Polyurethane acrylate elastomer, preparation method and application

Abstract

The invention discloses a polyurethane acrylate elastomer as well as a preparation method and application thereof, and the preparation method comprises the following steps: (1) dissolving micromolecular diamine in toluene to prepare a diamine solution, introducing nitrogen at 70 DEG C, adding diisocyanate containing acrylate functional groups and a first catalyst, and continuously stirring for 6-12 hours to obtain a prepolymer (1); (2) carrying out dehydration treatment on oligomer dihydric alcohol at 100-120 DEG C under a vacuum condition for 2 hours, cooling to 70 DEG C, introducing nitrogen, adding diisocyanate and a second catalyst, and continuously stirring for 3-12 hours to obtain a prepolymer (2); (3) adding the prepolymer (1) into the prepolymer (2), and stirring at 70 DEG C for 3-6 hours to obtain a prepolymer (3); and (4) adding a hydroxyl acrylate end-capping reagent into the prepolymer (3) to obtain the elastomer. The reactivity of the whole system is improved by improving the density of acrylate double bonds in the polyurethane elastomer, and the purpose of low-temperature rapid curing is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a polyurethane acrylate elastomer, a preparation method and application thereof. Background Art

[0002] Polyurethane elastomer is a polymer material between rubber and plastic, with some excellent properties of both rubber and plastic. As an elastomer, it is widely used in various fields such as chemical industry, electronics, national defense, construction, medical treatment, automobile, etc.

[0003] As semiconductor components become more integrated and liquid crystal elements become more sophisticated, the spacing between components and lines is becoming narrower, so the heating during curing has an adverse effect on the materials of surrounding components. In addition, in order to reduce costs and increase production, low-temperature and rapid curing is required.

[0004] Currently, most of the anisotropic conductive films (ACF) prepared in the industry use polyurethane elastomers or acrylate-terminated polyurethane elastomers as the elastomers of the free radical system ACF. Since polyurethane elastomers lack functional groups that participate in the reaction or the number of reactive functional groups is insufficient, it is difficult to effectively improve the strength of the material and thus achieve a low-temperature rapid curing effect.

[0005] Therefore, it is of great practical significance to develop a polyurethane acrylate elastomer and a preparation method thereof, to obtain a target bonding strength by regulating the density of acrylate in the polyurethane molecular chain, and to improve the degree of reaction, so as to achieve low-temperature rapid curing. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention provides a polyurethane acrylate elastomer, a preparation method and an application thereof. The present invention increases the reactivity of the entire system by molecular designing the polyurethane molecular chain and regulating the double bond density on the polyurethane molecular chain, thereby achieving low-temperature rapid curing, thereby reducing costs and increasing production. At the same time, by regulating the molecular weight of polyurethane acrylate, replacing the film-forming resin, reducing the microphase separation caused by polarity problems in the system, the material dispersion in the film is made more uniform.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a polyurethane acrylate elastomer comprises the following steps:

[0009] (1) Dissolving a small molecular weight diamine in toluene to obtain a diamine solution, introducing nitrogen at 70° C. and adding a diisocyanate containing an acrylate functional group and a first catalyst, and continuously stirring for 6 to 12 hours to obtain an amino-terminated prepolymer①;

[0010] The molar ratio of the small molecule diamine to the diisocyanate containing an acrylate functional group is 1.1 to 2.5:1; the first catalyst is 0.01 to 1% of the total mass of the system in step (1);

[0011] (2) Dehydrating the oligomer diol at 100-120° C. under vacuum for 2 h, cooling to 70° C., introducing nitrogen, adding diisocyanate and a second catalyst, and continuously stirring for 3-12 h to obtain an isocyanate-terminated prepolymer ②;

[0012] The molar ratio of diisocyanate to oligomer diol is 1.1 to 2.5:1; the second catalyst is 0.01 to 1% of the total mass of the system in step (2);

[0013] (3) adding prepolymer ① to prepolymer ②, stirring at 70° C. for 3 to 6 hours, to obtain isocyanate-terminated prepolymer ③; the molar ratio of prepolymer ② to prepolymer ① is 1.1 to 2.5:1;

[0014] (4) adding a hydroxy acrylate end-capping agent to the prepolymer ③, wherein the molar ratio of the hydroxy acrylate end-capping agent to the prepolymer ③ is 2.05 to 5.0:1; and using infrared detection until the characteristic peak of the isocyanate group completely disappears, thereby obtaining an acrylate-blocked, acrylate-terminated polyurethane acrylate elastomer.

