Barrier properties, heavy metals, coefficient of friction, tensile strength and elongation at break, appearance, heat resistance, cold resistance, pH value, total bacterial count, total mold and yeast count, compatibility, peel strength, heat-sealing performance, sealing and leak-tightness, impact resistance, thickness, residual solvent, print quality, and more.

I. Cosmetic Transportation Packaging Testing

For cosmetics to reach consumers in perfect condition after undergoing transportation, shelf display, and other stages, they require robust shipping packaging. Currently, corrugated cardboard boxes are the primary type of shipping packaging used for cosmetics, and the main testing indicators focus on the box’s compressive strength and stacking tests.

1. Carton Compression Strength Testing: During the test, place the corrugated carton between the two pressure plates of the XYD-15K carton compression testing machine. Set the compression speed and start the test. The pressure at which the carton collapses is defined as its compression strength, expressed in kilonewtons (kN). When conducting carton compression strength tests, be sure to follow the testing standards and set the pre-compression value accordingly—typically 220 N—before starting the test.

2. Carton Stacking Test: During storage and transportation, cartons need to be stacked. The cartons at the bottom layer must withstand the pressure exerted by multiple cartons above them. To prevent collapse, the cartons must have adequate compressive strength after stacking. Therefore, it is crucial to conduct both stacking tests and maximum crush-force tests.

II. Quality Inspection of Cosmetic Packaging Printing

To ensure cosmetics have appealing visual aesthetics, they are all printed with exquisite detail; thus, testing their print quality becomes particularly important. Currently, the standard tests for cosmetic print quality include evaluating the abrasion resistance (scratch resistance) of the ink layer, assessing adhesion strength, and conducting color discrimination tests.

1. Abrasion Resistance Testing: Prepare test specimens according to GB7706 specifications, then secure them on the testing plane of a friction testing machine. Attach 80 g of clean offset paper to the weight block. After setting the number of friction cycles, start the test (typically 40 reciprocations). Finally, evaluate the print quality by measuring the change in density before and after the test. Generally, a density change greater than 70% is used as the criterion for passing the test.

2. Adhesion Test for Ink: For plastic printing, the test shall be conducted in accordance with the GB7707 standard. First, adhesive tape is applied to the ink-printed surface. Then, the sample is repeatedly rolled three times on the YGJ-02 adhesive tape rolling machine. After leaving it for 5 minutes, the sample is clamped onto the A disc of the BLJ-02 disc peel tester, while the exposed portion of the adhesive tape is fixed onto the B disc. The tester is then started, and the A disc rotates at a speed of 0.8 m/s to peel off the glass adhesive tape. The condition of the ink layer being peeled off from the substrate is observed, and based on this, the adhesion strength of the printed ink layer is determined.

3. Color Discrimination: People typically observe colors under daylight. In industrial production, where precise color discrimination is required, the lighting source must have a spectral power distribution that closely resembles that of natural daylight—specifically, the D65 standard light source as defined by the CIE. During the color-matching process, a peculiar phenomenon often occurs: under one particular light source, the sample and the test specimen may appear to have the same color, yet under a different light source, they exhibit noticeable color differences—a phenomenon known as metamerism. Therefore, when selecting a standard light box, it is essential to ensure that it is equipped with dual light sources.

3. Testing of cosmetic adhesive labels

Adhesive labels are widely used in cosmetic packaging. The testing items for these labels primarily focus on evaluating the adhesive performance of the adhesive labels themselves (whether they are pressure-sensitive adhesives or self-adhesive labels). The main testing indicators include initial adhesion, sustained adhesion, and peel strength (peel force).

1. Initial Adhesion Test: The inclined plane rolling ball method is employed. In this test, the initial adhesion of the sample is evaluated by observing the adhesive force exerted by the adhesive tape on a steel ball as the ball briefly contacts the adhesive surface of the pressure-sensitive tape under slight pressure. The initial adhesion performance of the adhesive is characterized by the largest steel ball number that can be retained by the tape.

