Aging-resistant decorative frame for vehicle lamp and preparation method thereof

Abstract

The application discloses an anti-aging decorative frame for vehicle lamps and a preparation method thereof, and relates to the technical field of vehicle lamp decorative rings, which comprises injection molding to form a base body, metal film plating to form a metal film, and upper protective film forming to form a protective film; the base body comprises PC, ABS, PBT, a compatibilizer, a filler, an antioxidant and an ester exchange inhibitor; the ABS is modified by an alkenyl compound and methyl methacrylate; the alkenyl compound is prepared from diisocyanate, 2-(4-aminophenyl)-5-benzotriazole amine and hydroxyethyl acrylate. The polycarbonate, acrylonitrile-butadiene-styrene and polybutylene terephthalate are compounded to serve as a base polymer material system, so that the application has excellent mechanical properties, processing properties, thermal stability and chemical stability. Through modification of the ABS, the compatibility of the system is improved, the mechanical properties, ultraviolet resistance and heat resistance of the base body are improved, and the surface quality is improved.

Description

Technical Field

[0001] This invention relates to the field of automotive lamp trim technology, specifically to an aging-resistant decorative frame for automotive lamps and its preparation method. Background Technology

[0002] With the trend towards lightweighting in automobiles, polymer materials are increasingly being used. Automotive headlight trim rings, as functional exterior components, have become an important part of personalized automotive design. Most headlight trim rings are aluminum-plated. However, due to poor adhesion between the substrate and the aluminum layer, and a large difference in expansion and absorption, the aluminum film can crack during use. Furthermore, directly plating aluminum onto the substrate results in a poor-looking aluminum film. Therefore, a primer is typically applied to the substrate before aluminum plating. However, the evaporation of primer solvents causes environmental pollution, complicates the process, increases costs and timelines, and hinders recycling, limiting design freedom. In headlight trim rings without a primer, the lack of isolation between the substrate and the aluminum film allows small molecules in the substrate to migrate under prolonged use or thermal stress, affecting the quality of the aluminum film. Therefore, we propose an aging-resistant decorative frame for automotive headlights and its preparation method. Summary of the Invention

[0003] The purpose of this invention is to provide an aging-resistant decorative frame for automotive lights and its manufacturing method, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an aging-resistant decorative frame for vehicle lights, comprising the following structures from the inside out: a substrate, a metal film, and a protective film.

[0005] Furthermore, the matrix is ​​a polymer material, specifically one or a mixture of polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polybenzothiazole (PBT), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide (PI), and thermosetting plastics (BMC).

[0006] Furthermore, the thickness of the metal film is 200 nm to 10 μm.

[0007] Furthermore, the protective film is one or more of the following: metal oxide, non-metal oxide, and organosilicon.

[0008] Furthermore, the thickness of the protective film is 80nm to 2.5μm.

[0009] A method for preparing an aging-resistant decorative frame for automotive lights includes injection molding, metal plating, and applying a protective film, wherein a substrate, a metal film, and a protective film are formed sequentially.

[0010] Furthermore, the matrix comprises the following components by weight: 50-70 parts PC, 30-40 parts ABS, 5-20 parts PBT, 0-10 parts compatibilizer, 0.3-1.0 parts filler, 0.2-2.0 parts antioxidant, and 0-2.0 parts transesterification inhibitor.

[0011] In the above technical solutions, polycarbonate (PC) contains carbonate groups in its molecular chain, possessing excellent mechanical properties and good adhesion to metal films, allowing for direct aluminum plating. Adding acrylonitrile-butadiene-styrene (ABS) in combination with PC can reduce the internal stress of the prepared matrix and decrease its sensitivity to notches; it can also reduce the viscosity of the PC melt, improve the processing performance of the polymer system, and enhance the overall performance of the prepared matrix. Polybutylene terephthalate (PBT) possesses good self-lubricating properties, thermal stability, and chemical stability, and exhibits high rigidity and hardness, as well as good impact resistance, dimensional stability, and heat resistance, further improving the overall mechanical, processing, and heat resistance properties of the prepared matrix.

[0012] Furthermore, the compatibilizer is one of maleic anhydride-grafted ABS, maleic anhydride-styrene copolymer (SMA), or methyl methacrylate-butadiene-styrene copolymer (MBS).

[0013] In the above technical solution, the compatibilizer can improve the compatibility between PC, PBT and ABS to a certain extent, so that the properties of the composite material made from the three can be fully utilized, thereby improving the overall performance of the matrix.

