Nylon composite material as well as preparation method and application thereof

Abstract

The invention discloses a nylon composite material as well as a preparation method and application thereof, and belongs to the technical field of modified polymer composite materials. The nylon composite material comprises the following components in percentage by weight: 51%-61% of PA66 resin; 25%-30% of a halogen-free flame retardant glass fiber; 10%-18% of a flame retardant; 0.3%-0.6% of an antioxidant; 0.3%-0.6% of an efficient flow modifier; wherein the efficient flow modifier is selected from high molecular weight hyperbranched polyester containing aromatic groups. Through the combined action of the halogen-free flame-retardant glass fiber and the efficient flow modifier, the nylon composite material is excellent in mechanical property and flame retardant property, good in apparent quality, low in flame retardant content and low in cost, and the preparation method of the nylon composite material is simple, high in operability, wide in applicability and suitable for industrial production. The preparation process is halogen-free and more environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of modified polymer composite materials, in particular to a nylon composite material and a preparation method and application thereof. Background Art

[0002] Nylon is a combustible material that generates high heat during combustion, producing large amounts of thick smoke and flaming droplets, making it highly susceptible to flame propagation. The typical combustion process for nylon is as follows: it first melts and softens under flame heating. Further heating to a certain temperature causes the surface nylon to thermally decompose, breaking the molecular chains. The primary decomposition products of nylon 6 are caprolactam, while those of nylon 66 are cyclohexanone. Both also produce organic low-molecular-weight combustibles such as benzene, acetonitrile, and hydrocarbons with fewer than five carbon atoms. These compounds diffuse into the gas phase, providing fuel for combustion.

[0003] Glass fiber reinforced nylon (mainly nylon 66 or nylon 6) is more widely used than non-reinforced nylon because the introduction of glass fiber significantly improves the material's mechanical properties and heat distortion temperature. It is mainly used in the automotive industry, electronic appliances and other fields. However, due to the "wick effect" of glass fiber, at the combustion temperature, the polymer melt will wet and diffuse on the fiber surface, resulting in a rapid and directional flow of the polymer melt along the fiber surface to the fire zone (in short glass fiber reinforced nylon composite materials, if the fiber orientation is obvious, the directional flow effect is more obvious). This phenomenon will accelerate the fuel supply and intensify the combustion. In addition, in actual applications, most components require the modified nylon to have a UL94 flame retardant rating of V0. However, in the prior art, the UL94 flame retardant rating of glass fiber reinforced nylon materials is generally V2, thus limiting its scope of application.

[0004] Halogen-based flame retardants were initially highly regarded for their high flame retardancy, as the addition of flame retardants can improve the UL94 flame retardancy of nylon materials. However, the flame retardancy process of halogen-based flame retardants is accompanied by the volatilization of toxic gases. As people's environmental awareness grows, these halogen-based flame retardants are gradually being abandoned. In recent years, halogen-free flame retardants, such as nitrogen-based flame retardants, phosphorus-based flame retardants, and inorganic flame retardants, have become mainstream. However, existing halogen-free flame retardants suffer from issues such as large addition dosages and poor compatibility with the matrix resin and reinforcing components. This makes melt processing difficult, resulting in poor product appearance and low flame retardancy.

[0005] To address these issues, flame retardants are typically modified physically or chemically, or compounded. For example, Chinese patent CN100410324C describes the use of ultrafine metal ion-modified melamine polyphosphate (M-MPP) as a halogen-free flame retardant. This improves the poor compatibility of flame retardants with PA66, resulting in a glass fiber-reinforced flame-retardant nylon 66 material with excellent mechanical and flame retardant properties. While the methods described in these patents have some impact on addressing the issues associated with halogen-free flame retardants, they also suffer from complex formulations and limited applicability. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a nylon composite material and its preparation method and application. The nylon composite material has excellent mechanical properties, good surface quality, low flame retardant content and low cost.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a nylon composite material, comprising the following components by weight:

[0009] PA66 resin: 51%-61%;

[0010] Halogen-free flame retardant glass fiber: 25%-30%;

[0011] Flame retardant: 10%-18%;

[0012] Antioxidant: 0.3%-0.6%;

[0013] High-efficiency flow modifier: 0.3%-0.6%;

[0014] Wherein, the high-efficiency flow modifier is selected from high molecular weight hyperbranched polyester containing aromatic groups.

