Want to learn more about inner bag vacuum bottles? A guide to help you understand it from all angles

What is an inner bag vacuum bottle? What types of cosmetic packaging is it suitable for?

Basic definition of inner bag vacuum bottle

The inner bag vacuum bottle is a packaging container with a special structure. Its inner liner is a combination of a flexible plastic bag (also called an inner bag) and an outer hard shell. The contents in the bottle are not directly in contact with the air. The vacuum pressure generated by the bottle cap or pump head causes the inner bag to gradually shrink, thereby achieving the output of the contents. This type of structure helps to delay product oxidation, reduce content waste, and improve overall packaging efficiency.

Unlike traditional vacuum bottles, the internal mechanism of the inner bag vacuum bottle is more sophisticated. When the user presses the pump head, instead of letting air enter the bottle to push the contents up, the inner bag in the bottle shrinks while the outer shell is fixed, thereby discharging the internal substances. This non-contact discharge method helps to extend the shelf life of the product and avoid backflow contamination.

 

Structural composition of inner bag vacuum bottle

The inner bag vacuum bottle is mainly composed of the following parts:

*Outer bottle (shell): usually made of hard plastic such as PP, PETG, PET and other materials, which plays a supporting and protective role;

*Inner bag (soft bag): made of multi-layer materials with high barrier properties such as PE and EVOH co-extruded film, with good flexibility and sealing;

*Pump head system: used to form negative pressure to push the contents inside the inner bag to release, often equipped with locks and anti-seepage devices;

*Bottle cap or dust cover: to ensure cleanliness and safety during transportation and storage.

The multi-layer structural design of the inner bag vacuum bottle, especially with the support of high-end manufacturing equipment, can achieve physical isolation of internal and external materials, block air and light, and reduce the possibility of oxidative degradation.

 

Working principle of inner bag vacuum bottle

The inner bag vacuum bottle shrinks the soft bag inside the bottle body by pressing the negative pressure generated by the pump head, so that the contents inside are slowly squeezed out. Unlike traditional bottles, the bottle will not be filled with gas or "rebound" due to the discharge of substances, so there will be no problem of external air entering, reducing the contact between the contents and oxygen from the source.

This working method not only helps to maintain the physical and chemical stability of the product, but also reduces the possibility of bacterial invasion. Especially in cosmetics with high water content, high concentration of active substances, and sensitive to the external environment, this bottle structure is more practical.

 

Overview of the advantages of inner bag vacuum bottles

Inner bag vacuum bottles have the following advantages in cosmetic packaging:

* Blocking air: effectively delaying the oxidation of the contents and keeping the ingredients stable;

* Reducing waste: The inner bag can be almost completely shrunk, and the utilization rate is high;

* Isolating pollution: Avoiding secondary contamination of the contents due to pump reflux;

* Wide range of applications: liquids, lotions, essences, creams, etc. can be adapted;

* Convenient to use: users can press smoothly, the liquid is discharged evenly, and there is no need to shake repeatedly.

Especially suitable for the packaging needs of high-end skin care products, medical repair products or organic natural formula products with high stability requirements.

 

Types of cosmetics suitable for packaging in inner bag vacuum bottles

According to their characteristics, inner bag vacuum bottles are suitable for a variety of cosmetics, mainly including but not limited to the following categories:

1. Essence products

Essences usually contain high concentrations of active ingredients, such as vitamin C, hyaluronic acid, peptides, etc., which are extremely sensitive to oxidation. Inner bag vacuum bottles can effectively block air from entering and delay their decomposition.

2. Highly moisturizing lotions and creams

Cream products have a thick texture, traditional hoses are prone to residue, and ordinary bottles are prone to deterioration. Using inner bag vacuum bottles can improve the efficiency of liquid discharge while keeping the cream fresh.

3. Sensitive skin care products

Such as repair sprays, soothing lotions, etc., the ingredients are closer to the natural state, with low tolerance to pollution and chemical changes, and the inner bag structure can provide a more secure closed environment.

4. Sunscreen products

Some sunscreens are prone to failure when exposed to air. Using inner bag vacuum bottles with high barrier materials can reduce the impact of light and air.

5. Additive-free formula cosmetics

Organic or all-natural formulas often do not contain preservatives and are more sensitive to storage conditions. Vacuum bottles with inner bags can help slow down the rate of deterioration.

 

Comparative analysis with other packaging forms

In order to more intuitively understand the applicability of the inner bag vacuum bottle, we can make a brief comparison with common packaging forms:

 

This comparison shows that the inner bag vacuum bottle has a stronger overall performance in terms of quality preservation, safety and completeness of use, and is suitable for mid-to-high-end market positioning.

