阅读说明：本技术 一种防开裂abs材料及其制品的制备方法 (Anti-cracking ABS material and preparation method of product thereof ) 是由 柏保东 茆正新 周玉艳 董旭 于 2020-12-14 设计创作，主要内容包括：本发明公开了一种防开裂ABS材料及其制品的制备方法。该方法首先将丁二烯进行乳液聚合,得到聚丁二烯胶乳,然后将聚丁二烯胶乳、苯乙烯及丙烯腈进行接枝聚合,得到橡胶接枝共聚物,最后将橡胶接枝共聚物、SAN树脂及抗氧剂进行机械掺混、熔融造粒,得到所述ABS树脂。本发明的方法制备的ABS材料,其聚丁二烯胶乳粒径的可达到500nm以上,使得ABS材料的韧性强,抗冲击强度达到350J/m以上,且耐低温性能增强。利用该ABS树脂制备得到的制品经过退火处理,其抗裂能力得到进一步的提高。(The invention discloses an anti-cracking ABS material and a preparation method of a product thereof. The method comprises the steps of firstly carrying out emulsion polymerization on butadiene to obtain polybutadiene latex, then carrying out graft polymerization on the polybutadiene latex, styrene and acrylonitrile to obtain a rubber graft copolymer, and finally carrying out mechanical blending, melting and granulation on the rubber graft copolymer, SAN resin and an antioxidant to obtain the ABS resin. The particle size of polybutadiene latex of the ABS material prepared by the method can reach more than 500nm, so that the ABS material has strong toughness, the impact strength reaches more than 350J/m, and the low-temperature resistance is enhanced. The product prepared by the ABS resin is annealed, and the crack resistance of the product is further improved.)

1. The preparation method of the anti-cracking ABS material is characterized by comprising the following steps of:

(1) carrying out emulsion polymerization on butadiene, and adding a composite flocculant in the polymerization process to obtain polybutadiene latex;

(2) and (3) carrying out graft polymerization on polybutadiene latex, styrene and acrylonitrile to obtain the rubber graft copolymer.

(3) And mechanically blending the rubber graft copolymer, the SAN resin and the antioxidant, and performing melt granulation to obtain the ABS resin.

2. The preparation method of the anti-cracking ABS material according to claim 1, characterized in that the composite flocculant is ferric sulfate and tartaric acid according to a mass ratio of 1: 1, mixing the mixture.

3. The preparation method of the anti-cracking ABS material as recited in claim 1, wherein the particle size of the polybutadiene latex is controlled to be 500-550 nm.

4. The preparation method of the anti-cracking ABS material as claimed in claim 1, characterized in that the step of emulsion polymerization is: according to the weight portion, 80-100 portions of butadiene, 0.2-0.8 portion of organic hydroperoxide, 5-8 portions of emulsifier, 2-8 portions of composite flocculant and 180 portions of water are uniformly mixed and placed in a water bath kettle with the temperature of 60-70 ℃ for reaction for 10-16 h.

5. The preparation method of the anti-cracking ABS material as claimed in claim 4, characterized in that the organic hydroperoxide is selected from one or more of cumene hydroperoxide, p-isopropyl cumene hydroperoxide and tert-butyl hydroperoxide.

6. The preparation method of the anti-cracking ABS material as recited in claim 4, wherein the emulsifier is selected from one or more of sodium dodecyl sulfate, alkyl alcohol amine, polyoxyethylene abietate diglycerol, and polypropylene glycol ether.

7. The preparation method of the anti-cracking ABS material according to claim 1, characterized in that the step of graft polymerization is: according to the weight portion, 100 portions of polybutadiene latex, 45 to 70 portions of styrene, 25 to 35 portions of acrylonitrile, 0.5 to 2 portions of disproportionated rosin acid soap, 0.4 to 0.8 portion of sodium pyrophosphate, 0.3 to 0.6 portion of glucose, 0.005 to 0.015 portion of ferrous sulfate, 0.8 to 1.2 portions of cumene hydroperoxide, 0.3 to 0.8 portion of tetrahydroxypropylethylenediamine and 450 portions of water of 300 portions are mixed evenly and put into a water bath kettle with the temperature of 60 to 70 ℃ for reaction for 10 to 16 hours.

