阅读说明：本技术 苯并噁嗪树脂和酚醛树脂的共聚树脂的制备方法及用其制备苯并噁嗪-酚醛模塑料的方法 (Preparation method of benzoxazine resin and phenolic resin copolymer resin and method for preparing benzoxazine-phenolic moulding plastic by using benzoxazine resin and phenolic resin copolymer resin ) 是由 曹海波 杨国华 方兵华 程国俊 于 2021-09-30 设计创作，主要内容包括：本发明公开了一种苯并噁嗪树脂和酚醛树脂的共聚树脂的制备方法及用其制备苯并噁嗪-酚醛模塑料的方法,制备一种软化点高、分子量较高的苯并噁嗪树脂和酚醛树脂的共聚树脂,采用分子量较大、软化点高的苯并噁嗪树脂和酚醛树脂的共聚树脂,采用苯并噁嗪树脂和酚醛树脂的共聚树脂与线型酚醛树脂复配,制备收缩率较低、强度高、耐冲击、环保、阻燃性能好、耐热性能好、加工性能好且对加工设备磨损低的苯并噁嗪-酚醛模塑料。本发明制备出的苯并噁嗪-酚醛模塑料可以应用于对制品尺寸、强度、耐温、阻燃性能、环保等要求高的模塑料零配件制造,特别适用于高端电器线圈骨架的制造与应用。(The invention discloses a preparation method of copolymer resin of benzoxazine resin and phenolic resin and a method for preparing a benzoxazine-phenolic moulding compound by using the copolymer resin, wherein the copolymer resin of benzoxazine resin and phenolic resin with high softening point and high molecular weight is prepared, the copolymer resin of benzoxazine resin and phenolic resin with high molecular weight and high softening point is adopted, and the copolymer resin of benzoxazine resin and phenolic resin is compounded with linear phenolic resin to prepare the benzoxazine-phenolic moulding compound with low shrinkage, high strength, impact resistance, environmental protection, good flame retardant property, good heat resistance, good processing property and low abrasion to processing equipment. The benzoxazine-phenolic moulding plastic prepared by the invention can be applied to the manufacturing of moulding plastic parts with high requirements on the size, strength, temperature resistance, flame retardant property, environmental protection and the like of products, and is particularly suitable for the manufacturing and application of high-end electrical appliance coil frameworks.)

1. A preparation method of a copolymer resin of benzoxazine resin and phenolic resin is characterized by comprising the following steps:

(1) adding 100 parts of molten phenol solution into a reaction kettle with a condensation reflux device, starting a stirrer, controlling the stirring speed to be 80-120 r/min, adding 0.5-1.5 parts of oxalic acid, controlling the temperature of materials in the reaction kettle to be 45-50 ℃, and adding 20-30 parts of paraformaldehyde with the content of 96%;

(2) after the paraformaldehyde is added, adjusting a steam valve, heating the system material to 75-85 ℃ at a heating rate of 5-6 ℃/min, reacting for 1-3 h at the temperature, heating the system material to 100-102 ℃ at a heating rate of 2-3 ℃/min after heat preservation is finished, and boiling the material for 2-4 h to obtain a mixture containing a phenolic resin prepolymer;

(3) after the boiling reaction is finished, adjusting a cooling water valve to quickly reduce the temperature of the system material to 75-85 ℃, adjusting the pH value of the system material to 8-10 by using a 10% sodium hydroxide solution, and adding 25-50 parts of an aniline solution and 17-34 parts of 96% paraformaldehyde;

(4) maintaining the temperature of the system at 75-85 ℃ by controlling a steam valve and a cooling water valve, continuously reacting for 3-5 hours at the temperature, paying attention to the change of the viscosity of the system material in the reaction process, closing a condensate reflux valve after the reaction is finished, and entering a normal-pressure dehydration stage;

(5) closing the cooling valve, adjusting the steam valve, dehydrating at normal pressure, heating the material to 110-130 ℃ within 2-3 h, and finishing dehydration at normal pressure;

(6) and starting a vacuum pump, opening a vacuum valve, starting vacuum dehydration and dephenolization, keeping the vacuum degree between-0.092 and-0.1 MPa, performing vacuum dehydration and dephenolization until the temperature of the system material reaches 140-160 ℃, sampling, and testing to obtain the copolymer resin of benzoxazine resin and phenolic resin with the softening point of 110-130 ℃ and the number average molecular weight of 800-1200.

