Flame-retardant nylon elastomer foam and preparation process thereof

Abstract

The invention provides flame-retardant nylon elastomer foam and a preparation process thereof. The flame-retardant nylon elastomer foam mainly comprises the following components in parts by mass: 100 parts of nylon elastomer, 8-20 parts of decabromodiphenyl ether, 4-10 parts of antimony trioxide, 0.3-0.5 part of an antioxidant and 1-2 parts of a chain extender ADR. The flame-retardant system is compounded from the systems, so that the foaming property of the nylon elastomer can be improved, and the flame-retardant property of the nylon elastomer foam can be effectively improved; meanwhile, integrated foaming forming is adopted, so that the process steps can be reduced, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of nylon elastomer foaming, in particular to a flame retardant nylon elastomer foam and a preparation process thereof. Background Art

[0002] Nylon thermoplastic elastomer is composed of polyamide hard segment and polyether soft segment. It has both the elasticity of rubber and the plasticity of plastic. It has excellent anti-fatigue, elasticity, low temperature resistance and other properties. It is widely used in cables, conveyor belts, sports and other fields. Nylon elastomer foam prepared by supercritical foaming method has excellent properties such as low specific gravity, high rebound, small compression deformation, etc. It is widely used in footwear and sports fields. However, since nylon elastomer itself is flammable, its foam products will cause serious fire hazards once they burn during use and storage, which greatly limits the application of nylon elastomer foam in fields with high flame retardancy requirements.

[0003] At present, the main methods for preparing nylon elastomer flame retardant materials include adding phosphorus flame retardants, metal hydroxides, intumescent flame retardants, silicone flame retardants, etc. At present, phosphorus flame retardants, nitrogen flame retardants and carbon-forming materials need to be added in large amounts to achieve a certain flame retardant effect, but they will cause great damage to the foaming properties of nylon elastomers. Halogen flame retardants can form hydrogen halides on the surface of polymers to capture active free radicals produced during the combustion process, cut off the chain reaction of combustion to retard flames. Compared with phosphorus nitrogen flame retardant systems, halogen flame retardants have better compatibility with polymers, and a small amount of addition can achieve a flame retardant effect. It has little effect on the foaming properties of polymers and is suitable for adding to low-density foaming materials.

[0004] Patent CN110183649A discloses a phosphorus-containing intrinsic flame-retardant thermoplastic nylon elastomer and a preparation method thereof, wherein the phosphorus-containing intrinsic flame-retardant thermoplastic nylon elastomer is obtained by melt copolymerization of carboxyl-terminated nylon prepolymer, hydroxyl-terminated polyether polyol and phosphorus-containing diol monomer, or by melt copolymerization of carboxyl-terminated phosphorus-containing nylon prepolymer and hydroxyl-terminated polyether polyol, and has a limiting oxygen index of 27% to 38%, and a vertical combustion UL-94 grade of V-0. Patent CN114591623A discloses a high impact toughness flame-retardant nylon elastomer material and a preparation method thereof, which adopts physical blending of phosphorus-containing flame-retardant nylon prepolymer and nylon elastomer matrix, and can effectively achieve synergistic enhancement of flame retardancy and impact toughness. The above two patents only involve the preparation of flame-retardant nylon elastomer, and only obtain nylon elastomer raw materials with flame retardant properties, and do not conduct foaming research on nylon elastomer materials.

[0005] Invention patent CN114316345A provides a low-shrinkage long-chain polyamide elastomer foaming bead and its preparation method and application. The invention is to mix the long-chain nylon elastomer and the processing aid evenly and then extrude and granulate them. The particles and water are placed in a high-pressure reactor for supercritical fluid foaming to obtain long-chain nylon elastomer foaming beads. In this scheme, the obtained nylon elastomer foaming beads cannot usually be used directly and need secondary steam molding, which increases the complexity of the process; and no flame retardant modification is performed, so its application field is limited.

