Unsaturated polyester as well as preparation method and application thereof

Abstract

The invention provides unsaturated polyester as well as a preparation method and application thereof. The unsaturated polyester comprises a structural unit derived from an amide monomer and a structural unit derived from an imide monomer. When the unsaturated polyester provided by the invention is applied to the impregnating varnish, the bonding capacity, the mechanical property, the heat resistance and the oil resistance of the impregnating varnish can be improved, so that the application of the impregnating varnish in the fields of vehicle motors and the like is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of organic materials, and in particular to unsaturated polyesters and preparation methods and applications thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, the demand for automotive motors has surged. In order to extend the service life of automotive motors, impregnation varnish is usually used to form a paint protective layer on the surface of the stator winding of the automotive motor. At present, the main resin of the impregnation varnish is generally unsaturated polyester. In the related art, the heat resistance and oil resistance of the impregnation varnish are improved by introducing an imide group into the unsaturated polyester, but the bonding force of the impregnation varnish decreases; the bonding ability of the unsaturated polyester in the impregnation varnish is improved by introducing a hydroxyl or amide group into the unsaturated polyester of the impregnation varnish, but its heat resistance is insufficient. The low bonding ability and mechanical properties of the impregnation varnish will cause the paint layer to fall off when the motor is running at high speed; the insufficient heat resistance and oil resistance of the impregnation varnish will increase the motor power and generate too much heat in the motor, which will affect the reliability and service life of the motor. Therefore, it is necessary to provide an unsaturated polyester that can improve the bonding ability, mechanical properties, heat resistance and oil resistance of the impregnation varnish. Summary of the invention

[0003] In view of this, the present application provides an unsaturated polyester and a preparation method and application thereof. The unsaturated polyester includes a structural unit derived from an amide monomer and a structural unit derived from an imide monomer. The unsaturated polyester is used for impregnating varnish, which can improve the adhesion, mechanical properties, heat resistance and oil resistance of the impregnating varnish, thereby facilitating the application of the impregnating varnish in the fields of automotive motors and the like.

[0004] In a first aspect, the present application provides an unsaturated polyester, wherein the unsaturated polyester comprises a structural unit derived from an amide monomer and a structural unit derived from an imide monomer.

[0005] Optionally, the structural unit derived from the amide monomer includes

[0006] At least one of .

[0007] Optionally, R1, R2 and R3 are independently selected from a substituted or unsubstituted divalent alkyl group (ie, an alkylene group), a substituted or unsubstituted divalent aromatic group, or a substituted or unsubstituted divalent alicyclic group.

[0008] Optionally, the structural unit derived from the imide monomer includes

[0009]

[0010] At least one of .

[0011] Optional, R 1 , R 2 , R 4 , R 6 and R 8 are independently selected from substituted or unsubstituted divalent alkyl groups, substituted or unsubstituted divalent aromatic groups, or substituted or unsubstituted divalent alicyclic groups, R 3 and R 5 are independently selected from substituted or unsubstituted trivalent alkyl (i.e., alkylidene), substituted or unsubstituted trivalent aryl, or substituted or unsubstituted trivalent alicyclic, R 7 is selected from a carbon atom, a substituted or unsubstituted tetravalent aromatic group, or a substituted or unsubstituted tetravalent alicyclic group.

[0012] Optionally, the substituents in the substituted or unsubstituted divalent alkyl, the substituted or unsubstituted divalent aromatic group, the substituted or unsubstituted divalent alicyclic group, the substituted or unsubstituted trivalent alkyl, the substituted or unsubstituted trivalent aromatic group, the substituted or unsubstituted trivalent alicyclic group, the substituted or unsubstituted tetravalent aromatic group, and the substituted or unsubstituted tetravalent alicyclic group include at least one of a halogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a hydroxyl group, a nitro group, an amine group, a thiol group, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted aryloxy group.

[0013] Optionally, the weight proportion of the structural unit derived from the amide monomer is 3 parts to 9 parts.

[0014] Optionally, the weight proportion of the structural unit derived from the imide monomer is 13 parts to 20 parts.

[0015] Optionally, the unsaturated polyester further comprises a linking structural unit, wherein the linking structural unit comprises a linking structural unit monomer derived from an alcohol and at least one linking structural unit monomer derived from an anhydride and an acid.

[0016] Optionally, the weight proportion of the connecting structure unit is 18 parts to 71 parts.

[0017] Optionally, the acid comprises an unsaturated acid, and the unsaturated acid comprises at least one of maleic acid and fumaric acid.

[0018] Optionally, the acid anhydride includes an unsaturated acid anhydride, and the unsaturated acid anhydride includes at least one of maleic anhydride and fumaric anhydride.

[0019] Optionally, the alcohol includes at least one of a polyol and a monool, the polyol includes at least one of polyether polyol, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, 1,3-butylene glycol, butanediol and neopentyl glycol, and the monool includes at least one of benzyl alcohol, p-cresol and cyclohexyl alcohol.

[0020] Optionally, the weight average molecular weight of the unsaturated polyester is 1000-5000.

[0021] The unsaturated polyester provided in the present application includes structural units of amide monomers and structural units derived from imide monomers, which is beneficial to improving the bonding ability, mechanical properties, heat resistance and oil resistance of the impregnating varnish, and is beneficial to the application of the impregnating varnish in the field of automotive motors.

[0022] In a second aspect, the present application provides a method for preparing an unsaturated polyester, comprising:

[0023] The amide monomer and the imide monomer are mixed to obtain a mixed solution, and unsaturated polyester is obtained after reaction.

[0024] Optionally, the amide monomer includes

[0025] At least one of, R1, R2 and R3 are independently selected from a substituted or unsubstituted divalent alkyl group, a substituted or unsubstituted divalent aromatic group, or a substituted or unsubstituted divalent alicyclic group.

[0026] Optionally, the imide monomer includes

[0027] At least one of .

[0028] Optional, R 1 , R 2 , R 4 , R 6 and R 8 are independently selected from substituted or unsubstituted divalent alkyl groups, substituted or unsubstituted divalent aromatic groups, or substituted or unsubstituted divalent alicyclic groups, R 3 and R 5 are independently selected from substituted or unsubstituted trivalent alkyl, substituted or unsubstituted trivalent aryl, or substituted or unsubstituted trivalent alicyclic group, R 7 is selected from a carbon atom, a substituted or unsubstituted tetravalent aromatic group, and a substituted or unsubstituted tetravalent alicyclic group.

[0029] Optionally, the reaction temperature is 185°C-205°C, and the reaction time is 15h-25h.

[0030] Optionally, the method further comprises mixing the connecting structure unit monomer with the amide monomer and the imide monomer to obtain the mixed solution.

[0031] Optionally, the linking structural unit monomer includes alcohol, and at least one of anhydride and acid.

[0032] Optionally, the weight proportion of the amide monomer in the mixed solution is 3 parts to 9 parts, and the weight proportion of the imide monomer is 13 parts to 20 parts.

[0033] Optionally, the weight proportion of the connecting structure unit monomer is 18 parts to 71 parts.

[0034] The preparation method of the unsaturated polyester provided in the present application is novel and the preparation process is simple. The prepared unsaturated polyester can improve the bonding ability and mechanical properties of the impregnating varnish and enhance the heat resistance and oil resistance of the impregnating varnish.

[0035] In a third aspect, the present application provides the use of the unsaturated polyester described in the first aspect or the unsaturated polyester prepared by the preparation method described in the second aspect in the fields of plastics, artificial stones, fibers or paints.

[0036] The unsaturated polyester provided in the present application has a wide range of application scenarios, which is conducive to its industrial application.

[0037] In a fourth aspect, the present application provides an impregnation varnish, wherein the impregnation varnish comprises the unsaturated polyester described in the first aspect or the unsaturated polyester prepared by the preparation method described in the second aspect.

[0038] Optionally, the impregnation varnish further comprises a reactive diluent, an initiator and an inhibitor.

[0039] Optionally, in the impregnating varnish, the weight proportion of the unsaturated polyester is 40 parts to 70 parts.