8. The ABS resin prepared by the preparation method of any one of claims 1-7, wherein the impact strength is 350J/m or more.

9. The method for preparing an ABS product by using the ABS resin of claim 8, comprising the steps of:

(1) adding ABS resin and other raw materials into a high-speed mixer, and blending for 20-30 minutes to obtain a mixture;

(2) adding the obtained mixture into a double-screw extruder, and performing melt extrusion and granulation to obtain granules;

(3) preparing the required ABS product by adopting the granules;

(4) and carrying out annealing treatment on the ABS product.

10. The method according to claim 9, wherein the annealing treatment of the step (4) is to anneal the ABS product at 60 ± 10 ℃ for 2-4 hours, and then slowly cool the product to room temperature.

Technical Field

The invention belongs to the technical field of preparation of anti-cracking resin materials, and particularly relates to an anti-cracking ABS material and a preparation method of an anti-cracking ABS product.

Background

ABS resin is terpolymer of acrylonitrile, butadiene and styrene, and is widely applied to industries such as medical products, automobiles, electronic and electric equipment, instruments and meters, textiles, buildings and the like. The ABS resin is light yellow granular or powdery opaque resin, is nontoxic and tasteless, has relative density of 1.04-1.08, and has excellent impact resistance and low-temperature resistance; the brittle temperature of the ABS resin is-7 ℃, and the thermal deformation temperature is 95-120 ℃; the ABS resin has good chemical resistance, is hardly influenced by dilute acid, dilute alkali and salts, is insoluble in most alcohols such as ethanol and the like, and can swell when being contacted with hydrocarbon solvents for a long time; the ABS resin is subjected to stress cracking when the surface of the ABS resin is soaked by chemical agents such as acetic acid, vegetable oil and the like under the action of stress.

The ABS resin is prepared by mixing a graft copolymer consisting of PB rubber particles of a core phase and SAN of a shell phase with SAN resin, wherein the ABS resin is a two-phase polymer blending system, the continuous phase of the ABS resin is a SAN matrix, and the dispersed phase of the ABS resin is PB rubber particles. When ABS resin is acted by external force, PB rubber particles are used as stress concentration places to induce silver lines in the polymer and induce the matrix to generate shear yield to absorb failure energy. With the continuous development of fracture theory, people put forward a micro-crack theory, a multiple silver grain theory, a shear yield theory, a silver grain shear band theory, a voiding theory, a percolation theory and the like in sequence.

The anti-cracking research on ABS resin is a long-standing subject, and the fundamental measures for anti-cracking are all the measures for increasing the toughness of the material. Patent CN102250443A discloses an ABS flame retardant toughened resin and a preparation method thereof, the ABS flame retardant toughened resin comprises the following raw materials by mass: 100 parts of ABS resin, MgSt 1-3 parts of, Sb₂O₃1 to 5 parts of decabromodiphenylethane, 1 to 15 parts of chlorinated polyethylene, 6 to 12 parts of SBS₂10-10 parts of rubber, 2-5 parts of dispersing agent and 3-5 parts of barium sulfate. The toughening is realized by adding an additive after the ABS resin is synthesized, and the toughening effect is poor. Patent CN103965410B discloses a method for preparing ABS resin by using rare earth integrated rubber as toughening agent in-situ bulk method. The method integrates the work of two units for producing toughened rubber and ABS resin into one unit, directly prepares the toughened rubber in styrene, and further adopts styrene rubber solution to prepare the ABS resinThe resin shortens the production process flow of the ABS resin, omits three working sections of solvent removal, extrusion drying and packaging forming for the post-treatment required by the production of the toughened rubber and two working sections of rubber cutting and rubber dissolving required by ABS resin production units, and greatly improves the production efficiency. However, the method has high preparation cost by adopting rare earth as a raw material, and the improvement is concentrated on the adjustment of the preparation process, so that the preparation process is complex.

Disclosure of Invention

The invention aims to provide an anti-cracking ABS material and a preparation method of a product thereof.

