Custom Cosmetic Jar Manufacturers

How to design cosmetic jar to ensure good sealing

Core elements of sealing design
1. Material selection: the basic guarantee of sealing
The primary basis of sealing performance is the selection of appropriate materials. Shaoxing Roman Plastic commonly uses thermoplastics such as PP, PETG, AS, PMMA, etc. These materials have excellent performance in chemical corrosion resistance, dimensional stability and environmental protection.
Among them, PP (polypropylene) is a commonly used material in the sealing structure of the cap and inner disc due to its good elasticity and heat resistance. PETG is often used in the jar itself due to its high transparency and toughness, which can not only display the contents beautifully but also not easily break.
By testing the chemical compatibility of cosmetics with different ingredients (such as creams, facial masks, lotions) and plastic materials, Shaoxing Roman Plastic ensures that there is no migration reaction between the materials and contents of each jar, thereby improving the sealing protection ability.
2. Structural optimization: multiple sealing system design
The sealing design depends not only on the material, but also on the rationality of the structural design. Shaoxing Roman Plastic uses a variety of sealing structure designs in product development, such as:
Double-layer sealing structure: inner cover + outer cover combination design, effectively blocking air and impurities.
Screw-tightening screw cap: through high-precision injection molds, ensure that the screw cap and the bottle mouth are precisely engaged, thereby forming a mechanical locking force and improving the sealing effect.
Leak-proof sealing ring (gasket) or gasket design: used to improve air tightness, often used in high-end cans.
Vacuum design (Airless Jar): completely isolates air through air pressure or piston system, especially suitable for products containing active ingredients or preservatives.
Shaoxing Roman Plastic has more than 50 high-precision injection molding equipment, which ensures the high precision of the fit between the cover and the can body, avoiding the risk of leakage caused by tolerance from the source.
3. Balance between surface treatment and appearance sealing
In addition to functional structure, cosmetic jars also need to have visual and sensory advantages such as beauty, smoothness, and comfortable touch in the market. Shaoxing Roman Plastic is good at using surface treatment technologies such as spraying, UV coating, silk screen, hot stamping, labeling, etc., which not only improves the appearance of the product, but also enhances the sealing level of the product.
For example, in addition to giving the product a high-gloss or frosted texture, the UV coating can also form an additional layer of airtight film, which increases the antioxidant capacity and content protection capacity to a certain extent.
4. Production process control: the core of quality control
Even the best design needs to rely on high-standard production control to achieve it. Shaoxing Roman Plastic has 15 assembly and packaging production lines, and sets up strict quality inspection procedures in every link.
Including:
Sealing performance test (leak test)
Capping torque test
Drop test
Temperature and humidity accelerated aging test
Through these comprehensive testing methods, it is ensured that every Cosmetic Jar shipped out of the factory has a high level of sealing ability.
OEM/ODM sealing customization advantages
Shaoxing Roman Plastic not only provides standard products, but also provides OEM/ODM customization services to global customers for a long time. We can tailor a high-sealing Cosmetic Jar that meets the functional and aesthetic standards according to the customer's content attributes, target market (such as America, Europe, and the Middle East) and brand positioning.
We adhere to the "customer-centric" principle and participate in the packaging development of customers throughout the entire process, from product concept, 3D structure modeling, sample verification, mass production to shipment tracking, to help them transform their ideas into truly feasible packaging entities.
Insights into sealing trends in the international market
In the global cosmetic packaging trend, the sealing requirements are constantly increasing, especially in the following areas:
Natural organic cosmetics: higher sealing is required to prevent external contamination;
Non-preservative formula products: increased demand for vacuum jars and airtight packaging;
Travel and portable markets: need to take into account small volume and anti-leakage design;
Enclosed compatibility design of environmentally friendly materials: such as sealing technology upgrades after the application of green materials such as PCR and PLA.

Which types of cosmetics are suitable for the plastic materials commonly used in cosmetic jars?

PP (polypropylene) - cost-effective, suitable for creams and paste products
PP is one of the most widely used plastic materials at present, with good chemical resistance, heat resistance and toughness, and light texture and easy processing.
Application advantages:
Strong corrosion resistance, suitable for creams containing oils;
Relatively low cost, suitable for mass production of medium and low-priced products;
Support high-temperature disinfection, suitable for packaging with high requirements for hygiene conditions.
Applicable cosmetics:
All kinds of creams, body lotions
Hair masks, hair creams
Chinese medicine ointments, repair creams and other thick texture products
Shaoxing Roman Plastic has a mature mold development system and production standards for the development of PP injection molding parts, which are widely used in customers' classic cream series packaging.
PET (polyethylene terephthalate) - high transparency choice, suitable for gel and gel products
PET has excellent visual presentation with its high transparency, good mechanical strength and gloss. It is an environmentally friendly and recyclable material, which is very suitable for brands that emphasize "natural and fresh" positioning.
Application advantages:
High transparency, can intuitively show the texture of the product;
Good chemical stability, suitable for formulas with high water content;
The material is light but the structure is strong, which is conducive to portable design.
Applicable cosmetics:
Gel skin care products, eye gel
Sleeping mask, jelly mask
Highly moisturizing hyaluronic acid products
Shaoxing Roman Plastic uses a combination of precision blow molding and injection molding technology in the production process of PET cans to ensure that the bottle body has both strength and optical properties, which is especially popular with European and American customers.
PETG (modified polyester) - taking into account rigidity and toughness, suitable for high-end transparent packaging
PETG is a modified upgraded version of PET, which has better flexibility and impact resistance while maintaining high transparency.
Application advantages:
High gloss appearance, enhances high-end feeling;
Not easy to break, suitable for designing special-shaped packaging;
Excellent printing adaptability, suitable for silk screen printing, hot stamping and other processes.
Applicable cosmetics:
High-end freeze-dried powder skin care series
Water-gloss ampoules
Highly active antioxidant ingredient packaging
Shaoxing Roman Plastic has developed PETG series bottles and jars for many European and American brands, and cooperated with high-end surface processes such as UV spraying and electroplating to effectively improve the added value of packaging.
AS (Acrylonitrile-Styrene)-Hard and bright, suitable for display products
AS plastics are mostly used for structural parts of cans or shells due to their high hardness, good transparency and smooth surface, but their solvent resistance is slightly lower and they are not suitable for containing formulas with strong activity.
Application advantages:
High hardness and strong scratch resistance;
The appearance texture is close to glass, suitable for visual display;
The molding size is stable and suitable for nested structures.
Applicable cosmetics:
High-gloss display packaging (such as trial packs, gift boxes)
Outer cans/shells in multi-layer structures
Non-contact content bearing (such as sandwich design)
Shaoxing Roman Plastic's experience in AS injection molding ensures the consistency of appearance and is often used in high-end skin care gift box sets.
PMMA (Acrylic) - the first choice for glass replacement, suitable for luxury products
PMMA, also known as organic glass, is widely used in high-end cosmetic packaging for its excellent optical properties and luxurious feel. It can achieve a glass-like visual texture and has better impact resistance.
Application advantages:
The light transmittance is as high as 92%, presenting a "crystal clear" texture;
Strong structural rigidity, suitable for thick-walled design;
Often paired with liner structure to improve sealing and compatibility.
Applicable cosmetics:
High-end anti-aging cream, luxury night repair cream
Limited edition skin care series
Gift box single product display bottle
Shaoxing Roman Plastic is good at combining thick-walled PMMA with PP liner to achieve the dual standards of visual beauty and functional safety.