[0014] Furthermore, the filler is one or a mixture of carbon fiber, glass fiber, aluminosilicate, barium sulfate, silicon dioxide, and alumina.

[0015] In the above technical solution, adding fillers to polymer materials can improve the mechanical and processing properties of the matrix; it can also act as a nucleating agent, improving the crystallinity of the material, thereby further improving the heat resistance of the matrix. Furthermore, aluminosilicates with mesoporous structures can absorb small molecules, reducing their volatilization and contributing to improved aluminum film quality.

[0016] Furthermore, the antioxidant is one or a mixture of two of Irganox 245 and Irganox 168.

[0017] Furthermore, the transesterification inhibitor is one or a mixture of sodium dihydrogen phosphate, triphenyl phosphite, sodium hexametaphosphate, and sodium pyrophosphate.

[0018] In the above technical solution, the addition of transesterification inhibitors reduces the occurrence of transesterification reactions in the polymer system, preventing the disruption of the regularity of the PET molecular chains. Under the action of transesterification inhibitors, the transesterification reaction mainly generates long-chain block copolymers, which to some extent improves the compatibility of the polymer blend system and enhances the crystallinity, interfacial adhesion, and thermal stability of the polymer system. However, the use of the aforementioned transesterification inhibitors will generate small molecule volatiles, causing the aluminum film surface to become dull, exhibit iridescent phenomena, and become foggy.

[0019] Furthermore, the ABS undergoes modification, with the specific process as follows:

[0020] ABS and initiator are mixed, and alkenyl compounds and methyl methacrylate are added. The mixture is then melt-extruded at an extruder temperature of 140–220°C and a die temperature of 195–205°C. After drying, modified ABS is obtained.

[0021] Furthermore, the modified ABS comprises the following components by weight: 100 parts ABS, 4-15 parts alkenyl compound, 15-30 parts methyl methacrylate, and 0.3-0.5 parts initiator;

[0022] The initiator is dicumyl peroxide.

[0023] In the above technical solution, methyl methacrylate (MMA) has high molecular polarity, and its polarity and solubility parameters are quite similar to those of PC. Compared with adding a compatibilizer, directly adding MMA to ABS by grafting is beneficial to improving interfacial bonding, making the modified ABS easier to disperse in PC and PBT, with stronger interfacial bonding, and improving the impact strength of the polymer material system.

[0024] Furthermore, the alkenyl compounds are prepared by the following process:

[0025] S1. Under a nitrogen atmosphere, diisocyanate and 3-methyl-1-phenylphosphazene-1-oxide are mixed, heated to 160-165°C, and reacted for 10-20 h to obtain isocyanate-based diimine carbonate.

[0026] S2. Mix 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate in deionized water and stir for 100-150 min; heat to 94-98℃ and reflux the reaction solution for 12 h; cool, filter and dry to obtain thiourea compound;

[0027] Thiourea compound and polyethylene glycol were mixed in toluene, heated to 70-75°C, sodium hypochlorite was added, and the reaction was carried out for 90-120 min; sodium hydroxide was added, the temperature was raised to 80-90°C, and the reaction was carried out for 60-90 min; the mixture was washed, rotary evaporated, and crystallized to obtain phenyltriazolyldiamine.

[0028] S3. Mix isocyanate-based diimide carbonate and phenyltriazolyl diamine, heat to 20-50°C, add catalyst, and react for 10-30 min; add hydroxyethyl acrylate, heat to 80-85°C, and react for 10-30 min to obtain alkenyl compound.

[0029] Furthermore, in S1, the diisocyanate is one of cyclohexane-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 4,4-diisocyanate dicyclohexylmethane, dimethylbiphenyl diisocyanate, isophorone diisocyanate, toluene diisocyanate dimer (CAS No.: 26747-90-0), and 4,4ˊ,4」-triphenylmethane triisocyanate;

[0030] The amount of 3-methyl-1-phenylphosphazene-1-oxide used is 0.2% to 0.3% of the mass of diisocyanate.

[0031] Furthermore, in S2, the mass ratio of 2-(4-aminophenyl)-5-benzotriazoleamine (CAS No.: 23851-59-4), carbon disulfide, triethylamine, and potassium carbonate is 10:(4.0~4.2):(0.5~0.6):(5.1~5.5).

[0032] The ratio of 2-(4-aminophenyl)-5-benzotriazole amine to deionized water is (15-25) g / 100 mL.

