Preparation method of floating-fiber-free high-strength nylon composite material

Abstract

The invention discloses a floating-fiber-free high-strength nylon composite material preparation method, which comprises: modifying glass fibers, carrying out melt mixing with an ethylene-vinyl alcohol polymer to obtain a modified glass fiber master batch, modifying short-cut flat glass fibers, mixing with basic magnesium sulfate whiskers, and carrying out extrusion molding to obtain the floating-fiber-free high-strength nylon composite material. Melting and granulating with an ethylene-octylene copolymer graft to obtain a modified powder master batch; finally, PA66 resin, the modified glass fiber master batch, MXD6 resin, the modified powder master batch, a cross-linking agent, a heat stabilizer and an antioxidant are subjected to melt extrusion granulation, and the floating-fiber-free high-strength nylon composite material is prepared, has the advantages of no floating fiber phenomenon, excellent mechanical strength, low water absorption rate, high dimensional stability and the like, and can be applied to manufacturing of toilet lid damper cores.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a preparation method of a high-strength nylon composite material without floating fibers. BACKGROUND

[0002] As the core component of controlling the stable opening and closing of the toilet cover, the toilet cover damper core controls the opening and closing of the toilet cover smoothly through the hydraulic or pneumatic buffer principle, avoids impact noise and safety hazards, has the characteristics of neat appearance, excellent structural strength, moisture resistance, heat resistance, and precise transmission, which is also the core requirement of the material selection of the component in the bathroom industry. High-quality toilet cover damper cores not only provide stable support and smooth opening and closing experience for toilet covers, but also need to adapt to the long-term humid environment and the use scenario of being easily contacted with cleaning agents in the bathroom, and have good chemical stability. In addition, the characteristics of no flaws and no foreign matter protrusions on the surface can avoid assembly jamming or friction noise, and the strong mechanical properties can meet the long-term repeated opening and closing use requirements, and guarantee the core advantages of product silence and durability.

[0003] Nylon 66 (PA66) is often used as a base material to be compounded with reinforcing fibers to make toilet cover damper cores due to its excellent mechanical strength, fatigue resistance, and processing fluidity. However, there are the following problems in the actual preparation and application process: first, in the processing process, the reinforcing fibers are easy to gather along the melt flow direction or protrude on the surface of the product, forming floating fiber defects, which affect the consistency of the product appearance and the sealing performance of the assembly; second, the intrinsic strength of PA66 is low, which easily leads to material delamination and fracture under long-term repeated bending and torsional stress, reducing the service life of the damper core, and generally requires the tensile strength of the material to be ≥220 MPa and the bending strength to be ≥310 MPa; third, PA66 has a high water absorption rate, which easily causes dimensional expansion in a humid environment, leading to a decrease in the transmission gap of the damper core, an increase in the opening and closing resistance, and even a jamming phenomenon, and generally, a water absorption rate ≤0.4% is beneficial to the stable operation of the product; fourth, the shrinkage rate of the material forming is uneven, which easily causes warping deformation due to the release of internal stress, leading to a decrease in the assembly precision of the damper core and the toilet cover, affecting the damping adjustment effect, and generally, a shrinkage rate ≤0.4% is beneficial to the size matching of the product.

[0004] Therefore, it is of important market value and practical significance to develop a nylon 66 composite material with the characteristics of no floating fibers and high strength to improve the appearance quality, structural stability, and service life of the toilet cover damper core. SUMMARY

[0005] The present application aims to provide a preparation method of a high-strength nylon composite material without floating fibers, and the prepared nylon composite material has the characteristics of no floating fiber phenomenon, good mechanical strength, low water absorption rate, and high dimensional stability.

