A recyclable bio-based flame-retardant composite sleeper and a preparation method thereof

Abstract

The invention discloses a recyclable bio-based flame-retardant composite sleeper and a preparation method thereof. The raw materials of the composite sleeper are component A and component B in a mass ratio of 1:1; the component A includes: bio-based polyol; self-catalytic epoxy-modified polyol; ultraviolet absorber; antioxidant; foam stabilizer; diselenide diol; deionized water; the component B includes: isocyanate; adhesion promoter A; adhesion promoter B; the preparation method is: heating the component A and the component B respectively, then mixing the component A and the component B evenly and injecting them into a mold with long glass fiber, molding, and cutting to obtain the recyclable bio-based flame-retardant composite sleeper. The recyclable bio-based flame-retardant composite sleeper prepared by the invention has the characteristics of high flame retardancy, low density, high bending strength, high bending elastic modulus, and excellent impact resistance, and can be recycled and reused through chemical degradation, effectively avoiding environmental pollution.

Description

Technical Field

[0001] The invention relates to the technical field of sleepers for railway track construction, in particular to a recyclable bio-based flame-retardant composite sleeper and a preparation method thereof. Background Art

[0002] A large number of sleepers are used in railway construction. Sleepers play an important role in supporting rails and maintaining track gauge. They also provide sufficient rigidity and lateral and longitudinal resistance, and transfer the load from vehicles from the rails to the roadbed.

[0003] Common sleepers include concrete sleepers, wooden sleepers and composite sleepers. Wooden sleepers are easy to manufacture, have a wide range of materials, have a certain degree of elasticity, are light in weight, are less affected by temperature changes in the surrounding medium, and are easy to replace. They were widely used in the early stages of construction, especially in railway beam bridges, which almost all use wooden sleepers. However, wooden sleepers have also exposed many shortcomings in long-term use, including poor pressure bearing capacity, easy corrosion and cracking, poor fastener retention ability with its accessories, easy loosening of spikes, easy loosening and misalignment of hook bolts, etc. At the same time, they have a short service life, large quality dispersion, and are greatly affected by humidity. The service life of some wooden sleepers made of poor materials is even only 1-2 years.

[0004] Concrete sleepers are a widely used track structure in railway projects around the world. They are stable, strong and rigid. However, their prefabrication technology is relatively complex, and they place high demands on the elasticity of the components under the rail. They are also difficult to transport and install due to their heavy weight. At the same time, as high-speed rail speeds up, higher requirements are placed on the vibration reduction of sleepers. Therefore, concrete sleepers have been gradually eliminated.

[0005] Composite sleepers are made of glass fiber reinforced polyurethane foam material. They are lightweight, have excellent shock absorption, are corrosion-resistant, and have high strength, making them widely used in steel bridges and wet road sections.

[0006] At present, polyurethane composite sleepers are all prepared using polyether polyurethane, which has poor weather resistance. In addition, since a large amount of catalysts are added during the preparation process, uneven stirring occurs. In addition, polyether polyols contain alkalinity, and their characteristics of rapid heat release and slow heat dissipation will cause many side reactions (such as the reaction of carbamate, urea and isocyanate), resulting in heartburn problems on the composite sleepers. In addition, the existing polyurethane composite sleepers are difficult to recycle and reuse, and are likely to cause environmental pollution after disposal. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a recyclable bio-based flame-retardant composite sleeper and a preparation method thereof, so as to improve the comprehensive mechanical properties and weather resistance of the composite sleeper, and also be able to be recycled and reused to avoid the occurrence of environmental pollution caused by discarding.

[0008] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0009] A recyclable bio-based flame-retardant composite sleeper, wherein the raw materials of the composite sleeper are component A and component B in a mass ratio of 1:1;

[0010] The A component includes the following components in parts by weight:

[0011] Bio-based polyols: 70-80 parts;

[0012] Self-catalytic epoxy modified polyol: 10-15 parts;

[0013] Ultraviolet absorber: 1-2 parts;

[0014] Antioxidant: 1-2 parts;

[0015] Foam stabilizer: 1-3 parts;

[0016] Diselendiol: 1-3 parts;

[0017] Deionized water: 0.2-0.4 parts;

[0018] The B component includes the following components in parts by weight:

[0019] Isocyanate: 87-90 parts;

[0020] Adhesion promoter A: 5-7.5 parts;

[0021] Adhesion promoter B: 4-7 parts.

[0022] The above-mentioned recyclable bio-based flame-retardant composite sleeper, the bio-based polyol is prepared from the following raw materials in parts by weight:

[0023] Castor oil: 63-68 parts;

[0024] 4,4,-dicyclohexylmethanediamine: 1-2 parts;

[0025] Bio-based glycerol: 19-23 parts;

[0026] Adipic acid: 13-17 parts;

[0027] When preparing bio-based polyols, castor oil, 4,4,-dicyclohexylmethanediamine and bio-based glycerol in the above-mentioned weight proportions are added into a four-necked bottle equipped with a thermometer and a distillation device and capable of being evacuated, stirred at 180°C for 2 hours, then heated to 210°C and maintained for 2.5-3 hours, and then cooled to 120°C and adipic acid is added; the temperature is set to 190°C, evacuated, the vacuum degree is set to 0.9, and then the temperature is gradually raised to 230°C and maintained for 2 hours. When the acid value is tested to be less than 10 mgKOH / g, heating is stopped to obtain bio-based polyols.