[0040] Optionally, in the impregnating varnish, the weight portion of the active diluent is 30 parts to 60 parts, the weight portion of the initiator is 0.5 parts to 5 parts, and the weight portion of the inhibitor is 0.01 parts to 0.1 parts.

[0041] The impregnating varnish provided by the present application has strong bonding ability, good oil resistance and heat resistance, high mechanical strength, and improves the comprehensive performance of the impregnating varnish.

[0042] In a fifth aspect, the present application provides a motor, comprising a motor stator winding and a paint layer provided on the motor stator winding, wherein the paint layer is formed by the impregnating paint described in the fourth aspect.

[0043] The motor provided by the present application has good insulation performance, good heat resistance and high mechanical strength, which is beneficial to extending the service life of the motor.

[0044] In a sixth aspect, the present application provides a vehicle, comprising the motor described in the fifth aspect.

[0045] The vehicle provided by this application has excellent comprehensive performance, greatly improved safety performance, and strong product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the prior art description. The specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0047] Figure 1 This is an infrared spectrum test chart of the dipping varnish provided in Example 1 of the present application;

[0048] Figure 2 This is an infrared spectrum test chart of the dipping paint provided in Comparative Example 1 of the present application;

[0049] Figure 3 This is an infrared spectrum test chart of the dipping paint provided in Comparative Example 2 of the present application;

[0050] Figure 4 This is an infrared spectrum test chart of the dipping paint provided in Comparative Example 3 of the present application;

[0051] Figure 5 This is a thermogravimetric analysis diagram of the impregnating varnish after curing provided in Example 1, Example 7 and Comparative Examples 1-3 of the present application. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] The present application provides an unsaturated polyester, including structural units derived from amide monomers and structural units derived from imide monomers. In the present application, when the unsaturated polyester is used in the dipping varnish, the structural units derived from the amide monomers are easy to form hydrogen bonds with the substrate, thereby improving the bonding ability and mechanical strength of the dipping varnish, and the structural units derived from the imide monomers have large bond energy, strong rigidity, and high stability, thereby improving the mechanical strength, heat resistance, and oil resistance of the dipping varnish. The unsaturated polyester provided in the present application can improve the bonding force and mechanical strength of the dipping varnish, improve heat resistance and oil resistance, and have excellent comprehensive performance.

[0054] In the present application, the structural unit derived from the amide monomer is conducive to forming hydrogen bonds with the substrate, increasing the bonding ability and mechanical strength of the impregnating varnish. Specifically, the structural unit derived from the amide monomer may include but is not limited to

[0055]

[0056] In some embodiments, the unsaturated polyester includes a structural unit derived from an amide monomer; in other embodiments, the unsaturated polyester includes multiple (two or more) structural units derived from amide monomers. In one embodiment of the present application, the structural unit derived from the amide monomer can be In another embodiment of the present application, the structural unit derived from the amide monomer may include

[0057] In some embodiments, the structural units derived from amide monomers are all of the same structure. In other embodiments, the structural units derived from amide monomers include multiple structural units derived from amide monomers of different structures, and the number of the multiple structural units derived from amide monomers of different structures may be the same or different.

[0058] In one embodiment of the present application, the weight proportion of the structural unit derived from the amide monomer is 3-9 parts, and an appropriate amount of the structural unit derived from the amide monomer can improve the bonding ability and mechanical properties of the dipping paint. Specifically, the weight proportion of the structural unit derived from the amide monomer can be, but is not limited to, 3, 4, 5, 6, 7, 8 or 9 parts. In one embodiment of the present application, the weight proportion of the structural unit derived from the amide monomer can be 3-7 parts. In another embodiment of the present application, the weight proportion of the structural unit derived from the amide monomer can be 5-9 parts.

[0059] In one embodiment of the present application, R1, R2 and R3 are independently selected from substituted or unsubstituted divalent alkyl, substituted or unsubstituted divalent aryl or substituted or unsubstituted divalent alicyclic group. R1, R2 and R3 can be the same group or different groups. In one embodiment of the present application, R1 and R2 are alkyl, and R3 can be a divalent aryl. In another embodiment of the present application, R1, R2 and R3 can be a divalent alicyclic group.

[0060] In one embodiment of the present application, the structural unit derived from the imide monomer has an imide structure, which has large bond energy, high stability, and strong rigidity, and can improve the mechanical strength, heat resistance, and oil resistance of the unsaturated polyester. The structural unit derived from the imide monomer may include but is not limited to

[0061]

[0062] In one embodiment of the present application, the structural unit derived from the imide monomer can be In this case, the structural unit derived from the imide monomer is a monofunctional unit and can be used as an end-capping group of the unsaturated polyester. In some embodiments, the unsaturated polyester includes one structural unit derived from an imide monomer; in other embodiments, the unsaturated polyester includes multiple (two or more) structural units derived from imide monomers.

[0063] In some embodiments, the structural units derived from imide monomers are all of the same structure. In other embodiments, the structural units derived from imide monomers include a plurality of structural units derived from imide monomers of different structures, and the number of structural units derived from imide monomers of different structures may be the same or different.

[0064] In one embodiment of the present application, the weight parts of the structural unit derived from the imide monomer are 13 parts to 20 parts, and an appropriate amount of the structural unit derived from the imide monomer can improve the heat resistance and oil resistance of the impregnating varnish. Specifically, the weight parts of the structural unit derived from the imide monomer can be, but not limited to, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, etc. In one embodiment of the present application, the weight parts of the structural unit derived from the imide monomer can be 13 parts to 18 parts. In another embodiment of the present application, the weight parts of the structural unit derived from the imide monomer can be 16 parts to 20 parts.

[0065] In one embodiment of the present application, R 1 , R 2 , R 4 , R 6 and R 8 are independently selected from substituted or unsubstituted divalent alkyl groups, substituted or unsubstituted divalent aromatic groups, or substituted or unsubstituted divalent alicyclic groups, R 3 and R 5 are independently selected from substituted or unsubstituted trivalent alkyl, substituted or unsubstituted trivalent aryl, or substituted or unsubstituted trivalent alicyclic group, R 7 is selected from carbon atoms, substituted or unsubstituted tetravalent aromatic groups, and substituted or unsubstituted tetravalent alicyclic groups. 1 , R 2 , R 4 , R 6 and R 8They can be the same group or different groups; R 3 and R 5 They may be the same group or different groups.

[0066] In one embodiment of the present application, the number of carbon atoms of the divalent alkyl group is 1-18, and may include a straight-chain divalent alkyl group and a branched divalent alkyl group. Specifically, the number of carbon atoms of the divalent alkyl group may be, but is not limited to, 1, 2, 3, 4, 6, 8, 10, 12, 14, 16 or 18, etc.; illustratively, the divalent alkyl group may include, but is not limited to, at least one of -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2- and -CH2CH2CH2CH2CH2CH2-. In one embodiment of the present application, the divalent alkyl group may be -CH2CH2CH2CH2-. In another embodiment of the present application, the alkyl group may be -CH2CH2-.

[0067] In one embodiment of the present application, the trivalent alkyl group has 1 to 18 carbon atoms, and may include a straight-chain trivalent alkyl group and a branched trivalent alkyl group. Specifically, the trivalent alkyl group may have, but is not limited to, 1, 4, 6, 8, 10, 12, 14, 16 or 18 carbon atoms, etc.; illustratively, the trivalent alkyl group may include, but is not limited to, wait.

[0068] In one embodiment of the present application, the number of carbon atoms of the divalent aromatic group is 6-30. Specifically, the number of carbon atoms of the divalent aromatic group may be, but not limited to, 6, 10, 12, 14, 18, 22, 24, 26 or 30, etc.; illustratively, the divalent aromatic group may include, but not limited to, at least one of a divalent phenyl group, a divalent naphthyl group, a divalent anthracene group, a divalent tetraphenyl group, a divalent pentacene group and a divalent tetrahydronaphthyl group. In one embodiment of the present application, the divalent aromatic group may be a divalent anthracene group. In another embodiment of the present application, the divalent aromatic group may be a divalent phenyl group.