2. A method for preparing a benzoxazine-phenolic moulding compound by using the copolymer resin prepared in the claim 1, wherein the benzoxazine-phenolic moulding compound is prepared from the following components in parts by weight: 5-15 parts of linear phenolic resin, 10-30 parts of copolymer resin of benzoxazine resin and phenolic resin, 10-25 parts of wood powder, 10-25 parts of mineral filler, 10-20 parts of flame retardant, 0.5-2.5 parts of lubricant, 0.5-1.5 parts of release agent, 0.5-1.5 parts of pigment, 1.5-3 parts of curing agent and 0.5-2.0 parts of curing accelerator.

3. The method for preparing the benzoxazine-phenolic moulding compound according to claim 2, wherein the benzoxazine-phenolic co-moulding compound is preferably prepared from the following components in parts by weight: 8-10 parts of linear phenolic resin, 20-30 parts of copolymer resin of benzoxazine resin and phenolic resin, 15-20 parts of wood powder, 15-20 parts of mineral filler, 15-20 parts of flame retardant, 1.0-1.5 parts of lubricant, 1.0-1.5 parts of release agent, 1.0-1.5 parts of pigment, 2-3 parts of curing agent and 1.0-2.0 parts of curing accelerator.

4. The method of preparing a benzoxazine-phenolic molding compound according to claim 3, wherein: the linear phenolic resin is phenolic resin catalyzed by acid, the softening point is 90-110 ℃, and the number average molecular weight is 400-800; the copolymer resin of the benzoxazine resin and the phenolic resin has a softening point of 110-130 ℃ and a number average molecular weight of 800-1200.

5. The method of preparing a benzoxazine-phenolic molding compound according to claim 3, wherein: the wood powder is sieved by a 80-mesh sieve and is completely passed through, and the balance of the sieved wood powder is less than or equal to 5 percent by a 100-mesh sieve; the mineral filler is selected from one or more of talcum powder, calcium carbonate, mica powder, wollastonite powder, kaolin or barium sulfate, and the fineness of the mineral filler is more than or equal to 300 meshes, preferably more than or equal to 800 meshes.

6. The method of preparing a benzoxazine-phenolic molding compound according to claim 3, wherein: the flame retardant is a halogen-free flame retardant and is one or more of aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, melamine cyanurate and antimony trioxide; the curing agent is urotropine; the accelerant is one or more of magnesium hydroxide, magnesium oxide and calcium hydroxide; the release agent is one or more of stearic acid, zinc stearate, magnesium stearate, calcium stearate and EBS; the lubricant is selected from one or more of polyethylene glycol-1000, polyethylene glycol-4000, polypropylene glycol-1000, polypropylene glycol-4000, polypropylene glycol-330N, stearic acid composite ester, oleamide and erucamide, PE wax and diethylene glycol dibenzoate.

7. The method of preparing a benzoxazine-phenolic molding compound according to claim 4, wherein: the preferable softening point of the novolac resin is 95-105 ℃, and the number average molecular weight of the novolac resin is 500-600.

8. The method of preparing a benzoxazine-phenolic molding compound according to claim 4, wherein: the preferable softening point of the copolymer resin of the benzoxazine resin and the phenolic resin is 120-125 ℃, and the number average molecular weight is 900-1100.

9. The method of preparing a benzoxazine-phenolic molding compound according to claim 4, wherein: the flame retardant is preferably one or two of aluminum hydroxide and magnesium hydroxide.

10. The method of preparing a benzoxazine-phenolic molding compound according to claim 4, wherein: the lubricant is preferably one or more of polyethylene glycol-1000, polyethylene glycol-4000, polypropylene glycol-1000, polypropylene glycol-4000 and polypropylene glycol-330N.

Technical Field

The invention belongs to the technical field of polymer composite materials, and particularly relates to a preparation method of a copolymer resin of benzoxazine resin and phenolic resin and a method for preparing a benzoxazine-phenolic moulding plastic by using the copolymer resin.