[0015] More preferably, the content of the PA66 resin is 55%-61%; further preferably, it is 59.2%, 57%, 55% or 60.3%.

[0016] More preferably, the content of the halogen-free flame-retardant glass fiber is 25%-30%, and further preferably 25% or 30%.

[0017] More preferably, the content of the flame retardant is 10%-14%; further preferably, it is 10%, 12% or 14%.

[0018] More preferably, the content of the antioxidant is 0.3%-0.4%; further preferably 0.3% or 0.4%.

[0019] More preferably, the content of the high-efficiency flow modifier is 0.3%-0.6%; further preferably, it is 0.3%, 0.5% or 0.6%.

[0020] The present invention further preferably comprises the following components by weight percentage:

[0021] PA66 resin: 59.2%;

[0022] Halogen-free flame retardant glass fiber: 30%;

[0023] Flame retardant: 10%;

[0024] Antioxidant: 0.3%;

[0025] High efficiency flow improver: 0.5%;

[0026] Wherein, the high-efficiency flow modifier is selected from high molecular weight hyperbranched polyester containing aromatic groups.

[0027] Alternatively, the present invention further preferably comprises the following components by weight percentage:

[0028] PA66 resin: 57%;

[0029] Halogen-free flame retardant glass fiber: 30%;

[0030] Flame retardant: 12%;

[0031] Antioxidant: 0.4%;

[0032] High efficiency flow improver: 0.6%;

[0033] Wherein, the high-efficiency flow modifier is selected from high molecular weight hyperbranched polyester containing aromatic groups.

[0034] Alternatively, the present invention further preferably comprises the following components by weight percentage:

[0035] PA66 resin: 55%;

[0036] Halogen-free flame retardant glass fiber: 30%;

[0037] Flame retardant: 14%;

[0038] Antioxidant: 0.4%;

[0039] High efficiency flow improver: 0.6%;

[0040] Wherein, the high-efficiency flow modifier is selected from high molecular weight hyperbranched polyester containing aromatic groups.

[0041] Alternatively, the present invention further preferably comprises the following components by weight percentage:

[0042] PA66 resin: 60.3%;

[0043] Halogen-free flame retardant glass fiber: 25%;

[0044] Flame retardant: 14%;

[0045] Antioxidant: 0.4%;

[0046] High efficiency flow improver: 0.3%;

[0047] Wherein, the high-efficiency flow modifier is selected from high molecular weight hyperbranched polyester containing aromatic groups.

[0048] In the nylon composite material described in the present invention, the high-efficiency flow modifier, due to its special structure, allows it to slide in a spherical structure between nylon molecular chains, which can effectively improve the fluidity of the nylon composite material during processing, improve the melt index and sliding performance, and is more conducive to the tumbling of glass fibers, making the glass fiber distribution more disordered, weakening the "wick effect" of glass fibers from the perspective of glass fiber orientation, and improving flame retardant efficiency.

[0049] In the present invention, the high molecular weight hyperbranched polyester containing aromatic groups is selected from HyPer C181, HyPer C100 or HyPer C182; more preferably HyPer C181.

[0050] In the nylon composite material described in the present invention, the surface of the halogen-free flame-retardant glass fiber is loaded with a flame retardant, which can be dispersed along with the glass fiber during the injection molding process. Compared with the flame retardant added to the resin, it has better dispersibility and higher flame retardant efficiency, so it can effectively reduce the amount of flame retardant added to the resin.

[0051] Preferably, the halogen-free flame-retardant glass fiber is selected from ECS301FR.

[0052] It is further preferred in the present invention that the halogen-free flame-retardant glass fiber has a length of 3-6 mm and a diameter of 5-24 μm;

[0053] Further preferably, the relative viscosity of the PA66 resin is 2.0-3.5.

[0054] Preferably, the flame retardant is selected from organic phosphinate halogen-free flame retardants.

[0055] In the present invention, the organic phosphinate halogen-free flame retardant is preferably selected from aluminum diethylphosphinate or zinc diethylphosphinate; more preferably aluminum diethylphosphinate.

[0056] In the present invention, the antioxidant is preferably selected from one or more of hindered phenol antioxidants, amine antioxidants, and phosphate antioxidants.

[0057] The hindered phenol antioxidants include, but are not limited to, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine, and the like.

[0058] The amine antioxidants include but are not limited to 4,4'-diphenylamine, 4-tert-butyldiphenylamine, stearamide, N,N-di-sec-butyl-p-phenylenediamine, and the like.