[0069] In one embodiment of the present application, the trivalent aryl group has 6-30 carbon atoms. Specifically, the trivalent aryl group may have, but is not limited to, 6, 10, 12, 14, 18, 22, 24, 26 or 30 carbon atoms, etc.; the trivalent aryl group may include, but is not limited to, at least one of a trivalent phenyl group, a trivalent naphthyl group, a trivalent anthracene group, a trivalent tetraphenyl group, a trivalent pentacene group and a trivalent tetrahydronaphthyl group. In one embodiment of the present application, the trivalent aryl group may be a trivalent anthracene group. In another embodiment of the present application, the trivalent aryl group may be a trivalent phenyl group.

[0070] In one embodiment of the present application, the carbon number of the tetravalent aryl group is 6-30. Specifically, the carbon number of the tetravalent aryl group may be, but is not limited to, 6, 10, 12, 14, 18, 22, 24, 26 or 30, etc.; the tetravalent aryl group may include, but is not limited to, at least one of a tetravalent phenyl group, a tetravalent naphthyl group, a tetravalent anthracene group, a tetravalent tetraphenyl group, a tetravalent pentacene group and a tetravalent tetrahydronaphthyl group. In one embodiment of the present application, the tetravalent aryl group may be a tetravalent anthracene group. In another embodiment of the present application, the tetravalent aryl group may be a tetravalent phenyl group.

[0071] The divalent alicyclic group is a divalent alicyclic group. In one embodiment of the present application, the number of carbon atoms of the divalent alicyclic group is 3-30. Specifically, the number of carbon atoms of the divalent alicyclic group may be, but is not limited to, 3, 5, 9, 10, 13, 15, 18, 23, 26 or 30, etc., and illustratively, the divalent alicyclic group may include, but is not limited to, at least one of a divalent cyclopropane group, a divalent cyclobutane group, a divalent cyclopentane group, a divalent cyclohexane group and a divalent cyclopentenyl group. In one embodiment of the present application, the divalent alicyclic group may be a divalent cyclopropane group. In another embodiment of the present application, the divalent alicyclic group may be a divalent cyclopentane group.

[0072] In one embodiment of the present application, the trivalent alicyclic group has a carbon number of 3-30. Specifically, the trivalent alicyclic group may have a carbon number of, but not limited to, 3, 5, 9, 10, 13, 15, 18, 23, 26 or 30, etc. For example, the trivalent alicyclic group may include, but not limited to, at least one of a trivalent cyclopropane group, a trivalent cyclobutane group, a trivalent cyclopentane group, a trivalent cyclohexane group and a trivalent cyclopentenyl group. In one embodiment of the present application, the trivalent alicyclic group may be a trivalent cyclopropane group. In another embodiment of the present application, the trivalent alicyclic group may be a trivalent cyclopentane group.

[0073] In one embodiment of the present application, the carbon number of the tetravalent alicyclic group is 3-30. Specifically, the carbon number of the tetravalent alicyclic group may be, but is not limited to, 3, 5, 9, 10, 13, 15, 18, 23, 26 or 30, etc., and illustratively, the tetravalent alicyclic group may include, but is not limited to, at least one of a tetravalent cyclopropane group, a tetravalent cyclobutane group, a tetravalent cyclopentane group, a tetravalent cyclohexane group and a tetravalent cyclopentenyl group. In one embodiment of the present application, the tetravalent alicyclic group may be a tetravalent cyclopropane group. In another embodiment of the present application, the tetravalent alicyclic group may be a tetravalent cyclopentane group.

[0074] In one embodiment of the present application, the substituents in the substituted or unsubstituted divalent alkyl group, the substituted or unsubstituted divalent aromatic group, the substituted or unsubstituted divalent alicyclic group, the substituted or unsubstituted trivalent alkyl group, the substituted or unsubstituted trivalent aromatic group, the substituted or unsubstituted trivalent alicyclic group, the substituted or unsubstituted tetravalent aromatic group, and the substituted or unsubstituted tetravalent alicyclic group may include but are not limited to at least one of halogen, nitrogen atom, oxygen atom, sulfur atom, hydroxyl group, nitro group, amine group, thiol group, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aromatic group, and substituted or unsubstituted aryloxy group.

[0075] In one embodiment of the present application, the unsaturated polyester further comprises a connecting structural unit, which can connect the structural unit derived from the amide monomer and the structural unit derived from the imide monomer. The connecting structural unit comprises a connecting structural unit monomer derived from an alcohol, and a connecting structural unit monomer derived from at least one of an anhydride and an acid.

[0076] In one embodiment of the present application, the weight parts of the connecting structure unit are 18 parts to 71 parts. Specifically, the weight parts of the connecting structure unit can be, but not limited to, 18 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 68 parts or 71 parts. In one embodiment of the present application, the weight parts of the connecting structure unit can be 18 parts to 50 parts. In another embodiment of the present application, the weight parts of the connecting structure unit can be 45 parts to 71 parts.

[0077] In one embodiment of the present application, the acid includes an unsaturated acid. Specifically, the unsaturated acid may include, but is not limited to, at least one of maleic acid and fumaric acid. In one embodiment of the present application, when the acid is an unsaturated acid, the unsaturated acid may be maleic acid, and maleic acid is used as a connecting structural unit monomer to form an unsaturated polyester.

[0078] In one embodiment of the present application, the acid further comprises a saturated acid. Specifically, the saturated acid may include, but is not limited to, at least one of terephthalic acid, isophthalic acid, adipic acid and succinic acid. In one embodiment of the present application, when the acid is a saturated acid, the saturated acid may be succinic acid.

[0079] In one embodiment of the present application, the acid anhydride includes an unsaturated acid anhydride. Specifically, the unsaturated acid anhydride may include, but is not limited to, at least one of maleic anhydride and fumaric anhydride. In one embodiment of the present application, when the acid anhydride is an unsaturated acid anhydride, the unsaturated acid anhydride may be maleic anhydride, and maleic anhydride is used as a connecting structural unit monomer to form an unsaturated polyester.

[0080] In one embodiment of the present application, the acid anhydride further comprises a saturated acid anhydride. Specifically, the saturated acid anhydride may be, but is not limited to, phthalic anhydride. In one embodiment of the present application, when the acid anhydride is a saturated acid anhydride, the saturated acid anhydride is phthalic anhydride.

[0081] In one embodiment of the present application, the alcohol includes at least one of a polyol and a monohydric alcohol. Specifically, the polyol may include, but is not limited to, at least one of polyether polyols, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, 1,3-butylene glycol, butanediol, and neopentyl glycol; the monohydric alcohol may include, but is not limited to, at least one of benzyl alcohol, p-cresol, and cyclohexyl alcohol. In one embodiment of the present application, when the alcohol is a polyol, the polyol may be 1,2-propylene glycol. In another embodiment of the present application, when the alcohol is a monohydric alcohol, the monohydric alcohol may be used as an end-capping group of an unsaturated polyester, and the monohydric alcohol may be benzyl alcohol.

[0082] In one embodiment of the present application, the unsaturated polyester is formed by randomly connecting structural units derived from amide monomers, structural units derived from imide monomers, and connecting structural units. That is to say, the connection order can be structural units derived from amide monomers, structural units derived from imide monomers, and connecting structural units, or structural units derived from amide monomers, connecting structural units, and structural units derived from imide monomers, or connecting structural units, structural units derived from amide monomers, and structural units derived from imide monomers. In some embodiments, the unsaturated polyester can be a symmetrical structure. In other embodiments, the unsaturated polyester can be an asymmetrical structure, which can further improve the comprehensive performance of the unsaturated polyester.

[0083] In one embodiment of the present application, the end-capping group of the unsaturated polyester is derived from at least one of a monohydric alcohol and a monofunctional amide monomer. Specifically, the end-capping group may include but is not limited to In one embodiment of the present application, the end-capping group is In another embodiment of the present application, the end-capping group can be The positions of both are randomly distributed.

