CN115558065A - Epoxy vinyl ester resin for carbon fibers, prepolymer and preparation method - Google Patents
Epoxy vinyl ester resin for carbon fibers, prepolymer and preparation method Download PDFInfo
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- CN115558065A CN115558065A CN202211125629.XA CN202211125629A CN115558065A CN 115558065 A CN115558065 A CN 115558065A CN 202211125629 A CN202211125629 A CN 202211125629A CN 115558065 A CN115558065 A CN 115558065A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
- C08F283/10—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polymers containing more than one epoxy radical per molecule
- C08F283/105—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polymers containing more than one epoxy radical per molecule on to unsaturated polymers containing more than one epoxy radical per molecule
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
- C08J5/0405—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres
- C08J5/042—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres with carbon fibres
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2351/00—Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers
- C08J2351/08—Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
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- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
- C08K7/02—Fibres or whiskers
- C08K7/04—Fibres or whiskers inorganic
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Abstract
The invention belongs to the field of carbon fiber composite materials, and provides an epoxy vinyl ester resin for carbon fibers and a prepolymer thereof. The epoxy vinyl ester resin contains unsaturated double bonds and epoxy groups at the same time, and the epoxy groups can be linked with carbon fibers through chemical bonds, so that the interface performance of the epoxy vinyl ester resin and the carbon fibers is improved. On the basis, the invention also provides a carbon fiber resin composite containing the epoxy vinyl ester resin. In addition, the invention provides a preparation method of the epoxy vinyl ester resin and the prepolymer, the method has simple flow, does not contain time-consuming procedures such as distillation, purification and the like, can carry out single-batch continuous production, has low production cost and high yield, is suitable for large-scale quantitative production, and has extremely high popularization prospect.
Description
Technical Field
The invention relates to an epoxy vinyl ester resin simultaneously containing unsaturated double bonds and epoxy groups for carbon fibers, a prepolymer and a preparation method, and belongs to the field of carbon fiber composite materials.
Background
The carbon fiber has the advantages of light weight, high strength, good fatigue performance and the like, and is widely applied to the fields of wind power, ships, rail traffic, aviation, aerospace and the like. The epoxy vinyl ester resin is a molecular structure which is formed by the reaction of epoxy resin and mono-or polycarboxylic acid and contains unsaturated carbon-carbon double bonds, and has the advantages of excellent mechanical property, low viscosity, easy control of curing and the like. However, epoxy vinyl ester resins suffer from the following disadvantages: (1) the shrinkage rate is large, the epoxy vinyl ester resin contains unsaturated carbon-carbon double bonds, the carbon-carbon double bonds are changed into carbon-carbon single bonds in the curing process, the carbon-carbon double bond length is larger than the carbon-carbon single bond length, the shrinkage is generated, and the volume shrinkage rate of the resin casting body is 8-10%; (2) the carbon fiber sizing agent is mainly epoxy resin, epoxy vinyl ester resin adopts a free radical curing mechanism, epoxy resin adopts an addition or catalysis curing mechanism, and the epoxy resin have different curing mechanisms and cannot form effective connection, so that the interface performance is poor. In view of the above two reasons, the carbon fiber composite material prepared by using the epoxy vinyl ester resin has the problems of poor mechanical properties, or the separation of fibers and resin due to large shrinkage rate, and the like, and cannot fully exert the advantages of the carbon fiber properties.
At present, matrix resin used by a carbon fiber composite material is mainly epoxy resin which has large viscosity, high price and poor processability, and generally needs to be heated and cured, and a large oven or a heating mold needs to be matched for processing a large composite material workpiece, so that the cost investment is high.
Disclosure of Invention
The invention aims to solve the problem of fiber-resin phase separation caused by poor interface bonding or large shrinkage rate of carbon fibers and vinyl ester resin, and further provides an epoxy vinyl ester resin suitable for carbon fibers and a preparation method thereof.
To achieve the above object, the present invention is realized by:
the invention provides an epoxy vinyl ester resin suitable for carbon fibers, wherein the molar ratio of unsaturated double bonds to epoxy groups in the epoxy vinyl ester resin is 0.1-4.6.
Preferably, the epoxy vinyl ester resin contains CTBN chain in the resin structure; the CTBN chain structure accounts for 0.1 to 5.0 percent of the mol number of all structures.
Preferably, the epoxy vinyl ester resin is formed by crosslinking and curing a compound A, a compound B and a crosslinking monomer;
the structure of the compound A is shown as the formula (I):
wherein, the first and the second end of the pipe are connected with each other,
r1 and R2 are independently selected from
Wherein R3 is selected from H and alkyl;
the structure of the compound B is shown as the formula (II):
wherein, the first and the second end of the pipe are connected with each other,
m is an integer from 0 to 10;
r4 and R5 are independently selected from
Wherein, R6 is selected from H and alkyl.
Preferably, the crosslinking monomer is selected from one or more of styrene, vinyl toluene, methyl methacrylate, hydroxyethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, hydroxypropyl methacrylate, trimethylolpropane diacrylate and pentaerythritol triacrylate.
