阅读说明：本技术 一种bpa-ga酚醛环氧树脂及其制备方法 (BPA-GA novolac epoxy resin and preparation method thereof ) 是由 郭睿 闫育蒙 马丽娟 徐康 张晓飞 于 2020-06-22 设计创作，主要内容包括：本发明提供一种BPA-GA酚醛环氧树脂及其制备方法,所述方法包括如下步骤：步骤1,先将BPA-GA酚醛树脂、环氧氯丙烷和四丁基溴化铵混合均匀,得到混合体系A,之后将混合体系A在95～115℃下进行反应,反应完成后所得的反应液降温至58～62℃,得到混合体系B；步骤2,先在混合体系B中加入NaOH溶液,之后在65～75℃后反应0.8～1.2h,得到BPA-GA酚醛环氧树脂粗产物；步骤3,将BPA-GA酚醛环氧树脂粗产物中的杂质去除并干燥,得到BPA-GA酚醛环氧树脂,它不但具有双酚A甲醛酚醛环氧树脂的耐热性能,而且提高了酚醛环氧树脂的韧性,进一步扩大了双酚A的应用范围。(The invention provides BPA-GA novolac epoxy resin and a preparation method thereof, wherein the method comprises the following steps: step 1, uniformly mixing BPA-GA phenolic resin, epoxy chloropropane and tetrabutylammonium bromide to obtain a mixed system A, then reacting the mixed system A at 95-115 ℃, and cooling the obtained reaction liquid to 58-62 ℃ after the reaction is finished to obtain a mixed system B; step 2, firstly adding a NaOH solution into the mixed system B, and then reacting for 0.8-1.2 h at 65-75 ℃ to obtain a BPA-GA novolac epoxy resin crude product; and 3, removing impurities in the BPA-GA novolac epoxy resin crude product and drying to obtain the BPA-GA novolac epoxy resin, wherein the BPA-GA novolac epoxy resin has the heat resistance of the bisphenol A formaldehyde novolac epoxy resin, improves the toughness of the bisphenol A novolac epoxy resin and further expands the application range of the bisphenol A.)

1. A preparation method of BPA-GA novolac epoxy resin is characterized by comprising the following steps:

step 1, uniformly mixing BPA-GA phenolic resin, epoxy chloropropane and tetrabutylammonium bromide to obtain a mixed system A, then reacting the mixed system A at 95-115 ℃, and cooling the obtained reaction liquid to 58-62 ℃ after the reaction is finished to obtain a mixed system B;

step 2, firstly adding a NaOH solution into the mixed system B, and then reacting for 0.8-1.2 h at 65-75 ℃ to obtain a BPA-GA novolac epoxy resin crude product;

and 3, removing impurities in the BPA-GA novolac epoxy resin crude product and drying to obtain the BPA-GA novolac epoxy resin.

2. The method for preparing BPA-GA phenolic epoxy resin according to claim 1, wherein in step 1, the mass ratio of BPA-GA phenolic resin, epichlorohydrin and tetrabutylammonium bromide is 20: (47.32-59.15): (0.15-0.3).

3. The method for preparing BPA-GA phenolic epoxy resin according to claim 2, wherein in step 2, the mass ratio of NaOH in NaOH solution to BPA-GA phenolic epoxy resin in step 1 is (2-3): 20.

4. the preparation method of BPA-GA novolac epoxy resin according to claim 3, wherein the mass fraction of the NaOH solution is 8-12%, and the NaOH solution is added into the mixed system B at a constant speed within 1.3-1.7 h.

5. The preparation method of BPA-GA novolac epoxy resin according to claim 1, wherein in step 1, the mixed system A reacts at the temperature for 3-4 h.

6. The preparation method of BPA-GA novolac epoxy resin according to claim 1, wherein in step 3, the BPA-GA novolac epoxy resin crude product is washed with deionized water for 3-5 times, then subjected to reduced pressure distillation at 90-100 ℃ for 45-75 min to obtain primarily purified BPA-GA novolac epoxy resin, and finally, the primarily purified BPA-GA novolac epoxy resin is sequentially purified with benzene and deionized water and dried to obtain BPA-GA novolac epoxy resin.

7. The preparation method of BPA-GA novolac epoxy resin according to claim 6, characterized in that BPA-GA novolac epoxy resin which is primarily purified is dissolved in benzene, then the solution is kept stand for 10-12 h, and finally the obtained product is extracted for 3-5 times by deionized water at 90-95 ℃ and then is subjected to reduced pressure distillation to obtain BPA-GA novolac epoxy resin.

