A wear-resistant glass fiber reinforced plastic manhole cover containing polyester and preparation method thereof

Abstract

The invention relates to the technical field of glass fiber reinforced plastic manhole covers, and discloses a wear-resistant glass fiber reinforced plastic manhole cover containing polyester and a preparation method thereof. The phosphorus compound in the flame-retardant and heat-resistant unsaturated polyester is first decomposed into phosphoric acid by heat during combustion, and then dehydrated to generate pyrophosphoric acid, and then metaphosphoric acid and polymetaphosphoric acid are generated, which can promote the dehydration of the unsaturated polyester into carbon, and effectively prevent the matrix from being oxidized and decomposed; the nitrogen compound mainly plays a gas phase flame retardant role, and can generate a large amount of non-flammable gases such as nitrogen and ammonia during combustion, which plays a role in diluting combustible gases such as oxygen; the fluorine-containing group in the flame-retardant and heat-resistant unsaturated polyester can form a fluorine-metal compound on the sliding glass fiber reinforced plastic surface, which has a good lubricating effect and is helpful to improve the wear resistance; the unsaturated polyester introduces a twisted and non-coplanar diazonium ketone biphenyl structure, the molecular chain has high rigidity, the heat resistance of the material is improved, and the application field of the glass fiber reinforced plastic manhole cover is further broadened.

Description

Technical Field

[0001] The invention relates to the technical field of glass fiber reinforced plastic manhole covers, in particular to a wear-resistant glass fiber reinforced plastic manhole cover containing polyester and a preparation method thereof. Background Art

[0002] At present, most of the manhole covers of sewage desilting wells, tap water, telecommunications and other facilities in urban roads and residential areas are made of cast iron and cement concrete. These materials are often easily stolen or crushed by heavy vehicles, thus forming a terrible urban "black hole", seriously affecting traffic and personal safety; FRP is a new type of engineering structural material with unsaturated resin as the matrix and glass fiber and its products as the reinforcing material. FRP manhole covers are new manhole covers developed to solve the defects of steel and iron manhole covers that are easy to rust and lose, bulky, and easy to crack, and to improve their use functions and economic and social benefits. They have the advantages of light weight and high strength, but their heat resistance is poor, and they are extremely easy to burn under certain conditions, often accompanied by the generation of thick smoke, toxic gases, etc., thus causing fires. Therefore, the preparation of a flame-resistant and heat-resistant FRP manhole cover has become a problem that needs to be solved urgently.

[0003] At present, most of the flame retardant modification of FRP manhole covers uses halogen flame retardants, but the introduction of halogen reduces the UV resistance of the flame retardant body material, and produces a large amount of smoke and corrosive toxic gases during combustion, posing a serious threat to the environment and human life safety; manhole covers are placed outdoors, and they must withstand the impact of car rolling, exposure to sunlight, and erosion by rain. At the same time, the manhole covers must also consider indicators such as wear resistance and skid resistance. However, the existing FRP manhole covers have the problem of poor wear resistance. Generally, nano fillers such as montmorillonite and diatomaceous earth are added, but these nano fillers have poor compatibility with unsaturated resins, and a large amount needs to be added to achieve obvious effects.

[0004] In order to improve the high temperature resistance of FRP manhole covers, the present invention aims to achieve this by introducing a heat-resistant and flame-resistant structure, introducing a molecular structure of a fluorine-phosphorus-nitrogen heterocycle into unsaturated polyester, preparing a modified unsaturated polyester resin having excellent flame retardant, heat-resistant and wear-resistant properties, and compounding it with glass fiber, etc., and curing and forming it in a mold, thereby broadening the use scope and application field of FRP manhole covers. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a wear-resistant fiberglass manhole cover containing polyester and a preparation method thereof, thereby enhancing the flame retardant, heat resistance and wear resistance of the fiberglass manhole cover and broadening its further application field.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A polyester-containing wear-resistant glass fiber reinforced plastic manhole cover comprises the following components in parts by weight: 30-50 parts of flame-retardant and heat-resistant unsaturated polyester, 15-25 parts of quartz sand, 25-40 parts of glass fiber, 5-10 parts of light calcium carbonate, 3-5 parts of active magnesium oxide, 1-3 parts of antioxidant, 2-6 parts of low-temperature shrinkage agent, 0.5-2 parts of internal release agent and 0.01-0.03 parts of cyclohexanone peroxide.