[0028] The above-mentioned recyclable bio-based flame-retardant composite sleeper, the self-catalytic epoxy-modified polyol is prepared from the following raw materials in parts by weight:

[0029] Epoxy resin E-44: 45-55 parts;

[0030] Epoxy resin E-51: 15-20 parts;

[0031] Diethanolamine: 15-30 parts;

[0032] Methylethanolamine: 10-15 parts;

[0033] When preparing self-catalytic epoxy-modified polyols, add the above-mentioned weight proportions of epoxy resin E-44 and epoxy resin E-51 into a reaction kettle, add diethanolamine dropwise, after 10-15 minutes of dropwise addition, set the temperature to 45-50°C, continue stirring for 30 minutes, then add methylethanolamine, set the temperature to 85-95°C, heat for 2 hours, and obtain self-catalytic epoxy-modified polyols.

[0034] In the above-mentioned recyclable bio-based flame-retardant composite sleeper, the ultraviolet absorber is at least one of BASF Uvinul3050, BASF UV327 or Jinan Xiangfeng Weiye Chemical Co., Ltd. UV531; the antioxidant is BASF Irganox1010; the foam stabilizer is at least one of Meside M-8805, Shanghai Baiang Chemical BA-9738 or Jining Huakai Resin HK-314.

[0035] In the above-mentioned recyclable bio-based flame-retardant composite sleeper, the diselenide diol is a mixture of one or more of bis(1-hydroxyethyl) diselenide, bis(1-hydroxypropyl) diselenide and bis(1-hydroxybutyl) diselenide.

[0036] The above-mentioned recyclable bio-based flame-retardant composite sleeper, the preparation method of component A is: add bio-based polyol, self-catalytic epoxy modified polyol, ultraviolet absorber, antioxidant, and diselenide diol into a high-speed dispersion kettle according to weight proportions, set the stirring speed to 200-300r / min, and stir for 15-20min; then add foam stabilizer and deionized water, set the stirring speed to 1500-1800r / min, and high-speed disperse for 30min to obtain component A.

[0037] In the above-mentioned recyclable bio-based flame-retardant composite sleeper, the bonding promoter A in the B component is prepared from the following raw materials in parts by weight:

[0038] TDI: 35 parts;

[0039] KH-560: 45 parts;

[0040] Methylbenzylamine: 30 parts;

[0041] When preparing adhesion promoter A, add the above-mentioned weight proportions of KH-560 and methylbenzylamine into a reaction kettle, set the temperature to 95°C-105°C, react for 2-2.5 hours, then add TDI and set the temperature to 55-65°C, heat the reaction for 3-3.5 hours, and stop heating to obtain adhesion promoter A.

[0042] In the above-mentioned recyclable bio-based flame-retardant composite sleeper, the bonding promoter B in the B component is prepared from the following raw materials in parts by weight:

[0043] TDI: 34 parts;

[0044] 3-(Acryloyloxy)propyltrimethoxysilane: 46 parts;

[0045] Benzylamine: 20 parts;

[0046] When preparing adhesion promoter B, add the above-mentioned weight proportions of 3-(acryloyloxy)propyltrimethoxysilane and benzylamine into the reaction kettle, set the temperature to 95°C-105°C, and react for 2-2.5 hours; then add TDI, set the temperature to 25-35°C, heat the reaction for 3-3.5 hours, and stop heating to obtain adhesion promoter B.

[0047] The preparation method of the B component of the above-mentioned recyclable bio-based flame-retardant composite sleeper is as follows: adding isocyanate, adhesion promoter A and adhesion promoter B in a closed reaction kettle according to weight parts; setting the stirring speed to 45-55r / min, stirring for 35-45min, and obtaining the B component.

[0048] A preparation method of a recyclable bio-based flame-retardant composite sleeper specifically comprises the following steps: heating component A and component B to 24-26°C in independent material pipes respectively, then mixing component A and component B evenly and injecting them into a mold with long glass fiber, maintaining the mold temperature at 45-50°C for 35-45 minutes; compression molding, and cutting to obtain a recyclable bio-based flame-retardant composite sleeper.

[0049] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0050] The adhesion promoter A and the adhesion promoter B of the present invention carry silane and isocyanate groups, can better wet the glass fiber, can hydrolyze to produce a plurality of silanol groups in the later stage of the reaction, can undergo a condensation reaction with the silanol groups on the surface of the glass fiber, and the isocyanate groups react with the polyol components, so that after curing, the resin and the glass fiber are more firmly bonded, and the overall mechanical properties can be improved; the present invention utilizes the ester bond contained in the bio-based polyol, which interacts with the carbamate generated by the reaction of isocyanate and hydroxyl groups in the reaction process of the AB component, so that the mechanical properties of the product are excellent; and diselenide diol is used as a small molecule polyurethane chain extender, which not only improves the mechanical properties of the composite sleeper, but also improves its flame retardant properties.

[0051] The present invention utilizes the tertiary amine contained in the self-catalytic epoxy polyol as a catalyst for the reaction of isocyanate with the polyol and water. The self-catalytic effect can delay the catalysis, and the resin and the glass fiber can maintain a low viscosity during the wetting process without adding an additional catalyst. At the same time, the resin and the glass fiber can be mixed evenly, thereby shortening the curing time and improving the production efficiency.

