MDO Polyethylene-Polypropylene Blend Labelstocks
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Solution Overview
Problem
Existing labelstocks face challenges with dispensability and printability due to excessive release values between the label facestock and liner, leading to issues like 'standing-off' and wrinkling, especially at high line speeds, and down-gauging results in low stiffness, affecting dispensing and conformability.
Innovation Solution
A die-cuttable and printable adhesive labelstock comprising a machine direction oriented monolayer or multilayer film facestock with a mixture of propylene polymer or copolymer and polyethylene, where the film is stretched in the machine direction at temperatures between the melting points of polyethylene and propylene, enhancing stiffness, conformability, and printability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If down-gauging of label films is performed to improve cost performance ratio, then cost performance is improved, but stiffness in machine direction becomes too low to guarantee good dispensing
Solution Approach 1:
The patent changes the material composition parameters by using a blend of polypropylene and polyethylene polymers with specific weight ratios (20-80% polyethylene, 80-20% polypropylene), and controls the stretching temperature parameter between the melting points of the two polymers to achieve optimal stiffness and conformability balance
Solution Approach 2:
The patent creates a composite material system by blending polypropylene and polyethylene polymers in specific proportions, combining the cost-effectiveness of polyethylene with the stiffness properties of polypropylene to achieve both economic and functional requirements
2Strength
If polypropylene materials with higher modulus of elasticity are used to overcome low stiffness, then stiffness is improved, but conformability deteriorates and printability with UV based inks becomes difficult
Solution Approach 1:
The patent modifies the material parameters by blending polyethylene (20-80% by weight) with polypropylene (80-20% by weight), creating a composite that reduces the modulus of elasticity compared to pure polypropylene, thereby improving conformability and UV ink printability while maintaining sufficient stiffness
Solution Approach 2:
The patent develops a composite polymer material combining polyethylene and polypropylene in specific ratios, where the polyethylene component softens the material to improve conformability and printability, while the polypropylene component maintains the necessary stiffness for dispensing
3Productivity
If high line speeds are used for label application, then productivity is improved, but dispensing reliability deteriorates due to excessive release values and label wrinkling
Solution Approach 1:
The patent changes the facestock material parameters by using a polyethylene-polypropylene blend with controlled composition ratios and specific stretching temperature processing, which optimizes the balance between release characteristics and label stiffness to enable reliable dispensing at high line speeds
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 labels with improved stiffness, conformability, and printability, ensuring reliable dispensing and high-speed application while maintaining cost-effectiveness by using a combination of propylene and polyethylene polymers in the facestock.
Implementation Method 1
stretching the extruded film in the machine direction at a stretching temperature of from about the melting temperature of the polyethylene up to the melting temperature of the propylene polymer or copolymer
Implementation Method 2
stretching the extruded film in the machine direction at a stretching temperature of from about the melting temperature of the polyethylene up to the melting temperature of the propylene polymer or copolymer
Data Source
AI summary
Die-cuttable and printable adhesive containing labelstocks for use in preparing die cut adhesive labels, and methods of preparing the labelstocks and die cut labels are described. The labelstocks comprise extruded machine direction oriented monolayer or multilayer films and an adhesive layer. The monolayer films comprise a mixture of about 25% to 80% by weight of a propylene polymer or copolymer, and from about 20% to about 75% by weight of a polyethylene. The films are stretch oriented in the machine direction at a temperature at about or above the melting temperature of the polyethylenes.