阅读说明：本技术 一种半芳香族聚酰胺树脂及其制备方法与应用 (Semi-aromatic polyamide resin and preparation method and application thereof ) 是由 李克和 洪江 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种半芳香族聚酰胺树脂,属于化工领域。本发明所述半芳香族聚酰胺树脂通过在组分中添加特定比例的芳香胺化合物、含磷化合物和含硫化合物,这些组分作为耐热稳定剂和增白剂可显著提高所得产品的初始白度和耐热氧老化稳定性。本发明还公开了所述半芳香族聚酰胺树脂的制备方法,所述制备方法操作步骤简单,可实现工业化大规模生产。本发明还公开了由所述半芳香族聚酰胺树脂制备的模塑组合物,该产品同样具有高初始白度和良好的耐热防老黄化性能。(The invention discloses a semi-aromatic polyamide resin, belonging to the field of chemical industry. The semi-aromatic polyamide resin provided by the invention can remarkably improve the initial whiteness and the stability against thermal oxidative aging of the obtained product by adding the aromatic amine compound, the phosphorus-containing compound and the sulfur-containing compound in specific proportions into the components serving as the heat-resistant stabilizer and the whitening agent. The invention also discloses a preparation method of the semi-aromatic polyamide resin, which has simple operation steps and can realize industrial large-scale production. The invention also discloses a molding composition prepared from the semi-aromatic polyamide resin, and the product also has high initial whiteness and good heat-resistant anti-yellowing performance.)

1. A semi-aromatic polyamide resin characterized by comprising, in mole percent, the following components of recurring units: diamine monomers and diacid monomers; the diamine monomer comprises decamethylene diamine and the diacid monomer comprises aromatic diacid; the component also comprises aromatic amine compound, phosphorus-containing compound and sulfur-containing compound.

2. The semi-aromatic polyamide resin according to claim 1, wherein the aromatic amine compound, the phosphorus-containing compound and the sulfur-containing compound are present in a mass ratio of: aromatic amine compound: phosphorus-containing compounds: 1-6% of a sulfur-containing compound: 1-6: 1 to 1.5; the total mass content of the aromatic amine compound, the phosphorus-containing compound and the sulfur-containing compound in the semi-aromatic polyamide resin component is 0.2-3%.

3. The semi-aromatic polyamide resin of claim 1, wherein the diamine monomer further comprises hexamethylene diamine, the diacid monomer further comprises adipic acid; preferably, each mole of diamine monomer comprises 0.5-1 mole of decamethylenediamine and 0-0.5 mole of hexanediamine, each mole of diacid monomer comprises 0.5-1 mole of aromatic diacid and 0-0.5 mole of adipic acid, and the aromatic diacid comprises terephthalic acid and isophthalic acid.

4. The semi-aromatic polyamide resin according to claim 1, wherein the semi-aromatic polyamide resin contains 10 to 1000ppm by mass of phosphorus and 1 to 500ppm by mass of sulfur; preferably, the semi-aromatic polyamide resin contains 20-600 ppm of phosphorus and 2-200 ppm of sulfur by mass; preferably, the semi-aromatic polyamide resin contains 30 to 500ppm by mass of phosphorus and 3 to 50ppm by mass of sulfur.

5. The semi-aromatic polyamide resin according to claim 1, wherein the aromatic amine compound is an amine compound containing an imino group; preferably, the aromatic amine compound includes 4- (phenylacetyloxy) -2,2,6, 6-tetramethylpiperidine, 4-benzoyloxy-2, 2,6, 6-tetramethylpiperidine, 4-cyclohexyloxy-2, 2,6, 6-tetramethylpiperidine, 4-benzyloxy-2, 2,6, 6-tetramethylpiperidine, 4-phenoxy-2, 2,6, 6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6, 6-tetramethylpiperidine, bis (2,2,6, 6-tetramethyl-4-piperidyl) terephthalate, α' -bis (2,2,6, 6-tetramethyl-4-piperidinyloxy) p-xylene, bis (2,2,6, 6-tetramethyl-4-piperidyl) -toluene-2, 4-dicarbamate, tris (2,2,6, 6-tetramethyl-4-piperidyl) -benzene-1, 3, 5-tricarboxylate, tris (2,2,6, 6-tetramethyl-4-piperidyl) -benzene-1, 3, 4-tricarboxylate, 1- [2- {3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyloxy } butyl ] -4- [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyloxy ] -2,2,6, 6-tetramethylpiperidine, 4 '-bis (alpha, alpha' -dimethylbenzyl) diphenylamine.