[0008] The preparation method of flame retardant and heat resistant unsaturated polyester is as follows: under nitrogen atmosphere, 1,3-propylene glycol and a structural formula of Fluorine-containing phosphorus and nitrogen heterocyclic dicarboxylic acid, phthalic anhydride, maleic anhydride and o-xylene are reacted at 140-160°C for 3-8h, cooled to 100-115°C, hydroquinone, benzoyl peroxide and styrene are added, and stirred evenly at 120-135°C to obtain a flame-retardant and heat-resistant unsaturated polyester.

[0009] Preferably, the low temperature shrinkage agent is any one of polystyrene, polyethylene or polyvinyl acetate.

[0010] Preferably, the internal release agent is any one of alkyl phosphatidic acid, stearate or lecithin.

[0011] Preferably, the ratio of 1,3-propylene glycol, fluorine-containing phosphorus and nitrogen heterocyclic dicarboxylic acid, phthalic anhydride, maleic anhydride, hydroquinone, benzoyl peroxide and styrene is 100g:(35-175)g:(60-75)g:(35-50)g:(10-15)g:(3-6)g:(60-75)g.

[0012] Preferably, the preparation method of the fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid is:

[0013] Step (1), under a nitrogen atmosphere, add 6-bromo-2,3-phthalazinone, tetrakis(triphenylphosphine)palladium and toluene to a reaction flask, stir evenly, add 3-carboxy-5-fluorophenylboric acid and potassium phosphate, stir to react, after the reaction is completed, extract with ethyl acetate and deionized water, concentrate the organic phase, and separate by column chromatography to obtain 3-carboxy-5-fluorophenylphthalazinone.

[0014] Step (2), under a nitrogen atmosphere, add phenylphosphonyl dichloride and N,N-dimethylacetamide to a reaction flask, stir evenly, add 3-carboxy-5-fluorophenylphthalazinone and potassium carbonate, react at 130-150° C. for 5-12 h, filter while hot, cool and crystallize, wash with ethanol, and dry to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid.

[0015] Preferably, in step (1), the ratio of 6-bromo-2,3-phthalazinone, tetrakis(triphenylphosphine)palladium, 3-carboxy-5-fluorophenylboric acid and potassium phosphate is 1 mol:(0.02-0.05) mol:(1.05-1.2) mol:(1.5-2) mol.

[0016] Preferably, in step (1), the reaction temperature is 90-105° C. and the reaction time is 12-24 h.

[0017] Preferably, in step (2), the ratio of phenylphosphonyl dichloride, 3-carboxy-5-fluorophenylphthalazinone, and potassium carbonate is 1 mol: (2.1-2.3) mol: (2.4-2.8) mol.

[0018] Preferably, the preparation method is: evenly laying the glass fiber in the cavity of the manhole cover molding mold, adding evenly mixed flame retardant and heat-resistant unsaturated resin, quartz sand, light calcium carbonate and active magnesium oxide, and then heating at 80-100°C for 10-20 minutes, adding antioxidant, low-temperature shrinkage agent, internal release agent and cyclohexanone peroxide, closing the film and pressurizing, hot pressing at 140-160°C, opening the mold and trimming, to obtain a wear-resistant fiberglass manhole cover containing polyester.

[0019] Preferably, the pressure of the membrane closing pressurization is 60-80 MPa.

[0020] By adopting the above technical solution, the beneficial effects of the present invention are:

[0021] The invention firstly utilizes 6-bromo-2,3-phthalazinone and 3-carboxyl-5-fluorophenylboric acid to undergo a coupling reaction under the action of tetrakis(triphenylphosphine)palladium and potassium phosphate to obtain 3-carboxyl-5-fluorophenylphthalazinone, then undergoes a substitution reaction with phenylphosphine dichloride to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid, and then polymerizes with phthalic anhydride, 1,3-propylene glycol, etc. to obtain a flame-retardant and heat-resistant unsaturated polyester, and finally adds glass fiber and other additives, and obtains a polyester-containing wear-resistant glass fiber reinforced plastic manhole cover after curing and molding.

