Phenolic epoxy resin as well as preparation method and application thereof

Abstract

The invention relates to novolac epoxy resin as well as a preparation method and application thereof, the preparation method of the novolac epoxy resin comprises the following steps: carrying out phenolic aldehyde condensation reaction on a bisphenol A byproduct and aldehyde under the action of an acid catalyst to obtain phenolic resin; and reacting the obtained phenolic resin with an epoxy compound under the action of a phase transfer catalyst and alkali to obtain the novolac epoxy resin. The phenolic epoxy resin is prepared by taking the bisphenol A byproduct as the raw material and is used for preparing the epoxy fracturing proppant, so that the comprehensive performance of the fracturing proppant can be greatly improved, high-added-value resource utilization of hazardous wastes is realized, and meanwhile, the production cost of the fracturing proppant is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of bisphenol A byproducts, and in particular to a phenolic epoxy resin and a preparation method and application thereof. Background Art

[0002] Bisphenol A (BPA), whose full name is 2,2-bis(4-hydroxyphenyl)propane, is an important organic chemical raw material, mainly used in the production of epoxy resins, polycarbonates, polysulfone resins, unsaturated polyester resins and other polymer materials. At present, bisphenol A is mainly prepared by the condensation reaction of phenol and acetone under the action of an acidic catalyst. In the process, polyphenol impurities such as bisphenol A isomers, cyclodimers, hydroxy trimers, triphenols, and chromanes are generated. After the target product is separated, the above impurities are discharged from the system as by-products with the remaining phenol and bisphenol A. The production of one ton of BPA emits about 25-30kg of by-products. At present, most bisphenol A manufacturers adopt direct incineration or cracking for incineration disposal. The incineration process is mature and the treatment is thorough, but the investment in incineration equipment is large, the flue gas generated needs secondary treatment, and the economic efficiency is poor, which leads to increased production costs and waste of resources.

[0003] CN114874798A discloses a bisphenol A tar resource processing device and method, which uses bisphenol A tar as raw material, and efficiently and low-consumption completes the recovery of bisphenol A from bisphenol A tar, a byproduct of the condensation of phenol and acetone to produce bisphenol A, through the steps of pyrolysis, deweighting, coarse separation and refining in a step-by-step and orderly manner, and also obtains component products such as phenol, isopropenylphenol and asphalt. However, this method involves high-temperature cracking reaction, harsh process conditions, complex product composition, and greater separation difficulty, resulting in high equipment investment and energy consumption.

[0004] CN112409573A discloses a by-product polyphenol epoxy resin and its manufacturing method and application. The BPA mother liquor obtained after solid-liquid separation in the industrial production of bisphenol A is distilled to remove small molecular phenol compounds such as phenol under high temperature and high vacuum conditions to obtain a by-product polyphenol. The by-product polyphenol is dissolved in epichlorohydrin to prepare a polyphenol epoxy resin, which can be used in the fields of casting materials, electronic potting materials, fiber-reinforced composite materials, etc. However, the resource-based epoxy resin has poor chromaticity and small market demand, making it difficult to apply it on a large scale in industry.

[0005] In summary, the current treatment methods for bisphenol A byproducts have the disadvantages of harsh process conditions, high equipment investment costs, poor environmental protection and low added value. Therefore, it is urgent to develop a bisphenol A byproduct resource recovery method with mild process conditions, convenient operation, strong environmental protection and high added value.

[0006] Petroleum fracturing proppant is a closed material widely used in oil and gas production, mainly used for downhole support in oil fields to increase oil and gas production. The main types of proppant are quartz sand and artificial ceramsite, but their compressive strength is relatively low, and they are easy to break during use. After breaking, particles migrate and block the pore throat, which will cause the fracture conductivity to decrease. In order to improve the anti-breakage ability of the proppant, a curable organic proppant is wrapped on the outer layer of quartz sand or ceramic material, mostly phenolic resin, and a small amount of epoxy resin is used, which can partially reduce the density of the fracturing proppant and wrap the broken sand particles at the same time to prevent the broken sand particles from migrating and causing sand problems.