6. The semi-aromatic polyamide resin according to claim 1, wherein the phosphorus-containing compound comprises at least one of an inorganic phosphorus-containing compound and an organic phosphorus-containing compound; the inorganic phosphorus-containing compound comprises at least one of an inorganic phosphoric acid compound, an inorganic phosphorous acid compound, an inorganic hypophosphorous acid compound, a metal phosphate compound, a metal phosphite compound and a metal hypophosphite compound; the organic phosphorus-containing compound includes trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, diphenyloctyl phosphite, triisodecyl phosphite, diisodecyl monobenzene phosphite, ditridecyl phosphite, diisooctyl diphenyl phosphite, diisodecyl diphenyl phosphite, ditridecyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2, 4-di-t-butylphenyl) phosphite, 2, 6-di-t-butyl-4-methylphenyl pentaerythritol diphosphite, 2, 6-di-t-butyl-4-methylphenyl methyl pentaerythritol diphosphite, bis (2, 6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2, 6-di-t-butyl-4-ethylphenyl) pentaerythritol diphosphite, diphenyl-ethyl phosphite, At least one of bis (2, 6-di-tert-amyl-4-methylphenyl) pentaerythritol diphosphite and bis (2, 6-di-tert-octyl-4-methylphenyl) pentaerythritol diphosphite.

7. The semi-aromatic polyamide resin according to claim 1, wherein the sulfur compound includes at least one of an organic sulfur compound and an inorganic sulfur compound; the inorganic sulfur-containing compound comprises at least one of inorganic sulfide, inorganic sulfuric acid compounds, inorganic sulfite compounds, sulfide salt compounds, sulfate salt compounds and sulfite compounds; the organic sulfur-containing compound includes at least one of pentaerythritol tetrakis (3-laurylthiopropionate), dilauryl 3,3 ' -thiodipropionate, dimyristyl 3,3 ' -thiodipropionate, distearyl 3,3 ' -thiodipropionate, distearylthiodipropionate and biscinnamoylthiodipropionate.

8. The method for producing a semi-aromatic polyamide resin according to any one of claims 1 to 7, characterized in that the method comprises: adding a catalyst and an end-capping reagent into a diamine monomer and a diacid monomer, uniformly mixing, adding an aromatic amine compound, a phosphorus-containing compound and a sulfur-containing compound, and carrying out polymerization reaction to obtain the semi-aromatic polyamide resin.

9. A molding composition prepared from the semi-aromatic polyamide resin of any one of claims 1 to 7, characterized by comprising the following components in mass content: 40 to 90% of the semi-aromatic polyamide resin according to any one of claims 1 to 7, and 10 to 60% of a functional filler; the functional filler comprises at least one of a white pigment and a reinforcing filler.

10. The molding composition of claim 9, wherein said white pigment comprises at least one of titanium dioxide, zinc sulfide, zinc oxide, white lead, barium sulfate, zinc sulfate, calcium carbonate, aluminum oxide; the reinforcing filler comprises at least one of fibrous reinforcing filler, tabular reinforcing filler and needle-shaped reinforcing filler; more preferably, the fibrous reinforcing filler comprises at least one of glass fibers, carbon fibers, aramid fibers, metal fibers; the flat plate-shaped reinforcing fiber comprises at least one of mica and talcum powder; the needle-shaped reinforcing filler comprises at least one of potassium titanate whisker, wollastonite, aluminum borate whisker, xonotlite, calcium carbonate whisker, sepiolite and zinc oxide whisker; the reinforcing filler also comprises at least one of silicon dioxide, aluminum nitride, aluminum oxide, barium carbonate, boron nitride, potassium titanate, kaolin, attapulgite, clay, pyrophyllite, carbon nano tubes, bentonite, calcium silicate, aluminum borate, barium sulfate, asbestos, glass beads, graphite, silicon carbide, sericite, calcium sulfate, hydrotalcite and molybdenum disulfide.