[0033] Furthermore, in S2, the polyethylene glycol is PEG400;

[0034] The mass ratio of thiourea compound, sodium hypochlorite, polyethylene glycol, and sodium hydroxide is 100:(20.3~21.3):(11.4~12.0):(7.6~8.0).

[0035] The ratio of thiourea compound to toluene is (20-25) g / 100 mL;

[0036] Sodium hypochlorite is added in the form of an aqueous solution with a mass concentration of 6% to 8%.

[0037] Sodium hydroxide was added in the form of an aqueous solution with a concentration of 1M.

[0038] Furthermore, in S3, the catalyst is dibutyltin dilaurate;

[0039] The mass ratio of isocyanate-based diimide carbonate, phenyltriazolyl diamine, hydroxyethyl acrylate, and catalyst is 100:(30-40):(1.5-5.0):(0.1-0.3).

[0040] In the above technical solution, the modified ABS component also contains an alkenyl compound, which is obtained by reacting isocyanate-based diimide carbonate, phenyltriazolyl diamine, and hydroxyethyl acrylate. The isocyanate reacts with amino and hydroxyl groups to form a polyurethane structure. Introducing this into the ABS system can effectively improve the processing performance of the polymer material system, enhance its fluidity during injection molding, reduce molding defects, and improve the quality of the matrix. It can also improve the mechanical properties of the polymer material system, making the matrix exhibit better durability, thermal stability, and impact resistance, and a higher pyrolysis temperature. The compatibility between polymer material systems is also improved, and the bonding between the matrix and the metal film (aluminum film) can also be enhanced.

[0041] In the presence of 3-methyl-1-phenylphosphazene-1-oxide, diisocyanate undergoes a condensation reaction to generate carbodiimide, yielding isocyanate-based diimide carbonate. In an aqueous dispersion system, using triethylamine as a catalyst, 2-(4-aminophenyl)-5-benzotriazoleamine reacts with carbon disulfide to form thiourea, yielding a thiourea compound; this compound is then oxidized with sodium hypochlorite in the presence of polyethylene glycol to form carbodiimide, yielding phenyltriazole diamine. Both alkenyl compounds contain carbodiimide in their reaction components, which effectively eliminates carboxyl groups generated during processing, thereby inhibiting the hydrolysis of polymeric materials, reducing the generation of small-molecule volatiles, effectively maintaining the performance of the prepared matrix during production and use, and extending the product's service life.

[0042] Meanwhile, alkenyl compounds made from isocyanate-based diimide carbonate, benzotriazole diamine, and hydroxyethyl acrylate introduce benzotriazole, alicyclic, or aromatic structures into the polymer material system. This improves the mechanical properties, UV resistance, and high-temperature resistance of the matrix, and enhances the bonding with the metal film (aluminum film). Furthermore, it has fewer small molecule products and lower volatiles, which, combined with its high heat resistance, enable it to be primerless, resulting in excellent quality performance of the metal film (aluminum film).

[0043] Furthermore, the injection molding process is as follows: the temperatures of the first to fifth sections of the barrel are 220–230℃, 240–250℃, 240–250℃, 235–245℃, and 225–235℃ respectively; the injection pressures are 45–55MPa, 45–55MPa, 60–70MPa, and 70–80MPa respectively; and the mold entry temperature is 215–225℃.

[0044] Furthermore, before injection molding, the raw material is dried at a temperature of 90–130°C for 2–4 hours.

[0045] Furthermore, before depositing the metal film, the substrate is subjected to plasma treatment to activate the substrate surface. The process conditions are as follows: voltage 1000-1500V, duration 3-5min; discharge gas is one or a mixture of oxygen and argon, gas flow rate 50-300sccm.

[0046] Furthermore, the metal coating is a vacuum evaporation aluminum coating, with the following process conditions: vacuum degree 0.5 × 10⁻⁶. -2 ~5.0×10 -2 Pa, duration 15-30s, voltage 35-50V.

[0047] Furthermore, the upper protective film is formed by plasma deposition of hexamethyldisiloxane, with the following process conditions: vacuum degree 0.5 × 10⁻⁶. -2 ~5.0×10 -2 Pa, duration 6-10 min, voltage 1200-3000 V.