Background

Benzoxazine is a novel thermosetting resin containing a nitrogen-oxygen six-membered heterocyclic ring structure and is obtained by Mannich condensation reaction of an amine compound, a phenolic compound and formaldehyde. When a curing agent is added or heated, benzoxazine undergoes ring-opening curing to form a nitrogen-containing crosslinked network structure, so that the benzoxazine is also called ring-opening phenolic resin. The benzoxazine resin is used as a novel phenolic resin, inherits the advantages of the traditional phenolic resin, such as good mechanical property, heat resistance, flame retardant property, dielectric property, low price of raw materials and the like, and simultaneously, the benzoxazine forms a cross-linked three-dimensional network structure through ring-opening polymerization, so that no micromolecules are released in the curing process, the size of a product is close to zero shrinkage, and no microcrack exists. In addition, because benzoxazine has flexible molecular design, groups with cross-linking, heat resistance, flame resistance and the like are introduced by utilizing the combination of amines and phenolic compounds with various structures, the benzoxazine resin with good thermal stability, mechanical property and electrical property can be prepared, and the benzoxazine resin is widely applied to the fields of electronic packaging, advanced composite material matrix resin, ablation-resistant materials and the like. However, when the benzoxazine resin is used alone, the curing temperature is high, which is not beneficial to industrial production.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a preparation method of a benzoxazine resin and phenolic resin copolymer resin with high softening point and higher molecular weight, wherein the benzoxazine resin and phenolic resin copolymer resin are combined with the traditional linear phenolic resin to prepare a benzoxazine-phenolic moulding compound with low shrinkage, high strength, impact resistance, environmental protection, good flame retardant property, good heat resistance, good processability and low abrasion to processing equipment.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

(1) adding 100 parts of the melted phenol solution into a reaction kettle with a condensation reflux device, starting a stirrer, controlling the stirring speed to be 80-120 r/min, adding 0.5-1.5 parts of oxalic acid, controlling the temperature of the materials in the reaction kettle to be 45-50 ℃, and adding 20-30 parts of paraformaldehyde with the content of 96%.

(2) After the paraformaldehyde is added, adjusting a steam valve, raising the temperature of the system material to 75-85 ℃ at a temperature rise speed of 5-6 ℃/min, reacting for 1-3 h at the temperature, and after the heat preservation is finished, raising the temperature of the system material to 100-102 ℃ at a temperature rise speed of 2-3 ℃/min until the material is boiled for 2-4 h to obtain a mixture containing the phenolic resin prepolymer.

(3) After the boiling reaction is finished, adjusting a cooling water valve to rapidly reduce the temperature of the system material to 75-85 ℃, adjusting the pH value of the system material to 8-10 by using a 10% sodium hydroxide solution, and adding 25-50 parts of an aniline solution and 17-34 parts of 96% paraformaldehyde.

(4) The temperature of the system is maintained at 75-85 ℃ by controlling steam and cooling water valves, the reaction is continued for 3-5 hours at the temperature, the change of the viscosity of the system material is noticed in the reaction process, and after the reaction is finished, a condensate reflux valve is closed, and the normal-pressure dehydration stage is carried out.

(5) And closing the cooling valve, adjusting the steam valve, performing normal-pressure dehydration, heating the material to 110-130 ℃ within 2-3 h, and finishing the normal-pressure dehydration.

(6) And starting a vacuum pump, opening a vacuum valve, starting vacuum dehydration and dephenolization, keeping the vacuum degree between-0.092 and-0.1 MPa, performing vacuum dehydration and dephenolization until the temperature of the system material reaches 140-160 ℃, sampling, and testing to obtain the copolymer resin of benzoxazine resin and phenolic resin with the softening point of 110-130 ℃ and the number average molecular weight of 800-1200.

In the invention, further, the benzoxazine-phenolic moulding compound is prepared from the following components in parts by weight: 5-15 parts of linear phenolic resin, 10-30 parts of copolymer resin of benzoxazine resin and phenolic resin, 10-25 parts of wood powder, 10-25 parts of mineral filler, 10-20 parts of flame retardant, 0.5-2.5 parts of lubricant, 0.5-1.5 parts of release agent, 0.5-1.5 parts of pigment, 1.5-3 parts of curing agent and 0.5-2.0 parts of curing accelerator.

In the invention, further, the benzoxazine-phenolic moulding compound is preferably prepared from the following components in parts by weight: 8-10 parts of linear phenolic resin, 20-30 parts of copolymer resin of benzoxazine resin and phenolic resin, 15-20 parts of wood powder, 15-20 parts of mineral filler, 15-20 parts of flame retardant, 1.0-1.5 parts of lubricant, 1.0-1.5 parts of release agent, 1.0-1.5 parts of pigment, 2-3 parts of curing agent and 1.0-2.0 parts of curing accelerator.

In the invention, the linear phenolic resin is acid-catalyzed phenolic resin, the softening point is 90-110 ℃, and the number average molecular weight is 400-800.

In the invention, the copolymer resin of the benzoxazine resin and the phenolic resin has a softening point of 110-130 ℃ and a number average molecular weight of 800-1200.

In the invention, furthermore, the wood powder is sieved through a 80-mesh sieve and the rest is less than or equal to 5 percent through a 100-mesh sieve.

