Coinjected Blow Molded Wall Structure for Gloss and Delamination Resistance
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Solution Overview
Problem
Existing blow molded articles with effect pigments suffer from poor gloss, high haze, and are prone to delamination due to random orientation of platelet-like particles, making them unsuitable for mass production and premium appearance applications.
Innovation Solution
A multilayer blow molded article with a transparent outer layer and a layer containing effect pigments sandwiched between, produced via parallel flow co-injection, ensuring the pigments are oriented parallel to the surface for improved gloss and reduced haze, and the layers are interpenetrated for enhanced adhesion and delamination resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If effect pigments are introduced in large scale blow molding operations, then visual appeal and premium appearance are improved, but the pigment particles remain dispersed in random orientation reducing the effect and creating poor gloss and high haze
Solution Approach 1:
The invention divides the wall structure into three distinct layers: an outer layer containing effect pigments, an intermediate layer, and an inner layer. This segmentation allows the effect pigment layer to be optimized for visual appearance while the other layers provide structural support and control the dispersion orientation of pigment particles, resolving the contradiction between achieving premium appearance and maintaining manufacturing precision.
Solution Approach 2:
The invention applies different properties to different parts of the wall structure. The outer layer is specifically designed with effect pigments for visual appeal, while the intermediate and inner layers have compositions optimized for structural integrity and pigment orientation control. This local differentiation allows simultaneous achievement of high gloss and precise pigment orientation.
2Illumination intensity
If effect pigments are applied using standard coating application techniques such as painting or printing, then visual effects are achieved, but complexity, costs increase and additional problems such as need for lacquering arise
Solution Approach 1:
The invention merges the effect pigment application with the blow molding process itself by incorporating effect pigments directly into the outer layer material that is extruded during molding. This eliminates the need for separate coating, printing, or lacquering steps, thereby achieving visual effects while reducing process complexity and costs.
Solution Approach 2:
The outer layer serves multiple functions simultaneously: it provides the visual effect through effect pigments, acts as a surface layer for the article, and controls the orientation of pigment particles. This multi-functionality eliminates the need for separate coating processes, reducing overall process complexity.
3Illumination intensity
If a multilayer structure with inner layer comprising pearlescent agent and outer layer being transparent is produced using two-steps methods, then gloss is improved, but mechanical resistance decreases so that layers may separate during use
Solution Approach 1:
The invention uses a composite three-layer structure where each layer has specific compositional characteristics. The outer layer contains effect pigments for visual effect, the intermediate layer provides bonding and mechanical strength, and the inner layer provides structural support. This composite structure maintains high gloss while preventing layer separation through optimized interlayer bonding.
Solution Approach 2:
The intermediate layer acts as a mediator between the outer effect pigment layer and the inner structural layer. It provides optimal bonding characteristics that ensure strong adhesion between layers, preventing delamination while allowing the outer layer to maintain its visual effects. The intermediate layer composition is specifically designed to bridge the mechanical properties of the other two layers.
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 achieves high gloss, low haze, and improved resistance to delamination, enabling cost-effective mass production of visually appealing containers with a premium appearance.
Implementation Method 1
The optical effects of these pigment (which are described in the art as luster, pearlescence, iridescence, metallic effect) arises from reflection of incident light from the smooth surface of the pigment platelets... the platelet like particles spontaneously orient in a direction parallel to the surface to which they are applied
Implementation Method 2
The optical effects of these pigment (which are described in the art as luster, pearlescence, iridescence, metallic effect) arises from reflection of incident light from the smooth surface of the pigment platelets
Data Source
Figure 1A~1C
Figure 2
AI summary
A blow molded article obtained by blow molding of a preform made via parallel flow coinjection, having a wall formed by 3 layers in at least a region wherein the outside layer is transparent and the inner layer comprises an effect pigment visible through the transparent layer. Articles according to the invention have an improved gloss, low haze and higher resistance to delamination than previous articles. The invention relates also to preforms for making articles as described and to methods for making preforms and articles.