A low-warpage polyamide modified material, mining truck oil cylinder guide ring and preparation process thereof

Abstract

The present invention relates to a low-warpage polyamide modified material, comprising the following components in parts by weight: 30 to 85 parts of base resin, 5 to 40 parts of a first reinforcing component, 10 to 30 parts of a second reinforcing component, 0.1 to 2 parts of a lubricant, 0.1 to 1 part of an antioxidant, and 1 to 10 parts of an anti-wear agent, wherein the first reinforcing component is an alkali-free flat glass fiber modified by a coupling agent; the second reinforcing component is one or more of wollastonite, calcium carbonate, mica powder, talcum powder, and glass microbeads. The present invention not only enhances the strength of the material by compounding inorganic mineral powder with flat glass fiber, but also solves the problem of warpage deformation of high-component glass fiber reinforced materials after injection molding; the flat glass fiber not only enhances the lateral strength, but also enhances the longitudinal strength, and has better low warpage and compressive strength. The guide ring of the oil cylinder of a mining truck produced with the material has no floating fibers, low gloss, and small deformation.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-warping guide ring materials and guide ring forming processing of a mining truck oil cylinder sealing system, and particularly relates to a low-warping polyamide modified material, a mining truck oil cylinder guide ring and a preparation process thereof. Background Art

[0002] A mining truck is a heavy-duty dump truck used in open-pit mines to complete rock and earth stripping and ore transportation tasks. Its working characteristics are short haul distances and heavy loads. It travels back and forth between the mining site and the unloading site, making it an indispensable piece of machinery for modern mining companies. The working conditions of mining trucks are usually very harsh. Uphill roads, wet waterways, potholes, inclines and other road conditions are very common. In addition, the trucks need to work closely with other mining equipment and work continuously for many days in a single operation. In this case, the stable and reliable operation of the mining trucks is crucial. The cylinder is an important component of the mining dump truck, including the suspension cylinder, lifting cylinder, steering cylinder, etc. The performance of the cylinder directly affects the smoothness, passability and comfort of the dump truck.

[0003] In each oil cylinder of a mining truck, the guide element (also called a guide ring or support ring) is a vital component. It can not only rub against the piston rod and the cylinder barrel, play a guiding role and ensure smooth reciprocating operation, but also resist lateral loads, isolate the piston rod and the guide sleeve, isolate the piston and the cylinder barrel, prevent the "iron-to-iron" phenomenon, and protect the cylinder body and the piston or piston rod, thereby ensuring the stability and long life of the overall sealing system.

[0004] Guide rings for mining truck cylinders are typically large and come in a wide variety of sizes. This requires the guide component material to be high-strength, compressive, wear-resistant, and dimensionally stable. Using traditional injection molding machines to mold these large guide rings would require large-scale injection molding equipment of 2000 tons or more, resulting in extremely high investment costs and limited production flexibility. Using turning as a production process would also result in significant material loss, necessitating a suitable molding process.

[0005] Products made from materials with high fiber filling often have warping and deformation issues, which not only affects the appearance and assembly of the guide ring, but also has a significant impact on the friction and wear of the wire ring, thereby affecting the service life of the product. Summary of the Invention

[0006] The purpose of the present invention is to provide a low-warpage polyamide modified material, a mining truck cylinder guide ring and its preparation process, which can solve the current problems of insufficient strength, severe warping and deformation of mining truck cylinder guide elements, large investment in traditional molding equipment, and complex molding.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A low-warpage polyamide modified material comprises the following components in parts by weight:

[0009] The composition comprises the following components in parts by weight:

[0010] Base resin: 30-85 parts, first reinforcing component 5-40 parts; second reinforcing component 10-30 parts, lubricant 0.1-2 parts, antioxidant 0.1-1 parts, wear-resistant agent 1-10 parts,

[0011] Preferably, the matrix resin is PA engineering plastic, and the PA engineering plastic is one or more of PA6, PA66, PA66 / 6, and high-temperature nylon.

[0012] Preferably, the first reinforcing component is an alkali-free flat glass fiber modified with a coupling agent, and the cross-section of the first reinforcing component is elliptical, with a ratio of the major axis to the minor axis ranging from 2:1 to 6:1;

[0013] Preferably, the second reinforcing component is mineral powder; the mineral powder is one or more of wollastonite, calcium carbonate, mica powder, talc powder, and glass beads.

[0014] Preferably, the lubricant is one or more of fatty acid salt, erucamide, silicone powder, and EBS wax.