 

Future development trends and design directions

As consumers pay more and more attention to the ingredients of skin care products, brands are also beginning to pay more attention to the role of packaging in product preservation and safety. In the future, the inner bag vacuum bottle may continue to develop in the following aspects:

*Material upgrade: use more environmentally friendly recyclable or degradable materials;

*Lightweight structure: reduce the burden on the bottle and improve portability;

*Intelligent packaging: combine the use of metering, visible remaining quantity, bottle opening reminder and other functions;

*Richer design language: such as gradient color bottle, metal texture, matte surface treatment, etc., to meet diverse aesthetics.

 

Why is the "inner bag vacuum bottle" becoming more and more important?

The inner bag vacuum bottle is not only a packaging form, but also reflects the contemporary cosmetics industry's positive response to the three major trends of "safety, environmental protection, and completeness of use". As consumer demand becomes more and more refined, the focus on the packaging system is no longer limited to the visual design level, but more on the actual impact of packaging on product preservation and use experience. For brands, purchasers and even end consumers, understanding and correctly selecting the inner bag vacuum bottle will help improve the overall competitiveness of the product and user satisfaction.

 

What are the common benefits of using an inner bag vacuum bottle?

Delay product oxidation and improve storage stability

The biggest structural feature of the inner bag vacuum bottle is its double-layer packaging design: the inside is a flexible inner bag and the outside is a solid bottle shell. After each press, the negative pressure generated by the pump head will gradually shrink the inner bag, thereby discharging the contents and preventing outside air from entering the bottle. This sealed state effectively isolates oxygen and reduces the oxidation reaction of active ingredients, which is conducive to maintaining the original chemical properties and biological activity of the product. It is especially suitable for formulas containing high-concentration vitamins, plant essences, fruit acids and other ingredients.

 

Improve utilization rate and reduce content waste

Compared with traditional hoses or pump bottles, the inner bag vacuum bottle has a higher content release efficiency. Its internal flexible inner bag will almost completely shrink during continuous pressing, so that the contents in the bottle are discharged to the maximum extent, and the residual amount is significantly reduced. Users can feel a relatively stable liquid output until it is exhausted during use, thereby improving the overall packaging utilization rate, saving costs, and being more in line with sustainable consumption trends.

 

Reduce the use of preservatives and make the formula simpler

When cosmetics are in frequent contact with air, they are easily contaminated by microorganisms such as bacteria and fungi, so preservatives are usually added to maintain their stability. The inner bag vacuum bottle has strong sealing and oxygen barrier properties, which effectively reduces the possibility of microbial entry during storage, thereby reducing the product's dependence on preservatives, supporting the streamlined formula, and meeting the pursuit of low-irritation, no-additive skin care concepts.

 

Reduce pump head reflux and reduce the risk of cross-contamination

During repeated pressing and use of the conventional pump head structure, there is a pump body back-absorption phenomenon, that is, some air or pollutants may be brought back into the bottle, increasing the risk of contamination of the contents. The pump body design of the inner bag vacuum bottle is usually equipped with a one-way valve to prevent the reflux of external air, and with the shrinkable inner bag structure, the contents are kept in a closed environment from beginning to end, greatly reducing the probability of cross-contamination.

 

Improve convenience and suitable for a variety of usage scenarios

The inner bag vacuum bottle has good portability and liquid discharge control. Due to the high control accuracy of the pump head and uniform liquid discharge, users can use it in moderation according to the needs of different scenarios. The outer shell material is relatively strong, suitable for mobile scenes such as travel, commuting, and gyms. It is not easy to leak or deform. While meeting daily skin care habits, it also enhances the adaptability of the product in mobile consumption scenes.

 

Supports multiple textures and strong packaging compatibility

Inner bag vacuum bottles are not only suitable for liquid products with strong fluidity, but also for creams and gels with thicker textures. This type of bottle can be equipped with pump heads and outlet apertures of different specifications according to the consistency of the contents, so as to achieve a smooth liquid discharge experience. In contrast, hose packaging often has problems such as difficulty in extrusion and rebound deformation in the later stage of use, while the inner bag structure can smoothly release the contents under uniform pressure and maintain stability.

 

Conducive to brand building and improving product grade

Inner bag vacuum bottles mostly use transparent or frosted bottle designs, with surface processes such as electroplating, spraying, and silk screen printing, and have a strong appearance shaping space. Its high-end packaging image is easy to attract consumers' attention and help brands upgrade their image in the mid-to-high-end skin care market. In addition, the transparent shell can be matched with the window design, so that consumers can intuitively see the remaining usage, and enhance the trust and interaction between users and products.

