CN116656125A - A kind of nylon material and preparation method thereof - Google Patents

Abstract

The application relates to a nylon material and a preparation method thereof, wherein the nylon material comprises polyamide resin, halogen-free flame retardant, glass fiber, heat stabilizer, lubricant, free radical quencher and acid absorber. According to the application, by selecting a proper free radical quencher and matching with an acid absorber, the catalytic degradation of the flame retardant and the micromolecule substance separated out from the halogen-free flame retardant nylon material on the rubber material contacted with the flame retardant and the micromolecule substance is inhibited, so that the rubber sealing ring still has good elasticity and sealing performance after long-term use and wet heat aging.

Description

A kind of nylon material and preparation method thereof

technical field

The invention belongs to the field of modified plastics, in particular to a nylon material and a preparation method thereof.

Background technique

Rubber-based sealing materials have the advantages of good elasticity, good corrosion resistance, simple manufacturing process, and low cost, and are currently the most widely used sealing materials. After the rubber is compressed, it produces elastic deformation, shrinkage elastic deformation and plastic deformation that strive to return to its original shape. Elastic deformation and shrinkage Elastic deformation is the mechanism for rubber to achieve sealing effect. Under the long-term action of stress or the aging or even embrittlement of rubber itself, elastic deformation will transform into plastic deformation, causing seal failure. The types of rubber used to prepare sealing rings include silicone rubber, fluorine rubber, polyacrylate rubber, butyl rubber, ethylene propylene rubber, styrene-butadiene rubber, and the like.

Flame-retardant nylon materials achieve a specific level of flame-retardant performance by introducing flame retardants. According to the types of flame retardants, common flame-retardant nylon materials on the market can be divided into two categories: brominated flame-retardant and halogen-free flame-retardant. Among them, Halogen-free flame retardant can be subdivided into phosphorus flame retardant, nitrogen flame retardant, intumescent flame retardant and other types. On the one hand, brominated flame-retardant nylon materials are required by environmental protection regulations, and on the other hand, the low CTI value restricts the use of high-voltage electrical equipment and parts. The CTI value of the halogen-free flame-retardant nylon material can reach up to 600V, and it meets the requirements of environmental protection regulations, and is widely used in high-voltage electrical applications. During long-term use of halogen-free flame-retardant nylon materials, especially in hot and humid environments, halogen-free flame retardants are easy to precipitate and accumulate on the surface, causing accelerated aging of rubber seals in contact with it, and even brittleness, which leads to failure.

Patent CN201811440424.4 introduces a chain breaking agent into the hypophosphite flame-retardant nylon system to reduce the shearing of the flame retardant during the extrusion process, reduce the decomposition ratio of the flame retardant and the production of small molecules, thereby reducing the flame retardant Precipitation of flame retardants during use of nylon materials. Similarly, the patent CN201811440417.4 introduces substances that restrict the movement of nylon molecular chains, restricts moisture from entering and exiting the resin matrix, and further uses flame retardant precipitation inhibitors to generate water during extrusion to break nylon molecular chains and reduce flame retardants. The shear experienced during extrusion. Patent CN201911306473.3 uses a surface-modified nitrogen-based flame retardant and compounded a flame-retardant toughening agent with flame-retardant elements to improve the compatibility of flame-retardant components and nylon, and solve the problem of flame-retardant nylon products. The precipitation problem. However, when the nylon material that improves the precipitation of the flame retardant is in contact with the rubber sealing ring for a long time, the flame retardant contained in the flame retardant nylon material will still cause the rubber to degrade and harden.

Contents of the invention

The technical problem to be solved by the present invention is to provide a nylon material and its preparation method. By selecting a suitable free radical quencher and cooperating with an acid absorbing agent, the flame retardant that inhibits the precipitation of the halogen-free flame-retardant nylon material is essentially The degradation reaction of flame retardant and rubber is restrained.

The invention provides a nylon material, which comprises the following components in parts by mass:

Wherein, the free radical quencher is a hindered amine compound, the molecular structure is a tetramethylpiperidinyl derivative, and the molecular weight is 400-3100g/mol.

The tetramethylpiperidinyl derivatives can combine with the chain free radicals produced by the degradation of rubber affected by the flame retardant, thereby inhibiting the further degradation of rubber molecular chains.

