CN111849161A - A thermoplastic composite material and its preparation method and high-precision plastic parts - Google Patents

Abstract

The embodiment of the invention provides a thermoplastic composite material taking engineering plastics as a matrix, which comprises the following components in parts by weight: 20-80 parts of thermoplastic engineering plastic, 20-80 parts of functional filler, 1-10 parts of coupling agent, 0.5-1 part of antioxidant and 0.5-2 parts of other auxiliary agents, wherein the functional filler comprises 0-80 parts of negative thermal expansion material and 0-80 parts of silicon dioxide microspheres, and the total weight parts of the thermoplastic engineering plastic and the functional filler is 100 parts. The thermoplastic composite material has extremely low linear thermal expansion coefficient, good heat resistance and high stability, can be used for preparing high-precision structural members such as optical communication equipment and 5G equipment, and improves the long-term running precision of precision equipment products. The embodiment of the invention also provides a preparation method of the composite material and a high-precision plastic part.

Description

A thermoplastic composite material and its preparation method and high-precision plastic parts

technical field

The invention relates to the technical field of resin composite materials, in particular to a thermoplastic composite material with an ultra-low thermal expansion coefficient, a preparation method thereof, and a high-precision plastic part.

Background technique

Thermoplastic engineering plastics have the characteristics of high rigidity, small creep, high comprehensive strength and good formability, and can be used as engineering structural materials instead of metals. However, compared with metals, thermoplastic engineering plastics have weak intermolecular forces and relatively large thermal expansion coefficients, so their dimensional stability is low. It will produce thermal deformation, which will reduce the long-term operation accuracy of the components, thus limiting the application of thermoplastic engineering plastics in precision equipment and instruments.

Therefore, in order to meet the requirements of high dimensional stability of precision components, it is urgent to develop a thermoplastic composite material with low thermal expansion coefficient and high stability.

SUMMARY OF THE INVENTION

In view of this, the first aspect of the embodiments of the present invention provides a thermoplastic composite material, which has an ultra-low thermal expansion coefficient, good heat resistance, and high stability, which can be used for the preparation of high-precision components and improve the long-term performance of precision equipment and instruments. The operation accuracy is to solve the problem that the existing thermoplastic engineering plastics are difficult to meet the high dimensional stability requirements of precision parts due to the large thermal expansion coefficient under the condition of external temperature shock changes.

Specifically, the first aspect of the embodiments of the present invention provides a thermoplastic composite material, and the composite material includes the following components in parts by weight:

Wherein, the functional filler includes 0-80 parts of negative thermal expansion material and 0-80 parts of silica microbeads, and the total weight of the thermoplastic engineering plastic and the functional filler is 100 parts.

In the first aspect of the present invention, further, the weight part of the negative thermal expansion material is 20-80 parts, and the weight part of the silica microbeads is 0-20 parts. Further, the parts by weight of the negative thermal expansion material are 30-70 parts; further, 45-70 parts, 50-70 parts. Further, the parts by weight of the silica microbeads are 0-10 parts.

In the first aspect of the present invention, further, the weight part of the silica microbeads is 40-80 parts, and the weight part of the negative thermal expansion material is 0-30 parts. Further, the weight parts of the silica microbeads are 50-80 parts, and further 60-70 parts.

In the first aspect of the present invention, the ratio of the thermoplastic engineering plastic to the functional filler is 1:0.25-4, further the ratio of the weight is 1:1-4, and furthermore The ratio of numbers is 1:1-3 or 1:1.5-2.5. Thermoplastic composite materials with different thermal expansion coefficients can be obtained by controlling the weight ratio of the thermoplastic engineering plastic to the functional filler.

In the first aspect of the present invention, the average linear expansion coefficient of the negative thermal expansion material in the temperature range of -60°C to 350°C is negative in at least one of the three-dimensional directions. Specifically, the negative thermal expansion material includes one of pyrophosphates, pyrotungstates, tungstates, manganese nitrogen compounds, cordierite, β-eucryptite, and garnet negative thermal expansion materials. one or more. More specifically, the pyrophosphate-based negative thermal expansion material includes ZrP ₂ O ₇ , the pyrotungstate-based negative thermal expansion material includes ZrW ₂ O ₈ , and the tungstate-based negative thermal expansion material includes Al ₂ W ₃ O ₁₂ , Y ₂ W ₃ O ₁₂ , Sc ₂ W ₃ O ₁₂ , the manganese-nitrogen compound-based negative thermal expansion material includes Mn ₃ AN, and A in the Mn ₃ AN is Zn, Ga, Cu, Fe, and Ge. One or more, the cordierite-based negative thermal expansion material includes Mg ₂ Al ₄ Si ₅ O ₁₈ , the β-eucryptite-based negative thermal expansion material includes LiAl ₂ Si ₂ O ₈ , and the garnet-based negative thermal expansion material Materials include NaZr ₂ (PO ₄ ) ₃ , KZr ₂ (PO ₄ ) ₃ .

In the first aspect of the present invention, the particle size of the silica microbeads is in the range of 1 μm-50 μm, and the silica microbeads are solid microspheres or hollow microspheres.

In the first aspect of the present invention, further, the weight part of the thermoplastic engineering plastic is 20-60 parts, and the weight part of the functional filler is 40-80 parts.

In the first aspect of the present invention, the thermoplastic engineering plastics may be of existing commonly used types, and may specifically include polyamide, polycarbonate, polyoxymethylene, modified polyphenylene ether, thermoplastic polyester, polyphenylene sulfide, polyamide One or more of etherimide, liquid crystal polymer, polyethersulfone, polyaryletherketone and fluororesin.

In the first aspect of the present invention, the coupling agent includes one or more of a silane coupling agent and a titanate coupling agent. The antioxidants include one or more of hindered phenols, aromatic amines, phosphites and thioesters. The other adjuvants include one or more of toughening agents, lubricants, antistatic agents and toners.