 

Adapt to the trend of environmental protection, high material recyclability

Modern consumers are paying more and more attention to the environmental protection of product packaging. The material selection of inner bag vacuum bottles has become diversified, and the commonly used PP, PE, PET, EVOH, etc. have good recycling value. At the same time, with the advancement of manufacturing technology, some brands are also exploring the use of inner bag bottles made of degradable or bio-based materials to further meet the trend of green consumption. Compared with traditional packaging such as multi-layer composite hoses that are difficult to recycle, inner bag vacuum bottles have more potential to play a role in the direction of sustainable packaging.

 

Reduce product volatility and control odor changes

Some skin care products or fragrance products may evaporate, fade or deteriorate when exposed to air. The inner bag vacuum bottle has a tight structure, which can effectively slow down the volatilization rate of moisture and aromatic molecules, thereby maintaining the original fragrance and formula integrity of the product during the use cycle. This feature is particularly important for products such as aromatherapy essences and sunscreen sprays that have high requirements for odor and stability.

 

Facilitates accurate measurement and user experience management

The pump head system of the inner bag vacuum bottle usually has a good quantitative liquid discharge function, which helps users control the amount of each use, thereby achieving scientific skin care management. At the same time, because the discharge process of the contents is smooth and smooth, it is not easy to have a sudden large amount of spraying or dripping, so the user experience is more consistent, reducing the uncertainty of use under different temperatures, pressures or storage environments.

 

Support high-end customization and functional integration

With the increasing demand for personalized product packaging, the inner bag vacuum bottle has gradually become a choice that takes both functionality and design into consideration. Some customized versions already have functions such as dual-chamber structure, UV barrier materials, and anti-counterfeiting label integration, which can be customized exclusively with product differentiation positioning to help brands improve product competitiveness from the packaging level.

 

Comprehensive benefits of the inner bag vacuum bottle

As a packaging form with advanced structure, the benefits of the inner bag vacuum bottle are not only reflected in the basic functions such as sealing and freshness, but also in that it integrates packaging design, safe use, ingredient protection and environmental protection concepts. For cosmetics brands that need to ensure the stability of active ingredients, reduce waste, and strengthen brand image, it is not only a packaging option, but also a solution that meets market trends and user needs.

As the market continues to pay more attention to the quality of skin care products, packaging experience and environmental protection concepts, the application scope of vacuum bottles with inner bags in the cosmetics industry in the future is expected to continue to expand and become one of the important supporting tools for customized and high-end products.

 

How to choose a suitable inner bag vacuum bottle according to product characteristics?

Identify the dosage form of the product

Different types of cosmetics or skin care products have great differences in texture, such as liquid, lotion, paste, gel, essential oil, etc. The inner bag vacuum bottle is designed to support a variety of dosage forms, but in order to ensure smooth liquid discharge, the pump head structure and inner bag material still need to be selected according to the actual texture. For example, low-viscosity fluid liquids (such as toners and essences) can be equipped with fine mist nozzles or standard pump heads, while high-viscosity creams and essences need to be equipped with pump heads with larger outlet diameters and flexible inner bags to prevent jams or unsmooth squeezing.

 

Consider the activity and storage requirements of the product's ingredients

Whether the ingredients contain substances that are sensitive to light, heat, and air is an important basis for selecting an inner bag vacuum bottle. If the formula contains easily oxidized ingredients such as vitamin C, retinol, peptides, and plant active ingredients, multi-layer inner bag bottles with high barrier properties (such as EVOH inner layer) should be given priority, and a bottle body structure with light-shielding ability should be selected. In addition, it is also necessary to evaluate whether the bottle is suitable for low-temperature/high-temperature storage environments to avoid material aging or deformation.

 

Evaluate the frequency of use and single dosage

The frequency of use of the product (once or more per day) and the amount used each time determine the required capacity and quantitative capacity of the pump head. If the product is a high-frequency, small-dose product (such as eye essence, anti-wrinkle essence), you can choose a small-capacity (15ml30ml) inner bag bottle with precise pump volume control; while large-volume products such as body lotion and facial cleanser are suitable for 50ml150ml capacity, and the pump head has a relatively large liquid output, which can complete the use action faster.

 

Identify whether a visual design is needed

Inner bag vacuum bottles can be divided into two types: visible and opaque. Some users want to know the remaining amount of the product. At this time, a transparent shell or a bottle with a window design can be selected to view the changes in the contents; but if the contents are easily degraded by light, a frosted or opaque material shell is required, such as a full white or metallic texture design. This design not only prevents light aging, but also better fits the packaging image of high-end positioning.