[0015] Preferably, the antioxidant is a hindered phenol antioxidant, and the hindered phenol antioxidant is one or more of 1010 antioxidant, 168 antioxidant, 2246 antioxidant, 245 antioxidant, and 1098 antioxidant.

[0016] Preferably, the wear-resistant additive is one or more of PTFE, MoS2, and graphite.

[0017] Another aspect of the present invention provides a process for preparing a low-warpage polyamide modified material, comprising the following steps:

[0018] 1) mixing the lubricant, antioxidant and anti-wear agent in a high-speed mixer to obtain a powdery mixture;

[0019] 2) The matrix resin, the second reinforcement component, and the powdered mixture are weighed separately and fed into a twin-screw extruder through a main feed port for melt blending;

[0020] 3) Weighing the first reinforcement component and feeding it into the twin-screw extruder through the side feed port;

[0021] 4) The material is melted, sheared, and plasticized in a twin-screw extruder, and granular material is extruded to obtain modified granular material, wherein the speed of the twin-screw extruder is: 300-420 rpm, and the temperature is: 220℃-270℃.

[0022] Another aspect of the present invention provides a guide ring for a mining truck cylinder, wherein the material of the guide ring for the mining truck cylinder is the low-warpage polyamide modified material described above.

[0023] Another aspect of the present invention provides a process for preparing a guide ring of a mining truck oil cylinder, comprising the following steps:

[0024] 1) Dry the modified pellets at 110°C for 4 hours;

[0025] 2) Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to maintain the material temperature at 250°C;

[0026] 3) The molten material is injected into the mold through the die, wherein the injection pressure of the injection machine is 20-30 MPa, the mold closing pressure is 25-35 MPa, the mold temperature is 80°C-95°C, and the barrel is extruded after cooling and demoulding; then the barrel is placed in 90°C-100°C water and soaked for 2-3 hours;

[0027] 4) Turning the soaked tube material into a guide ring product;

[0028] 5) Fix the processed product on a supporting fixture and place it under the condition of 100℃~125℃ for 2~4h;

[0029] 6) Process the opening as needed.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1) The first reinforcement component and the second reinforcement component are inorganic mineral powder and flat glass fiber respectively. The compounding of inorganic mineral powder and flat glass fiber not only enhances the strength of the material, but also solves the problem of warping deformation of high-component glass fiber reinforced materials after injection molding;

[0032] 2) Flat glass fiber not only enhances the lateral strength, but also the longitudinal strength, and has a better reinforcement effect than round glass;

[0033] 3) Excellent appearance;

[0034] 4) The injection-turning-forming-opening processing method is adopted, which has the characteristics of low one-time investment cost of equipment and flexible and changeable production compared with the traditional injection molding process. DETAILED DESCRIPTION

[0035] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0036] The low-warpage polyamide modified material of the present invention comprises the following components in parts by weight:

[0037] Base resin: 30-85 parts, first reinforcing component 5-40 parts; second reinforcing component 10-30 parts, lubricant 0.1-2 parts, antioxidant 0.1-1 parts, wear-resistant agent 1-10 parts,

[0038] Specifically, the matrix resin is PA engineering plastic, and the PA engineering plastic is one or more of PA6, PA66, PA66 / 6, and high-temperature nylon.

[0039] Specifically, the first reinforcing component is an alkali-free flat glass fiber modified with a coupling agent, and the cross-section of the first reinforcing component is elliptical, with a ratio of the major axis to the minor axis ranging from 2:1 to 6:1;

[0040] Specifically, the second reinforcing component is mineral powder, and the mineral powder is one or more of wollastonite, calcium carbonate, mica powder, talc powder, and glass beads.

[0041] Specifically, the lubricant is one or more of fatty acid salt, erucamide, silicone powder, and EBS wax.

[0042] Specifically, the antioxidant is a hindered phenol antioxidant, and the hindered phenol antioxidant is one or more of 1010 antioxidant, 168 antioxidant, 2246 antioxidant, 245 antioxidant, and 1098 antioxidant.

[0043] Specifically, the wear-resistant additive is one or more of PTFE, MoS2, and graphite.

[0044] The specific preparation process includes the following steps:

[0045] 1) mixing the lubricant, antioxidant and anti-wear agent in a high-speed mixer to obtain a powdery mixture;

[0046] 2) The matrix resin, the second reinforcing component, and the powdered mixture in step 1) are weighed separately and fed into a twin-screw extruder through a main feed port for melt blending;

[0047] 3) Weighing the first reinforcement component and feeding it into the twin-screw extruder through the side feed port;

[0048] 4) The material is melted, sheared, and plasticized in a twin-screw extruder, and pellets are extruded to obtain finished modified pellets. The speed of the twin-screw extruder is 300-420 rpm, the temperature is 220° C.-270° C., and the screw length-diameter ratio is 40:1.