[0048] Furthermore, after applying the protective film, the protective film is subjected to plasma treatment. The specific process conditions are as follows: voltage 1200~1800V, duration 20~50s, discharge gas is oxygen or a mixture of oxygen and argon, and gas flow rate 50~300sccm. Detailed Implementation

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] In the following specific embodiments, the number of "parts" refers to parts by weight;

[0051] ABS: Grade 0215A, sourced from Jilin Petrochemical Co., Ltd.;

[0052] PC: Grade 2805, originating from Bayer AG, Germany;

[0053] PBT: Grade BM434, sourced from Yizheng Chemical Fiber Engineering Plastics, Zhejiang;

[0054] The filler is a mixture of glass fiber and aluminosilicate in a mass ratio of 1:2;

[0055] Glass fiber: Adamas, aspect ratio 6mm / 15μm, sourced from Shanghai Titan Technology Co., Ltd.; Aluminosilicate: surface area 900-1100m² 2 / g, sourced from Shanghai McLean;

[0056] Polyethylene glycol: PEG400, sourced from Nanjing Yingguan New Materials Technology Co., Ltd.;

[0057] The compatibilizer is maleic anhydride-styrene copolymer (SMA) Mn3800, which is sourced from Shanghai Maclean;

[0058] The antioxidants are a mixture of Irganox 245 and Irganox 168 in a mass ratio of 1:1;

[0059] The transesterification inhibitor is a mixture of triphenyl phosphite and sodium hexametaphosphate in a mass ratio of 1:1.

[0060] Example 1: A method for preparing an aging-resistant decorative frame for automotive lights, comprising the following steps:

[0061] Step 1: Preparation of modified ABS:

[0062] S1. Under a nitrogen atmosphere, isophorone diisocyanate and 0.2% 3-methyl-1-phenylphosphazene-1-oxide were mixed, heated to 160°C, and reacted for 10 h to obtain isocyanate-based diimine carbonate.

[0063] S2. 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate were mixed in deionized water and stirred for 100 min; the mixture was heated to 94 °C and refluxed for 12 h; the mixture was cooled, filtered, and dried to obtain thiourea compound; the mass ratio of 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate was 10:4.0:0.5:5.1; the ratio of 2-(4-aminophenyl)-5-benzotriazoleamine to deionized water was 15 g / 100 mL;

[0064] Thiourea compound and polyethylene glycol were mixed in toluene, heated to 68°C, and 8 wt% sodium hypochlorite aqueous solution was added. The mixture was reacted for 90 min. Then, 1 M sodium hydroxide aqueous solution was added, and the mixture was heated to 80°C. The mixture was reacted for 60 min. After washing, rotary evaporation, and crystallization, phenyltriazolyl diamine was obtained. The mass ratio of thiourea compound, sodium hypochlorite, polyethylene glycol, and sodium hydroxide was 100:20.3:11.4:7.6. The ratio of thiourea compound to toluene was 20 g / 100 mL.

[0065] S3. Isocyanate-based diimide carbonate and phenyltriazolyl diamine are mixed, heated to 20°C, and the catalyst dibutyltin dilaurate is added. The mixture is reacted for 30 min. Hydroxyethyl acrylate is then added, and the mixture is heated to 80°C and reacted for 30 min to obtain an alkenyl compound. The mass ratio of isocyanate-based diimide carbonate, phenyltriazolyl diamine, hydroxyethyl acrylate, and catalyst is 100:30:1.5:0.1.

[0066] S4. Mix ABS and initiator, add alkenyl compound and methyl methacrylate, melt extrude, extruder temperature 140-220℃, die head temperature 195℃; dry to obtain modified ABS; modified ABS includes the following components by mass: 100 parts ABS, 4 parts alkenyl compound, 30 parts methyl methacrylate, 0.3 parts initiator dicumyl peroxide;

[0067] Step 2, Injection Molding: Mix 70 parts PC, 30 parts modified ABS, 5 parts PBT, 0.3 parts filler, and 0.2 parts antioxidant, and perform injection molding. The process is as follows: the temperatures of the first to fifth sections of the barrel are 230℃, 250℃, 250℃, 245℃, and 235℃ respectively; the injection pressures are 55MPa, 55MPa, 70MPa, and 80MPa respectively; the mold entry temperature is 225℃ to form the matrix.

[0068] Step 3: Deposit metal film:

[0069] Plasma treatment process: voltage 1000V, duration 3min; discharge gas is oxygen, gas flow rate 50sccm;

[0070] Vacuum evaporation aluminum plating, process conditions are as follows: vacuum degree 0.5 × 10 -2 Pa, duration 30s, voltage 35V, to form a substrate metal film;

[0071] Step 4, Apply protective film: Plasma deposition of hexamethyldisiloxane, process: vacuum degree 0.5 × 10 -2 Pa, duration 10min, voltage 1200V;

[0072] The protective film is subjected to plasma treatment under the following specific conditions: voltage 1200V, duration 50s, discharge gas is oxygen, gas flow rate 50sccm, to form a protective film.

