by substituting wax (hydrophobic, non-biodegradable) with water-soluble or biodegradable coatings and controlling the cellulose fiber composition. This parameter change maintains barrier properties through controlled porosity and coating thickness while enabling recycling through standard pulping processes.
3Ease of manufacture
If printing is performed before waxing, then printability is maintained, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the printing and barrier layer application into a single simultaneous process. The wrapper is printed and the barrier coating is applied in one operational sequence, eliminating the need for separate pre-printing and post-waxing steps. This integration reduces manufacturing complexity while maintaining print quality and barrier performance.
Solution Approach 2:
The invention applies the barrier coating to the wrapper surface before printing, allowing the printing process to occur on a prepared surface that will maintain its barrier properties. This preliminary coating action ensures that the printing surface is suitable for ink adhesion while preserving the eventual barrier function, eliminating the need for post-printing waxing.
4Object-affected harmful factors
If conventional wrapper materials are used, then barrier properties are achieved, but mechanical strength during twisting deteriorates
Solution Approach 1:
The patent uses a composite paper structure combining hardwood pulp (providing tensile strength and flexibility) with softwood pulp (providing compressive strength and twist resistance). The specific ratio and bonding of these pulps create a material that maintains barrier properties while withstanding the mechanical stresses of twisting and packaging operations.
Solution Approach 2:
The invention applies different properties to different layers of the wrapper composition. The hardwood pulp layer provides flexibility and tear resistance, while the softwood pulp and coating layers provide grease barrier properties. This local differentiation of material properties allows the wrapper to simultaneously achieve both strength during twisting and effective barrier protection.
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 wrapper exhibits excellent mechanical properties, grease resistance, and recyclability, enabling high-speed packaging of sweets without the need for pre-printing, and is comparable to conventional waxed wrappers in strength and durability.
Implementation Method 1
a barrier layer to form a printable twist wrapper precursor... wherein said barrier layer comprises, or substantially consists of, a barrier polymer chosen among polymers or copolymers of styrene, or polymers or copolymers of polyvinyl alcohol
Implementation Method 2
forming a paper substrate from a paper furnish comprising paper pulp... having a moisture content of from 5% to 15%
Data Source
AI summary
A wax-free printable twist wrapper having a grease resistance value of 4, or of from 4 to 12, when measured according to TAPPI Test method T559, and comprising, or consisting of, a paper substrate comprising a mixture of at least one hardwood pulp and at least one softwood pulp, said mixture having a degree of Schopper-Riegler between 35 and 50, preferably 35 and 40, and comprising at least 40 % by weight of at least one hardwood pulp, a print receiving layer on one side of the paper substrate, said print receiving layer comprising at least one binder and at least one clay pigment, and a barrier layer on the other side of the paper substrate, wherein said printable twist wrapper has a moisture content of from 5% to 15% and has a density of 1 g/cm3 or more.