Fabric Sample Cutting Machine

As living standards rise, so does the importance of protecting the environment. A new idea, ‘green consumption,’ has taken hold. It now controls the safety and environmental standards of clothing fabrics. The safety and environmental protection indexes of textiles include many items. The pH value of textiles is one of them. With the rise of consumer awareness, it is now a focus for manufacturers and businessmen.

1. What is the pH value in garments?

The pH value in clothing measures its residual acid and alkali. It comes from testing the pH of a water extract of the fabric. This is a key test to control acidity and alkalinity in the production process.

pH ranges from 0 to 14. pH=7 is neutral. pH<7 is acidic; the lower the value, the stronger the acidity. pH>7 is alkaline; the higher the value, the stronger the alkalinity.

2. Where does the pH value come from?

The chemical treatment in clothing production is extensive. It includes fiber production, pulp dyeing, printing, and washing. These processes require a lot of soda ash, caustic soda, pH adjusters, and surfactants. They also depend on the fabrics, tissue specs, and the equipment used. A particular issue is the washing (neutralization) process. It is often not thorough enough, leaving acid and alkali residues in the fabrics. Alkali residues.

3. Textile pH exceeds the standard reasons

The influence of dyestuff in production

Manufacturers produce commonly used reactive, serin, and sulphur dyestuffs under alkaline conditions. The pH of the water used in production will affect the cloth, even if we wash and treat it well.

Influence of printing and dyeing process

Cotton, wool, silk, polyester, polyamide, and acrylic are textiles. Refining, dyeing, and printing process them. They may have residual alkali, acids, and additives, with varying pH levels. Washing, soaping, acid neutralization, and drying treat the fabrics. But, if chemical additives are high or washing is poor, the pH may exceed the standard. This can affect the textiles’ performance.

Influence of fabric

The fabric’s thickness affects its surface pH. Thin fabrics are easy to wash after dyeing, and have a low pH. Thick fabrics are harder to wash after dyeing, and have a high pH.

Influence of operation error of laboratory personnel

The pH of the cloth will vary with:

①The test fabric’s dryness and humidity.

②The extraction temperature.

③The extraction time.

4. Hazards of excessive pH value

Normal human skin has a pH of 5.5-6.5. It is weakly acidic due to a chemical reaction. The skin’s sweat glands and sebaceous glands secrete sweat and oil with a pH. A large pH difference between the outside world and the body can cause discomfort and skin diseases. This need forms the basis for the pH test for textiles. If the pH value of clothing is too high or low, it can harm the skin. This can stimulate the skin, causing a burning sensation. It can also breed bacteria and cause diseases.

5. pH standard test and its differences

Chinese standard (GB/T7573-2002)

Weigh three copies of a 2 ± 0.05g sample. Cut it into 5 × 5mm pieces. Put them in a flask with 100ml of distilled water or a 0.1mol/L potassium chloride solution. Shake the flask to wet the specimen. Then, oscillate the flask for 1 hour. Use a pH meter to measure the pH of the water extract at room temperature (without fabrics). Test each sample three times. Use the average of the second and third tests as the final result, accurate to 0.05.

European Union Standard (EN1413-1998)

Weigh three 2 ± 0.05g samples. Cut each into 5 × 5mm pieces. Place them in a flask with 100ml of a 0.1mol/L potassium chloride solution or 100ml of distilled water. Shake the flask to wet the samples. Then, place it on an oscillator for 2 hours at room temperature. Use a pH meter to measure the pH of the water extract (excluding the fabric). Test each sample three times and average the results of the second and third tests. Report the final result to 0.05. We took the average of the results of the second and third specimens as the final result, accurate to 0.1.

Japanese Standard (JISL1096-1999)

Weigh a 5±0.1g sample. Cut it into 10×10mm pieces. Boil it in 50ml distilled water for 2 min. Put the sample into a flask. Shake the flask to wet the sample. Let it stand at room temp for 30 min. Remove the sample. When the water extraction solution reaches 25±2℃, use a pH meter to measure its pH, accurate to 0.1.