The invention also provides a prepolymer for preparing the epoxy vinyl ester resin, wherein the prepolymer comprises a compound A and a compound B;
the structure of the compound A is shown as the formula (I):
wherein the content of the first and second substances,
r1 and R2 are independently selected from
Wherein R3 is selected from H and alkyl;
the structure of the compound B is shown as the formula (II):
wherein the content of the first and second substances,
m is an integer from 0 to 10;
r4 and R5 are independently selected from
Wherein, R6 is selected from H and alkyl.
Preferably, the molar ratio of unsaturated double bonds to epoxy groups in the prepolymer is 0.3.
The present invention also provides a process for preparing an epoxy vinyl ester resin as claimed in any of claims 1 to 4, comprising the steps of:
(i) Reacting low molecular weight epoxy resin with CTBN to obtain a mixture 1 comprising CTBN modified epoxy resin and low molecular weight epoxy resin;
(ii) Reacting the mixture 1 with high molecular weight epoxy resin to obtain a mixture 2 comprising different types of epoxy resin;
(iii) The mixture 2 reacts with unsaturated monocarboxylic acid to obtain a prepolymer of the epoxy vinyl ester resin containing unsaturated double bonds and epoxy groups;
(iv) And curing the prepolymer and a crosslinking monomer to obtain the epoxy vinyl ester resin.
Preferably, the reaction conditions of the process include one or more of:
(1) the low molecular weight epoxy resin is bisphenol A type epoxy resin with the epoxy value of 0.48-0.58eq/100 g;
(2) the low molecular weight epoxy resin is the epoxy resin with the number average of 172-210;
(3) the high molecular weight epoxy resin is bisphenol A epoxy resin with the epoxy value of 0.10-0.47eq/100 g;
(4) the high molecular weight epoxy resin is an epoxy resin with the number average molecular weight of 210-1000;
(5) the content of acrylonitrile in the CTBN is 5-50%;
(6) in step (i), the molar ratio of low molecular weight epoxy resin to CTBN is 20;
(7) in the step (ii), the amount of the high molecular weight epoxy resin is determined according to the molar ratio of the high molecular weight epoxy resin to the low molecular weight epoxy resin in the step (i) of 0.1;
(8) in step (iii), the unsaturated monocarboxylic acid is used in a molar ratio of 0.2 to the total amount of epoxy resin used in step (i) (ii);
(9) in the step (iv), the mass ratio of the crosslinking monomer to the prepolymer is 4;
r said crosslinking monomer is selected from one or more of styrene, vinyl toluene, methyl methacrylate, hydroxyethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, hydroxypropyl methacrylate, trimethylolpropane diacrylate and pentaerythritol triacrylate.
11 said unsaturated monocarboxylic acid is selected from methacrylic acid and/or acrylic acid;
12 said step (i) is carried out at a temperature of 80-90 ℃;
13 said step (ii) is mixed at a temperature of 90-95 ℃;
14 said step (iii) is carried out at a temperature of 90 to 110 ℃;
15 said step (iv) is cured at a temperature of from 95 to 100 ℃;
16, the reaction of the step (i) also comprises a catalyst 1, wherein the catalyst 1 is one or more selected from benzyltrimethylammonium chloride, benzyltriethylammonium chloride, triphenylphosphine, aluminum chloride and ferric chloride;
17, the reaction in the step (iii) further comprises a polymerization inhibitor 1, wherein the polymerization inhibitor 1 is selected from one or more of tert-butyl hydroquinone, tert-butyl catechol, p-benzoquinone, hydroquinone and methyl hydroquinone;
18 step (iii) further comprises catalyst 2, catalyst 2 is selected from one or more of trimethylamine, pyridine, dimethylsulfide, diethylene glycol dimethyl ether, triphenylphosphine, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylamine, imidazole, 1-methylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 2 phenyl-4-methyl-5 hydroxymethylimidazole and N- (3-aminopropyl) imidazole;
and the reaction in the step (iv) 19 also comprises a polymerization inhibitor 2, wherein the polymerization inhibitor 2 is one or more selected from p-hydroxyanisole, copper naphthenate and acetylacetone.
Preferably, in the method, the first and second reaction conditions,
in the step (i), the dosage of the catalyst 1 is 0.05-0.15% of the total mass of the low molecular weight epoxy resin and the CTBN;
and/or in the step (iii), the amount of the polymerization inhibitor 1 is 0.05-0.1 percent of the total mass of the mixture 2 and the unsaturated monocarboxylic acid;
and/or in the step (iii), the amount of the catalyst 2 is 0.10-0.30% of the total mass of the mixture 2 and the unsaturated monocarboxylic acid;
and/or in the step (iv), the amount of the polymerization inhibitor 2 is 0.01-0.05% of the total mass of the prepolymer and the crosslinking monomer.
The present invention also provides a process for preparing a prepolymer of an epoxy vinyl ester resin according to claim 5 or 6, characterized in that it comprises any of the above-mentioned steps (i) to (iii).