[0006] In the foaming process of nylon elastomer, flame retardant fillers will have a great influence on the melt viscosity, crystallization performance and rheological properties of polymer materials, which will affect the foaming effect and make it impossible to obtain low-density and usable foam products. Therefore, it is necessary to develop a flame retardant supercritical nylon elastomer foam, which can greatly broaden the application range of nylon elastomer foam materials, so that it can be used in the automotive industry, building materials industry, shoes and clothing, packaging materials and other fields with high flame retardancy requirements. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a flame retardant nylon elastomer foam and a preparation process thereof, which enables the foam to obtain flame retardant properties without affecting the foaming properties of the nylon elastomer and improves the melt strength of the nylon elastomer.

[0008] To this end, a first object of the present invention is to provide a flame retardant nylon elastomer foam.

[0009] The second object of the present invention is to provide a process for preparing flame retardant nylon elastomer foam.

[0010] To achieve the first object of the present invention, a flame retardant nylon elastomer foam is provided, which mainly comprises the following components: 100 parts by mass of a nylon elastomer, (8 to 20) parts by mass of decabromodiphenyl ether, (4 to 10) parts by mass of antimony trioxide, (0.3 to 0.5) parts by mass of an antioxidant, and (1 to 2) parts by mass of a chain extender ADR.

[0011] In a preferred embodiment, the flame retardant nylon elastomer foam further comprises: (1-20) parts by mass of octabromodiphenyl ether and / or (0.1-5) parts by mass of aluminum hydroxide and / or (0.1-2) parts by mass of molybdenum trioxide.

[0012] In the above technical solution, nylon elastomer is selected as the foaming body. Compared with thermoplastic polyurethane foam and thermoplastic polyester foam, nylon elastomer foam material has lower density and higher resilience, and can be used in sports shoes and protection fields with high requirements on rebound and density.

[0013] Preferably, the hard segment raw material in the nylon elastomer is one or more crystalline nylons, such as nylon 12, nylon 11, nylon 6, nylon 612, nylon 610, and nylon 1012, and the soft segment raw material is one or more aliphatic polyesters, aliphatic polyethers, and aliphatic polycarbonates.

[0014] Preferably, the molecular weight of the soft segment aliphatic polyether is 500-3000.

[0015] Preferably, the Shore hardness of the nylon elastomer is 65A-70D.

[0016] Preferably, the melting point of the nylon elastomer is 120°C-180°C.

[0017] Preferably, the antioxidant is selected from one or more of antioxidants 1010, 168, 164, 1076, etc.

[0018] By selecting decabromodiphenyl ether and antimony trioxide as flame retardants, and combining them with antioxidants and chain extender ADR to prepare nylon elastomer foam, nylon elastomer foam with flame retardancy, low density and high resilience can be obtained.

[0019] Since the molecules of nylon elastomers are linear structures, their melt strength is poor at the required foaming temperature, and they are prone to deformation, cracks, bulging and other defects, which are not conducive to foaming. Therefore, it is necessary to extend the chain of nylon elastomer molecules to obtain good foaming performance. ADR has multiple epoxy functional groups, which can react with the amino and carboxyl groups on the nylon elastomer molecules to increase the molecular chain, improve the melt strength, and thus improve the foaming performance.

[0020] To achieve the second object of the present invention, a process for preparing a flame retardant nylon elastomer foam is provided, comprising the following steps:

[0021] Step S1, adding nylon elastomer, decabromodiphenyl ether, antimony trioxide and optional octabromodiphenyl ether, molybdenum trioxide and aluminum hydroxide into an internal mixer, adding antioxidant and chain extender ADR after mixing evenly, and obtaining a mixed sample after the reaction is completed;

[0022] Step S2, placing the mixed sample in a flat vulcanizer, heating and softening it, and compression molding it to obtain a sheet to be foamed;

[0023] Step S3, placing the sheet to be foamed into a supercritical foaming kettle, and foaming it in a carbon dioxide and nitrogen atmosphere to obtain a foamed sheet;

[0024] Step S4, placing the foamed board at room temperature to cool and set, thereby obtaining a flame-retardant nylon elastomer foam.