[0049] Another embodiment of the present invention further discloses a mining truck oil cylinder guide ring, which is applied to the oil cylinder of a mining truck, wherein the material of the mining truck oil cylinder guide ring is the low-warpage polyamide modified material described above.

[0050] In another embodiment of the present invention, a preparation process of the above-mentioned mining truck cylinder guide ring is also provided, comprising the following steps:

[0051] 1) Dry the modified pellets at 110°C for 4 hours;

[0052] 2) adding the modified pellets dried in step 1) into the barrel of an injection machine, heating and melting them, and transferring them to a storage barrel equipped with a heat preservation device, maintaining the material temperature at 250° C.;

[0053] 3) The molten material is injected into the mold through the die, wherein the temperature zones of the injection machine are: 220°C, 230°C, 230°C, 230°C, 240°C, 245°C, 245°C, 250°C, 250°C, the injection pressure is 20-30MPa, the mold closing pressure is 25-35MPa, the mold temperature is 80°C-95°C, and after cooling and demoulding, the barrel is extruded, and then the barrel is soaked in 90°C-100°C water for 2-3h;

[0054] 4) Turn the barrel into guide ring products of specific size according to the drawing;

[0055] 5) Fix the processed product on a supporting fixture and place it under the condition of 100℃~125℃ for 2~4h;

[0056] 6) Process the opening as needed.

[0057] The present invention will be further described below with reference to specific examples.

[0058] During specific implementation, in the present invention, preferably, the first reinforcing component adopts PA6 from Yangquan Coal Group Taiyuan Chemical New Materials Co., Ltd., with a viscosity of 2.2 and a melting point of 210°C to 230°C; the flat glass fiber and cylindrical glass fiber are chopped glass fibers from Taishan Glass Fiber Co., Ltd., with a length of 6 mm and an aspect ratio of 6:1 for the flat glass fiber; the second reinforcing component adopts glass microbeads from Shanxi Hainuo Technology Co., Ltd., with a particle size of 15 to 125 μm; the lubricant is calcium stearate; and the wear-resistant agent is MoS2.

[0059] Example 1

[0060] A guide ring for a mining truck oil cylinder, comprising the following components in parts by weight: 55 parts of PA6 material, 30 parts of flat glass fiber, 10 parts of glass microbeads, 0.3 parts of an antioxidant, 0.6 parts of a lubricant, and 5 parts of a MoS2 wear-resistant agent;

[0061] The specific preparation method is prepared according to the following steps:

[0062] The lubricant, MoS2, antioxidant, and glass microspheres were blended at high speed in a vertical mixer for 10 minutes and then added from the main feed port of a twin-screw extruder.

[0063] Add PA6 material from the twin-screw extruder through the main feed port;

[0064] Add the chopped flat glass fibers through the dedicated side feed port of the twin-screw extruder;

[0065] The above materials are melted, extruded, cooled and pelletized by a twin-screw extruder to obtain modified pellets;

[0066] The modified pellets were then dried at 110 °C for 4 h;

[0067] Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to maintain the material temperature at 250°C;

[0068] The molten material is poured into the mold through the die, cooled and demoulded, and then extruded into a cylinder; the cylinder is then immersed in 95°C water for 2.5 hours;

[0069] The soaked tube material is turned into guide ring products of specific size according to the drawing;

[0070] Fix the processed product on a supporting fixture and place it under 120℃ for 3 hours;

[0071] Machine the opening as needed.

[0072] Example 2

[0073] A guide ring for a mining truck oil cylinder, comprising the following components in parts by weight: 55 parts of PA6 material, 20 parts of flat glass fiber, 20 parts of glass microbeads, 0.3 parts of an antioxidant, 0.6 parts of a lubricant, and 5 parts of a MoS2 wear-resistant agent;

[0074] The specific preparation method is prepared according to the following steps:

[0075] The lubricant, MoS2, antioxidant, and glass microspheres were blended at high speed in a vertical mixer for 10 minutes and then added from the main feed port of a twin-screw extruder.

[0076] Add PA6 material from the twin-screw extruder through the main feed port;

[0077] Add the chopped flat glass fibers through the dedicated side feed port of the twin-screw extruder;

[0078] The above materials are melted, extruded, cooled and pelletized through a twin-screw extruder to obtain modified pellets.