The present invention also provides a carbon fiber resin composite characterized in that the epoxy vinyl ester resin is any one of the above epoxy vinyl ester resins.
Compared with the prior art, the technical scheme of the invention at least has the following advantages:
1. the epoxy vinyl ester resin has high strength, good flexibility and good interface performance with carbon fiber. The epoxy vinyl ester resin contains unsaturated double bonds and epoxy groups, and the epoxy groups can be linked with carbon fibers through chemical bonds, so that the interface performance of the epoxy vinyl ester resin and the carbon fibers is improved. In some preferred embodiments of the present invention, the molecular structure of the epoxy vinyl ester resin further includes a CTBN flexible segment, which improves the elongation at break of the epoxy vinyl ester resin, and further improves the deformation resistance of the resin during the curing and shrinking process, thereby preventing the resin from separating from the fiber. As shown in the embodiments of the present invention, the elongation at break of the epoxy vinyl ester resin provided by the present invention can be increased by 30% to 80% compared with that of the epoxy vinyl ester resin without CTBN modification.
2. Compared with the traditional epoxy resin, the epoxy vinyl ester resin provided by the invention has the following characteristics:
(1) the viscosity is low, the infiltration is easy, and the process performance is good;
(2) the molecular structure contains carbon-carbon unsaturated double bonds, free radical curing can be used, the release rate of the free radicals is controlled by an accelerator and an initiator, the curing can be completed at normal temperature, the curing time is controllable, and heating curing is not needed;
(3) the cost is low, and compared with the conventional epoxy resin, the cost of all raw materials such as styrene, unsaturated carboxylic acid and the like is greatly reduced by 20-30 percent;
3. the preparation method of the epoxy vinyl ester has simple flow, does not contain time-consuming procedures such as distillation, purification and the like, can carry out single-batch continuous production, has low production cost and high yield, is suitable for large-scale quantitative production, and has extremely high popularization prospect.
Drawings
Fig. 1 is a schematic diagram of a process for preparing an epoxy vinyl ester resin according to an embodiment of the present invention.
Fig. 2 is a schematic view of the combination of an epoxy vinyl ester resin and carbon fiber according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The invention provides a preparation method of an epoxy vinyl ester resin suitable for carbon fibers.
The epoxy vinyl ester resin provided by the invention is composed of epoxy vinyl ester prepolymers of a chemical formula A and a chemical formula B and a diluent monomer;
[ chemical formula A ]
As described above for formula A, EP has the following structure;
the chemical formula A is as follows, and the CTBN structure is as follows;
wherein x, y are independently selected from integers ranging from 0 to 100, and z is an integer ranging from 0 to 50;
as described above for formula a, R1 and R2 are independently selected from one of the following structures;
wherein R3 is H or alkyl;
[ chemical formula B ]
As in formula B above, m is an integer in the range of 0 to 10, R4 and R5 are independently selected from one of the following structures;
wherein R6 is H or alkyl;
the invention provides an epoxy vinyl ester resin prepared by a method comprising the following steps:
r001 reacting low molecular weight epoxy resin with liquid carboxyl-terminated butadiene-acrylonitrile rubber (CTBN), and obtaining a mixture of CTBN modified epoxy resin and low molecular weight epoxy resin, wherein the low molecular weight epoxy resin is excessive;
r002, adding high molecular weight epoxy resin into the mixture of the CTBN modified epoxy resin and the low molecular weight epoxy resin, and uniformly mixing to obtain epoxy resin mixtures of different types;
r003, reacting the epoxy resin mixture with different types with unsaturated monocarboxylic acid, and obtaining an epoxy vinyl ester resin prepolymer simultaneously containing unsaturated double bonds and epoxy groups by excessive epoxy resin;
and R004, mixing the epoxy vinyl ester resin prepolymer with a crosslinking monomer to obtain the epoxy vinyl ester resin.
Wherein the low molecular weight to CTBN molar ratio is 20; the molar ratio of the high molecular weight epoxy resin to the low molecular weight epoxy resin is 0.1-5; the molar ratio of the unsaturated monocarboxylic acid to the total amount of the epoxy resin is 0.2 to 1.6; the mass of the crosslinking monomer is 25.0-75.0% of that of the epoxy vinyl ester resin prepolymer.
FIG. 1 is a schematic diagram of an epoxy vinyl ester resin preparation process according to an embodiment of the present invention.
In the present invention, the low molecular weight epoxy resin means a bisphenol A type epoxy resin having an epoxy value of 0.48 to 0.58eq/100g and is at least one of E51 and E54.
In the present invention, the high molecular weight epoxy resin means a bisphenol A type epoxy resin having an epoxy value of 0.10 to 0.47eq/100g, and is at least one of E44, E42, E20 and E12.
In the present invention, CTBN is a liquid nitrile rubber having a carboxyl group as a terminal group, and the main component is a butadiene-acrylonitrile copolymer containing 5 to 50% of acrylonitrile and at least one of CTBN 1300 x 8, CTBN 1300 x 13, CTBN 1300 x 31 and CTBN 1300 x 162.