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) carrying out emulsion polymerization on butadiene, and adding a composite flocculant in the polymerization process to obtain polybutadiene latex;

(2) carrying out graft polymerization on polybutadiene latex, styrene and acrylonitrile to obtain a rubber graft copolymer;

(3) and mechanically blending the rubber graft copolymer, the SAN resin and the antioxidant, and performing melt granulation to obtain the ABS resin.

The composite flocculant is a composite flocculant prepared from ferric sulfate and tartaric acid according to a mass ratio of 1: 1, mixing the mixture.

The addition of a flocculating agent to the rubber emulsion may induce the agglomeration of some small particles to produce larger rubber particles. Flocculants relatively large and monodisperse polybutadiene latexes can be synthesized if added in the proper amount during the latex polymerization process.

The particle size of the polybutadiene latex is controlled to be 500-550 nm.

The emulsion polymerization comprises the following steps: according to the weight portion, 80-100 portions of butadiene, 0.2-0.8 portion of organic hydroperoxide, 5-8 portions of emulsifier, 2-8 portions of composite flocculant and 180 portions of water are uniformly mixed and placed in a water bath kettle with the temperature of 60-70 ℃ for reaction for 10-16 h.

The organic hydroperoxide is selected from one or more of cumene hydroperoxide, isopropyl cumene hydroperoxide and tert-butyl hydroperoxide.

The emulsifier is one or more selected from sodium dodecyl sulfate, alkyl alcohol amine, polyoxyethylene abietate diglycerol and polypropylene glycol ether.

The graft polymerization comprises the following steps: according to the weight portion, 100 portions of polybutadiene latex, 45 to 70 portions of styrene, 25 to 35 portions of acrylonitrile, 0.5 to 2 portions of disproportionated rosin acid soap, 0.4 to 0.8 portion of sodium pyrophosphate, 0.3 to 0.6 portion of glucose, 0.005 to 0.015 portion of ferrous sulfate, 0.8 to 1.2 portions of cumene hydroperoxide, 0.3 to 0.8 portion of tetrahydroxypropylethylenediamine and 450 portions of water of 300 portions are mixed evenly and put into a water bath kettle with the temperature of 60 to 70 ℃ for reaction for 10 to 16 hours.

The invention also aims to provide the ABS resin prepared by the method, and the impact strength of the ABS resin reaches more than 350J/m.

The invention also aims to provide a method for preparing an ABS product by adopting the material, which comprises the following steps:

(1) adding ABS resin and other raw materials into a high-speed mixer, and blending for 20-30 minutes to obtain a mixture;

(2) adding the obtained mixture into a double-screw extruder, and performing melt extrusion and granulation to obtain granules;

(3) preparing the required ABS product by adopting the granules;

(4) and carrying out annealing treatment on the ABS product.

And (4) annealing the ABS product at 60 +/-10 ℃ for 2-4 hours, and then slowly cooling to room temperature.

The invention has the beneficial effects that: the particle size of polybutadiene latex of the ABS material prepared by the method can reach more than 500nm, so that the ABS material has strong toughness, the impact strength reaches more than 350J/m, and the low-temperature resistance is enhanced. Meanwhile, the prepared ABS product is annealed, so that the internal stress is eliminated, the product is prevented from cracking, the stability of the product is improved, and the service life of the product is prolonged.

Detailed Description

The present invention is further illustrated by the following specific examples.

Example 1

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 90 parts of butadiene, 0.5 part of cumene hydroperoxide, 6 parts of sodium dodecyl sulfate, 2 parts of ferric sulfate, 2 parts of tartaric acid and 150 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 65 ℃ and reacted for 12 hours to obtain polybutadiene latex;

(2) according to the weight portion, 110 portions of polybutadiene latex, 60 portions of styrene, 30 portions of acrylonitrile, 1 portion of disproportionated rosin acid soap, 0.6 portion of sodium pyrophosphate, 0.5 portion of glucose, 0.01 portion of ferrous sulfate, 1 portion of cumene hydroperoxide, 0.6 portion of tetrahydroxypropyl ethylenediamine and 400 portions of water are uniformly mixed and placed in a water bath kettle with the temperature of 65 ℃ for reaction for 12 hours, and the rubber graft copolymer is obtained.

