Abstract: This paper introduces the characteristics, composition, application range and application examples of the non-halogen flame retardant for glass fiber reinforced nylon and polyester in UK. EPFR series glass fiber reinforced special halogen-free flame retardants are divided into two categories, the first category is applied to glass fiber nylon; the second type is applied to glass fiber polyester. The above EPFR series of phosphorus-nitrogen expansion type environmentally friendly flame retardants have the advantages of no red phosphorus, low smoke, low toxicity, high efficiency, good compatibility and little influence on the performance of the substrate.
Keywords: glass fiber nylon glass fiber polyester halogen-free flame retardant new development: out of respect for life, more and more responsible manufacturers began to use halogen-free flame retardant materials. These responsible manufacturers need to achieve UL94-V0 flame retardant, meet the requirements of glow wire, and have a variety of properties, such as halogen-free flame retardant glass fiber reinforced nylon and halogen-free flame retardant glass fiber reinforced polyester.
Current flame retardants are used in glass fiber reinforced nylon and polyester problems:
1 . One of the most important halogen-containing flame retardant systems is the brominated styrene polymer, which has extremely excellent thermal stability and, because it is melt-mixable with nylon, it is processed during processing. It has good fluidity. In addition, the flame retardant nylon prepared by the same has superior electrical properties and good physical and mechanical properties. The limitation of this flame retardant is that the light stability is poor, and it is not completely compatible with nylon, and its cost is also higher than that of the widely used decabromodiphenyl ether in China.
At present, the most widely used flame retardant in China is decabromodiphenyl ether. Because of its high bromine content, it has high flame retardant efficiency for nylon, and it is the most economical flame retardant. However, since it is a filler type flame retardant, it has a great negative impact on the processing fluidity and the physical and mechanical properties of the product. Especially in today's increasingly complex product structures such as electrical connectors, the processing fluidity requirements for resins are also increasing. Poorly fluid resins simply cannot meet the requirements of processing small and complex parts. Therefore, it is conceivable that such filled flame retardants are difficult to apply in high-grade fields, and in addition, their thermal stability and light stability are also poor.
A new flame retardant developed in the past few years for the flame retardant of nylon and polyester is decabromodiphenylethane, which has the same bromine content and the same high flame retardant efficiency as decabromodiphenyl ether. In addition, it also has good thermal stability and light stability. The limitation is that it is the same filler type flame retardant as the decabromodiphenyl ether, and has poor compatibility with the polymer, so the processing fluidity and the physical and mechanical properties of the product are poor.
2 . Halogen-free flame retardant system Red phosphorus is one of the widely used halogen-free flame retardants in nylon and polyester, and has the advantages of less added amount and wide application. Ordinary red phosphorus is easy to absorb moisture, and has poor compatibility with polymer materials, and is particularly prone to spontaneous combustion and cannot be used practically. The microencapsulated red phosphorus flame retardant reduces the activity of red phosphorus and solves the compatibility. The red phosphorus content is about 85%, but the spontaneous combustion problem has not been effectively solved, and the dust pollution is serious. The red phosphorus masterbatch is a dark red particle in which a red phosphorus is mixed with an inorganic flame retardant such as aluminum hydroxide or expanded graphite, and a matrix resin is used as a carrier, and the safety problem is solved. The flame retardant system has low smoke and high flame retardant efficiency; no dust pollution, excellent processing performance; low density, good thermal stability, less physical property degradation; no frost, no migration, no corrosion of the mold during processing. In particular, the product has a high tracking index (CTI), which has obvious advantages in electronic and electrical applications. The main disadvantage of red phosphorus masterbatch is the hue problem, which, in addition to dark red and black, does not give the article more color choices.
Ammonium polyphosphate (APP) has the characteristics of high phosphorus content and low addition, and is also used for the preparation of flame retardant nylon and polyester, but the main disadvantage of APP is that it has strong hygroscopicity and low thermal stability (at 230 ° C). When the process of removing NH ₃ occurs, it is easily decomposed during the processing of nylon and polyester, resulting in foaming and discoloration of the product.
Polymelamine phosphate (MPP) is another environmentally friendly flame retardant widely used in the flame retardant of nylon and polyester. Its molecular chain structure is similar to that of APP. It mainly replaces NH ₄ ^{+ in the} side group with melamine with relatively large molecular weight ^. Therefore, its thermal stability is improved, but the phosphorus content of MPP is low. It has been found through experiments that 25% of MPP can only increase the oxygen index of glass fiber reinforced PA66 by 5.5%, while the vertical burning performance is hardly improved. Therefore, it is necessary to add more MPP to the flame retardant PA66, resulting in mechanical properties of the resin. Severe decline. Melamine cyanurate (MCA) is also commonly used in nylon and polyester flame retardant. It is characterized by low toxicity, no corrosion, and is stable to heat and ultraviolet rays. However, with its flame retardant nylon and polyester, it is very powerful when burned. The flame retardancy of glass fiber reinforced nylon and polyester is poor, and it can not reach UL94-V0 grade. The electrical properties of the product in the humid environment are not good, and the dispersibility in the substrate is not good, and the processing is difficult.
Inorganic flame retardants (such as magnesium hydroxide) have the advantages of low toxicity, low corrosion and low smoke. However, when used in nylon and polyester, it is easy to dehydrate water during processing, so it is not suitable.
Phosphate flame retardants (such as Exolit 1312 and Exolit 1240) are relatively superior for glass fiber reinforced flame retardant nylon and polyester, but their price is 3-5 times that of ordinary flame retardants. Fiber reinforced flame retardant nylon and polyester are very expensive and are not currently widely used in conventional glass reinforced flame retardant nylon and polyester products.
Characteristics and applications of phosphorus-nitrogen environmentally friendly glass fiber reinforced halogen-free flame retardant in EPFR series:
UK Presafer has recently launched the EPFR series of nitrogen and phosphorus environmentally friendly glass fiber reinforced halogen-free flame retardants, which are divided into two categories according to different application areas.
1 . EPFR-200A is mainly used in glass fiber reinforced PA66.
1EPFR-200A has high thermal stability. Its initial decomposition temperature is above 320 °C, which can meet the demanding conditions of nylon processing and injection molding, without the phenomenon of foaming during extrusion, degradation of flame retardant, discoloration of extruded particles.
2EPFR-200A is specially surface treated. It is easy to disperse in nylon and is compatible with nylon, so that reinforced nylon can maintain excellent mechanical properties while maintaining flame retardant properties.
3EPFR-200A has good electrical properties and can meet the application of reinforced nylon in the fields of electronics and electrical appliances.
4EPFR-200A has good flame retardant properties and can meet the requirements of different test standards such as UL94-V0 and glow wire.

