In-Mold Label Antistatic Layer for Low-Humidity Printing

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Solution Overview

Problem

In-mold label production faces issues with static charges in low-humidity environments, leading to inefficiencies in printing and labeling processes, and existing antistatic solutions have poor durability and interfere with the fusibility of resin layers, causing defects and blistering.

Innovation Solution

An in-mold label comprising an olefinic resin substrate layer with a heat-sealable resin layer having a specific antistatic layer, where the wetting indices and initial frictional charge voltage are optimized to prevent static issues, ensuring good adhesion and printability, and the antistatic agent is applied to the heat-sealable resin layer to enhance durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a low-molecular antistatic agent is kneaded in the heat-sealable ethylenic resin layer, then the antistatic performance is improved, but the agent migrates or concentrates in the surface of the heat-sealable resin layer, interfering with fusibility and causing blistering

Engineering Contradiction:

Improveantistatic performanceVSAvoidfusibility and adhesion quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces a polymer antistatic agent as an intermediary substance that provides antistatic functionality without migrating to the surface. This polymer acts as a mediator between the need for antistatic performance and the requirement for proper fusibility, solving the contradiction by providing a stable, non-migrating antistatic mechanism that does not interfere with the heat-sealable resin's bonding properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the molecular parameter of the antistatic agent from low-molecular to polymer molecular weight. This parameter change fundamentally alters the behavior of the antistatic agent, preventing migration and concentration at the surface while maintaining antistatic effectiveness, thus resolving the contradiction between antistatic performance and fusibility.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a low-molecular antistatic agent is applied onto the surface of the heat-sealable ethylenic resin layer, then the antistatic performance is improved, but the durability is poor

Engineering Contradiction:

Improveantistatic performanceVSAvoiddurability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the molecular weight parameter of the antistatic agent from low-molecular to polymer molecular weight. This fundamental parameter change transforms the antistatic agent from a surface-applied substance with poor durability into an integrated polymer component with long-lasting performance, resolving the contradiction between antistatic effectiveness and durability.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If sheets are processed into in-mold labels with sheet offset printing, then the printing sharpness is improved, but static charges are generated causing printing troubles and stacking inefficiency

Engineering Contradiction:

Improveprinting sharpnessVSAvoidprinting speed and stacking efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies a polymer antistatic agent as an intermediary coating on the label surface. This intermediary layer does not interfere with the sharp printing quality achieved by offset printing but effectively dissipates static charges, preventing printing troubles and enabling efficient stacking, thus resolving the contradiction between printing precision and productivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 allows for efficient printing, cutting, and blanking of labels in low-humidity environments with improved adhesion strength to containers, reducing defects and blistering, and maintaining effective antistatic performance.

Implementation Method 1

the absolute value of the initial frictional charge voltage at 23° C. and a relative humidity of 30% of the substrate layer (A) relative to a sheet offset printing blanket is from 0 kV to 15 kV

Methodology Applied

Scientific EffectElectrostatic charge dissipation: Electrostatics

Implementation Method 2

a heat-sealable resin layer (B) having an antistatic layer on its surface

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS8097338B2In-mold label, and labeled resin-labeled article

Publication Date: 2012.01.17 YUPO CORP

AI summary

An in-mold label comprising an olefinic resin substrate layer (A) having a wetting index (α) of from 34 to 74 mN/m and a heat-sealable resin layer (B) with an antistatic layer having a wetting index (β) of from 30 to 54 mN/m, wherein the absolute value of the initial frictional charge voltage of the substrate layer (A) relative to a sheet offset printing blanket is from 0 kV to 15 kV. This label has good workability in printing, cutting and blanking even in a low-humidity environment.