PA66 聚酰胺66或尼龍66

典型應用范圍:
同PA6相比，PA66更廣泛應用于汽車工業、儀器殼體以及其它需要有抗沖擊性和高強度要求的產品。

注塑模工藝條件:
干燥處理：如果加工前材料是密封的，那么就沒有必要干燥。然而，如果儲存容器被打開，那么建議在85C的熱空氣中干燥處理。如果濕度大于0.2%，還需要進行105C，12小時的真空干燥。
熔化溫度：260~290C。對玻璃添加劑的產品為275~280C。熔化溫度應避免高于300C。
模具溫度：建議80C。模具溫度將影響結晶度，而結晶度將影響產品的物理特性。對于
薄壁塑件，如果使用低于40C的模具溫度，則塑件的結晶度將隨著時間而變化，為了保持
塑件的幾何穩定性，需要進行退火處理。
注射壓力：通常在750~1250bar，取決于材料和產品設計。
注射速度：高速（對于增強型材料應稍低一些）。
流道和澆口:
由于PA66的凝固時間很短，因此澆口的位置非常重要。澆口孔徑不要小于0.5*t
（這里t為塑件厚度）。如果使用熱流道，澆口尺寸應比使用常規流道小一些，
因為熱流道能夠幫助阻止材料過早凝固。如果用潛入式澆口，澆口的最小直徑
應當是0.75mm。

化學和物理特性:
PA66在聚酰胺材料中有較高的熔點。它是一種半晶體-晶體材料。PA66在較高溫度也能保持較強的強度和剛度。PA66在成型后仍然具有吸濕性，其程度主要取決于材料的組成、壁厚以及環境條件。在產品設計時，一定要考慮吸濕性對幾何穩定性的影響。
為了提高PA66的機械特性，經常加入各種各樣的改性劑。玻璃就是最常見的添加劑，有時為了提高抗沖擊性還加入合成橡膠，如EPDM和SBR等。
PA66的粘性較低，因此流動性很好（但不如PA6）。這個性質可以用來加工很薄的元件。
它的粘度對溫度變化很敏感。PA66的收縮率在1%~2%之間，加入玻璃纖維添加劑可以將
收縮率降低到0.2%~1% 。收縮率在流程方向和與流程方向相垂直方向上的相異是較大的。
PA66對許多溶劑具有抗溶性，但對酸和其它一些氯化劑的抵抗力較弱。

PA 66

Generic Class

PA 66 (Polyamide 66, or Nylon 66, or poly (hexamethylene adipamide))

Applications

Competes with PA 6 for most applications. PA 66 is heavily used in the automotive industry, appliance housings, and generally where impact resistance and strength are required.

Injection Molding Processing conditions

Drying	Drying is not required if the material is sealed prior to molding; however, if the containers are left open, drying in a hot air oven at 85 C (185 F) is recommended. If the moisture content is > 0.2%, vacuum drying at 105 C (220 F) for 12 hours is recommended.
Melt Temperature	260 - 290 C (500 - 554 F); 275 - 280 C (527 - 536 F) for glass filled grades; melt temperatures above 300 C (572 F) should be avoided
Mold Temperature	80 C (176 F) suggested. Mold temperature affects crystallinity level which in turn affects physical properties. In the case of thin walled parts, crystallinity changes with time if mold temperatures of less than 40 C (104 F) are used. In such cases, annealing may be needed to retain dimensional stability.
Resin Injection Pressure	Generally between 750 - 1,250 bar (~11,000 - 18,000 psi), depends on material and product design
Injection Speed	High (slightly lower for reinforced grades)

Runners and Gates

The gate location is important because of very fast freeze-off times. Any type of gate may be used; the aperture should not be less than half the thickness of the part. When hot runners are used, the size of the gates can be smaller than when cold runners are used, because premature freeze-off is prevented. When using submarine gates, the minimum diameter of the gate should be 0.75 mm.

Chemical and physical properties

PA 66 homopolymer is produced by the polymerization of hexamethylene diamine and adipic acid (a dibasic acid). Among commercially available polyamides, PA 66 has one of the highest melting points. It is a semicrystalline-crystalline material. The resins have strength and stiffness which is retained at elevated temperatures. It does absorb moisture after molding, but the retention is not as much as in the case of PA 6. Moisture absorption depends on the composition of the material, wall thickness, and environmental conditions. Dimensional stability and properties are all affected by the amount of moisture absorption which must be taken into account for product design.

Various modifiers are added to improve mechanical properties; glass is one of the most commonly used filler. Addition of elastomers such as EPDM or SBR improves impact resistance.

The viscosity is low and therefore, it flows easily (but not as easily as PA 6). This allows molding of thin components. The viscosity is very sensitive to temperature. Shrinkage is of the order of 0.01 - 0.02 mm/mm (1 - 2%). Addition of reinforcing glass fibers reduces the shrinkage to 0.2 - 1%. Differential shrinkage in the flow and cross-flow directions is quite high. Mineral fillers yield more isotropic moldings. PA 66 is resistant to most solvents but not to strong acids or oxidizing agents.

Major Manufacturers

BASF (Ultramid A), DuPont (Minlon - mineral reinforced grades; Zytel), Monsanto (Vydyne), DSM (Akulon).