8. The preparation method of BPA-GA novolac epoxy resin according to claim 7, wherein the ratio of the BPA-GA novolac epoxy resin subjected to primary purification to benzene is (17-20) g: (8-12) mL.

9. The preparation method of BPA-GA novolac epoxy resin according to claim 7, wherein the amount of deionized water used for each time is 80-150 mL when the obtained product is extracted with deionized water; the reduced pressure distillation is carried out at 70-100 ℃.

10. A BPA-GA novolac epoxy resin obtained by the method for preparing BPA-GA novolac epoxy resin according to any one of claims 1 to 9, wherein the structural formula of the BPA-GA novolac epoxy resin is as follows:

wherein n is equal to 4 or 5.

Technical Field

The invention belongs to the technical field of novolac epoxy resin, and particularly relates to BPA-GA novolac epoxy resin and a preparation method thereof.

Background

Bisphenol a is one of the most widely used industrial compounds in the world, its chemical name being 2, 2-bis (4-hydroxyphenyl) propane, obtained by condensation of phenol and acetone in an acidic medium. Because the plastic products are added with the bisphenol A to ensure that the plastic products have the characteristics of colorless transparency, durability, lightness and the like, the bisphenol A is used for producing fine chemical products such as plasticizers, flame retardants, heat stabilizers and the like. Phenol and formaldehyde are subjected to polycondensation reaction and then reacted with excessive epichlorohydrin to obtain the novolac epoxy resin which is mainly used for manufacturing various structural members and electrical elements. The phenolic resin needs to be further modified because of the problems of over-high curing temperature, large curing volume shrinkage, poor alkali resistance and the like during curing of the phenolic resin.

The bisphenol A type novolac epoxy resin contains more epoxy groups than bisphenol A type epoxy resin, can provide more crosslinking points, and is easier to form a highly crosslinked three-dimensional structure. In addition, the phenolic aldehyde structure is contained in the molecule, so that the composite material has excellent electrical insulation, water resistance, chemical resistance, higher glass transition temperature and thermal stability.

In article 51-53+87 from material protection 2005(12), Zhengyi' an, etc., bisphenol A and formaldehyde are firstly polycondensed to obtain bisphenol A novolac resin, and then bisphenol A novolac epoxy resin with excellent sulfur resistance and acid resistance and free phenol content far lower than the national standard requirement is obtained through epoxy modification and thermocuring. In the article of chemical engineering novel materials 2009,37(06):104-106+109, the blending modification of bisphenol A type epoxy resin (E51 and E12) and phenol type phenolic resin, such as Chenshufan, improves the corrosion resistance of phenolic resin matrix, and improves the melt fluidity and melt index of ABS system of pure phenolic resin in oxidizing acidic environment and alkaline environment. In the article of petrochemical engineering 2012,41(05):583-587, the phenolic resin is compositely modified by using bisphenol A epoxy resin E51 and organic silicon 8427 in a Douker 37090, and the like, and the phenolic epoxy resin adhesive obtained after modification has lower free formaldehyde content and obviously improved heat resistance and flexibility compared with the phenolic epoxy resin adhesive obtained before modification.

As described above, bisphenol a novolac epoxy resins are widely used and can be used as composite materials, molding materials, coatings, epoxy molding materials for chip encapsulation, epoxy intermediates, curing agents, and the like, but phenolic hydroxyl groups and methylene groups in the molecular structure of novolac epoxy resins are susceptible to high-temperature oxidation, so that the phenolic hydroxyl groups and methylene groups are affected in heat resistance, and have low ductility and high brittleness, so that further studies on the modification of bisphenol a novolac epoxy resins are necessary.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the BPA-GA novolac epoxy resin and the preparation method thereof, and the preparation method has the advantages of simplicity, low production cost, mild reaction conditions, simple operation method, less time consumption and high product purity.