[0015] Preferably, the small molecule diamine is naphthyridine diamine, and the structure is as follows:

[0016]

[0017] Among them, R8, R9, R 10 ,R 11 It is H or an integer representing the number of carbon atoms of 1 to 12.

[0018] More preferably, the small molecule diamine is 1,8-naphthyridine-2,7-diamine, and the structure is as follows:

[0019]

[0020] Preferably, the structure of the diisocyanate containing acrylate functional groups is:

[0021]

[0022] or:

[0023] in, It refers to aliphatic, aromatic, alicyclic or araliphatic; R1, R2, R3, R4, R5, R6, R7 are H or an integer representing the number of carbon atoms of 1 to 12.

[0024] Preferably, the diisocyanate is one or a combination of pure aromatic diisocyanate, pure aliphatic diisocyanate, aromatic aliphatic diisocyanate and cycloaliphatic diisocyanate.

[0025] More preferably, the diisocyanate is 4-chloromethyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-m-phenylene diisocyanate, 3,3-dichlorobiphenyl-4,4-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, m-phenylene diisocyanate, m-phenylene diisocyanate, dimethyl biphenyl diisocyanate, polymethylene polyphenyl diisocyanate, phenylene diisocyanate, One or a combination of methylene diisocyanate, tetramethyl meta-xylylene diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexyl diisocyanate, methane cyclohexyl diisocyanate, cyclohexane dimethylene diisocyanate, norbornane diisocyanate, 1,6-hexamethylene diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, and L-lysine diisocyanate.

[0026] Preferably, the hydroxyacrylate end-capping agent is one or a combination of hydroxyacrylates, hydroxydiacrylates, and hydroxytriacrylates.

[0027] More preferably, the hydroxyacrylate end-capping agent is one or a combination of hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-propyl methacrylate, and pentaerythritol triacrylate.

[0028] Preferably, the first catalyst and the second catalyst are one or a combination of organic bismuth, organic zinc, organic iron, and organic tertiary amine.

[0029] More preferably, the first catalyst and the second catalyst are one or a combination of triethylenediamine, bis(dimethylaminoethyl) ether, N-ethylmorpholine, tetramethyldipropylenetriamine, iron octoate, bismuth carboxylate, and zinc cyclohexaneate.

[0030] Preferably, the oligomer diol is one or a combination of polyoxypropylene diol, polyoxyethylene diol, adipic acid polyester diol, succinic acid polyester diol, isophthalic acid polyester diol, terephthalic acid polyester diol, polycarbonate diol, polycaprolactone diol, polytetramethylene glycol, polysiloxane diol, and polyether diol.

[0031] The structure of the prepolymer ① is as follows:

[0032]

[0033] The structure of the prepolymer ② is as follows:

[0034]

[0035] The structure of the prepolymer ③ is as follows:

[0036]

[0037] The polyurethane acrylate elastomer structure is as follows:

[0038]

[0039] Among them, m=6~30, n=1~10.

[0040] The reaction formula of the above step (1) is as follows:

[0041]

[0042] The reaction formula of the above step (2) is as follows:

[0043] The reaction formula of the above step (3) is as follows:

[0044] The reaction formula of the above step (4) is as follows:

[0045]

[0046] In the above reaction formula of step (1) to step (4), represents oligomer diol, represents diisocyanate; m=6-30, n=1-10.

[0047] Another object of the present invention is to disclose the polyurethane acrylate elastomer prepared by the above method.

[0048] Another object of the present invention is to disclose the application of the above-mentioned polyurethane acrylate elastomer in an ACF free radical system.