(3) 100 parts of SAN resin, 5 parts of tris (2, 4-di-tert-butyl) phenyl phosphite and 25 parts of rubber graft copolymer are weighed, fully mixed to be uniformly dispersed, and melt blending is carried out in a double-screw extruder at 220 ℃ to obtain ABS resin granules.

The ABS resin particles can be prepared into corresponding ABS products according to a conventional process method. In this example, the prepared article was further annealed at 55 ℃ for 3 hours.

Example 2

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 88 parts of butadiene, 0.3 part of isopropyl cumene hydroperoxide, 6 parts of alkyl alcohol amine, 1 part of ferric sulfate, 1 part of tartaric acid and 120 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 62 ℃ and reacted for 15 hours to obtain polybutadiene latex;

(2) according to the weight parts, 100 parts of polybutadiene latex, 50 parts of styrene, 25 parts of acrylonitrile, 0.8 part of disproportionated rosin acid soap, 0.5 part of sodium pyrophosphate, 0.4 part of glucose, 0.008 part of ferrous sulfate, 0.8 part of cumene hydroperoxide, 0.3 part of tetrahydroxypropylethylenediamine and 320 parts of water are uniformly mixed, and the mixture is placed in a water bath kettle at the temperature of 62 ℃ for reaction for 15 hours to obtain a rubber graft copolymer;

(3) weighing 80 parts of SAN resin, 2 parts of 2, 6-tertiary butyl-4-methylphenol and 20 parts of rubber graft copolymer, fully mixing to uniformly disperse the SAN resin, and carrying out melt blending in a double-screw extruder at 200 ℃ to obtain ABS resin granules.

The ABS resin particles can be prepared into corresponding ABS products according to a conventional process method.

Example 3

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 95 parts of butadiene, 0.7 part of tert-butyl hydroperoxide, 8 parts of rosin acid polyoxyethylene ester diglycerol, 3 parts of ferric sulfate, 3 parts of tartaric acid and 170 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 70 ℃ and reacted for 11 hours to obtain polybutadiene latex;

(2) according to the weight portion, 120 portions of polybutadiene latex, 65 portions of styrene, 35 portions of acrylonitrile, 1.5 portions of disproportionated rosin acid soap, 0.7 portion of sodium pyrophosphate, 0.6 portion of glucose, 0.012 portion of ferrous sulfate, 1 portion of cumene hydroperoxide, 0.7 portion of tetrahydroxypropyl ethylenediamine and 420 portions of water are uniformly mixed and put in a water bath kettle with the temperature of 68 ℃ for reaction for 14 hours, thus obtaining the rubber graft copolymer.

(3) 100 parts of SAN resin, 3.5 parts of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester and 35 parts of rubber graft copolymer are weighed, fully mixed to be uniformly dispersed, and melt blending is carried out in a double-screw extruder at 180 ℃ to obtain ABS resin granules.

The ABS resin particles can be prepared into corresponding ABS products according to a conventional process method.

Example 4

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 90 parts of butadiene, 0.2 part of isopropyl cumene hydroperoxide, 8 parts of polypropylene glycol ether, 2 parts of ferric sulfate, 2 parts of tartaric acid and 130 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 62 ℃ and reacted for 12 hours to obtain polybutadiene latex;

(2) according to the weight parts, taking 110 parts of polybutadiene latex, 48 parts of styrene, 32 parts of acrylonitrile, 1.4 parts of disproportionated rosin acid soap, 0.6 part of sodium pyrophosphate, 0.6 part of glucose, 0.011 part of ferrous sulfate, 0.9 part of cumene hydroperoxide, 0.3 part of tetrahydroxypropylethylenediamine and 330 parts of water, uniformly mixing, placing in a water bath kettle at the temperature of 62 ℃, and reacting for 12 hours to obtain a rubber graft copolymer;

(3) weighing 150 parts of SAN resin, 5 parts of antioxidant tris (2, 4-di-tert-butyl) phenyl phosphite and 42 parts of rubber graft copolymer, fully mixing to uniformly disperse the components, and carrying out melt blending in a double-screw extruder at 210 ℃ to obtain ABS resin granules.