The polyamide resin is at least one of PA66 and PA6 resins, with a relative viscosity of 2.0-3.2 (the test temperature is 25° C., and the solvent is 96% sulfuric acid). Preferably, the mass ratio of the PA66 to PA6 resin is 3-7:1.

The halogen-free flame retardant is at least one of red phosphorus, aluminum hypophosphite, aluminum diethylphosphinate, ammonium polyphosphate, melamine, and melamine cyanurate.

The glass fibers have an average diameter of 7-13 microns and an average length of 1.5-5 mm.

The thermal stabilizer is at least one of phenolic thermal stabilizers, thiosulfate esters, and aromatic amines.

The lubricant is at least one of hyperbranched polyester, stearate, ethylene bisstearamide and polyethylene wax.

The acid absorbing agent is at least one of zinc borate, hydrotalcite, anhydrous sodium carbonate, carbodiimide, polycarbodiimide, and alkaline earth metal carbonate. Zinc borate and hydrotalcite are preferred.

Preferably, 37.5-48.5 parts of the polyamide resin; 20-30 parts of glass fiber; 0.5-1.5 parts of free radical quencher; 0.5-1.5 parts of acid absorbing agent.

The present invention also provides a preparation method of a halogen-free flame-retardant nylon material, comprising the following steps:

Add the components into the mixer and mix them evenly to obtain a uniformly mixed material; extrude and granulate the mixed material through a twin-screw extruder to obtain a halogen-free flame-retardant nylon material; wherein, the temperature of the twin-screw extruder is set to The temperature is 220-280°C, and the screw speed is 200-600 rpm.

The invention also provides the application of a halogen-free flame-retardant nylon material in contact with rubber sealing rings, such as charging guns, charging sockets, connectors, etc. for new energy vehicles prepared from halogen-free flame-retardant nylon materials .

Beneficial effect

In the present invention, by selecting a suitable free radical quencher and cooperating with an acid absorbing agent, the acid absorbing agent can neutralize the small molecule phosphoric acid produced by the degradation of the flame retardant in the halogen-free flame retardant nylon material, thereby slowing down the acidic reaction of the rubber in contact with it. degradation under certain conditions; at the same time, since rubber cannot completely avoid the influence of flame retardants, a small amount of chain free radicals will be produced under the influence of flame retardants, and free radical quenchers can combine with the chain free radicals, thereby inhibiting the rubber molecule The chain is further degraded, so the present invention can satisfy that the rubber sealing ring still has good elasticity and sealing performance after long-term use and damp heat aging.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

The reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field unless otherwise specified.

The raw materials adopted in the following examples and comparative examples are as follows:

PA66 resin: from Huafon Group, typical grade EP-158, relative viscosity 2.7;

PA6 resin: from Haiyang Chemical Fiber, typical grade HY 2800, relative viscosity 2.8;

Glass fiber: from Chongqing Composite Materials, the grade is ECS301HP-3-H, the diameter is 10um, and the length is 3mm;

Heat stabilizer: phenolic heat stabilizer and thiosulfate antioxidant compounded at a mass ratio of 1:1;

Halogen-free flame retardant: compounded by aluminum diethylphosphinate and melamine cyanurate at a mass ratio of 3:1;

Aluminum diethylphosphinate, from Qingdao Opry New Material Co., Ltd., the typical brand is ADP-33P;

Melamine cyanurate, from Sichuan Fine Chemical Industry, the typical brand is MCA-01;

Free radical quencher 1: polymeric high molecular weight hindered amine compound, the typical brand is UV 944, the molecular weight is 2500g/mol;

Free radical quencher 2: low molecular weight hindered amine compound, the typical brand is UV 770, the molecular weight is 480g/mol; acid absorber 1: anhydrous sodium carbonate, the molecular weight is 106g/mol, chemically pure according to specifications;

Acid absorbent 2: zinc borate, molecular weight 314g/mol, chemically pure;

Lubricant: hyperbranched polyester, commercially available.

The composite materials of each embodiment and comparative example are prepared through the following process:

Add the components into the mixer and mix them evenly to obtain a uniformly mixed material; extrude and granulate the mixed material through a twin-screw extruder to obtain a halogen-free flame-retardant nylon material; wherein, the temperature of the twin-screw extruder is set to The temperature is 220-280°C, and the screw speed is 200-600 rpm.