[0073] Example 2: A method for preparing an aging-resistant decorative frame for automotive lights, comprising the following steps:

[0074] Step 1: Preparation of modified ABS:

[0075] S1. Under a nitrogen atmosphere, 4,4-diisocyanate dicyclohexylmethane and 0.25% 3-methyl-1-phenylphosphazene-1-oxide were mixed, heated to 162°C, and reacted for 15 h to obtain isocyanate-based diimine carbonate.

[0076] S2. 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate were mixed in deionized water and stirred for 120 min; the mixture was heated to 95 °C and refluxed for 12 h; the mixture was cooled, filtered, and dried to obtain thiourea compound; the mass ratio of 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate was 10:4.1:0.55:5.3; the ratio of 2-(4-aminophenyl)-5-benzotriazoleamine to deionized water was 20 g / 100 mL;

[0077] Thiourea compound and polyethylene glycol were mixed in toluene, heated to 70°C, and a 7wt% sodium hypochlorite aqueous solution was added. The mixture was reacted for 105 min. A 1M sodium hydroxide aqueous solution was added, and the mixture was heated to 85°C. The mixture was reacted for 75 min. The mixture was washed, rotary evaporated, and crystallized to obtain phenyltriazolyl diamine. The mass ratio of thiourea compound, sodium hypochlorite, polyethylene glycol, and sodium hydroxide was 100:20.8:11.7:7.8. The ratio of thiourea compound to toluene was 22 g / 100 mL.

[0078] S3. Isocyanate-based diimide carbonate and phenyltriazolyl diamine are mixed, heated to 35°C, and the catalyst dibutyltin dilaurate is added. The reaction is carried out for 20 min. Hydroxyethyl acrylate is added, the temperature is raised to 82°C, and the reaction is carried out for 20 min to obtain an alkenyl compound. The mass ratio of isocyanate-based diimide carbonate, phenyltriazolyl diamine, hydroxyethyl acrylate, and catalyst is 100:35:3.3:0.2.

[0079] S4. Mix ABS and initiator, add alkenyl compound and methyl methacrylate, melt extrude, extruder temperature 140-220℃, die head temperature 200℃; dry to obtain modified ABS; modified ABS includes the following mass components: 100 parts ABS, 10 parts alkenyl compound, 24 parts methyl methacrylate, 0.4 parts initiator dicumyl peroxide;

[0080] Step 2, Injection Molding: Mix 60 parts PC, 35 parts modified ABS, 12 parts PBT, 0.6 parts filler, and 1.0 part antioxidant, and then perform injection molding. The process is as follows: the temperatures of the first to fifth sections of the barrel are 225℃, 245℃, 245℃, 240℃, and 230℃ respectively; the injection pressures are 50MPa, 50MPa, 65MPa, and 75MPa respectively; the mold entry temperature is 220℃ to form the matrix.

[0081] Step 3: Deposit metal film:

[0082] The plasma treatment process is as follows: voltage 1200V, duration 4min; discharge gas is a mixture of oxygen and argon, total gas flow rate 150sccm, ratio 1:1.

[0083] Vacuum evaporation aluminum plating, process conditions are as follows: vacuum degree 2.5 × 10 -2 Pa, duration 20s, voltage 45V, to form a substrate metal film;

[0084] Step 4, Apply protective film: Plasma deposition of hexamethyldisiloxane, process: vacuum degree 2.5 × 10⁻⁶ -2 Pa, duration 8min, voltage 2000V;

[0085] The protective film is subjected to plasma treatment under the following specific process conditions: voltage 1500V, duration 35s, discharge gas is a mixture of oxygen and argon, total gas flow rate 150sccm, ratio 1:1, to form a protective film.

[0086] Example 3: A method for preparing an aging-resistant decorative frame for automotive lights, comprising the following steps:

[0087] Step 1: Preparation of modified ABS:

[0088] S1. Under a nitrogen atmosphere, 4,4ˊ,4」-triphenylmethane triisocyanate and 0.3% 3-methyl-1-phenylphosphazene-1-oxide were mixed, heated to 165℃, and reacted for 20 h to obtain isocyanate-based diimine carbonate.

