Prepreg material of polyurethane modified epoxy resin and preparation method thereof

Abstract

The invention provides a polyurethane modified epoxy resin material for a prepreg and a preparation method of the polyurethane modified epoxy resin material. Comprising 10-35 parts by weight of polyester or polyether polyol, 1-10 parts by weight of isocyanate, 40-70 parts by weight of epoxy resin, 1-3 parts by weight of a light stabilizer, 1-2 parts by weight of an antioxidant, 1-2 parts by weight of an ultraviolet absorbent and 5-30 parts by weight of a chain extender and a curing agent. According to the invention, the intrinsic flexible epoxy resin is prepared by grafting modification of the polyurethane prepolymer, and is applied to a prepreg resin system and a medium-temperature cured carbon fiber prepreg, so that the brittleness of the epoxy resin is improved, and the elongation at break of the epoxy resin is improved, thereby realizing a toughening effect and a composite material forming process.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane elastomers, and relates to a polyurethane modified epoxy resin material for prepreg and a preparation method and application thereof, and in particular to a polyurethane modified epoxy resin prepreg material and a preparation method thereof. Background Art

[0002] At present, fiber-reinforced epoxy-based composite materials are increasingly used in aerospace, automotive, construction and other fields. Epoxy resin, as the most commonly used medium-temperature curing prepreg resin matrix, must have good fracture toughness so that the fibers in the prepreg can effectively transfer stress. At the same time, it is necessary to adjust the bonding properties of the prepreg by controlling the viscosity of the matrix resin and reduce the resin fluidity of the prepreg to meet the requirements of the composite material molding process.

[0003] Prepreg is a composite material obtained by impregnating continuous fibers or fabrics with resin. Usually, the resin body is an intermediate of the composite material. However, due to the high crosslinking density of epoxy resin cured products, it is highly brittle, and the fiber-reinforced epoxy-based composites prepared from it have low toughness. The toughness between the fiber and the resin matrix cannot achieve a matching effect, and the high performance of the fiber cannot be better exerted.

[0004] Therefore, how to find a more suitable epoxy resin material for prepreg to solve the above-mentioned problems existing in the prior art has become one of the focuses of widespread attention of many researchers in the industry. Summary of the invention

[0005] In view of this, the technical problem solved by the present invention is to provide a polyurethane modified epoxy resin material for prepreg and its preparation method and application, in particular a polyurethane modified epoxy resin prepreg material. The present invention provides an intrinsic flexible epoxy resin prepared by grafting and modifying a polyurethane prepolymer, which is applied to a prepreg resin system and a medium-temperature cured carbon fiber prepreg to improve the brittleness of the epoxy resin and increase its elongation at break to achieve a toughening effect and a composite material molding process; and the preparation method is simple, the conditions are mild, the controllability is good, and it is more suitable for industrial application and promotion.

[0006] The present invention provides a polyurethane modified epoxy resin material for prepreg, which comprises, by weight of raw materials:

[0007]

[0008] Preferably, the weight average molecular weight of the polyester is 1000 to 3000;

[0009] The weight average molecular weight of the polyether polyol is 1000 to 3000;

[0010] The polyether polyol comprises polytetramethylene glycol and / or polyoxypropylene glycol.

[0011] Preferably, the polyester comprises polycaprolactone diol and / or polyethylene adipate polyol;

[0012] The isocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate trimer;

[0013] The chain extender and curing agent include 3,3'-dichloro-4,4'-diaminodiphenylmethane and / or diethyltoluenediamine.

[0014] Preferably, the light stabilizer comprises triphenyl phosphite;

[0015] The antioxidant includes antioxidant 1135;

[0016] The ultraviolet absorber includes ultraviolet absorber UV-531.