Technical Field

The invention relates to the field of chemical industry, and particularly relates to a semi-aromatic polyamide resin, and a preparation method and application thereof.

Background

The polyamide has the characteristics of good comprehensive properties including excellent mechanical property, wear resistance, heat resistance, chemical resistance, self-lubricity, low friction coefficient, easiness in processing and the like, and is widely applied to the fields of plastic products such as glass fiber, mineral filling, flame retardant modification and the like. Over the last 10 years, semi-aromatic polyamides have been gaining increasing attention due to their outstanding heat resistance and excellent mechanical properties.

The semi-aromatic polyamide is widely applied to the field of electronic and electric appliances, has outstanding heat resistance, is widely used for manufacturing a reflecting support of an LED in the field of Light Emitting Diodes (LEDs), particularly PA10T and derivatives thereof, and has higher melting point and heat resistance stability, so that the effect of the semi-aromatic polyamide as the reflecting support of the LED is better than that of other types of semi-aromatic polyamides such as PA4T, PA6T and the like.

When the semi-aromatic polyamide is applied to an LED, the semi-aromatic polyamide is required to have good light-tight property and excellent light reflection property; meanwhile, in the use process of the LED product, the LED product can be exposed to light and high-temperature environment, so that yellowing is easily caused to affect the reflection effect of the LED product on the light. In addition, in the preparation process of the LED, the LED workpiece needs to be heated to about 180 ℃ and maintained for 1-2 hours so as to cure the epoxy resin or the silica gel encapsulant; when the lead-free soldering tin surface mounting is carried out, the LED workpiece is exposed to the peak temperature higher than 265 ℃ in a reflow soldering furnace and is maintained for 2-4 min; furthermore, in use, such as when the LED article is used in an automotive lighting fixture, it is subjected to ambient temperatures greater than 120 ℃ generated by the LED chip for an extended period of time.

When the LED reflecting bracket is exposed to light and heat in application, semi-aromatic polyamide used as the material of the LED reflecting bracket is easy to undergo thermo-oxidative aging and photo-aging, the whiteness and the reflectivity of the material are rapidly reduced, and the phenomena of yellowing, cracking and even pulverization are caused.

Under the circumstances, in the prior art, when a semi-aromatic polyamide composition applied to an LED reflection support material is prepared, titanium dioxide is often added as a filler, so that the whiteness of the material can be improved, and the titanium dioxide also has excellent light reflection performance. However, the root cause of the phenomena of yellowing, embrittlement, pulverization and the like of the LED reflecting bracket material after long-term thermal-oxidative aging and light aging is the aging of the semi-aromatic polyamide resin matrix. In the prior art, the common method for improving aging is to add an antioxidant, a light stabilizer and other auxiliaries when a double-screw extruder is used for preparing the polyamide composition, so that the aging of the polyamide composition is favorably delayed, and the aging resistance of the material is improved.

However, the above method cannot improve the initial whiteness of the material at the source and solve various aging problems of the material after long-term thermo-oxidative aging and photo-aging. The reason is that, when a semi-aromatic polyamide resin is selected, the effect is not significant regardless of the addition of an antioxidant, a light-reflecting filler or a light stabilizer at the later stage in the preparation of the composition, i.e., the initial whiteness and the aging resistance of the semi-aromatic polyamide resin itself substantially determine the whiteness and the aging resistance of the final composition.

Disclosure of Invention

Based on the defects of the prior art, the invention aims to provide a semi-aromatic polyamide resin with high initial whiteness and excellent thermal-oxidative aging resistance, which can improve the whiteness and the aging resistance of the semi-aromatic polyamide resin from the source without adding other additional auxiliary agents during processing and use.

In order to achieve the purpose, the invention adopts the technical scheme that:

a semi-aromatic polyamide resin comprises the following components of a repeating unit in percentage by mol: diamine monomers and diacid monomers; the diamine monomer comprises decamethylene diamine and the diacid monomer comprises aromatic diacid; the component also comprises aromatic amine compound, phosphorus-containing compound and sulfur-containing compound.