In the present invention, the catalyst 1 is at least one of benzyltrimethylammonium chloride, benzyltriethylammonium chloride, triphenylphosphine, aluminum chloride and ferric chloride.
In the present invention, the catalyst 2 is at least one of trimethylamine, pyridine, dimethylsulfide, diethylene glycol dimethyl ether, triphenylphosphine, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylamine, imidazole, 1-methylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 2 phenyl-4-methyl-5 hydroxymethylimidazole and N- (3-aminopropyl) imidazole.
In the invention, the polymerization inhibitor 1 is one or more of tert-butyl hydroquinone, tert-butyl catechol, p-benzoquinone, hydroquinone and methyl hydroquinone.
In the invention, the polymerization inhibitor 2 is one or more of p-hydroxyanisole, copper naphthenate and acetylacetone.
In the present invention, the unsaturated monocarboxylic acid is selected from methacrylic acid and/or acrylic acid.
The crosslinking monomer is not particularly limited as long as it can crosslink and cure with the resin base, and in some embodiments of the invention, the crosslinking monomer may be at least one of styrene, vinyl toluene, methyl methacrylate, hydroxyethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, hydroxypropyl methacrylate, trimethylolpropane diacrylate, and pentaerythritol triacrylate.
In R001, reacting low molecular weight epoxy resin with liquid carboxyl-terminated butadiene-acrylonitrile rubber (CTBN), and obtaining a mixture of CTBN modified epoxy resin and low molecular weight epoxy resin, wherein the low molecular weight epoxy resin is excessive. Epoxy groups in the epoxy resin react with carboxyl groups in CTBN under the condition of a catalyst, 2mol of epoxy resin is consumed by 1mol of CTBN, the CTBN is embedded in a newly synthesized long chain structure containing epoxy groups at 2 ends, the compatibility with the epoxy resin is good, no phase separation is generated, the toughening effect is realized, in addition, the mole number of the low molecular weight epoxy resin is far larger than that of the CTBN, most of the low molecular weight epoxy resin is remained, the viscosity is low, and the subsequent reaction is easy to perform. The method comprises the following steps:
sequentially adding CTBN and a catalyst 1 into the low molecular weight epoxy resin at the temperature of 80-90 ℃ for reaction, and stopping the reaction when the acid value reaches 0mg KOH/g to obtain a mixture of the CTBN modified epoxy resin and the low molecular weight epoxy resin;
wherein the molar ratio of low molecular weight to CTBN is 20.
Wherein the mass of the catalyst 1 is 0.05-0.15% of the sum of the mass of the low molecular weight epoxy resin and the mass of the CTBN.
In R002, the epoxy resin with high molecular weight is added into the mixture of the CTBN modified epoxy resin and the epoxy resin with low molecular weight, and the mixture is uniformly mixed to obtain the epoxy resin mixtures with different types. The main structure of the high molecular weight epoxy resin is similar to that of the low molecular weight epoxy resin, and the high molecular weight epoxy resin is bisphenol A type epoxy resin, and is different from bisphenol A chain segment in the molecular structure in high proportion, so that the resin can have excellent flexibility and mechanical property, and the high molecular weight epoxy resin and the low molecular weight epoxy resin are mixed for use to generate bimodal distribution and ensure that the resin has better wettability and mechanical property. The method comprises the following steps:
adding high molecular weight epoxy resin into the mixture of the CTBN modified epoxy resin and the low molecular weight epoxy resin at the temperature of 90-95 ℃ until the epoxy resin and the low molecular weight epoxy resin are uniformly mixed to obtain epoxy resin mixtures of different types;
wherein the high molecular weight epoxy resin comprises one or more of E44, E20 and E12, and the molar ratio of the high molecular weight epoxy resin to the low molecular weight epoxy resin is 0.1-5.
In R003, a mixture of different types of epoxy resins as described above is reacted with an unsaturated monocarboxylic acid, with an excess of epoxy resin, to give an epoxy vinyl ester resin prepolymer containing both unsaturated double bonds and epoxy groups. The unsaturated monocarboxylic acid contains unsaturated double bonds and carboxyl simultaneously, the carboxyl can react with epoxy groups, 1mol of the unsaturated monocarboxylic acid consumes 1.0mol of epoxy groups, in the invention, 2mol of epoxy groups are contained in 1mol of epoxy resin molecular structure, so 2mol of the unsaturated monocarboxylic acid can be consumed by 1mol of epoxy resin, the epoxy resin is controlled to be excessive, partial epoxy groups can be remained, the introduced unsaturated double bonds are cured by free radicals through a compound curing system, the remained epoxy groups are cured by amines or acid anhydrides, and the epoxy resin has chemical bond linkage with carbon fibers, thereby improving the interface performance. The method comprises the following steps:
adding unsaturated monocarboxylic acid into the epoxy resin mixtures of different types at 90-95 ℃, adding polymerization inhibitor 1, stirring uniformly, adding catalyst 2, heating to 105-110 ℃, and stopping reaction when the acid value reaches 6-10mg KOH/g to obtain an epoxy vinyl ester resin prepolymer containing unsaturated double bonds and epoxy groups;
wherein the molar ratio of the unsaturated monocarboxylic acid to the total amount of the epoxy resin is 0.2-1.6;
wherein the mass of the polymerization inhibitor 1 is 0.05-0.10% of the sum of the mass of the epoxy resin mixtures of different types and the mass of the unsaturated monocarboxylic acid;
wherein the mass of the catalyst 2 is 0.10-0.30% of the sum of the masses of the different epoxy resin mixtures and the unsaturated monocarboxylic acid.