[0079] The modified pellets were then dried at 110 °C for 4 h;

[0080] Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to maintain the material temperature at 250°C;

[0081] The molten material is poured into the mold through the die, cooled and demoulded, and then extruded into a cylinder; the cylinder is then immersed in 95°C water for 2.5 hours;

[0082] The soaked tube material is turned into guide ring products of specific size according to the drawing;

[0083] Fix the processed product on a supporting fixture and place it under 120℃ for 3 hours;

[0084] Machine the opening as needed.

[0085] Example 3

[0086] A guide ring for a mining truck oil cylinder, comprising the following components in parts by weight: 55 parts of PA6 material, 10 parts of flat glass fiber, 30 parts of glass microbeads, 0.3 parts of an antioxidant, 0.6 parts of a lubricant, and 5 parts of a MoS2 wear-resistant agent;

[0087] The specific preparation method is prepared according to the following steps:

[0088] The lubricant, MoS2, antioxidant, and glass microspheres were blended at high speed in a vertical mixer for 10 minutes and then added from the main feed port of a twin-screw extruder.

[0089] Add PA6 material from the twin-screw extruder through the main feed port;

[0090] Add the chopped flat glass fibers through the dedicated side feed port of the twin-screw extruder;

[0091] The above materials are melted, extruded, cooled and pelletized through a twin-screw extruder to obtain modified pellets.

[0092] The modified pellets were then dried at 110 °C for 4 h;

[0093] Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to maintain the material temperature at 250°C;

[0094] The molten material is poured into the mold through the die, cooled and demoulded, and then extruded into a cylinder; the cylinder is then immersed in 95°C water for 2.5 hours;

[0095] The soaked tube material is turned into guide ring products of specific size according to the drawing;

[0096] Fix the processed product on a supporting fixture and place it under 120℃ for 3 hours;

[0097] Machine the opening as needed.

[0098] Comparative Example 1

[0099] Weigh 55 parts of PA6 material, 30 parts of cylindrical glass fiber, 10 parts of glass beads, 0.3 parts of antioxidant, 0.6 parts of lubricant, and 5 parts of MoS2 wear-resistant agent according to the weight ratio;

[0100] The lubricant, MoS2, antioxidant, and glass microspheres were blended at high speed in a vertical mixer for 10 minutes and then added from the main feed port of a twin-screw extruder.

[0101] Add PA6 material from the twin-screw extruder through the main feed port;

[0102] Add chopped cylindrical glass fibers through the dedicated side feed port of the twin-screw extruder;

[0103] The above materials are melted, extruded, cooled and pelletized through a twin-screw extruder to obtain modified pellets.

[0104] The modified pellets were then dried at 110 °C for 4 h;

[0105] Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to maintain the material temperature at 250°C;

[0106] The molten material is poured into the mold through the die, cooled and demoulded, and then extruded into a cylinder; the cylinder is then immersed in 95°C water for 2.5 hours;

[0107] The soaked tube material is turned into guide ring products of specific size according to the drawing;

[0108] Fix the processed product on a supporting fixture and place it under 120℃ for 3 hours;

[0109] Machine the opening as needed.

[0110] Comparative Example 2

[0111] According to the weight ratio, 55 parts of PA6 material, 20 parts of cylindrical glass fiber, 20 parts of glass microspheres, 0.3 parts of antioxidant, 0.6 parts of lubricant, and 5 parts of MoS2 wear-resistant agent were weighed.

[0112] The lubricant, MoS2, antioxidant, and glass microspheres were blended at high speed in a vertical mixer for 10 minutes and then added from the main feed port of a twin-screw extruder.

[0113] Add PA6 material from the twin-screw extruder through the main feed port;

[0114] Add chopped cylindrical glass fibers through the dedicated side feed port of the twin-screw extruder;

[0115] The above materials are melted, extruded, cooled and pelletized through a twin-screw extruder to obtain modified pellets.

[0116] The modified pellets were then dried at 110 °C for 4 h;

[0117] Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to maintain the material temperature at 250°C;

[0118] The molten material is poured into the mold through the die, cooled and demoulded, and then extruded into a cylinder; the cylinder is then immersed in 95°C water for 2.5 hours;

[0119] The soaked tube material is turned into guide ring products of specific size according to the drawing;

[0120] Fix the processed product on a supporting fixture and place it under 120℃ for 3 hours;

[0121] Machine the opening as needed.