[0049] Specifically disclosed is a free radical system anisotropic conductive material, comprising a PET release film and a conductive film arranged on the release film.

[0050] The conductive film comprises the following components by weight:

[0051]

[0052] The conductive film is prepared by the following method: reactive materials, the above-mentioned polyurethane acrylate elastomer, fillers, inhibitors, and conductive particles are added into a three-necked flask, butanone is used as a solvent, and a 33% solid content resin solution is prepared, and the solution is stirred at 80-100° C. until the components are uniformly dispersed, and then heating is stopped and stirring is continued for 1 hour, and the solution is cooled to room temperature, and an initiator is added and stirred for 1 hour to obtain a coating liquid; the prepared coating liquid is scraped onto a PET release film, and baked at 40-100° C. for 5-10 minutes, and the conductive film is obtained after drying.

[0053] Preferably, the reactive material is acrylic, acrylate, vinyl ether, epoxy resin or polyester acrylate.

[0054] Preferably, the filler is silicon dioxide, acrylic microspheres, styrene microspheres, titanium dioxide, calcium carbonate or barium sulfate.

[0055] Preferably, the initiator is a peroxide.

[0056] Preferably, the polymerization inhibitor is phenol, quinone, hindered phenol or hindered amine.

[0057] Preferably, the conductive particles are conductive microspheres or conductive metal powders.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The invention increases the density of double bonds of acrylate in the polyurethane elastomer to increase the reactivity of the free radical system ACF, thereby achieving the purpose of rapid curing.

[0060] In the ACF of the free radical system, the present invention can effectively avoid microphase separation caused by material polarity problems by increasing the density of acrylate on the polyurethane elastomer structure, make the raw materials more evenly dispersed, and effectively improve the impact resistance and electrical conductivity of the material.

[0061] The present invention introduces small molecule diamine into polyurethane, provides allophanate bonds, can form quadruple hydrogen bonds between molecules, can induce phase separation to form soft and hard segment structures, form stable microcrystals at ambient temperature, and further improve the mechanical properties of polyurethane elastomers. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is the infrared spectra of the products of Examples 1 to 3 and Comparative Examples 1 to 2. DETAILED DESCRIPTION

[0063] The following are embodiments of the present invention. The present invention is further described in conjunction with the embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and do not constitute a limitation on the protection scope of the present invention.

[0064] Unless otherwise specified, the raw materials and equipment used in the embodiments of the present invention are commonly used in the art and are commercially available.

[0065] The present invention provides a method for preparing a polyurethane acrylate elastomer, comprising the following steps:

[0066] (1) Dissolving a small molecular weight diamine in toluene to obtain a diamine solution, introducing nitrogen at 70° C. and adding a diisocyanate containing an acrylate functional group and a first catalyst, and continuously stirring for 6 to 12 hours to obtain an amino-terminated prepolymer①;

[0067] The molar ratio of the small molecule diamine to the diisocyanate containing an acrylate functional group is 1.1 to 2.5:1; the first catalyst is 0.01 to 1% of the total mass of the system in step (1);

[0068] (2) Dehydrating the oligomer diol at 100-120° C. under vacuum for 2 h, cooling to 70° C., introducing nitrogen, adding diisocyanate and a second catalyst, and continuously stirring for 3-12 h to obtain an isocyanate-terminated prepolymer ②;

[0069] The molar ratio of diisocyanate to oligomer diol is 1.1 to 2.5:1; the second catalyst is 0.01 to 1% of the total mass of the system in step (2);

[0070] (3) adding prepolymer ① to prepolymer ②, stirring at 70° C. for 3 to 6 hours, to obtain isocyanate-terminated prepolymer ③; the molar ratio of prepolymer ② to prepolymer ① is 1.1 to 2.5:1;

[0071] (4) adding a hydroxy acrylate end-capping agent to the prepolymer ③, wherein the molar ratio of the hydroxy acrylate end-capping agent to the prepolymer ③ is 2.05 to 5.0:1; and using infrared detection until the characteristic peak of the isocyanate group completely disappears, thereby obtaining an acrylate-blocked, acrylate-terminated polyurethane acrylate elastomer.