In the first aspect of the present invention, the thermoplastic composite material has an ultra-low thermal expansion coefficient, specifically, the average thermal expansion coefficient of the thermoplastic composite material in the temperature range of -60°C to 350°C is 0-23×10 ^-6 /°C.

The thermoplastic composite material provided in the first aspect of the embodiment of the present invention has good heat resistance, has an ultra-low thermal expansion coefficient (0-23×10 ^-6 /°C), and the thermal expansion coefficient is adjustable within a certain range. It is used for Forming of precision structural parts, high-precision plastic parts can be rapidly formed by injection molding process, and can be used for products that require extremely high dimensional accuracy, such as optical communication parts, high-precision antenna parts, etc.

A second aspect of the embodiments of the present invention provides a method for preparing a thermoplastic composite material, comprising the following steps:

In parts by weight, 20-80 parts of functional filler and 1-10 parts of coupling agent are added into a high-speed mixer to mix evenly, and the mixture is obtained after drying; the functional filler includes 0-80 parts of negative thermal expansion material and 0-80 parts of silica microbeads;

The mixture is added into a twin-screw extruder together with 20-80 parts of thermoplastic engineering plastics, 0.5-1 part of antioxidant, and 0.5-2 parts of other auxiliary agents, and then extruded and pelletized to obtain a thermoplastic composite material , wherein the total weight of the thermoplastic engineering plastic and the functional filler is 100 parts.

In the second aspect of the present invention, the screw speed of the twin-screw extruder is 150-300 rpm, and the extrusion temperature is 180-380°C.

In the second aspect of the present invention, the mixing time is 1min-30min.

The preparation method of the thermoplastic composite material provided by the second aspect of the embodiment of the present invention has a simple process and is suitable for large-scale industrial production.

A third aspect of the embodiments of the present invention provides a high-precision plastic part, and the high-precision plastic part is prepared by using the thermoplastic composite material described in the first aspect of the present invention. Specifically, the high-precision plastic components include antenna brackets, antenna housings, diffraction gratings, optical fiber connectors, and mobile phone precision structural components.

The high-precision composite material component provided by the third aspect of the embodiment of the present invention has high dimensional accuracy under long-term operation, high reliability against temperature shock, and long fatigue life.

Detailed ways

The present invention will be further described below with reference to specific embodiments.

Thermal expansion and cold contraction are the basic properties of most substances, and this property has brought many adverse effects to the manufacturing industry, especially in the field of precision equipment manufacturing and precision testing. The influence of thermal deformation on the actual machining accuracy and measurement accuracy cannot be ignored. For these products that require high long-term dimensional stability, good dimensional stability is required from the beginning of the raw material. Among the commonly used engineering structural materials, the plastic materials have the greatest impact on the size due to changes in ambient temperature. Engineering plastics have good rigidity, mechanical strength, heat resistance and physical and chemical resistance, and are lighter in weight and higher in molding efficiency than metals. However, thermoplastic engineering plastics have a relatively large thermal expansion coefficient due to weak intermolecular forces. When they are used to form precision parts, the long-term running accuracy of the obtained precision parts will be affected by the thermal expansion and contraction of the material. This limits the application of thermoplastic resins in precision equipment and instruments.

In order to solve the above problems, an embodiment of the present invention provides a thermoplastic composite material, and the composite material includes the following components in parts by weight:

Wherein, the functional filler includes 0-80 parts of negative thermal expansion material and 0-80 parts of silica microbeads, and the total weight of the thermoplastic engineering plastic and the functional filler is 100 parts.

The thermoplastic composite material provided by the embodiment of the present invention is obtained by compounding negative thermal expansion materials and/or silica microbeads with thermoplastic engineering plastics, and has an ultra-low thermal expansion coefficient, and the thermal expansion coefficient is adjustable within a certain range.

In an embodiment of the present invention, optionally, the weight portion of the negative thermal expansion material is 20-80 parts, and the weight portion of the silica microbeads is 0-20 parts. Further, the parts by weight of the negative thermal expansion material are 30-70 parts; further, 45-70 parts, 50-70 parts. In some embodiments, the weight part of the silica microbeads is 0, and in other embodiments, the weight part of the silica microbeads is greater than 0 and less than or equal to 20. Further, the parts by weight of the silica microbeads are 0-10 parts. In the embodiment system of the present invention, the negative thermal expansion material is used as the main functional filler, and the addition of a small amount of silica microspheres can act as a forming aid, which can improve the fluidity and formability of the composite material. Since the negative thermal expansion material has a negative thermal expansion coefficient, and according to the composite material mixing law (ROM), the thermal expansion coefficient of each component of the composite material is additive, so the composite material of this embodiment has an ultra-low thermal expansion coefficient, and by controlling the negative thermal expansion The type and amount of material added can make the thermal expansion coefficient adjustable within a certain range.

The negative thermal expansion material refers to a class of compounds whose average linear expansion coefficient or average volume expansion coefficient is negative in a certain temperature range, and the material has the property of thermal contraction and cold expansion in a specific temperature range. Specifically, in the embodiment of the present invention, the linear expansion coefficient of the negative thermal expansion material in the temperature range of -60°C to 350°C is negative in at least one direction in the three-dimensional direction, that is, it exhibits heat in at least one direction. The phenomenon of shrinkage and expansion. In an embodiment of the present invention, the negative thermal expansion material includes at least one of an isotropic negative thermal expansion material and an anisotropic negative thermal expansion material. Specifically, the linear expansion coefficient of the isotropic negative thermal expansion material is negative in all directions; further, the linear expansion coefficient is an equal negative value in all directions, and the isotropic negative thermal expansion material has a negative value. It exhibits consistent inflation behavior in all directions. The anisotropic negative thermal expansion material means that the coefficient of linear expansion is negative in some directions, and positive or zero in other directions, thus showing inconsistent expansion behavior in all directions. In the embodiment of the present invention, the negative thermal expansion material is preferably an isotropic negative thermal expansion material. Since the expansion behavior in all directions is consistent, the composite material can have a more uniform and stable thermal stress, thereby further enabling the composite material to have Higher stability, fatigue life and thermal shock resistance.