The invention is realized by the following technical scheme:

a preparation method of BPA-GA novolac epoxy resin comprises the following steps:

step 1, uniformly mixing BPA-GA phenolic resin, epoxy chloropropane and tetrabutylammonium bromide to obtain a mixed system A, then reacting the mixed system A at 95-115 ℃, and cooling the obtained reaction liquid to 58-62 ℃ after the reaction is finished to obtain a mixed system B;

step 2, firstly adding a NaOH solution into the mixed system B, and then reacting for 0.8-1.2 h at 65-75 ℃ to obtain a BPA-GA novolac epoxy resin crude product;

and 3, removing impurities in the BPA-GA novolac epoxy resin crude product and drying to obtain the BPA-GA novolac epoxy resin.

Preferably, in the step 1, the mass ratio of the BPA-GA phenolic resin to the epichlorohydrin to the tetrabutylammonium bromide is 20: (47.32-59.15): (0.15-0.3).

Further, in the step 2, the mass ratio of NaOH in the NaOH solution to the BPA-GA phenolic resin in the step 1 is (2-3): 20.

further, the mass fraction of the NaOH solution is 8% -12%, and the NaOH solution is added into the mixed system B at a constant speed within 1.3-1.7 h.

Preferably, in the step 1, the mixed system A reacts for 3-4 hours at the temperature.

Preferably, in the step 3, the crude product of the BPA-GA novolac epoxy resin is washed by deionized water for 3-5 times, then is subjected to reduced pressure distillation at 90-100 ℃ for 45-75 min to obtain a primarily purified BPA-GA novolac epoxy resin, and finally the primarily purified BPA-GA novolac epoxy resin is sequentially purified by benzene and deionized water and dried to obtain the BPA-GA novolac epoxy resin.

Further, dissolving the BPA-GA novolac epoxy resin which is preliminarily purified in benzene, standing for 10-12 hours, extracting the obtained product with deionized water at 90-95 ℃ for 3-5 times, and then distilling under reduced pressure to obtain the BPA-GA novolac epoxy resin.

Further, the ratio of the BPA-GA novolac epoxy resin subjected to primary purification to benzene is (17-20) g: (8-12) mL.

Further, when the obtained product is extracted by deionized water, the using amount of the deionized water is 80-150 mL each time; the reduced pressure distillation is carried out at 70-100 ℃.

A BPA-GA novolac epoxy resin obtained by the method for preparing BPA-GA novolac epoxy resin according to any one of the preceding claims, wherein the structural formula of the BPA-GA novolac epoxy resin is as follows:

wherein n is equal to 4 or 5.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention relates to a preparation method of BPA-GA novolac epoxy resin, wherein tetrabutylammonium bromide is used as a catalyst to provide a certain acidic environment, the tetrabutylammonium bromide is mixed with BPA-GA novolac resin and epichlorohydrin to open the epichlorohydrin, the opened epichlorohydrin is subjected to grafting reaction with BPA-GA novolac resin, NaOH is added after the temperature is reduced, the temperature is raised, the product obtained by the subsequent grafting reaction is subjected to ring-closing reaction, and finally the product is separated and dried to obtain the BPA-GA novolac epoxy resin. The invention has simple treatment process, further increases the application range of the invention in the chemical industry, and has higher application value in a plurality of fields such as composite materials, molding compounds, coatings, epoxy molding compounds for chip packaging, epoxy intermediates, curing agents and the like; the raw materials of BPA-GA phenolic resin, sodium hydroxide, epichlorohydrin and tetrabutylammonium bromide have wide sources and low production cost; compared with the prior art for synthesizing the bisphenol A formaldehyde phenolic resin by using the bisphenol A and the formaldehyde, the method has the advantages of low toxicity of reactants and reaction conditions, simple operation method, no need of special instruments and low time consumption.

The BPA-GA novolac epoxy resin synthesized by the invention not only has the heat resistance of bisphenol A formaldehyde novolac epoxy resin, but also improves the toughness of the bisphenol A novolac epoxy resin, and further expands the application range of bisphenol A.

Drawings

FIG. 1 is a graph of the toughness of BPA-GA novolac epoxy resins prepared in example 1 of the present invention.

FIG. 2 is a Fourier infrared comparison of BPA-GA novolac epoxy resin and BPA-GA novolac resin prepared in example 1 of the present invention.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

The invention relates to a preparation method of BPA-GA novolac epoxy resin, wherein BPA is bisphenol A, GA is glutaraldehyde, the chemical reaction principle in the preparation process is as follows,

wherein n is equal to 4 or 5.

And carrying out grafting reaction on the BPA-GA phenolic resin and ring-opened epichlorohydrin under an acidic condition, and finally carrying out ring closure to obtain the BPA-GA phenolic epoxy resin.