[0072] The small molecule diamine is naphthyridine diamine. In some embodiments, the small molecule diamine is preferably 1,8-naphthyridine-2,7-diamine.

[0073] The structure of diisocyanate containing acrylate functional group is:

[0074]

[0075] or:

[0076] in, R1, R2, R3, R4, R5, R6, R7 are H or integers representing carbon number of 1 to 12. In some embodiments, the diisocyanate containing acrylate functional group is preferably diacrylate diisocyanate.

[0077] The diisocyanate is one or a combination of pure aromatic diisocyanate, pure aliphatic diisocyanate, aromatic aliphatic diisocyanate, and cycloaliphatic diisocyanate. In some embodiments, the diisocyanate is preferably 4-chloromethyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-m-phenylene diisocyanate, 3,3-dichlorobiphenyl-4,4-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, m-phenylene diisocyanate, dimethyl biphenyl diisocyanate, polymethylene polyphenyl diisocyanate, benzene One or a combination of methylene diisocyanate, tetramethyl meta-xylylene diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexyl diisocyanate, methane cyclohexyl diisocyanate, cyclohexane dimethylene diisocyanate, norbornane diisocyanate, 1,6-hexamethylene diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, and L-lysine diisocyanate.

[0078] The hydroxyacrylate end-capping agent is one or a combination of hydroxyacrylates, hydroxydiacrylates, and hydroxytriacrylates. In some embodiments, the hydroxyacrylate end-capping agent is preferably one or a combination of hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-propyl methacrylate, and pentaerythritol triacrylate.

[0079] The first catalyst and the second catalyst are one or a combination of organic bismuth, organic zinc, organic iron, and organic tertiary amines. In some embodiments, the first catalyst and the second catalyst are preferably one or a combination of triethylenediamine, bis(dimethylaminoethyl) ether, N-ethylmorpholine, tetramethyldipropylenetriamine, iron octanoate, bismuth carboxylate, and zinc cyclohexaneate.

[0080] The oligomer diol is one or a combination of polyoxypropylene diol, polyoxyethylene diol, adipic acid polyester diol, succinic acid polyester diol, isophthalic acid polyester diol, terephthalic acid polyester diol, polycarbonate diol, polycaprolactone diol, polytetramethylene glycol, polysiloxane diol, and polyether diol.

[0081] The polyurethane acrylate elastomer prepared above can be used in the ACF free radical system. For example:

[0082] A free radical system anisotropic conductive material comprises a PET release film and a conductive film arranged on the release film.

[0083] The conductive film comprises the following components by weight:

[0084]

[0085] The conductive film is prepared by the following method: reactive materials, the above-mentioned polyurethane acrylate elastomer, fillers, polymerization inhibitors, and conductive particles are added into a three-necked flask, butanone is used as a solvent to prepare a resin solution with a solid content of 33%, and the solution is stirred at 80-100° C. until all components are evenly dispersed, and then heating is stopped and stirring is continued for 1 hour, and the solution is cooled to room temperature, and an initiator is added and stirred for 1 hour to obtain a coating liquid; the prepared coating liquid is scraped onto a PET release film, and the solution is baked at 40-100° C. for 5-10 minutes, and the conductive film is obtained after drying.

[0086] The reactive material is acrylic acid, acrylic acid ester, vinyl ether, epoxy resin or polyester acrylate. The filler is silicon dioxide, acrylic acid ester microspheres, styrene microspheres, titanium dioxide, calcium carbonate or barium sulfate. The initiator is peroxide. The inhibitor is phenol, quinone, hindered phenol or hindered amine. The conductive particles are conductive microspheres or conductive metal powder.