[0084] In one embodiment of the present application, in the unsaturated polyester, except for the end-capping group, the remaining structural units derived from the amide monomer, the structural units derived from the imide monomer and the connecting structural units are connected to form a repeating unit, and the repeating number n can be 1-10. Specifically, the repeating number can be but not limited to 1, 2, 4, 6, 8 or 10. In one embodiment of the present application, the repeating number can be 1-6. In another embodiment of the present application, the repeating number can be 5-10.

[0085] In one embodiment of the present application, the weight average molecular weight of the unsaturated polyester is 1000-5000. Suitable weight average molecular weight can improve the bonding ability and storage period of the resin. Specifically, the weight average molecular weight of the unsaturated polyester can be, but is not limited to, 1000, 1500, 1800, 2000, 3000, 4000, 4500 or 5000, etc. In one embodiment of the present application, the weight average molecular weight of the unsaturated polyester can be 1000-3000. In another embodiment of the present application, the weight average molecular weight of the unsaturated polyester can be 2000-5000.

[0086] The present application also provides a method for preparing an unsaturated polyester, comprising mixing an amide monomer and an imide monomer to obtain a mixed solution, and obtaining an unsaturated polyester after reaction. The preparation method provided by the present application is novel and has a simple preparation process. The obtained unsaturated polyester can improve the bonding ability and mechanical properties of the impregnation varnish, and improve the heat resistance and oil resistance of the impregnation varnish. The unsaturated polyester described in any of the above embodiments can be obtained by this method.

[0087] In one embodiment of the present application, the reaction temperature is 185°C-205°C, and the reaction time is 15h-25h. Appropriate reaction conditions can increase the synthesis rate of unsaturated polyester. Specifically, the reaction temperature can be, but not limited to, 185°C, 190°C, 195°C, 200°C or 205°C, etc.; the reaction time can be, but not limited to, 15h, 18h, 19h, 20h, 22h, 24h or 25h, etc. In one embodiment of the present application, the reaction temperature can be 185°C-200°C, and the reaction time can be 15h-22h. In another embodiment of the present application, the reaction temperature can be 195°C-205°C, and the reaction time can be 20h-25h.

[0088] In one embodiment of the present application, the reaction is carried out in a protective gas atmosphere, which is conducive to promoting the rapid progress of the reaction and improving the purity of the product. Specifically, the protective gas can be but is not limited to at least one of argon, nitrogen, helium and neon. In one embodiment of the present application, the protective gas can be nitrogen.

[0089] In one embodiment of the present application, the acid value of the mixed solution after the reaction is less than or equal to 25 mgKOH / g. Specifically, the acid value of the mixed solution after the reaction may be, but is not limited to, less than or equal to 25 mgKOH / g, less than or equal to 22 mgKOH / g, less than or equal to 20 mgKOH / g, less than or equal to 18 mgKOH / g, or less than or equal to 15 mgKOH / g, etc. In one embodiment of the present application, the acid value of the mixed solution after the reaction may be less than or equal to 22 mgKOH / g. In another embodiment of the present application, the acid value of the mixed solution after the reaction may be less than or equal to 20 mgKOH / g.

[0090] In one embodiment of the present application, the amide monomer may include but is not limited to

[0091] In one embodiment of the present application, the amide monomer can be In another embodiment of the present application, the amide monomer may include

[0092]

[0093] In one embodiment of the present application, the preparation of the amide monomer includes subjecting a dibasic acid chloride and a hydroxyl-containing monoamine to a first reaction to obtain an amide monomer. Specifically, the dibasic acid chloride may include, but is not limited to, at least one of adipoyl chloride, succinoyl chloride, terephthaloyl chloride, and isophthaloyl chloride; the hydroxyl-containing monoamine may include, but is not limited to, at least one of isopropanolamine, 3-amino-1-propanol, and monoethanolamine. In one embodiment of the present application, the dibasic acid chloride may be succinoyl chloride, and the hydroxyl-containing monoalcohol may be 3-amino-1-propanol. In another embodiment of the present application, the dibasic acid chloride may be terephthaloyl chloride, and the hydroxyl-containing monoalcohol may be isopropanolamine. In some embodiments, the molar ratio of the dibasic acid chloride to the hydroxyl-containing monoamine is 1:2.

[0094] In one embodiment of the present application, the temperature of the first reaction is 0°C-25°C. Specifically, the temperature of the first reaction may be, but is not limited to, 0°C, 5°C, 10°C, 15°C, 20°C or 25°C. In one embodiment of the present application, the temperature of the first reaction may be 0°C-15°C. In another embodiment of the present application, the temperature of the first reaction may be 10°C-25°C. In some embodiments, the first reaction time is 5h, wherein the reaction is performed at 0°C for 2h and at 25°C for 3h.

[0095] In another embodiment of the present application, the preparation of the amide monomer includes subjecting a dibasic acid and a hydroxyl-containing monoamine to a second reaction to obtain an amide monomer. Specifically, the dibasic acid may be, but is not limited to, at least one of succinic acid, adipic acid, terephthalic acid, and isophthalic acid; the hydroxyl-containing monoamine may be, but is not limited to, at least one of isopropanolamine, 3-amino-1-propanol, and monoethanolamine. In one embodiment of the present application, the dibasic acid may be succinic acid, and the hydroxyl-containing monoalcohol may be 3-amino-1-propanol. In another embodiment of the present application, the dibasic acid may be adipic acid, and the hydroxyl-containing monoalcohol may be isopropanolamine, and the reaction formula is shown in Formula (I):

[0096]

[0097] In some embodiments, the molar ratio of the dibasic acid to the hydroxyl-containing monoamine is 1:2.

[0098] In one embodiment of the present application, the second reaction includes a first sub-stage and a second sub-stage, the reaction temperature of the first sub-stage is 140°C-160°C, and the reaction temperature of the second sub-stage is 200°C-250°C. Specifically, the reaction temperature of the first sub-stage may be, but is not limited to, 140°C, 142°C, 148°C, 150°C, 155°C, 158°C or 160°C, etc.; the reaction temperature of the second sub-stage may be, but is not limited to, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C, etc. In one embodiment of the present application, the reaction temperature of the first sub-stage is 140°C-150°C, and the reaction temperature of the second sub-stage is 200°C-230°C. In another embodiment of the present application, the reaction temperature of the first sub-stage is 150°C-160°C, and the reaction temperature of the second sub-stage is 225°C-250°C. In some embodiments, the reaction time of the first sub-stage is 5 hours; the reaction time of the second sub-stage is 6 hours, including 3 hours at 200° C. and 3 hours at 220° C.

[0099] In another embodiment of the present application, the preparation of the amide monomer includes subjecting the diamine and the hydroxyl-containing acid to a third reaction to obtain the amide monomer. Specifically, the diamine may be, but is not limited to, at least one of diamine, hexamethylenediamine, isophoronediamine, p-phenylenediamine, m-phenylenediamine, 4,4-diaminodiphenylmethane, and 4,4-diaminodiphenyl ether; the hydroxyl-containing acid includes a hydroxyl-containing monoacid, and the hydroxyl-containing monoacid may be, but is not limited to, at least one of 3-hydroxypropionic acid, 2-hydroxypropionic acid, hydroxybenzoic acid, hydroxyphenylacetic acid, and hydroxyphenoxyacetic acid. In one embodiment of the present application, the diamine may be diamine, and the hydroxyl-containing acid may be 3-hydroxypropionic acid. In some embodiments, the molar ratio of the diamine to the hydroxyl-containing acid is 1:2.

[0100] In one embodiment of the present application, the third reaction includes a third sub-stage and a fourth sub-stage, the reaction temperature of the third sub-stage is 140°C-160°C, and the reaction temperature of the fourth sub-stage is 200°C-250°C. Specifically, the reaction temperature of the third sub-stage may be, but is not limited to, 140°C, 142°C, 148°C, 150°C, 155°C, 158°C or 160°C, etc.; the reaction temperature of the fourth sub-stage may be, but is not limited to, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C, etc. In one embodiment of the present application, the reaction temperature of the third sub-stage is 140°C-150°C, and the reaction temperature of the fourth sub-stage is 200°C-230°C. In another embodiment of the present application, the reaction temperature of the third sub-stage is 150°C-160°C, and the reaction temperature of the fourth sub-stage is 225°C-250°C.