[0089] S2. 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate were mixed in deionized water and stirred for 150 min; the mixture was heated to 98 °C and refluxed for 12 h; the mixture was cooled, filtered, and dried to obtain thiourea compound; the mass ratio of 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate was 10:4.2:0.6:5.5; the ratio of 2-(4-aminophenyl)-5-benzotriazoleamine to deionized water was 25 g / 100 mL;

[0090] Thiourea compound and polyethylene glycol were mixed in toluene, heated to 72°C, and a 6 wt% sodium hypochlorite aqueous solution was added. The mixture was reacted for 120 min. A 1 M sodium hydroxide aqueous solution was added, and the mixture was heated to 90°C. The mixture was then washed, rotary evaporated, and crystallized to obtain phenyltriazolyl diamine. The mass ratio of thiourea compound, sodium hypochlorite, polyethylene glycol, and sodium hydroxide was 100:21.3:12.0:8.0. The ratio of thiourea compound to toluene was 25 g / 100 mL.

[0091] S3. Isocyanate-based diimide carbonate and phenyltriazolyl diamine are mixed, heated to 50°C, and the catalyst dibutyltin dilaurate is added. The reaction is carried out for 10 min. Hydroxyethyl acrylate is added, the temperature is raised to 85°C, and the reaction is carried out for 10 min to obtain an alkenyl compound. The mass ratio of isocyanate-based diimide carbonate, phenyltriazolyl diamine, hydroxyethyl acrylate, and catalyst is 100:40:5.0:0.3.

[0092] S4. Mix ABS and initiator, add alkenyl compound and methyl methacrylate, melt extrude, extruder temperature 140-220℃, die head temperature 205℃; dry to obtain modified ABS; modified ABS includes the following mass components: 100 parts ABS, 15 parts alkenyl compound, 20 parts methyl methacrylate, 0.5 parts initiator dicumyl peroxide;

[0093] Step 2, Injection Molding: Mix 50 parts PC, 40 parts modified ABS, 20 parts PBT, 1.0 part filler, and 2.0 parts antioxidant, and perform injection molding. The process is as follows: the temperatures of the first to fifth sections of the barrel are 220℃, 240℃, 240℃, 235℃, and 225℃ respectively; the injection pressures are 45MPa, 45MPa, 60MPa, and 70MPa respectively; the mold entry temperature is 215℃, forming the matrix.

[0094] Step 3: Deposit metal film:

[0095] The plasma treatment process is as follows: voltage 1500V, duration 5min; discharge gas is a mixture of oxygen and argon, total gas flow rate 300sccm, ratio 1:5;

[0096] Vacuum evaporation aluminum plating, process conditions are as follows: vacuum degree 5.0 × 10 -2 Pa, duration 15s, voltage 50V, to form a substrate metal film;

[0097] Step 4, Apply protective film: Plasma deposition of hexamethyldisiloxane, process: vacuum degree 5.0 × 10 -2 Pa, duration 6min, voltage 3000V;

[0098] The protective film is subjected to plasma treatment under the following specific process conditions: voltage 1800V, duration 20s, discharge gas is a mixture of oxygen and argon, total gas flow rate 300sccm, ratio 1:5, to form a protective film.

[0099] Comparative Example 1: A method for preparing an aging-resistant decorative frame for automotive lights, comprising the following steps:

[0100] Step 1: Preparation of modified ABS:

[0101] Isophorone diisocyanate and 2-(4-aminophenyl)-5-benzotriazoleamine were mixed, heated to 20°C, and dibutyltin dilaurate catalyst was added. The reaction was carried out for 30 min. Hydroxyethyl acrylate was added, and the mixture was heated to 80°C and reacted for 30 min to obtain an alkenyl compound. The mass ratio of isophorone diisocyanate, 2-(4-aminophenyl)-5-benzotriazoleamine, hydroxyethyl acrylate, and catalyst was 10:5.1:5.3:0.01.

[0102] ABS and initiator are mixed, and alkenyl compound and methyl methacrylate are added. The mixture is melt-extruded at an extruder temperature of 140-220°C and a die temperature of 195°C. The mixture is then dried to obtain modified ABS. The modified ABS comprises the following components by mass: 100 parts ABS, 4 parts alkenyl compound, 30 parts methyl methacrylate, and 0.3 parts dicumyl peroxide initiator.

[0103] Steps 2-4 are the same as in Example 1, resulting in a decorative frame.