[0087] In order to illustrate the advantages of the present invention, the following is described by comparing Examples 1-3 with Comparative Examples 1-2:

[0088] Example 1

[0089] A method for preparing a polyurethane acrylate elastomer comprises the following steps:

[0090] ⑴ Weigh 40g (0.2496mol) of a small molecule diamine (1,8-naphthyridine-2,7-diamine) and dissolve it in toluene to obtain a diamine solution with a solid content of 10%, add it into a three-necked flask, introduce nitrogen at 70°C and add 69.264g (0.1248mol) of diacrylate diisocyanate and 0.1093g (0.0010mol) of a catalyst (triethylenediamine), and continue stirring for 6h to obtain an amino-terminated prepolymer①.

[0091] ⑵ Weigh 100g (0.1mol) of 1000g / mol polycarbonate diol and dehydrate it under vacuum at 120℃ for 2h, cool it to 70℃, introduce nitrogen and add 32.5388g (0.13mol) of diphenylmethane diisocyanate, and continue stirring for 3h to obtain an isocyanate-terminated prepolymer②.

[0092] ⑶ Add 13.1327 g (0.015 mol) of pure prepolymer ① to prepolymer ②, stir at 70°C for 6 hours to obtain isocyanate-terminated prepolymer ③.

[0093] (4) Finally, 4.1803 g (0.036 mol) of hydroxyethyl acrylate as a blocking agent was added, and infrared detection was performed until the characteristic peak of the isocyanate group completely disappeared, thereby obtaining an acrylate-blocked and acrylate-terminated polyurethane elastomer.

[0094] A free radical system anisotropic conductive material comprises a PET release film and a conductive film arranged on the release film. The resin used to prepare the conductive film comprises the following weight components: 16g of methyl methacrylate, 21g of polyester acrylic resin, 40g of the above-prepared polyurethane acrylate elastomer, 6g of filler silica, 1.5g of initiator cumene peroxide, 0.5g of inhibitor p-hydroxyphenol, and 15g of conductive microspheres.

[0095] The preparation process is as follows: add all components except the initiator into a three-necked flask, use butanone as a solvent to prepare a resin solution with a solid content of 33%, stir at 80°C until all components are evenly dispersed, stop heating and continue stirring for 1 hour, cool to room temperature, add the initiator and stir for 1 hour to obtain a coating liquid; apply the prepared coating liquid on a PET release film, bake at 60°C for 5 minutes, and obtain a conductive film after drying.

[0096] Example 2

[0097] A method for preparing a polyurethane acrylate elastomer comprises the following steps:

[0098] ⑴ Weigh 40g (0.2496mol) of a small molecule diamine (1,8-naphthyridine-2,7-diamine) and dissolve it in toluene to obtain a diamine solution with a solid content of 10%. Add it into a three-necked flask, introduce nitrogen at 70°C and add 69.264g (0.1248mol) of diacrylate diisocyanate and 0.1093g (0.0010mol) of a catalyst (triethylenediamine). Continue stirring for 6h to obtain an amino-terminated prepolymer①.

[0099] ⑵ Weigh 100g (0.1mol) of 1000g / mol polycarbonate diol and dehydrate it under vacuum at 120℃ for 2h, cool it to 70℃, introduce nitrogen and add 40.0416g (0.16mol) of diphenylmethane diisocyanate, and continue stirring for 3h to obtain an isocyanate-terminated prepolymer②.

[0100] ⑶ Add 26.2654 g (0.03 mol) of pure prepolymer ① to prepolymer ②, and stir at 70° C. for 6 h to obtain isocyanate-terminated prepolymer ③.

[0101] (4) Finally, 8.3606 g (0.072 mol) of hydroxyethyl acrylate as a blocking agent was added, and infrared detection was performed until the characteristic peak of the isocyanate group completely disappeared, thereby obtaining an acrylate-blocked and acrylate-terminated polyurethane elastomer.

[0102] A free radical system anisotropic conductive material, the preparation formula and method are the same as those in Example 1.

[0103] Example 3

[0104] A method for preparing a polyurethane acrylate elastomer comprises the following steps:

[0105] ⑴ Weigh 40g (0.2496mol) of a small molecule diamine (1,8-naphthyridine-2,7-diamine) and dissolve it in toluene to obtain a diamine solution with a solid content of 10%. Add it into a three-necked flask, introduce nitrogen at 70°C and add 69.264g (0.1248mol) of diacrylate diisocyanate and 0.1093g (0.0010mol) of a catalyst (triethylenediamine). Continue stirring for 6h to obtain an amino-terminated prepolymer①.