 

Determine whether the product needs to be equipped with a multi-head or compound pump

Some special-purpose products, such as combined skin care solutions (A+B double tubes, morning and night use partitions), two-step application procedures (priming + repair), may require different formulas to be packaged separately. Therefore, you can choose a double-chamber or multi-chamber structure inner bag vacuum bottle, so that users can achieve multi-functional partitioning operations on the same bottle body, avoid cross-reaction of formulas, and improve the efficiency of use.

 

Confirm the compatibility of the pump body and the liquid discharge form

Depending on the specific way the product is used, it is very important to choose different pump body structures. Common liquid discharge forms include: direct spray type (suitable for toner), fine mist spray type (suitable for sunscreen spray), dropper type (suitable for ampoule essence), and pressure pump type (suitable for lotion/cream). The internal structure and required inner bag pressure of each type of pump head are slightly different. When selecting, you should confirm the spray volume, air tightness, resilience and other technical parameters with the packaging material supplier to ensure the final feel.

 

Consider whether the product needs an airless packaging design

Some high-end skin care products or medical skin care products do not want to have residue or waste after use. You can choose an inner bag vacuum bottle with a "zero residue" function. The inner bag of this type of bottle can be completely shrunk after the last press, without repeatedly shaking or squeezing the bottle. At the same time, the material of the inner bag itself has high flexibility and high shrinkage, and will not cause backlogs at the bottom of the bottle, which helps to improve the user experience.

 

Pay attention to environmental protection attributes and material recyclability

Different brands attach different importance to environmental responsibility. If you want to promote the concept of sustainability, you should choose an inner bag vacuum bottle with recyclable or bio-based materials. For example, the use of PP and PE single-material structure is convenient for recycling system sorting; the use of EVOH barrier layer instead of metal foil is also more conducive to environmental protection. In addition, you can also consider whether it supports modular design with replaceable inner bags to extend the service life of the bottle.

 

Consider whether it is necessary to cooperate with the brand to customize the appearance design

The outer shell of the inner bag vacuum bottle supports a variety of shapes, colors and surface processes, such as painting, electroplating, silk screen printing, hot stamping, etc. If the brand has a visual identification system requirement, it needs to be customized in combination with factors such as bottle curve, label area, and LOGO engraving space. On this basis, it should also be considered whether the bottle structure affects filling, labeling, and logistics transportation stability.

 

Comply with product compliance requirements in the international market

If the product is exported overseas, the appropriate inner bag vacuum bottle should be selected in combination with the cosmetic packaging regulations of various countries. For example, the EU has strict regulations on material contact safety and heavy metal limits; the United States has higher standards for pump head safety and non-resorption performance. Companies should choose materials and packaging solutions certified by FDA, ISO, SGS, etc. to ensure that the product can enter the market smoothly and reduce regulatory risks.

 

Compatibility with production line processes

The inner bag vacuum bottle is slightly different from traditional packaging in filling methods. Some bottles need to fill the contents into the inner bag first, and then the machine completes vacuum extraction and packaging. If the company already has a mature automated filling system, it should give priority to standard calibers and conventional bottle types to avoid increasing modification costs due to special designs. At the same time, it is necessary to confirm whether the bottle supports special requirements such as hot filling, cold filling, or no bubbles during filling.

 

Comprehensive brand positioning and user psychological expectations

Inner bag vacuum bottles are often used in the field of mid-to-high-end skin care products, and their structural design itself has a sense of technology and professionalism. When choosing a packaging solution, brands should combine product pricing, the preferences of the target user group, and the product efficacy positioning. For example, functional skin care products with a strong sense of technology can be matched with metallic appearance and oxygen-blocking materials to highlight the characteristics of "precision and professionalism"; while products that focus on natural and gentle are suitable for matching with plain and environmentally friendly bottle designs to convey a psychological impression of green and safety.

 

Selection needs to take into account multi-dimensional factors

As a packaging solution that combines functionality and aesthetics, the selection process of inner bag vacuum bottles should be based on multiple considerations such as product physical properties, ingredient characteristics, usage methods, brand positioning, and regulatory requirements. By fully communicating with packaging material suppliers, clarifying various indicator parameters, and combining processes such as trial installation and stability testing, companies can more scientifically match suitable bottle types, laying a good foundation for product listing and market competition.

 

Analysis of the role of inner bag vacuum bottles in reducing the use of preservatives

Reasons for the widespread use of preservatives in cosmetics

The use of preservatives has long been considered necessary in cosmetics and personal care products. The main reason is that cosmetics are mostly water-oil mixed systems, especially water-containing products are more susceptible to microbial contamination. Once contaminated, the product may cause skin discomfort or failure. Therefore, in order to extend the shelf life and prevent the growth of microorganisms, manufacturers often add a certain amount of preservatives to the formula. However, in recent years, with the increasing attention of consumers to the concepts of "no additives" and "pure skin care", reducing or even avoiding preservatives has become an important direction of research and development, and the development of packaging technology has also provided support for this goal.