Preferably, the aromatic amine compound, the phosphorus-containing compound and the sulfur-containing compound are in a mass ratio of: aromatic amine compound: phosphorus-containing compounds: 1-6% of a sulfur-containing compound: 1-6: 1 to 1.5.

After a great deal of experiments, the inventor finds that when an aromatic compound, a phosphorus-containing compound and a sulfur-containing compound are added into a raw material for preparing the semi-aromatic polyamide resin, and the addition amounts of the three substances are in specific proportions, the initial whiteness and the thermo-oxidative aging resistance stability of the obtained semi-aromatic polyamide resin product are obviously improved.

The semi-aromatic polyamide resin provided by the invention can obviously improve the initial whiteness and the stability against thermal oxidation aging of the obtained product by adding the aromatic amine compound, the phosphorus-containing compound and the sulfur-containing compound in specific proportions into the components which are used as the heat-resistant stabilizer and the whitening agent.

Preferably, the diamine monomer further comprises hexamethylenediamine, the diacid monomer further comprises adipic acid; more preferably, the diamine monomer comprises 0.5-1 mol of decamethylenediamine and 0-0.5 mol of hexanediamine per mol of diamine monomer, and the diacid monomer comprises 0.5-1 mol of aromatic diacid and 0-0.5 mol of hexanedioic acid per mol of diacid monomer.

The diamine monomer and the diacid monomer in the proportion can effectively carry out polymerization reaction, and the obtained polyamide resin product has high purity.

Preferably, the aromatic amine compound, the phosphorus-containing compound and the sulfur-containing compound are contained in the semi-aromatic polyamide resin component in a total amount of 0.2 to 3% by mass.

More preferably, the aromatic amine compound, the phosphorus-containing compound and the sulfur-containing compound are contained in the semi-aromatic polyamide resin component in a total amount of 0.6 to 1.5% by mass.

The additive with the content can effectively improve the initial whiteness and the stability of resisting thermal oxidation aging of the product, and meanwhile, the functional properties of the product, such as viscosity, strength and the like, cannot be influenced.

Preferably, the semi-aromatic polyamide resin contains 10 to 1000ppm by mass of phosphorus and 1 to 500ppm by mass of sulfur. More preferably, the semi-aromatic polyamide resin contains 20 to 600ppm by mass of phosphorus and 2 to 200ppm by mass of sulfur; more preferably, the semi-aromatic polyamide resin contains 30 to 500ppm by mass of phosphorus and 3 to 50ppm by mass of sulfur.

The phosphorus-containing compound and the sulfur-containing compound added under the condition can effectively improve the crosslinking degree of the product and improve the mechanical strength of the resin product to a certain extent.

Preferably, the aromatic diacids include terephthalic acid and isophthalic acid.

Preferably, the aromatic amine compound is an amine compound containing an imino group; more preferably, the aromatic amine compound includes 4- (phenylacetyloxy) -2,2,6, 6-tetramethylpiperidine, 4-benzoyloxy-2, 2,6, 6-tetramethylpiperidine, 4-cyclohexyloxy-2, 2,6, 6-tetramethylpiperidine, 4-benzyloxy-2, 2,6, 6-tetramethylpiperidine, 4-phenoxy-2, 2,6, 6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6, 6-tetramethylpiperidine, bis (2,2,6, 6-tetramethyl-4-piperidyl) terephthalate, α' -bis (2,2,6, 6-tetramethyl-4-piperidinyloxy) p-xylene, bis (2,2,6, 6-tetramethyl-4-piperidyl) -toluene-2, 4-dicarbamate, tris (2,2,6, 6-tetramethyl-4-piperidyl) -benzene-1, 3, 5-tricarboxylate, tris (2,2,6, 6-tetramethyl-4-piperidyl) -benzene-1, 3, 4-tricarboxylate, 1- [2- {3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyloxy } butyl ] -4- [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyloxy ] -2,2,6, 6-tetramethylpiperidine, 4 '-bis (alpha, alpha' -dimethylbenzyl) diphenylamine.