[0006] In order to achieve the above purpose, the solution of the present application is: A preparation method of a no-float high-strength nylon composite material, comprising the following steps: Step 1, first soak the glass fiber in anhydrous ethanol for 0.5-1 hours, then wash with deionized water, dry and put into 1-2 g / L dopamine hydrochloride solution, stir at room temperature for 4-6 hours and wash with deionized water, dry to obtain modified glass fiber; Step 2, then melt mix the modified glass fiber and ethylene-vinyl alcohol polymer in a mass ratio of 8:2, the processing temperature is 200-220℃, to obtain a modified glass fiber master batch; Step 3, then soak the chopped flat glass fiber in anhydrous ethanol for 0.5-1 hours, then wash with deionized water, dry and put into 1-2 g / L dopamine hydrochloride solution, stir at room temperature for 4-6 hours and wash with deionized water, dry to obtain modified flat glass fiber; Step 4, then mix the modified flat glass fiber and basic magnesium sulfate whisker in a mass ratio of 1:0.5-1 to obtain a mixture, then melt mix the mixture and ethylene-octene copolymer grafting product in a mass ratio of 8:2, the processing temperature is 200-220℃, to obtain a modified powder master batch; Step 5, then according to the formula proportion, melt extrude and granulate 25 wt % ~ 40 wt % PA66 resin, 25 wt % ~ 35 wt % modified glass fiber master batch, 15 wt % ~ 25 wt % MXD6 resin, 10 wt % ~22 wt % modified powder master batch, 1 wt % ~ 3 wt % crosslinking agent, 0.5 wt % ~1 wt % heat stabilizer and 0.2 wt % ~ 0.5 wt % antioxidant through a twin-screw extruder, the extrusion temperature is 220-260℃, to obtain the no-float high-strength nylon composite material.

[0007] In step 1, the mass ratio of the glass fiber to the dopamine hydrochloride solution is 1:2-3.

[0008] In step 1, the drying temperature is 60℃.

[0009] In step 3, the cross-sectional width of the chopped flat glass fiber is 5-10 μm.

[0010] In step 3, the mass ratio of the short-cut flat glass fiber to the dopamine hydrochloride solution is 1:3-4.

[0011] In step 3, the drying temperature is 60 DEG C.

[0012] In step 4, the ethylene octene copolymer grafting agent is ethylene octene copolymer grafting maleic anhydride and / or ethylene octene copolymer grafting glycidyl methacrylate.

[0013] In step 5, the crosslinking agent is polypropylene glycol diglycidyl ether and / or polyethylene glycol diglycidyl ether.

[0014] In step 5, the heat stabilizer is at least one of zinc stearate, calcium stearate and magnesium stearate.

[0015] In step 5, the antioxidant is at least one of antioxidant 1010, antioxidant 1076 and antioxidant 168.

[0016] After the above technical solution, the preparation method of the high-strength nylon composite material without floating fibers has the following beneficial effects: First, the glass fiber and the flat glass fiber are respectively surface modified to enhance the interface action between the reinforcing fiber and the resin, and ethylene-vinyl alcohol is selected to be blended with the glass fiber, and ethylene octene copolymer grafting agent is selected to be blended with the flat glass fiber, so as to realize effective coating of the glass fiber through physical or chemical anchoring effect, prevent the glass fiber from being oriented and aggregated in the flow direction or exposed on the product surface due to the screw shearing, and realize the modified product surface smooth and no floating fiber phenomenon. Secondly, the PA66 is modified by using MXD6 resin, modified glass fiber master batch, modified powder master batch and crosslinking agent, which not only improves the dispersion effect of the glass fiber in the matrix resin, but also enhances the interface action and synergistic effect between the multiple phases, and realizes the multiple improvement of the strength, modulus and toughness of the composite material. Thirdly, the PA66 is modified by using MXD6 resin, modified glass fiber master batch, modified powder master batch and crosslinking agent, on the one hand, the water absorption of the composite system is reduced by introducing hydrophobic resin and filler; on the other hand, the crosslinking reaction is formed between the crosslinking agent and the PA66 resin, the dispersed phase and other materials (MXD6 resin, glass fiber, basic magnesium sulfate whisker, etc.), the original amide structure is changed, and then the significant moisture absorption of PA66 is inhibited, so that the water absorption of the composite material is greatly reduced. Finally, MXD6 resin, modified glass fiber masterbatch and modified powder masterbatch are used to modify PA66, the dimensional stability of the product is improved by increasing the intrinsic thermal stability of PA66; at the same time, the crosslinking agent is introduced to modify the composite system, the stability of the three-dimensional structure of the composite system is improved by enhancing the physical entanglement or chemical bonding between the phases, and the low shrinkage of PA66 composite material is realized under the synergistic effect of the two, which ensures the high stability of the product size. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The photo of the toilet cover damper core product processed from the high-strength nylon composite material without floating fibers prepared in Example 1. DETAILED DESCRIPTION

[0018] In order to further explain the technical scheme of the present application, the present application will be described in detail below through specific examples.

