Blister Pack Absorbing Layer Resolving Molding Defects

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Solution Overview

Problem

Blister packages face molding defects, such as cracking or pinholes, when forming deep pockets, which affects the moldability and stability of pharmaceutical preparations within.

Innovation Solution

The absorbing layer is composed of an outer skin layer, an intermediate layer with an inorganic absorbent and binder resin, and an inner skin layer made from metallocene-based and non-metallocene-based random polypropylene resins, with a specific surface roughness and composition to reduce friction and tensile stress during pocket formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a dome-shaped pocket is formed in a laminate consisting of a barrier layer and an absorbing layer to package large pharmaceutical preparations, then the capacity to hold large preparations is improved, but molding defects such as rupturing of the roof or formation of cracks in the skirt or shoulder occur

Engineering Contradiction:
Improvepocket capacityVSAvoidmolding quality
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The invention uses a composite laminate structure consisting of a barrier layer and an absorbing layer with specific material properties. The absorbing layer contains a resin composition with controlled molecular weight and composition that provides both the necessary deformability for deep pocket molding and the structural integrity to prevent cracking and rupturing during the molding process.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention controls the molecular weight and composition parameters of the resin in the absorbing layer. By specifying that the resin has a weight-average molecular weight of 100,000 or more and consists of specific polypropylene components, the material achieves optimal balance between deformability for deep molding and strength to prevent molding defects.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a reinforcing layer using a specific polymer is inserted between the aluminum layer and the absorbing layer to improve moldability, then moldability is improved considerably, but depending on the type of molding machine or molding depth, the shoulder of the pocket ends up cracking or pinholes form

Engineering Contradiction:
ImprovemoldabilityVSAvoidpocket integrity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention removes the reinforcing layer that was previously inserted between the aluminum layer and the absorbing layer. Instead, it achieves the desired moldability and pocket integrity by optimizing the resin composition and molecular weight characteristics of the absorbing layer itself, thereby eliminating the source of cracking and pinhole defects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the material parameters of the absorbing layer by specifying a weight-average molecular weight of 100,000 or more and specific resin composition ratios. This enables the absorbing layer to provide sufficient strength and deformability without requiring an additional reinforcing layer, thus preventing shoulder cracking and pinhole formation.

Inventive Principle:
Principle #35Parameter changes

3Length of stationary object

If the absorbing layer uses conventional resin composition to achieve deep pocket formation, then the depth of the pocket is improved, but friction and tensile stress during molding increase causing defects

Engineering Contradiction:
Improvepocket depthVSAvoidresistance to fracture
Core Design Contradiction:
Length of stationary objectVSStrength

Solution Approach 1:

The invention optimizes the resin parameters by specifying a weight-average molecular weight of 100,000 or more and specific compositional ratios of polypropylene components. This enables the material to achieve deep pocket formation while maintaining sufficient strength to resist fracture, reducing both friction and tensile stress during the molding process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite resin composition within the absorbing layer that combines specific polypropylene components with controlled molecular weight and composition ratios. This composite material structure provides the necessary balance between deformability for deep molding and strength to prevent cracking under tensile stress.

Inventive Principle:
Principle #40Composite materials

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

This configuration minimizes molding defects, allowing for the production of blister packages with deep pockets that maintain stability and prevent deterioration of pharmaceutical contents over time.

Implementation Method 1

a desiccant such as silica gel has conventionally been enclosed within the outer pouch that encloses the blister package... there is also the need to be able to absorb oxygen and odors present within the blister package

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

if a transparent packaging container is used, there is the risk of degradation of the pharmacologically active ingredient... ultraviolet light can be blocked

Methodology Applied
Scientific EffectAbsorption of ultraviolet light: Absorption (EM radiation)

Implementation Method 3

an inner skin layer made from metallocene-based and non-metallocene-based random polypropylene resins, with a specific surface roughness and composition to reduce friction and tensile stress during pocket formation

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP3159279B1Absorbent layer for blister packs, laminate comprising same, and blister pack using said laminate
Publication Date: 2020.03.04 KYODO PRINTING CO LTD
  • EP3159279B1 patent drawingFigure 1~2

AI summary

The purpose of the present invention is to provide an absorbent layer for blister packs, which imparts sufficient formability and is free from forming failure even if a pocket part is formed to a certain depth. An absorbent layer for blister packs, which sequentially comprises, in the following order, an outer skin layer, an intermediate layer containing an inorganic absorbent and a binder resin, and an inner skin layer containing 5-80% by mass of a metallocene polypropylene and 95-20% by mass of a non-metallocene polypropylene.