Figure 1 UL94-V0 vertical burning test

Figure 2 IEC 60695 glow wire test

2 . EPFR-300A is mainly used in glass fiber reinforced PBT.
1EPFR-300A has high thermal stability. Its initial decomposition temperature reaches above 280 °C, which can meet the demanding polyester processing and injection molding conditions, without the phenomenon of foaming during extrusion, degradation of flame retardant, discoloration of extruded particles.
2EPFR-300A is specially surface treated. It is easy to disperse in polyester and is compatible with polyester, so that the reinforced polyester can maintain excellent mechanical properties while maintaining flame retardant properties.
3EPFR-300A has good electrical properties. CTI reaches 600V, which can meet the application of glass fiber reinforced polyester in electronic appliances and other fields.
4EPFR-300A has good flame retardant properties, and the corresponding number of flame retardants can meet the requirements of different test standards such as UL94-V0 (0.75mm and 1.5mm) and glow wire.
Application examples:

Table 1 (PA66)	standard test	unit	10% glass fiber	20% glass fiber	25% glass fiber	30% glass fiber
density	ASTM D-792	g/cm 3	1.35	1.32	1.39	1.45
Heat distortion temperature (0.45Mpa)	ASTM D-648	°C	255	255	255	257
Heat distortion temperature (1.82Mpa) (1.82Mpa)	ASTM D-648	°C	---	240	245	250
Tensile yield strength	ASTM D-638	Mpa	90	115	130	148
Elongation at break	ASTM D-638	%	7	5	5	3
Bending strength	ASTM D-790	Mpa	135	170	200	240
Flexural modulus	ASTM D-790	Mpa	5000	7000	8500	10500
Notched impact strength (23 ° C)	ASTM D-256	J/m	40	60	80	115
Flame retardancy	UL94	1.5mm 3.0mm	V0	V0	V0	V0
		3.0mm	V0	V0	V0	V0
Trace Leakage Resistance Index (CTI)	IEC60112	V	550	550	550	550