American standard (AATCC81-2001)

Weigh a 10 ± 0.1g sample. Cut it into small pieces. Boil it in 250ml of distilled water for 10min. Put the sample in a flask and shake it to fully wet it. Boil for 10min, then cool to room temperature. Remove the sample. Use a pH meter, accurate to 0.01, to measure the pH of the aqueous extract.

6. pH sampling rules

The following rules apply to the sampling of formaldehyde, pH and azo test:

For products with colour patterns, cut and mix as one sample.

For products with a regular pattern, we sample cyclically. It requires cutting and mixing into one specimen.

For products with a large pattern cycle, sample based on the ground and flower area. Cut and mix these into one sample.

For independent patterns of products, the pattern area can meet a sample. The pattern of a separate sample must be very small, less than a sample. The sampling should include the pattern. Someone must not cut it from several samples and then combine it into a sample.

Only small patterns shall detect carcinogenic aromatic amine dyestuffs.

For products that can be manually layered, take samples in layers. Measure them separately.

We sample products that cannot be manually stratified as a whole.

7. pH sampling equipment process

The SmartCut intelligent cutting system can scan a barcode. It then reads the test item’s information. Next, it scans the item’s graphics. A unique algorithm lays them out per the standard requirements. The system projects the layout on the fabric. The smart cutting machine uses this to cut the fabric. It also marks the sample based on the customer’s settings. The technician cuts the sample to be examined into a square measuring at least 30cm x 30cm, per the standard.

The ProPress sample cutting machine cuts the sample into 5x5mm pieces in seconds. It controls the pressure on a precision die to cut the sample in a single pass. It does this automatically and accurately. This precision allows for more reliable tests for formaldehyde, pH, and more. Efficiency increased by more than 80%, 6 times more than manual cutting. To test for formaldehyde, pH, azo, heavy metals, and other substances in fabrics, leather, and flexible plastics.

Lay the samples flat on the material tray. Start the machine with both hands. Someone will pull in the tray. The ProPress will punch and cut the samples. It will then push out the finished samples. The machine has a strong air cleaning system. It can blow away all fibres and fragments left by punching and cutting. This ensures no mixing between the samples.

Introduction to the ProPress Sample Punching and Cutting Machine:

ProPress punches and cuts the sample into 3x3mm fragments in 8 seconds. It’s fully automatic and can cut multiple layers of fabric at once. Servo-driven, quiet and friendly. You can easily install it and use it on site without air and oil pressure. You can use the small size directly on the worktable. It is for punching and cutting test samples of textiles, yarns, leathers, and plastics. These are all flexible materials. It tests for formaldehyde, pH, azo, and heavy metals. Someone lays the samples flat on the tray for punching. The operator starts the machine with both hands. Someone pulls in the tray. The ProPress automatically punches the samples and then ejects them. The operator then pours the samples from the tray into the collection box. Once you remove the tray, the machine turns on a strong air cleaner. It blows away any fibres and debris left by the punching process. This prevents the samples from mixing. The operator can see any residue on the screen via the instrument’s HD camera. They can then manually restart the cleaning process.

Also, the ProPress ensures your safety. It has:

Two-handed button activation,

An enclosed work area with safety grids, and

A flashing light beam to alert you to its operation and prevent injury.

Introduction to SmartCut Fabric Sample Cutting Machine:

The SmartCut system samples fabrics in less than 3 minutes. It has built-in, smart sample cutting software. It offers various cutting patterns and sizes. You can select them based on project or test standards. You can save the selections as a template for easy access next time. The cutting software will layout the project’s test graphics. It will use a unique algorithm to meet the standard requirements. It will then project it on the fabric. The cutting machine will cut the fabric samples per the projection. It will also make various markings on the samples as per the customer’s settings. And it applies to dozens of tests, like pilling, tearing, and water repellency. It supports GB/T, FZ/T, ISO, EN, JIS L, AATCC, ASTM, CAN, AS, and other standards.