2. Adhesion Retention Performance: A test plate with an adhesive sample attached is vertically suspended from the upper and lower ends of a testing frame, with weights of specified mass hung at the bottom. The adhesion retention performance of the pressure-sensitive label is characterized by either the amount of displacement of the adhesive sample after a certain period of time or the time it takes for the sample to completely detach.

3. Peel Strength: Peel strength is an important indicator for measuring the adhesion performance of pressure-sensitive labels. Cut the pressure-sensitive labels into 25 mm wide strips using a sampling knife. Then, use a standard roller to press the labels onto a standard test plate. Next, pre-peel the sample from the test plate. Place the test plate and the pre-peeled label separately into the upper and lower or left and right grips of an intelligent electronic tensile testing machine or an electronic peel testing machine. Set the test speed at 300 mm/min, start the test, and record the final peel strength in kN/m.

4. Barrier Performance Testing of Cosmetic Packaging

The barrier performance of packaging is one of the crucial testing items for cosmetic packaging. Barrier properties refer to the ability of packaging materials to resist the permeation of gases, liquids, and other substances. Barrier performance is a key factor influencing the quality of products throughout their shelf life.

Unsaturated bonds in cosmetic ingredients are highly susceptible to oxidation, which can easily lead to rancidity and spoilage. Loss of moisture can cause cosmetics to dry out and harden. Moreover, maintaining the fragrance of cosmetics plays a crucial role in their sales. Barrier performance testing involves evaluating the ability of cosmetic packaging to prevent the permeation of oxygen, water vapor, and aromatic gases.

1. Oxygen Permeability Testing: This test primarily measures the oxygen permeability of thin films, composite films, and the overall packaging—such as cosmetic bags or bottles—used for cosmetic packaging. The pre-treated sample is clamped tightly between two test chambers. Oxygen or air flows on one side of the film, while high-purity nitrogen flows on the other side. Oxygen molecules diffuse through the film into the high-purity nitrogen on the opposite side and are carried by the flowing nitrogen to a sensor. By analyzing the oxygen concentration measured by the sensor, the oxygen permeability rate can be calculated. The testing principle for packaging bags or bottles is similar.

2. The water vapor transmission rate test is primarily used to determine the water vapor transmission rate of packaging film materials as well as packaging containers such as bottles, bags, and cans used for cosmetics. By measuring the water vapor transmission rate, it becomes possible to control and adjust the technical specifications of packaging materials and other related products, thereby meeting the diverse requirements of product applications. The sample is clamped between two test chambers; a stream of nitrogen with a stable relative humidity flows on one side of the film, while dry nitrogen flows on the other side. Due to the humidity difference, water vapor migrates from the high-humidity side through the film to the low-humidity side. The water vapor that passes through to the low-humidity side is carried by the flowing dry nitrogen to a sensor, which then outputs an electrical signal. From this signal, the amount of water vapor transmitted can be calculated. For packaging containers such as bottles and bags, dry nitrogen flows inside the container, while the outer surface of the container remains in a high-humidity environment.

3. Fragrance Retention Performance Testing: This indicator is particularly important for cosmetics, as the loss or alteration of a cosmetic’s fragrance can significantly impact product sales. Therefore, it is crucial to test the fragrance retention performance of cosmetic packaging. Under specified temperature conditions, a sample is used to separate two chambers: one side is exposed to a high concentration of aromatic gas, while the other side is at a lower concentration. This creates a concentration gradient of aromatic gases across the sample. The aromatic compounds then permeate through the film into the low-concentration side and are carried by a carrier gas flow into the separation chamber. The FID hydrogen flame ionization detector is employed to measure the concentration of aromatic gases in the carrier gas, thereby enabling the calculation of the amount of aromatic gas that permeates through a unit area of the sample per unit time.