[0022] Flame-retardant and heat-resistant unsaturated polyester contains phosphorus-nitrogen synergistic flame-retardant elements. Phosphorus compounds first decompose into phosphoric acid when heated during combustion, then lose water to form pyrophosphoric acid, and then form metaphosphoric acid and polymetaphosphoric acid. These acids can promote the dehydration of unsaturated polyester into carbon, and effectively prevent the matrix from being oxidized and decomposed. Nitrogen compounds mainly play a gas phase flame retardant role. When burned, they can produce a large amount of non-combustible gases such as nitrogen and ammonia, capture free radicals produced by the thermal decomposition of the material, and play a role in diluting combustible gases such as oxygen. The synergistic flame retardancy of nitrogen and phosphorus significantly improves the flame retardant properties of FRP materials.

[0023] The glass fiber itself has good wear resistance, which makes the material surface rough, increases the relative motion resistance of the friction interface, and improves wear resistance. It is wrapped and coated with the unsaturated resin in a mesh shape, which plays a supporting role in the process of friction and wear. The fluorine-containing groups in the flame retardant and heat-resistant unsaturated polyester can form fluorine-metal compounds on the sliding surface of FRP, which has good lubrication and helps to improve wear resistance to prevent severe friction and wear. The prepared flame retardant and heat-resistant unsaturated polyester molecular chain is spiral, which is beneficial to further reduce the friction between the molecular chains and increase the service life of the FRP manhole cover.

[0024] The unsaturated polyester of the FRP manhole cover introduces a twisted, non-coplanar phthalazinone biphenyl structure, which makes the molecular chain rigid and makes it easy for the unsaturated polyester to entangle the molecular chain, thus resisting external forces, improving the heat resistance of the material, and further broadening the application areas of the FRP manhole cover. DETAILED DESCRIPTION

[0025] In order to further understand the present invention, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] 6-Bromo-2,3-phthalazinone, CAS number is 75884-70-7.

[0027] 3-Carboxy-5-fluorophenylboronic acid, CAS number is 871329-84-9.

[0028] Phenylphosphonic acid dichloride, CAS number is 824-72-6.

[0029] Phthalic anhydride, CAS number is 85-44-9.

[0030] Maleic anhydride, CAS number is 110-16-7.

[0031] Example 1

[0032] (1) Under nitrogen atmosphere, 45 mmol of 6-bromo-2,3-phthalazinone, 1.62 mmol of tetrakis(triphenylphosphine)palladium and 360 mL of toluene were added to a reaction flask, and after stirring evenly, 50.4 mmol of 3-carboxy-5-fluorophenylboric acid and 75.6 mmol of potassium phosphate were added, and the mixture was reacted at 100° C. for 16 h, extracted with ethyl acetate and deionized water, and the organic phase was concentrated and separated by column chromatography to obtain 3-carboxy-5-fluorophenylphthalazinone. The preparation reaction formula is as follows:

[0033]

[0034] (2) Under nitrogen atmosphere, add 40 mmol of phenylphosphonyl dichloride and 500 mL of N,N-dimethylacetamide to a reaction flask, stir evenly, add 88 mmol of 3-carboxy-5-fluorophenylphthalazinone and 105 mmol of potassium carbonate, react at 140° C. for 8 h, filter while hot, cool and crystallize, wash with ethanol, and dry to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid. The preparation reaction formula is as follows:

[0035]

[0036] (3) Under a nitrogen atmosphere, 100 g of 1,3-propylene glycol, 35 g of fluorine-containing phosphorus-nitrogen heterocyclic dicarboxylic acid, 65 g of phthalic anhydride, 40 g of maleic anhydride and 800 mL of o-xylene were added to a reaction flask, and the mixture was reacted at 150° C. for 5 h. The mixture was cooled to 110° C., 12 g of hydroquinone, 4 g of benzoyl peroxide and 70 g of styrene were added, and the mixture was stirred evenly at 125° C. to obtain a flame-retardant and heat-resistant unsaturated polyester.