Preferably, the phosphorus-containing compound comprises at least one of an inorganic phosphorus-containing compound and an organic phosphorus-containing compound; the inorganic phosphorus-containing compound comprises at least one of an inorganic phosphoric acid compound, an inorganic phosphorous acid compound, an inorganic hypophosphorous acid compound, a metal phosphate compound, a metal phosphite compound and a metal hypophosphite compound; the organic phosphorus-containing compound includes trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, diphenyloctyl phosphite, triisodecyl phosphite, diisodecyl monobenzene phosphite, ditridecyl phosphite, diisooctyl diphenyl phosphite, diisodecyl diphenyl phosphite, ditridecyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2, 4-di-t-butylphenyl) phosphite, 2, 6-di-t-butyl-4-methylphenyl pentaerythritol diphosphite, 2, 6-di-t-butyl-4-methylphenyl methyl pentaerythritol diphosphite, bis (2, 6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2, 6-di-t-butyl-4-ethylphenyl) pentaerythritol diphosphite, diphenyl-ethyl phosphite, At least one of bis (2, 6-di-tert-amyl-4-methylphenyl) pentaerythritol diphosphite and bis (2, 6-di-tert-octyl-4-methylphenyl) pentaerythritol diphosphite.

Preferably, the sulfur-containing compound comprises at least one of an organic sulfur-containing compound and an inorganic sulfur-containing compound; the inorganic sulfur-containing compound comprises at least one of inorganic sulfide, inorganic sulfuric acid compounds, inorganic sulfite compounds, sulfide salt compounds, sulfate salt compounds and sulfite compounds; the organic sulfur-containing compound includes at least one of pentaerythritol tetrakis (3-laurylthiopropionate), dilauryl 3,3 ' -thiodipropionate, dimyristyl 3,3 ' -thiodipropionate, distearyl 3,3 ' -thiodipropionate, distearylthiodipropionate and biscinnamoylthiodipropionate.

Another object of the present invention is to provide a method for preparing the semi-aromatic polyamide resin, the method comprising: adding a catalyst and an end-capping reagent into a diamine monomer and a diacid monomer, uniformly mixing, adding an aromatic amine compound, a phosphorus-containing compound and a sulfur-containing compound, and carrying out polymerization reaction to obtain the semi-aromatic polyamide resin.

The preparation method provided by the invention is simple in operation steps, and can realize industrial large-scale production.

Preferably, the semi-aromatic polyamide resin obtained by the preparation method has a concentration of 10mg/mL in 98% concentrated sulfuric acid at 25 ℃ and a relative viscosity of 1.8-2.7, preferably 1.9-2.4; the melting point is 280-340 ℃, preferably 295-325 ℃.

It is a further object of the present invention to provide a molding composition prepared from the semi-aromatic polyamide resin of the present invention, comprising the following components in mass content: 40-90% of semi-aromatic polyamide resin and 10-60% of functional filler; the functional filler comprises at least one of a white pigment and a reinforcing filler.

Based on the high initial whiteness and the thermal oxidation aging resistance stability of the semi-aromatic polyamide resin provided by the invention, the whiteness or the mechanical property of a product can be further improved by mixing the semi-aromatic polyamide resin with a functional filler, so that the semi-aromatic polyamide resin is applied to a plurality of fields.

Preferably, the white pigment includes at least one of titanium dioxide, zinc sulfide, zinc oxide, white lead, barium sulfate, zinc sulfate, calcium carbonate, and aluminum oxide.

Preferably, the reinforcing filler comprises at least one of fibrous reinforcing filler, tabular reinforcing filler, and acicular reinforcing filler; more preferably, the fibrous reinforcing filler comprises at least one of glass fibers, carbon fibers, aramid fibers, metal fibers; the flat plate-shaped reinforcing fiber comprises at least one of mica and talcum powder; the acicular reinforcing filler comprises at least one of potassium titanate whisker, wollastonite, aluminum borate whisker, xonotlite, calcium carbonate whisker, sepiolite and zinc oxide whisker.