In the embodiment of the present invention, the negative thermal expansion material may include different types, specifically, the negative thermal expansion material may be selected from pyrophosphates, pyrotungstates, tungstates, manganese nitrogen compounds, and cordy. One or more of bluestone, β-eucryptite, and garnet negative thermal expansion materials. More specifically, the pyrophosphate-based negative thermal expansion material includes ZrP ₂ O ₇ ; the pyrotungstate-based negative thermal expansion material includes ZrW ₂ O ₈ ; the tungstate-based negative thermal expansion material includes Al ₂ W ₃ O ₁₂ , Y ₂ W ₃ O ₁₂ , Sc ₂ W ₃ O ₁₂ ; the manganese-nitrogen compound-based negative thermal expansion material includes Mn ₃ AN, and A in the Mn ₃ AN is Zn, Ga, Cu, Fe, and Ge. One or more, wherein Mn can be partially substituted by other elements (such as Fe, etc.); the cordierite-based negative thermal expansion material includes Mg ₂ Al ₄ Si ₅ O ₁₈ ; the β-eucryptite-based negative thermal expansion material includes LiAl ₂ Si ₂ O ₈ ; the garnet-based negative thermal expansion materials include NaZr ₂ (PO ₄ ) ₃ and KZr ₂ (PO ₄ ) ₃ . The above specific negative thermal expansion materials are only examples, and the present invention is not limited to the above listed negative thermal expansion materials.

Different types of negative thermal expansion materials mentioned above have different negative expansion mechanisms. For example, pyrophosphates (such as ZrP ₂ O ₇ )/pyrotungstates (such as ZrW ₂ O ₈ ) are due to the presence of M1-O-M2 bonds in their crystal structures (M1, M2 are metal atoms, O is a bridge atoms), and the bond strength of the MO bond is high enough that the bond length does not change with temperature, and the energy required for the lateral thermal vibration of the oxygen bridge atom is low, so when the oxygen atom vibrates laterally, it will cause non-bonded M1 and The distance between M2 becomes smaller, which leads to the rotational coupling of the crystal structure, and finally reduces the total volume of the crystal, showing the property of thermal contraction and cold expansion. Among the manganese-nitrogen compounds, the manganese-nitrogen compounds with the anti-perovskite structure will undergo magnetic transformation under certain temperature conditions. Taking Mn ₃ CuN as an example, with the decrease of temperature, the lattice expansion caused by the magnetic order increases. When the lattice shrinkage is greater than that caused by phonon thermal vibration, the material exhibits negative thermal expansion behavior, and the thermal expansion coefficient of manganese-nitrogen compound materials can be adjusted in a wide range, up to -25ppm×10 ^-6 /℃. The expansion characteristics of β-eucryptite are anisotropic, and β-eucryptite is a hexagonal crystal system similar to high temperature quartz. When the temperature increases, Li ⁺ will migrate from the tetrahedral coordination center to the octahedral position. The transformation process will cause the a and b axes of the crystal to expand and the c axis to shrink, thus showing the characteristics of negative expansion in a single direction.

Due to the addition of negative thermal expansion materials, in addition to reducing the thermal expansion coefficient of the composite material compared with the engineering plastic substrate, the heat resistance is better, and the flame retardant performance is better, but also reflects different performance improvements. For example, the composite material also has The advantages of high dielectric constant and low dielectric loss, and due to the good metallicity and mechanical strength of some negative thermal expansion materials (such as manganese-nitrogen compounds), compounding them with thermoplastic engineering plastics can obtain high mechanical strength, and electrical conductivity and performance. Thermoplastic composite material with good thermal conductivity.

In another embodiment of the present invention, optionally, the weight part of the silica microbeads is 40-80 parts, and the weight part of the negative thermal expansion material is 0-30 parts. Further, the weight parts of the silica microbeads are 50-80 parts, and further, the weight parts are 60-70 parts. In some embodiments, the weight part of the negative thermal expansion material is 0 parts, in other embodiments, the weight part of the negative thermal expansion material can be greater than 0 parts and less than or equal to 30 parts, and further can It is more than 0 parts and less than or equal to 20, and more than 0 parts and less than or equal to 10 parts. Silica microbeads themselves have a very low coefficient of thermal expansion, and spherical fillers can improve the fluidity and formability of composite materials. Compounding them with thermoplastic engineering plastics can obtain composite materials with ultra-low thermal expansion coefficients, and By controlling the amount of silica microbeads added, the thermal expansion coefficient can be adjusted within a certain range, and the silica microbeads are readily available, which can greatly reduce the cost of composite material preparation. In the system with silica microbeads as the main functional filler in this embodiment, the addition of a small amount of negative thermal expansion material can further reduce the thermal expansion coefficient.

In the embodiment of the present invention, optionally, the particle size of the silica microbeads is in the range of 1 μm-50 μm, and further, the particle size of the silica microbeads is in the range of 1 μm-20 μm. In the embodiment of the present invention, the silica microspheres may be solid microspheres or hollow microspheres.

Engineering thermoplastics are a class of resins that can be repeatedly heated, softened, cooled and solidified. Their molecular structure is a linear or a small amount of branched non-crosslinked structures. The resins are melted and softened after being pressurized and heated during the molding process, and sheared. Flowing, it can be shaped in the mold, and after cooling and setting, the product of the desired shape can be obtained, which has the advantages of easy molding and repeated molding. Compared with general-purpose plastics, engineering plastics have excellent heat resistance and cold resistance, excellent mechanical properties in a wide temperature range, and are suitable for use as structural materials. In the embodiment of the present invention, the thermoplastic engineering plastics may be of existing conventional types, including but not limited to polyamide, polycarbonate, polyoxymethylene, modified polyphenylene ether, thermoplastic polyester, polyphenylene sulfide, polyether One or more of imide, liquid crystal polymer, polyethersulfone, polyaryletherketone and fluororesin, and the polyphenylene sulfide may specifically be linear polyphenylene sulfide. Among them, selecting engineering plastics with relatively low thermal expansion coefficients can obtain thermoplastic composite materials with lower thermal expansion coefficients.

