A. Shrinkage test
1) Purpose: To determine the dimensional stability of woven or knitted fabrics after repeated washing in a household washing machine.
2) Principle: Before washing, mark the size on the specimen, and judge the size change of the specimen by measuring the change of the mark after washing.
3)Process: Select the washing and drying method, cycle and drying times according to the cloth type and customer's requirements, add standard detergent and appropriate water level to start washing and drying, and finally get the test results.
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B. Physical property test
1) Main items:
Yarn count, density, gram weight, tensile strength, tear strength, seam slip, seam strength, top breaking strength, abrasion resistance, pilling resistance, etc.
2) Specific description:
Yarn count: refers to the thickness of the yarn, most of them are currently used in imperial count, expressed in Ne, which is defined as a multiple of 840 yards of the length rate of 1 pound of cotton yarn at a metric moisture return rate of 9.89%.
Density: The number of yarns per INCH.
Grammage: Ounce weight per square yard of fabric or gram weight per square meter of fabric.
Tensile Strength: The force used when a fabric of a certain size is stretched by a tensile strength machine at a constant rate until it breaks is the measured tensile strength. The test of tensile strength has grab sample method and strip sample method, according to different test standards and customer requirements to choose the specific test method.
Tearing strength: a certain size of specimen, clamped on the tearing strength instrument, cut all the mouth in the middle to determine the direction of tearing, tearing strength instrument using a pendulum to drop the specimen from the cut to tear the force used is the measured tearing strength.
Seam slip: After folding the fabric of a certain size, stitching along the width direction, cutting a certain distance away from the seam line, using the tensile strength meter with a constant rate of stretching to a certain seam opening force or stretching to a certain strength when the opening distance, is the seam slip we measured. The seam slip can be measured in two ways: constant opening force and constant force opening. Seam slip is generally only used for woven fabric testing.
Seam strength: the same as the seam slip, a certain size of fabric folded, along the width of the direction of the stitch, a certain distance from the seam line cut, the use of tensile strength instrument with a constant rate of stretching so that the force used to break the seam line is the measured seam strength, seam strength can be carried out at the same time with the seam slip, generally only for the test of woven fabrics.
Top breaking strength: Under certain conditions, a flat fabric in a suitable angle spin plus an expansive expansion force, until it breaks, this force is the top breaking strength.
Abrasion resistance: Under the known pressure, the sample mounted on the specimen clip and the standard abrasion cloth rub each other under a certain pressure with a certain track, until the fabric appears the number of broken yarn or holes required by the customer, record the number of abrasion at the end of the experiment, which is the measured abrasion resistance value.
Pilling resistance: the fabric will be rolled and rubbed under specific conditions for a certain period of time to see its surface pilling and pilling, pilling refers to the formation of fiber entanglement of pompom clusters on the surface of the fabric. Pilling refers to the fabric surface fiber rough uneven and (or) fiber pilling, resulting in changes in the appearance of the fabric, its pilling is assessed by rating sample photo or original sample comparison.
C. Color fastness test
1) Main items:
Washing color fastness, dry cleaning color fastness, rubbing color fastness, sunlight color fastness, sweat color fastness, water color fastness, chlorine bleaching color fastness, non-chlorine bleaching color fastness, hot pressing color fastness, etc.
2) Basic content:
Washing color fastness: the specimen is sewn together with the standard lining fabric, washed, cleaned and dried, and washed under suitable temperature, alkalinity, bleaching and rubbing conditions, so that the test results are obtained in a shorter period of time. The friction effect is done by small bath ratio and the appropriate number of stainless steel beads tumbling, impact, and finally the standard post lining fabric and specimens are rated with a special gray card for color fastness to get the test results. Different testing methods have different temperature, alkalinity, bleaching and rubbing conditions and specimen size, the specific ones should be selected according to the testing standards and customer requirements. The colors with poor color fastness in general washing are emerald blue, bright blue, black big red, navy blue, etc.
Dry cleaning color fastness: the same as the color fastness of washing, but the water washing to dry cleaning.