[0106] ⑵ Weigh 100g (0.1mol) of 1000g / mol polycarbonate diol and dehydrate it at 120℃ under vacuum for 2h, cool it to 70℃, introduce nitrogen and add 47.5494g (0.13mol) of diphenylmethane diisocyanate, and continue stirring for 3h to obtain an isocyanate-terminated prepolymer②.

[0107] ⑶ Add 39.3981 g (0.045 mol) of pure prepolymer ① to prepolymer ②, stir at 70°C for 6 hours to obtain isocyanate-terminated prepolymer ③.

[0108] (4) Finally, 12.5410 g (0.108 mol) of hydroxyethyl acrylate as a blocking agent was added, and infrared detection was performed until the characteristic peak of the isocyanate group completely disappeared, thereby obtaining an acrylate-blocked and acrylate-terminated polyurethane elastomer.

[0109] A free radical system anisotropic conductive material, the preparation formula and method are the same as those in Example 1.

[0110] Comparative Example 1

[0111] A method for preparing a polyurethane acrylate elastomer comprises the following steps:

[0112] ⑴ Weigh 40g (0.2496mol) of a small molecule diamine (1,8-naphthyridine-2,7-diamine) and dissolve it in toluene to obtain a diamine solution with a solid content of 10%. Add the solution into a three-necked flask, introduce nitrogen at 70°C, add 31.2324g (0.1248mol) of diphenylmethane diisocyanate and 0.1093g (0.0010mol) of a catalyst (triethylenediamine), and continue stirring for 6h to obtain an amino-terminated prepolymer①.

[0113] ⑵ Weigh 100g (0.1mol) of 1000g / mol polycarbonate diol and dehydrate it under vacuum at 120℃ for 2h, cool it to 70℃, introduce nitrogen and add 32.5388g (0.13mol) of diphenylmethane diisocyanate, and continue stirring for 3h to obtain an isocyanate-terminated prepolymer②.

[0114] ⑶ Add 8.5616 g (0.015 mol) of pure prepolymer ① to prepolymer ②, stir at 70°C for 6 hours to obtain isocyanate-terminated prepolymer ③.

[0115] (4) Finally, 4.1803 g (0.036 mol) of hydroxyethyl acrylate as a blocking agent was added, and infrared detection was performed until the characteristic peak of the isocyanate group completely disappeared, thereby obtaining an acrylate-blocked and acrylate-terminated polyurethane elastomer.

[0116] A free radical system anisotropic conductive material, the preparation formula and method are the same as those in Example 1.

[0117] Comparative Example 2

[0118] A method for preparing a polyurethane acrylate elastomer comprises the following steps:

[0119] ⑴ Weigh 100 g (0.1 mol) of 1000 g / mol polycarbonate diol and dehydrate it under vacuum at 120 ° C for 2 h, cool it to 70 ° C, pass nitrogen and add 30.0312 g (0.12 mol) of diphenylmethane diisocyanate, and continue stirring for 3 h to obtain an isocyanate-terminated prepolymer ②.

[0120] (2) Finally, 5.5738 g (0.048 mol) of hydroxyethyl acrylate as a capping agent was added, and infrared detection was performed until the characteristic peak of the isocyanate group completely disappeared to obtain an acrylate-capped polyurethane elastomer.

[0121] A free radical system anisotropic conductive material, the preparation formula and method are the same as those in Example 1.

[0122] The infrared spectra of the products of Examples 1 to 3 and Comparative Examples 1 to 2 are shown below: Figure 1 By infrared spectroscopy Figure 1 It can be seen that the 2265cm of Examples 1 to 3 and Comparative Examples 1 to 2 -1 ( Figure 1 There is no -NCO characteristic peak at position 1), indicating that a polyurethane acrylate elastomer is prepared, and the 1636 cm -1 ( Figure 1 There is an obvious double bond characteristic peak at the middle portion 2), and the double bond characteristic peak is stronger than that of comparative examples 1-2, indicating that the double bond density of embodiments 1-3 is higher than that of comparative examples 1-2.