[0037] (4) 30 g of glass fiber was evenly laid in the mold cavity of the manhole cover molding mold, and 30 g of flame retardant and heat-resistant unsaturated resin, 20 g of quartz sand, 8 g of light calcium carbonate and 4 g of active magnesium oxide were added and then heated at 90 ° C for 15 min, 2 g of antioxidant 1010, 5 g of polystyrene, 0.15 g of alkyl phosphatidic acid and 0.02 g of cyclohexanone peroxide were added, the combined film was pressurized to 70 MPa, and hot-pressed at 155 ° C. The mold was opened and trimmed to obtain a wear-resistant fiberglass manhole cover containing polyester.

[0038] Example 2

[0039] (1) Under nitrogen atmosphere, 80 mmol of 6-bromo-2,3-phthalazinone, 1.6 mmol of tetrakis(triphenylphosphine)palladium and 400 mL of toluene were added to a reaction flask, and after stirring evenly, 84 mmol of 3-carboxy-5-fluorophenylboric acid and 120 mmol of potassium phosphate were added, and the mixture was reacted at 105° C. for 12 h. The mixture was extracted with ethyl acetate and deionized water, and the organic phase was concentrated and separated by column chromatography to obtain 3-carboxy-5-fluorophenylphthalazinone.

[0040] (2) Under a nitrogen atmosphere, 75 mmol of phenylphosphonyl dichloride and 750 mL of N,N-dimethylacetamide were added to a reaction flask, and after stirring, 157.5 mmol of 3-carboxy-5-fluorophenylphthalazinone and 180 mmol of potassium carbonate were added, and the mixture was reacted at 150° C. for 5 h. The mixture was filtered while hot, cooled for crystallization, washed with ethanol, and dried to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid.

[0041] (3) Under a nitrogen atmosphere, 100 g of 1,3-propylene glycol, 70 g of fluorine-containing phosphorus-nitrogen heterocyclic dicarboxylic acid, 60 g of phthalic anhydride, 50 g of maleic anhydride and 750 mL of o-xylene were added to a reaction flask, and the mixture was reacted at 160° C. for 3 h. The temperature was lowered to 115° C., 10 g of hydroquinone, 3 g of benzoyl peroxide and 60 g of styrene were added, and the mixture was stirred evenly at 135° C. to obtain a flame-retardant and heat-resistant unsaturated polyester.

[0042] (4) 25 g of glass fiber was evenly laid in the mold cavity of the manhole cover molding mold, and 35 g of flame retardant and heat-resistant unsaturated resin, 25 g of quartz sand, 5 g of light calcium carbonate and 3 g of active magnesium oxide were added and then heated at 100 ° C for 10 min, 1 g of antioxidant 1010, 2 g of polyethylene, 0.05 g of stearate and 0.01 g of cyclohexanone peroxide were added, the combined film was pressurized to 80 MPa, and hot-pressed at 160 ° C. The mold was opened and trimmed to obtain a wear-resistant fiberglass manhole cover containing polyester.

[0043] Example 3

[0044] (1) Under a nitrogen atmosphere, 30 mmol of 6-bromo-2,3-phthalazinone, 1.5 mmol of tetrakis(triphenylphosphine)palladium and 300 mL of toluene were added to a reaction flask, and after stirring evenly, 36 mmol of 3-carboxy-5-fluorophenylboric acid and 60 mmol of potassium phosphate were added, and the mixture was reacted at 90° C. for 24 h. The mixture was extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, 3-carboxy-5-fluorophenylphthalazinone was obtained.

[0045] (2) Under a nitrogen atmosphere, 25 mmol of phenylphosphonyl dichloride and 375 mL of N,N-dimethylacetamide were added to a reaction flask, and after stirring, 57.5 mmol of 3-carboxy-5-fluorophenylphthalazinone and 70 mmol of potassium carbonate were added, and the mixture was reacted at 130° C. for 12 h. The mixture was filtered while hot, cooled for crystallization, washed with ethanol, and dried to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid.

[0046] (3) Under a nitrogen atmosphere, 100 g of 1,3-propylene glycol, 105 g of fluorine-containing phosphorus-nitrogen heterocyclic dicarboxylic acid, 75 g of phthalic anhydride, 35 g of maleic anhydride and 900 mL of o-xylene were added to a reaction flask, and the mixture was reacted at 140° C. for 8 h. The mixture was cooled to 100° C., 15 g of hydroquinone, 6 g of benzoyl peroxide and 75 g of styrene were added, and the mixture was stirred evenly at 130° C. to obtain a flame-retardant and heat-resistant unsaturated polyester.