[0059] The phosphate antioxidants include but are not limited to tris[2,4-di-tert-butylphenyl]phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumyl)diphosphite, and the like.

[0060] The present invention also provides a method for preparing the above-mentioned nylon composite material, comprising the following steps:

[0061] (1) mixing PA66 resin, flame retardant, antioxidant and high-efficiency flow modifier according to the weight percentages to obtain a mixture S1;

[0062] (2) The mixture S1 and the halogen-free flame-retardant glass fiber are uniformly mixed by screw shearing, and then extruded, pulled, cooled, and pelletized to obtain the nylon composite material. Preferably, the nylon composite material is prepared using a twin-screw extruder;

[0063] Preferably, the screw aspect ratio of the twin-screw extruder is (40-48):1, and the barrel temperature is 240°C-285°C.

[0064] In some specific embodiments of the present invention, the method for preparing the nylon composite material comprises the following steps:

[0065] (1) Weigh PA66 resin, flame retardant, antioxidant, and high-efficiency flow modifier according to weight percentage, mix them evenly, and obtain a premix;

[0066] (2) The premix is fed into the main feed port of a twin-screw extruder, and halogen-free flame-retardant glass fiber is added to the side feed port. After shearing by the screw, the premix and the sheared glass fiber are fully mixed. After extrusion, pulling, cooling, and pelletizing, the nylon composite material is obtained.

[0067] The present invention also provides the use of the above-mentioned nylon composite material or the nylon composite material prepared by the above-mentioned preparation method in electronic appliances or connectors.

[0068] Compared with the prior art, the nylon composite material provided by the present invention comprises the following components, by weight percentage: PA66 resin: 51%-61%; halogen-free flame-retardant glass fiber: 25%-30%; flame retardant: 10%-18%; antioxidant: 0.3%-0.6%; and high-efficiency flow modifier: 0.3%-0.6%; wherein the high-efficiency flow modifier is selected from a high-molecular-weight hyperbranched polyester containing aromatic groups. Through the combined action of the halogen-free flame-retardant glass fiber and the high-efficiency flow modifier, the present invention achieves excellent mechanical and flame-retardant properties, good surface quality, low flame retardant content, and low cost. Furthermore, the preparation method of the nylon composite material is simple, highly operable, and widely applicable, and the preparation process uses halogen-free raw materials, making it more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a diagram showing the distribution of glass fibers in the composite material prepared in Example 1;

[0070] Figure 2 This is a diagram of the glass fiber distribution state in the composite material prepared in Comparative Example 3. DETAILED DESCRIPTION

[0071] To further illustrate the present invention, the nylon composite material provided by the present invention, its preparation method and application are described in detail below with reference to the embodiments.

[0072] The sources of the raw materials used are as follows:

[0073] PA66 resin: 101L, DuPont, USA, relative viscosity 2.0-3.5;

[0074] Halogen-free flame-retardant glass fiber: ECS301FR, Chongqing International Composite Materials Co., Ltd.

[0075] Ordinary glass fiber: ECS301HP-3-H, Chongqing International Composite Materials Co., Ltd.

[0076] Flame retardant: Exolit OP 1314, Clariant, Germany, its main component is aluminum diethylphosphinate;

[0077] Antioxidants: antioxidant 168 and antioxidant 1010 (mixed in a mass ratio of 1:1), Ciba Specialty Chemicals, Switzerland;

[0078] Lubricant A: HyPer C181, Wuhan Hyperbranched Resin Technology Co., Ltd., a high molecular weight hyperbranched polyester containing aromatic groups;

[0079] Lubricant B: PETS, Shanghai Jinghong Chemical Technology Co., Ltd. This product is not a high molecular weight hyperbranched polyester containing an aromatic chemical structure;

[0080] Extrusion granulation was performed according to the formulations and dosages of the specific examples and comparative examples described in Table 1, and the resulting composite particles were then injection molded into standard bars. Tensile bars were prepared according to ISO 527 standard bar dimensions; flexural strength and flexural modulus were prepared according to ISO 178 standard bar dimensions; impact bars were prepared according to ISO 180 standard bar dimensions; and flame retardant test bars were prepared with dimensions of 125 mm * 13 mm * 3.2 mm, 125 mm * 13 mm * 1.6 mm, and 125 mm * 13 mm * 0.8 mm.

