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CN-121975317-A - Low-warpage toughened polyhexamethylene adipamide material and preparation method thereof

CN121975317ACN 121975317 ACN121975317 ACN 121975317ACN-121975317-A

Abstract

The invention relates to the field of engineering plastic composite materials. A low-warpage toughened polyhexamethylene adipamide material and a preparation method thereof. The invention uses polyhexamethylene adipamide, glass fiber, polyhexamethylene adipamide-silicon dioxide reaction composite master batch and maleic anhydride grafted ethylene-1-octene copolymer master batch to cooperatively compound, and obtains granules through reaction extrusion and blending granulation. The warping amount of the material injection molding plate piece is 0.10-0.60mm, and the notch impact strength is 8-25kJ/m < 2 >. Solves the problem that the low warpage and the toughness of the polyhexamethylene adipamide glass fiber reinforced material are difficult to be compatible. Is suitable for injection molding products.

Inventors

  • TU WEI
  • LI LANG

Assignees

  • 东莞市众一新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20260310

Claims (10)

  1. 1. A low warpage toughened polyhexamethylene adipamide material, characterized by comprising the following components in percentage by mass based on the batch components for preparing the material, wherein the sum of the mass percentages of the components A to D is 100wt%: A. polyhexamethylene adipamide, 43-77wt%; B. 15-30wt% of glass fiber; C. 3-12wt% of polyhexamethylene adipamide-silicon dioxide reaction composite master batch; D. 5-15wt% of maleic anhydride grafted ethylene-1-octene copolymer master batch; Wherein: the polyhexamethylene adipamide-silicon dioxide reaction composite master batch is prepared by reacting and extruding polyhexamethylene adipamide, pyromellitic dianhydride and epoxy silanized silicon dioxide; The maleic anhydride grafted ethylene-1-octene copolymer master batch is prepared by grafting ethylene-1-octene copolymer, maleic anhydride and dicumyl peroxide in the reaction extrusion; The component A polyhexamethylene adipamide is a matrix resin which is added independently, and the polyhexamethylene adipamide contained in the component C does not account for the mass of the component A.
  2. 2. The material of claim 1, wherein the epoxy silanized silica for the polyhexamethylene adipamide-silica reaction composite masterbatch is prepared by: A1. The raw materials are prepared from 100 parts by mass of silicon dioxide, 2-10 parts by mass of 3-glycidoxypropyl trimethoxy silane, 0.05-0.50 part by mass of acetic acid and 100-300 parts by mass of deionized water; A2. Hydrolysis-coupling, namely, carrying out hydrolysis-coupling at 20-30 ℃, adopting mechanical stirring, stirring at 200-800rpm, and stirring for 0.5-2.0h under the condition of pH value of 4.0-5.5; A3. filtering, washing with deionized water for 1-3 times, wherein the dosage of deionized water used in each washing is 2-10 times of the mass of the silicon dioxide, the soaking or stirring time is 1-10min, and the pH of the filtrate is 6.0-8.0 at the end of washing; A4. Drying and curing, namely drying for 2-6 hours at 100-130 ℃; A5. And (3) drying to constant weight, wherein the constant weight is judged that the adjacent two times are weighed for not less than 1h, the mass change rate is not more than 0.1%, the water content of the obtained powder is 0.10-1.00wt%, and the water content is measured by a Karl Fischer method to obtain the epoxy silanized silicon dioxide.
  3. 3. The material of claim 1, wherein the polyhexamethylene adipamide-silica reaction composite masterbatch is prepared by: B1. Raw material preparation, namely 100 parts by mass of polyhexamethylene adipamide, 0.05-0.30 part by mass of pyromellitic dianhydride and 0.5-5.0 parts by mass of prepared epoxy silanized silicon dioxide; B2. Premixing and drying, namely mixing the raw materials and drying for 2-8 hours at 80-110 ℃; B3. Performing melt reaction extrusion in a twin-screw extruder at 260-290 ℃, wherein the screw speed is 150-450rpm, and vacuum exhaust is arranged at the tail end of a machine barrel to ensure that the absolute pressure of an exhaust port is 0.005-0.030MPa and the residence time is 30-120s; B4. Granulating, namely performing water cooling or air cooling granulation to obtain master batches; B5. And (3) end point criterion and quality control, wherein the melt mass flow rate of the master batch is 10-40g/10min, and the melt mass flow rate is measured according to GB/T3682.1-2018 under the conditions of 275 ℃ and 2.16kg load, so as to obtain the polyhexamethylene adipamide-silicon dioxide reaction composite master batch.