 

Structure and sealing advantages of inner bag vacuum bottle

The inner bag vacuum bottle (Airless Bottle with Inner Bag) is a packaging container with a special structure, in which a flexible inner bag is set inside, and the contents are squeezed out of the outside by a vacuum pump. During use, air will not directly enter the bottle body, but the inner bag will gradually collapse as the contents decrease, thereby realizing a "zero back-absorption" closed system. This sealing structure greatly reduces the frequency of contact between the contents and the air and hands, effectively blocks the entry of bacteria and oxygen, and significantly improves the risk of microbial contamination.

 

Physical prerequisite for reducing preservatives: blocking external pollution sources

The biggest difference between the inner bag vacuum bottle and ordinary open bottle and pressure pump bottle is that the contents are isolated throughout the process. In traditional packaging, each use is accompanied by air backflow, hand contact or water vapor intrusion, which provides a breeding ground for microorganisms and forces the formula to add higher concentrations of preservatives. In the inner bag structure, the bottle body is not in direct contact with the outside air. Even if it is used frequently, its contents are still in a physically closed state, so it is more suitable for the stable storage of low-preservative or even non-preservative formulas.

 

Delaying the oxidation of contents and the failure process of ingredients

Many natural extracts, vitamins, active peptides, plant essences and other ingredients have strong functionality, but they are also very easy to oxidize. For example, vitamin C, vitamin E, and polyphenols will change color and reduce their efficacy in a short time when exposed to air. On the basis of blocking oxygen from entering, the inner bag vacuum bottle reduces the probability of oxidation reaction, so that the formula can remain stable for a long time without relying on high-strength antioxidants and chemical stabilizers, and indirectly reduces the need for the use of preservatives and other additives.

 

Friendly to sensitive skin: Reduce the addition of potential allergens

Some consumers may react to common preservatives such as phenoxyethanol, parabens (Paraben), MIT, CMIT and other ingredients due to skin sensitivity, allergy history or individual differences. Using an inner bag vacuum bottle can help brands design a more "clean" ingredient system and reduce the risk of allergies. Especially in maternal and child skin care products and medical and aesthetic after-care products, the requirements for preservative limits are more stringent, and this packaging form has become a feasible solution to replace the traditional bottle form.

 

Support natural preservative system and minimalist formula strategy

Under the trend of "minimalist skin care", many brands have begun to return to the principle of "less is more", using fewer formula ingredients and emphasizing clear efficacy and transparency. This type of formula is usually supplemented with natural extracts to achieve microbial control, such as mild preservatives such as capryloyl glycine, potassium sorbate, and ethylhexylglycerin. However, these ingredients have limited power against complex microorganisms, and without good packaging support, stability is difficult to guarantee. The inner bag vacuum bottle assists the natural preservative system through external physical protection, making mild formula possible.

 

Reduce the risk of microbial accumulation in long-term storage

After the traditional packaging is opened, each exposure of the product may introduce bacteria, yeast, mold and other microorganisms. Even if the initial test is qualified, microorganisms may still grow over time and form microscopic pollution. The inner bag vacuum bottle effectively delays this process. Even if the use cycle is as long as several months, the state of the inner bag after shrinkage is still relatively vacuum, almost eliminating the conditions for the reproduction of microorganisms in the contents, greatly reducing the probability of later contamination.

 

Provide physical support for the "no additives" label

Some brands have launched conceptual products such as "no preservatives", "no alcohol", and "no irritation additions" to cater to market trends. The compliance of such product labels is subject to regulatory review and ingredient testing restrictions. If ordinary packaging is used, it is easy to add preservatives due to the increased risk of contamination after opening. The use of inner bag vacuum bottles can provide strong support in the packaging process, reduce the compliance pressure of enterprises when operating on the edge of regulations, and at the same time strengthen the "safe" and "environmentally friendly" brand image communication.

 

Storage logic for highly active, small-volume skin care products

Some high-concentration active skin care products, such as anti-aging essences, functional ampoules, and whitening stock solutions, usually have small doses, but have high requirements for the storage environment. Oxidation or contamination will greatly reduce the effect. Using inner bag vacuum bottles to store such products can not only reduce the dependence on preservatives, but also maintain the stability of the ingredients during the use cycle. This is also one of the important reasons why more and more functional brands and professional line products choose vacuum bottle packaging.