And in R004, mixing the epoxy vinyl ester resin prepolymer with a crosslinking monomer to obtain the epoxy vinyl ester resin. The cross-linking monomer has low viscosity and strong diluting capability, has good compatibility with epoxy acrylate resin prepolymer, and the prepared epoxy vinyl ester has low viscosity and is well infiltrated with carbon fiber; in addition, the crosslinking monomer contains unsaturated double bonds, so that the epoxy vinyl ester resin is fully cured, no crosslinking monomer is left, and the prepared epoxy vinyl ester resin has excellent mechanical properties. The method comprises the following steps:
cooling the epoxy vinyl ester resin prepolymer to 95-100 ℃, dissolving the epoxy vinyl ester resin prepolymer in a crosslinking monomer containing a polymerization inhibitor, and uniformly mixing to obtain the epoxy vinyl ester resin;
wherein the mass of the crosslinking monomer is 25.0-75.0% of that of the epoxy vinyl ester resin prepolymer;
wherein the mass of the polymerization inhibitor 2 is 0.01-0.05% of the sum of the mass of the epoxy vinyl ester resin prepolymer and the mass of the crosslinking monomer.
The epoxy vinyl ester resin has the advantages of low viscosity, good wettability, good flexibility, excellent mechanical property, good interface property with carbon fiber and the like; the preparation method has simple flow, does not contain time-consuming procedures such as distillation, purification and the like, can carry out single-batch continuous production, has low production cost and high yield, and is suitable for large-scale quantitative production.
Hereinafter, the method for synthesizing the epoxy vinyl ester resin for carbon fibers according to the present invention will be described in detail with reference to specific examples. In the following examples, each raw material was commercially available.
Example 1
18900g of E51 epoxy resin (50mol of E51 epoxy resin, the epoxy value is 0.50-0.52eq/100 g) is put into a reaction kettle, the temperature is increased to 80-90 ℃, 3550g of CTBN 1300 x 8 (1mol of CTBN 1300 x 8) is added, and the mixture is stirred for 0.5h; adding 21.45g of triphenylphosphine catalyst, controlling the reaction temperature to be 80-90 ℃, and stopping the reaction when the acid value reaches 0mg KOH/g;
heating to 90-95 deg.C, adding 22727g of E44 epoxy resin (50mol of E44 epoxy resin with epoxy value of 0.43-0.45eq/100 g), controlling temperature at 90-95 deg.C, and stirring for 0.5h;
adding 12040g of methacrylic acid (140 mol), adding 39.4g of tert-butyl hydroquinone, heating to 90-95 ℃, adding 81.5g of triphenylphosphine, stirring for 10min, heating to 105-110 ℃, and stopping reaction when the acid value reaches 6-10mg of KOH/g;
cooling to 95-100 ℃, dissolving the prepolymer in 24150g of styrene containing 12.1g of p-hydroxyanisole, stirring for 1h, cooling to below 40 ℃, and discharging to obtain the epoxy vinyl ester resin.
In the epoxy vinyl ester resin prepolymer prepared in example 1, the molar ratio of unsaturated double bonds to epoxy groups was 2.4.
Example 2
18900g of E51 epoxy resin (50mol of E51 epoxy resin, the epoxy value is 0.50-0.52eq/100 g) is put into a reaction kettle, the temperature is increased to 80-90 ℃, 3550g of CTBN 1300 x 8 (1mol of CTBN 1300 x 8) is added, and the mixture is stirred for 0.5h; adding 21.45g of triphenylphosphine catalyst, controlling the reaction temperature to be 80-90 ℃, and stopping the reaction when the acid value reaches 0mg KOH/g;
heating to 90-95 deg.C, adding 22727g of E44 epoxy resin (50mol of E44 epoxy resin with epoxy value of 0.43-0.45eq/100 g), controlling temperature at 90-95 deg.C, and stirring for 0.5h;
adding 5160g of methacrylic acid (60 mol), adding 34.55g of tert-butylhydroquinone, heating to 90-95 ℃, adding 69.3g of triphenylphosphine, stirring for 10min, heating to 105-110 ℃, and stopping reaction when the acid value reaches 6-10mg KOH/g;
cooling to 95-100 ℃, dissolving the prepolymer in 21150g of styrene containing 10.6g of p-hydroxyanisole, stirring for 1h, cooling to below 40 ℃, and discharging to obtain the epoxy vinyl ester resin.