[0007] CN117551445A discloses a petroleum fracturing proppant based on solid waste and its preparation method. After resin modification and curing, the strength is significantly improved, the proppant toughness is better, and the polymer coating will first consume a lot of energy before the ceramsite is brittlely broken, preventing the crack from expanding and causing the proppant to break. At the same time, the broken particles can be firmly coated inside the coating, reducing the damage of the particles to the fracture channel. However, the preparation cost of the modified resin is high, and large-scale application has certain limitations. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a phenolic epoxy resin and a preparation method and application thereof, and to synthesize the phenolic epoxy resin using bisphenol A by-product as a raw material for a low-density fracturing proppant, thereby realizing the high added value utilization of bisphenol A by-products.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a phenolic epoxy resin, the preparation method comprising the following steps:

[0011] The bisphenol A byproduct and aldehyde are subjected to a phenolic condensation reaction under the action of an acid catalyst to obtain a phenolic resin; the obtained phenolic resin is reacted with an epoxy compound under the action of a phase transfer catalyst and a base to obtain the phenolic epoxy resin.

[0012] The preparation method of the phenolic epoxy resin provided by the present invention uses bisphenol A byproduct as a raw material, reacts with aldehyde to obtain phenolic resin, and then reacts the phenolic resin with an epoxy compound to obtain phenolic epoxy resin. Compared with bisphenol A type epoxy resin, the phenolic epoxy resin prepared from the bisphenol A byproduct has a phenolic structure, has a high degree of crosslinking after curing, excellent thermal stability and mechanical strength, and a high glass transition temperature. At the same time, the steric hindrance effect generated by the functional groups on the phenol molecules can further improve the heat resistance. The phenolic epoxy resin is used for preparing an epoxy fracturing proppant, which can greatly improve the comprehensive performance of the fracturing proppant and reduce its production cost.

[0013] Preferably, the bisphenol A by-product contains 3-10 wt % phenol, 5-50 wt % bisphenol A, and the remainder is composed of at least one of the structures shown in Formula I to Formula IX.

[0014]

[0015] The phenol content in the bisphenol A by-product is 3-10wt%, for example, 3wt%, 5wt%, 7wt%, 8wt% or 10wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] The bisphenol A content in the bisphenol A by-product is 5-50wt%, for example, 5wt%, 10wt%, 20wt%, 30wt%, 41wt% or 50wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the aldehyde comprises any one of formaldehyde aqueous solution, paraformaldehyde, acetaldehyde or propionaldehyde, or a combination of at least two of them. Typical but non-limiting combinations include a combination of formaldehyde aqueous solution and paraformaldehyde, a combination of paraformaldehyde, acetaldehyde and propionaldehyde, or a combination of formaldehyde aqueous solution, paraformaldehyde, acetaldehyde and propionaldehyde.

[0018] Preferably, the mass ratio of the aldehyde to the bisphenol A by-product is (0.01-0.1):1, for example, it can be 0.01:1, 0.03:1, 0.05:1, 0.08:1 or 0.1:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the acid catalyst comprises any one of oxalic acid, p-toluenesulfonic acid or hydrochloric acid or a combination of at least two thereof, and typical but non-limiting combinations include a combination of oxalic acid and p-toluenesulfonic acid, a combination of p-toluenesulfonic acid and hydrochloric acid, or a combination of oxalic acid, p-toluenesulfonic acid and hydrochloric acid.

[0020] Preferably, the mass ratio of the acid catalyst to the bisphenol A by-product is (0.004-0.05):1, for example, it can be 0.004:1, 0.005:1, 0.008:1, 0.01:1, 0.03:1 or 0.05:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, an organic solvent is added to the phenol-formaldehyde condensation reaction.

[0022] Preferably, the organic solvent is toluene.

[0023] Preferably, the specific steps of the phenolic condensation reaction include: heating to 73-77° C., reacting for 1.8-2.2 hours; continuing to heat to 83-87° C., reacting for 0.8-1.2 hours, and then removing the organic solvent under negative pressure.

[0024] The end point of the heating temperature is 73-77°C, for example, it can be 73°C, 74°C, 75°C, 76°C or 77°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] The reaction time is 1.8-2.2 h, for example, 1.8 h, 1.9 h, 2 h, 2.1 h or 2.2 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] The end point of the temperature of the continued heating is 83-87°C, for example, it can be 83°C, 84°C, 85°C, 86°C or 87°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] The reaction time is 0.8-1.2 h, for example, 0.8 h, 0.9 h, 1 h, 1.1 h or 1.2 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the phenolic resin has a macromolecular structure, which is obtained by a phenolic condensation reaction of at least one of the structures shown in Formula I to Formula IX, and has a degree of polymerization of 1, 2 or 3.