The structural formula of the BPA-GA phenolic epoxy resin is as follows:

wherein n is equal to 4 or 5.

The above-mentioned BPA-GA phenolic resin Applicant has mentioned in the previous patents, and the specific preparation method comprises the following steps,

step 1, mixing a mixture of a: (5.0-5.4) mixing the bisphenol A, glutaraldehyde and a NaOH solution to obtain a mixed system A;

step 2, reacting the mixed system A at 90-100 ℃ for 5.8-6.2 h to obtain a mixed system B;

and 3, separating the product in the mixed system B and drying to obtain the BPA-GA phenolic resin.

As an example, the BPA-GA phenolic resin is obtained according to the following specific scheme,

step 1, adding 11.4g of bisphenol A and 25mL of n-butanol into a 250mL three-neck round-bottom flask with a mechanical stirrer at the same time, stirring and heating to 65 ℃ for 20min, wherein the n-butanol is used as a solvent to dissolve the solid bisphenol A to obtain a solution;

step 2, stirring the solution to be clear and transparent, cooling to room temperature, then adding 20g of 25 mass percent glutaraldehyde aqueous solution and 0.25g of 1 mass percent NaOH solution, heating to 95 ℃, reacting for 6 hours with NaOH as a catalyst to obtain a mixed system containing BPA-GA phenolic resin;

step 3, carrying out reduced pressure distillation on the mixed system obtained in the step 2 at the temperature of 95 ℃ for 1h, and removing n-butyl alcohol, water and glutaraldehyde;

step 4, dissolving the mixture obtained in the step 3 in an acetone solvent to form a mixed solution, dialyzing for 8 hours, specifically, filling the mixed solution into a dialysis bag with the molecular weight of 500, sealing two ends by using a clamp, placing the dialysis bag into a large beaker containing acetone, and stirring the acetone in the large beaker by using a magnetic stirrer to obtain an acetone solution containing BPA-GA phenolic resin;

and 5, putting the acetone solution containing the BPA-GA phenolic resin in a fume hood for 9 hours, volatilizing the solvent acetone at normal temperature, and then drying the acetone solution in a drying oven at 70 ℃ for 8 hours to obtain the BPA-GA phenolic resin.

Specifically, the invention relates to a preparation method of BPA-GA novolac epoxy resin, which comprises the following steps,

step 1, adding BPA-GA phenolic resin into a 250mL four-neck round-bottom flask with a mechanical stirrer, sequentially adding tetrabutyl ammonium bromide and epoxy chloropropane, and uniformly stirring to obtain a mixed system A, wherein the mass ratio of the BPA-GA phenolic resin to the epoxy chloropropane to the tetrabutyl ammonium bromide is 20: (47.32-59.15): (0.15 to 0.3);

step 2, heating the mixed system A while stirring, reacting for 3-4 h at 95-115 ℃, using tetrabutyl ammonium bromide as a catalyst to open the ring of epoxy chloropropane and react with BPA-GA phenolic resin, and then cooling to 58-62 ℃ to obtain a mixed system B;

and 3, dropwise adding a NaOH solution at a constant speed within 1.3-1.7 h, wherein the mass ratio of NaOH in the NaOH solution to BPA-GA phenolic resin in the step 1 is (2-3): 20, because the mass of 25mL of NaOH solution with the mass fraction of 8-12% is 2-3 g, the solution can be used for preparation in the following embodiments, the NaOH can fully perform the subsequent ring-closing reaction, and after the dropwise addition is finished, the reaction is continued for 0.8-1.2 h after the temperature is raised to 65-75 ℃, so that a BPA-GA novolac epoxy resin crude product can be obtained;

step 4, washing the BPA-GA novolac epoxy resin crude product with deionized water for 3-5 times to remove formed salts, namely partial byproducts, and then carrying out reduced pressure distillation at 90-100 ℃ for 45-75 min to remove unreacted epoxy chloropropane;

and 5, dissolving the product obtained in the step 4 in benzene, and standing for 10-12 hours, wherein the ratio of the product to the benzene is (17-20) g: (8-12) mL, continuously extracting with deionized water at 90-95 ℃ for 3-5 times, each time using 80-150 mL of deionized water, and finally, performing reduced pressure distillation at 70-100 ℃ to remove benzene and water to obtain a light brown transparent solid BPA-GA phenolic epoxy resin.