  4. 4. The material of claim 1, wherein the maleic anhydride grafted ethylene-1-octene copolymer masterbatch is prepared by: C1. Raw material preparation comprises 100 parts by mass of ethylene-1-octene copolymer, 0.5-3.0 parts by mass of maleic anhydride and 0.05-0.30 parts by mass of dicumyl peroxide; C2. The grafting reaction extrusion is carried out in a double-screw extruder at 170-210 ℃, the screw rotating speed is 200-500rpm, the vacuum exhaust is arranged at the tail end of the machine barrel, the absolute pressure of the exhaust port is 0.005-0.030MPa, and the residence time is 30-180s; C3 Granulating, namely water-cooling or air-cooling granulating to obtain master batches; C4. The grafting degree of the maleic anhydride in the master batch is 0.3-2.0wt%, the grafting degree of the maleic anhydride is based on the dry basis of the ethylene-1-octene copolymer, the free maleic anhydride is removed by reflux-extracting a sample with acetone at 60 ℃ for not less than 2 hours, then the residual sample is hydrolyzed and calculated by adopting an acid-base titration method, the content of the free maleic anhydride is 0.01-0.30wt%, the content of the free maleic anhydride is based on the dry basis of the master batch, the reflux-extracting the sample with acetone at 60 ℃ for not less than 2 hours, and then the quantitative calculation of an extracting solution is carried out by adopting an acid-base titration method, so that the maleic anhydride grafted ethylene-1-octene copolymer master batch is obtained.
  5. 5. The material of claim 1, wherein the glass fibers are surface treated with 3-glycidoxypropyl trimethoxysilane prior to blending with polyhexamethylene adipamide, the surface treatment being performed by: D1. Raw material preparation comprises 100 parts by mass of glass fiber, 0.2-2.0 parts by mass of 3-glycidoxypropyl trimethoxy silane, 0.05-0.50 parts by mass of acetic acid and 100-500 parts by mass of deionized water; D2. Hydrolysis-coating, namely, mechanically stirring at 20-30 ℃, adding 3-glycidoxypropyl trimethoxysilane into deionized water at the stirring speed of 200-800rpm, adjusting the pH to 4.0-5.5 by acetic acid, stirring for 0.5-2.0h, and enabling the glass fiber to be in contact with the hydrolysis system in an impregnation mode for 10-60min; D3. Drying and curing, namely drying for 1-4 hours at the temperature of 110-140 ℃; D4. And (3) drying to constant weight, wherein the constant weight is judged that the adjacent two times are weighed at intervals of not less than 1h, the mass change rate is not more than 0.1%, the coating amount of the surface treating agent of the treated glass fiber is 0.20-1.00wt%, the coating amount is based on the dry basis weight of the treated glass fiber, and the weight loss of organic matters when the glass fiber is burned to constant weight is measured by thermogravimetric analysis at 550 ℃ to obtain the surface treated glass fiber.
  6. 6. The material according to claim 1, wherein the glass fiber is a chopped glass fiber having a length of 2.0 to 6.0mm and a diameter of 7 to 17 μm, the content of silica in the polyhexamethylene adipamide-silica reaction composite master batch is 0.5 to 4.7wt%, and the primary particle diameter of silica is 5 to 50nm.
  7. 7. The material according to claim 1, wherein the warpage amount of the plate member having a length of 150-200mm, a width of 100-150mm and a thickness of 1.5-3.0mm, which is injection molded using the material, is 0.10-0.60mm, the plate member is conditioned for 24 hours under a condition of 23 ℃ and a relative humidity of 50% and then placed on a standard plane, the maximum out-of-plane height difference of the plate member is used as a measurement value of the warpage amount, and the notched impact strength is 8-25kJ/m2, wherein the notched impact strength is measured using an independently injection molded 80mm x 10mm x 4mm standard sample, the notched depth is 2.0mm, and the notched condition is measured according to GB/T1043.1-2008A type at 23 ℃.
  8. 8. A method of preparing a low warpage toughened polyhexamethylene adipamide material as claimed in any one of claims 1 to 7 comprising the steps of: s1, providing epoxy silanized silicon dioxide; S2, providing polyhexamethylene adipamide-silicon dioxide reaction composite master batch; S3, providing a maleic anhydride grafted ethylene-1-octene copolymer master batch; S4, blending and granulating polyhexamethylene adipamide, the polyhexamethylene adipamide-silicon dioxide reaction composite master batch provided in the step S2, the maleic anhydride grafted ethylene-1-octene copolymer master batch provided in the step S3 and glass fiber in a double-screw extruder at 250-290 ℃, wherein the rotating speed of the screw is 150-450rpm, and the tail end of a machine barrel is provided with vacuum exhaust, so that the absolute pressure of an exhaust port is 0.005-0.030MPa; s5, injection molding the granules obtained in the step S4 to obtain the product.
  9. 9. The method of preparing as claimed in claim 8, wherein: Drying polyhexamethylene adipamide at 80-110 ℃ for 4-12h to make the water content of the polyhexamethylene adipamide be 0.02-0.20wt% before the step S4; In the step S4, the polyhexamethylene adipamide-silicon dioxide reaction composite master batch and the maleic anhydride grafted ethylene-1-octene copolymer master batch are added simultaneously with the polyhexamethylene adipamide at a main feeding port of an extruder; In the step S4, the glass fiber is added in a side feeding mode, the side feeding position is positioned in the 3 rd-8 th temperature zone of the double-screw extruder, and the glass fiber is subjected to surface treatment by 3-glycidoxypropyl trimethoxy silane; The blending granulation residence time of the step S4 is 30-120S.
  10. 10. The method according to claim 8, wherein the injection mold in step S5 has a temperature of 70 to 100 ℃, a cylinder temperature of 265 to 290 ℃, an injection pressure of 60 to 120MPa, and a cooling time of 20 to 40S.