[0029]

[0030] The macromolecular structure can be a phenolic condensation of formula III (a), a phenolic condensation of formula III and formula II (b), a phenolic condensation of formula I, formula III and formula VI (c), or a phenolic condensation of formula VIII and formula IX (d), but is not limited to the listed structures, and other structures not listed within the scope are also applicable.

[0031]

[0032] Preferably, the softening point of the phenolic resin is 75-110°C, for example, 75°C, 85°C, 95°C, 99°C, 100°C or 110°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the mass ratio of the phenolic resin to the epoxy compound is 1:(2-10), for example, it can be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the epoxy compound is epichlorohydrin.

[0035] Preferably, the phase transfer catalyst comprises any one of benzyltriethylammonium chloride, tetrabutylammonium bromide, benzyltrimethylammonium chloride or ethyltriphenylammonium bromide or a combination of at least two thereof, and typical but non-limiting combinations include a combination of benzyltriethylammonium chloride and tetrabutylammonium bromide, a combination of tetrabutylammonium bromide, benzyltrimethylammonium chloride and ethyltriphenylammonium bromide, or a combination of benzyltriethylammonium chloride, tetrabutylammonium bromide, benzyltrimethylammonium chloride and ethyltriphenylammonium bromide.

[0036] Preferably, the mass ratio of the phenolic resin to the phase transfer catalyst is 1:(0.005-0.02), for example, it can be 1:0.005, 1:0.006, 1:0.007, 1:0.008, 1:0.009, 1:0.01, 1:0.015 or 1:0.02, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the alkali comprises a sodium hydroxide solution with a mass concentration of 30-50%, for example, 30%, 35%, 40%, 48% or 50%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the mass ratio of the alkali to the phenolic resin is 1:(1.8-2.2), for example, it can be 1:1.8, 1:1.9, 1:2, 1:2.1 or 1:2.2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the specific steps of the reaction include: etherification reaction of phenolic resin and epoxy compound under the action of phase transfer catalyst, then adding base to continue the reaction; removing epoxy compound after negative pressure water, adding toluene and deionized water for washing, and then removing toluene.

[0040] Preferably, the temperature of the etherification reaction is 108-112° C., and the time is 2.8-3.2 h.

[0041] The temperature of the etherification reaction is 108-112°C, for example, 108°C, 109°C, 110°C, 111°C or 112°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] The etherification reaction time is 2.8-3.2 h, for example, 2.8 h, 2.9 h, 3 h, 3.1 h or 3.2 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] Preferably, the pressure when adding the alkali is 11-16 kPa, for example, 11 kPa, 12 kPa, 13 kPa, 15 kPa or 16 kPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the temperature of the negative pressure water is 54-58°C, for example, 54°C, 55°C, 56°C, 57°C or 58°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the epoxy equivalent of the novolac epoxy resin is 220-260 g / mol, for example, 220 g / mol, 221 g / mol, 235 g / mol, 240 g / mol or 260 g / mol, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In a second aspect, the present invention provides a phenolic epoxy resin, which is prepared by the preparation method of the phenolic epoxy resin described in the first aspect.

[0047] The phenolic epoxy resin provided by the present invention has mild preparation process conditions, small equipment investment, and strong environmental protection. Compared with bisphenol A epoxy resin, various properties are improved after curing. It is used in the preparation of epoxy fracturing proppants to greatly improve the performance of fracturing proppants.

[0048] In a third aspect, the present invention provides a use of the phenolic epoxy resin as described in the second aspect, wherein the phenolic epoxy resin is used to prepare a fracturing proppant, and the preparation method comprises the following steps:

[0049] The phenolic epoxy resin, pretreated raw sand, curing agent, accelerator and dispersant are uniformly mixed, the obtained mixture is subjected to curing reaction with silicone oil, the obtained reaction liquid is subjected to solid-liquid separation, and the obtained solid phase is washed to obtain the fracturing proppant.