 

Help brands cope with regulations and market multiple standards

With the increasingly stringent standards for the use of preservatives in the EU, the United States, Japan and other regions, some preservative ingredients have been banned or restricted in concentration. In this context, the use of inner bag vacuum bottles has become an important means for brands to cope with regulatory restrictions. Packaging instead of preservatives has become a trend. Brands can transfer part of the preservative pressure to the packaging system, reduce the use of high-risk additives in the formula, and respond to different market regulations and standards while ensuring safety.

 

Reduce the conflict of compounding of mutually exclusive ingredients in the formula

There are often compatibility restrictions between high-concentration actives and preservatives. For example, some plant extracts may precipitate or change color when exposed to preservatives, and enzyme ingredients are also prone to degradation or failure when coexisting with antimicrobial agents. By reducing or eliminating preservatives, product compatibility can be improved, providing higher feasibility for all-in-one formulas. In such scenarios, the inner bag vacuum bottle is not only a replacement function, but also a "subtraction-style" formula design tool.

 

Two-way collaboration between physical protection and chemical burden reduction

In the current development context of the cosmetics industry, consumers are increasingly sensitive to ingredients, and brands are increasingly pursuing "formula simplification" and "natural safety". The inner bag vacuum bottle, with its excellent sealing, oxygen isolation, and anti-backflow properties, creates a reliable packaging environment for formulas that reduce or do not use preservatives. This type of packaging not only solves the problem of microbial safety, but also drives multi-dimensional innovations in skin care concepts, formula research and development, and brand marketing.

 

Key points of airtightness and barrier performance testing of inner bag vacuum bottles

The role of air tightness and barrier properties in cosmetic packaging

As the cosmetics industry's requirements for packaging functions increase, air tightness and barrier properties have become key indicators for measuring high-quality inner bag vacuum bottles. Good air tightness can prevent air, moisture or microorganisms from entering the container, preventing oxidation, contamination and deterioration of the contents, while barrier properties are directly related to the active stability of the contents during long-term storage or use. Through systematic testing and evaluation, it can be determined whether the packaging materials and structures can meet the basic requirements of the product for preservation, protection and hygiene.

 

The core definition and difference between air tightness and barrier properties

Air tightness refers to the ability of a container to prevent air penetration or leakage under the influence of external pressure or natural environment. It emphasizes the "sealing" ability and is directly related to whether the contents are exposed to the external air environment.

Barrier properties focus more on the material layer's ability to resist penetration of specific media such as gas, water vapor, microorganisms, and light, and are usually closely related to the multi-layer material structure and the tightness of its molecular arrangement. The two together constitute the technical basis for the inner bag vacuum bottle to protect the stability of the product.

 

Factors affecting the air tightness test by structural characteristics

*Inner bag vacuum bottles are generally composed of three parts: bottle body shell, inner bag (soft container), and vacuum pump head. The following factors are important sources of influence on air tightness test:

*The connection sealing between the inner bag and the bottle cap: Whether the thread, buckle or hot melt method is stable determines the degree of sealing.

*The valve system designed by the pump head: The rebound elasticity and the effective closing state of the one-way valve are particularly critical to the control of the back-inhaled gas.

*The physical elasticity and deformation response ability of the material: Whether the inner bag is broken or deformed under vacuum will affect the continuous sealing effect.

In the air tightness test, it is necessary to simulate the pumping, recovery and multiple pumping operations during use to restore its stress state in actual circulation and use.

 

Introduction to common air tightness test methods

For inner bag vacuum bottles, the following typical test methods can be used to verify its air tightness:

*Pressure Hold Method: Fill the bottle with air or nitrogen at a certain pressure, and after sealing, detect whether the gas leakage exceeds the standard within a specified time.

*Bubble Leak Test: Place the sealed bottle in water and apply negative pressure to the pump head or bottle cap to see if bubbles are generated to determine the leak point.

*Vacuum Decay Test: Simulate the vacuum environment in the bottle during use to detect whether the inner bag produces pressure changes within a certain period of time.

*Burst Test: Test whether the bottle can maintain integrity under extreme pressure, which is used to evaluate stability under extreme transportation conditions.

 

Main media and standards for barrier performance testing

Barrier performance usually revolves around the following media:

*Oxygen Transmission Rate (OTR): Affects oxidation-sensitive ingredients such as vitamins and essential oils.

*Water Vapor Transmission Rate (WVTR): Critical for water-containing emulsions and gel products.

*Odor and aroma (Aroma Barrier): Prevent external odors from penetrating or internal fragrances from volatilizing, affecting the user experience.

* Bacterial/Microbial Barrier: This is especially important for products that are sensitive to the amount of preservatives used.

* UV Blocking: Certain photosensitive ingredients such as retinol and VC need to be protected from degradation by UV exposure.