[0052] The present invention also utilizes the property that the self-catalytic epoxy modified polyol can be evenly dispersed in the system, and the residual carboxyl groups due to incomplete reaction during the reaction process can reduce side reactions and have a certain inhibitory effect, thereby effectively eliminating the hidden danger of heartburn inside the sleeper.

[0053] The present invention increases the operating time of the sleeper by synergizing the components, wherein the fiber content is 65-67%; the prepared composite sleeper has a bending modulus greater than 15GPa, a bending strength greater than 230MPa, a shear strength greater than 21MPa, and a compressibility greater than 130MPa. In addition, the bio-based polyol in the present invention is a renewable resource, and the preparation of the composite sleeper is not only environmentally friendly, but also recyclable. DETAILED DESCRIPTION

[0054] The present invention will be further described in detail below in conjunction with specific implementation modes.

[0055] A recyclable bio-based flame-retardant composite sleeper, wherein the raw materials of the composite sleeper are component A and component B in a mass ratio of 1:1; the preparation method thereof is as follows: heating component A and component B to 24-26°C in independent material pipes respectively, then mixing component A and component B evenly and injecting them into a mold with long glass fiber, maintaining the mold temperature at 45-50°C for 35-45 minutes; and compression molding and cutting to obtain the recyclable bio-based flame-retardant composite sleeper.

[0056] In the present invention, component A includes the following components in parts by weight: bio-based polyol: 70-80 parts; self-catalytic epoxy modified polyol: 10-15 parts; ultraviolet absorber: 1-2 parts; antioxidant: 1-2 parts; foam stabilizer: 1-3 parts; diselenide diol: 1-3 parts; deionized water: 0.2-0.4 parts.

[0057] in:

[0058] The bio-based polyol is prepared from the following raw materials in parts by weight: castor oil: 63-68 parts; 4,4,-dicyclohexylmethanediamine: 1-2 parts; bio-based glycerol: 19-23 parts; adipic acid: 13-17 parts. When preparing the bio-based polyol, the castor oil, 4,4,-dicyclohexylmethanediamine and bio-based glycerol in the above parts by weight are added into a four-necked bottle equipped with a thermometer and a distillation device and can be vacuumed, stirred at 180°C for 2 hours, then heated to 210°C and maintained for 2.5-3 hours, and then cooled to 120°C and adipic acid is added; the temperature is set to 190°C, vacuumed, the vacuum degree is set to 0.9, and then gradually heated to 230°C and maintained for 2 hours. When the acid value is tested to be less than 10 mgKOH / g, heating is stopped to obtain the bio-based polyol.

[0059] The self-catalytic epoxy modified polyol is prepared from the following raw materials in parts by weight: epoxy resin E-44: 45-55 parts; epoxy resin E-51: 15-20 parts; diethanolamine: 15-30 parts; methylethanolamine: 10-15 parts. When preparing the self-catalytic epoxy modified polyol, add the above parts by weight of epoxy resin E-44 and epoxy resin E-51 into the reaction kettle, add diethanolamine dropwise, after 10-15 minutes of dropwise addition, set the temperature to 45-50°C, continue stirring for 30 minutes, then add methylethanolamine, set the temperature to 85-95°C, heat for 2 hours, and obtain the self-catalytic epoxy modified polyol.

[0060] The ultraviolet absorber is at least one of BASF Uvinul3050, BASF UV327 or Jinan Xiangfeng Weiye Chemical Co., Ltd. UV531. The antioxidant is BASF Irganox 1010. The foam stabilizer is at least one of Meside M-8805, Shanghai Baiang Chemical BA-9738 or Jining Huakai Resin HK-314. The diselenide diol is a mixture of one or more of bis(1-hydroxyethyl) diselenide, bis(1-hydroxypropyl) diselenide and bis(1-hydroxybutyl) diselenide.

[0061] The preparation method of component A is as follows: add bio-based polyol, self-catalytic epoxy-modified polyol, ultraviolet absorber, antioxidant, and diselenide diol into a high-speed dispersion kettle according to weight proportions, set the stirring speed to 200-300 r / min, and stir for 15-20 minutes; then add foam stabilizer and deionized water, set the stirring speed to 1500-1800 r / min, and high-speed disperse for 30 minutes to obtain component A.

[0062] In the present invention, component B includes the following components in parts by weight: isocyanate: 87-90 parts; adhesion promoter A: 5-7.5 parts; adhesion promoter B: 4-7 parts.

[0063] in:

[0064] The isocyanate is a mixture of PM200 in polymerized MDI and MDI-50 in isocyanate monomer, and the mass ratio of PM200 to MDI-50 is 2:1-1:1.

[0065] Adhesion promoter A is prepared from the following raw materials in parts by weight: TDI: 35 parts; KH-560: 45 parts; methylbenzylamine: 30 parts. When preparing adhesion promoter A, the above parts by weight of KH-560 and methylbenzylamine are added into a reaction kettle, the temperature is set at 95°C-105°C, the reaction is carried out for 2-2.5 hours, TDI is added and the temperature is set at 55-65°C, the reaction is heated for 3-3.5 hours, and the heating is stopped to obtain adhesion promoter A.