In the invention, further, the mineral filler is selected from one or more of talcum powder, calcium carbonate, mica powder, wollastonite powder, kaolin or barium sulfate, and the fineness of the mineral filler is more than or equal to 300 meshes.

In the invention, the flame retardant is a halogen-free flame retardant, and one or more of aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, melamine cyanurate and antimony trioxide are selected.

In the present invention, further, the curing agent is urotropin.

In the invention, further, the accelerant is one or more of magnesium hydroxide, magnesium oxide and calcium hydroxide. In the invention, further, the release agent is one or more of stearic acid, zinc stearate, magnesium stearate, calcium stearate and EBS.

In the invention, the lubricant is one or more selected from polyethylene glycol-1000, polyethylene glycol-4000, polypropylene glycol-1000, polypropylene glycol-4000, polypropylene glycol-330N, stearic acid complex ester, oleamide and erucamide, PE wax and diethylene glycol dibenzoate.

In the present invention, the novolac resin preferably has a softening point of 95 to 105 ℃ and a number average molecular weight of 500 to 600.

In the invention, the copolymer resin of the benzoxazine resin and the phenolic resin preferably has a softening point of 120-125 ℃ and a number average molecular weight of 900-1100.

In the present invention, the lubricant is preferably one or more of polyethylene glycol-1000, polyethylene glycol-4000, polypropylene glycol-1000, polypropylene glycol-4000, and polypropylene glycol-330N.

In the present invention, the mineral filler is preferably a mineral filler of 800 mesh or more.

In the present invention, the flame retardant is preferably one or both of aluminum hydroxide and magnesium hydroxide.

The invention has the beneficial effects that: (1) the polymerization reaction of the benzoxazine resin and the linear phenolic resin is ring-opening polymerization, small molecules are not released during polymerization, the shrinkage rate is low, and the size of the prepared molding compound product is stable.

(2) The copolymer resin of benzoxazine resin and phenolic resin with larger molecular weight and high softening point is adopted, which is beneficial to improving the mechanical properties and high temperature resistance of the molding compound, such as impact strength, bending strength and the like.

(3) By compounding the copolymer resin of the benzoxazine resin and the phenolic resin with the linear phenolic resin, the curing and forming temperature of the molding compound can be reduced, the usage amount of the hexamethylene curing agent is reduced, and the ammonia release amount and ammonia remained in the molding compound product during curing and forming of the molding compound are reduced, so that the corrosion of the ammonia to an electronic element is reduced, and the service life of the electronic element is prolonged.

(4) The benzoxazine resin and phenolic resin with large molecular weight and high softening point are compounded with the linear phenolic resin with low molecular weight and low softening point, so that when the molding compound of the screw extrusion process product is used, the molding compound is favorably plasticized, the friction damage to a screw original piece is reduced, and meanwhile, the processed molding compound has good flowing property and is favorably processed by the molding compound product at the later stage.

(5) The molding compound does not need to add inorganic fiber reinforcing materials such as glass fiber and the like in the formula, the molded plastic parts also have higher strength, and because hard fibers such as glass fiber and the like are not needed to be added, the abrasion to a screw element of a screw extruder and a screw and a grinding tool of an injection molding machine can be reduced in the preparation and use processes of the molding compound, and the service life of the devices is prolonged.

The core technology of the invention is to combine the respective advantages of benzoxazine and traditional phenolic resin to prepare a preparation method of a copolymer resin of benzoxazine resin and phenolic resin with high softening point and higher molecular weight, and the copolymer resin of benzoxazine resin and phenolic resin is combined with traditional linear phenolic resin to prepare a benzoxazine-phenolic moulding compound with lower shrinkage, high strength, impact resistance, environmental protection, good flame retardant property, good heat resistance, good processing property and low abrasion to processing equipment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below according to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

Preparation of copolymer resin of benzoxazine resin and phenolic resin

(1) Adding 100 parts of the melted phenol solution into a reaction kettle with a condensation reflux device, starting a stirrer, controlling the stirring speed to be 100r/min, adding 1.0 part of oxalic acid, controlling the temperature of the materials in the reaction kettle to be 50 +/-1 ℃, and adding 25 parts of paraformaldehyde with the content of 96%.

(2) After the paraformaldehyde is added, adjusting a steam valve, heating the system material to 80 +/-1 ℃ at a heating rate of 5-6 ℃/min, reacting for 2 hours at the temperature, and after the heat preservation is finished, heating the system material to 100-102 ℃ at a heating rate of 2-3 ℃/min until the material is boiled for 2 hours to obtain a mixture containing the phenolic resin prepolymer.