[0050] In the present invention, phenolic epoxy resin is used to prepare fracturing proppants, which can meet various high performance requirements of fracturing proppants. The fracturing proppants have a glass transition temperature of 173-208°C and a density of 1.14-1.22 g / cm 3 , realizing the high value-added resource utilization of hazardous waste, increasing the added value of products and reducing the production cost of fracturing proppants.

[0051] Preferably, the pretreated raw sand is obtained by sequentially subjecting raw sand to heat treatment and silane coupling agent soaking treatment.

[0052] Preferably, the raw sand comprises quartz sand and / or ceramsite.

[0053] Preferably, the heat treatment is carried out at a temperature of 135-145°C and a time of 2.8-3.2 hours.

[0054] The temperature of the heat treatment is 135-145°C, for example, 135°C, 138°C, 140°C, 142°C or 145°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0055] The heat treatment time is 2.8-3.2 h, for example, 2.8 h, 2.9 h, 3 h, 3.1 h or 3.2 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0056] Preferably, the material is cooled to room temperature after the heat treatment and before the silane coupling agent immersion treatment.

[0057] Preferably, the silane coupling agent includes any one of vinyltrimethoxysilane, vinyltriethoxysilane, γ-(2,3-epoxypropoxy)-propyltrimethoxysilane or γ-(2,3-epoxypropoxy)-propyltriethoxysilane, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of vinyltrimethoxysilane and vinyltriethoxysilane, a combination of vinyltriethoxysilane, γ-(2,3-epoxypropoxy)-propyltrimethoxysilane and γ-(2,3-epoxypropoxy)-propyltriethoxysilane, or a combination of vinyltrimethoxysilane, vinyltriethoxysilane, γ-(2,3-epoxypropoxy)-propyltrimethoxysilane and γ-(2,3-epoxypropoxy)-propyltriethoxysilane.

[0058] Preferably, the soaking treatment time is 38-42 minutes, for example, 38 minutes, 39 minutes, 40 minutes, 41 minutes or 42 minutes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] Preferably, the curing agent includes any one of urotropine, triethylenetetramine, hexamethyltetramine or ethylenediamine, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of urotropine and triethylenetetramine, a combination of triethylenetetramine, hexamethyltetramine and ethylenediamine, or a combination of urotropine, triethylenetetramine, hexamethyltetramine and ethylenediamine.

[0060] Preferably, the accelerator comprises any one of phenyldimethylurea, DMP-30, N,N-dimethylbenzylamine, triethanolamine, 2-methylimidazole or 2-ethyl-4-methylimidazole, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of phenyldimethylurea and DMP-30, a combination of N,N-dimethylbenzylamine, triethanolamine, 2-methylimidazole and 2-ethyl-4-methylimidazole, or a combination of phenyldimethylurea, DMP-30, N,N-dimethylbenzylamine, triethanolamine, 2-methylimidazole and 2-ethyl-4-methylimidazole.

[0061] Preferably, the dispersant includes any one of calcium stearate, zinc stearate or stearic acid amide or a combination of at least two thereof, and typical but non-limiting combinations include a combination of calcium stearate and zinc stearate, a combination of zinc stearate and stearic acid amide, or a combination of calcium stearate, zinc stearate and stearic acid amide.

[0062] Preferably, the mass ratio of the raw sand, phenolic epoxy resin, silane coupling agent, curing agent, accelerator and dispersant is 1:(0.1-3):(0.01-0.5):(0.1-2):(0.1-1):(0.1-1), for example, it can be 1:0.2:0.01:0.1:0.1:0.1, 1:0.1:0.1:1:0.5:0.5 or 1:3:0.5:2:1:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] Preferably, the molecular weight of the silicone oil is 1000-20000, for example, 1000, 5000, 10000, 15000 or 20000, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] Preferably, the curing reaction temperature is 110-160° C. and the time is 1-10 h.