[0019] Example 1 A preparation method of a high-strength nylon composite material without floating fibers, comprising the following steps: Step 1, first immerse the glass fiber in anhydrous ethanol for 1 hour, then wash with deionized water, dry at 60℃, and then put into a 2 g / L dopamine hydrochloride solution, wherein the mass ratio of glass fiber to dopamine hydrochloride solution is 1:2, then stir at room temperature for 4 hours and wash with deionized water, dry at 60℃, to obtain modified glass fiber; Step 2, then melt mix the modified glass fiber and ethylene-vinyl alcohol polymer at a mass ratio of 8:2, and the processing temperature is changed from 200℃, 220℃, 215℃ one by one, to obtain a modified glass fiber masterbatch; Step 3, then immerse the short-cut flat glass fiber with a cross-sectional width of 8 μm in anhydrous ethanol for 0.5 hours, then wash with deionized water, dry at 60℃, and then put into a 1 g / L dopamine hydrochloride solution, wherein the mass ratio of short-cut flat glass fiber to dopamine hydrochloride solution is 1:3, then stir at room temperature for 6 hours and wash with deionized water, dry at 60℃, to obtain modified flat glass fiber; Step 4, then mix the modified flat glass fiber and basic magnesium sulfate whisker at a mass ratio of 1:1 to obtain a mixture, and then melt mix the mixture and ethylene-octene copolymer grafted glycidyl methacrylate at a mass ratio of 8:2, and the processing temperature is changed from 200℃, 218℃, 220℃ one by one, to obtain a modified powder masterbatch; Step 5, then according to the formula proportion, 30 wt % PA66 resin, 30 wt % modified glass fiber masterbatch, 15 wtMXD6 resin, 22 wt Modified powder masterbatch, 2 wt Polyethylene glycol diglycidyl ether, 0.5 wt Calcium stearate and 0.5 wt Antioxidant 1076 was melt-extruded by a twin-screw extruder, and the extrusion temperature was changed from 220℃, 240℃, 258℃, 260℃, 257℃, 255℃ one by one to obtain the high-strength nylon composite material without floating fibers.

[0020] Example 2 A preparation method of a high-strength nylon composite material without floating fibers, comprising the following steps: Step 1, first soak the glass fiber in anhydrous ethanol for 0.5 hours, then wash with deionized water, dry at 60℃, and then put into 1.5 g / L dopamine hydrochloride solution, wherein the mass ratio of glass fiber to dopamine hydrochloride solution is 1:3, stir at room temperature for 6 hours and wash with deionized water, dry at 60℃, to obtain modified glass fiber; Step 2, then melt mix the modified glass fiber with ethylene-vinyl alcohol polymer at a mass ratio of 8:2, and the processing temperature is changed from 200℃, 220℃, 218℃ one by one to obtain a modified glass fiber masterbatch; Step 3, then soak the short-cut flat glass fiber with a cross-sectional width of 5 μm in anhydrous ethanol for 1 hour, then wash with deionized water, dry at 60℃, and then put into 2 g / L dopamine hydrochloride solution, wherein the mass ratio of short-cut flat glass fiber to dopamine hydrochloride solution is 1:4, stir at room temperature for 5 hours and wash with deionized water, dry at 60℃, to obtain modified flat glass fiber; Step 4, then mix the modified flat glass fiber with basic magnesium sulfate whisker at a mass ratio of 1:0.5 to obtain a mixture, and then melt mix the mixture with ethylene-octene copolymer grafted maleic anhydride at a mass ratio of 8:2, and the processing temperature is changed from 200℃, 220℃, 216℃ one by one to obtain a modified powder masterbatch; Step 5, then according to the formula proportion, 28 wt PA66 resin, 35 wt Modified glass fiber masterbatch, 20 wt MXD6 resin, 14.5 wt Modified powder masterbatch, 1 . 3 wt Polypropylene glycol diglycidyl ether, 1.0 wt Zinc stearate and 0.2 wtAntioxidant 1010 was melt-extruded and granulated using a twin-screw extruder. The extrusion temperature was varied from 220℃, 242℃, 259℃, 260℃, 258℃, to 257℃ to obtain the fiber-free high-strength nylon composite material.