In the embodiment of the present invention, according to product accuracy requirements, the type and mass ratio of functional fillers and thermoplastic engineering plastics can be designed to actively adjust the expansion coefficient of the composite material to obtain composite materials with different thermal expansion coefficients. Optionally, the weight ratio of the thermoplastic engineering plastic to the functional filler may be 1:0.25-4, and further, the weight ratio of the thermoplastic engineering plastic to the functional filler may be 1 : 1-4, and further, the ratio of the weight fraction of the thermoplastic engineering plastic to the functional filler can be 1: 1-3 or 1: 1.5-2.5.

In an embodiment of the present invention, the coupling agent includes one or more of a silane coupling agent and a titanate coupling agent. The silane coupling agent can be specifically, but not limited to, silane coupling agent KH-550, KH-560, KH-570. The titanate coupling agent may specifically be, but not limited to, titanate coupling CS-101 and titanate coupling agent 109.

In an embodiment of the present invention, the antioxidant includes one or more of hindered phenolic, aromatic amine, phosphite and thioester antioxidants. The other adjuvants include one or more of toughening agents, lubricants, antistatic agents and toners. Specifically, the antioxidant can be one or more selected from the following brands: Antioxidant 1010, Antioxidant 1076, Antioxidant 1098, Antioxidant 626, Antioxidant 300, Antioxidant 1330, Antioxidant 619F or Antioxidant 168. The antistatic agent can be carbon black, and the toner can be carbon black 660R, titanium dioxide ZR-940D, etc.

In the embodiment of the present invention, the lubricant may specifically be, but not limited to, ethylene-propylene copolymer (AC540), solid paraffin, liquid paraffin, zinc stearate, lead stearate, barium stearate, calcium stearate and one or more of pentaerythritol stearate. The toughening agent may specifically be, but not limited to, ethylene-octene copolymer (POE), polypropylene grafted maleic anhydride, maleic anhydride grafted ethylene-1-octene copolymer, butadiene-styrene rubber , chlorinated polyethylene, methacrylate-butadiene-styrene terpolymer (MBS), ethylene-vinyl acetate copolymer (EVA), butyl acrylate-methyl methacrylate copolymer or ethylene-methyl methacrylate One or one of methyl acrylate copolymers.

In the embodiment of the present invention, further optionally, the weight parts of the thermoplastic engineering plastics may be 20-60 parts, and the weight parts of the functional fillers is 40-80 parts; Specifically, the weight part of the plastic can be 20-50 parts, and the weight part of the functional filler is 50-80 parts. In the embodiment of the present invention, the weight portion of the coupling agent may specifically be 1-5 parts or 1-3 parts.

In the embodiment of the present invention, the average thermal expansion coefficient of the thermoplastic composite material in the temperature range of -60°C-350°C is 0-23×10 ^-6 /°C, which can be used as a molding raw material in the field of high-precision plastic parts manufacturing. The thermal expansion coefficient of the composite material mainly depends on the thermal expansion coefficient of both thermoplastic engineering plastics and negative thermal expansion materials. Therefore, for systems with different components, the specific value of the average thermal expansion coefficient is different. Specifically, the average thermal expansion coefficient can be 0-20×10 ^-6 /°C, 0-15×10 ^-6 /°C or 0-10×10 ^-6 /°C, it should be noted that due to the different negative thermal expansion properties of different negative thermal expansion materials at different temperatures, this The thermoplastic composite material in some embodiments of the invention may have a lower average coefficient of thermal expansion in a certain temperature range within the temperature range of -60°C to 350°C.

The thermoplastic composite material provided above in the embodiment of the present invention has an ultra-low thermal expansion coefficient, and the thermal expansion coefficient is adjustable within a certain range, with good heat resistance and high stability. It can be used in the field of precision device molding and can be prepared High-precision plastic parts with high dimensional stability improve the long-term reliability of finished products against temperature shocks and reduce maintenance costs.

Correspondingly, an embodiment of the present invention also provides a method for preparing a thermoplastic composite material, comprising the following steps:

S10. In parts by weight, add 20-80 parts of functional filler and 1-10 parts of coupling agent into a high-speed mixer to mix evenly, and obtain a mixture after drying; the functional filler includes 0-80 parts of negative thermal expansion material and 0-80 parts of silica microbeads;

S20, adding the mixture together with 20-80 parts of thermoplastic engineering plastics, 0.5-1 part of antioxidant, and 0.5-2 parts of other additives into a twin-screw extruder for mixing, extrusion and granulation to obtain thermoplastic The composite material, wherein the total weight of the thermoplastic engineering plastic and the functional filler is 100 parts.

In the embodiment of the present invention, in step S10, the mixing time of the raw materials in the high-speed mixer is 1min-30min, and further can be 5min-20min; the stirring speed of the high-speed mixer can be 500 rpm-1000 rpm, Further it may be 600 rpm - 800 rpm. The drying temperature is 100°C-140°C, specifically 120°C, and the drying time is 2h-3h. By pre-mixing the functional filler (including negative thermal expansion material and silica microbeads) with the coupling agent, the coupling agent can be chemically combined with the surface of the functional filler to obtain a surface with better affinity for the engineering plastic matrix. , so that the functional filler can be better dispersed in the subsequent resin system, so as to obtain thermoplastic composite products with more uniform components, performance and better performance.