[0047] (4) 40 g of glass fiber was evenly laid in the mold cavity of the manhole cover molding mold, and 40 g of flame retardant and heat-resistant unsaturated resin, 15 g of quartz sand, 10 g of light calcium carbonate and 5 g of active magnesium oxide were added and then heated at 80 ° C for 20 min, 3 g of antioxidant 1010, 6 g of polyvinyl acetate, 2 g of lecithin and 0.03 g of cyclohexanone peroxide were added, the combined film was pressurized to 60 MPa, and hot-pressed at 140 ° C. The mold was opened and trimmed to obtain a wear-resistant fiberglass manhole cover containing polyester.

[0048] Example 4

[0049] (1) Under nitrogen atmosphere, 50 mmol of 6-bromo-2,3-phthalazinone, 1.25 mmol of tetrakis(triphenylphosphine)palladium and 450 mL of toluene were added to a reaction flask, and after stirring, 56 mmol of 3-carboxy-5-fluorophenylboric acid and 80 mmol of potassium phosphate were added, and the mixture was reacted at 95° C. for 15 h. The mixture was extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, 3-carboxy-5-fluorophenylphthalazinone was obtained.

[0050] (2) Under a nitrogen atmosphere, 40 mmol of phenylphosphonyl dichloride and 500 mL of N,N-dimethylacetamide were added to a reaction flask, and after stirring, 85 mmol of 3-carboxy-5-fluorophenylphthalazinone and 105 mmol of potassium carbonate were added, and the mixture was reacted at 145° C. for 8 h. The mixture was filtered while hot, cooled for crystallization, washed with ethanol, and dried to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid.

[0051] (3) Under a nitrogen atmosphere, 100 g of 1,3-propylene glycol, 140 g of fluorine-containing phosphorus-nitrogen heterocyclic dicarboxylic acid, 65 g of phthalic anhydride, 45 g of maleic anhydride and 850 mL of o-xylene were added to a reaction flask, and the mixture was reacted at 155° C. for 5 h. The temperature was lowered to 105° C., 12 g of hydroquinone, 4 g of benzoyl peroxide and 70 g of styrene were added, and the mixture was stirred evenly at 130° C. to obtain a flame-retardant and heat-resistant unsaturated polyester.

[0052] (4) 35 g of glass fiber was evenly laid in the mold cavity of the manhole cover molding mold, and 45 g of flame retardant and heat-resistant unsaturated resin, 22 g of quartz sand, 8 g of light calcium carbonate and 5 g of active magnesium oxide were added and then heated at 90 ° C for 15 min, 2 g of antioxidant 1010, 4.5 g of polystyrene, 1.35 g of alkyl phosphatidic acid and 0.025 g of cyclohexanone peroxide were added, the combined film was pressurized to 75 MPa, and hot-pressed at 145 ° C. The mold was opened and trimmed to obtain a wear-resistant fiberglass manhole cover containing polyester.

[0053] Example 5

[0054] (1) Under nitrogen atmosphere, 20 mmol of 6-bromo-2,3-phthalazinone, 0.7 mmol of tetrakis(triphenylphosphine)palladium and 135 mL of toluene were added to a reaction flask, and after stirring, 22.5 mmol of 3-carboxy-5-fluorophenylboric acid and 33 mmol of potassium phosphate were added, and the mixture was reacted at 100° C. for 24 h. The mixture was extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, 3-carboxy-5-fluorophenylphthalazinone was obtained.

[0055] (2) Under a nitrogen atmosphere, 15 mmol of phenylphosphonyl dichloride and 180 mL of N,N-dimethylacetamide were added to a reaction flask, and after stirring, 33 mmol of 3-carboxy-5-fluorophenylphthalazinone and 40.2 mmol of potassium carbonate were added, and the mixture was reacted at 145° C. for 12 h. The mixture was filtered while hot, cooled for crystallization, washed with ethanol, and dried to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid.

[0056] (3) Under a nitrogen atmosphere, 100 g of 1,3-propylene glycol, 175 g of fluorine-containing phosphorus-nitrogen heterocyclic dicarboxylic acid, 70 g of phthalic anhydride, 40 g of maleic anhydride and 850 mL of o-xylene were added to a reaction flask, and the mixture was reacted at 160° C. for 8 h. The temperature was lowered to 110° C., 15 g of hydroquinone, 5 g of benzoyl peroxide and 60 g of styrene were added, and the mixture was stirred evenly at 135° C. to obtain a flame-retardant and heat-resistant unsaturated polyester.

