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CN-122011703-A - PBT3D printing material and preparation method thereof

CN122011703ACN 122011703 ACN122011703 ACN 122011703ACN-122011703-A

Abstract

The invention discloses a PBT3D printing material and a preparation method thereof, and relates to the field of high polymer materials. The PBT3D printing material comprises, by weight, 80-95 parts of PBT resin, 5-20 parts of ternary polymerization glycidyl ester, 0.1-1 part of an antioxidant and 0-5 parts of optional other auxiliary agents. According to the PBT3D printing material, ternary polymerization glycidyl ester with specific composition and molecular weight is creatively introduced as a crystallization regulator of the PBT, and epoxy functional groups in molecular chains of the ternary polymerization glycidyl ester and terminal carboxyl groups or terminal hydroxyl groups of the PBT are subjected to chemical reaction to form a grafting or crosslinking structure, so that the movement capability of the molecular chains of the PBT is effectively limited, but crystallization is not completely inhibited, and the final crystallization degree of the material is accurately controlled in a moderate range of 25% -40%, but is not simply improved or reduced.

Inventors

  • SUN JINGLIAN
  • WANG NING
  • FENG ZHEN

Assignees

  • 宁波兴立新材料有限公司

Dates

Publication Date
20260512
Application Date
20260319

Claims (10)

  1. 1. The PBT3D printing material is characterized by comprising, by weight, 80-95 parts of PBT resin, 5-20 parts of ternary polymerization glycidyl ester, 0.1-1 part of an antioxidant and 0-5 parts of optional other auxiliary agents; the other auxiliary agent is one or two of a lubricant and a pigment; The ternary polymerization glycidyl ester is a ternary copolymer of glycidyl methacrylate, ethylene and methyl acrylate, and forms a grafting or crosslinking structure through chemical reaction between epoxy functional groups in a molecular chain and terminal carboxyl groups or terminal hydroxyl groups of the PBT resin.
  2. 2. The PBT3D printing material according to claim 1, wherein the ternary polymerization glycidyl ester has a weight content of 5% -15% of glycidyl methacrylate units, a weight content of 60% -75% of ethylene units and a weight content of 20% -30% of methyl acrylate units, and the chemical reaction can limit the molecular chain movement capability of PBT but not completely inhibit crystallization of the PBT, so that the crystallinity of the PBT3D printing material is regulated to 25% -40%.
  3. 3. The PBT3D printing material according to claim 1, wherein the intrinsic viscosity of the PBT resin is 0.9-1.0 dL/g, and the antioxidant is formed by compounding pentaerythritol tetra-beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate and tris (2, 4-di-tert-butylphenyl) phosphite in a ratio of 1:2.
  4. 4. The PBT3D printing material according to claim 1, wherein the supercooling degree of the PBT3D printing material is 40.6-45.7 ℃, the width of a printing process window is more than or equal to 25 ℃, the printing without warping can be realized within the temperature range of a printing platform of 55-90 ℃, and the tensile strength of a printing product is more than or equal to 65MPa and the impact strength is more than or equal to 12kJ/m <2 >.
  5. 5. The PBT3D printing material according to claim 1, wherein the ternary polymerized glycidyl ester has a number average molecular weight of 10000-30000 and a molecular weight distribution index of 1.8-2.5.
  6. 6. The PBT3D printing material according to claim 1, further comprising 0.5-2 parts of an inorganic modifier, wherein the inorganic modifier is nano silicon dioxide modified by a silane coupling agent KH-550, has a particle size of 50-100 nm, and can cooperate with ternary polymerization glycidyl ester.
  7. 7. A method for preparing the PBT3D printing material, for preparing the PBT3D printing material according to any one of claims 1 to 6, characterized in that the preparation method comprises the steps of: s1, drying, namely vacuum drying the PBT resin for 4-6 hours at the temperature of 100-120 ℃ to remove water; S2, premixing, namely placing the dried PBT resin, the ternary polymerization glycidyl ester, the antioxidant, the optional other auxiliary agents and the optional inorganic modifier into a high-speed mixer, and mixing for 5-10 minutes to obtain a premix; S3, melt blending, namely feeding the premix into a double-screw extruder with the length-diameter ratio of 40:1, controlling the temperature of each section of the screw to be 220 ℃ in a feeding section, 230-240 ℃ in a homogenizing section and 250 ℃ in a machine head, wherein the rotating speed of the screw is 200-400 rpm, the vacuum degree is-0.06 to-0.08, and obtaining PBT3D printing material master batch through melt extrusion, cooling, drawing and granulating; S4, secondary drying, namely drying the master batch prepared in the step 3 at 80-100 ℃ for 3-5 hours for standby.
  8. 8. The preparation method of the PBT3D printing material according to claim 7, wherein the step S2 is performed in a sectional gradient mixing mode, specifically, the PBT resin and the ternary polymerization glycidyl ester are mixed for 3-4 minutes at a speed of 800-1000 rpm, then an antioxidant, an inorganic modifier and other auxiliary agents are added, the speed of rotation is adjusted to 1100-1200 rpm, mixing is continued for 2-6 minutes, and the temperature of materials is controlled to be 50-60 ℃ through jacket water cooling in the mixing process.
  9. 9. The preparation method of the PBT3D printing material according to claim 7, wherein the step of melt blending adopts a sectional temperature control reaction and a dynamic heat preservation mode, the sectional temperature control reaction is specifically that a gradient temperature rise from a feeding section to a homogenizing section is 220 ℃ to 225 ℃ to 230 ℃ to 240 ℃, the residence time of the homogenizing section is 4 to 5 minutes, and a gradient cooling from 45 ℃ to 35 ℃ to 25 ℃ is adopted after the discharge of a machine head.
  10. 10. The preparation method of the PBT3D printing material according to claim 7, wherein the step S4 is additionally provided with a master batch performance pre-detection step after secondary drying, wherein the detection indexes are 25% -40% of crystallinity, less than or equal to 0.05% of moisture content and 15-25 g/10min of melt index, and the test condition is 230 ℃ per 2.16kg.