In the embodiment of the present invention, in step S10, the linear expansion coefficient of the negative thermal expansion material in the temperature range of -60°C to 350°C is negative in at least one of the three-dimensional directions. In an embodiment of the present invention, the negative thermal expansion material includes at least one of an isotropic negative thermal expansion material and an anisotropic negative thermal expansion material. Specifically, the linear expansion coefficient of the isotropic negative thermal expansion material is negative in all directions; further, the linear expansion coefficient is an equal negative value in all directions, and the isotropic negative thermal expansion material has a negative value. It exhibits consistent inflation behavior in all directions. The anisotropic negative thermal expansion material means that the coefficient of linear expansion is negative in some directions, and positive or zero in other directions, thus showing inconsistent expansion behavior in all directions. In the embodiment of the present invention, the negative thermal expansion material is preferably an isotropic negative thermal expansion material. Since the expansion behavior in all directions is consistent, the thermoplastic composite material can have a more uniform and stable thermal stress, thereby further making the thermoplastic composite material. parts with higher stability, fatigue life and thermal shock resistance.

Specifically, in the embodiment of the present invention, the negative thermal expansion material can be selected from pyrophosphates, pyrotungstates, tungstates, manganese nitrogen compounds, cordierites, β-eucryptites, pomegranates One or more of stone negative thermal expansion materials. More specifically, the pyrophosphate-based negative thermal expansion material includes ZrP ₂ O ₇ ; the pyrotungstate-based negative thermal expansion material includes ZrW ₂ O ₈ ; the tungstate-based negative thermal expansion material includes Al ₂ W ₃ O ₁₂ , Y ₂ W ₃ O ₁₂ , Sc ₂ W ₃ O ₁₂ ; the manganese-nitrogen compound-based negative thermal expansion material includes Mn ₃ AN, and A in the Mn ₃ AN is Zn, Ga, Cu, Fe, and Ge. One or more, wherein Mn can be partially substituted by other elements (such as Fe, etc.); the cordierite-based negative thermal expansion material includes Mg ₂ Al ₄ Si ₅ O ₁₈ ; the β-eucryptite-based negative thermal expansion material includes LiAl ₂ Si ₂ O ₈ ; the garnet-based negative thermal expansion materials include NaZr ₂ (PO ₄ ) ₃ and KZr ₂ (PO ₄ ) ₃ . The above specific negative thermal expansion materials are only examples, and the present invention is not limited to the above listed negative thermal expansion materials.

In an embodiment of the present invention, the coupling agent includes one or more of a silane coupling agent and a titanate coupling agent.

In the embodiment of the present invention, in step S20, the screw speed of the twin-screw extruder is 150-300 rpm, and the extrusion temperature is 180-380°C. Further, the rotational speed is 200-300 rpm. The specific extrusion temperature can be determined according to the selected resin type and the relative proportion of the negative thermal expansion material added to achieve the purpose of fully plasticizing and mixing. , 350℃, 380℃.

In the embodiment of the present invention, the engineering resin may be of existing conventional types, including but not limited to polyamide, polycarbonate, polyoxymethylene, modified polyphenylene ether, thermoplastic polyester, polyphenylene sulfide, polyether amide One or more of imine, liquid crystal polymer, polyethersulfone, polyaryletherketone, and fluororesin. Specifically, the thermal expansion coefficient, formability and mechanical properties can be comprehensively selected according to requirements. The thermoplastic engineering plastic generally needs to be pre-dried and then mixed with other raw materials.

In an embodiment of the present invention, the weight portion of the negative thermal expansion material is 20-80 parts, and the weight portion of the silica microbeads is 0-20 parts. Further, the weight part of the negative thermal expansion material is 30-70 parts, further 45-70 parts, 50-70 parts. Wherein, in some embodiments, the weight part of the silica microbeads is 0 parts, and in other embodiments, the weight part of the silica microbeads is greater than 0 parts and less than or equal to 10 parts . Further, the parts by weight of the silica microbeads are 0-10 parts.

In another embodiment of the present invention, the weight part of the silica microbeads is 40-80 parts, and the weight part of the negative thermal expansion material is 0-30 parts. Further, the weight parts of the silica microbeads are 50-80 parts, further 60-70 parts. In some embodiments, the weight part of the negative thermal expansion material is 0 parts, and in other embodiments, the weight part of the negative thermal expansion material is greater than 0 parts and less than or equal to 30 parts.

In the embodiment of the present invention, optionally, the particle size of the silica microbeads is in the range of 1 μm-50 μm, further, the particle size of the silica microbeads is in the range of 10 μm-30 μm, and further, The particle size of the silica microbeads is in the range of 10 μm-20 μm. In the embodiment of the present invention, the silica microspheres may be solid microspheres or hollow microspheres.

In the embodiment of the present invention, according to product accuracy requirements, the type and mass ratio of functional fillers and engineering plastics can be designed to actively adjust the expansion coefficient of the composite material to obtain thermoplastic composite materials with different thermal expansion coefficients. Considering the molding properties, mechanical properties, thermal expansion coefficient, etc., optionally, the weight ratio of the thermoplastic engineering plastic to the functional filler can be 1:0.25-4. Further, the thermoplastic engineering plastic and the The weight ratio of the functional filler may be 1:1-3, and further, the weight ratio of the thermoplastic engineering plastic to the functional filler may be 1:1.5-2.5.

In an embodiment of the present invention, the coupling agent includes one or more of a silane coupling agent and a titanate coupling agent. The antioxidants include one or more of hindered phenols, aromatic amines, phosphites and thioesters. The other adjuvants include one or more of toughening agents, lubricants, antistatic agents and toners.

In the embodiment of the present invention, further optionally, the weight parts of the thermoplastic engineering plastics may be 20-60 parts, and the weight parts of the functional fillers is 40-80 parts; Specifically, the weight part of the plastic can be 20-50 parts, and the weight part of the functional filler is 50-80 parts. In the embodiment of the present invention, the weight portion of the coupling agent may specifically be 1-5 parts or 1-3 parts.

In the embodiment of the present invention, the average thermal expansion coefficient of the prepared thermoplastic composite material in the temperature range of -60°C to 350°C is 0-23×10 ^-6 /°C.