[0017] The present invention provides a method for preparing a polyurethane-modified epoxy resin material for prepreg as described in any one of the above technical solutions, comprising the following steps:

[0018] 1) mixing polyester or polyether polyol and isocyanate, and reacting them under a protective atmosphere to obtain a prepolymer;

[0019] 2) adding epoxy resin to the prepolymer obtained in the above step, reacting again under a protective atmosphere to obtain a modified epoxy resin;

[0020] 3) The modified epoxy resin, curing agent, chain extender, light stabilizer, antioxidant and ultraviolet absorber obtained in the above steps are placed in a mold for curing to obtain a polyurethane modified epoxy resin material.

[0021] Preferably, the polyether polyol is a pretreated polyether polyol;

[0022] The pretreatment step specifically comprises heating the polyether polyol and then performing reduced pressure distillation to remove water.

[0023] Preferably, the heating temperature is 110-130°C;

[0024] The time for removing water by reduced pressure distillation is 2 to 3 hours.

[0025] Preferably, the reaction temperature is 70-90°C;

[0026] The reaction time is 2 to 3 hours;

[0027] The mass fraction of isocyanate groups in the prepolymer is 5% to 30%.

[0028] Preferably, the temperature of the second reaction is 100-120°C;

[0029] The second reaction time is 4 to 6 hours;

[0030] The curing temperature is 80-180°C;

[0031] The curing time is 12 to 18 hours.

[0032] The present invention also provides the use of the polyurethane-modified epoxy resin material described in any one of the above technical solutions or the polyurethane-modified epoxy resin material prepared by the preparation method described in any one of the above technical solutions in a prepreg resin system or a medium-temperature cured carbon fiber prepreg.

[0033] The present invention provides a polyurethane modified epoxy resin material for prepreg, which comprises, by weight of raw materials, 10 to 35 parts of polyester or polyether polyol, 1 to 10 parts of isocyanate, 40 to 70 parts of epoxy resin, 1 to 3 parts of light stabilizer, 1 to 2 parts of antioxidant, 1 to 2 parts of ultraviolet absorber, and 5 to 30 parts of chain extender and curing agent. Compared with the prior art, the present invention specially designs a polyurethane modified epoxy resin material for prepreg with specific components and structure, prepares intrinsic flexible epoxy resin by grafting modification of polyurethane prepolymer, and is applied to prepreg resin system and medium temperature curing carbon fiber prepreg, improves the brittleness of epoxy resin, and increases its elongation at break, so as to achieve toughening effect and composite material molding process.

[0034] The present invention grafts and modifies a polyurethane prepolymer onto an epoxy resin to improve the toughness of the epoxy resin prepreg; regulates the fluidity of the epoxy resin to prevent it from being cast, thereby achieving the low creep requirement of the prepreg; the glass transition temperature is greater than 80°C, and at the same time, there is no creep or a small creep at room temperature (10-30°C), that is, the increase in long-term creep deformation under a load of 4MPa is less than 0.2, and the viscosity is adjustable, the hand is not sticky at low temperature, and the hand does not flow, the viscosity is about 20,000 at 40-80°C, there is no reaction at -18°C, and there is no reaction at room temperature for 7 days. DETAILED DESCRIPTION

[0035] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0036] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0037] There is no particular restriction on the purity of all raw materials in the present invention. The present invention preferably uses industrial pure materials or conventional purities used in the field of epoxy resin prepreg preparation.

[0038] All noun expressions, abbreviations and trademarks in the present invention are conventional noun expressions, abbreviations and trademarks in the field. Each noun expression, abbreviation and trademark is clear and unambiguous in its relevant application field, and those skilled in the art can clearly, accurately and uniquely understand it based on the noun expressions, abbreviations and trademarks.

[0039] The present invention provides a polyurethane modified epoxy resin material for prepreg, which comprises, by weight of raw materials:

[0040]

[0041] In the present invention, the polyester or polyether polyol is added in an amount of 10 to 35 parts by weight, may be 15 to 30 parts by weight, or may be 20 to 25 parts by weight.

[0042] In the present invention, the amount of the isocyanate added is 1 to 10 parts by weight, can be 3 to 8 parts by weight, can be 5 to 6 parts by weight.