[0057] (4) 35 g of glass fiber was evenly laid in the mold cavity of the manhole cover molding mold, and 50 g of flame retardant and heat-resistant unsaturated resin, 20 g of quartz sand, 10 g of light calcium carbonate and 3 g of active magnesium oxide were added and then heated at 95 ° C for 20 min, 2 g of antioxidant 1010, 5 g of polyvinyl acetate, 2 g of stearate and 0.02 g of cyclohexanone peroxide were added, the combined film was pressurized to 75 MPa, and hot-pressed at 155 ° C. The mold was opened and trimmed to obtain a wear-resistant fiberglass manhole cover containing polyester.

[0058] Comparative Example 1

[0059] (1) Under nitrogen atmosphere, 45 mmol of 6-bromo-2,3-phthalazinone, 1.62 mmol of tetrakis(triphenylphosphine)palladium and 360 mL of toluene were added to a reaction flask. After stirring, 50.4 mmol of 4-carboxyphenylboronic acid (structural formula: CAS No. 14047-29-1) and 75.6 mmol potassium phosphate, react at 100°C for 16 hours, extract with ethyl acetate and deionized water, concentrate the organic phase, and separate by column chromatography to obtain 4-carboxyphenylphthalazinone.

[0060] (2) Under nitrogen atmosphere, 40 mmol of phenylphosphonyl dichloride and 500 mL of N,N-dimethylacetamide were added to the reaction flask, and after stirring, 88 mmol of 4-carboxyphenylphthalazinone and 105 mmol of potassium carbonate were added, and the mixture was reacted at 140° C. for 8 h, filtered while hot, cooled and crystallized, washed with ethanol, and dried to obtain a phosphazene heterocyclic dicarboxylic acid (structural formula: ).

[0061] (3) Under a nitrogen atmosphere, 100 g of 1,3-propylene glycol, 35 g of phosphazene heterocyclic dicarboxylic acid, 65 g of phthalic anhydride, 40 g of maleic anhydride and 800 mL of o-xylene were added to a reaction flask, and the mixture was reacted at 150° C. for 5 h. The mixture was cooled to 110° C., 12 g of hydroquinone, 4 g of benzoyl peroxide and 70 g of styrene were added, and the mixture was stirred evenly at 125° C. to obtain a flame-retardant and heat-resistant unsaturated polyester.

[0062] (4) 30 g of glass fiber was evenly laid in the mold cavity of the manhole cover molding mold, and 30 g of flame retardant and heat-resistant unsaturated resin, 20 g of quartz sand, 8 g of light calcium carbonate and 4 g of active magnesium oxide were added and then heated at 90 ° C for 15 min, 2 g of antioxidant 1010, 5 g of polystyrene, 0.15 g of alkyl phosphatidic acid and 0.02 g of cyclohexanone peroxide were added, the combined film was pressurized to 70 MPa, and hot-pressed at 155 ° C. The mold was opened and trimmed to obtain a glass fiber reinforced plastic manhole cover.

[0063] Comparative Example 2

[0064] (1) Under nitrogen atmosphere, 100 g of 1,3-propylene glycol and 35 g of terephthalic acid (structural formula: CAS No. 100-21-0), 65g of phthalic anhydride, 40g of maleic anhydride and 800mL of o-xylene, react at 150°C for 5h, cool to 110°C, add 12g of hydroquinone, 4g of benzoyl peroxide and 70g of styrene, stir evenly at 125°C to obtain unsaturated polyester.

[0065] (2) 30 g of glass fiber was evenly laid in the mold cavity of the manhole cover molding mold, and 30 g of unsaturated resin, 20 g of quartz sand, 8 g of light calcium carbonate and 4 g of active magnesium oxide were added and then heated at 90 ° C for 15 min, 2 g of antioxidant 1010, 5 g of polystyrene, 0.15 g of alkyl phosphatidic acid and 0.02 g of cyclohexanone peroxide were added, the combined film was pressurized to 70 MPa, and hot-pressed at 155 ° C. The mold was opened and trimmed to obtain a glass fiber reinforced plastic manhole cover.