[0123] The weight average molecular weights of the products of each stage of Examples 1 to 3 and Comparative Examples 1 to 2 are shown in the following table:

[0124] sample Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 <![CDATA[Molecular weight (prepolymer ②) M W > 21584 16355 12844 19823 41368 <![CDATA[Molecular weight (Prepolymer ③) M W > 39655 41580 41961 39887 / <![CDATA[Polyurethane acrylate elastomer M W > 40534 41648 42378 40889 42074

[0125] From the molecular weight test results, it can be seen that after the prepolymer ① was chain extended, the weight average molecular weight of Examples 1-3 increased, indicating that diisocyanate diacrylates with different double bond densities participated in the reaction in Examples 1-3. Comparative Example 1 was chain extended by 1,8-naphthyridine-2,7-diamine, and the weight average molecular weight increased, while Comparative Example 2 was not chain extended.

[0126] The conductive films prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested for mechanical properties, and the data are shown in the following table:

[0127] sample Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Film thickness(um) 25 25 25 25 25 Drop ball impact strength(g) 165 178 185 158 150 Film tensile strength (MPa) 180 195 205 160 151 Film elongation at break (%) 65 72 77 60 56

[0128] It can be seen from the mechanical properties test results that the conductive film drop ball impact strength, film tensile strength and film elongation at break of Examples 1-3 after curing are all higher than those of Comparative Examples 1-2.

[0129] Conductive films prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested for impedance. The test conditions were 140° C., 6 s, 4 MPa. The data are shown in the following table:

[0130] sample Example 1 Example 1 Example 1 Comparative Example 1 Comparative Example 2 Impedance (140℃, Ω) 0.87 0.74 0.65 1.15 1.23

[0131] From the impedance test results, it can be seen that the impedance of Examples 1-3 after curing is lower than that of Comparative Examples 1-2, indicating that the polyurethane acrylate elastomer helps to reduce the impedance of the conductive film.

[0132] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a polyurethane acrylate elastomer, characterized in that: The following steps are involved: (1) Dissolving a small molecular weight diamine in toluene to obtain a diamine solution, introducing nitrogen at 70° C. and adding a diisocyanate containing an acrylate functional group and a first catalyst, and continuously stirring for 6 to 12 hours to obtain an amino-terminated prepolymer①; The molar ratio of the small molecule diamine to the diisocyanate containing an acrylate functional group is 1.1 to 2.5:1; the first catalyst is 0.01 to 1% of the total mass of the system in step (1); (2) Dehydrating the oligomer diol at 100-120° C. under vacuum for 2 h, cooling to 70° C., introducing nitrogen, adding diisocyanate and a second catalyst, and continuously stirring for 3-12 h to obtain an isocyanate-terminated prepolymer ②; The molar ratio of diisocyanate to oligomer diol is 1.1 to 2.5:1; the second catalyst is 0.01 to 1% of the total mass of the system in step (2); (3) adding prepolymer ① to prepolymer ②, stirring at 70° C. for 3 to 6 hours, to obtain isocyanate-terminated prepolymer ③; the molar ratio of prepolymer ② to prepolymer ① is 1.1 to 2.5:1; (4) adding a hydroxy acrylate end-capping agent to the prepolymer ③, wherein the molar ratio of the hydroxy acrylate end-capping agent to the prepolymer ③ is 2.05 to 5.0:1; and using infrared detection until the characteristic peak of the isocyanate group completely disappears, thereby obtaining an acrylate-blocked, acrylate-terminated polyurethane acrylate elastomer.

2. The method for preparing a polyurethane acrylate elastomer according to claim 1, characterized in that: The small molecule diamine is naphthyridine diamine, and the structure is as follows: Among them, R8, R9, R 10 ,R 11 It is H or an integer representing the number of carbon atoms of 1 to 12.