[0122] Comparative Example 3

[0123] According to the weight ratio, 55 parts of PA6 material, 40 parts of cylindrical glass fiber, 0.3 parts of antioxidant, 0.6 parts of lubricant, and 5 parts of MoS2 wear-resistant agent were weighed.

[0124] The lubricant, MoS2 and antioxidant were blended at high speed in a vertical mixer for 10 minutes and then added from the main feed port of a twin-screw extruder;

[0125] Add PA6 material from the twin-screw extruder through the main feed port;

[0126] Add chopped cylindrical glass fibers through the dedicated side feed port of the twin-screw extruder;

[0127] The above materials are melted, extruded, cooled and pelletized through a twin-screw extruder to obtain modified pellets.

[0128] The modified pellets were then dried at 110 °C for 4 h;

[0129] Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to maintain the material temperature at 250°C;

[0130] The molten material is poured into the mold through the die, cooled and demoulded, and then extruded into a cylinder; the cylinder is then immersed in 95°C water for 2.5 hours;

[0131] The soaked tube material is turned into guide ring products of specific size according to the drawing;

[0132] Fix the processed product on a supporting fixture and place it under 120℃ for 3 hours;

[0133] Machine the opening as needed.

[0134] The materials prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were injection molded into standard specimens for material performance testing. The standard specimens needed to be conditioned at 23° C. / 50-55% RH for at least 24 hours.

[0135] Test methods for each project:

[0136] Flexural modulus: Sample size refers to ISO178, rate 2mm / min;

[0137] Tensile strength: Sample size refers to ISO527, tensile rate 5mm / min.

[0138] Compression strength: Sample size refers to standard ISO604, speed 1mm / min.

[0139] Warpage test method: Place guide rings made of different materials on a rigid surface, fix one side of the guide ring opening, and measure the warpage at the diagonal position with a feeler gauge (multiple points can also be measured as needed). Then, place the product on an image measuring instrument and use automatic optical focus scanning to test the required data.

[0140] In addition, the materials prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were made into guide rings, and their dimensional changes were observed.

[0141] The test results are shown in Table 1 below.

[0142] Table 1 Comparative Examples and Example Test Results

[0143]

[0144] ★★★ means “good”; ★★ means “better”; ★ means “bad”.

[0145] As can be seen from the above examples and comparative examples, the low-warpage polyamide modified material of the present invention exhibits superior low warpage and compressive strength compared to conventional single glass fiber pellets. The guide rings for mining truck cylinders produced using this pellet are free of floating fibers, have a low gloss, and exhibit minimal deformation. Furthermore, the injection molding method effectively reduces investment in production equipment, offering simplified production and flexible conversion options. While glass microbeads effectively reduce product warpage, adding more does not guarantee better results; exceeding this level significantly reduces the overall performance of the material.

Claims

1. A guide ring for a mining truck oil cylinder, characterized in that: The invention comprises the following components in parts by weight: 55 parts of PA6 material, 10 parts of flat glass fiber, 30 parts of glass microspheres, 0.3 parts of antioxidant, 0.6 parts of lubricant, and 5 parts of MoS2 wear-resistant agent; Among them, the viscosity of PA6 material is 2.2, the melting point is 210℃~230℃, the length of flat glass fiber is 6mm, and the aspect ratio is 6:1; the particle size of glass microbeads is 15~125μm; the lubricant is calcium stearate; The specific preparation method is prepared according to the following steps: The lubricant, MoS2, antioxidant, and glass microspheres were blended at high speed in a vertical mixer for 10 minutes and added from the main feed port of a twin-screw extruder; Add PA6 material from the twin-screw extruder through the main feed port; Add the chopped flat glass fibers through a dedicated side feed port of the twin-screw extruder; The above materials are melted, extruded, cooled and pelletized by a twin-screw extruder to obtain modified pellets; The modified pellets were then dried at 110 °C for 4 h; Add the dried modified pellets into the barrel of the injection machine, heat and melt them, and transport them to a storage barrel with a heat preservation device to keep the material temperature at 250°C; The molten material is injected into the mold through the die, wherein the injection pressure of the injection machine is 20-30 MPa, the mold clamping pressure is 25-35 MPa, the mold temperature is 80℃-95℃, and the barrel is extruded after cooling and demolding; then the barrel is placed in 95℃ water and soaked for 2.5 hours; According to the drawings, the soaked barrel material is turned into guide ring products of specific sizes; Fix the processed product on a supporting fixture and place it under 120°C for 3 hours; Machine the opening as required.

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