[0066] Limiting oxygen index test: refer to GB / T 2046-2008 standard test, the sample size is 130×6.5×3mm, and the test is carried out using a high temperature oxygen index instrument.

[0067] Vertical burning grade test: refer to GB / T 2408-2008 standard test, the sample size is 130×13×3mm, and the test is carried out using a vertical burning tester.

[0068] Table 1 Flame retardant performance test

[0069]

[0070] It can be seen from the test results in the above table that with the increase of the content of flame-retardant and heat-resistant unsaturated polyester, the limiting oxygen index in Example 5 reaches 34.7%, the vertical combustion grade is V-0, and there is no molten droplet and the flame is self-extinguishing. The flame retardant properties of FRP are gradually enhanced. This is because the flame-retardant and heat-resistant unsaturated polyester contains phosphorus-nitrogen synergistic flame retardant elements, in which phosphorus compounds are first decomposed into phosphoric acid when heated during combustion, and then lose water to form pyrophosphoric acid, and then generate metaphosphoric acid and polymetaphosphoric acid. These acid substances can promote the dehydration of unsaturated polyester into carbon, and effectively prevent the matrix from being oxidized and decomposed; nitrogen compounds mainly play a gas phase flame retardant role, and can produce a large amount of non-combustible gases such as nitrogen and ammonia during combustion, capture the free radicals generated by the thermal decomposition of the material, and play a role in diluting combustible gases such as oxygen; nitrogen and phosphorus synergistic flame retardant, so that the flame retardant properties of FRP materials are significantly improved.

[0071] Comparative Example 1 contains phosphorus and nitrogen flame retardant elements, and has good flame retardant properties; Comparative Example 2 does not contain phosphorus and nitrogen flame retardant elements, has no flame retardant properties, and is a flammable material.

[0072] Wear resistance test: Wear tests were carried out on an M200 wear testing machine under the conditions of a load of 100 kN, a rotation speed of 400 r / min, a friction pair of 45 steel and a wear time of 1 h, and then the wear amount of different samples was measured.

[0073] Table 2 Wear resistance test

[0074] Wear amount (mg) Example 1 0.016 Example 2 0.012 Example 3 0.007 Example 4 0.003 Example 5 0.002 Comparative Example 1 0.025 Comparative Example 2 0.028

[0075] It can be seen from the test results in the above table that with the increase of the content of flame retardant and heat-resistant unsaturated polyester, the wear resistance of the FRP material is enhanced, and the wear in Example 4 is only 0.003 mg. This is because on the one hand, the glass fiber itself has good wear resistance, which makes the material surface rough, increases the relative motion resistance of the friction interface, increases the wear resistance, and is wrapped and coated with the unsaturated resin in a mesh shape, which plays a supporting role in the process of friction and wear; on the other hand, the fluorine-containing groups in the flame retardant and heat-resistant unsaturated polyester can form fluorine-metal compounds on the sliding FRP surface, which has a good lubricating effect, helps to improve the wear resistance to prevent severe friction and wear, and the prepared flame retardant and heat-resistant unsaturated polyester molecular chain is spiral, which is beneficial to further reduce the friction between the molecular chains and increase the service life of the FRP manhole cover.

[0076] Bending strength test: The bending strength test was carried out in accordance with the standard GB / T 1449-2005. The experimental conditions were to place the test at 25°C and 100°C for 168 hours respectively.

[0077] Table 3 Heat resistance test

[0078]

[0079] From the test results in the above table, it can be seen that the heat resistance of the FRP manhole cover is significantly enhanced. The bending strength after being placed at 100°C for 168 hours is not much different from that at 25°C. This is because the twisted and non-coplanar diazonium phthalide biphenyl structure is introduced into the unsaturated polyester, and the molecular chain is highly rigid, which makes it easy for the unsaturated polyester to have molecular chain entanglement, play a role in resisting external forces, and improve the heat resistance of the material.