[0081] Table 1 Amount of each component used in the examples and comparative examples (unit: kg)

[0082]

[0083] The flame retardant glass fiber reinforced PA66 composite materials prepared in the above specific examples and comparative examples were subjected to performance tests, and the test standards were as follows:

[0084] Tensile properties: According to GB / T1040-2006 national standard for the determination of tensile properties of plastics ISO 527-1 / -2, the speed is 20mm / min;

[0085] Bending properties: According to GB / T9341-2008 national standard for the determination of bending properties of plastics ISO 178:2010, the speed is 20mm / min;

[0086] Notched impact test: in accordance with GB / T1843-2008 national standard for the determination of the cantilever beam impact strength of plastics ISO180:2010 / 1Ea, the speed is 3.5m / s;

[0087] Unnotched impact test: in accordance with GB / T1843-2008 national standard for the determination of the cantilever beam impact strength of plastics ISO180:2010 / 1Eu, the speed is 3.5m / s;

[0088] Flame retardant performance: The flame retardancy of the material is tested according to the method in UL94. The flame retardant specimens are subjected to a vertical burning test. The evaluation grades are V0, V1 and V2. The smaller the value, the better the flame retardant performance.

[0089] The apparent quality is visually inspected using a 150mm*100mm*3mm flat plate.

[0090] Table 2 Test results of the embodiments and comparative examples

[0091]

[0092]

[0093] The test results of the examples and comparative examples in Table 2 above show that the use of flame-retardant glass fiber and high-efficiency flow modifier can greatly reduce the amount of flame retardant used in the composite material. Comparing Example 1 and Comparative Example 3, at a glass fiber content of 30%, the composite material prepared using ordinary glass fiber and ordinary lubricant needs to add 18% of flame retardant to reach V0 (1.6mm), while the composite material prepared using flame-retardant glass fiber and high-efficiency flow modifier only needs to add 10% of flame retardant to reach V0 (0.8mm). The composite material also has higher mechanical strength and better apparent quality, and the production cost can be greatly reduced. In addition, from Figure 1 It can be seen that the glass fiber distribution in the composite material prepared in Example 1 is disordered, while Figure 2 The glass fiber orientation in the composite material prepared in Comparative Example 3 is obvious.

[0094] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A nylon composite material, characterized in that: Calculated by weight percentage, it includes the following components: PA66 resin: 51%-61%; Halogen-free flame retardant glass fiber: 25%-30%; Flame retardant: 10%-18%; Antioxidant: 0.3%-0.6%; High-efficiency flow modifier: 0.3%-0.6%; Wherein, the high-efficiency flow modifier is selected from high molecular weight hyperbranched polyester containing aromatic groups.

2. The nylon composite material according to claim 1, characterized in that The high molecular weight hyperbranched polyester containing aromatic groups is selected from HyPer C181, HyPer C100 or HyPer C182.

3. The nylon composite material according to claim 1, characterized in that The halogen-free flame-retardant glass fiber is ECS301FR.

4. The nylon composite material according to claim 1 or 3, characterized in that: The halogen-free flame-retardant glass fiber has a length of 3-6 mm and a diameter of 5-24 μm; The relative viscosity of the PA66 resin is 2.0-3.

5.

5. The nylon composite material according to claim 1, characterized in that The flame retardant is selected from organic phosphinate halogen-free flame retardants.

6. The nylon composite material according to claim 5, characterized in that: The organic phosphinate halogen-free flame retardant is selected from aluminum diethylphosphinate or zinc diethylphosphinate.

7. The nylon composite material according to claim 1, characterized in that The antioxidant is selected from one or more of hindered phenol antioxidants, amine antioxidants, and phosphate antioxidants.

8. The method for preparing the nylon composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) mixing PA66 resin, flame retardant, antioxidant and high-efficiency flow modifier according to the weight percentages to obtain a mixture S1; (2) The mixture S1 and the halogen-free flame-retardant glass fiber are mixed uniformly by screw shearing, and then extruded, pulled, cooled, and pelletized to obtain the nylon composite material.

9. The preparation method according to claim 8, characterized in that The nylon composite material is prepared by using a twin-screw extruder; The twin-screw extruder has a screw length-diameter ratio of (40-48):1, and a screw barrel temperature of 240°C-285°C.

10. Use of the nylon composite material according to any one of claims 1 to 7 or the nylon composite material prepared by the preparation method according to claim 8 or 9 in the field of electronic appliances or connectors.

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