[0043] In the present invention, the epoxy resin is added in an amount of 40 to 70 parts by weight, 45 to 65 parts by weight, or 50 to 60 parts by weight.

[0044] In the present invention, the amount of the light stabilizer added is 1 to 3 parts by weight, can be 1.4 to 2.6 parts by weight, can be 1.8 to 2.2 parts by weight.

[0045] In the present invention, the antioxidant is added in an amount of 1 to 2 parts by weight, may be 1.2 to 1.8 parts by weight, or may be 1.4 to 1.6 parts by weight.

[0046] In the present invention, the added amount of the ultraviolet absorber is 1 to 2 parts by weight, can be 1.2 to 1.8 parts by weight, can be 1.4 to 1.6 parts by weight.

[0047] In the present invention, the added amount of the chain extender and the curing agent is 5 to 30 parts by weight, can be 10 to 25 parts by weight, can be 15 to 20 parts by weight.

[0048] In the present invention, the weight average molecular weight of the polyester is preferably 1000-3000, more preferably 1400-2600, and even more preferably 1800-2200.

[0049] In the present invention, the weight average molecular weight of the polyether polyol is preferably 1000-3000, more preferably 1400-2600, and even more preferably 1800-2200.

[0050] In the present invention, the polyether polyol preferably comprises polytetrahydrofuran diol and / or polyoxypropylene diol, more preferably polytetrahydrofuran diol or polyoxypropylene diol. Specifically, the polyether polyol can be a polyether polyol with a functionality of 2.

[0051] In the present invention, the polyester preferably includes polycaprolactone diol (PCL) and / or polyethylene adipate polyol, more preferably polycaprolactone diol (PCL) or polyethylene adipate polyol. Specifically, the polyester may be a polyester with a functionality of 2.

[0052] In the present invention, the isocyanate preferably includes one or more of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate trimer, and more preferably toluene diisocyanate, diphenylmethane diisocyanate or hexamethylene diisocyanate trimer.

[0053] In the present invention, the chain extender and curing agent (chain extender / curing agent) preferably include 3,3'-dichloro-4,4'-diaminodiphenylmethane and / or diethyltoluenediamine, more preferably 3,3'-dichloro-4,4'-diaminodiphenylmethane or diethyltoluenediamine.

[0054] In the present invention, the light stabilizer preferably includes triphenyl phosphite.

[0055] In the present invention, the antioxidant preferably includes antioxidant 1135.

[0056] In the present invention, the ultraviolet absorber preferably includes ultraviolet absorber UV-531.

[0057] The present invention provides a method for preparing a polyurethane-modified epoxy resin material for prepreg as described in any one of the above technical solutions, comprising the following steps:

[0058] 1) mixing polyester or polyether polyol and isocyanate, and reacting them under a protective atmosphere to obtain a prepolymer;

[0059] 2) adding epoxy resin to the prepolymer obtained in the above step, reacting again under a protective atmosphere to obtain a modified epoxy resin;

[0060] 3) The modified epoxy resin, curing agent, chain extender, light stabilizer, antioxidant and ultraviolet absorber obtained in the above steps are placed in a mold for curing to obtain a polyurethane modified epoxy resin material.

[0061] The invention firstly mixes polyester or polyether polyol and isocyanate, and reacts them under a protective atmosphere to obtain a prepolymer.

[0062] In the present invention, the polyether polyol is preferably a pretreated polyether polyol.

[0063] In the present invention, the pretreatment step is preferably to heat the polyether polyol and then perform reduced pressure distillation to remove water.

[0064] In the present invention, the heating temperature is preferably 110-130°C, more preferably 114-126°C, and more preferably 118-122°C.

[0065] In the present invention, the time for removing water by reduced pressure distillation is preferably 2 to 3 hours, more preferably 2.2 to 2.8 hours, and more preferably 2.4 to 2.6 hours.