Preferably, the reinforcing filler further comprises at least one of silica, aluminum nitride, alumina, barium carbonate, boron nitride, potassium titanate (non-whisker), kaolin, attapulgite, clay, pyrophyllite, carbon nanotubes, bentonite, calcium silicate, aluminum borate (non-whisker), barium sulfate, asbestos, glass beads, graphite, silicon carbide, sericite, calcium sulfate, hydrotalcite, and molybdenum disulfide.

Preferably, the components of the molding composition also comprise an antioxidant, a light aging agent and other functional auxiliaries.

Preferably, the molding composition is prepared by a process comprising: and uniformly mixing the semi-aromatic polyamide resin with various auxiliaries, putting the mixture into a double-screw extruder, adding a functional filler, and performing melt extrusion granulation at 330-340 ℃ to obtain the molding composition.

The invention has the beneficial effects that: the invention provides a semi-aromatic polyamide resin, which can remarkably improve the initial whiteness and the stability against thermo-oxidative aging of the obtained product by adding aromatic amine compounds, phosphorus-containing compounds and sulfur-containing compounds in specific proportions into the components serving as heat-resistant stabilizers and brighteners. The invention also provides a preparation method of the semi-aromatic polyamide resin, which is simple in operation steps and can realize industrial large-scale production. The invention also provides a molding composition prepared from the semi-aromatic polyamide resin, and the product also has high initial whiteness and good heat-resistant anti-yellowing performance.

Detailed Description

For better illustrating the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to specific examples, which are intended to be understood in detail, but not intended to limit the present invention.

Examples 1 to 6

Examples of the semi-aromatic polyamide resin according to the present invention, the formulations of the semi-aromatic polyamide resin in each example are shown in table 1.

The preparation method of the semi-aromatic polyamide resin described in the examples is: adding diamine monomer, diacid monomer, catalyst and end-capping reagent into a pressure reaction kettle with a condenser pipe, a magnetic coupling stirrer, a charging port, a gas phase port and a pressure explosion-proof device, adding deionized water accounting for 30 wt% of the total charging amount, aromatic amine compound, phosphorus-containing compound and sulfur-containing compound, vacuumizing, and introducing high-purity nitrogen as protective atmosphere to start reaction.

Gradually heating the reaction mixture to 220-230 ℃ from room temperature, stirring for 2-4 h at the temperature, opening an exhaust valve to slowly release pressure, discharging water vapor from the reaction container, and controlling the water discharge amount to keep the temperature and the pressure in the reactor unchanged. Directly discharging water until the water discharge amount reaches about 60-70% of the amount of the added deionized water; heating to 250-270 ℃ within 3 hours, and keeping the temperature for 1-2 hours; and opening a valve to discharge after the reaction is finished to obtain the prepolymer.

Drying the prepolymer at 100 ℃ for 4h, adding the dried prepolymer into a solid phase tackifying device, and performing solid phase tackifying reaction by using high-purity nitrogen as protective gas: firstly, heating to 210-220 ℃, keeping the temperature constant for 1-5 h, then continuously heating to 250-260 ℃ and keeping the temperature constant for 1-3 h. After the reaction is finished, cooling to 180 ℃, and keeping the temperature for 1-5 hours; finally, the temperature is reduced to room temperature and the material is discharged. And continuously sampling in the reaction process, and determining the final polymerization end point by sampling and testing the viscosity to obtain the semi-aromatic polyamide resin.

Comparative examples 1 to 3

The semi-aromatic polyamide resins of comparative examples 1 to 3 differ from examples 1 to 8 only in formulation, and formulations for respective comparative examples are shown in table 1.

The semi-aromatic polyamide resins described in examples 1 to 6 and comparative examples 1 to 3 were used together to prepare molding compositions, and the formulations of the molding compositions described in the respective examples are shown in Table 2.

The preparation method of the molding composition comprises the following steps: uniformly mixing the dried semi-aromatic polyamide resin with various auxiliaries by using a high-speed stirrer, adding the mixture from a main feeding port of a double-screw extruder, adding titanium dioxide and glass fiber into the double-screw extruder through a side feeding machine, and performing melt extrusion and granulation through the double-screw extruder at a set temperature of 330-340 ℃ to obtain a granular molding composition; the auxiliary agent comprises an antioxidant, a light aging agent and other auxiliary agents, wherein the antioxidant is a hindered phenol antioxidant commonly used for nylon, the light aging agent is TINUVIN 326 produced by BASF, and the other auxiliary agents are a lubricant and a nucleating agent.