[0101] In one embodiment of the present application, the imide monomer may include but is not limited to

[0102]

[0103] In one embodiment of the present application, the imide monomer may be In another embodiment of the present application, the imide monomer may include

[0104]

[0105] In one embodiment of the present application, when preparing the amide monomer, it also includes adding a first solvent to the reaction system to facilitate better reaction. The first solvent may include but is not limited to at least one of N, N-dimethylformamide (DMF) and N-methylpyrrolidone (NMP). In one embodiment of the present application, the first solvent may be N-methylpyrrolidone (NMP). In some embodiments, after preparing the amide monomer, it also includes adding a purification solvent to the reaction system for purification, and the purification solvent may be at least one of ethyl acetate and a mixed solution of ethanol and water.

[0106] In one embodiment of the present application, the preparation of the imide monomer includes: subjecting the acid anhydride and the amino compound to a fourth reaction to obtain the imide monomer. Specifically, the acid anhydride may include but is not limited to at least one of tetrahydrophthalic anhydride, phthalic anhydride, methylhexahydrophthalic anhydride, 1,2,4-cyclohexanetricarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride and diphenyl ether tetracarboxylic dianhydride; the amino compound may include but is not limited to at least one of monoethanolamine, 1,2-propylenediamine, isopropanolamine, 2,2-oxybisethylamine, 4,4'-diaminodiphenyl ether, isophoronediamine, aminopropionic acid, propylenediamine, hexamethylenediamine and meta-phenylenediamine. In one embodiment of the present application, the acid anhydride may be at least one of tetrahydrophthalic anhydride, phthalic anhydride and methylhexahydrophthalic anhydride, and the imide monomer is a capping group. In some embodiments, the acid anhydride may be tetrahydrophthalic anhydride, the amino compound may be monoethanolamine, and the reaction formula is shown in formula (II):

[0107] In another embodiment of the present application, the acid anhydride may be at least one of 1,2,4-cyclohexanetricarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride and diphenyl ether tetracarboxylic dianhydride.

[0108] In one embodiment of the present application, the fourth reaction includes a fifth sub-stage and a sixth sub-stage, the reaction temperature of the fifth sub-stage is 100°C-130°C, and the reaction temperature of the sixth sub-stage is 150°C-180°C. Specifically, the reaction temperature of the sixth sub-stage may be, but is not limited to, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C or 180°C, etc. In one embodiment of the present application, the reaction temperature of the fifth sub-stage may be 100°C-120°C, and the reaction temperature of the sixth sub-stage may be 150°C-170°C. In another embodiment of the present application, the reaction temperature of the fifth sub-stage may be 110°C-130°C, and the reaction temperature of the sixth sub-stage may be 165°C-180°C. In some embodiments, the reaction time of the fifth sub-stage may be 3h; the reaction time of the sixth sub-stage is 4h, wherein 150°C is reacted for 2h and 180°C is reacted for 2h.

[0109] In one embodiment of the present application, when preparing the imide monomer, it also includes adding a second solvent to the reaction system to promote the rapid reaction. The second solvent may include, but is not limited to, at least one of N, N-dimethylformamide (DMF) and N-methylpyrrolidone (NMP). In one embodiment of the present application, the second solvent may be N-methylpyrrolidone (NMP). In some embodiments, after preparing the imide monomer, it also includes adding a purification solvent to the reaction system, and the purification solvent may be at least one of ethyl acetate and ethanol.

[0110] In one embodiment of the present application, the method for preparing unsaturated polyester further comprises mixing the connecting structural unit monomer with the amide monomer and the imide monomer to obtain a mixed solution. The connecting structural unit monomer comprises an alcohol, and at least one of an anhydride and an acid.

[0111] In one embodiment of the present application, the acid includes an unsaturated acid. Specifically, the unsaturated acid may include, but is not limited to, at least one of maleic acid and fumaric acid. In one embodiment of the present application, when the acid is an unsaturated acid, the unsaturated acid may be maleic acid, and maleic acid is used as a connecting structural unit monomer to form an unsaturated polyester.

[0112] In one embodiment of the present application, the acid further comprises a saturated acid. Specifically, the saturated acid may include, but is not limited to, at least one of terephthalic acid, isophthalic acid, adipic acid and succinic acid. In one embodiment of the present application, when the acid is a saturated acid, the saturated acid may be succinic acid.

[0113] In one embodiment of the present application, the acid anhydride includes an unsaturated acid anhydride. Specifically, the unsaturated acid anhydride may include, but is not limited to, at least one of maleic anhydride and fumaric anhydride. In one embodiment of the present application, when the acid anhydride is an unsaturated acid anhydride, the unsaturated acid anhydride may be maleic anhydride, and maleic anhydride is used as a connecting structural unit monomer to form an unsaturated polyester.

[0114] In one embodiment of the present application, the acid anhydride further comprises a saturated acid anhydride. Specifically, the saturated acid anhydride may be, but is not limited to, phthalic anhydride. In one embodiment of the present application, when the acid anhydride is a saturated acid anhydride, the saturated acid anhydride is phthalic anhydride.

[0115] In one embodiment of the present application, the alcohol includes at least one of a polyol and a monohydric alcohol. Specifically, the polyol may include, but is not limited to, at least one of polyether polyols, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, 1,3-butylene glycol, butanediol, and neopentyl glycol; the monohydric alcohol may include, but is not limited to, at least one of benzyl alcohol, p-cresol, and cyclohexyl alcohol. In one embodiment of the present application, when the alcohol is a polyol, the polyol may be 1,2-propylene glycol. In another embodiment of the present application, when the alcohol is a monohydric alcohol, the monohydric alcohol may be used as an end-capping group of an unsaturated polyester, and the monohydric alcohol may be benzyl alcohol.

[0116] In one embodiment of the present application, in the mixed solution, the weight proportion of the amide monomer is 3-9 parts, and an appropriate amount of the amide monomer can improve the bonding ability and mechanical properties of the dipping paint. Specifically, the weight proportion of the amide monomer can be, but is not limited to, 3, 4, 5, 6, 7, 8 or 9 parts. In one embodiment of the present application, the weight proportion of the amide monomer can be 3-7 parts. In another embodiment of the present application, the weight proportion of the amide monomer can be 5-9 parts.

[0117] In one embodiment of the present application, in the mixed solution, the weight parts of the imide monomer are 13 parts to 20 parts, and an appropriate amount of the imide monomer can improve the heat resistance and oil resistance of the dipping varnish. Specifically, the weight parts of the imide monomer can be, but are not limited to, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, etc. In one embodiment of the present application, the weight parts of the imide monomer can be 13 parts to 18 parts. In another embodiment of the present application, the weight parts of the imide monomer can be 16 parts to 20 parts.

[0118] In one embodiment of the present application, in the mixed solution, the weight parts of the connecting structure unit monomers are 18 parts to 71 parts. Specifically, the weight parts of the connecting structure unit monomers can be, but are not limited to, 18 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 68 parts or 71 parts. In one embodiment of the present application, the weight parts of the connecting structure unit monomers can be 18 parts to 50 parts. In another embodiment of the present application, the weight parts of the connecting structure unit monomers can be 45 parts to 71 parts.

[0119] The present application also provides the use of unsaturated polyester in the fields of plastics, artificial stones, fibers or paints, which can improve the bonding ability, mechanical properties, heat resistance and / or oil resistance of plastics, artificial stones, fibers or paints.

[0120] The present application also provides an impregnation varnish, which includes the unsaturated polyester described in any one of the above embodiments, thereby improving the bonding ability, mechanical strength, oil resistance and heat resistance of the unsaturated polyester.