Description

Low-warpage toughened polyhexamethylene adipamide material and preparation method thereof Technical Field The invention relates to the field of engineering plastic composite materials, in particular to a low-warpage toughened polyhexamethylene adipamide material and a preparation method thereof. Background Polyhexamethylene adipamide is often used in combination with glass fibers in injection molded articles to improve load bearing and heat resistance, and is suitable for structural components such as flat panels and the like which have high requirements for dimensional consistency. In the molding and service process of the product, the material needs to keep stable deformation level under the change of temperature and humidity conditions, and the notch impact strength is considered on the basis of ensuring rigidity so as to reduce assembly deviation and use failure risk. Meanwhile, factors such as the length and diameter of the glass fiber, the coating amount of the surface treatment agent, the water content of polyhexamethylene adipamide and the like can directly influence the melt state and fiber distribution in the blending granulation and injection molding processes, thereby influencing the repeatability of the warping amount. Therefore, the field puts higher requirements on the formula and the preparation method, namely, stable melt mass flow rate and batch consistency are realized in the reaction extrusion and blending granulation stage, and the comprehensive performance with low warpage and toughness is obtained in a subsequent injection molding window. In addition, to ensure comparability of subsequent performance evaluation, the warpage and notched impact strength also need to adopt definite sample preparation and testing conditions. In polyhexamethylene adipamide and glass fiber systems, it is generally necessary to improve the dimensional stability of the system and the uniformity of fiber distribution in order to reduce warpage, but to introduce an effective toughening phase to improve notch impact strength and ensure the combination of the toughening phase and a matrix, and at the same time, the injection molding process also requires that the material maintain a stable melt mass flow rate under the conditions of blending granulation and injection molding, and avoid the generation of excessive free maleic anhydride content in the modification process. The prior proposal is usually started from the control of the morphology of the glass fiber or the introduction of the toughening agent, and lacks the cooperative design of the polyhexamethylene adipamide-silicon dioxide reaction composite master batch and the maleic anhydride grafted ethylene-1-octene copolymer master batch. The Chinese patent with publication number CN120842840A discloses a low-warpage PA66 material and a preparation method thereof, and the Chinese patent with publication number CN113524623A discloses a method for improving the impact performance of MCA flame-retardant PA66, but still needs to further perfect the formula and the preparation path under the goals of low warpage, toughening and combination. Disclosure of Invention The invention aims to provide a low-warpage toughened polyhexamethylene adipamide material and a preparation method thereof, and solves the problems that the control of the warpage of an injection molding flat piece and the improvement of notch impact strength of a traditional polyhexamethylene adipamide and glass fiber system are difficult to be compatible, and the grafting degree and the content of free maleic anhydride in a modified system are difficult to be controlled simultaneously. According to the invention, through the synergistic compounding of the polyhexamethylene adipamide-silicon dioxide reaction composite master batch and the maleic anhydride grafted ethylene-1-octene copolymer master batch and the blending granulation condition of the surface treatment glass fiber and vacuum exhaust, the warpage of the material is reduced and the notch impact strength is improved while the stable melt mass flow rate is maintained. In order to achieve the above object, the present invention provides the following technical solutions: the low-warpage toughened polyhexamethylene adipamide material comprises the following components in percentage by mass based on the batch components for preparing the material, wherein the sum of the mass percentages of the components A to D is 100wt%: A. polyhexamethylene adipamide, 43-77wt%; B. 15-30wt% of glass fiber; C. 3-12wt% of polyhexamethylene adipamide-silicon dioxide reaction composite master batch; D. 5-15wt% of maleic anhydride grafted ethylene-1-octene copolymer master batch; Wherein: the polyhexamethylene adipamide-silicon dioxide reaction composite master batch is prepared by reacting and extruding polyhexamethylene adipamide, pyromellitic dianhydride and epoxy silanized silicon dioxide; The maleic anhydride grafted ethylene-1-octene copolymer master batch is