Rubbing color fastness: the specimen on the rubbing fastness meter, in a certain pressure with the standard rubbing white cloth and rubbing a certain number of times, each group of specimens need to do dry rubbing color fastness and wet rubbing color fastness. The color stained on the standard friction white cloth with gray card rating, the resulting grade is the measured friction color fastness. Fastness to rubbing needs to do both dry and wet rubbing test, all the colors on the specimen to rub to.
Sunlight fastness: textiles are usually exposed to light when in use, light can destroy the dye and lead to the well-known "fading", so that the colored textiles discoloration, generally lighter, darker, some will also appear color light change, so the need to test the color fastness, sunlight fastness test, is the specimen with different fastness Levels of blue wool standard cloth together in the specified conditions for sun exposure, the sample and blue wool cloth for comparison, assess the light fastness, the higher the blue wool standard cloth level of light resistance.
Sweat stain color fastness: the specimen and the standard lining fabric are sewn together, put in the sweat stain solution after treatment, clamped on the sweat stain resistance color fastness meter, put in the oven at a constant temperature, then the specimen of the lining fabric are dried separately, and finally the standard post lining fabric and the specimen are rated with the special gray card for color fastness to get the test results. Different test methods have different ratios of perspiration solution, different sample sizes, different test temperatures and times.
Water stain color fastness: the specimen and standard lining fabric sewn together, placed in certain conditions of water after full immersion, clamped on the sweat stain resistance color fastness meter, put in the oven at a constant temperature, and then the specimen lining fabric dried separately, and finally the standard lining fabric and specimens with color fastness special gray card rating, to get the test results. Different test methods have different sample sizes, different test temperatures and times.
Chlorine bleaching color fastness: the fabric in the chlorine bleaching solution according to certain conditions after washing, assess the degree of color change, which is the chlorine bleaching color fastness.
Non-chlorine bleaching color fastness: the fabric will be washed under the washing conditions with non-chlorine bleaching, assess the degree of color change, which is non-chlorine bleaching color fastness.
Hot pressing color fastness: the dry specimen covered with cotton lining fabric, in the prescribed temperature and pressure of the heating device under pressure for a certain period of time, and then use the gray sample card to assess the color change of the specimen and the lining fabric staining. Hot pressing color fastness has dry pressure, tide pressure, wet pressure, the specific customer requirements and test standards according to different test methods.
D. Chemical performance test
1)Main test items:
Formaldehyde test, pH test, water repellency test, oil repellency test, anti-fouling test, flame retardant test, fiber composition analysis, azo dyes prohibited test, etc.
2) Basic content:
Formaldehyde test: through a certain way to a certain amount of free formaldehyde or released formaldehyde in the fabric extracted, and then through the colorimetric test, to calculate the formaldehyde content.
In the market now, textile products can be finished by resin to improve the wrinkle resistance of the product, this resin finishing agent is directly synthesized by formaldehyde, so after these resin finishing of the fabric will be a certain amount of formaldehyde residue. In addition, in order to improve the fastness of dyeing, coating printing paste in the cross-linking agent and direct dyes and reactive dyes used after dyeing the fixing agent, etc. will make a certain amount of formaldehyde residue on the clothing material. These formaldehyde can be measured by certain test methods.
pH test: The acidity and alkalinity of the fabric solution is measured precisely with a pH meter. The value read out on the pH meter is the measured pH value.
Water, oil and stain resistance test: The resistance of the fabric to water, oil and stains is measured in a certain way, mainly for the fabric type that has undergone three anti-flame finishing.
Flame retardant test: the specimen will be put on the flame retardant tester for burning according to the regulations, to see its flame spread time.
Fiber composition analysis: first of all, the qualitative analysis of the fiber of the fabric, qualitative analysis has a variety of burning method, melting point method, hand visual inspection method, microscope slice analysis method, etc., the general use of microscope slice analysis method, that is, the slicer will be observed under the microscope after the fiber slice, according to its external appearance, determine the fiber type, and then according to the different fibers with different solvents for qualitative analysis, to calculate the specific composition of content.
Azo dyes test: It is the most important quality control item in the international textile and apparel trade and one of the most basic quality indicators of eco-textile, which is mainly analyzed by gas chromatography. Azo dyes test is divided into three methods, textiles (textiles other than polyester and leather), polyester (polyester), leather (leather), so when doing azo testing must provide the composition of the product.