[0104] Comparative Example 2: A method for preparing an aging-resistant decorative frame for automotive lights, comprising the following steps:

[0105] Step 1: Preparation of modified ABS:

[0106] ABS and initiator are mixed, methyl methacrylate is added, and the mixture is melt-extruded at an extruder temperature of 140-220°C and a die head temperature of 195°C. The mixture is then dried to obtain modified ABS. The modified ABS comprises the following components by weight: 100 parts ABS, 30 parts methyl methacrylate, and 0.3 parts dicumyl peroxide initiator.

[0107] Steps 2-4 are the same as in Example 1, resulting in a decorative frame.

[0108] Comparative Example 3: A method for preparing an aging-resistant decorative frame for automotive lights, comprising the following steps:

[0109] Step 1, Injection Molding: Mix 70 parts PC, 30 parts ABS, 5 parts PBT, 0.3 parts filler, 5 parts compatibilizer, 0.3 parts filler, 0.2 parts antioxidant, and 1 part transesterification inhibitor, and perform injection molding. The process is as follows: the temperatures of the first to fifth sections of the barrel are 230℃, 250℃, 250℃, 245℃, and 235℃ respectively; the injection pressures are 55MPa, 55MPa, 70MPa, and 80MPa respectively; the mold entry temperature is 225℃, forming the matrix.

[0110] Steps 2-3 are the same as steps 3-4 in Example 1, resulting in a decorative frame.

[0111] Experiment: Decorative frames obtained in Examples 1-3 and Comparative Examples 1-3 were used to prepare samples. Their performance was tested and the results were recorded.

[0112] Mechanical properties: The tensile strength of the matrix specimen was tested with reference to GB / T 1040.1 at a tensile rate of 10 mm / min.

[0113] Using ATSM-D256 as the reference standard, the notched impact strength of the matrix specimen was tested, with a notch depth of 2.54 mm and a pendulum weight of 2.8 J.

[0114] Using GB / T 9341 as the reference standard, the bending performance of the matrix specimen was tested at a rate of 2 mm / min.

[0115] Surface gloss: The test sample was injection molded using a gloss meter with a high mirror finish mold having an average centerline roughness of 1.0 nm and a light incident angle of 20°.

[0116] Heat resistance temperature: The heat resistance temperature of the matrix sample was tested with ATSM-D648 as the reference standard. The sample thickness was 6.4 mm and the load was 0.45 MPa.

[0117] UV resistance: The matrix sample was placed in a xenon lamp aging test chamber and aged for 500 hours. Its tensile strength was tested again and its strength loss rate was recorded.

[0118]

[0119] Based on the data in the table above, the following conclusions can be clearly drawn:

[0120] The decorative frames obtained in Examples 1-3 are compared with those obtained in Comparative Examples 1-3. The test results show that...

[0121] Compared to the comparative examples, the decorative frames obtained in Examples 1-3 exhibit higher tensile strength, flexural strength, and impact toughness of the substrate, indicating superior mechanical properties. Their higher surface gloss meets the requirements for primer-free applications, demonstrating excellent processing performance of the substrate injection molding system, strong replication ability of the mold surface, reduced formation of small molecule volatiles, and better surface morphology. Higher heat resistance indicates improved heat resistance of the substrate, less pyrolysis during processing and use, contributing to reduced small molecule volatiles. Lower strength loss rate indicates improved UV resistance of the substrate. This fully demonstrates that the present invention improves the mechanical properties, heat resistance, and UV resistance of the substrate and the resulting decorative frames, achieving primer-free and aging-resistant characteristics.

[0122] Compared to Example 1, the alkenyl compound in Comparative Example 1 was prepared from isophorone diisocyanate, 2-(4-aminophenyl)-5-benzotriazoleamine, and hydroxyethyl acrylate; the modified ABS in Comparative Example 2 was prepared from ABS and methyl methacrylate; the ABS in Comparative Example 3 was unmodified and contained compatibilizers and transesterification inhibitors. The polymer material degraded during processing, leading to an increase in acid value, a decrease in mechanical properties, and intermolecular disruption, accelerating degradation. The matrix's performance continued to decline during storage and use, failing to reach its expected service life. The transesterification inhibitors decomposed small molecules, which is detrimental to the construction of primer-free matrices. The decorative frames obtained in Comparative Examples 1-3 showed deterioration in tensile strength, flexural strength, impact toughness, surface gloss, heat resistance temperature, and strength loss rate. This demonstrates that the matrix composition and process settings in this application can promote a comprehensive improvement in mechanical properties, heat resistance, and UV resistance.