(3) After the boiling reaction is finished, the temperature of the system material is quickly reduced to 80 ℃ by adjusting a cooling water valve, the pH value of the system material is adjusted to 9.0 by using 10% sodium hydroxide solution, and 40 parts of aniline solution and 27 parts of 96% paraformaldehyde are added.

(4) The temperature of the system is maintained at 80 +/-1 ℃ by controlling steam and cooling water valves, the reaction is continued for 4 hours at the temperature, the change of the viscosity of the system materials is noticed in the reaction process, and after the reaction is finished, a condensate reflux valve is closed, and the normal-pressure dehydration stage is carried out.

(5) And closing the valve during cooling, adjusting the steam valve, performing normal-pressure dehydration, heating the material to 120 ℃ within 2-3 h, and finishing the normal-pressure dehydration.

(6) And starting a vacuum pump, opening a vacuum valve, starting vacuum dehydration and dephenolization, keeping the vacuum degree between-0.092 MPa and-0.1 MPa, performing vacuum dehydration and dephenolization until the temperature of the system material reaches 150 ℃, sampling, and testing to obtain the benzoxazine resin and phenolic resin copolymer resin with the softening point of 125.5 ℃ and the number average molecular weight of 1081.

Preparation of di, benzoxazine-phenolic moulding plastic

The benzoxazine-phenolic aldehyde molding compound is prepared from the following components in parts by weight:

10 parts of linear phenolic resin, 26 parts of copolymer resin of benzoxazine and phenolic resin, 20 parts of wood powder, 16 parts of ground calcium carbonate, 10 parts of aluminum hydroxide, 8 parts of magnesium hydroxide, 2.0 parts of ammonium polyphosphate, 40001.0 parts of polyethylene glycol-calcium stearate, 1.0 part of zinc stearate, 1.5 parts of oil-soluble aniline black, 2.5 parts of hexamethylenetetramine, 1.0 part of magnesium oxide and 0.5 part of slaked lime.

Wherein the softening point of the novolac resin is 101 ℃, and the number average molecular weight is 583; the softening point of the copolymer resin of benzoxazine and phenolic resin is 125.5 ℃, and the number average molecular weight is 1081; the wood powder is sieved by a 80-mesh sieve and is completely passed through, and the balance of the sieved wood powder is less than or equal to 3 percent by a 100-mesh sieve; the fineness of the heavy calcium carbonate is 1250 meshes.

The preparation method comprises the following steps: the preparation method comprises the steps of crushing the copolymer resin of the linear phenolic resin, the benzoxazine resin and the phenolic resin, adding the wood powder, the mineral filler, the curing agent, the accelerator, the release agent and the lubricant in proportion, slowly and uniformly mixing, then mixing and extruding on a double-screw extruder, tabletting, crushing and granulating for molding. Wherein the temperatures of the two, the two and the three zones of the double-screw extruder are respectively as follows: 90-100 ℃, 110-120 ℃ and 140-150 ℃.

Comparative example 1

The phenolic molding compound is prepared from the following components in parts by weight:

36 parts of linear phenolic resin, 20 parts of wood powder, 16 parts of heavy calcium carbonate, 10 parts of aluminum hydroxide, 8 parts of magnesium hydroxide, 2.0 parts of ammonium polyphosphate, 40001.0 parts of polyethylene glycol-40001.0 parts of calcium stearate, 0.5 part of zinc stearate, 1.5 parts of oil-soluble nigrosine, 2.5 parts of hexamethylenetetramine, 1.0 part of magnesium oxide and 0.5 part of slaked lime.

The selection of the novolac resin, the wood powder and the ground calcium carbonate was the same as in example 1.

The phenolic molding compound was also prepared in the same manner as in example 1.

The plastic product obtained by reproducing the benzoxazine-phenolic molding compound prepared according to the example 1 and the plastic product obtained by reproducing the phenolic molding compound prepared according to the comparative example 1 were subjected to performance detection and comparison, and the following data were obtained.

It can be seen that the plastic product prepared from the benzoxazine-phenolic moulding compound has greatly improved mechanical strength and temperature resistance, and the content of free ammonia in the benzoxazine-phenolic moulding compound is greatly lower than that of common phenolic moulding compound, thereby reducing the corrosion of ammonia gas to electronic elements and prolonging the service life of the electronic elements.

It should be noted that the above describes exemplifying embodiments of the invention. It will be understood by those skilled in the art, however, that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, but that various changes and modifications may be made without departing from the scope of the invention as defined by the appended claims.