The difference between example 2 and example 1 is that in example 2, the amount of methacrylic acid used is small, the proportion of epoxy groups is high, and the molar ratio of unsaturated double bonds to epoxy groups in the prepared epoxy vinyl ester resin prepolymer is 0.3.
Example 3
18900g of E51 epoxy resin (50mol of E51 epoxy resin, the epoxy value is 0.50-0.52eq/100 g) is put into a reaction kettle, the temperature is increased to 80-90 ℃, 3550g of CTBN 1300 x 8 (1mol of CTBN 1300 x 8) is added, and the mixture is stirred for 0.5h; adding 21.45g of triphenylphosphine catalyst, controlling the reaction temperature to be 80-90 ℃, and stopping the reaction when the acid value reaches 0mg KOH/g;
heating to 90-95 deg.C, adding 22727g of E44 epoxy resin (50mol E44 epoxy resin, epoxy value 0.43-0.45eq/100 g), controlling temperature at 90-95 deg.C, and stirring for 0.5h;
12040g of methacrylic acid (140 mol) is added, 39.4g of tert-butyl hydroquinone is added, the temperature is raised to 90-95 ℃, 81.5g of triphenylphosphine is added, the mixture is stirred for 10min, the temperature is raised to 105-110 ℃, and the reaction is stopped when the acid value reaches 6-10mg KOH/g;
cooling to 95-100 ℃, dissolving the prepolymer in 37566g of hydroxyethyl methacrylate, wherein the styrene contains 12.1g of p-hydroxyanisole, stirring for 1h, cooling to below 40 ℃, and discharging to obtain the epoxy vinyl ester resin.
Example 3 is different from example 1 in that a high flash point crosslinking monomer is used, a low flash point crosslinking monomer such as styrene is not contained, and the epoxy vinyl ester resin prepolymer is an environment-friendly epoxy vinyl ester resin, and the molar ratio of unsaturated double bonds to epoxy groups in the prepared epoxy vinyl ester resin prepolymer is 2.4.
Example 4
18900g of E51 epoxy resin (50mol of E51 epoxy resin, the epoxy value is 0.50-0.52eq/100 g) is put into a reaction kettle, the temperature is increased to 80-90 ℃, 8875g of CTBN 1300 x 8 (2.5 mol of CTBN 1300 x 8) is added, and the mixture is stirred for 0.5h; adding 27.65g of triphenylphosphine catalyst, controlling the reaction temperature to be 80-90 ℃, and stopping the reaction when the acid value reaches 0mg KOH/g;
heating to 90-95 deg.C, adding 22727g of E44 epoxy resin (50mol E44 epoxy resin, epoxy value 0.43-0.45eq/100 g), controlling temperature at 90-95 deg.C, and stirring for 0.5h;
11834g of methacrylic acid (137.6 mol) is added, 43.7g of tert-butylhydroquinone is added, the temperature is raised to 90-95 ℃, 84.3g of triphenylphosphine is added, the mixture is stirred for 10min, the temperature is raised to 105-110 ℃, and the reaction is stopped when the acid value reaches 6-10mg KOH/g;
cooling to 95-100 ℃, dissolving the prepolymer in 30350g of styrene containing 12.8g of p-hydroxyanisole, stirring for 1h, cooling to below 40 ℃, and discharging to obtain the epoxy vinyl ester resin.
Example 4 differs from example 1 in that the CTBN addition was increased and the molar ratio of unsaturated double bonds and epoxy groups in the prepared epoxy vinyl ester resin prepolymer was 2.4.
Comparative example 1
18900g of E51 epoxy resin (50mol of E51 epoxy resin with the epoxy value of 0.50-0.52eq/100 g) is put into a reaction kettle, the temperature is raised to 90-95 ℃, 22727g of E44 epoxy resin (50mol of E44 epoxy resin with the epoxy value of 0.43-0.45eq/100 g) is added, the temperature is controlled to 90-95 ℃, and the mixture is stirred for 0.5h;
adding 12140g of methacrylic acid (141.2 mol), adding 39.4g of tert-butylhydroquinone, heating to 90-95 ℃, adding 81.5g of triphenylphosphine, stirring for 10min, heating to 105-110 ℃, and stopping the reaction when the acid value reaches 6-10mg KOH/g;
cooling to 95-100 deg.C, dissolving the prepolymer in 25210g of styrene containing 12.1g of p-hydroxyanisole, stirring for 1h, cooling to below 40 deg.C, and discharging to obtain the epoxy vinyl ester resin of comparative example 1.
The epoxy vinyl ester resin prepared in comparative example 1 was not modified with CTBN, and the molar ratio of unsaturated double bonds to epoxy groups was 2.4.
