Direct Blow-Molded Container Barrier Properties
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for manufacturing plastic containers with improved barrier properties are costly and environmentally burdensome, and often result in deformation due to uneven polyamide distribution and shrinkage rates during the molding process.
Innovation Solution
A direct-blow molding method using a cylindrical die with a specific mandrel and support structure to disperse and layer metaxylylene group-containing polyamide within a polyolefin matrix, maintaining the polyamide's dispersion and layering to prevent deformation and enhance barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer structure with EVOH interlayer is used to improve barrier properties, then gas barrier property is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent uses a composite material system consisting of polyolefin (A), acid-modified polyolefin (B) as adhesive, and metaxylylene group-containing polyamide (C) dispersed at 5-30 mass% to achieve gas barrier properties comparable to multilayer EVOH structures. This composite approach allows single-layer manufacturing while maintaining barrier performance, thereby reducing manufacturing complexity and cost.
2Reliability
If polyamide is blended with polyolefin to improve barrier properties, then gas barrier property is improved, but uneven distribution and shrinkage cause deformation
Solution Approach 1:
The patent specifies that the metaxylylene group-containing polyamide (C) should be dispersed and localized within the polyolefin (A) matrix with controlled concentration (5-30 mass%). This localized dispersion approach ensures uniform distribution that prevents shrinkage-related deformation while maintaining gas barrier properties. The acid-modified polyolefin (B) further enhances local adhesion between phases.
Solution Approach 2:
The patent controls the melting temperature parameter of the metaxylylene group-containing polyamide (C) to be within a specific range (200-260°C) to ensure proper dispersion and layering during the molding process. This parameter control prevents uneven distribution and shrinkage, thereby maintaining manufacturing precision while achieving improved barrier properties.
3Ease of manufacture
If conventional polyolefin containers are used to reduce cost, then manufacturing cost is reduced, but barrier properties deteriorate
Solution Approach 1:
The patent creates a composite material system using polyolefin (A) as base, acid-modified polyolefin (B) as adhesive (5-30 mass%), and metaxylylene group-containing polyamide (C) as barrier agent (5-30 mass%). This composite formulation achieves gas barrier properties superior to conventional polyolefin containers while maintaining compatibility with existing single-layer manufacturing facilities, thus balancing cost and performance.
4Reliability
If metaxylylene group-containing polyamide is dispersed and layered in polyolefin to improve barrier properties, then gas barrier property is improved, but manufacturing precision deteriorates due to shrinkage
Solution Approach 1:
The patent specifies that the metaxylylene group-containing polyamide (C) should have a melting temperature within 200-260°C and be present at 5-30 mass% in the polyolefin (A). These parameter controls ensure uniform dispersion and layering during molding, preventing shrinkage-induced deformation while maintaining gas barrier properties. The acid-modified polyolefin (B) further stabilizes the system.
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 method produces containers with excellent barrier properties against gases and chemicals, including oxygen, without deformation, using conventional manufacturing facilities with minimal additional investment, and maintains the polyamide's distribution to prevent shrinkage issues.
Implementation Method 1
the metaxylylene group-containing polyamide (C) being dispersed and layered in the polyolefin (A)
Implementation Method 2
melted resin extruded from an extruder flows through the flow hole
Implementation Method 3
the flow path clearance formed between the hollow of the die body and the mandrel defining a resin flow path
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
The present invention provides a method of manufacturing a practical direct-blow molded container having excellent barrier property against fuels, chemicals, various gases including oxygen. The method of manufacturing a practical direct-blow molded container containing the metaxylylene group-containing polyamide (C) being dispersed and layered in the polyolefin (A) includes using a die provided with a die body having a flow hole in which the melted resin extruded from an extruder flows and a cylindrical hollow having an opening in the lower side and the flow hole in the upper side, the opening and the flow hole opening downward and upward, respectively, a mandrel having a tip in the upper side, the tip pointing to the opening of the tip of the flow hole, a flow path clearance formed between the hollow of the die body and the mandrel, the flow path clearance defining a resin flow path, and a support part formed in the flow path clearance, the support part holding the mandrel in the hollow of the die body.