The preparation method of the thermoplastic composite material provided by the embodiment of the present invention has a simple process and is suitable for large-scale industrial production.

The thermoplastic composite material provided above in the embodiment of the present invention has an ultra-low thermal expansion coefficient, and the thermal expansion coefficient is adjustable within a certain range, with good heat resistance and high stability, and is used for optical communication and 5G equipment precision device molding In the field, high-precision plastic parts with high dimensional stability can be prepared, which can improve the reliability of long-term temperature shock resistance of finished products and reduce maintenance costs.

The embodiments of the present invention will be further described below by dividing into multiple embodiments.

Example 1

A thermoplastic composite material comprising the following components in parts by weight: 30 parts of linear polyphenylene sulfide, 60 parts of pyrotungstate (ZrW ₂ O ₈ ), 10 parts of SiO ₂ microbeads, silane coupling 1.5 parts of joint agent, 0.5 part of antioxidant, and 1 part of other additives.

The preparation method of the thermoplastic composite material of the present embodiment comprises the following steps:

S10. Add pyrotungstate (ZrW ₂ O ₈ ), SiO ₂ microbeads and silane coupling agent into a high-speed mixer, mix at a stirring speed of 800 rpm for 20 minutes, and then dry at 120° C. for 2 hours to obtain Mixture;

S20. After pre-drying the polyphenylene sulfide, add it to the twin-screw extruder together with the above-mentioned mixture, antioxidant and processing aid for mixing and dispersing. The screw speed of the twin-screw extruder is 200 rpm. The temperature is 320° C., and plastic pellets are obtained after extrusion and cooling, that is, the thermoplastic polyphenylene sulfide composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in Example 1 of the present invention in the temperature range of -60°C to 350°C is in the range of 0-23×10 ^-6 /°C, specifically, about 11.3×10 ^-6 /°C, And has an isotropic negative thermal expansion behavior, which is because ZrW ₂ O ₈ has a negative thermal expansion coefficient of -8.8×10 ^-6 /℃ in a wide temperature range (0.3K-1050K), and the shrinkage is consistent in all directions. The thermoplastic polyphenylene sulfide composite material of this embodiment also has the characteristics of good heat resistance, high mechanical strength and excellent flame retardancy.

Example 2

A thermoplastic composite material, the composite material comprises the following components in parts by weight: 30 parts of linear polyphenylene sulfide, 60 parts of pyrophosphate (ZrP ₂ O ₇ ), 10 parts of SiO ₂ microbeads, and silane coupling 1.5 parts of antioxidants, 0.5 parts of antioxidants, and 1 part of other additives.

The preparation method of the thermoplastic composite material of the present embodiment comprises the following steps:

S10. Add pyrophosphate (ZrP ₂ O ₇ ), SiO ₂ microbeads and silane coupling agent into a high-speed mixer, mix at a stirring speed of 600 rpm for 30 minutes, and then dry at 120° C. for 3 hours to obtain a mixed solution material;

S20. After pre-drying the polyphenylene sulfide, add it to the twin-screw extruder together with the above-mentioned mixture, antioxidant and processing aid for mixing and dispersing. The screw speed of the twin-screw extruder is 300 rev/min. The temperature is 320° C., and plastic pellets are obtained after extrusion and cooling, that is, the thermoplastic polyphenylene sulfide composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in Example 1 of the present invention in the temperature range of -60°C-350°C is in the range of 0-23×10 ^-6 /°C, specifically, the average thermal expansion coefficient in the temperature range of 100°C-350°C The average thermal expansion coefficient is about 10.0×10 ^-6 /°C, and it has an isotropic negative thermal expansion behavior. This is due to the negative thermal expansion coefficient of ZrP ₂ O ₇ -10.8 × 10 ^-6 /°C over a wide temperature range of 373-773 K.

Example 3

A thermoplastic composite material comprising the following components in parts by weight: 36 parts of linear polyphenylene sulfide, 44 parts of nitrogen-manganese magnetic compound ((Mn _0.96 Fe _0.04 ) ₃ (Zn _0.5 Ge _0.5 )N) , 20 parts of SiO ₂ microbeads, 3 parts of silane coupling agent, 0.5 part of antioxidant, and 1 part of other additives.

The preparation method of the thermoplastic composite material of the present embodiment comprises the following steps:

S10. Add nitrogen-manganese magnetic compound ((Mn _0.96 Fe _0.04 ) ₃ (Zn _0.5 Ge _0.5 )N), SiO ₂ microbeads and silane coupling agent into a high-speed mixer, and mix at a stirring speed of 700 rpm for 25 minutes After drying at 130°C for 2h, the mixture was obtained;

S20. After pre-drying the polyphenylene sulfide, add it to the twin-screw extruder together with the above-mentioned mixture, antioxidant and processing aid for mixing and dispersing. The screw speed of the twin-screw extruder is 150 rev/min. The temperature is 320° C., and plastic pellets are obtained after extrusion and cooling, that is, the thermoplastic polyphenylene sulfide composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in Example 3 of the present invention in the temperature range of -60°C-350°C is in the range of 0-23×10 ^-6 /°C, specifically, the average thermal expansion coefficient in the temperature range of 43°C-113°C The average thermal expansion coefficient is about 10.8×10 ^-6 /°C, and it has an isotropic negative thermal expansion behavior. This is because the thermal expansion coefficient of (Mn _0.96 Fe _0.04 ) ₃ (Zn _0.5 Ge _0.5 )N reaches -25×10 ^-6 /°C in 316K-386K, and the negative expansion effect is remarkable. In this embodiment, the thermal expansion coefficient of the thermoplastic polyphenylene sulfide composite material of this embodiment can be regulated by changing the metal ratio in the nitrogen-manganese compound. In addition, since (Mn _0.96 Fe _0.04 ) ₃ (Zn _0.5 Ge _0.5 )N has good metallicity and mechanical strength, the thermoplastic polyphenylene sulfide composite material of this embodiment has high mechanical strength and good electrical and thermal conductivity.