Description

PBT3D printing material and preparation method thereof Technical Field The invention relates to the field of high polymer materials, in particular to a PBT3D printing material and a preparation method thereof. Background Polybutylene terephthalate (PBT) is an excellent semi-crystalline thermoplastic engineering plastic, has excellent mechanical properties, chemical resistance, electrical insulation and processing fluidity, and is widely applied to the fields of automobiles, electronics, electrics and the like. As a semi-crystalline polyester material, the PBT is theoretically suitable for the high-precision molding requirement of 3D printing by virtue of the characteristics of low water absorption and high dimensional stability, wherein the PBT resin with the intrinsic viscosity of 0.9-1.0 dL/g has good processing fluidity and mechanical strength, and is one of the preferable base materials of the 3D printing material. In recent years, with the rapid development of 3D printing technology, application of PBT to Fused Deposition Modeling (FDM) technology has received extensive attention, and it is expected to realize rapid preparation of engineering parts with complex structures. However, the inherent rapid crystallization characteristics of PBT present significant challenges to the FDM printing process, severely limiting its large-scale application in the 3D printing field, with the following specific problems: 1. the crystallization shrinkage rate is high, the PBT can generate larger volume shrinkage in the process of cooling and crystallizing from a melt, the shrinkage is extremely easy to lead to product warpage and deformation in the FDM process of layer-by-layer printing, even the PBT falls off from a printing platform, and the printing failure rate is high, which is also a core pain point for restricting the PBT to be used for FDM printing. 2. The processing window is narrow, the crystallization temperature (Tc) and the melting point (Tm) of the PBT are relatively close, and the supercooling degree (Tm-Tc) of the PBT is relatively small. This means that the melt crystallizes rapidly after extrusion and the interlayer bonding time is short. If the temperature of the printing platform is set to be slightly low, the crystallization is too fast, the interlayer adhesion is not firm, and if the temperature of the printing platform is set to be slightly high, the product is shaped slowly, and collapse is easy to occur. The narrow process window has extremely strict requirements on setting printing parameters, the width of a common pure PBT printing process window is usually less than 5 ℃, and the process adaptability is extremely poor. 3. The performance stability is poor, namely the uneven cooling condition in the printing process can cause large difference of crystallinity of each part of the product, so that uneven internal stress distribution and performance anisotropy are caused, the dimensional accuracy and mechanical property stability of the final product are affected, and the use requirement of engineering parts is difficult to meet. At present, the method for improving the printing performance of the PBT mainly comprises the steps of adding inorganic nucleating agents (such as talcum powder and montmorillonite) and polymer toughening agents (such as elastomer) and the like. The addition of the nucleating agent can refine grains, but often further quickens the crystallization rate and aggravates the warping risk, while the addition of the elastomer can improve toughness, but generally reduces the rigidity and the heat resistance of the material, and the regulation and control of the crystallization degree are not accurate enough, so that the problem of FDM printing of PBT can not be fundamentally solved. In addition, some technologies attempt to improve the PBT performance by adding an inorganic modifier, but do not solve the problem of poor compatibility of the modifier and the PBT matrix, and phase separation is easy to occur, so that the mechanical properties of the material are reduced. Although the inorganic particles modified by the silane coupling agent can improve the compatibility with polyester materials, how to realize the dual effects of crystallization regulation and performance improvement by the synergistic effect of the inorganic particles and the crystallization regulator is still a technical problem to be solved in the field. Therefore, a novel method capable of effectively regulating and controlling the crystallization kinetics and the final crystallinity of the PBT is developed, the problem of FDM printing is fundamentally solved, and meanwhile, the mechanical property, the heat resistance and the processing fluidity of the material are simultaneously considered, so that the method has important industrial application value. Disclosure of Invention The invention aims to provide a PBT3D printing material and a preparation method thereof, which are used for solving the problems in t