[0021] Example 3 A method for preparing a fiber-free, high-strength nylon composite material includes the following steps: Step 1: First, soak the glass fiber in anhydrous ethanol for 1 hour, then wash it with deionized water, dry it at 60°C, and then put it into a 1 g / L dopamine hydrochloride solution, wherein the mass ratio of glass fiber to dopamine hydrochloride solution is 1:2. Stir it at room temperature for 5 hours, wash it with deionized water, and dry it at 60°C to obtain modified glass fiber. Step 2: Then, the modified glass fiber and ethylene-vinyl alcohol polymer are melt-mixed at a mass ratio of 8:2, and the processing temperature is changed from 200℃, 215℃ and 220℃ one by one to obtain the modified glass fiber masterbatch. Step 3: Then, chopped flat glass fibers with a cross-sectional width of 10 μm are soaked in anhydrous ethanol for 1 hour, washed with deionized water, dried at 60°C, and then placed in a 2 g / L dopamine hydrochloride solution, wherein the mass ratio of chopped flat glass fibers to dopamine hydrochloride solution is 1:4. The mixture is stirred at room temperature for 4 hours, washed with deionized water, and dried at 60°C to obtain modified flat glass fibers. Step 4: Then, the modified flat glass fiber and basic magnesium sulfate whiskers are mixed at a mass ratio of 1:1 to obtain a mixture. The mixture is then melt-mixed with ethylene octene copolymer grafted glycidyl methacrylate at a mass ratio of 8:2. The processing temperature is changed from 200℃, 220℃ and 217℃ one by one to obtain the modified powder masterbatch. Step 5: Then, according to the recipe proportions, add 25.5... wt % PA66 resin, 35 wt % Modified glass fiber masterbatch, 20 wt % MXD6 resin, 15 wt % Modified powder masterbatch, 3 wt % polyethylene glycol diglycidyl ether, 1 wt % magnesium stearate and 0.5 wt Antioxidant 168 was melt-extruded and granulated using a twin-screw extruder. The extrusion temperature was changed from 220℃, 247℃, 260℃, 260℃, 257℃, and 254℃ to obtain the fiber-free high-strength nylon composite material.

[0022] Comparative Example 1 PA66 was directly melt-extruded and granulated using a twin-screw extruder, with the extrusion temperature varying from 220℃, 240℃, 258℃, 260℃, 257℃, to 255℃ to obtain PA66 material.

[0023] Comparative Example 2 The difference from Example 1 is that steps 1 to 4 are omitted, and unmodified glass fibers and chopped flat glass fibers are directly added according to the formula ratio, with 30 wt % PA66 resin, 30 wt % glass fiber, 15 wt % MXD6 resin, 22 wt % Composite powder (short-cut flat glass fibers and basic magnesium sulfate whiskers mixed in a 1:1 mass ratio), 2 wt % polyethylene glycol diglycidyl ether, 0.5 wt % calcium stearate and 0.5 wt Antioxidant 1076 was melt-extruded and granulated using a twin-screw extruder. The extrusion temperature was changed from 220℃, 240℃, 258℃, 260℃, 257℃ and 255℃ to obtain modified nylon composite materials.

[0024] Comparative Example 3 The difference from Example 1 is that MXD6 resin is not added in step 5, and 45% of the resin is added according to the formula ratio. wt % PA66 resin, 30 wt % glass fiber, 22 wt % Modified powder masterbatch, 2 wt % polyethylene glycol diglycidyl ether, 0.5 wt % calcium stearate and 0.5 wt Antioxidant 1076 was melt-extruded and granulated using a twin-screw extruder. The extrusion temperature was changed from 220℃, 240℃, 258℃, 260℃, 257℃ and 255℃ to obtain modified nylon composite materials.