Application of ProPress Sample Cutting Machine :

Many applications use specimen punching and cutting machines. They test flexible sheet materials, such as textile fabrics, leather, and plastics. They are also used in the biochemical, pharmaceutical, food, and chemical industries.

Specimen punching and cutting machines work with flexible sheet materials. These include textile fabrics, leather, and plastics. They are mainly used to punch and cut test samples for formaldehyde, pH, azo, and heavy metals. For example, ProPress machines can quickly make test samples. They save time and ensure quality. In biochemistry, pharmacy, and food and chemical industries, researchers use them to homogenize samples, such as cells and proteins. They also mix medicines and ingredients to improve experiments and sample handling.

Sample preparation machines have three key features. They prepare samples quickly, are safe to use, and meet international standards. Pneumatic punching and cutting specimen makers are for plastic, rubber, paper, and fabric laminates. They have safety guards around the cutting bed to ensure safe operation. They can make specimens of any shape and size to meet any international standard. These features make the machine vital in labs and industry. They enhance efficiency and ensure accurate, reliable results.

Application of SmartCut Fabric Sample Cutting Machine:

The SmartCut Textile Sample Cutting Machine saves 90% of sample cutting time. It speeds up the entire test. The cutting is precise and the sample qualification rate is higher. The sample graphic library covers more than 95% of the textile testing items. It meets most tests for abrasion, pilling, tearing, waterproofing, anti-static, tensile strength, and color fastness. A flexible cutting pattern makes sampling easier. This Textile Sample Cutting Machine can do three types of cutting. It can cut different fabrics at the same time (multi-station cutting). It can cut up to 7mm thick (multi-layer cutting). And it can cut irregular shapes (shaped cutting). It has sample-cutting software, a cutting machine, a computer, and a projector. The working principle: The operator designs cutting samples in the software. The projector projects the layout onto the working table. After starting, the fabric sample cutting machine will cut the samples as required.

ProPress Specimen Punching and Cutting Machine Benefits:

More accurate sample preparation for more reliable test results. Manual cutting of samples can cause large differences in shape and size. This can lead to poor dissolution and inaccurate test data. ProPress cuts samples by stamping, which is precise and fast. The consistent samples make tests for formaldehyde and pH more reliable. ProPress saves labs over 80% of sample prep time. It takes only 8 seconds per operation, vs. at least 60 seconds for manual cutting. It is vital for large-scale labs that need to prepare many samples daily. The ProPress has a self-cleaning system. It blows air to remove any debris from cutting. And it also has a built-in HD camera (2MP, 1920×1080). It observes the cleaning and cutting to ensure no samples mix.

Advantages of the SmartCut system:

Strictly according to the standard sampling, so that the test is more reliable. It supports dispersed, trapezoidal, full-width, and 45° sampling. It can also sample based on the alignment, grid, and edge-to-edge rules. Ensure the reliability of the test from the sample source. The tungsten steel blade of SmartCut is sharp and can rotate 360°. It has a cutting accuracy of 0.1mm. The error rate for round-trip cutting is less than 0.01mm. It can cut grams of specimens accurately. For large-scale laboratories to save 5 labour per year (about 420,000 yuan). To cut 100 whole samples per day, the old way takes 3,000 minutes, or 6 workers. The SmartCut system needs only 0.6 workers to cut those samples. This saves 5 workers a year for the lab. And SmartCut can also be multi-station cutting (cutting different fabrics at the same time), multi-layer cutting (maximum cutting thickness of 7mm, can cut 1-20 layers), shaped cutting (irregular graphics), stacked cutting (the same samples of different tests, order consolidation, synchronous cutting); can cut most of the specimen, and marking of samples (you can mark the sample with warp and weft direction, front and back, report number, Perform shrinkage marking, etc.).

8. Processing of fabric pH adjustment

If fabrics or garments fail pH tests, adjust their pH. Most unqualified fabrics are alkaline. Many acids can adjust pH, but glacial acetic and citric acids are the most common. Glacial acetic acid is volatile and has a strong odor. Citric acid adjusts pH more stably. So, we suggest using citric acid. But, control its amount. Too much will affect the feel of the fabrics and make them less stable. Excessive amount will affect the feel, but also easy to cause yellowing.