[0025] In step S1 of the present invention, the mixing temperature is 170° C. to 200° C., and the mixing time is 15 to 20 minutes.

[0026] In step S2 of the present invention, the compression molding conditions are: preheating and softening at 170°C to 200°C and 5-15MPA and then hot cold pressing.

[0027] In step S3 of the present invention, the volume ratio of carbon dioxide to nitrogen is 4:1-1:4, the supercritical foaming pressure is 10-30 MPa, the foaming temperature is 100-135°C, the foaming time is 1-3h, and the degassing temperature is 140-165°C.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] The invention selects decabromodiphenyl ether and antimony trioxide as flame retardants, adopts ADR to modify nylon elastomer, improves the melt strength of nylon elastomer, and obtains nylon elastomer foam with flame retardancy, low density and high resilience without affecting the foaming performance of nylon elastomer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a SEM image of the cell structure of the flame retardant nylon elastomer foam in Example 1;

[0031] Figure 2 a is a surface image of the flame retardant nylon elastomer foam after combustion in Example 5, and b is a surface image of the nylon elastomer foam after ablation in Comparative Example 1;

[0032] Figure 3 This is a SEM image of the cell structure of the nylon elastomer foam in Comparative Example 3;

[0033] Figure 4 The dispersion of the flame retardant in the nylon elastomer in Comparative Example 3;

[0034] Figure 5 In the figure, a is a picture of the flame retardant nylon elastomer foam of Example 4, and b is a picture of the flame retardant nylon elastomer foam of Comparative Example 4. DETAILED DESCRIPTION

[0035] In order to clearly understand the above-mentioned purposes, features and advantages of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0037] Ingredients Description:

[0038]

[0039]

[0040] Unless otherwise specified, other raw materials are commercially available.

[0041] Experimental equipment description:

[0042] Experimental equipment Manufacturer information Haake Torque Rheometer Shanghai Kechuang Rubber & Plastic Machinery Co., Ltd. Flat plate vulcanizing press XLB Qingdao Yadong Rubber Machinery Co., Ltd. Supercritical fluid foaming reactor self made Densitometer GT-XB320M High Speed ​​Rail Technology Co., Ltd. Oxygen Index Tester HC-2 Nanjing Jionglei Instrument Equipment Co., Ltd. Shore Hardness Tester (C) LX-C Yueqing Aidebao Instrument Co., Ltd. Universal stretching machine High Speed ​​Rail Technology Co., Ltd.

[0043] Test project description:

[0044] Test items Test methods and standards Apparent density GB / T6343-2009 Shore-C Hardness GB / T10807-2006 Rebound performance GB / T6670-2008 Tensile Strength GB / T 6344-2008 Vertical rebound of falling ball GB / T 6670-2008 Limiting oxygen index GB / T 2406.2-2009

[0045] Example 1

[0046] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0047] The flame retardant nylon elastomer foam formula is: 100 parts of nylon elastomer A, 8 parts of decabromodiphenyl ether, 4 parts of antimony trioxide, 2 parts of aluminum hydroxide, 0.3 parts of antioxidant 1010, and 1.5 parts of chain extender ADR4468. After the nylon elastomer is completely dried, it is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60r / min. After mixing for 5 minutes until the torque is stable, the chain extender is added according to the proportion and the mixing is continued for more than 5 minutes until the torque is stable. After that, decabromodiphenyl ether, antimony trioxide, aluminum hydroxide, and antioxidant 1010 are added to the Haake torque rheometer and mixed for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0048] Step 2: Molding of flame retardant nylon elastomer composite material:

[0049] The blended material was placed in a mold, and hot-pressed for 5 minutes at a temperature of 180° C. and a pressure of 10 MPa, and then cold-pressed for 5 minutes to obtain a sheet to be foamed.

[0050] Step 3: Flame retardant nylon elastomer foaming:

[0051] The board to be foamed was placed in a supercritical foaming reactor at 110°C, and carbon dioxide and nitrogen (volume ratio of 1:1) were introduced until saturation at 10MPa for 4 hours, and then the temperature was raised to 140°C and the gas was quickly released to obtain a flame-retardant nylon elastomer foam material.