Comparative example 2
Putting 18900g E51 epoxy resin (50mol E51 epoxy resin, epoxy value is 0.50-0.52eq/100 g) into a reaction kettle, heating to 90-95 ℃, adding 22727g E44 epoxy resin (50mol E44 epoxy resin, epoxy value is 0.43-0.45eq/100 g), controlling the temperature to 90-95 ℃, and stirring for 0.5h;
adding 17200g of methacrylic acid (200 mol), adding 41.5g of tert-butylhydroquinone, heating to 90-95 ℃, adding 84.8g of triphenylphosphine, stirring for 10min, heating to 105-110 ℃, and stopping reaction when the acid value reaches 6-10mg of KOH/g;
and (3) cooling to 95-100 ℃, dissolving the prepolymer in 27550g of styrene containing 12.1g of p-hydroxyanisole, stirring for 1h, cooling to below 40 ℃, and discharging to obtain the epoxy vinyl ester resin of comparative example 2.
The epoxy vinyl ester resin prepared in comparative example 2 was not modified with CTBN, and epoxy groups in the epoxy resin were reacted, and the epoxy vinyl ester resin obtained did not contain epoxy groups.
Test examples
The epoxy vinyl ester resin carbon fiber composites obtained in the above examples 1 to 4 and comparative examples 1 to 2 were tested for 0 ° tensile strength, 0 ° compressive strength, and in-plane shear strength, and the test results are shown in table 1;
the preparation process of the carbon fiber composite material adopts a vacuum-assisted resin transfer molding process;
the carbon fiber composite material reinforced material uses T700 carbon fiber;
the resin content of the carbon fiber composite material is 40% +/-0.5%
TABLE 1 composite Performance test results for examples 1-4 and comparative examples 1-2
| Categories | Example 1 | Example 2 | Example 3 | Example 4 | Comparative example 1 | Comparative example 2 |
| Apparent mass | Superior food | Superior food | Youyou (an instant noodle) | Superior food | Good wine | Good quality |
| 0 degree tensile strength, MPa | 1718 | 1867 | 1620 | 1793 | 1574 | 1488 |
| 0 degree compressive strength, MPa | 847 | 954 | 762 | 877 | 655 | 634 |
| Interlaminar shear strength, MPa | 41.5 | 44.8 | 37.5 | 45.4 | 38.7 | 34.3 |
The volume shrinkage and tensile elongation at break of the castings of examples 1 to 4 and comparative examples 1 to 2 were measured, and the results are shown in Table 2:
TABLE 2 results of the Performance test of the castings of examples 1-4 and comparative examples 1-2
| Categories | Example 1 | Example 2 | Example 3 | Example 4 | Comparative example 1 | Comparative example 2 |
| Volume shrinkage percentage of% | 6.3 | 4.7 | 6.6 | 6.1 | 6.4 | 8.2 |
| Tensile elongation at break,% | 6.9 | 6.2 | 7.4 | 12.3 | 3.6 | 4.0 |
As can be seen from tables 1 and 2:
1. compared with the comparative examples 1 and 2, the carbon fiber composite material of examples 1 to 4 has obviously improved 0-degree tensile strength, 0-degree compression strength and in-plane shear strength;
2. the carbon fiber composite materials prepared in the examples 1 to 4 have excellent apparent quality, while the comparative examples 1 to 2 have the phenomena of phase separation of resin and fiber to different degrees, which proves that the epoxy vinyl ester resin prepared in the examples 1 to 4 and the carbon fiber have excellent interface bonding performance.
3. Compared with the comparative examples 1 and 2, the elongation at break of the cast body is obviously improved, the proportion of epoxy groups is improved, the volume shrinkage rate of the resin cast body can be effectively reduced, and the two are both beneficial to improving the performance of the carbon fiber composite material.
4. The requirements set by the technical scheme of the invention are met through the embodiments 1-4, and the prepared epoxy vinyl ester resin can be prepared by using a carbon fiber composite material.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (11)
1. An epoxy vinyl ester resin suitable for use with carbon fibers, wherein the epoxy vinyl ester resin has a molar ratio of unsaturated double bonds to epoxy groups of 0.1 to 1.4.6.
2. The epoxy vinyl ester resin according to claim 1 wherein the resin structure comprises CTBN chains; the CTBN chain structure accounts for 0.1 to 5.0 percent of the mol number of all structures.
3. The epoxy vinyl ester resin according to claim 1, wherein the epoxy vinyl ester resin is obtained by crosslinking and curing a compound A, a compound B and a crosslinking monomer;
the structure of the compound A is shown as the formula (I):
wherein, the first and the second end of the pipe are connected with each other,
r1 and R2 are independently selected from
Wherein R3 is selected from H and alkyl;
the structure of the compound B is shown as the formula (II):
wherein the content of the first and second substances,
m is an integer from 0 to 10;
r4 and R5 are independently selected from
Wherein, R6 is selected from H and alkyl.
4. The epoxy vinyl ester resin of claim 3 wherein the crosslinking monomer is selected from one or more of styrene, vinyl toluene, methyl methacrylate, hydroxyethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, hydroxypropyl methacrylate, trimethylolpropane diacrylate and pentaerythritol triacrylate.