For example, the fabric’s pH was 9-10. Adjust the citric acid solution to 4-5, then soak the fabric for 10 minutes. After that, dry it. Before sending it to the customer, send the formal testing structure. This will confirm the qualification and reduce the trade risk.

9. Textile pH test factors affecting analysis

After pre-treatment, dyeing, and finishing, the pH of the fabric will change. It will be different from the grey fabric. The pH testing data is not reproducible, especially at critical values. The sample needs retesting to ensure accuracy.

(1) GB/T7573-2009, ISO3071-2005, and AATCC81-2016 are different tests. They vary in temperature, extraction time, and sample weight. So, they give very different pH results.

(2) The extraction temperature affects the pH test. As it rises, the pH test results increase. We should watch the temperature of the extraction solution when extracting. We should also watch the testing environment’s temperature when using the pH meter.

(3) Calibrate the pH meter and check its accuracy. The glass electrode is fragile. It may give incorrect results if broken or damaged. Therefore, before the test, we must calibrate the pH meter with buffer solution. We also need to verify the instrument during the comparison.

(4) For the buffer solution, use pH 4.01, 6.86, and 9.18 as the calibration points. After three-point calibration, the linearity must be ≥ 95%. If not, recalibrate or replace the calibration buffer solution.

(5) The experimental water must meet the test requirements: conductivity ≤ 0.50mS/m, and a pH of 5.0 to 7.5. It cannot exceed these limits, as they will affect the sample’s pH.

(6) The different parts of the test sampling will have an impact on the test results. The sample has printing, embroidery, and appliquéd parts. They are different from the other parts. This is especially true after washing cotton and denim items. The sample’s pH value is not uniform. The same clothing may work differently on the front and sleeve, or on the front and back of trouser legs. We need rigorous testing. Test the parts with pleats, printing, and embroidery.

(7) The test personnel will cause differences in the operation. Their varying intensity in shaking the liquid will produce different results. In short, we must consider the above factors in testing textile pH. We must strictly control each test step. 10.

10. Ensure the qualified method of textile pH value

Dyeing and finishing process

A textile’s pH value comes from the dyeing and finishing processes. Pre-treatment, dyeing, printing, and washing all affect pH. For example, you should add a large amount of alkali to refine cotton in pre-treatment. Add acid to the carbonisation of wool. When dyeing, wool and silk are generally dyed in acid. Cotton usually needs an alkaline dye. The finishing agent must have many added finishing agents. They must have different acidities and alkalinities, and so on. So, to get a good pH in the finished extract, we must strictly control the pH in each step of the printing and dyeing. We must also improve the washing in each step of the dyeing and finishing processes.

Water washing is a process. It uses physical exchange and flushing. It removes dyes and chemicals from the fabric. These substances diffuse from the fibre pores and desorb. Then, the washing solution dilutes and removes them. This raises the fabric’s pH to a standard level. So, we want to increase the washing power of water on the fabric. We will also increase the wash water ratio. After that, we will neutralise the acid and adjust the pH to improve the fabric’s pH.

Washing bath ratio

After many production practices, the pH of dyed fabrics was more stable with a higher bath ratio. The standard deviation of pH values was lower. A smaller standard deviation means better stability. The printing and dyeing processes left many alkali molecules on the fibre. A larger bath ratio made the wash solution and alkali less concentrated. This increased energy, causing the alkali molecules to move and diffuse quickly. As a result, the wash would dilute and remove the alkali.

Acid neutralisation

After dyeing and finishing, some alkali residues remain on the fabric. This is especially true for thick, tightly woven fabrics. Alkali molecules have some affinity for the fiber. They do not easily wash out, even after mercerization. The washing solution has a high alkali concentration (sodium hydroxide at 245-300g/l). It is hard to remove the alkali. To control the fabric’s pH, use a washing solution with 0.3-0.5g/l of glacial acetic acid. 0.5g/L glacial acetic acid and 0.1-0.25g/L sodium acetate buffer solution for neutralisation.

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