Example 4

A thermoplastic composite material, the composite material comprises the following components in parts by weight: 25 parts of polyetherimide (PEI), 60 parts of scandium tungstate (Sc ₂ W ₃ O ₁₂ ) powder, SiO ₂ micro 15 parts of beads, 2.5 parts of titanate coupling agent, 0.5 parts of antioxidant, 2 parts of other additives.

The preparation method of the thermoplastic composite material of the present embodiment comprises the following steps:

S10, adding scandium tungstate powder, SiO ₂ microbeads and titanate coupling agent into a high-speed mixer, mixing at a stirring speed of 800 rpm for 25 minutes, and drying at 120° C. for 2 hours to obtain a mixture;

S20, the polyetherimide is pre-dried and added to the twin-screw extruder together with the above-mentioned compound, antioxidant and processing aid for mixing and dispersion, and the screw speed of the twin-screw extruder is 250 rev/min, The processing temperature is 350° C., and plastic pellets are obtained after extrusion and cooling, that is, the thermoplastic polyetherimide composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in Example 4 of the present invention in the temperature range of -60°C-350°C is in the range of 0-23×10 ^-6 /°C, specifically, in the temperature range of -60°C-177°C The average thermal expansion coefficient is about 14.5×10 ^-6 /℃. The thermal expansion coefficient of Sc ₂ W ₃ O ₁₂ powder in 10K-450K is -2.2×10 ^-6 /℃.

Example 5

A thermoplastic composite material, the composite material comprises the following components in parts by weight: 35 parts of polyetherimide (PEI), 50 parts of β-eucryptite LiAl ₂ Si ₂ O ₈ powder, SiO ₂ micro 15 parts of beads, 2 parts of titanate coupling agent, 0.5 part of antioxidant, 1.5 part of other additives.

The preparation method of the thermoplastic composite material of the present embodiment comprises the following steps:

S10. Add β-eucryptite LiAl ₂ Si ₂ O ₈ powder, SiO ₂ microbeads and titanate coupling agent into a high-speed mixer, mix at a stirring speed of 800 rpm for 25 minutes, and then heat at 120° C. Dry for 2h to obtain the mixture;

S20, adding the polyetherimide to the twin-screw extruder together with the above-mentioned compound, antioxidant and processing aid after pre-drying, mixing and dispersing, and the screw speed of the twin-screw extruder is 200 rpm, The processing temperature is 350° C., and plastic pellets are obtained after extrusion and cooling, that is, the thermoplastic polyetherimide composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in Example 5 of the present invention in the temperature range of -60°C-350°C is in the range of 0-23×10 ^-6 /°C, specifically, the average thermal expansion coefficient in the temperature range of 25°C-350°C The average thermal expansion coefficient is about 14.5×10 ^-6 /°C. The thermal expansion coefficient of β-eucryptite LiAl ₂ Si ₂ O ₈ in the temperature range of 298K-1273K is -6.2×10 ^-6 /℃.

Example 6

A thermoplastic composite material comprising the following components in parts by weight: 40 parts of liquid crystal polymer (LCP), 60 parts of ZrW ₂ O ₈ powder, 2 parts of silane coupling agent, and 0.5 part of antioxidant , 0.5 part of processing aid.

The preparation method of the liquid crystal polymer composite material in this embodiment includes the following steps:

S10, adding the ZrW ₂ O ₈ powder and the silane coupling agent into a high-speed mixer, mixing at a stirring speed of 800 rpm for 25 minutes, and drying at 120° C. for 2 hours to obtain a mixture;

S20. Add the liquid crystal polymer together with the above-mentioned mixture, antioxidant and processing aid into a twin-screw extruder for mixing and dispersing. The screw speed of the twin-screw extruder is 200 rpm and the processing temperature is 200° C. , plastic pellets are obtained after extrusion and cooling, that is, the liquid crystal polymer composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in Example 6 of the present invention in the temperature range of -60°C to 350°C is in the range of 0-23×10 ^-6 /°C. Specifically, the average linear thermal expansion coefficient in the vertical flow direction is about It is 18.7×10 ^-6 /℃, which can improve the dimensional accuracy of LCP composites in the vertical flow direction.

Example 7

A thermoplastic composite material, the composite material comprises the following components in parts by weight: 30 parts of linear polyphenylene sulfide, 70 parts of SiO ₂ microbeads, 1 part of silane coupling agent, 0.4 part of antioxidant, and other auxiliary materials. 1 dose.

The preparation method of the thermoplastic composite material of the present embodiment comprises the following steps:

S10, adding the SiO ₂ microbeads and the silane coupling agent into a high-speed mixer, mixing at a stirring speed of 600 rpm for 20 minutes, and drying at 120° C. for 2 hours to obtain a mixture;

S20. After pre-drying the polyphenylene sulfide, add it to the twin-screw extruder together with the above-mentioned mixture, antioxidant and processing aid for mixing and dispersing. The screw speed of the twin-screw extruder is 200 rpm. The temperature is 320° C., and plastic pellets are obtained after extrusion and cooling, that is, the thermoplastic polyphenylene sulfide composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in this example in the temperature range of -60°C-350°C is in the range of 0-23×10 ^-6 /°C, specifically, about 18×10 ^-6 /°C, and has Isotropic negative thermal expansion behavior. The low thermal expansion coefficient thermoplastic polyphenylene sulfide composite material of this example has good fluidity and formability due to the lubricating effect of SiO ₂ microbeads.

Example 8

A thermoplastic composite material comprising the following components in parts by weight: 40 parts of linear polyphenylene sulfide, 40 parts of SiO ₂ microbeads, and 20 parts of β-eucryptite LiAl ₂ Si ₂ O ₈ powder , 1.5 parts of silane coupling agent, 0.4 part of antioxidant, 1 part of other additives.