[0052] Step 4: Cooling and shaping the foamed material at room temperature to obtain a flame retardant nylon elastomer foam material.

[0053] Example 2

[0054] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0055] The flame retardant nylon elastomer foam formula is: 100 parts of nylon elastomer A, 10 parts of decabromodiphenyl ether, 4 parts of antimony trioxide, 3 parts of aluminum hydroxide, 0.3 parts of antioxidant 168, and 1.5 parts of chain extender ADR4468. The nylon elastomer is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60r / min. After mixing for 5 minutes until the torque is stable, the chain extender is added in proportion and the mixing is continued for more than 5 minutes until the torque is stable. After that, decabromodiphenyl ether, antimony trioxide, aluminum hydroxide, and antioxidant 1010 are added to the Haake torque rheometer for mixing for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0056] Step 2: Molding of flame retardant nylon elastomer composite material:

[0057] The blended material was placed in a mold, and hot-pressed for 5 minutes at a temperature of 190° C. and a pressure of 8 MPa, and then cold-pressed for 5 minutes to obtain a sheet to be foamed.

[0058] Step 3: Flame retardant nylon elastomer foaming:

[0059] The board to be foamed was placed in a supercritical foaming reactor at 110°C, and carbon dioxide and nitrogen (the volume ratio of the two was 1:1) were introduced until saturation at 10MPa for 4 hours, and then the temperature was raised to 155°C and the gas was quickly released to obtain a flame-retardant nylon elastomer foam material.

[0060] Step 4: Cooling and shaping the foamed material at room temperature to obtain a flame retardant nylon elastomer foam material.

[0061] Example 3

[0062] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0063] The flame retardant nylon elastomer foam formula is: 100 parts of nylon elastomer B, 12 parts of decabromodiphenyl ether, 6 parts of antimony trioxide, 2 parts of aluminum hydroxide, 0.3 parts of antioxidant 1010, and 1.5 parts of chain extender ADR4468. The nylon elastomer is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60r / min. After mixing for 5 minutes until the torque is stable, the chain extender is added according to the proportion and the mixing is continued for more than 5 minutes until the torque is stable. The other raw materials are added to the Haake torque rheometer and mixed for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0064] The molding, foaming and cooling process are the same as those in Example (1) to obtain a flame retardant nylon elastomer foam material.

[0065] Example 4

[0066] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0067] The flame retardant nylon elastomer foam formula is: 100 parts of nylon elastomer A, 16 parts of decabromodiphenyl ether, 6 parts of antimony trioxide, 1 part of molybdenum trioxide, 0.3 parts of antioxidant 1010, and 1.5 parts of chain extender ADR4468. The nylon elastomer is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60r / min. After mixing for 5 minutes until the torque is stable, the chain extender is added according to the proportion and the mixing is continued for more than 5 minutes until the torque is stable. The other raw materials are added to the Haake torque rheometer and mixed for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0068] The molding, foaming and cooling process are the same as those in Example (1) to obtain a flame retardant nylon elastomer foam material.

[0069] Example 5

[0070] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0071] The flame retardant nylon elastomer foam formula is: 100 parts of nylon elastomer A, 20 parts of decabromodiphenyl ether, 6 parts of antimony trioxide, 1 part of molybdenum trioxide, 0.3 parts of antioxidant 168, and 1.5 parts of chain extender ADR4468. The nylon elastomer is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60r / min. After mixing for 5 minutes until the torque is stable, the chain extender is added according to the proportion and the mixing is continued for more than 5 minutes until the torque is stable. The other raw materials are added to the Haake torque rheometer and mixed for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0072] The molding, foaming and cooling process are the same as those in Example (1) to obtain a flame retardant nylon elastomer foam material.

