Silicone oils for polyester threads (PET threads) are mainly divided into three categories: base silicone oils, modified silicone oils and specialty silicone waxes. Different categories are suitable for different process stages and performance requirements. Below is the detailed classification and application guide:
I. Base Silicone Oil: Dimethyl Silicone Oil (Polydimethylsiloxane)
Core composition: Polysiloxane with all organic substituents being methyl groups, commonly known as "conventional silicone oil" or "201 silicone oil".
Performance characteristics: Excellent lubricity, heat resistance (above 200 °C), antistatic property, chemical stability and hydrophobicity.
Application scenarios:
- Basic lubrication treatment for general‑purpose polyester threads; called "thread‑passing silicone oil" or "thread‑making silicone oil" within the thread‑manufacturing industry.
- Usually compounded with white mineral oil; higher silicone‑oil content yields better quality.
- Medium‑to‑high viscosity (100‑1000 cSt) for high‑speed sewing threads; low viscosity (50‑100 cSt) for fine‑denier threads.
Limitations: Cannot self‑crosslink nor cross‑link with fibers; poor wash resistance.
II. Modified Silicone Oils: Options for Functional Upgrade
表格
| Type | Structural Features | Key Performances | Application Scenarios |
|---|---|---|---|
| Polyether‑modified silicone oil | Polyether‑grafted modified polydimethylsiloxane, water‑soluble | Lubricity + hydrophilicity + antistatic property, good fabric affinity | Polyester sewing threads (300‑500 cSt optimal); medical / sport‑apparel threads, anti‑wrinkle purposes |
| Amino‑modified silicone oil | Amino functional groups introduced onto siloxane backbone | Strong adsorption, good wash resistance, soft smoothness, forms robust protective films | High‑grade industrial sewing threads for long‑lasting‑effect applications |
| Epoxy‑functional silicone oil | Epoxy groups incorporated into molecular structure | Cross‑links with hydroxyl groups on fiber surfaces, excellent durability | Polyester threads requiring superior wash resistance and high‑temperature setting |
| Phenylmethyl silicone oil | Partial methyl groups replaced by phenyl groups | Higher thermal stability (>300 °C), good lubricity | Polyester thread treatment under extreme‑temperature conditions |
III. Specialty Silicone Waxes: Preferred Grade for High‑Speed Sewing Threads
Representative products: Dow Corning MEM‑1728 (DC1728), DC1727, domestically produced equivalent silicone waxes.
Structural features: Silicone resin / organic wax dispersions combining silicone‑oil lubricity and wax stability.
Performance advantages:
- Better thermal shielding effect than conventional silicone oils, low thread‑breakage rate (0.5 breaks / 4800 m/min), low fuzz generation.
- Low oil pickup rate (only 1/3 of conventional silicone oils), reduces oil‑bleeding problems.
- Superior lubricity and antistatic property; excellent performance on high‑speed winders and sewing machines.
Application scenarios: High‑speed industrial sewing threads (≥7000 rpm), embroidery threads, high‑tenacity threads.
IV. Silicone‑Oil Selection Guide for Polyester Threads
Selection by sewing speed:
- Low speed (≤4000 rpm): Ordinary dimethyl‑silicone‑oil emulsion is adequate.
- Medium speed (4000‑6000 rpm): Polyether‑modified silicone oil or amino‑modified silicone oil.
- High speed (≥7000 rpm): Specialty silicone wax (e.g. MEM‑1728); additional top‑coating with dimethyl silicone oil is required to enhance high‑temperature protection.
Selection by performance requirements:
- For lubricity + antistatic property: Polyether‑modified silicone oil.
- For long‑lasting softness + wash resistance: Amino‑modified silicone oil (low amine value).
- For high‑temperature stability + low oil bleeding: Silicone‑wax‑based products.
Viscosity reference standards:
- Polyester sewing threads: 300‑500 cSt optimal.
- High‑speed sewing threads: 100‑350 cSt dimethyl silicone oil or specialty silicone wax.
- Special requirements: High‑temperature‑resistant grades above 5000 cSt are available.
V. Typical Application Formulations
- General‑purpose polyester sewing threads: Dimethyl silicone oil (300‑500 cSt) compounded with white mineral oil, contact oil‑application method; oil content controlled at 2‑5 %.
- High‑speed industrial polyester threads: Treated with specialty silicone wax (e.g. MEM‑1728), oil pickup rate 0.8‑1.2 %, significantly lowering thread‑breakage rate.
- Functional polyester threads (medical / sport): Polyether‑modified silicone oil to endow threads with moisture‑absorbing, sweat‑wicking and antistatic functions.
Summary: Silicone oils for polyester threads are based on dimethyl silicone oil. Functional products such as polyether‑modified and amino‑modified silicone oils are selected according to specific demands. Silicone‑wax‑based specialty finishing agents are preferred for high‑speed sewing scenarios to obtain optimal lubricity, antistatic performance and high‑temperature resistance.
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