Preparation method of amorphous low-viscosity bisphenol A cyanate prepolymer

Abstract

The invention discloses a preparation method of an amorphous low-viscosity bisphenol A cyanate prepolymer, and belongs to the technical field of high polymer material synthesizing.The preparation method comprises the steps that firstly, a bisphenol A dilute solution and a 3-chloropropyne dilute solution are mixed to react, and 3-chloropropyne modified bisphenol A is obtained; and carrying out polymerization reaction on the 3-chloropropyne modified bisphenol A and a bisphenol A cyanate ester monomer to obtain the amorphous low-viscosity bisphenol A cyanate ester prepolymer. The introduced alkyne breaks the symmetry of a triazine ring structure, destroys the regularity of the prepolymer and reduces the crystallinity, the prepared bisphenol A cyanate prepolymer is low in viscosity, the preparation method is simple in process, and a cured product prepared from the bisphenol A cyanate prepolymer is high in toughness and overcomes the problem of high brittleness.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material synthesis, and in particular relates to a method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer. Background Art

[0002] Cyanate resin is a new type of thermosetting resin developed in the 1960s, which contains two or more cyanate functional groups (-OCN) in its molecular structure. Its molecular structure is: NCO-R-OCN. Cyanate resin is widely used in the industrial field and can be used to manufacture high-strength plastic products. Due to its excellent insulation properties, it can be used to manufacture electronic components such as circuit boards and insulating materials. In addition, cyanate resin can also be used to manufacture optical materials such as eyeglass lenses and camera lenses. Cyanate resin is also widely used in daily necessities, such as plastic bottles and plastic bags. Due to its good heat resistance, it is used to manufacture microwave food packaging, such as baby bottles and tableware.

[0003] The most common type of cyanate resin is bisphenol A cyanate resin, which has a simple synthesis process and cheap raw materials. Bisphenol A cyanate prepolymer is mainly used to prepare bisphenol A cyanate resin. Bisphenol A cyanate prepolymer is a common polymer compound, also known as BPA cyanate prepolymer, which is synthesized by polymerization reaction of bisphenol A (BPA) and cyanate monomer.

[0004] Since the triazine ring structure in the molecule of bisphenol A cyanate prepolymer is highly symmetrical, the crystallinity is high, the viscosity is high, and the fluidity is poor, the cured resin prepared from it is relatively brittle, the drapeability of the composite material prepreg obtained is poor, and the cross-linking density after the monomer polymerization is high. Therefore, modification is needed to solve the problems existing in bisphenol A cyanate prepolymer. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer. The bisphenol A cyanate prepolymer prepared by the method has low viscosity and a cured product obtained from the bisphenol A cyanate prepolymer has strong toughness.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The present invention provides a method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer, comprising the following steps:

[0008] Step 1, dissolving bisphenol A in an organic solvent to obtain a 0.1-0.5 mol / mL solution A, and adding 3-chloropropyne to the organic solvent to obtain a 0.001-0.005 mol / mL solution B;

[0009] Step 2: Place solution A in a flask, add potassium carbonate, mix well and heat to 30-50°C, slowly add solution B with stirring according to the molar ratio of bisphenol A: 3-chloropropyne = 1-2:1, react with stirring for 30-55 minutes, evaporate to remove acetone, wash and purify by chromatography to obtain 3-chloropropyne modified bisphenol A;

[0010] Step 3: Melt the bisphenol A cyanate monomer and add it into a reactor. Add 3-chloropropyne-modified bisphenol A and a catalyst into the reactor. The mass ratio of bisphenol A cyanate monomer to 3-chloropropyne-modified bisphenol A is 2.5-4.5:1. After heating reaction, a non-crystalline low-viscosity bisphenol A cyanate prepolymer is obtained.

[0011] The reaction equation in step 2 includes:

[0012]

[0013] Furthermore, in step 1, the organic solvent is one of acetone and ethanol.

[0014] Furthermore, in step 2, the potassium carbonate is in a molar ratio of potassium carbonate: bisphenol A = 1-3:1.

[0015] Furthermore, in step 2, the addition rate of solution B is 1-5 mL / min.

[0016] Furthermore, in step 2, the chromatography purification is performed by column chromatography using a mixture of n-hexane and ethyl acetate as an eluent.

[0017] Furthermore, in step three, the catalyst is one of triethylamine and tripropylamine.

[0018] Furthermore, in step three, the catalyst is added according to a molar ratio of catalyst to bisphenol A cyanate monomer of 0.4-0.6:1.

[0019] Furthermore, in step three, the temperature of the heating reaction is 160-200° C., and the reaction time is 1-1.5 h.

[0020] Beneficial effects of the present invention:

[0021] The invention introduces alkynes into bisphenol A to form modified bisphenol A by controlling substitution reaction conditions, and then obtains bisphenol A cyanate prepolymer by polymerization reaction of modified bisphenol A and bisphenol A cyanate monomer. Since the introduced alkynes break the symmetry of the triazine ring structure, the regularity of the prepolymer is destroyed, and the crystallinity is reduced, the preparation method is simple, and the prepared bisphenol A cyanate prepolymer has low viscosity. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of 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.