[0073] Example 6

[0074] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0075] The flame retardant nylon elastomer foam formula is: 100 parts of nylon elastomer B, 20 parts of decabromodiphenyl ether, 5 parts of octabromodiphenyl ether, 10 parts of antimony trioxide, 1 part of molybdenum trioxide, 0.3 parts of antioxidant 1010, and 1.5 parts of chain extender ADR4468. The nylon elastomer is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60r / min. After mixing for 5 minutes until the torque is stable, the chain extender is added according to the proportion and the mixing is continued for more than 5 minutes until the torque is stable. The other raw materials are added to the Haake torque rheometer and mixed for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0076] The molding, foaming and cooling process are the same as those in Example (1) to obtain a flame retardant nylon elastomer foam material.

[0077] Example 7

[0078] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0079] The flame retardant nylon elastomer composite material formula is: 100 parts of nylon elastomer B, 8 parts of decabromodiphenyl ether, 15 parts of octabromodiphenyl ether, 8 parts of antimony trioxide, 1 part of molybdenum trioxide, 0.3 parts of antioxidant 1010, and 1.5 parts of chain extender ADR4468. The nylon elastomer is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60r / min. After mixing for 5 minutes until the torque is stable, the chain extender is added in proportion and the mixing is continued for more than 5 minutes until the torque is stable. The flame retardant and antioxidant are added to the Haake torque rheometer and mixed for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0080] The molding, foaming and cooling process are the same as those in Example (1) to obtain a flame retardant nylon elastomer foam material.

[0081] Comparative Example 1

[0082] Step 1, add 100 parts by mass of nylon elastomer into the Haake torque rheometer and mix, set the mixing temperature to 190°C, the rotation speed to 60r / min, mix for 5 minutes until the torque is stable, add 16 parts of decabromodiphenyl ether, 0.3 parts of antioxidant 1010, 1.5 parts of chain extender ADR4468, and 1 part of molybdenum trioxide into the Haake torque rheometer and mix for more than 5 minutes until the torque is stable, then take out to obtain a flame retardant nylon elastic blend.

[0083] The molding, foaming and testing process are the same as in Example (4) to obtain a nylon elastomer foam material.

[0084] Comparative Example 2

[0085] Step 1: Mixing of flame retardant nylon elastomer composite material:

[0086] The flame retardant nylon elastomer composite material formula is: 100 parts of nylon elastomer A, 16 parts of decabromodiphenyl ether, 6 parts of antimony trioxide, 1 part of molybdenum trioxide, and 0.3 parts of antioxidant 1010. After the nylon elastomer is completely dried, it is added to the Haake torque rheometer for mixing, and the mixing temperature is set to 190°C and the speed is 60rad / min. After mixing for 5 minutes until the torque is stable, the other raw materials are added to the Haake torque rheometer and mixed for more than 5 minutes until the torque is stable, and then taken out to obtain a flame retardant nylon elastomer blend.

[0087] The molding, foaming and testing process are the same as in Example (4) to obtain a nylon elastomer foam material.

[0088] Comparative Example 3

[0089] Step 1, the flame retardant nylon elastomer composite material formula is: 100 parts of nylon elastomer A, 30 parts of diethyl aluminum hypophosphite, 5 parts of melamine cyanurate, 0.3 parts of antioxidant 1010, and 1.5 parts of chain extender ADR4468. Add the nylon elastomer to the Haake torque rheometer for mixing, set the mixing temperature to 190°C, the speed to 60r / min, mix for 5 minutes until the torque is stable, add the chain extender according to the proportion, and continue to mix for more than 5 minutes until the torque is stable, add the flame retardant and antioxidant to the Haake torque rheometer, mix for more than 5 minutes until the torque is stable, and then take out to obtain a flame retardant nylon elastomer blend.

[0090] The molding, foaming and cooling process are the same as those in Example (1) to obtain a flame retardant nylon elastomer foam material.

[0091] The experimental results show that the addition of phosphorus-nitrogen flame retardants has a significant impact on the foaming properties of nylon elastomers, and it is impossible to obtain a complete foamed sheet. In addition, a high addition amount causes a loss of the resilience of the nylon elastomer foam. From the perspective of flame retardancy, the limiting oxygen index of the foamed material is only 24.5 after adding nitrogen-phosphorus flame retardants, which cannot meet the flame retardancy requirements. Figure 3 The dispersion of flame retardant in the cell wall is shown in Figure 4 .