[0066] Adhesion promoter B is prepared from the following raw materials in parts by weight: TDI: 34 parts; 3-(acryloyloxy)propyltrimethoxysilane: 46 parts; benzylamine: 20 parts. When preparing adhesion promoter B, the above parts by weight of 3-(acryloyloxy)propyltrimethoxysilane and benzylamine are added to a reaction kettle, the temperature is set at 95°C-105°C, and the reaction is carried out for 2-2.5 hours; then TDI is added, the temperature is set at 25-35°C, the reaction is heated for 3-3.5 hours, and the heating is stopped to obtain adhesion promoter B.

[0067] The preparation method of component B is as follows: adding isocyanate, adhesion promoter A and adhesion promoter B in a closed reaction kettle according to weight parts; setting the stirring speed to 45-55r / min, stirring for 35-45min, and obtaining component B.

[0068] First, bio-based polyols 1#-3# are prepared.

[0069] Add 63 parts of castor oil, 1 part of 4,4,-dicyclohexylmethanediamine and 23 parts of bio-based glycerol into a four-necked bottle equipped with a thermometer and a distillation device and capable of being evacuated, stir at 180°C for 2 hours, then maintain at 210°C for 3 hours, and then cool to 120°C; then add 13 parts of adipic acid, set the temperature to 190°C, evacuate, set the vacuum degree to 0.9, then gradually increase the temperature to 230°C, maintain for 2 hours, test the acid value to be less than 10 mgKOH / g, stop heating, and obtain bio-based polyol 1#.

[0070] Add 64.5 parts of castor oil, 2 parts of 4,4,-dicyclohexylmethanediamine and 19 parts of bio-based glycerol into a four-necked bottle equipped with a thermometer and a distillation device and capable of being evacuated, stir at 180°C for 2 hours, then maintain at 210°C for 2.5 hours, and then cool to 120°C; then add 14.5 parts of adipic acid, set the temperature to 190°C, evacuate, set the vacuum degree to 0.9, then gradually increase the temperature to 230°C, maintain for 2 hours, test the acid value to be less than 10 mgKOH / g, stop heating, and obtain bio-based polyol 2#.

[0071] Add 68 parts of castor oil, 1.5 parts of 4,4,-dicyclohexylmethanediamine and 20.6 parts of bio-based glycerol into a four-necked bottle equipped with a thermometer and a distillation device and capable of being evacuated, stir at 180°C for 2 hours, then maintain at 210°C for 2.8 hours, and then cool to 120°C; then add 17 parts of adipic acid, set the temperature to 190°C, evacuate, set the vacuum degree to 0.9, then gradually increase the temperature to 230°C, maintain for 2 hours, test the acid value to be less than 10 mgKOH / g, stop heating, and obtain bio-based polyol 3#.

[0072] Secondly, self-catalytic epoxy-modified polyols a#-c# were prepared.

[0073] 45 parts of epoxy resin E-44 and 20 parts of epoxy resin E-51 were added into the reaction kettle, and 25 parts of diethanolamine were added dropwise. After 10 minutes of addition, the temperature was set to 45°C and stirring was continued for 30 minutes. 10 parts of methylethanolamine were added and the temperature was set to 95°C. After heating for 2 hours, self-catalytic epoxy modified polyol a# was obtained.

[0074] 55 parts of epoxy resin E-44 and 15 parts of epoxy resin E-51 were added into the reaction kettle, and 15 parts of diethanolamine were added dropwise. After 15 minutes of addition, the temperature was set to 50°C and stirring was continued for 30 minutes. 15 parts of methylethanolamine were added and the temperature was set to 85°C. After heating for 2 hours, self-catalytic epoxy modified polyol b# was obtained.

[0075] 47 parts of epoxy resin E-44 and 19 parts of epoxy resin E-51 were added into the reaction kettle, and 30 parts of diethanolamine were added dropwise. After 12 minutes of addition, the temperature was set to 48°C, and stirring was continued for 30 minutes. 12 parts of methylethanolamine were added, and the temperature was set to 90°C. After heating for 2 hours, self-catalytic epoxy modified polyol c# was obtained. Example 1

[0076] Step 1) Preparation of component A:

[0077] Add 80 parts of bio-based polyol 1#, 13.6 parts of self-catalytic epoxy modified polyol a#, 1 part of ultraviolet absorber, 2 parts of antioxidant, and 1 part of di(1-hydroxyethyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 300 r / min, and stir for 20 minutes; then add 2 parts of foam stabilizer and 0.4 parts of deionized water, set the stirring speed to 1500 r / min, and high-speed disperse for 30 minutes to obtain component A.

[0078] Step 2) Preparation of component B:

[0079] In a closed reaction kettle, 43.5 parts of polymethylene polyphenyl isocyanate, 43.5 parts of diphenylmethylene diisocyanate, 5 parts of adhesion promoter A and 7 parts of adhesion promoter B were added, the stirring speed was set to 45 r / min, and the mixture was stirred for 45 minutes to obtain component B.

[0080] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0081] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fiber. The mold temperature is maintained at 50°C for 45 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting. Example 2

[0082] Step 1) Preparation of component A:

[0083] Add 70 parts of bio-based polyol 1#, 15 parts of self-catalytic epoxy modified polyol a#, 2 parts of ultraviolet absorber, 1.7 parts of antioxidant, and 3 parts of di(1-hydroxybutyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 200 r / min, and stir for 18 minutes; then add 3 parts of foam stabilizer and 0.3 parts of deionized water, set the stirring speed to 1800 r / min, and high-speed disperse for 30 minutes to obtain component A.