[0023] Example 1

[0024] Step 1, dissolving bisphenol A in acetone to obtain 0.1 mol / mL solution A, and adding 3-chloropropyne to acetone to obtain 0.001 mol / mL solution B;

[0025] Step 2, place solution A in a flask, add potassium carbonate according to the molar ratio of potassium carbonate: bisphenol A = 1:1, mix well and heat to 50°C, slowly add solution B according to the molar ratio of bisphenol A: 3-chloropropyne = 1:1 while stirring, the addition rate of solution B is 5mL / min, stir and react for 30min, evaporate to remove acetone, wash and purify by chromatography with a mixture of n-hexane and ethyl acetate (volume ratio 4:1) as eluent to obtain 3-chloropropyne modified bisphenol A;

[0026] Step 3: Melt the bisphenol A cyanate monomer and add it into a reactor. Add 3-chloropropyne-modified bisphenol A and triethylamine into the reactor. The mass ratio of bisphenol A cyanate monomer and 3-chloropropyne-modified bisphenol A is 2.5:1, and the molar ratio of triethylamine and bisphenol A cyanate monomer is 0.4:1. Heat the reaction at 160°C for 1 hour to obtain a non-crystalline low-viscosity bisphenol A cyanate prepolymer.

[0027] Example 2

[0028] The difference from Example 1 is that the molar ratio of bisphenol A:3-chloropropyne is adjusted to 1.5:1, and the other steps and conditions are the same as Example 1.

[0029] Example 3

[0030] The difference from Example 1 is that the molar ratio of bisphenol A:3-chloropropyne is adjusted to 2:1, and the other steps and conditions are the same as in Example 1.

[0031] Example 4

[0032] The difference from Example 2 is that the mass ratio of bisphenol A cyanate monomer and 3-chloropropyne modified bisphenol A is adjusted to 3.5:1, and the other steps and conditions are the same as Example 2.

[0033] Example 5

[0034] The difference from Example 2 is that the mass ratio of bisphenol A cyanate monomer and 3-chloropropyne modified bisphenol A is adjusted to 4.5:1, and the other steps and conditions are the same as Example 2.

[0035] Example 6

[0036] The difference from Example 4 is that in step 2, after uniform mixing, the heating temperature is adjusted to 40° C., and the reaction is stirred for 45 minutes. The other steps and conditions are the same as in Example 4.

[0037] Example 7

[0038] The difference from Example 4 is that in step 2, after uniform mixing, the heating temperature is adjusted to 30° C., and the reaction is stirred for 55 minutes. The other steps and conditions are the same as in Example 4.

[0039] Comparative Example 1

[0040] The prepolymer was prepared according to the preparation method in Example 3 of patent publication number CN103145983A.

[0041] The prepolymers prepared in Examples 1 to 7 and Comparative Example 1 were tested for performance, and the results are shown in Table 1:

[0042] The melt viscosity test was performed by melting the prepolymer at 130°C and measuring it using a rotary viscometer;

[0043] The glass transition temperature was detected by DSC;

[0044] Tensile strength and elongation test: The prepolymer is poured into a mold, and after curing, a casting is obtained, and the tensile strength and elongation of the casting are tested.

[0045] Table 1

[0046]

[0047] It can be seen from Table 1 that the prepolymer prepared in the embodiment under the polymerization reaction conditions of introducing alkyne has a lower viscosity, and the casting body prepared from the prepolymer also has better toughness.

[0048] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0049] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer, characterized in that: The following steps are involved: Step 1, dissolving bisphenol A in an organic solvent to obtain a 0.1-0.5 mol / mL solution A, and adding 3-chloropropyne to the organic solvent to obtain a 0.001-0.005 mol / mL solution B; Step 2: Place solution A in a flask, add potassium carbonate, mix well and heat to 30-50°C, slowly add solution B with stirring according to the molar ratio of bisphenol A: 3-chloropropyne = 1-2:1, react with stirring for 30-55 minutes, evaporate to remove acetone, wash and purify by chromatography to obtain 3-chloropropyne modified bisphenol A; Step 3: Melt the bisphenol A cyanate monomer and add it into a reactor. Add 3-chloropropyne-modified bisphenol A and a catalyst into the reactor. The mass ratio of bisphenol A cyanate monomer to 3-chloropropyne-modified bisphenol A is 2.5-4.5:

1. After heating reaction, a non-crystalline low-viscosity bisphenol A cyanate prepolymer is obtained.

2. The method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer according to claim 1, characterized in that: In step 1, the organic solvent is one of acetone and ethanol.

3. The method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer according to claim 1, characterized in that: In step 2, the potassium carbonate is prepared in a molar ratio of potassium carbonate: bisphenol A = 1-3:

1.

4. The method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer according to claim 1, characterized in that: In step 2, the addition rate of solution B is 1-5 mL / min.

5. The method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer according to claim 1, characterized in that: In step 2, the chromatography purification is performed by column chromatography using a mixture of n-hexane and ethyl acetate as an eluent.

6. The method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer according to claim 1, characterized in that: In step 3, the catalyst is one of triethylamine and tripropylamine.

7. The method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer according to claim 1, characterized in that: In step three, the catalyst is added according to a molar ratio of catalyst to bisphenol A cyanate monomer of 0.4-0.6:

1.

8. The method for preparing a non-crystalline low-viscosity bisphenol A cyanate prepolymer according to claim 1, characterized in that: In step 3, the heating reaction temperature is 160-200° C., and the reaction time is 1-1.5 h.

Images