The preparation method of the thermoplastic composite material of the present embodiment comprises the following steps:

S10. Add SiO ₂ microbeads, β-eucryptite LiAl ₂ Si ₂ O ₈ powder and silane coupling agent into a high-speed mixer, mix at a stirring speed of 600 rpm for 20 minutes, and then dry at 120° C. 2h, the mixture was obtained;

S20. After pre-drying the polyphenylene sulfide, add it to the twin-screw extruder together with the above-mentioned mixture, antioxidant and processing aid for mixing and dispersing. The screw speed of the twin-screw extruder is 200 rpm. The temperature is 320° C., and plastic pellets are obtained after extrusion and cooling, that is, the thermoplastic polyphenylene sulfide composite material of this embodiment.

The average thermal expansion coefficient of the thermoplastic composite material obtained in this example in the temperature range of -60°C-350°C is in the range of 0-23×10 ^-6 /°C, specifically, about 20×10 ^-6 /°C, and has Isotropic negative thermal expansion behavior. The filler in this example is mainly composed of SiO ₂ microbeads and compounded with β-eucryptite to obtain a low thermal expansion coefficient composite material with good fluidity.

Using the thermoplastic composite material prepared above in the embodiment of the present invention as a raw material, high-precision plastic parts with different structures can be prepared by means of injection molding or the like. Specifically, the high-precision plastic parts may include antenna brackets/shells, diffraction gratings, optical fiber connectors, mobile phone precision structural parts, etc., and the composite materials provided by the embodiments of the present invention are used to prepare the components, which can greatly improve the thermal shock resistance of the devices. performance and long-term operational reliability.

Claims (20)

1. The thermoplastic composite material is characterized by comprising the following components in parts by weight:

the functional filler comprises 0-80 parts of negative thermal expansion material and 0-80 parts of silicon dioxide microbeads, and the total weight of the thermoplastic engineering plastic and the functional filler is 100 parts.

2. The composite material of claim 1, wherein the negative thermal expansion material is 20 to 80 parts by weight, and the silica micro beads are 0 to 20 parts by weight.

3. The composite material of claim 2, wherein the negative thermal expansion material is present in an amount of 30 to 70 parts by weight.

4. The composite material of claim 1, wherein the silica micro beads are present in an amount of 40 to 80 parts by weight, and the negative thermal expansion material is present in an amount of 0 to 30 parts by weight.

5. The composite material of claim 4, wherein the silica microbeads range from 50 to 80 parts by weight.

6. The composite material according to any one of claims 1 to 5, wherein the ratio of parts by weight of the engineering thermoplastic to the functional filler is from 1:1 to 4.

7. The composite material of claim 1, wherein the negative thermal expansion material has an average linear expansion coefficient in a temperature range of-60 ℃ to 350 ℃ that is negative in at least one of three dimensions.

8. The composite material of any one of claims 1-7, wherein the negative thermal expansion material comprises one or more of pyrophosphates, pyrotungstates, tungstates, manganese nitrides, cordionites, β -eucryptites, garnet-like negative thermal expansion materials.

9. The composite material of claim 8, wherein the pyrophosphate-based negative thermal expansion material comprises ZrP ₂O₇The pyrotungstate negative thermal expansion material comprises ZrW₂O₈The tungstate negative thermal expansion material comprises Al₂W₃O₁₂、Y₂W₃O₁₂、Sc₂W₃O₁₂The manganese nitrogen compound negative thermal expansion material comprises Mn₃AN, said Mn₃A in AN is one or more of Zn, Ga, Cu, Fe and Ge, and the cordierite negative thermal expansion material comprises Mg₂Al₄Si₅O₁₈The beta-eucryptite negative thermal expansion material comprises LiAl₂Si₂O₈The garnet negative thermal expansion material comprises NaZr₂(PO₄)₃、KZr₂(PO₄)₃。

10. The composite material of claim 1, wherein the silica microbeads range in size from 1 μ ι η to 50 μ ι η, the silica microbeads being either solid or hollow.

11. The composite material of claim 1, wherein the engineering thermoplastic comprises one or more of a polyamide, a polycarbonate, a polyoxymethylene, a modified polyphenylene ether, a thermoplastic polyester, a polyphenylene sulfide, a polyetherimide, a liquid crystal polymer, a polyethersulfone, a polyaryletherketone, and a fluororesin.

12. The composite material of claim 1, wherein the coupling agent comprises one or more of a silane coupling agent, a titanate coupling agent.

13. The composite material of claim 1, wherein the antioxidant comprises one or more of hindered phenolic, aromatic amine, phosphite, and thioester antioxidants.

14. The composite of claim 1, wherein the other additives include one or more of a toughening agent, a lubricant, an antistatic agent, and a toner.

15. The composite material of claim 1, wherein the thermoplastic composite material has an average coefficient of thermal expansion of 0 to 23 x 10 over a temperature range of-60 ℃ to 350 ℃^-6/℃。

16. A method of making a thermoplastic composite, comprising the steps of:

according to the parts by weight, 20-80 parts of functional filler and 1-10 parts of coupling agent are added into a high-speed mixer to be uniformly mixed, and the mixture is obtained after drying; the functional filler comprises 0-80 parts of negative thermal expansion material and 0-80 parts of silicon dioxide micro-beads;

and adding the mixture, 20-80 parts of thermoplastic engineering plastic, 0.5-1 part of antioxidant and 0.5-2 parts of other auxiliary agents into a double-screw extruder together for mixing, and extruding and granulating to obtain the thermoplastic composite material, wherein the total weight part of the thermoplastic engineering plastic and the functional filler is 100 parts.

17. The method of claim 16, wherein the twin-screw extruder has a screw speed of 150-.

18. The method of claim 16, wherein the mixing time is from 1min to 30 min.

19. A high precision plastic part characterized in that it is produced using a thermoplastic composite material according to any one of claims 1 to 15.

20. The high-precision plastic part of claim 19, wherein the high-precision plastic part comprises an antenna mount, an antenna housing, a diffraction grating, a fiber optic connector, or a cell phone precision structure.