[0066] In the present invention, the reaction temperature is preferably 70 to 90°C, more preferably 74 to 86°C, and more preferably 78 to 82°C.

[0067] In the present invention, the reaction time is preferably 2 to 3 hours, more preferably 2.2 to 2.8 hours, and more preferably 2.4 to 2.6 hours.

[0068] In the present invention, the mass fraction of the isocyanate groups in the prepolymer is preferably 5% to 30%, more preferably 10% to 25%, and more preferably 15% to 20%.

[0069] The present invention further places the modified epoxy resin, curing agent, chain extender, light stabilizer, antioxidant and ultraviolet absorber obtained in the above steps in a mold for curing to obtain a polyurethane modified epoxy resin material.

[0070] In the present invention, the temperature of the secondary reaction is preferably 100-120°C, more preferably 104-116°C, and more preferably 108-112°C.

[0071] In the present invention, the second reaction time is preferably 4 to 6 hours, more preferably 4.4 to 5.6 hours, and more preferably 4.8 to 5.2 hours.

[0072] Finally, the modified epoxy resin, curing agent, chain extender, light stabilizer, antioxidant and ultraviolet absorber obtained in the above steps are placed in a mold for curing to obtain a polyurethane modified epoxy resin material.

[0073] In the present invention, the curing system is preferably a step-temperature curing system.

[0074] In the present invention, the curing temperature is preferably 80 to 180°C, more preferably 100 to 160°C, and even more preferably 120 to 140°C.

[0075] In the present invention, the curing time is preferably 12 to 18 hours, more preferably 13 to 17 hours, and more preferably 14 to 16 hours.

[0076] The present invention provides the use of the polyurethane modified epoxy resin material described in any one of the above technical solutions or the polyurethane modified epoxy resin material prepared by the preparation method described in any one of the above technical solutions in a prepreg resin system or a medium-temperature cured carbon fiber prepreg.

[0077] The present invention is a complete and detailed overall technical solution, which better ensures the composition and structure of the polyurethane modified epoxy resin material, further improves the elongation at break of the polyurethane modified epoxy resin material, and further improves the toughening effect of the prepreg resin and the molding process of the prepreg. The above-mentioned polyurethane modified epoxy resin material for prepreg and its preparation method and application can specifically include the following contents:

[0078] 10-30 parts by weight of polyester or polyether polyol, 1-10 parts by weight of isocyanate, 5-25 parts by weight of chain extender and curing agent, 40-70 parts by weight of epoxy resin, 1-3 parts by weight of light stabilizer, 1-3 parts by weight of antioxidant, and 1-3 parts by weight of ultraviolet absorber.

[0079] Weigh a certain amount of polyol and remove water by vacuum distillation at 110℃~130℃ for 2-3h, cool to 60-70℃ for use. Add polyol and isocyanate to a three-necked flask, then stir evenly at 70-90℃ nitrogen atmosphere, measure NCO content after 2-3h, until the reaction reaches the theoretical value, and obtain the required prepolymer. Add prepolymer to epoxy resin, react at 100℃-120℃ under nitrogen atmosphere for 4-6h to ensure that all polyurethane prepolymers are grafted onto epoxy resin. Mix the epoxy resin modified by polyurethane prepolymer grafting with curing agent (DETDA) in proportion, pour the stirred mixture into a mold, cure at 80℃-180℃, and then place at room temperature for 7 days for testing.

[0080] Specifically, the molecular weight of the polyester or polyether polyol is in the range of 1000 to 3000.

[0081] Specifically, one or a combination of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and hexamethylene diisocyanate trimer.

[0082] Specifically, the chain extender and the curing agent are one or a combination of 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA) and diethyltoluenediamine (DETDA) E100.

[0083] Specifically, the light stabilizer is triphenyl phosphite.

[0084] Specifically, the antioxidant is 1135.

[0085] Specifically, the ultraviolet absorber is 531.