[0084] Step 2) Preparation of component B:

[0085] In a closed reaction kettle, add 60 parts of polymethylene polyphenyl isocyanate, 30 parts of diphenylmethylene diisocyanate, 6 parts of adhesion promoter A and 4 parts of adhesion promoter B, set the stirring speed to 55 r / min, stir for 35 minutes, and obtain component B.

[0086] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0087] The components A and B are heated to 24°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fibers. The mold temperature is maintained at 45°C for 35 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting. Example 3

[0088] Step 1) Preparation of component A:

[0089] Add 76.6 parts of bio-based polyol 1#, 15 parts of self-catalytic epoxy modified polyol a#, 1.4 parts of ultraviolet absorber, 2 parts of antioxidant, and 2.2 parts of di(1-hydroxypropyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 250r / min, and stir for 15 minutes; then add 2.4 parts of foam stabilizer and 0.4 parts of deionized water, set the stirring speed to 1600r / min, and high-speed disperse for 30 minutes to obtain component A.

[0090] Step 2) Preparation of component B:

[0091] In a closed reaction kettle, 54 parts of polymethylene polyphenyl isocyanate, 33.5 parts of diphenylmethylene diisocyanate, 7.5 parts of adhesion promoter A and 5 parts of adhesion promoter B were added, the stirring speed was set to 50 r / min, and the mixture was stirred for 45 minutes to obtain component B.

[0092] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0093] The components A and B are heated to 25°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fibers. The mold temperature is maintained at 48°C for 35 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting. Example 4

[0094] Step 1) Preparation of component A:

[0095] Add 75 parts of bio-based polyol 1#, 13.9 parts of self-catalytic epoxy modified polyol b#, 1.4 parts of ultraviolet absorber, 2 parts of antioxidant, and 2.2 parts of di(1-hydroxypropyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 300 r / min, and stir for 15 minutes; then add 2.4 parts of foam stabilizer and 0.4 parts of deionized water, set the stirring speed to 1700 r / min, and disperse at high speed for 30 minutes to obtain component A.

[0096] Step 2) Preparation of component B:

[0097] In a closed reaction kettle, 52 parts of polymethylene polyphenyl isocyanate were added to mix 35.5 parts of diphenylmethylene diisocyanate, 6.5 parts of adhesion promoter A and 6 parts of adhesion promoter B, and the stirring speed was set to 55 r / min and stirred for 35 minutes to obtain component B.

[0098] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0099] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fibers. The mold temperature is maintained at 50°C for 40 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting. Example 5

[0100] Step 1) Preparation of component A:

[0101] Add 74.6 parts of bio-based polyol 1#, 13 parts of self-catalytic epoxy modified polyol c#, 1.6 parts of ultraviolet absorber, 1.8 parts of antioxidant, and 2.2 parts of di(1-hydroxypropyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 200 r / min, and stir for 20 minutes; then add 1 part of foam stabilizer and 0.2 parts of deionized water, set the stirring speed to 1800 r / min, and disperse at high speed for 30 minutes to obtain component A.

[0102] Step 2) Preparation of component B:

[0103] In a closed reaction kettle, 53 parts of polymethylene polyphenyl isocyanate, 34.5 parts of diphenylmethylene diisocyanate, 5.8 parts of adhesion promoter A and 6.7 parts of adhesion promoter B were added, the stirring speed was set to 55 r / min, and the mixture was stirred for 45 minutes to obtain component B.

[0104] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0105] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fiber. The mold temperature is maintained at 50°C for 42 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting. Example 6

[0106] Step 1) Preparation of component A:

[0107] Add 73.6 parts of bio-based polyol 2#, 14.7 parts of self-catalytic epoxy modified polyol a#, 1.8 parts of ultraviolet absorber, 1 part of antioxidant, and 2.2 parts of di(1-hydroxyethyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 280 r / min, and stir for 18 minutes; then add 2.1 parts of foam stabilizer and 0.3 parts of deionized water, set the stirring speed to 1800 r / min, and high-speed disperse for 30 minutes to obtain component A.

[0108] Step 2) Preparation of component B:

[0109] In a closed reaction kettle, 47 parts of polymethylene polyphenyl isocyanate, 43 parts of diphenylmethylene diisocyanate, 5.5 parts of adhesion promoter A and 4.5 parts of adhesion promoter B were added, the stirring speed was set to 55 r / min, and the mixture was stirred for 35 minutes to obtain component B.

[0110] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0111] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fibers. The mold temperature is maintained at 50°C for 40 minutes. The components are compression molded and cut to obtain a recyclable bio-based flame-retardant composite sleeper. Example 7

[0112] Step 1) Preparation of component A:

[0113] Add 73.6 parts of bio-based polyol 2#, 13 parts of self-catalytic epoxy modified polyol b#, 1.7 parts of ultraviolet absorber, 2 parts of antioxidant, and 1.7 parts of di(1-hydroxyethyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 300 r / min, and stir for 15 minutes; then add 3 parts of foam stabilizer and 0.4 parts of deionized water, set the stirring speed to 1800 r / min, and high-speed disperse for 30 minutes to obtain component A.