[0065] The temperature of the curing reaction is 110-160°C, for example, 110°C, 120°C, 130°C, 140°C or 160°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0066] The curing reaction time is 1-10 hours, for example, 1 hour, 2 hours, 5 hours, 8 hours or 10 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0067] Preferably, the washing reagent comprises toluene.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] The preparation method of the phenolic epoxy resin provided by the present invention uses bisphenol A byproduct as a raw material, reacts with aldehyde to obtain phenolic resin, and then reacts the phenolic resin with an epoxy compound to obtain phenolic epoxy resin. The preparation process conditions are mild, the equipment investment is small, and the environmental protection is strong. Compared with the bisphenol A type epoxy resin, the phenolic epoxy resin prepared from the bisphenol A byproduct has a phenolic structure, has a high crosslinking degree after curing, excellent thermal stability and mechanical strength, and a high glass transition temperature. At the same time, the steric hindrance effect generated by the functional groups on the phenol molecules can further improve the heat resistance. The phenolic epoxy resin is used for preparing an epoxy fracturing proppant, and can greatly improve the comprehensive performance of the fracturing proppant. The fracturing proppant has a glass transition temperature of 173-208°C and a density of 1.14-1.22g / cm 3 , while reducing the production cost of fracturing proppants. DETAILED DESCRIPTION

[0070] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0071] The bisphenol A by-products in the following examples all come from Jiangsu Ruiheng New Material Technology Co., Ltd.

[0072] In the following examples, the glass transition temperature of the fracturing proppant was tested by differential scanning calorimetry with reference to GB / T19466.2-2004; the density was tested with reference to SY / T 5108-2014.

[0073] Example 1

[0074] This embodiment provides a phenolic epoxy resin, and the preparation method of the phenolic epoxy resin comprises the following steps:

[0075] The bisphenol A byproduct, paraformaldehyde and toluene are subjected to a phenolic condensation reaction under the action of oxalic acid. In the phenolic condensation reaction, the temperature is raised to 75°C and the reaction is carried out for 2 hours; the temperature is further raised to 85°C and the reaction is carried out for 1 hour, and then the toluene is removed under negative pressure to obtain a phenolic resin; the phenol content in the bisphenol A byproduct is 7wt%, the bisphenol A content is 41wt%, and the remainder is composed of the structures shown in Formula I to Formula IX: The mass ratio of the paraformaldehyde to the bisphenol A byproduct is 0.03:1; the mass ratio of the oxalic acid to the bisphenol A byproduct is 0.005:1; the softening point of the phenolic resin is 85°C;

[0076] The obtained phenolic resin and epichlorohydrin are subjected to etherification reaction at 110°C for 3 hours under the action of benzyltriethylammonium chloride, and then a sodium hydroxide solution with a mass concentration of 48% is added at 13 kPa to continue the reaction; epichlorohydrin is removed after negative pressure water is added at 55°C, toluene and deionized water are added for washing, and then toluene is removed to obtain a phenolic epoxy resin with an epoxy equivalent of 221 g / mol; the mass ratio of the phenolic resin to epichlorohydrin is 1:6; the mass ratio of the phenolic resin to benzyltriethylammonium chloride is 1:0.015; and the mass ratio of the sodium hydroxide solution to the phenolic resin is 1:2.

[0077] The phenolic epoxy resin is used to prepare a fracturing proppant, and the preparation method comprises the following steps:

[0078] The quartz sand is heat treated at 140° C. for 3 hours and then cooled to room temperature, and then soaked in vinyl trimethoxysilane for 40 minutes to obtain pretreated quartz sand; the pretreated quartz sand, phenolic epoxy resin, triethylenetetramine, DMP-30 and calcium stearate are uniformly mixed, and the mass ratio of the pretreated quartz sand, phenolic epoxy resin, vinyl trimethoxysilane, triethylenetetramine, DMP-30 and calcium stearate is 1:0.2:0.01:0.1:0.1:0.1; the obtained mixture is cured with silicone oil with a molecular weight of 5000 at 140° C. for 2 hours, the obtained reaction solution is filtered, and the obtained solid phase is washed with toluene to obtain the fracturing proppant.

[0079] Example 2

[0080] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Embodiment 1 is that, except that the mass ratio of the paraformaldehyde to the bisphenol A byproduct is adjusted to 0.05:1, the rest is the same as that of Embodiment 1.

[0081] Example 3

[0082] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Embodiment 1 is that, except that the mass ratio of the paraformaldehyde to the bisphenol A byproduct is adjusted to 0.08:1, the rest is the same as that of Embodiment 1.