[0086] The above content of the present invention provides a polyurethane modified epoxy resin prepreg material (resin raw material for preparing prepreg) and a preparation method thereof. The polyurethane modified epoxy resin material for prepreg specially designed by the present invention with specific components and structures is used to prepare intrinsic flexible epoxy resin by grafting modification with polyurethane prepolymer, and is applied to prepreg resin system and medium temperature curing carbon fiber prepreg to improve the brittleness of epoxy resin and increase its elongation at break, so as to achieve toughening effect and composite material molding process.

[0087] The present invention grafts and modifies a polyurethane prepolymer onto an epoxy resin to improve the toughness of the epoxy resin prepreg; regulates the fluidity of the epoxy resin to prevent it from being cast, thereby achieving the low creep requirement of the prepreg; the glass transition temperature is greater than 80°C, and at the same time, there is no creep or a small creep at room temperature (10-30°C), that is, the increase in long-term creep deformation under a load of 4MPa is less than 0.2, and the viscosity is adjustable, the hand is not sticky at low temperature, and the hand does not flow, the viscosity is about 20,000 at 40-80°C, there is no reaction at -18°C, and there is no reaction at room temperature for 7 days.

[0088] In order to further illustrate the present invention, a polyurethane-modified epoxy resin material for prepreg provided by the present invention and its preparation method and application are described in detail below in combination with embodiments. However, it should be understood that these embodiments are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following embodiments.

[0089] Example 1

[0090] 23.6 parts by weight of polyether polyol (polytetrahydrofuran diol 3000) were added to the reactor, dehydrated at 120°C for 2h under nitrogen protection, cooled to 75°C, 1.6 parts by weight of 2,4-toluene diisocyanate (TDI) were added, and the mixture was reacted for 2h under nitrogen protection to obtain the mixture, and its NCO content was measured. 60.3 parts by weight of epoxy resin were added, mixed, and light stabilizers were added, such as 1 part by weight of triphenyl phosphite, 1 part by weight of antioxidant, and 1 part by weight of ultraviolet absorber. The mixture was reacted at 100°C-120°C for 4-6h under nitrogen atmosphere. 11.5 parts by weight of chain extender (DETDA) and curing agent (DETDA) were added, and the mixture was poured into a mold and cured at 80°C-2h-120°C-2h-160°C-2h-180°C-2h-120°C-10h, and then placed at room temperature for 7 days for testing.

[0091] Example 2

[0092] 27.6 parts by weight of polyether polyol (polytetrahydrofuran diol 3000) were added to the reactor, dehydrated at 120°C for 2h under nitrogen protection, cooled to 75°C, added 2.5 parts by weight of 2,4-toluene diisocyanate (TDI), reacted under nitrogen protection for 2h to obtain a mixture, and its NCO content was measured. 55.7 parts by weight of epoxy resin were added, mixed, and a light stabilizer of 1 part by weight of triphenyl phosphite, 1 part by weight of antioxidant, and 1 part by weight of ultraviolet absorber were added. Reacted at 100°C-120°C for 4-6h under nitrogen atmosphere. 11.2 parts by weight of chain extender (DETDA) and curing agent (DETDA) were added, and the stirred mixture was poured into a mold and cured at 80°C-2h-120°C-2h-160°C-2h-180°C-2h-120°C-10h, and then placed at room temperature for 7 days for testing.

[0093] Example 3

[0094] 33.5 parts by weight of polyether polyol (polytetrahydrofuran diol 3000) were added to the reactor, dehydrated at 120°C for 2h under nitrogen protection, cooled to 75°C, 2.7 parts by weight of 2,4-toluene diisocyanate (TDI) were added, reacted for 2h under nitrogen protection to obtain a mixture, and its NCO content was measured. 50 parts by weight of epoxy resin were added, mixed, and light stabilizers were added, such as 1 part by weight of triphenyl phosphite, 1 part by weight of antioxidant, and 1 part by weight of ultraviolet absorber. Reacted at 100°C-120°C for 4-6h under nitrogen atmosphere. 10.8 parts by weight of chain extender (DETDA) and curing agent (DETDA) were added, and the stirred mixture was poured into a mold and cured at 80°C-2h-120°C-2h-160°C-2h-180°C-2h-120°C-10h, and then placed at room temperature for 7 days for testing.