[0092] Comparative Example 4

[0093] Step 1, the flame retardant nylon elastomer composite material formula is: nylon elastomer A100 parts, antioxidant 1010 0.3 parts, chain extender ADR4468 1.5 parts, red phosphorus 10 parts, diethyl aluminum hypophosphite 10 parts, wood fiber 5 parts, dipentaerythritol 5 parts, expanded graphite 4 parts. Add the nylon elastomer to the Haake torque rheometer for mixing, set the mixing temperature to 190 ° C, the speed to 60r / min, mix for 5 minutes until the torque is stable, add the chain extender according to the proportion, and continue to mix for more than 5 minutes until the torque is stable, add other substances to the Haake torque rheometer, mix for more than 5 minutes until the torque is stable, and then take out to obtain a flame retardant nylon elastomer blend.

[0094] The molding, foaming and cooling process are the same as those in Example (1) to obtain a flame retardant nylon elastomer foam material.

[0095] Comparative Example 5

[0096] Step 1, 100 parts of nylon elastomer A, 20 parts of decabromodiphenylethane, 6 parts of antimony trioxide, 1 part of molybdenum trioxide, 0.3 parts of antioxidant 168, and 1.5 parts of chain extender ADR4468. Add the nylon elastomer to the Haake torque rheometer and mix, set the mixing temperature to 190°C and the speed to 60r / min, mix for 5 minutes until the torque is stable, add the chain extender in proportion, and continue to mix for more than 5 minutes until the torque is stable, add the other raw materials to the Haake torque rheometer and mix for more than 5 minutes until the torque is stable, and then take out to obtain a flame retardant nylon elastomer blend.

[0097] The molding, foaming and testing process are the same as in Example (5) to obtain a nylon elastomer foam material.

[0098] Table 1 Flame retardant nylon elastomer foam performance test table

[0099] <![CDATA[Density g / cm 3 > Hardness C Vertical rebound% Tensile strength MPa Limiting oxygen index % Flame retardant grade Example 1 0.121 50 69 1.94 27 HF-1 Example 2 0.105 47 71 1.62 26.7 HF-1 Example 3 0.119 50 68 1.77 28 HF-1 Example 4 0.12 48 67 1.76 28 HF-1 Example 5 0.121 50 67 1.8 29 HF-1 Example 6 0.12 49 68 1.7 29.5 HF-1 Example 7 0.117 47 68 1.68 28 HF-1 Comparative Example 1 0.126 50 62 2.04 23 --- Comparative Example 2 0.13 46 61 1.1 27 HF-1 Comparative Example 3 0.137 49 52 0.81 24.5 HF-2 Comparative Example 4 0.21 60 57 0.86 28.5 HF-1 Comparative Example 5 0.194 55 54 0.94 26.2 HF-1

[0100] The density of the flame retardant nylon elastomers in Examples 1-7 is generally lower than that in the comparative example, indicating that the chain extender ADR4468 can effectively improve the foaming properties of the nylon elastomer.

[0101] The vertical rebound of the falling ball of Examples 1-7 is generally higher than that of Comparative Examples 3 and 4, indicating that the use of a compound of decabromodiphenyl ether and antimony trioxide as a flame retardant has less effect on the hardness, rebound, stretch and other properties of nylon elastomer foam than phosphorus-based and nitrogen-based flame retardants.

[0102] In Comparative Example 1, only decabromodiphenyl ether was used as a flame retardant, and the obtained nylon elastomer foam had poor flame retardancy; in Comparative Example 2, no chain extender was added, and a nylon elastomer foam with good flame retardancy but poor foaming effect was obtained. Comparative Examples 3 and 4 respectively used the nitrogen-phosphorus compound flame retardant system and the intumescent flame retardant system in the prior art, and although a high flame retardant effect could be achieved, the performance loss of the nylon elastomer foam was large. Comparative Example 5 used decabromodiphenyl ethane as the main flame retardant, which had a great influence on the foaming performance of the nylon elastomer, and defects appeared inside the foam, and the performance decreased; and it did not significantly improve the flame retardant performance of the nylon elastomer foam.