3. The method for preparing a polyurethane acrylate elastomer according to claim 2, characterized in that: The small molecule diamine is 1,8-naphthyridine-2,7-diamine, and the structure is as follows:

4. The method for preparing a polyurethane acrylate elastomer according to claim 1, characterized in that: The structure of the diisocyanate containing acrylate functional groups is: or: in, It refers to aliphatic, aromatic, alicyclic or araliphatic; R1, R2, R3, R4, R5, R6, R7 are H or an integer representing the number of carbon atoms of 1 to 12.

5. The method for preparing a polyurethane acrylate elastomer according to claim 1, characterized in that: The diisocyanate is one or a combination of pure aromatic diisocyanate, pure aliphatic diisocyanate, aromatic aliphatic diisocyanate, and cycloaliphatic diisocyanate; The hydroxy acrylate end-capping agent is one or a combination of hydroxy acrylates, hydroxy diacrylates, and hydroxy triacrylates; The first catalyst and the second catalyst are one or a combination of organic bismuth, organic zinc, organic iron, and organic tertiary amine; The oligomer diol is one or a combination of polyoxypropylene diol, polyoxyethylene diol, adipic acid polyester diol, succinic acid polyester diol, isophthalic acid polyester diol, terephthalic acid polyester diol, polycarbonate diol, polycaprolactone diol, polytetramethylene glycol, polysiloxane diol, and polyether diol.

6. The method for preparing a polyurethane acrylate elastomer according to claim 5, characterized in that: The diisocyanates are 4-chloromethyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-m-phenylene diisocyanate, 3,3-dichlorobiphenyl-4,4-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, m-phenylene diisocyanate, m-phenylene diisocyanate, dimethyl biphenyl diisocyanate, polymethylene polyphenyl diisocyanate, and polymethylene diisocyanate. one or a combination of 1,4-cyclohexane diisocyanate, tetramethyl meta-xylylene diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexyl diisocyanate, methane cyclohexyl diisocyanate, cyclohexane dimethylene diisocyanate, norbornane diisocyanate, 1,6-hexamethylene diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, and L-lysine diisocyanate; The hydroxy acrylate end-capping agent is one or a combination of hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-propyl methacrylate, and pentaerythritol triacrylate; The first catalyst and the second catalyst are one or a combination of triethylenediamine, bis(dimethylaminoethyl) ether, N-ethylmorpholine, tetramethyldipropylenetriamine, iron octoate, bismuth carboxylate, and zinc cyclohexaneate.

7. The method for preparing a polyurethane acrylate elastomer according to claim 1, characterized in that: The structure of the prepolymer ① is as follows: The structure of the prepolymer ② is as follows: The structure of the prepolymer ③ is as follows: The polyurethane acrylate elastomer structure is as follows: ； Among them, m=6~30, n=1~10.

8. A polyurethane acrylate elastomer prepared by the method according to any one of claims 1 to 7.

9. A free radical system anisotropic conductive material, characterized in that: It includes a PET release film and a conductive film arranged on the release film; The conductive film comprises the following components by weight: The conductive film is prepared by the following method: adding reactive materials, the polyurethane acrylate elastomer according to claim 8, fillers, inhibitors, and conductive particles into a three-necked flask, using butanone as a solvent, preparing a 33% solid content resin solution, stirring at 80-100° C. until all components are evenly dispersed, then stopping heating and continuing stirring for 1 hour, cooling to room temperature, adding an initiator and stirring for 1 hour to obtain a coating liquid; the prepared coating liquid is scraped onto a PET release film, baked at 40-100° C. for 5-10 minutes, and dried to obtain a conductive film.

10. A free radical system anisotropic conductive material according to claim 9, characterized in that: The reactive material is acrylic acid, acrylate, vinyl ether, epoxy resin or polyester acrylate; the filler is silicon dioxide, acrylate microspheres, styrene microspheres, titanium dioxide, calcium carbonate or barium sulfate; the initiator is peroxide; the inhibitor is phenol, quinone, hindered phenol or hindered amine; the conductive particles are conductive microspheres or conductive metal powder.

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