[0083] Comparative Example 1

[0084] This comparative example provides an epoxy resin. The difference between the preparation method of the epoxy resin and that of Example 1 is that no paraformaldehyde is added, and the bisphenol A byproduct does not undergo a phenolic condensation reaction, but directly reacts with epichlorohydrin in the presence of benzyltriethylammonium chloride and sodium hydroxide solution to finally obtain the epoxy resin. The rest is the same as that of Example 1.

[0085] The properties of the fracturing proppants prepared in Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0086] Table 1

[0087] Softening point / ℃ Epoxy equivalent / g / mol Glass transition temperature / ℃ <![CDATA[Density / g / cm 3 > Example 1 85 221 185 1.15 Example 2 94 242 189 1.20 Example 3 110 255 196 1.22 Comparative Example 1 <30 200 156 1.12

[0088] As can be seen from Table 1, increasing the amount of aldehyde can effectively increase the softening point of phenolic resin and increase the epoxy equivalent of phenolic epoxy resin. The product is used in fracturing proppants, which can effectively increase the glass transition temperature and has little effect on the density of pressure proppants. If the bisphenol A byproduct is not synthesized through phenolic resin and the corresponding epoxy resin is directly prepared, the softening point of the product is significantly reduced, and the glass transition temperature of the prepared fracturing proppants is significantly reduced.

[0089] Example 4

[0090] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Example 1 is that, except that the mass ratio of the phenolic resin to benzyltriethylammonium chloride is adjusted to 1:0.005, the rest is the same as that of Example 1.

[0091] Example 5

[0092] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Example 1 is that, except that the mass ratio of the phenolic resin to benzyltriethylammonium chloride is adjusted to 1:0.007, the rest is the same as that of Example 1.

[0093] Example 6

[0094] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Example 1 is that, except that the mass ratio of the phenolic resin to benzyltriethylammonium chloride is adjusted to 1:0.01, the rest is the same as that of Example 1.

[0095] Example 7

[0096] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Example 1 is that, except that the mass ratio of the phenolic resin to benzyltriethylammonium chloride is adjusted to 1:0.02, the rest is the same as that of Example 1.

[0097] Comparative Example 2

[0098] This comparative example provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Example 1 is that, except that the mass ratio of the phenolic resin to benzyltriethylammonium chloride is adjusted to 1:0.03, the rest is the same as that of Example 1.

[0099] Comparative Example 3

[0100] This comparative example provides a phenolic resin, which is different from Example 1 in that no benzyltriethylammonium chloride is added, and no epoxy resin synthesis reaction is performed. The phenolic resin is directly used to prepare a fracturing proppant, and the rest is the same as Example 1.

[0101] The properties of the fracturing proppants prepared in Examples 1, 4-7 and Comparative Examples 2 and 3 are shown in Table 2.

[0102] Table 2

[0103] Softening point / ℃ Epoxy equivalent / g / mol Glass transition temperature / ℃ <![CDATA[Density / g / cm 3 > Example 1 85 221 185 1.15 Example 4 85 242 173 1.15 Example 5 88 236 176 1.15 Example 6 86 228 182 1.16 Example 7 85 210 191 1.16 Comparative Example 2 85 209 190 1.15 Comparative Example 3 85 - 95 1.12

[0104] As can be seen from Table 2, when the mass ratio of phenolic resin to phase transfer catalyst increases to 1:0.02, the conversion rate of etherification reaction increases, resulting in a decrease in the epoxide equivalent of the product, and the application of fracturing proppants increases the glass transition temperature; when the mass ratio of phenolic resin to phase transfer catalyst continues to increase to 1:0.03, the epoxide equivalent of the product and the glass transition temperature of the fracturing proppants do not change significantly. According to Comparative Example 3, it can be seen that when the phenolic resin synthesized from the byproduct of bisphenol A is directly used for fracturing proppants, the glass transition temperature of the fracturing proppants is significantly reduced.

[0105] Example 8

[0106] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Example 1 is that, except that the phenol content in the bisphenol A by-product is adjusted to 3wt% and the bisphenol A content is adjusted to 44wt%, the rest is the same as that of Example 1.