During the test process, a film barrier instrument is usually used to measure the multi-layer material structure separately, such as through international standards such as ASTM F1927 and ISO 15105.

 

The enhancement of barrier properties by multi-layer structure

Inner bag vacuum bottles often use multi-layer co-extrusion technology to build the bottle body. Typical structures include:

* PP/PE structure: economical and practical, basic barrier capacity.

* PP/EVOH/PP structure: EVOH layer provides excellent gas barrier properties and is often used in high-demand formulations.

* PETG/PET/PETG structure: high transparency, suitable for high visual display requirements.

Material selection should be considered in combination with factors such as product type, transportation cycle, and required storage time. Through multi-layer combination, a balance between barrier properties, mechanical strength and chemical resistance can be achieved.

 

Aging test and long-term stability observation

The barrier and airtightness test is not a one-time assessment, but should also include the following long-term observation mechanisms:

*Accelerated aging test: Test the aging speed and stability of materials in extreme environments such as high temperature, high humidity, and high pressure to simulate the status of the product in the actual storage and transportation cycle.

*Refrigerated/high temperature cycle test: Simulate the impact of seasonal changes or logistics storage environment on bottle performance.

*High and low pressure alternating simulation test: Used to test the pressure resistance of bottles in plateau or aircraft cargo hold transportation environments.

*Content change tracking: Evaluate the packaging protection effect on the contents through the oxidation index, pH, odor, color changes of the samples in the bottle.

 

Sealing failure analysis in actual applications

Despite strict testing, there are still some common failures that deserve attention:

*Aging of pump head seal: When the frequency of use is high, the seal may deform or wear, causing air leakage.

*Stress cracking of inner bag material: Microcracks and air permeation due to material matching or extrusion process defects.

*Loosening of the interface between the bottle and the pump head: The interface is prone to loosening during repeated twisting, and the airtightness performance is reduced.

These problems can usually be alleviated by improving injection molding accuracy, using more elastic seals and improving structural design methods.

 

Development trend of airtightness and barrier test standards

As the global requirements for packaging sustainability and safety increase, airtightness and barrier tests will show the following trends in the future:

* Multi-standard parallelization: such as meeting ASTM, ISO and EU EN standards at the same time.

* Automation and dataization: The test equipment is smarter and can generate leakage curves and permeation rate maps in real time.

* Complex test environment simulating actual scenarios: such as combined testing with transportation vibration and temperature fluctuations.

* Systematic evaluation of formula adaptation: Combine packaging testing with content stability testing to comprehensively judge packaging adaptability.

 

Systematic guarantee path for packaging safety

The airtightness and barrier performance of the inner bag vacuum bottle are not only a reflection of the physical structure of the packaging, but also the core elements that support its safe use in skin care products, cosmeceuticals, and bioactive products. Through systematic testing, standardized operations and material structure optimization, manufacturers can more accurately judge whether the product can maintain the stability, safety and user experience of the contents during the actual circulation cycle. At the same time, these performance indicators are also an important technical support for promoting the trend of green, low-corrosion and environmentally friendly packaging.

 

Explore the development direction of inner bag vacuum bottles in the trend of sustainable packaging

Sustainable packaging becomes a new focus of the cosmetics industry

With the improvement of environmental awareness and the advancement of global green transformation, the cosmetics packaging industry is facing systematic adjustments. Consumers no longer simply focus on the efficacy and brand of the product, but are also increasingly concerned about whether the packaging is environmentally friendly, recyclable, and eco-friendly. Against this background, the inner bag vacuum bottle, which has the advantages of isolation protection and precise measurement, is also entering a new stage of sustainable development.

 

Basic structure and material status of the inner bag vacuum bottle

The inner bag vacuum bottle is generally composed of an outer shell, an inner bag, and a pump head. The bottle body material is mainly thermoplastic plastics such as PP, PET, PETG, and PE. The inner bag part mostly uses PE/EVOH co-extruded film, which has good oxygen barrier and chemical resistance. At present, although the product has high functionality, its material structure is complex and difficult to recycle, which has always been the key difficulty in the reform of environmentally friendly packaging.

 

The connotation of sustainable packaging and the challenge to vacuum bottles

Sustainable packaging not only refers to recyclability, but also includes resource conservation, carbon footprint reduction, green manufacturing process and other aspects. For the inner bag vacuum bottle, the challenges faced mainly include:

*The composite structure of multiple materials makes it difficult to identify and separate the recycling system.

* Some plastics reinforced with additives cannot be degraded or reused in the traditional recycling system.

* The vacuum pump has a complex structure, which is not conducive to decomposition or disassembly for recycling.

* It is impossible to achieve filling and reuse, forming a one-time consumption model.