[0080] It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A wear-resistant fiberglass manhole cover containing polyester, characterized in that: The wear-resistant glass fiber reinforced plastic manhole cover comprises the following components in parts by weight: 30-50 parts of flame-retardant and heat-resistant unsaturated polyester, 15-25 parts of quartz sand, 25-40 parts of glass fiber, 5-10 parts of light calcium carbonate, 3-5 parts of active magnesium oxide, 1-3 parts of antioxidant, 2-6 parts of low-temperature shrinkage agent, 0.5-2 parts of internal release agent and 0.01-0.03 parts of cyclohexanone peroxide; The preparation method of the flame retardant and heat resistant unsaturated polyester is as follows: under a nitrogen atmosphere, 1,3-propylene glycol and a structural formula of Fluorine-containing phosphorus-nitrogen heterocyclic dicarboxylic acid, phthalic anhydride, maleic anhydride and o-xylene are reacted at 140-160°C for 3-8h, cooled to 100-115°C, hydroquinone, benzoyl peroxide and styrene are added, and stirred evenly at 120-135°C to obtain a flame-retardant and heat-resistant unsaturated polyester; The ratio of the 1,3-propylene glycol, the fluorine-containing phosphorus and nitrogen heterocyclic dicarboxylic acid, phthalic anhydride, maleic anhydride, hydroquinone, benzoyl peroxide and styrene is 100g: (35-175)g: (60-75)g: (35-50)g: (10-15)g: (3-6)g: (60-75)g; The preparation method of the fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid is: Step (1), under a nitrogen atmosphere, add 6-bromo-2,3-phthalazinone, tetrakis(triphenylphosphine)palladium and toluene to a reaction flask, stir evenly, add 3-carboxy-5-fluorophenylboric acid and potassium phosphate, stir to react, after the reaction is completed, extract with ethyl acetate and deionized water, concentrate the organic phase, and separate by column chromatography to obtain 3-carboxy-5-fluorophenylphthalazinone; Step (2), under nitrogen atmosphere, add phenylphosphonyl dichloride and N,N-dimethylacetamide to a reaction flask, stir evenly, add 3-carboxy-5-fluorophenylphthalazinone and potassium carbonate, react at 130-150° C. for 5-12 h, filter while hot, cool to crystallize, wash with ethanol, and dry to obtain a fluorine-containing phosphorus nitrogen heterocyclic dicarboxylic acid.

2. The wear-resistant fiberglass manhole cover containing polyester according to claim 1, characterized in that: The low-temperature shrinkage agent is any one of polystyrene, polyethylene or polyvinyl acetate.

3. The wear-resistant fiberglass manhole cover containing polyester according to claim 1, characterized in that: The internal mold release agent is any one of alkyl phosphatidic acid, stearate or lecithin.

4. The wear-resistant fiberglass manhole cover containing polyester according to claim 1, characterized in that: In the step (1), the ratio of 6-bromo-2,3-phthalazinone, tetrakis(triphenylphosphine)palladium, 3-carboxy-5-fluorophenylboric acid and potassium phosphate is 1 mol: (0.02-0.05) mol: (1.05-1.2) mol: (1.5-2) mol.

5. The wear-resistant fiberglass manhole cover containing polyester according to claim 1, characterized in that: In the step (1), the reaction temperature is 90-105° C. and the reaction time is 12-24 h.

6. The wear-resistant fiberglass manhole cover containing polyester according to claim 1, characterized in that: In the step (2), the ratio of phenylphosphonyl dichloride, 3-carboxy-5-fluorophenylphthalazinone and potassium carbonate is 1 mol: (2.1-2.3) mol: (2.4-2.8) mol.

7. A method for preparing the polyester-containing wear-resistant glass fiber reinforced plastic manhole cover according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: evenly laying glass fiber in the mold cavity of a manhole cover forming mold, adding flame-retardant and heat-resistant unsaturated resin, quartz sand, light calcium carbonate and active magnesium oxide which are evenly mixed, and then heating at 80-100° C. for 10-20 minutes, adding an antioxidant, a low-temperature shrink agent, an internal mold release agent and cyclohexanone peroxide, closing the mold and pressurizing it, hot-pressing it at 140-160° C., opening the mold and trimming the edges, and obtaining a wear-resistant fiberglass manhole cover containing polyester.

8. The method for preparing the polyester-containing wear-resistant glass fiber reinforced plastic manhole cover according to claim 7, characterized in that: The pressure of the film closing pressurization is 60-80MPa.

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