How Kingyin Controls the Quality of Premium Bristles of makeup brushes

 Kingyin implements a full-process traceability system for the quality control of high-end synthetic bristles, and builds a closed-loop standard from raw materials to finished bristles, fully complying with the requirements of world-leading cosmetic brands. From raw material selection, formula modification, wire drawing to testing, all are completed in-house in Henan, ensuring controllable quality and quick response.

Raw Material & Incoming Quality Control (IQC)

1. Qualified Supplier (Fixed Vendors & Batch Traceability)

· Nylon 612 (Premium Main Material): BASF (Germany) and DuPont (USA). 100% brand-new; recycled/regrind materials are strictly prohibited.
· PBT (Antibacterial & Easy to Clean): Medical-grade PBT from BASF, high temperature resistant, oil resistant and excellent shape retention.
· Micro Bionic Ultra-fine Fiber (0.06mm grade): Custom modified fiber with bionic animal hair cuticle structure, delivering outstanding softness and powder pickup performance.

2. Raw Material Access Standards (Full Batch Inspection Mandatory)

· Suppliers must provide original COA, SGS test reports and FDA & REACH compliance certificates
· Appearance: Uniform particles, no impurities, no yellowing, no odor..
· Melt Index (MI): Nylon 612 is controlled at 25±2g/10min to ensure stable fiber drawing.
· Batch Segregation: Separate storage and dedicated usage for each material batch to avoid material mixing.

 

In-Process Quality Control (IPQC)

Fiber Drawing & Shaping (Temperature controlled within ±0.5℃ with full-process monitoring)

· Melt spinning: Precise temperature control. Nylon 612: 245±1℃; PBT: 255±1℃, to maintain stable molecular structure.
· Drawing & setting: Three-stage drawing plus high-temperature setting for highly oriented molecular chains, maximizing elasticity and toughness.
· Dust-free workshop: Class 10,000 dust-free environment throughout production to prevent contamination and guarantee pure bristles.

Grading & Sorting + Batch Traceability

· Three-level sorting: Rough mechanical sorting → optical screening → manual picking to remove defective fibers (over-thick, over-thin, bent or soiled).
· Identification & traceability: Each bristle bundle has a unique label covering raw material batch, production date, machine number and inspector ID, enabling full lifecycle traceability.

 

Final Quality Control (FQC)

1. Dimensional Accuracy (Core Technical Indicators)

· Diameter tolerance: ±0.005 mm (premium quality) / ±0.01 mm (standard quality), 100% on-line laser inspection.
· Length deviation: ≤ 0.3 mm, inspected by both manpower and machines to ensure uniform bristle shape.
· Roundness: No flat or irregular filaments with perfectly round cross-sections for skin-friendly use.

2. Physical Properties (Touch, Elasticity & Durability)

· Softness: Score ≥ 85 via pressure tactile tester, delivering squirrel-hair-like gentle touch.
· Resilience rate: ≥ 98%, no permanent deformation after 1,000 bends.
· Tensile strength: ≥ 55 N/mm², effectively preventing bristle breakage for long service life.
· Abrasion resistance: No fuzzing, breakage or deformation after 10,000 friction cycles.

3. Safety & Environmental Compliance (International Standards)

· Heavy metals: Pb ＜ 10 ppm, As ＜ 2 ppm, Hg ＜ 1 ppm (compliant with EU REACH).
· Phthalates: Not detected (DEHP/DBP ≤ 0.1%).
· Microorganisms: Total bacterial count ＜ 100 CFU/g, no pathogenic bacteria (per GB 15979).
· Sensitization test: No redness or stinging after 24-hour skin irritation test.

Limit Tests

· Shedding Test: Pull gently and apply 3M adhesive tape. Single bristle pull-out force ≥ 4N / ≥ 0.15g per test. No bristle shedding or root breakage.
· Powder Pickup Capacity: Powder pickup ≥ 0.15g per use. Even adhesion with no powder flying or caking.
· Weather Resistance: Under cyclic temperature from -20℃ to 60℃ for 48 hours, elasticity and touch remain unchanged.
· Cleaning Test: After 10 cycles of washing and drying, no deformation or tangling; resilience is fully restored.

 
Kingyin always upholds strict high-end quality standards and adopts a zero-tolerance policy towards defective products. We reject all unqualified raw materials, prevent defective semi-finished products from moving to the next process, and never ship faulty finished makeup brushes.

We also offer customized solutions for bristle material, softness, blending ratio and surface coating to meet the differentiated demands of premium makeup brands.Kingyin implements a full-process traceability system for the quality control of high-end synthetic bristles, and builds a closed-loop standard from raw materials to finished bristles, fully complying with the requirements of world-leading cosmetic brands. From raw material selection, formula modification, wire drawing to testing, all are completed in-house in Henan, ensuring controllable quality and quick response.