[0114] Step 2) Preparation of component B:

[0115] In a closed reaction kettle, 57 parts of polymethylene polyphenyl isocyanate, 31 parts of diphenylmethylene diisocyanate, 6.5 parts of adhesion promoter A and 5.5 parts of adhesion promoter B were added, the stirring speed was set to 45 r / min, and the mixture was stirred for 45 minutes to obtain component B.

[0116] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0117] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fiber. The mold temperature is maintained at 50°C for 45 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting. Example 8

[0118] Step 1) Preparation of component A:

[0119] Add 76.9 parts of bio-based polyol 2#, 14.4 parts of self-catalytic epoxy modified polyol c#, 1.7 parts of ultraviolet absorber, 1.6 parts of antioxidant, and 3 parts of di(1-hydroxybutyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 200 r / min, and stir for 20 minutes; then add 2 parts of foam stabilizer and 0.4 parts of deionized water, set the stirring speed to 1800 r / min, and high-speed disperse for 30 minutes to obtain component A.

[0120] Step 2) Preparation of component B:

[0121] In a closed reaction kettle, 53.5 parts of polymethylene polyphenyl isocyanate, 35.5 parts of diphenylmethylene diisocyanate, 6.5 parts of adhesion promoter A and 4.5 parts of adhesion promoter B were added, the stirring speed was set to 55 r / min, and the mixture was stirred for 35 minutes to obtain component B.

[0122] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0123] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fibers. The mold temperature is maintained at 50°C for 40 minutes. The components are compression molded and cut to obtain a recyclable bio-based flame-retardant composite sleeper. Example 9

[0124] Step 1) Preparation of component A:

[0125] Add 76.9 parts of bio-based polyol 3#, 14.4 parts of self-catalytic epoxy modified polyol a#, 1.7 parts of ultraviolet absorber, 1.6 parts of antioxidant, and 3 parts of di(1-hydroxybutyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 300 r / min, and stir for 15 minutes; then add 2 parts of foam stabilizer and 0.4 parts of deionized water, set the stirring speed to 1800 r / min, and high-speed disperse for 30 minutes to obtain component A.

[0126] Step 2) Preparation of component B:

[0127] In a closed reaction kettle, 50.5 parts of polymethylene polyphenyl isocyanate, 37.5 parts of diphenylmethylene diisocyanate, 5.5 parts of adhesion promoter A and 6.5 parts of adhesion promoter B were added, the stirring speed was set to 55 r / min, and the mixture was stirred for 35 minutes to obtain component B.

[0128] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0129] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fiber. The mold temperature is maintained at 50°C for 35 minutes. The components are compression molded and cut to obtain a recyclable bio-based flame-retardant composite sleeper. Example 10

[0130] Step 1) Preparation of component A:

[0131] Add 78.9 parts of bio-based polyol 3#, 13.2 parts of self-catalytic epoxy modified polyol b#, 1.8 parts of ultraviolet absorber, 1.8 parts of antioxidant, and 1.6 parts of di(1-hydroxyethyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 300 r / min, and stir for 15 minutes; then add 2.5 parts of foam stabilizer and 0.2 parts of deionized water, set the stirring speed to 1800 r / min, and disperse at high speed for 30 minutes to obtain component A.

[0132] Step 2) Preparation of component B:

[0133] In a closed reaction kettle, 59 parts of polymethylene polyphenyl isocyanate were added to mix 30.1 parts of diphenylmethylene diisocyanate, 5.8 parts of adhesion promoter A and 5.1 parts of adhesion promoter B, and the stirring speed was set to 55 r / min and stirred for 45 minutes to obtain component B.

[0134] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0135] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fiber. The mold temperature is maintained at 50°C for 45 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting. Embodiment 11

[0136] Step 1) Preparation of component A:

[0137] Add 78.9 parts of bio-based polyol 3#, 13.2 parts of self-catalytic epoxy modified polyol c#, 1.8 parts of ultraviolet absorber, 1.8 parts of antioxidant, and 1.6 parts of di(1-hydroxyethyl) diselenide into a high-speed dispersion kettle, set the stirring speed to 300 r / min, and stir for 15 minutes; then add 2.5 parts of foam stabilizer and 0.2 parts of deionized water, set the stirring speed to 1800 r / min, and disperse at high speed for 30 minutes to obtain component A.

[0138] Step 2) Preparation of component B:

[0139] In a closed reaction kettle, 57.1 parts of polymethylene polyphenyl isocyanate, 32.5 parts of diphenylmethylene diisocyanate, 5.3 parts of adhesion promoter A and 5.1 parts of adhesion promoter B were added, the stirring speed was set to 55 r / min, and the mixture was stirred for 45 minutes to obtain component B.

[0140] Step 3) Preparation of recyclable bio-based flame retardant composite sleepers:

[0141] The components A and B are heated to 26°C in independent material pipes respectively, and then the components A and B are mixed evenly and injected into a mold with long glass fiber. The mold temperature is maintained at 50°C for 45 minutes. A recyclable bio-based flame-retardant composite sleeper is obtained by compression molding and cutting.

[0142] Comparative Example 1

[0143] The di(1-hydroxybutyl) diselenide was replaced with TPCC, and the other raw materials, components and preparation method were the same as those in Example 2.

[0144] Comparative Example 2

[0145] The bio-based polyol was replaced with polyether polyol 303F, and the other raw materials, components and preparation method were the same as those in Example 2.

