Variable-Thickness Round PET Cosmetic Bottles for Easier Squeezing

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Solution Overview

Problem

Existing plastic bottles for cosmetic compositions, particularly those made from recycled polyethylene terephthalate (PET), are difficult to squeeze, especially when nearly empty, leading to consumer inconvenience and inefficiency.

Innovation Solution

A round plastic bottle design featuring a bottle wall with at least one thicker second wall segment and one thinner first wall segment, produced via stretch blow molding, allowing for easier squeezing and reduced material use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the bottle wall is made thick to ensure durability and structural integrity, then the bottle becomes difficult to squeeze, especially when nearly empty

Engineering Contradiction:
Improvebottle wall strengthVSAvoidease of squeezing
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The bottle wall is designed with varying thickness: thicker at the bottom (BB) and neck (BN) regions for structural integrity, and thinner at the main body (BW) region for ease of squeezing. This local differentiation allows the bottle to maintain strength where needed while being easily squeezable where content dispensing occurs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bottle wall is divided into distinct segments with different thickness characteristics: a thick bottom segment, a thin main body segment, and a thick neck segment. This segmentation enables each part to perform its specific function optimally - the thick bottom provides stability, the thin body allows squeezing, and the thick neck maintains cap attachment strength.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If recycled PET is used to manufacture the bottle, then environmental sustainability is improved and production costs are reduced, but the bottle becomes very stiff and difficult to squeeze

Engineering Contradiction:
Improveproduction cost and sustainabilityVSAvoidease of squeezing
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

By applying local quality variation through differential wall thickness, the invention enables recycled PET bottles to be easily squeezed despite the inherent stiffness of the material. The thinner main body wall reduces the overall rigidity while the thicker bottom and neck maintain necessary structural functions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the physical parameter of wall thickness distribution to transform the squeezing characteristics of recycled PET bottles. By reducing wall thickness in the main body region, the bottle becomes sufficiently compliant for easy squeezing while maintaining material strength where structurally necessary.

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If a round shape is used for the bottle, then plastic material usage is minimized, but the bottle may lack structural rigidity

Engineering Contradiction:
Improveplastic material usageVSAvoidstructural rigidity
Core Design Contradiction:
Loss of substanceVSStrength

Solution Approach 1:

The round bottle shape is maintained for material efficiency, while local quality variations in wall thickness provide the necessary structural rigidity. The thicker bottom and neck regions compensate for the inherent lower rigidity of round shapes, enabling the bottle to maintain both minimal material usage and adequate structural strength.

Inventive Principle:
Principle #3Local quality

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 innovative bottle design enables comfortable squeezing throughout the contents' depletion and supports environmental sustainability through the use of recycled PET, while minimizing plastic material usage.

Implementation Method 1

the wall of the second wall segment (B) is thicker than the wall of the first wall segment (A)... the consumer has a more comfortable squeeze experience when squeezing out the cosmetic composition

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

produced via stretch blow molding

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

produced via stretch blow molding

Methodology Applied
Scientific EffectThermal softening: Heating

Data Source

PatentEP4596203A1A round plastic bottle for cosmetic compositions
Publication Date: 2025.08.06 WELLA GERMANY GMBH
  • EP4596203A1 patent drawingFigure 1~2
  • EP4596203A1 patent drawingFigure 3~4
  • EP4596203A1 patent drawing

AI summary

The present invention relates to a round plastic bottle for cosmetic compositions comprising a bottle neck (BN), a bottle bottom (BB) and a bottle wall (BW), wherein the bottle wall (BW) comprises at least one first wall segment (A) and at least one second wall segment (B), wherein the wall of the second wall segment (B) is thicker than the wall of the first wall segment (A). The present invention further relates to a method for the preparation of the inventive round plastic bottle and to the use of the inventive round plastic bottle for carrying or storing cosmetic compositions, especially for carrying or storing shampoo or hair conditioner. In addition, the present invention relates to a container comprising an inventive round plastic bottle and a cap (C).