These problems require producers to start from the design end and promote the concept of "reduction, simplification, reusability, and remanufacturing".

 

Transition from traditional plastics to recyclable materials

The first step to promote the sustainability of vacuum bottles with inner bags is material substitution. Some companies have begun to adopt the following strategies:

* Use a single material structure (mono-material), such as a full PP structure bottle + inner bag, to facilitate unified recycling and classification.

* Introduce recyclable PETG or rPET for pump body and shell to improve overall recyclability.

* Develop bio-based PE/PLA inner bag materials to reduce dependence on petrochemical resources and reduce carbon emissions.

* Reduce or cancel the use frequency of **non-degradable multi-layer barrier films (such as EVOH)** and turn to transparent oxygen barrier materials or new nano-barrier coatings.

Although these material solutions are still in the early stages of promotion, they provide a feasible path for sustainable direction.

 

Reduce the number of parts and improve disassembly

Optimizing product structure is not only conducive to energy saving in production, but also convenient for later classification and recycling. Specific strategies include:

* Modular design of pump body: Design the pump head as a disassembled component to facilitate classification before recycling.

* Eliminate metal spring: Replace metal spring with elastic plastic to avoid the barrier of mixed recycling of multiple materials.

* Use bite buckle structure instead of hot melt or bonding to make disassembly easier.

* Simplify the interface between bottle cap and pump nozzle, and reduce the use of rubber rings or accessories.

Structural simplification can also drive production efficiency improvement and transportation cost reduction, and also has cost control value for enterprises.

 

Promoting the feasibility exploration of reusable mode

In addition to the green improvement of disposable packaging, promoting the repeated filling and use of inner bag vacuum bottles is also an important development direction:

* Develop a replaceable inner bag system to realize multiple recycling of the outer shell and pump body.

* Promote the sales model of **"refill pack + empty bottle"** to reduce overall packaging waste.

* Design a transparent observation window and "filling prompt line" to enhance the user experience.

The promotion of reuse still needs to solve practical problems such as the safety and hygiene of inner bag materials, aseptic filling process, and consumer acceptance.

 

Establishment and practice of packaging carbon footprint assessment system

Quantifying sustainable performance is an important part of achieving green transformation. Enterprises can establish assessment standards in the following ways:

*Analyze the energy consumption and carbon emissions of packaging from raw material mining to final disposal through "Life Cycle Assessment (LCA)".

*Develop a carbon labeling system to publicly disclose packaging carbon emission intensity and energy saving data.

*Access third-party environmental certification systems (such as Cradle to Cradle, ECOCERT, Blue Angel, etc.) to establish a traceable environmental chain.

Using data tools to quantify the packaging carbon footprint of inner bag vacuum bottles can provide a scientific basis for subsequent material selection and design improvements.

 

Changes in consumer behavior promote green packaging transformation

In recent years, consumers' preference for environmentally friendly and low-carbon packaging has become increasingly obvious. If cosmetics brands can reflect sustainable attributes in inner bag vacuum bottles, they can often gain higher market recognition. Specifically:

* Favor products with "recyclable materials" and "low carbon footprint" labels.

* Willing to participate in programs such as "empty bottle recycling" and "refill discounts" provided by the brand.

* Expressed interest in reusable structures, believing that they reflect brand responsibility.

When promoting green packaging, companies should take into account environmental performance and usage experience, and guide consumers to establish good usage habits.

 

Policies and industry standards guide the direction of green packaging

Against the background of changes in the global policy environment, countries have successively issued environmental protection requirements for packaging materials:

* The EU "Green Agreement" clearly prohibits multi-layer inseparable plastic packaging.

* China's "Plastic Pollution Control Action Plan" proposes to gradually restrict the use of non-environmentally friendly plastics.

* Major beauty retailer platforms have also gradually established a green rating system and put forward new requirements for suppliers' environmental performance.

As a frequently used and high-tech packaging form, the inner bag vacuum bottle also needs to respond to policy adjustments in a timely manner to ensure that the product meets future regulatory trends.

 

The integration direction of sustainability and functionality

Looking to the future, the development of the inner bag vacuum bottle will revolve around the following aspects:

* Material side: transition to recycled materials and biomaterials, and strengthen single structural design.

* Design side: Optimize around reduction, modularization and multiple use.

*System side: Build a closed-loop recycling system from production, circulation to consumption and recycling.

*Brand side: Promote the combination of environmental protection concepts and consumer emotional resonance to enhance product added value.

Without sacrificing product sealing, barrier properties and user experience, promoting inner bag vacuum bottles to a greener and more sustainable direction is a key link in the cosmetics industry to achieve packaging innovation.