[0107] Example 9

[0108] This embodiment provides a phenolic epoxy resin. The difference between the preparation method of the phenolic epoxy resin and that of Example 1 is that, except that the phenol content in the bisphenol A by-product is adjusted to 10wt% and the bisphenol A content is adjusted to 38wt%, the rest is the same as that of Example 1.

[0109] Example 10

[0110] This embodiment provides a novolac epoxy resin. The difference between the preparation method of the novolac epoxy resin and that of Embodiment 1 is that the bisphenol A byproduct does not contain phenol and bisphenol A, and the rest is the same as that of Embodiment 1.

[0111] Comparative Example 4

[0112] This comparative example provides a bisphenol A epoxy resin, which is different from Example 1 in that bisphenol A is used as a raw material, and the obtained bisphenol A epoxy resin is used to prepare a fracturing proppant without undergoing a phenolic resin synthesis reaction. The rest is the same as Example 1.

[0113] The properties of the fracturing proppants prepared in Examples 1, 8-10 and Comparative Example 4 are shown in Table 3.

[0114] Table 3

[0115] Softening point / ℃ Epoxy equivalent / g / mol Glass transition temperature / ℃ <![CDATA[Density / g / cm 3 > Example 1 85 221 185 1.15 Example 8 82 225 187 1.15 Example 9 86 220 182 1.14 Example 10 101.5 243 208 1.22 Comparative Example 4 - 180 150 1.12

[0116] As can be seen from Table 3, the phenol content in the bisphenol A byproduct is 3-10wt%, and the bisphenol A content is 38-44wt%, which has little effect on the softening point of the phenolic resin, the epoxy equivalent of the product, the glass transition temperature of the fracturing proppant, and the density; when phenol and bisphenol A are removed from the bisphenol A byproduct, the softening point of the synthesized phenolic resin is significantly increased, the epoxy equivalent of the product is significantly increased, and the glass transition temperature of the fracturing proppant is increased. According to Comparative Example 4, it can be seen that when bisphenol A is directly used to synthesize bisphenol A type epoxy resin, the epoxy equivalent of the product is reduced, and the glass transition temperature used for the fracturing proppant is significantly reduced.

[0117] In summary, the preparation method of the phenolic epoxy resin provided by the present invention uses bisphenol A byproduct as a raw material, reacts with aldehyde to obtain a phenolic resin, and then reacts the phenolic resin with an epoxy compound to obtain a phenolic epoxy resin. The preparation process conditions are mild, the equipment investment is small, and the environmental protection is strong. Compared with the bisphenol A type epoxy resin, the phenolic epoxy resin prepared from the bisphenol A byproduct has a phenolic structure, a high degree of crosslinking after curing, excellent thermal stability and mechanical strength, and a high glass transition temperature. At the same time, the steric hindrance effect generated by the functional groups on the phenol molecules can further improve the heat resistance. The epoxy fracturing proppant can be used to prepare the epoxy fracturing proppant, which can greatly improve the comprehensive performance of the fracturing proppant. The fracturing proppant has a glass transition temperature of 173-208°C and a density of 1.14-1.22g / cm 3 , while reducing the production cost of fracturing proppants.

[0118] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a phenolic epoxy resin, characterized in that: The preparation method comprises the following steps: The bisphenol A byproduct and aldehyde are subjected to a phenolic condensation reaction under the action of an acid catalyst to obtain a phenolic resin; the obtained phenolic resin is reacted with an epoxy compound under the action of a phase transfer catalyst and a base to obtain the phenolic epoxy resin.

2. The preparation method according to claim 1, characterized in that: The bisphenol A by-product has a phenol content of 3-10 wt %, and a bisphenol A content of 5-50 wt %; Preferably, the aldehyde comprises any one or a combination of at least two of aqueous formaldehyde solution, paraformaldehyde, acetaldehyde or propionaldehyde; Preferably, the mass ratio of the aldehyde to the bisphenol A byproduct is (0.01-0.1):1; Preferably, the acid catalyst comprises any one of oxalic acid, p-toluenesulfonic acid or hydrochloric acid or a combination of at least two thereof; Preferably, the mass ratio of the acid catalyst to the bisphenol A by-product is (0.004-0.05):

1.

