Photobrominated polyamide composite material, and preparation method and application thereof

Abstract

The application belongs to the technical field of high polymer flame-retardant materials, and discloses a photo-induced flame-retardant polyamide composite adopting a photo-responsive BDP flame retardant, a preparation method and application thereof.The photo-induced flame-retardant polyamide composite comprises the following components by weight percentage: a polyamide matrix: 79-97.8%; a photo-responsive BDP flame retardant: 2-10%; OP1230: 0-10%; an antioxidant: 0.1-0.5%; and a release agent: 0.1-0.5%.The preparation method is to mix raw materials, granulate through an extruder, then injection molding, and then make the benzophenone group initiate cross-linking reaction under light and heat conditions to form a dense flame-retardant covering layer.The surface cross-linking layer blocks the transmission of oxygen and combustible materials, the oxygen index (LOI) can reach more than 30%, the UL94 flame-retardant grade reaches V-0 level, which is superior to the conventional BDP system and OP system with the same addition amount.

Description

Technical Field

[0001] This invention belongs to the field of polymer flame retardant materials technology, and specifically relates to a photo-retardant polyamide composite material using a photoresponsive BDP flame retardant, its preparation method, and its application. Background Technology

[0002] Polyamide materials (such as nylon 6 and nylon 66) are widely used in electronics, automotive parts, and other fields due to their excellent mechanical properties and processability. However, their inherent flammability limits their application in high-risk environments. Existing halogen-free flame retardant systems for polyamides mainly use OP series flame retardants, which require large addition amounts (generally greater than or equal to 20% by mass), resulting in high costs and significant impacts on mechanical properties. Bisphenol A bis(diphenyl phosphate) (BDP) is a commonly used halogen-free flame retardant, widely used due to its low price and good thermal stability. However, BDP is not suitable for polyamides because conventional BDP has poor compatibility with polyamides; even slightly high addition amounts can easily lead to precipitation, causing serious quality problems in the appearance of the manufactured parts. Furthermore, BDP has a low phosphorus content, resulting in insufficient flame retardant efficiency for polyamides.

[0003] Developing a method that can effectively utilize the exudation characteristics of BDP in polyamide to achieve highly efficient flame retardancy in polyester would be of great significance and practical value. Summary of the Invention

[0004] To overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide a photo-induced flame-retardant polyamide composite material. Utilizing the characteristic that BDP easily migrates and precipitates in polyamide upon heating, combined with a photo-induced crosslinking reaction, a dense flame-retardant layer rich in flame retardant is formed on the material surface, achieving high-efficiency flame retardancy with low addition levels while maintaining the mechanical properties of the polyamide matrix.

[0005] Another objective of this invention is to provide a method for preparing the above-mentioned photo-induced flame-retardant polyamide composite material.

[0006] Another object of the present invention is to provide the application of the above-mentioned photo-induced flame-retardant polyamide composite material.

[0007] The objective of this invention is achieved through the following solution:

[0008] A photo-induced flame-retardant polyamide composite material comprising the following components by weight percentage:

[0009] Polyamide matrix: 79-97.8%;

[0010] Photoresponsive BDP flame retardant: 2-10%;

[0011] OP1230: 0-10%;

[0012] Antioxidant: 0.1-0.5%;

[0013] Release agent: 0.1-0.5%.

[0014] Preferably, the photo-induced flame-retardant polyamide composite material comprises the following components by weight percentage:

[0015] Polyamide matrix: 88-92.8%;

[0016] Photoresponsive BDP flame retardant: 3-5%;

[0017] OP1230: 4-6%;

[0018] Antioxidant: 0.1-0.5%;

[0019] Release agent: 0.1-0.5%.

[0020] The photoresponsive BDP flame retardant has at least one of the following structural formulas:

[0021]

[0022] Where n is an integer from 1 to 5;

[0023] Preferably, n is mainly 1, but also contains integers n=2-5.

[0024] The photoresponsive BDP flame retardant is prepared by the following method:

[0025] Phosphorus oxychloride and bisphenol A were used as raw materials to generate an intermediate. After removing excess phosphorus oxychloride by negative pressure evaporation, 4-hydroxybenzophenone was added, followed by end-capping reaction. After the reaction was completed, the target product was obtained by alkali washing and water washing.

[0026] The reaction intermediate refers to the reaction being carried out under reflux at 65-80℃ for 3-5 hours.

[0027] Preferably, the reaction for generating the intermediate can also be carried out under catalytic conditions, wherein the catalyst is a cationic resin, preferably an H-type macroporous cationic resin.

[0028] The molar ratio of bisphenol A, phosphorus oxychloride, and 4-hydroxybenzophenone is 1:(3-8):(2.05-2.2); the amount of catalyst used is 2%-8% of the mass of bisphenol A.

[0029] The addition of 4-hydroxybenzophenone is preferably done dropwise, with the dropwise addition time controlled at 1-1.5 hours;

[0030] The capping reaction refers to heating to 110-140℃ and reacting for 1-4 hours. After the reaction is complete, the mixture is diluted with toluene, followed by alkali washing and water washing.