10% glass fiber according to PA66: EPFR-200A: GF=60:30:10
20% glass fiber according to PA66: EPFR-200A: GF=56:24:20
25% glass fiber according to PA66: EPFR-200A: GF=51:24:25
30% glass fiber according to PA66: EPFR-200A: GF=47:23:30

Table 2 (PBT)	standard test	unit	15% glass fiber	20% glass fiber	30% glass fiber	35% glass fiber
density	ASTM D-792	g/cm 3	1.48	1.52	1.55	1.62
Heat distortion temperature (0.45Mpa)	ASTM D-648	°C	217	221	221	221
Heat distortion temperature (1.82Mpa) (1.82Mpa)	ASTM D-648	°C	207	210	210	210
Tensile yield strength	ASTM D-638	Mpa	70	90	110	115
Elongation at break	ASTM D-638	%	10	8	3	3
Bending strength	ASTM D-790	Mpa	110	130	150	155
Flexural modulus	ASTM D-790	Mpa	4500	6000	8200	9150
Notched impact strength (23 ° C)	ASTM D-256	J/m	60	75	90	95
Flame retardancy	UL94	0.75mm 3.0mm	V-0	V-0	V-0	V-0
		1.5mm	V-0	V-0	V-0	V-0
Trace Leakage Resistance Index (CTI)	IEC60112	V	600	600	600	600

10% glass fiber according to PBT: EPFR-300A: GF=65:20:15
20% glass fiber according to PBT: EPFR-300A: GF=60:20:20
30% glass fiber according to PBT: EPFR-300A: GF=53:17:30
35% glass fiber according to PBT: EPFR-300A: GF=48:17:35
Issues to be aware of during processing and molding:
1 . The raw materials need to be pre-dried before processing. It can be used until it has a moisture content of 0.1% or less.
2. Choose the mildest processing conditions possible. Under the premise of ensuring that the raw materials and the powder are uniformly mixed and the glass fiber is smoothly added, the processing is performed under the conditions of lower temperature and weaker shearing. Among them, the processing temperature of EPFR-300A in PBT is as close as possible to 220 °C.
3. The choice of toughening agent is very critical. Excellent toughening agents not only improve the toughness of the material, but also improve the compatibility of the powder with the material, and greatly improve the other properties of the material.
4. The choice of glass fiber is very important. Since the number of glass fiber added in the material is very large, the compatibility of the glass fiber and the material determines the properties of the material. Therefore, the short fiber of the surface treatment of the coupling agent is preferred, and of course, the long fiber can also be used.
5. Selection of other additives. Adding appropriate nucleating agents will help the crystallization rate and morphology of the material and improve the properties of the material. Adding appropriate antioxidants will help prevent yellowing of the materials during processing; adding appropriate functional additives, Helps to adjust and improve the performance of materials.
6. Injection molding process conditions. Under the premise of molding, try to use the mild temperature and the appropriate pressure for injection molding. In addition, EPFR-300A needs to be carefully formulated with other flame retardants.
Conclusion: Compared with various flame retardants currently used in the market, EPFR-200A applied to glass fiber reinforced PA66 and EPFR-300A applied to glass fiber reinforced PBT has the following advantages: 1 high efficiency flame retardant performance; 2 good processing performance 3 excellent color stability; 4 excellent mechanical properties; 5 high thermal stability; 6 reasonable price.

1.The seal is replacable for BT AR type.
2.We have all the mould from 8mm to 70mm, all the rubber mould have LM (our trade mark)printed. 
3.From shaft size 30mm, we will use metal cup to hold the rubber to avoid its disassemblying after long time.
4.The color of ceramic could be yellow and white for clients choice. 

    We are adhering to the principle of "quality first" from the procurement of raw materials to the manufacturing process. We have aspecial quality inspector to ensure  every product is qualified before  ex-factory.

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