[0121] In one embodiment of the present application, the impregnation varnish further comprises a reactive diluent, an initiator and an inhibitor. The reactive diluent can reduce the viscosity of the impregnation varnish and improve the coating ability of the impregnation varnish; the initiator can promote the curing reaction of the impregnation varnish and increase the curing rate of the impregnation varnish; the inhibitor can prevent large-scale agglomeration in the impregnation varnish and increase the storage time of the impregnation varnish.

[0122] In one embodiment of the present application, in the dipping varnish, the weight proportion of the unsaturated polyester is 40-70 parts. Specifically, the weight proportion of the unsaturated polyester may be, but is not limited to, 40, 45, 50, 55, 60, 65 or 70 parts. In one embodiment of the present application, in the dipping varnish, the weight proportion of the unsaturated polyester may be 40-55 parts. In another embodiment of the present application, in the dipping varnish, the weight proportion of the unsaturated polyester may be 50-70 parts.

[0123] In one embodiment of the present application, the active diluent can reduce the viscosity of the impregnating varnish, improve the coating ability of the impregnating varnish, and help improve the use effect of the impregnating varnish. Specifically, the active diluent can include but is not limited to at least one of vinyl toluene, isooctyl methacrylate, lauryl methacrylate, diallyl phthalate, divinyl toluene, triethylene glycol dimethacrylate and 1,6-hexanedioic acid diacrylate. In one embodiment of the present application, the active diluent can be divinyl toluene. In another embodiment of the present application, the active diluent can be vinyl toluene.

[0124] In one embodiment of the present application, in the impregnation varnish, the weight proportion of the active diluent is 30-60 parts, and an appropriate amount of active diluent can improve the coating ability of the impregnation varnish. Specifically, the weight proportion of the active diluent can be, but is not limited to, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or 60 parts. In one embodiment of the present application, in the impregnation varnish, the weight proportion of the active diluent can be 30-50 parts. In another embodiment of the present application, in the impregnation varnish, the weight proportion of the active diluent can be 45-60 parts.

[0125] In one embodiment of the present application, the initiator can promote the curing reaction of the impregnating varnish and increase the curing rate of the impregnating varnish. Specifically, the initiator can include but is not limited to at least one of diisopropyl hydroperoxide, diisopropyl peroxydicarbonate, azobisisobutyronitrile, diisopropyl peroxide, benzoyl peroxide and tert-butyl perbenzoate. In one embodiment of the present application, the initiator can be diisopropyl hydroperoxide. In another embodiment of the present application, the initiator can be benzoyl peroxide.

[0126] In one embodiment of the present application, the weight portion of the initiator in the dipping varnish is 0.5-5 parts, and an appropriate amount of initiator can promote the curing reaction of the dipping varnish. Specifically, the weight portion of the initiator can be, but is not limited to, 0.5, 1, 2, 3, 4 or 5 parts. In one embodiment of the present application, the weight portion of the initiator in the dipping varnish can be 0.5-3 parts. In another embodiment of the present application, the weight portion of the initiator in the dipping varnish can be 2.5-5 parts.

[0127] In one embodiment of the present application, the inhibitor can prevent large-scale agglomeration in the dipping varnish and increase the storage time of the dipping varnish. Specifically, the inhibitor can include but is not limited to at least one of methyl hydroquinone, p-hydroxyanisole, 2-tert-butylhydroquinone, tert-butylcatechol, hydroquinone, benzoquinone and 2,5-di-tert-butylhydroquinone. In one embodiment of the present application, the inhibitor can be hydroquinone. In another embodiment of the present application, the inhibitor can be p-hydroxyanisole.

[0128] In one embodiment of the present application, in the dipping varnish, the weight portion of the polymerization inhibitor is 0.01-0.1 parts, and an appropriate amount of polymerization inhibitor can improve the storage capacity of the dipping varnish. Specifically, the weight portion of the polymerization inhibitor can be, but is not limited to, 0.01 parts, 0.02 parts, 0.04 parts, 0.06 parts, 0.08 parts or 0.1 parts, etc. In one embodiment of the present application, in the dipping varnish, the weight portion of the polymerization inhibitor can be 0.01-0.08 parts. In another embodiment of the present application, in the dipping varnish, the weight portion of the polymerization inhibitor can be 0.05-0.1 parts.

[0129] In one embodiment of the present application, defoamers, leveling agents, pigments, flame retardants, light stabilizers, etc. may be added to the impregnating varnish to improve the comprehensive performance of the impregnating varnish and meet different industrial needs.

[0130] In one embodiment of the present application, the preparation method of the impregnation varnish includes: mixing unsaturated polyester, reactive diluent, inhibitor and initiator to obtain impregnation varnish. Specific process: at the first mixing temperature, add unsaturated polyester, reactive diluent and inhibitor and stir for 2h, cool to the second mixing temperature, add initiator and stir for 2h to obtain impregnation varnish. The first mixing temperature is 80℃-100℃, and the second mixing temperature is less than or equal to 40℃. Specifically, the first mixing temperature may be but not limited to 80℃, 82℃, 86℃, 90℃, 94℃, 98℃ or 100℃, etc.; the second mixing temperature may be but not limited to less than or equal to 40℃, less than or equal to 38℃, less than or equal to 35℃, less than or equal to 32℃ or less than or equal to 30℃, etc. In one embodiment of the present application, the first mixing temperature may be 80℃-95℃, and the second mixing temperature may be less than or equal to 40℃. In another embodiment of the present application, the first mixing temperature may be 90℃-100℃, and the second mixing temperature may be less than or equal to 35℃.

[0131] The present application provides a motor, the motor comprising a motor stator winding and a paint layer provided on the motor stator winding, the paint layer being formed by the impregnation varnish described in any one of the above-mentioned embodiments. The motor provided by the present application has good mechanical properties, strong bonding ability, excellent heat resistance and oil resistance, improves the insulation performance, heat resistance and mechanical strength of the motor, and is conducive to extending the service life of the motor. In one embodiment of the present application, the paint layer can be provided by dripping, dipping, spraying or coating. In one embodiment of the present application, the paint layer is formed on the motor stator winding by dripping the impregnation varnish on the motor stator winding or dipping the motor stator winding in the impregnation varnish, and curing.

[0132] The present application provides a vehicle, which includes a motor provided by any one of the above-mentioned embodiments. The motor has good insulation performance, good heat resistance, high mechanical strength, and a long service life, which is beneficial to improving the safety performance and service life of the vehicle.

[0133] The effect of the technical solution of the present application is further illustrated below through specific examples.

[0134] Example 1

[0135] Preparation of amide monomer: 0.5 mol of succinic acid was placed in a three-necked flask, and 100 ml of NMP was added to stir and mix to dissolve, then 1 mol of isopropanolamine was added, the temperature was raised to 150°C and stirred to react for 5 h, 200°C for 3 h, and 220°C for 3 h, 1000 ml of ethyl acetate was added to precipitate, filtered, washed and dried to obtain amide monomer, the structural formula of amide monomer is

[0136]

[0137] Preparation of imide monomer: 1 mol of tetrahydrophthalic anhydride is placed in a three-necked flask, heated to 110°C and stirred to dissolve, 1 mol of monoethanolamine is added dropwise after the tetrahydrophthalic anhydride is dissolved, and after the addition is complete, the temperature is raised to 150°C and stirred to react for 2 hours, and then at 180°C for 3 hours to obtain the imide monomer. The structural formula of the imide monomer is:

[0138] 4 parts of amide monomer, 16 parts of imide monomer, 14 parts of maleic anhydride, 4 parts of phthalic anhydride, 6 parts of adipic acid, 4 parts of 1,2-propylene glycol, and 12 parts of neopentyl glycol were added in sequence, and the temperature was gradually raised to 195°C. The mixture was reacted under nitrogen for 20 hours, and the acid value was reduced to below 25 mgKOH / g to obtain an unsaturated polyester having a weight average molecular weight of 2500. The reaction formula is shown in formula (III):

[0139]

[0140] The temperature was cooled to 90°C, 0.025 parts of inhibitor (hydroquinone) and 40 parts of diluent (5 parts of vinyl toluene and 35 parts of 1,6-hexanedioic acid diacrylate) were added, and the mixture was stirred at 80°C for 2 hours. The mixture was cooled to below 40°C, 3.5 parts of initiator (diisopropylbenzene peroxide) were added, and the mixture was stirred for 2 hours to obtain the impregnation varnish.