[0095] Comparative Example 1

[0096] This comparative example provides a method for preparing a wide temperature range damping polyurethane material, which is different from Example 1 in that no polyurethane prepolymer is added in Comparative Example 1.

[0097] Mix 81 parts by weight of epoxy resin and 16 parts by weight of curing agent (DETDA), add 1 part of light stabilizer, 1 part of antioxidant and 1 part of UV absorber, pour the evenly stirred mixture into a mold and cure it at 80℃-2h-120℃-2h-160℃-2h-180℃-2h-120℃-10h, then place it at room temperature for 7 days for testing.

[0098] Performance Test:

[0099] The test results are shown in Table 1, which shows the performance data of the epoxy resins prepared in the examples and comparative examples of the present invention.

[0100] Table 1

[0101]

[0102] The above is a detailed introduction to a polyurethane-modified epoxy resin prepreg material provided by the present invention, its preparation method and application. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and its core ideas of the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including the manufacture and use of any device or system, and the implementation of any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the text of the claims, or if they include equivalent structural elements that are not substantially different from the text of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A polyurethane modified epoxy resin material for prepreg, characterized in that: Calculated by weight of raw materials, including:

2. The polyurethane modified epoxy resin material according to claim 1, characterized in that: The weight average molecular weight of the polyester is 1000 to 3000; The weight average molecular weight of the polyether polyol is 1000 to 3000; The polyether polyol comprises polytetramethylene glycol and / or polyoxypropylene glycol.

3. The polyurethane modified epoxy resin material according to claim 1, characterized in that: The polyester comprises polycaprolactone diol and / or polyethylene adipate polyol; The isocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate trimer; The chain extender and curing agent include 3,3'-dichloro-4,4'-diaminodiphenylmethane and / or diethyltoluenediamine.

4. The polyurethane modified epoxy resin material according to claim 1, characterized in that: The light stabilizer includes triphenyl phosphite; The antioxidant includes antioxidant 1135; The ultraviolet absorber includes ultraviolet absorber UV-531.

5. A method for preparing a polyurethane modified epoxy resin material for prepreg according to any one of claims 1 to 4, characterized in that: The following steps are involved: 1) mixing polyester or polyether polyol and isocyanate, and reacting them under a protective atmosphere to obtain a prepolymer; 2) adding epoxy resin to the prepolymer obtained in the above step, reacting again under a protective atmosphere to obtain a modified epoxy resin; 3) The modified epoxy resin, curing agent, chain extender, light stabilizer, antioxidant and ultraviolet absorber obtained in the above steps are placed in a mold for curing to obtain a polyurethane modified epoxy resin material.

6. The preparation method according to claim 5, characterized in that: The polyether polyol is specifically a pretreated polyether polyol; The pretreatment step specifically comprises heating the polyether polyol and then performing reduced pressure distillation to remove water.

7. The preparation method according to claim 6, characterized in that: The heating temperature is 110-130°C; The time for removing water by reduced pressure distillation is 2 to 3 hours.

8. The preparation method according to claim 5, characterized in that: The reaction temperature is 70-90°C; The reaction time is 2 to 3 hours; The mass fraction of isocyanate groups in the prepolymer is 5% to 30%.

9. The preparation method according to claim 5, characterized in that: The temperature of the second reaction is 100-120°C; The second reaction time is 4 to 6 hours; The curing temperature is 80-180°C; The curing time is 12 to 18 hours.

10. Use of the polyurethane-modified epoxy resin material according to any one of claims 1 to 4 or the polyurethane-modified epoxy resin material prepared by the preparation method according to any one of claims 5 to 9 in a prepreg resin system or a medium-temperature cured carbon fiber prepreg.

Images