[0123] PBAT is easily degraded during processing, leading to an increase in acid value and melt index, and a decrease in mechanical properties, causing considerable problems for production [6-7]. In addition, in humid and warm environments, the ester bonds in the molecular chain are attacked and damaged by water molecules, resulting in hydrolysis and the production of carboxyl groups. The carboxyl groups further accelerate the hydrolysis process of the ester bonds, which in turn leads to a decrease in the performance of the material during storage and use, and it fails to reach the expected service life.

[0124] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing an aging-resistant decorative frame for automotive lights, characterized in that: The process includes the following steps: Injection molding forms the substrate; metal plating forms the metal film; a protective film is then applied to form the protective film. The matrix comprises the following components by weight: 50-70 parts PC, 30-40 parts ABS, 5-20 parts PBT, 0-10 parts compatibilizer, 0.3-1.0 parts filler, 0.2-2.0 parts antioxidant, and 0-2.0 parts transesterification inhibitor; The ABS was modified, and the specific process is as follows: ABS and initiator were mixed, and alkenyl compound and methyl methacrylate were added. The mixture was melt-extruded at an extruder temperature of 140-220°C and a die head temperature of 195-205°C to obtain modified ABS. The alkenyl compound is prepared by the following process: S1. Under a nitrogen atmosphere, diisocyanate and 3-methyl-1-phenylphosphazene-1-oxide are mixed, heated to 160-165°C, and reacted for 10-20 h to obtain isocyanate-based carbodiimide; S2. Mix 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine and potassium carbonate in deionized water and stir for 100-150 min; heat to 94-98℃ and reflux the reaction solution for 12 h to obtain thiourea compound; Thiourea compound and polyethylene glycol are mixed in toluene, heated to 70-75°C, sodium hypochlorite is added, and the reaction is carried out for 90-120 min; sodium hydroxide is added, the temperature is raised to 80-90°C, and the reaction is carried out for 60-90 min to obtain benzotriazolyldiamine. S3. Mix isocyanate-based carbodiimide and benzotriazolyl diamine, heat to 20-50°C, add catalyst, and react for 10-30 min; add hydroxyethyl acrylate, heat to 80-85°C, and react for 10-30 min to obtain alkenyl compound.

2. The method for preparing an aging-resistant decorative frame for vehicle lights according to claim 1, characterized in that: The modified ABS comprises the following components by weight: 100 parts ABS, 4-15 parts alkenyl compound, 15-30 parts methyl methacrylate, and 0.3-0.5 parts initiator.

3. The method for preparing an aging-resistant decorative frame for vehicle lights according to claim 1, characterized in that: In S1, the diisocyanate is one of cyclohexane-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 4,4-diisocyanate dicyclohexylmethane, dimethylbiphenyl diisocyanate, isophorone diisocyanate, toluene diisocyanate dimer, and 4,4ˊ,4」-triphenylmethane triisocyanate.

4. The method for preparing an aging-resistant decorative frame for vehicle lights according to claim 1, characterized in that: In S2, the mass ratio of 2-(4-aminophenyl)-5-benzotriazoleamine, carbon disulfide, triethylamine, and potassium carbonate is 10:(4.0-4.2):(0.5-0.6):(5.1-5.5).

5. The method for preparing an aging-resistant decorative frame for automotive lights according to claim 1, characterized in that: In S2, the mass ratio of thiourea compound, sodium hypochlorite, polyethylene glycol, and sodium hydroxide is 100:(20.3-21.3):(11.4-12.0):(7.6-8.0).

6. The method for preparing an aging-resistant decorative frame for vehicle lights according to claim 1, characterized in that: In S3, the mass ratio of isocyanate-based carbodiimide, benzotriazolyl diamine, and hydroxyethyl acrylate is 100:(30-40):(1.5-5.0).

7. The method for preparing an aging-resistant decorative frame for vehicle lights according to claim 1, characterized in that: The injection molding process conditions are as follows: the temperatures of the first to fifth sections of the barrel are 220-230℃, 240-250℃, 240-250℃, 235-245℃, and 225-235℃ respectively; the injection pressures are 45-55MPa, 45-55MPa, 60-70MPa, and 70-80MPa respectively; and the mold entry temperature is 215-225℃.

8. The method for preparing an aging-resistant decorative frame for automotive lights according to claim 1, characterized in that: The filler is one or more of carbon fiber, glass fiber, aluminosilicate, barium sulfate, silicon dioxide, and alumina.

9. An aging-resistant decorative frame for vehicle lights prepared by the method according to any one of claims 1-8.

Images