[0141] Example 2

[0142] The difference from Example 1 is that 7 parts of amide monomer and 9 parts of neopentyl glycol are added.

[0143] Example 3

[0144] The difference from Example 1 is that 11 parts of amide monomer, 8 parts of neopentyl glycol, 2 parts of phthalic anhydride, and 3 parts of 1,2-propylene glycol are added.

[0145] Example 4

[0146] The difference from Example 1 is that the amide monomer structural formula is The preparation method of the amide monomer is as follows: 0.5 mol of isophthaloyl chloride is placed in a three-necked flask, and 160 ml of DMF is added to stir and mix to dissolve, and then a DMF solution containing 1 mol of monoethanolamine (concentration 1 mol / 60 ml) is added dropwise, and the mixture is stirred and reacted at a temperature of about 0°C for 2 hours, and then reacted at room temperature for 3 hours, and 1000 ml of ethyl acetate is added to precipitate, and the mixture is filtered, washed, and dried to obtain the amide monomer.

[0147] Example 5

[0148] The difference from Example 1 is that the imide monomer structural formula is The preparation method of imide is as follows: 1 mol of trimellitic anhydride is placed in a three-necked flask, and 160 ml of NMP is added to stir, mix and dissolve, the temperature is raised to 110° C., and then 0.5 mol of 1,2-propylenediamine is added dropwise, the temperature is raised to 110° C. and stirred for reaction for 3 hours, the temperature is raised to 150° C. and stirred for reaction for 2 hours, the temperature is raised to 180° C. and stirred for reaction for 2 hours, 1000 ml of ethyl acetate is added for precipitation, and the imide monomer is obtained by filtering, washing and drying; 16 parts of imide monomer, 12 parts of maleic anhydride, 4 parts of adipic acid, 4 parts of 1,2-propylene glycol, 9 parts of neopentyl glycol, and 9 parts of benzyl alcohol are added to obtain unsaturated polyester; 42 parts of diluent (6 parts of vinyl toluene and 36 parts of 1,6-hexanedioic acid diacrylate) are added.

[0149] Example 6

[0150] The difference from Example 1 is that the imide monomer structural formula is Add 22 parts of imide monomer, 11 parts of maleic anhydride, 3 parts of adipic acid, 3 parts of 1,2-propylene glycol, 7 parts of neopentyl glycol, 9 parts of benzyl alcohol, excluding phthalic anhydride; 42 parts of diluent (6 parts of vinyl toluene and 36 parts of 1,6-adipic acid diacrylate).

[0151] Example 7

[0152] The difference from Example 1 is that the amide monomer structural formula is The structural formula of imide monomer is 12 parts of maleic anhydride, 4 parts of adipic acid, 8 parts of neopentyl glycol, 9 parts of benzyl alcohol, phthalic anhydride not included; 43 parts of diluent (6 parts of vinyl toluene and 37 parts of 1,6-adipic acid diacrylate) were added.

[0153] Comparative Example 1

[0154] The difference from Example 1 is that the imide monomer is not included, and 4 parts of amide monomer, 15 parts of maleic anhydride, 7 parts of phthalic anhydride, 6 parts of adipic acid, 7 parts of 1,2-propylene glycol, 12 parts of neopentyl glycol, and 9 parts of benzyl alcohol are added.

[0155] Comparative Example 2

[0156] The difference from Example 1 is that amide monomer is not included, and 16 parts of imide monomer, 15 parts of maleic anhydride, 4 parts of phthalic anhydride, 8 parts of adipic acid, 5 parts of 1,2-propylene glycol, and 15 parts of neopentyl glycol are added.

[0157] Comparative Example 3

[0158] The difference from Example 1 is that imide monomer and amide monomer are not included, and 15 parts of maleic anhydride, 7 parts of phthalic anhydride, 9 parts of adipic acid, 6 parts of 1,2-propylene glycol, 16 parts of neopentyl glycol, 9 parts of benzyl alcohol; 35 parts of diluent (4 parts of vinyl toluene and 31 parts of 1,6-hexanedioic acid diacrylate) are added.

[0159] Performance Testing

[0160] The dipping varnishes prepared in the above Examples 1-7 and Comparative Examples 1-3 were subjected to viscosity tests at room temperature (25° C.) according to GB / T 15022.2-2017 and GB / T24148.4-2009. The test results are shown in Table 1.

[0161] The impregnating varnishes prepared in the above Examples 1-7 and Comparative Examples 1-3 were subjected to a solid volatile matter test according to GB / T 15022.2-2017. The test process was: maintained at 150° C. for 1 hour. The test results of the volatile matter mass fraction are shown in Table 1.

[0162] The impregnating varnishes prepared in the above Examples 1-7 and Comparative Examples 1-3 were subjected to a bonding strength test at room temperature (25° C.) according to the twisted coil method: Method A in GB / T11028-1999. The test results are shown in Table 1.

[0163] The dipping varnishes prepared in the above Examples 1-7 and Comparative Examples 1-3 were subjected to a tensile strength test at room temperature (25° C.) according to GB / T 2567-2008. The test results are shown in Table 1.

[0164] The impregnating varnishes prepared in the above-mentioned Examples 1-7 and Comparative Examples 1-3 were subjected to a thermal gravimetric analysis (TGA) test according to GB / T 13464-2008 to obtain a TGA curve, wherein the testing process comprises: grinding the cured impregnating varnish into powder, filtering through a 100-mesh filter, drying at 210°C for 16h, taking 8±2mg of the sample, heating to 600°C at 50°C / min in an oxygen atmosphere, and testing the temperature at which the weight loss reaches 10wt%. The test results are shown in Table 1.

[0165] The impregnating varnishes obtained in the above Examples 1-7 and Comparative Examples 1-3 were prepared into twisted coils and stretched strips according to the twisted coil method: Method A in GB / T 11028-1999 and GB / T 2567-2008, respectively, and the following oil resistance test was carried out:

[0166] a. High temperature oil resistant treatment conditions and test items: The samples were immersed in gear oil with 0.5% water added and kept at 150°C for 700 hours. After 700 hours, the samples were taken out for bonding strength and tensile strength tests. The test results are shown in Table 2.

[0167] b. Hot and cold shock treatment conditions and test items: The samples were immersed in gear oil with 0.5% water added, maintained at 155°C for 40 hours, -40°C for 8 hours, 48 ​​hours per cycle, a total of 8 cycles, the sample switching time was <30s, and after 8 cycles of hot and cold shock (384h), the samples were taken out for bonding strength and tensile strength tests. The test results are shown in Table 2.

[0168] The impregnating varnishes prepared in Example 1 and Comparative Examples 1-3 were subjected to infrared spectroscopy test according to GB / T 6040-2019. The test results are as follows: Figures 1 to 4 shown. Figure 1 This is an infrared spectrum test chart of the dipping varnish provided in Example 1 of the present application; Figure 2 This is an infrared spectrum test chart of the dipping paint provided in Comparative Example 1 of the present application; Figure 3 This is an infrared spectrum test chart of the dipping paint provided in Comparative Example 2 of the present application; Figure 4 This is the infrared spectrum test diagram of the impregnation paint provided in Comparative Example 3 of the present application. It can be seen that in Comparative Example 1, only amide monomer is added, and at 3354.86 cm -1 、3223.53cm -1 and 1665.47cm -1 The characteristic peak of amide appeared at 1398.45 cm -1 and 1121.86cm -1 The characteristic peak of imide appeared at 1715.58 cm-1. In comparative example 3, no amide monomer and imide monomer were added, and only the peak at 1715.58 cm-1 was observed. -1 and 1152.07cm -1 The characteristic peak of ester group appeared at the position, but there was no characteristic peak of amide and imide. After adding amide monomer and imide monomer in Example 1, the peak at 3371.27 cm -1 、3225.17cm -1 、1664.27cm -1 、1398.97cm -1 and 1121.04cm -1 The amide and imide characteristic peaks appearing at the positions indicate that the present application simultaneously introduces amide monomers and imide monomers into the unsaturated polyester. Figure 5From the thermogravimetric analysis diagrams of the impregnating varnishes provided in Example 1, Example 7 and Comparative Examples 1-3 of the present application after curing, it can be seen that the impregnating varnishes provided in the examples of the present application are not easy to volatilize and have good heat resistance.