[0146] Comparative Example 3

[0147] 70 parts of bio-based polyol 1# and 20 parts of self-catalytic epoxy-modified polyol a# were replaced with 89.8 parts of bio-based polyol, 0.1 parts of catalyst NX-100 and 0.1 parts of catalyst 8002. Other raw materials, components and preparation methods were the same as those in Example 2.

[0148] Comparative Example 4

[0149] The adhesion promoter A was replaced by KH-560, and the adhesion promoter B was replaced by 3-(acryloxy)propyltrimethoxysilane. The other raw materials, components and preparation methods were the same as those in Example 2.

[0150] Performance Testing

[0151] The recyclable bio-based composite sleepers obtained in Examples 1-11 and Comparative Examples 1-4 were subjected to performance testing, and the performance testing basis is as follows:

[0152] According to GB / T 1448 fiber reinforced plastic compression performance test;

[0153] According to GB / T 1449 fiber reinforced plastic bending performance test;

[0154] According to GB / T 1450.1 fiber reinforced plastic interlaminar shear strength test;

[0155] According to GB / T 2573 fiber reinforced plastic aging performance test;

[0156] According to GB / T 2408 plastic combustion performance test horizontal method and vertical method.

[0157] The test data are shown in Table 1.

[0158] Table 1

[0159]

[0160] From the test data of Examples 1-11 in Table 1, it can be seen that component A of the composite sleeper is prepared by compounding homemade bio-based polyols, self-catalytic epoxy polyols and diselenide diols, mixed with component B and then pultruded with glass fiber. The measured bending modulus is greater than 15 GPa, the bending strength is greater than 230 MPa, the shear strength is greater than 21 MPa, and the compressibility is greater than 130 MPa. The bending modulus, bending strength, shear strength and other properties after aging are all above 95% of the strength before aging, and the flame retardant grade reaches V1 level, which is higher than HB level, meeting the standard requirements.

[0161] Comparison of flame retardant performance results: In Examples 1-11, di(1-hydroxyethyl) diselenide, di(1-hydroxypropyl) diselenide, and di(1-hydroxybutyl) diselenide were used as small molecule polyurethane chain extenders, which not only improved the mechanical properties of the composite sleeper, but also improved its flame retardancy. Compared with Example 2, the mechanical properties of Comparative Example 1 were lower than those of Example 2, and the aging resistance of Comparative Example 1 was also significantly reduced, and the fire rating was reduced to HB, indicating that di(1-hydroxyethyl) diselenide was used as a polyurethane chain extender to increase the hard segment content and improve the mechanical properties of the composite sleeper. At the same time, since the diselenide bonds of diselenide polyols can capture free radicals and play a chain termination role, the flame retardancy and weather resistance of the composite sleeper were improved. In Examples 6-11, the types and amounts of bio-based polyols and self-catalytic epoxy-modified polyols were adjusted to perform pultrusion tests, and composite sleepers with high mechanical strength and excellent fire retardancy were obtained.

[0162] Comparison of mechanical properties: Compared with Example 2, the mechanical properties of Comparative Example 2 are significantly lower than those of Example 2. Compared with Examples 3, 4, and 5, the mechanical properties of Example 4 are better than those of Examples 5 and 3. This is because the prepared bio-based polyol contains ester bonds and amide groups with large cohesive force, which improves the mechanical properties of the material. The weather resistance of Example 2 is better than that of Comparative Example 2. This is because the main chain of the bio-based polyol is stable and contains side groups, which can improve the aging resistance of the material. The CH bonds in the methylene groups connected to the ether bonds in the polyether polyol in Comparative Example 2 are more active, and react with oxygen to break the chain when exposed to ultraviolet light, causing the material to pulverize and reduce the mechanical properties of the material.

[0163] Comparison of self-catalytic effect: Compared with Example 2, the mechanical property strength of Comparative Example 3, Example 1, and Example 3 is Example 2, Example 3, and Example 1 Comparative Example 3, respectively, which shows that the self-catalytic epoxy modified polyol can not only play a catalytic effect, but also improve the mechanical strength of the material. This is because the self-catalytic epoxy polyol contains a benzene ring with strong cohesive force, and after reacting with isocyanate, it forms a hard segment, which is more easily aggregated into an island structure as a physical cross-linking point, thereby improving the mechanical strength; the tertiary amine contained in the self-catalytic epoxy polyol can be used as a catalyst for the reaction of isocyanate with polyols and water, and therefore has a self-catalytic effect.

[0164] Strength effect comparison: The mechanical properties of comparative example 4 are lower than those of example 2. This is because the silane in the homemade adhesion promoter A and adhesion promoter B can react with the hydroxyl group on the surface of the glass fiber, and the isocyanate group can participate in the overall curing of the resin, thereby improving the overall mechanical properties of the sleeper.