The ABS resin particles can be prepared into corresponding ABS products according to a conventional process method. In this example, the prepared article was further annealed at 60 ℃ for 3 hours.

Example 5

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 85 parts of butadiene, 0.7 part of cumene hydroperoxide, 5 parts of polypropylene glycol ether, 2 parts of ferric sulfate, 2 parts of tartaric acid and 150 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 68 ℃ and reacted for 13 hours to obtain polybutadiene latex;

(2) according to the weight parts, 100 parts of polybutadiene latex, 45 parts of styrene, 25 parts of acrylonitrile, 0.6 part of disproportionated rosin acid soap, 0.6 part of sodium pyrophosphate, 0.5 part of glucose, 0.008 part of ferrous sulfate, 0.9 part of cumene hydroperoxide, 0.6 part of tetrahydroxypropylethylenediamine and 380 parts of water are uniformly mixed, and the mixture is placed in a water bath kettle at the temperature of 67 ℃ to react for 14 hours to obtain a rubber graft copolymer;

(3) weighing 120 parts of SAN resin, 4.8 parts of antioxidant tri (2, 4-di-tert-butyl) phenyl phosphite and 38 parts of rubber graft copolymer, fully mixing to uniformly disperse the components, and carrying out melt blending in a double-screw extruder at 230 ℃ to obtain ABS resin granules.

The ABS resin particles can be prepared into corresponding ABS products according to a conventional process method.

Comparative example 1

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 90 parts of butadiene, 0.5 part of cumene hydroperoxide, 6 parts of sodium dodecyl sulfate, 2 parts of ferric sulfate and 150 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 65 ℃ and reacted for 12 hours to obtain polybutadiene latex;

(2) according to the weight portion, 110 portions of polybutadiene latex, 60 portions of styrene, 30 portions of acrylonitrile, 1 portion of disproportionated rosin acid soap, 0.6 portion of sodium pyrophosphate, 0.5 portion of glucose, 0.01 portion of ferrous sulfate, 1 portion of cumene hydroperoxide, 0.6 portion of tetrahydroxypropyl ethylenediamine and 400 portions of water are uniformly mixed and placed in a water bath kettle with the temperature of 65 ℃ for reaction for 12 hours, and the rubber graft copolymer is obtained.

(3) 100 parts of SAN resin, 5 parts of tris (2, 4-di-tert-butyl) phenyl phosphite and 25 parts of rubber graft copolymer are weighed, fully mixed to be uniformly dispersed, and melt blending is carried out in a double-screw extruder at 220 ℃ to obtain ABS resin granules.

Comparative example 2

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 90 parts of butadiene, 0.5 part of cumene hydroperoxide, 6 parts of sodium dodecyl sulfate, 2 parts of tartaric acid and 150 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 65 ℃ and reacted for 12 hours to obtain polybutadiene latex;

(2) according to the weight portion, 110 portions of polybutadiene latex, 60 portions of styrene, 30 portions of acrylonitrile, 1 portion of disproportionated rosin acid soap, 0.6 portion of sodium pyrophosphate, 0.5 portion of glucose, 0.01 portion of ferrous sulfate, 1 portion of cumene hydroperoxide, 0.6 portion of tetrahydroxypropyl ethylenediamine and 400 portions of water are uniformly mixed and placed in a water bath kettle with the temperature of 65 ℃ for reaction for 12 hours, and the rubber graft copolymer is obtained.

(3) 100 parts of SAN resin, 5 parts of tris (2, 4-di-tert-butyl) phenyl phosphite and 25 parts of rubber graft copolymer are weighed, fully mixed to be uniformly dispersed, and melt blending is carried out in a double-screw extruder at 220 ℃ to obtain ABS resin granules.