[0169] Table 1 Performance test results

[0170]

[0171] Table 2 High temperature oil resistance and hot and cold shock oil resistance performance test results

[0172]

[0173] It can be seen from Examples 1-7 and Comparative Examples 1-3 that the addition of amide monomers and imide monomers to unsaturated polyesters can improve the mechanical strength, bonding ability, heat resistance and oil resistance of the dipping varnish, and the comprehensive performance is excellent. It can be seen from Examples 1-3 and 5-6 that the appropriate content of amide monomers and imide monomers can improve the coating ability of the dipping varnish, maintain a suitable viscosity, prevent agglomeration, and help improve the bonding ability and tensile strength of the dipping varnish. It can be seen from Examples 1 and 7 that the addition of imide monomers can improve the heat resistance of unsaturated polyesters. In the added imide monomers, the more benzene ring structures, the better the heat resistance of the unsaturated polyester. It can be seen from Example 1 and Comparative Example 1 that imide monomers can improve the tensile strength, heat resistance and oil resistance of the dipping varnish. It can be seen from Example 1 and Comparative Example 2 that amide monomers can improve the bonding ability and tensile strength of the dipping varnish. The unsaturated polyester provided by the present application has excellent bonding force, mechanical strength, heat resistance and oil resistance, and can promote the wide application of unsaturated polyesters.

[0174] The above is a preferred embodiment of the present application, but it should not be understood as limiting the scope of the present application. It should be noted that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application, and these improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. An unsaturated polyester, characterized in that The unsaturated polyester includes a structural unit derived from an amide monomer and a structural unit derived from an imide monomer.

2. The unsaturated polyester according to claim 1, characterized in that The structural unit derived from the amide monomer includes At least one of, R1, R2 and R3 are independently selected from a substituted or unsubstituted divalent alkyl group, a substituted or unsubstituted divalent aromatic group, or a substituted or unsubstituted divalent alicyclic group.

3. The unsaturated polyester according to claim 1, characterized in that The structural unit derived from the imide monomer includes At least one of the following, where R 1 , R 2 , R 4 , R 6 and R 8 are independently selected from substituted or unsubstituted divalent alkyl groups, substituted or unsubstituted divalent aromatic groups, or substituted or unsubstituted divalent alicyclic groups, R 3 and R 5 are independently selected from substituted or unsubstituted trivalent alkyl, substituted or unsubstituted trivalent aryl, or substituted or unsubstituted trivalent alicyclic group, R 7 is selected from a carbon atom, a substituted or unsubstituted tetravalent aromatic group, or a substituted or unsubstituted tetravalent alicyclic group.

4. The unsaturated polyester according to claim 2 or 3, characterized in that The substituents in the substituted or unsubstituted divalent alkyl group, the substituted or unsubstituted divalent aromatic group, the substituted or unsubstituted divalent alicyclic group, the substituted or unsubstituted trivalent alkyl group, the substituted or unsubstituted trivalent aromatic group, the substituted or unsubstituted trivalent alicyclic group, the substituted or unsubstituted tetravalent aromatic group, and the substituted or unsubstituted tetravalent alicyclic group include at least one of a halogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a hydroxyl group, a nitro group, an amine group, a thiol group, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted aryloxy group.

5. The unsaturated polyester according to claim 1, characterized in that The weight proportion of the structural unit derived from the amide monomer is 3 to 9 parts, and the weight proportion of the structural unit derived from the imide monomer is 13 to 20 parts.

6. The unsaturated polyester according to claim 1, characterized in that The unsaturated polyester further comprises a linking structural unit, wherein the linking structural unit comprises a linking structural unit monomer derived from an alcohol and at least one linking structural unit monomer derived from an anhydride and an acid; The weight proportion of the connecting structural unit is 18 to 71 parts.

7. The unsaturated polyester according to claim 6, characterized in that The acid comprises an unsaturated acid, and the unsaturated acid comprises at least one of maleic acid and fumaric acid; The acid anhydride includes an unsaturated acid anhydride, and the unsaturated acid anhydride includes at least one of maleic anhydride and fumaric anhydride; The alcohol includes at least one of a polyol and a monool, the polyol includes at least one of polyether polyol, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, 1,3-butylene glycol, butanediol and neopentyl glycol, and the monool includes at least one of benzyl alcohol, p-cresol and cyclohexyl alcohol.

8. The unsaturated polyester according to claim 1, characterized in that The weight average molecular weight of the unsaturated polyester is 1000-5000.

9. A method for preparing an unsaturated polyester according to any one of claims 1 to 8, characterized in that: include: The amide monomer and the imide monomer are mixed to obtain a mixed solution, and unsaturated polyester is obtained after reaction.

10. The preparation method according to claim 9, characterized in that: The amide monomers include At least one of, R1, R2 and R3 are independently selected from a substituted or unsubstituted divalent alkyl group, a substituted or unsubstituted divalent aromatic group, or a substituted or unsubstituted divalent alicyclic group.

11. The preparation method according to claim 9, characterized in that: The imide monomer includes At least one of R 1 , R 2 , R 4 , R 6 and R 8 are independently selected from substituted or unsubstituted divalent alkyl groups, substituted or unsubstituted divalent aromatic groups, or substituted or unsubstituted divalent alicyclic groups, R 3 and R 5 are independently selected from substituted or unsubstituted trivalent alkyl, substituted or unsubstituted trivalent aryl, or substituted or unsubstituted trivalent alicyclic group, R 7 is selected from a carbon atom, a substituted or unsubstituted tetravalent aromatic group, or a substituted or unsubstituted tetravalent alicyclic group.

12. The preparation method according to claim 9, characterized in that: The reaction temperature is 185°C-205°C, and the reaction time is 15h-25h.

13. The preparation method according to claim 9, characterized in that: Also includes: The connecting structure unit monomer is mixed with the amide monomer and the imide monomer to obtain the mixed solution; the connecting structure unit monomer includes alcohol, and at least one of anhydride and acid.

14. The preparation method according to claim 13, characterized in that: In the mixed solution, the weight proportion of the amide monomer is 3 to 9 parts, and the weight proportion of the imide monomer is 13 to 20 parts; The weight proportion of the connecting structure unit monomer is 18 parts to 71 parts.

15. Use of the unsaturated polyester according to any one of claims 1 to 8 or the unsaturated polyester prepared by the preparation method according to any one of claims 9 to 14 in the fields of plastics, artificial stones, fibers or paints.

16. A dipping varnish, characterized in that The impregnating varnish comprises the unsaturated polyester described in any one of claims 1 to 8 or the unsaturated polyester prepared by the preparation method described in any one of claims 9 to 14.

17. The impregnation varnish according to claim 16, characterized in that The impregnation varnish further comprises one or more of a reactive diluent, an initiator and an inhibitor.

18. The impregnation varnish according to claim 17, characterized in that In the impregnating varnish, the weight portion of the unsaturated polyester is 40-70 parts; the weight portion of the active diluent is 30-60 parts; the weight portion of the initiator is 0.5-5 parts; and the weight portion of the inhibitor is 0.01-0.1 parts.

19. A motor, characterized in that: The motor comprises a motor stator winding and a paint layer arranged on the motor stator winding, and the paint layer is formed by the impregnation paint according to any one of claims 16-18.

20. A vehicle, characterized in that: The vehicle comprises the electric machine of claim 19.

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