[0165] From the above data analysis, it can be seen that the composite sleeper material obtained by compounding homemade bio-based polyols, self-catalytic epoxy-modified polyols and diselenide diols with isocyanate and adhesion promoter is pultruded to obtain recyclable bio-based flame-retardant composite sleepers, which not only have high mechanical strength but also excellent fire resistance.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A recyclable bio-based flame-retardant composite sleeper, characterized by: The raw materials of the composite sleeper are long glass fiber and component A and component B in a mass ratio of 1:1; The A component includes the following components in parts by weight: Bio-based polyols: 70-80 parts; Self-catalytic epoxy modified polyol: 10-15 parts; Ultraviolet absorber: 1-2 parts; Antioxidant: 1-2 parts; Foam stabilizer: 1-3 parts; Diselendiol: 1-3 parts; Deionized water: 0.2-0.4 parts; The B component includes the following components in parts by weight: Isocyanate: 87-90 parts; Adhesion promoter A: 5-7.5 parts; Adhesion promoter B: 4-7 parts; The bio-based polyol is prepared from the following raw materials in parts by weight: castor oil: 63-68 parts; 4,4,-dicyclohexylmethanediamine: 1-2 parts; bio-based glycerol: 19-23 parts; Adipic acid: 13-17 parts; when preparing bio-based polyols, castor oil, 4,4-dicyclohexylmethanediamine, and bio-based glycerol in the above weight parts are added into a four-necked bottle equipped with a thermometer and a distillation device and can be evacuated, stirred at 180°C for 2 hours, then heated to 210°C and maintained for 2.5-3 hours, and then cooled to 120°C and adipic acid is added; the temperature is set to 190°C, evacuated, the vacuum degree is set to 0.9, and then gradually heated to 230°C and maintained for 2 hours. When the acid value is tested to be less than 10 mgKOH / g, heating is stopped to obtain bio-based polyols; The self-catalytic epoxy-modified polyol is prepared from the following raw materials in parts by weight: epoxy resin E-44: 45-55 parts; epoxy resin E-51: 15-20 parts; diethanolamine: 15-30 parts; methylethanolamine: 10-15 parts; when preparing the self-catalytic epoxy-modified polyol, the above-mentioned parts by weight of epoxy resin E-44 and epoxy resin E-51 are added into a reaction kettle, and diethanolamine is added dropwise. After 10-15 minutes of dropwise addition, the temperature is set at 45-50°C, stirring is continued for 30 minutes, and then methylethanolamine is added, the temperature is set at 85-95°C, and heating is performed for 2 hours to obtain the self-catalytic epoxy-modified polyol; The adhesion promoter A in the B component is prepared from the following raw materials in parts by weight: TDI: 35 parts; KH-560: 45 parts; methylbenzylamine: 30 parts; when preparing the adhesion promoter A, the above parts by weight of KH-560 and methylbenzylamine are added into a reaction kettle, the temperature is set at 95°C-105°C, the reaction is carried out for 2-2.5 hours, TDI is added and the temperature is set at 55-65°C, the reaction is heated for 3-3.5 hours, and the heating is stopped to obtain the adhesion promoter A; The adhesion promoter B in the B component is prepared from the following raw materials in parts by weight: TDI: 34 parts; 3-(acryloxy)propyltrimethoxysilane: 46 parts; benzylamine: 20 parts; when preparing the adhesion promoter B, the above parts by weight of 3-(acryloxy)propyltrimethoxysilane and benzylamine are added into a reaction kettle, the temperature is set at 95° C.-105° C., and the reaction is carried out for 2-2.5 hours; then TDI is added, the temperature is set at 25-35° C., the reaction is heated for 3-3.5 hours, and the heating is stopped to obtain the adhesion promoter B; The content of long glass fibers in the composite sleeper is 65-67%.

2. The recyclable bio-based flame-retardant composite sleeper according to claim 1, characterized in that: The ultraviolet absorber is at least one of BASF Uvinul3050, BASF UV327 or Jinan Xiangfeng Weiye Chemical Co., Ltd. UV531; the antioxidant is BASF Irganox 1010; The foam stabilizer is at least one of Meside M-8805, Shanghai Baiang Chemical BA-9738 or Jining Huakai Resin HK-314.

3. The recyclable bio-based flame-retardant composite sleeper according to claim 1, characterized in that: The diselendiol is a mixture of one or more of bis(1-hydroxyethyl) diselenide, bis(1-hydroxypropyl) diselenide and bis(1-hydroxybutyl) diselenide.

4. The recyclable bio-based flame-retardant composite sleeper according to claim 1, characterized in that: The preparation method of the component A is as follows: add the bio-based polyol, the self-catalytic epoxy-modified polyol, the ultraviolet absorber, the antioxidant, and the diselenide diol into a high-speed dispersion kettle according to weight proportions, set the stirring speed to 200-300 r / min, and stir for 15-20 min; Then add foam stabilizer and deionized water, set the stirring speed to 1500-1800 r / min, and disperse at high speed for 30 minutes to obtain component A.

5. The recyclable bio-based flame-retardant composite sleeper according to claim 1, characterized in that: The preparation method of the B component is as follows: adding isocyanate, adhesion promoter A and adhesion promoter B in a closed reaction kettle according to weight parts; setting the stirring speed to 45-55 r / min, stirring for 35-45 minutes, and obtaining the B component.

6. A method for preparing the recyclable bio-based flame-retardant composite sleeper according to any one of claims 1 to 5, characterized in that: The specific steps include: Component A and component B are heated to 24-26°C in independent material pipes respectively, and then mixed and evenly injected into a mold with long glass fiber. The mold temperature is maintained at 45-50°C for 35-45 minutes; compression molding and cutting are performed to obtain recyclable bio-based flame-retardant composite sleepers.

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