3. The preparation method according to claim 1 or 2, characterized in that: An organic solvent is added to the phenolic condensation reaction; Preferably, the organic solvent is toluene; Preferably, the specific steps of the phenolic condensation reaction include: heating to 73-77° C., reacting for 1.8-2.2 hours; continuing to heat to 83-87° C., reacting for 0.8-1.2 hours, and then removing the organic solvent under negative pressure.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The phenolic resin has a macromolecular structure, which is obtained by a phenolic condensation reaction of at least one of the structures shown in Formula I to Formula IX, and has a degree of polymerization of 1, 2 or 3; Preferably, the softening point of the phenolic resin is 75-110°C; Preferably, the mass ratio of the phenolic resin to the epoxy compound is 1:(2-10); Preferably, the epoxy compound is epichlorohydrin; Preferably, the phase transfer catalyst comprises any one or a combination of at least two of benzyltriethylammonium chloride, tetrabutylammonium bromide, benzyltrimethylammonium chloride or ethyltriphenylammonium bromide; Preferably, the mass ratio of the phenolic resin to the phase transfer catalyst is 1:(0.005-0.02); Preferably, the alkali comprises a sodium hydroxide solution having a mass concentration of 30-50%; Preferably, the mass ratio of the alkali to the phenolic resin is 1:(1.8-2.2).

5. The preparation method according to any one of claims 1 to 4, characterized in that: The specific steps of the reaction include: etherification reaction of phenolic resin and epoxy compound under the action of phase transfer catalyst, then adding alkali to continue the reaction; removing epoxy compound after negative pressure water, adding toluene and deionized water for washing, and then removing toluene; Preferably, the temperature of the etherification reaction is 108-112°C and the time is 2.8-3.2h; Preferably, the pressure when adding the alkali is 11-16 kPa; Preferably, the temperature of the negative pressure water is 54-58°C; Preferably, the epoxy equivalent of the novolac epoxy resin is 220-260 g / mol.

6. A phenolic epoxy resin, characterized in that: The phenolic epoxy resin is prepared by the preparation method of the phenolic epoxy resin according to any one of claims 1 to 5.

7. An application of the phenolic epoxy resin as claimed in claim 6, characterized in that: The phenolic epoxy resin is used to prepare a fracturing proppant, and the preparation method comprises the following steps: The phenolic epoxy resin, pretreated raw sand, curing agent, accelerator and dispersant are uniformly mixed, the obtained mixture is subjected to curing reaction with silicone oil, the obtained reaction liquid is subjected to solid-liquid separation, and the obtained solid phase is washed to obtain the fracturing proppant.

8. The use according to claim 7, characterized in that: The pretreated raw sand is obtained by sequentially subjecting raw sand to heat treatment and silane coupling agent soaking treatment; Preferably, the raw sand comprises quartz sand and / or ceramsite; Preferably, the heat treatment temperature is 135-145°C and the time is 2.8-3.2h; Preferably, cooling to room temperature after the heat treatment and before the silane coupling agent soaking treatment; Preferably, the silane coupling agent includes any one of vinyltrimethoxysilane, vinyltriethoxysilane, γ-(2,3-epoxypropoxy)-propyltrimethoxysilane or γ-(2,3-epoxypropoxy)-propyltriethoxysilane, or a combination of at least two thereof; Preferably, the soaking treatment time is 38-42 minutes.

9. The use according to claim 8, characterized in that: The curing agent includes any one of hexamethylenetetramine, triethylenetetramine, hexamethyltetramine or ethylenediamine, or a combination of at least two thereof; Preferably, the accelerator comprises any one or a combination of at least two of phenyldimethylurea, DMP-30, N,N-dimethylbenzylamine, triethanolamine, 2-methylimidazole or 2-ethyl-4-methylimidazole; Preferably, the dispersant includes any one of calcium stearate, zinc stearate or stearic acid amide or a combination of at least two thereof; Preferably, the mass ratio of the raw sand, phenolic epoxy resin, silane coupling agent, curing agent, accelerator and dispersant is 1:(0.1-3):(0.01-0.5):(0.1-2):(0.1-1):(0.1-1).

10. The use according to any one of claims 7 to 9, characterized in that: The molecular weight of the silicone oil is 1000-20000; Preferably, the curing reaction temperature is 110-160°C and the time is 1-10h; Preferably, the washing reagent comprises toluene.

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