[0031] The polyamide matrix is ​​at least one of PA66 and PA6;

[0032] The antioxidant is at least one of hindered phenolic antioxidants and hindered amine antioxidants.

[0033] The release agent is at least one of stearate release agents and stearamide release agents, preferably pentaerythritol stearate PETS.

[0034] A method for preparing the above-mentioned photo-induced flame-retardant polyamide composite material includes the following steps:

[0035] (1) Extrusion: The polyamide matrix, photoresponsive BDP flame retardant, OP1230, antioxidant and release agent are added to a twin-screw extruder, melt-blended at 230-290℃, and then extruded and granulated.

[0036] (2) Injection molding: The granules extruded in step (1) are injection molded at a processing temperature of 240-290℃;

[0037] (3) Photocrosslinking: The injection-molded sample is placed in a UV box with heating function and irradiated with light while being heated to obtain photo-induced flame-retardant polyester composite material.

[0038] The heating temperature mentioned in step (3) is 70-140℃; the irradiation refers to irradiating the surface of the injection-molded sample with a 365nm UV lamp at an intensity of 80-120mW / cm², with intermittent irradiation, each irradiation lasting 10-30 seconds, with an interval of 20-40 minutes between irradiations, for a total time of 4-8 hours. This causes the benzophenone groups to initiate a cross-linking reaction, forming a dense flame-retardant coating layer.

[0039] The above-mentioned photo-induced flame-retardant polyamide composite materials are used in electronic devices, consumer electronics, medical equipment, and automobiles.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] (1) Excellent flame retardant performance: The surface cross-linking layer blocks the transmission of oxygen and combustibles, and the oxygen index (LOI) can reach more than 30%. The UL94 flame retardant rating reaches V-0, which is better than the conventional BDP system and OP system with the same amount of additive.

[0042] (2) Good mechanical properties: After BDP is enriched on the surface, the matrix purity is high and the notched impact strength retention rate is ≥90%, which solves the performance degradation problem caused by traditional flame retardants.

[0043] (3) Controllable process: Heating precipitation and UV crosslinking are both post-processing treatments, compatible with existing polyamide molding equipment, and require no special modification. Attached Figure Description

[0044] Figure 1 The infrared spectrum of the photoresponsive BDP flame retardant prepared in Example 1 is shown. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0046] Unless otherwise specified, all reagents used in the examples are commercially available.

[0047] Example 1

[0048] Flame retardant preparation: 4.57 kg (20 mol) of bisphenol A and 0.23 kg of H-type macroporous cation exchange resin (Amberlyst 15) were added to a 50 L reactor. Under mechanical stirring (200-300 r / min), 15.33 kg (100 mol) of phosphorus oxychloride was slowly added over 1 hour. After addition, the temperature was raised to 70 °C and refluxed at atmospheric pressure for 3 hours (with a tail gas absorption device connected to the top of the condenser to absorb HCl gas) until no obvious HCl gas escaped from the spherical condenser. Stirring was maintained, the vacuum pump was turned on, and the vacuum degree was controlled at 0.1 MPa. The temperature was controlled at 60-70 °C, and distillation was carried out for 1.5-2 hours to remove excess phosphorus oxychloride. The temperature was then controlled to 80 °C, and 8.13 kg (41 mol) of 4-hydroxybenzophenone was slowly added over 1 hour. After addition, the temperature was raised to 120 °C and the reaction was maintained for 3 hours. The temperature was then lowered to 50 °C, and 10 L of toluene was added for dilution. The sample was washed successively with 5% sodium carbonate aqueous solution (6 L × 2 times) and deionized water (6 L × 3 times). After standing and separating into layers, the organic phase was collected and toluene was removed by vacuum distillation to obtain a pale yellow viscous liquid product, a photoresponsive BDP flame retardant. The infrared spectrum of the photoresponsive BDP flame retardant is attached. Figure 1 3340cm -1 The peak at 1628 cm⁻¹ is a characteristic peak of the benzene ring in benzophenone. -1 The peak at this point is the carbonyl peak of benzophenone, proving that the photoresponsive BDP flame retardant has been successfully synthesized.

[0049] Comparative Examples 1-2 and Examples 2-13:

[0050] Extrusion: Polyamide particles (PA66 is BASF Ultramid A3K, PA6 is BASFU Ultramid B3S), flame retardant (at least one of the photoresponsive BDP flame retardant prepared in Example 1, BDP (Wansheng WSFR-BDP) or OP1230 (Clariant), antioxidant 1010, and mold release agent PETS are added to a twin-screw extruder according to the weight percentages in Table 1, melt-blended at 230-290°C, and extruded and granulated.

[0051] Injection molding: The granules are vacuum dried at 80 degrees Celsius for 4 hours, and then injection molded at a processing temperature of 240-290 degrees Celsius.