5. A prepolymer for use in the preparation of an epoxy vinyl ester resin according to any one of claims 1 to 4, wherein the prepolymer comprises compound a and compound B;
the structure of the compound A is shown as the formula (I):
wherein the content of the first and second substances,
r1 and R2 are independently selected from
Wherein R3 is selected from H and alkyl;
the structure of the compound B is shown as the formula (II):
wherein the content of the first and second substances,
m is an integer from 0 to 10;
r4 and R5 are independently selected from
Wherein, R6 is selected from H and alkyl.
6. The prepolymer of claim 1, wherein the molar ratio of unsaturated double bonds to epoxy groups in the prepolymer is from 0.3.
7. A process for preparing the epoxy vinyl ester resin of any one of claims 1 to 4, comprising the steps of:
(i) Reacting low molecular weight epoxy resin with CTBN to obtain a mixture 1 comprising CTBN modified epoxy resin and low molecular weight epoxy resin;
(ii) Reacting the mixture 1 with a high molecular weight epoxy resin to obtain a mixture 2 comprising different types of epoxy resins;
(iii) The mixture 2 reacts with unsaturated monocarboxylic acid to obtain a prepolymer of the epoxy vinyl ester resin containing unsaturated double bonds and epoxy groups;
(iv) And curing the prepolymer and a crosslinking monomer to obtain the epoxy vinyl ester resin.
8. The method of claim 7, comprising one or more of the following conditions:
(1) the low molecular weight epoxy resin is bisphenol A epoxy resin with the epoxy value of 0.48 to 0.58eq/100 g;
(2) the low molecular weight epoxy resin is an epoxy resin with the number average molecular weight of 172-210;
(3) the high molecular weight epoxy resin is bisphenol A type epoxy resin with the epoxy value of 0.10 to 0.47eq/100 g;
(4) the high molecular weight epoxy resin is an epoxy resin with the number average molecular weight of 210-1000;
(5) the content of acrylonitrile in the CTBN is 5-50%;
(6) in step (i), the molar ratio of low molecular weight epoxy resin to CTBN is 20;
(7) in the step (ii), the amount of the high molecular weight epoxy resin is determined according to the molar ratio of the high molecular weight epoxy resin to the low molecular weight epoxy resin in the step (i) of 0.1;
(8) in step (iii), the unsaturated monocarboxylic acid is used in a molar ratio of 0.2 to the total amount of epoxy resin used in step (i) (ii);
(9) in the step (iv), the mass ratio of the crosslinking monomer to the prepolymer is 4;
r is selected from one or more of styrene, vinyl toluene, methyl methacrylate, hydroxyethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, hydroxypropyl methacrylate, trimethylolpropane diacrylate and pentaerythritol triacrylate.
11 said unsaturated monocarboxylic acid is selected from methacrylic acid and/or acrylic acid;
12 said step (i) is carried out at a temperature of 80-90 ℃;
13 said step (ii) is mixed at a temperature of 90-95 ℃;
14 said step (iii) is carried out at a temperature of 90 to 110 ℃;
15 said step (iv) is cured at a temperature of from 95 to 100 ℃;
16, the reaction of the step (i) also comprises a catalyst 1, wherein the catalyst 1 is selected from one or more of benzyltrimethylammonium chloride, benzyltriethylammonium chloride, triphenylphosphine, aluminum chloride and ferric chloride;
17, a polymerization inhibitor 1 is further included during the reaction of the step (iii), wherein the polymerization inhibitor 1 is one or more selected from tert-butyl hydroquinone, tert-butyl catechol, p-benzoquinone, hydroquinone and methyl hydroquinone;
18 step (iii) further comprises a catalyst 2, wherein the catalyst 2 is one or more selected from trimethylamine, pyridine, dimethylsulfide, diethylene glycol dimethyl ether, triphenylphosphine, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylamine, imidazole, 1-methylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and N- (3-aminopropyl) imidazole;
and the reaction in the step (iv) 19 also comprises a polymerization inhibitor 2, wherein the polymerization inhibitor 2 is one or more selected from p-hydroxyanisole, copper naphthenate and acetylacetone.
9. The method of claim 8,
in the step (i), the dosage of the catalyst 1 is 0.05-0.15% of the total mass of the low molecular weight epoxy resin and the CTBN;
and/or in the step (iii), the amount of the polymerization inhibitor 1 is 0.05-0.1% of the total mass of the mixture 2 and the unsaturated monocarboxylic acid;
and/or in the step (iii), the amount of the catalyst 2 is 0.10 to 0.30 percent of the total mass of the mixture 2 and the unsaturated monocarboxylic acid;
20 and/or in the step (iv), the amount of the polymerization inhibitor 2 is 0.01-0.05% of the total mass of the prepolymer and the crosslinking monomer.
10. A process for preparing a prepolymer of an epoxy vinyl ester resin according to claim 5 or 6, comprising steps (i) to (iii) according to any of claims 7 to 9.
11. A carbon fiber resin composite comprising carbon fiber and the epoxy vinyl ester resin of any one of claims 1-4.
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