In the components of the semi-aromatic polyamide resin according to the embodiment of the present invention, the diamine monomer includes decamethylenediamine and hexamethylenediamine; the diacid monomers include terephthalic acid, isophthalic acid, and adipic acid; the catalyst is sodium hypophosphite; the end-capping reagent is benzoic acid; the phosphorus-containing compound is 2, 6-di-tert-butyl-4-methylphenyl phenyl pentaerythritol diphosphite; the aromatic amine compound is 4.4 '-bis (alpha, alpha' -dimethylbenzyl) diphenylamine; the sulfur-containing compound is pentaerythritol tetrakis (3-laurylthiopropionate.

In order to verify the excellent performance of the semi-aromatic polyamide resin, the products obtained in examples 1 to 6 and comparative examples 1 to 3 were subjected to performance property tests.

The relative viscosity test method of the semi-aromatic polyamide resin is GB 12006.1-89;

the method for testing the melting point of the semi-aromatic polyamide resin comprises the following steps: ISO11357 (2009);

the semi-aromatic polyamide resin and the molding composition prepared therefrom have a Hunter whiteness (W) test method of: the semi-aromatic polyamide resin or the molding composition was injection-molded using an injection molding machine to prepare a rectangular sample plate having a length × width × thickness of 80mm × 50mm × 2mm, and then the sample plate was measured using an alexan CE-7000A type color difference meter. Testing to obtain the L, a and b values of the sample, and calculating the Hunter whiteness value of the sample by the following formula:

hunter whiteness W ═ 100- [ (100-L)²+a²+b²]^0.5；

Of the semi-aromatic polyamide resin and of the moulding composition prepared thereof: and (3) placing the prepared rectangular sample plate into a constant-temperature aging box with an automatic ventilation device for carrying out thermo-oxidative aging test, wherein the temperature of the aging box is 150 ℃, keeping the temperature for 24 hours, taking out the sample, cooling the sample to room temperature, and testing the Hunter whiteness of the sample plate again. The thermal-oxidative aging resistance of the samples is judged by comparing the Hunter whiteness of the samples before and after aging, and the samples with more reduced Hunter whiteness after constant-temperature aging show that the thermal-oxidative aging resistance of the samples is poorer.

The test results are shown in tables 1 and 2.

TABLE 1

As can be seen from table 1, the relative viscosity and melting point of the semi-aromatic polyamide resins obtained in examples 1 to 6 are not much different from those of comparative examples 1 to 3, but the initial whiteness and the aged whiteness of the semi-aromatic polyamide resins obtained in examples 1 to 6 are obviously higher than those of the products obtained in comparative examples 1 to 3, wherein the initial whiteness of the products obtained in examples can reach 91.2 to the maximum, and the initial whiteness of the products obtained in examples can still reach 85.4 to the maximum after aging, while the initial whiteness of comparative examples 1 to 2 lacking the aromatic amine compound, the phosphorus compound and the sulfur compound can still reach about 80, but can be significantly reduced after aging, and the whiteness of the products obtained in comparative example 3 without the preferred mixture ratio of the three components has a certain difference compared with the whiteness of example 1.

TABLE 2

As can be seen from Table 2, the molding compositions prepared in examples 1 to 6 have higher initial whiteness and stronger thermal aging resistance than the products obtained in comparative examples 1 to 3, similarly to the properties of the semi-aromatic polyamide resin as a raw material thereof. It is noted that, compared with comparative example 3, the initial whiteness of the products obtained in examples 1 to 6 is 95 or more, and the whiteness is still maintained at 90 or more after aging test, which shows that the proportion of the aromatic amine compound, the phosphorus compound and the sulfur compound in the semi-aromatic polyamide resin component has more obvious influence on the initial whiteness and the stability to thermal oxidative aging of the molding composition prepared from the semi-aromatic polyamide resin.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.