[0052] Photocrosslinking: The injection-molded sample was placed in a UV chamber with heating function and heated to 120℃. At the same time, a 365nm UV lamp was used to irradiate the surface of the part at an intensity of 100mW / cm². Irradiation was performed at intervals, with each irradiation lasting 20 seconds and an interval of 30 minutes between irradiations, for a total duration of 6 hours.

[0053] Mechanical properties and flame retardancy tests were performed on the photocrosslinked samples. Tensile testing was performed according to ISO 527-2, notched impact strength according to ISO 179 / 1eA; heat distortion temperature testing according to ISO 75-2; LOI testing according to ISO 4598-2; flame retardancy testing according to UL 94; surface exudation was detected by wiping directly with a paper towel, and exudation occurred if liquid was present; otherwise, no exudation occurred.

[0054] Table 1. Weight percentage (wt%) of each component in Comparative Examples 1-2 and Examples 2-13 and the properties of the resulting samples

[0055]

[0056] The data shows that, compared to flame retardants BDP and OP1230, photoresponsive BDP flame retardant has minimal impact on the mechanical properties of the material while exhibiting high flame retardant efficiency. As the content of photoresponsive BDP flame retardant increases, the flame retardant performance of the material gradually improves. At the same addition ratio, photoresponsive BDP flame retardant demonstrates significantly higher flame retardant performance than ordinary BDP and OP1230, while maintaining mechanical properties.

[0057] In addition, when photoresponsive BDP flame retardant and OP1230 are combined, as in Examples 7 and 13, the two can produce a synergistic effect, further improving the flame retardancy of the material.

[0058] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A photo-induced flame-retardant polyamide composite material, characterized in that, It consists of the following components by weight percentage: PA66: 79-97.8%; Photoresponsive BDP flame retardant: 5%; OP1230: 4%; Antioxidant: 0.1-0.5%; Release agent: 0.1-0.5%; The sum of the weight percentages of all components is 100%; The photoresponsive BDP flame retardant has at least one of the following structural formulas: ; Where n is an integer from 1 to 5.

2. A photo-induced flame-retardant polyamide composite material, characterized in that, It consists of the following components by weight percentage: PA6: 79-97.8%; Photoresponsive BDP flame retardant: 3%; OP1230: 6%; Antioxidant: 0.1-0.5%; Release agent: 0.1-0.5%; The sum of the weight percentages of all components is 100%; The photoresponsive BDP flame retardant has at least one of the following structural formulas: ; Where n is an integer from 1 to 5.

3. The photo-induced flame-retardant polyamide composite material according to claim 1 or 2, characterized in that: The photoresponsive BDP flame retardant is prepared by the following method: phosphorus oxychloride and bisphenol A are reacted to generate an intermediate; after removing excess phosphorus oxychloride under negative pressure, 4-hydroxybenzophenone is added, and then an end-capping reaction is carried out. After the reaction is completed, the target product is obtained by purification.

4. The photo-induced flame-retardant polyamide composite material according to claim 3, characterized in that: The reaction intermediate refers to the reaction being carried out under reflux at 65-80℃ for 3-5 hours; The capping reaction refers to heating to 110-140℃ and reacting for 1-4 hours.

5. The photo-induced flame-retardant polyamide composite material according to claim 3, characterized in that: The reaction that generates the intermediate is carried out under catalytic conditions, and the catalyst is a cationic resin.

6. The photo-induced flame-retardant polyamide composite material according to claim 3, characterized in that: The molar ratio of bisphenol A, phosphorus oxychloride and 4-hydroxybenzophenone is 1:(3-8):(2.05-2.2); when a catalyst is present, the amount of the catalyst is 2%-8% of the mass of bisphenol A.

7. The photo-induced flame-retardant polyamide composite material according to claim 1 or 2, characterized in that: The antioxidant is at least one of hindered phenolic antioxidants and hindered amine antioxidants; The release agent is at least one of stearate ester release agents and stearamide release agents.

8. A method for preparing a photo-induced flame-retardant polyamide composite material according to any one of claims 1-7, characterized in that... Includes the following steps: (1) Extrusion: PA66 or PA6, photoresponsive BDP flame retardant, OP1230, antioxidant and release agent are added to a twin-screw extruder, melt-blended at 230-290℃, and then extruded and granulated. (2) Injection molding: The granules extruded in step (1) are injection molded at a processing temperature of 240-290℃; (3) Photocrosslinking: The injection-molded sample is placed in a UV box with heating function and irradiated with light while being heated to obtain photo-induced flame-retardant polyester composite material.

9. The method for preparing the photo-induced flame-retardant polyamide composite material according to claim 8, characterized in that: The heating temperature mentioned in step (3) is 70-140℃; the light irradiation refers to using a 365nm UV lamp to irradiate the surface of the injection-molded sample with an intensity of 80-120mW / cm². The irradiation is done in intervals, each time for 10-30s, with an interval of 20-40min between two irradiations, for a total time of 4-8h.

10. The application of the photo-induced flame-retardant polyamide composite material according to any one of claims 1-7 in electronic devices, consumer electronics, medical devices, and automobiles.

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