[0025] Comparative Example 4 The difference from Example 1 is that steps 3-4 are omitted, and the modified powder masterbatch is not added in step 5. Instead, 30... wt % PA66 resin, 30 wt % Modified glass fiber masterbatch, 15 wt % MXD6 resin, 22 wt % Powder Masterbatch Basic Magnesium Sulfate Whiskers, 2 wt % polyethylene glycol diglycidyl ether, 0.5 wt % calcium stearate and 0.5 wtAntioxidant 1076 was melt-extruded and granulated using a twin-screw extruder. The extrusion temperature was changed from 220℃, 240℃, 258℃, 260℃, 257℃ and 255℃ to obtain modified nylon composite materials.

[0026] Comparative Example 5 The difference from Example 1 is that, in step 4, basic magnesium sulfate whiskers are not added. Instead, the modified flat glass fiber is directly melt-mixed with ethylene octene copolymer grafted glycidyl methacrylate to obtain a modified powder masterbatch. Then, in step 5, according to the formula ratio, 30 wt % PA66 resin, 30 wt % Modified glass fiber masterbatch, 15 wt % MXD6 resin, 22 wt % Modified powder masterbatch, 2 wt % polyethylene glycol diglycidyl ether, 0.5 wt % calcium stearate and 0.5 wt Antioxidant 1076 was melt-extruded and granulated using a twin-screw extruder. The extrusion temperature was changed from 220℃, 240℃, 258℃, 260℃, 257℃ and 255℃ to obtain modified nylon composite materials.

[0027] Comparative Example 6 The difference from Example 1 is that no crosslinking agent is added in step 5, and 32 is added according to the formulation ratio. wt % PA66 resin, 30 wt % Modified glass fiber masterbatch, 15 wt % MXD6 resin, 22 wt % Modified powder masterbatch, 0.5 wt % calcium stearate and 0.5 wt Antioxidant 1076 was melt-extruded and granulated using a twin-screw extruder. The extrusion temperature was changed from 220℃, 240℃, 258℃, 260℃, 257℃ and 255℃ to obtain modified nylon composite materials.

[0028] In this invention, the glass fiber, ethylene-vinyl alcohol polymer, dopamine hydrochloride solution, chopped flat glass fiber, basic magnesium sulfate whiskers, ethylene octene copolymer graft, PA66 resin, MXD6 resin, crosslinking agent, heat stabilizer and antioxidant used are all materials and reagents known in the art.

[0029] Performance testing: The nylon composite materials prepared in each embodiment and comparative example were made into test strips according to the relevant performance standards below. The tensile strength (ISO 527-1 / 2), flexural strength (ISO 178 / 2010), notched impact strength (ISO 180 / 2019), water absorption (GB / T 1034-2008), and shrinkage (GB / T 17037.4-2003) of the nylon composite materials were measured. At the same time, the surface fiber floating condition of each nylon composite material after being made into toilet seat damper cores (products) was observed. The results are shown in Table 1.

[0030] Table 1. Performance results of nylon composite materials prepared in each example and comparative example.

[0031] As can be seen from the data in Table 1, the fiber-free high-strength nylon composite materials prepared in Examples 1-3 exhibit excellent performance, with tensile strength not less than 224 MPa, generally maintained between 224 and 235 MPa; flexural strength not less than 313 MPa, generally maintained between 313 and 328 MPa; and notched impact strength not less than 16.7 kJ / m. 2 It remained basically between 16.7 and 18.2 kJ / m³. 2 The water absorption rate is no higher than 0.4%, generally maintained between 0.3% and 0.4%; the shrinkage rate is no higher than 0.3%, generally maintained between 0.2% and 0.3%; from Figure 1 It can be seen that the products obtained from subsequent processing did not exhibit fiber floating.

[0032] Comparative Example 1 shows that pure nylon 66 material suffers from low strength, high water absorption, high shrinkage, and insufficient toughness, making it unsuitable for use as a toilet seat damper core. Modification of nylon 66 material effectively overcomes these shortcomings.

[0033] Compared with Example 1, in Comparative Example 2, without modification, the toughness of the glass fiber and chopped flat glass fiber decreased significantly, the shrinkage rate increased, and fiber floating occurred. In Comparative Example 3, without the addition of MXD6 resin, the toughness of the material decreased, and the water absorption and shrinkage rate increased. In Comparative Example 4, without the addition of chopped flat fibers but replacing them with basic magnesium sulfate whiskers, the strength of the material decreased, and the water absorption and shrinkage rate increased. In Comparative Example 5, without the addition of basic magnesium sulfate whiskers, the toughness of the material decreased, and the shrinkage rate increased. In Comparative Example 6, without the addition of a crosslinking agent, the strength of the material decreased, and the water absorption and shrinkage rate increased significantly, failing to meet the application requirements.