[0103] from Figure 1 It can be seen that the pore structure of the nylon elastomer is complete and the pore size is uniform.

[0104] from Figure 2 From the picture of Example 5 after ablation in a, it can be seen that there is a carbon layer on the surface without dripping, and from b, it can be seen that there is dripping during the ablation process and no flame-retardant carbon layer can be formed.

[0105] from Figure 3 It can be seen that after adding nitrogen-phosphorus flame retardants, the pores of nylon elastomer foam have more damage and cracks, the structure is no longer complete, and the size is poor; Figure 4 It can be seen that the nitrogen-phosphorus flame retardant is large in size and poorly dispersed in the nylon elastomer, causing more defects inside the nylon elastomer foam.

[0106] from Figure 5 It can be seen that Example 4 ( Figure 5 a) has no defects inside the foam, while Comparative Example 4 ( Figure 5 b) and Comparative Example 5 ( Figure 5 The foam of c) has multiple stratifications, and the stratifications are formed by the breakage of the cells during the foaming process.

[0107] It can be seen from the comparison between Comparative Example 5 and Example 5 that although other bromine-based flame retardants can play a flame retardant effect in this system, they will affect the foaming performance of the nylon elastomer, and the vertical rebound and tensile strength of the prepared nylon elastomer foam material are poor.

[0108] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A flame retardant nylon elastomer foam, characterized in that: The invention comprises the following components: 100 parts by weight of nylon elastomer, 8-20 parts by weight of decabromodiphenyl ether, 4-10 parts by weight of antimony trioxide, 0.3-0.5 parts by weight of antioxidant and 1-2 parts by weight of chain extender ADR.

2. The flame retardant nylon elastomer foam according to claim 1, characterized in that: The foam further comprises 1 to 20 parts by mass of octabromodiphenyl ether and / or 0.1 to 5 parts by mass of aluminum hydroxide and / or 0.1 to 2 parts by mass of molybdenum trioxide.

3. The flame retardant nylon elastomer foam according to claim 1 or 2, characterized in that: The hard segment raw material in the nylon elastomer is selected from one or more crystalline nylons, preferably nylon 12, nylon 11, nylon 6, nylon 612, nylon 610, and nylon 1012, and the soft segment raw material is one or more of aliphatic polyesters, aliphatic polyethers, and aliphatic polycarbonates.

4. The flame retardant nylon elastomer foam according to claim 1 or 2, characterized in that: The antioxidant is one or more of antioxidant 1010 , antioxidant 168 , antioxidant 164 , and antioxidant 1076 .

5. A process for preparing a flame retardant polynylon elastomer foam, characterized in that: The following steps are involved: Step S1, mixing nylon elastomer, decabromodiphenyl ether, antimony trioxide, and optional aluminum hydroxide, octabromodiphenyl ether, and molybdenum trioxide, adding an antioxidant and a chain extender ADR after mixing evenly, and obtaining a mixed sample after the reaction is completed; Step S2, heating and softening the mixed sample and performing compression molding to obtain a sheet to be foamed; Step S3, placing the sheet to be foamed into a supercritical foaming kettle, and foaming it in a carbon dioxide and nitrogen atmosphere to obtain a foamed sheet; Step S4, cooling and shaping the foamed board to obtain a flame-retardant nylon elastomer foam.

6. The preparation process according to claim 5, characterized in that: In step S1, the mixing temperature is 170-200° C., and the mixing time is 15-20 min.

7. The preparation process according to claim 5, characterized in that: In step S2, the hot cold pressing is performed after preheating and softening at 170-200°C and 5-15MPa.

8. The preparation process according to claim 5, characterized in that: In step S3, the foaming pressure is 10-30 MPa, the foaming temperature is 100-135°C, the foaming time is 1-3 hours, and the degassing temperature is 140-165°C.

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