Comparative example 3

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight portion, 90 portions of butadiene, 0.5 portion of cumene hydroperoxide, 6 portions of sodium dodecyl sulfate and 150 portions of water are uniformly mixed, and the mixture is placed in a water bath kettle with the temperature of 65 ℃ to react for 12 hours to obtain polybutadiene latex;

(2) according to the weight portion, 110 portions of polybutadiene latex, 60 portions of styrene, 30 portions of acrylonitrile, 1 portion of disproportionated rosin acid soap, 0.6 portion of sodium pyrophosphate, 0.5 portion of glucose, 0.01 portion of ferrous sulfate, 1 portion of cumene hydroperoxide, 0.6 portion of tetrahydroxypropyl ethylenediamine and 400 portions of water are uniformly mixed and placed in a water bath kettle with the temperature of 65 ℃ for reaction for 12 hours, and the rubber graft copolymer is obtained.

(3) 100 parts of SAN resin, 5 parts of tris (2, 4-di-tert-butyl) phenyl phosphite and 25 parts of rubber graft copolymer are weighed, fully mixed to be uniformly dispersed, and melt blending is carried out in a double-screw extruder at 220 ℃ to obtain ABS resin granules.

Comparative example 4

A preparation method of an anti-cracking ABS material comprises the following steps:

(1) according to the weight parts, 90 parts of butadiene, 0.5 part of cumene hydroperoxide, 6 parts of sodium dodecyl sulfate, 2 parts of ferric sulfate, 2 parts of tartaric acid and 150 parts of water are uniformly mixed, placed in a water bath kettle at the temperature of 65 ℃ and reacted for 12 hours to obtain polybutadiene latex;

(2) according to the weight portion, 110 portions of polybutadiene latex, 60 portions of styrene, 30 portions of acrylonitrile, 1 portion of disproportionated rosin acid soap, 0.6 portion of sodium pyrophosphate, 0.5 portion of glucose, 0.01 portion of ferrous sulfate, 1 portion of cumene hydroperoxide and 400 portions of water are uniformly mixed and placed in a water bath kettle with the temperature of 65 ℃ for reaction for 12 hours, and the rubber graft copolymer is obtained.

(3) 100 parts of SAN resin, 5 parts of tris (2, 4-di-tert-butyl) phenyl phosphite and 25 parts of rubber graft copolymer are weighed, fully mixed to be uniformly dispersed, and melt blending is carried out in a double-screw extruder at 220 ℃ to obtain ABS resin granules.

Experimental example 1:

the polybutadiene latices prepared in the steps (1) of examples 1 to 5 and comparative examples 1 to 3 were respectively measured for particle size using a laser particle size meter of type BI-90Plus based on Brownian movement of particles in a suspending liquid, charged particles were fluctuated in an electromagnetic field formed by light waves under laser light, fluctuation variation caused light scattering, and the particle size in the suspension was measured by measuring the number of attenuation times of the waves over a certain period of time because the number of attenuation times of the waves was related to the particle size, and the results of the measurement are shown in Table 1:

TABLE 1

Note: represents P < 0.05; represents P < 0.01.

As can be seen from Table 1, the addition of the flocculant can significantly increase the particle size of the polybutadiene latex, and the composite flocculant has a significant synergistic effect compared with a single agent.

Experimental example 2:

the ABS resin pellets prepared in examples 1-5 and comparative examples 1-4 were used to prepare test samples at 200 ℃ on an injection molding machine, wherein examples 1 and 4 were annealed at 55 ℃ and 60 ℃ for 3 hours, respectively, and the products obtained in comparative examples 1-4 were subjected to no annealing treatment, and the Izod impact strength value of the ABS resin was measured according to ASTM D256, and the tensile strength was measured according to ASTM D638-01, with the test results shown in Table 2:

TABLE 2

Note: represents P < 0.05; represents P < 0.01.

As can be seen from Table 2, the addition of the flocculant increases the particle size of the polybutadiene latex significantly, and finally the impact strength and tensile strength of the prepared ABS resin are enhanced, and the ABS resin is resistant to cracking. Meanwhile, the internal stress of the product is further eliminated through annealing process treatment, and the crack resistance of the product is improved.