[0034] Given that the specially formulated high-strength nylon composite material without floating fibers of this invention possesses the aforementioned excellent properties, it is particularly suitable for the manufacture of toilet seat damper cores.

[0035] The above embodiments and figures are not intended to limit the product form and style of the present invention. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of the present invention.

Claims

1. A process for the production of a high-strength nylon composite without floating fibers, characterized by: The method comprises the following steps: Step 1, the glass fiber is soaked in anhydrous ethanol for 0.5-1 hours, then washed with deionized water, dried, and then placed in a 1-2 g / L dopamine hydrochloride solution, stirred at room temperature for 4-6 hours, washed with deionized water, and dried to obtain modified glass fiber; Step 2, then the modified glass fiber is melt-mixed with ethylene-vinyl alcohol polymer at a mass ratio of 8:2, and the processing temperature is 200-220℃ to obtain a modified glass fiber master batch; Step 3, then the chopped flat glass fiber is soaked in anhydrous ethanol for 0.5-1 hours, then washed with deionized water, dried, and then placed in a 1-2 g / L dopamine hydrochloride solution, stirred at room temperature for 4-6 hours, washed with deionized water, and dried to obtain modified flat glass fiber; Step 4, then the modified flat glass fiber is mixed with basic magnesium sulfate whisker at a mass ratio of 1:0.5-1 to obtain a mixture, and then the mixture is melt-mixed with ethylene-octene copolymer grafting product at a mass ratio of 8:2, and the processing temperature is 200-220℃ to obtain a modified powder master batch; Step 5, then according to the formula proportion, 25 wt % ~ 40 wt % PA66 resin, 25 wt % ~ 35 wt % modified glass fiber masterbatch, 15 wt % ~ 25 wt % MXD6 resin, 10 wt % ~22 wt % modified powder masterbatch, 1 wt % ~ 3 wt % crosslinking agent, 0.5 wt % ~1 wt % heat stabilizer and 0.2 wt % ~ 0.5 wt % antioxidant melt extrusion granulation by twin screw extruder, the extrusion temperature is 220~260℃, obtain the no floating fiber high strength nylon composite material.

2. The method of claim 1, wherein the method is characterized by: In step 1, the mass ratio of the glass fiber to the dopamine hydrochloride solution is 1:2-3.

3. The method of claim 1, wherein the method further comprises the step of: 3.

1. applying a layer of adhesive on the surface of the first layer of the composite material. In step 1, the drying temperature is 60℃.

4. The method of claim 1, wherein the method further comprises the step of: 5 applying a coating of a material to the surface of the nylon fabric. 6 In step 3, the cross-sectional width of the chopped flat glass fiber is 5-10 μm.

5. The method for preparing a fiber-free high-strength nylon composite material according to claim 1, characterized in that: In step 3, the mass ratio of the chopped flat glass fiber to the dopamine hydrochloride solution is 1:3-4.

6. The method of claim 1, wherein the high-strength nylon composite material is prepared without floating fibers. In step 3, the drying temperature is 60℃.

7. The method for preparing a fiber-free high-strength nylon composite material according to claim 1, characterized in that: In step 4, the ethylene-octene copolymer grafting product is ethylene-octene copolymer grafted maleic anhydride and / or ethylene-octene copolymer grafted glycidyl methacrylate.

8. The method of claim 1, wherein the high-strength nylon composite material is prepared without floating fibers. In step 5, the crosslinking agent is polypropylene glycol diglycidyl ether and / or polyethylene glycol diglycidyl ether.

9. The method for preparing a fiber-free high-strength nylon composite material according to claim 1, characterized in that: In step 5, the heat stabilizer is at least one of zinc stearate, calcium stearate, and magnesium stearate.

10. The method of claim 1, wherein the high-strength nylon composite material is prepared without floating fibers. In step 5, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

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