Resin Container Bottom Pattern Transfer via Multilayer Preform
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Solution Overview
Problem
Existing methods for producing resin containers with thickened bottom portions for cosmetics struggle to accurately form three-dimensional patterns while maintaining predetermined thickness, leading to deformation and molding defects such as sink marks and whitening.
Innovation Solution
A method involving two injection molding steps to create a multilayer preform with a thick bottom portion, followed by blow molding with residual heat, where at least one surface of the bottom portion is pressed with a mold to transfer a three-dimensional pattern, ensuring accurate pattern formation and reduced deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a preform with a thick bottom portion is blow-molded to emphasize a luxurious feeling and massive feeling, then the aesthetic appearance is improved, but the three-dimensional pattern cannot be accurately formed and deformation occurs
Solution Approach 1:
The patent applies preliminary action by forming the three-dimensional pattern on the preform bottom portion before blow molding. The mold is designed with a recessed portion that pre-forms the pattern, and this patterned preform is then used in the blow molding process. This preliminary pattern formation ensures that the three-dimensional pattern is accurately transferred to the final container while the thick bottom portion maintains its structural integrity and aesthetic appearance.
2Shape
If a preform with a thick bottom portion and high residual heat is blow-molded, then the luxurious feeling is enhanced, but the bottom portion becomes easily deformed and pattern formation is difficult
Solution Approach 1:
The patent uses preliminary action by pre-forming the three-dimensional pattern on the preform bottom portion before blow molding. The mold's recessed portion creates the pattern in advance, and this pre-patterned preform is then blow-molded. This approach ensures that the pattern is already established before the high residual heat causes deformation, allowing the thick bottom portion to maintain its stability while still achieving the desired aesthetic appearance.
3Shape
If a three-dimensional pattern is formed on the inner surface of the bottom portion, then the aesthetic appearance and anti-agitation function are improved, but the preform requires high residual heat which causes deformation
Solution Approach 1:
The patent applies preliminary action by forming the three-dimensional pattern on the preform bottom portion before the blow molding process. The mold is designed with a recessed portion that pre-creates the pattern, and this patterned preform is then used in blow molding. This ensures that the pattern is established when the material is still stable, allowing accurate pattern formation while maintaining control over the thickness of the bottom portion and preventing deformation during the subsequent blow molding step.
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 approach allows for the accurate formation of three-dimensional patterns on the resin container's bottom portion, enhancing aesthetic appeal and preventing molding defects like whitening, while maintaining a predetermined thickness, thus improving the container's quality and design flexibility.
Implementation Method 1
a blow molding step of blow-molding the multilayer preform in a state of having residual heat form injection molding
Data Source
AI summary
A producing method for a resin container includes a first injection molding step of injection-molding an intermediate molded body that has a bottomed cylindrical shape and is made of resin, a second injection molding step of injection-molding a resin material into the intermediate molded body to produce a multilayer preform in which a resin layer is laminated on the intermediate molded body, and a blow molding step of blow-molding the multilayer preform in a state of having residual heat from injection molding to produce a resin container. The multilayer preform is formed such that a bottom portion is thicker than a body portion. In the blow molding step, at least one surface of the bottom portion of the multilayer preform is pressed with a mold, and a three-dimensional pattern corresponding to the mold is transferred to a thick bottom portion of the resin container.