Embodiment and comparative example are through following test method or test standard:

After combining silicone rubber with different contact materials, place it in a rubber compression set device (ASTM D395-2003, compression set, rubber standard sample is 6.0±0.2mm in height, 13.0±0.2mm in diameter cylinder), and further through accelerated aging Testing the thermal permanent deformation of rubber can quantitatively characterize the rebound performance of silicone rubber and reflect its sealing effect in actual use.

Vertical burning test: According to UL94 standard, the sample size is 125mm*13mm*1.6mm, 125mm*13mm*3.2mm.

Table 1 embodiment and comparative example formula

Table 2 embodiment and comparative example performance

The air heat aging deformation rate of the nylon material obtained in Examples 1-12 is 7.2%-15.3% at 168H, the air heat aging deformation rate is 11.3%-16.5% at 336H, and the air heat aging deformation rate is 16.1%-20.1% at 504H , 1000H air heat aging deformation rate of 20.9% -22.9%. The damp heat aging deformation rate is 7.1%-14.8% at 168H, the damp heat aging deformation rate is 11.8%-17.1% at 336H, the damp heat aging deformation rate is 14.3%-20.5% at 504H, and the damp heat aging deformation rate is 15.3%-24.1% at 1000H %.

Comparing Example 1 with Comparative Example 3, it can be seen that the silicone rubber is in contact with the halogen-free flame-retardant nylon material, and after aging at 150°C/1000H or 85°C/85% humidity, the permanent deformation of the silicone rubber reaches that of the rubber compression set device. The largest variable (40%), and hardening, loss of elasticity.

It can be seen from Example 1 and Comparative Examples 1 and 2 that the addition of a free radical quencher or an acid absorbing agent to the halogen-free flame-retardant nylon material reduces the amount of compression set after the aging of the silicone rubber in contact with it; while Example 1- 12. It can be seen that when the free radical quencher is used in combination with the acid absorber, the permanent deformation of the silicone rubber in contact with the halogen-free flame-retardant nylon material is further improved after aging.

Claims (10)

1. A nylon material, characterized in that: the coating comprises the following components in parts by weight:

wherein the free radical quencher is a hindered amine compound, the molecular structure is a tetramethyl piperidinyl derivative, and the molecular weight is 400-3100g/mol.

2. The nylon material of claim 1, wherein: the polyamide resin is at least one of PA66 and PA6 resin, and the relative viscosity is 2.0-3.2.

3. Nylon material according to claim 2, characterized in that: the mass ratio of the PA66 to the PA6 resin is 3-7:1.

4. The nylon material of claim 1, wherein: the halogen-free flame retardant is at least one of red phosphorus, aluminum hypophosphite, diethyl aluminum phosphinate, ammonium polyphosphate, melamine and melamine cyanurate.

5. The nylon material of claim 1, wherein: the average diameter of the glass fiber is 7-13 micrometers, and the average length is 1.5-5mm.

6. The nylon material of claim 1, wherein: the heat stabilizer is at least one of phenol heat stabilizer, thiosulfate and aromatic amine; the lubricant is at least one of hyperbranched polyester, stearate, ethylene bis-stearamide and polyethylene wax.

7. The nylon material of claim 1, wherein: the acid absorbing agent is at least one of zinc borate, hydrotalcite, anhydrous sodium carbonate, carbodiimide, polycarbodiimide and alkaline earth metal carbonate.

8. The nylon material of claim 1, wherein: 37.5-48.5 parts of polyamide resin; 20-30 parts of glass fiber; 0.5-1.5 parts of free radical quencher; 0.5-1.5 parts of acid absorber.

9. A method for preparing a nylon material according to any one of claims 1 to 8, comprising the steps of:

adding the components into a mixer for mixing; extruding and granulating the mixed materials by a double-screw extruder to obtain nylon materials; wherein the temperature of the twin-screw extruder is 220-280 ℃, and the screw rotating speed is 200-600 rpm.

10. Use of a nylon material according to any one of claims 1-8 in parts for use in contact with rubber sealing rings.