Polyurethane-based UV anti-adhesive protective film and its preparation method

Abstract

The present invention discloses a preparation method of a polyurethane-based UV tack-reducing protective film. The preparation steps include: (1) Under a nitrogen protection atmosphere, in a reaction kettle, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, and hydroquinone are mixed, heated, isophorone diisocyanate is added, and the mixture is stirred at a constant temperature. Then, 1,4-butanediol is added to obtain an adhesive; (2) Hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, and maleic anhydride are mixed evenly, heated, triethylamine is added, and the mixture is stirred at a constant temperature. Then, epoxy soybean oil is added to obtain a modified acrylate monomer; (3) The adhesive is stirred, and then, under a stirring state, the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate, and a photoinitiator are added to the adhesive, and the mixture is stirred to obtain a UV tack-reducing adhesive. The adhesive is coated to obtain the UV tack-reducing protective film. The UV tack-reducing adhesive prepared by the method of the present invention has a good tack-reducing effect, is easy to peel off after tack reduction, and is convenient to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-adhesive protective films, and particularly relates to a polyurethane-based UV anti-adhesive protective film and a preparation method thereof. Background Art

[0002] With the continuous development of information technology and the semiconductor industry, the demand for various wafer-based devices is increasing day by day. The anti-adhesive film is one of the key materials for wafer processing. The anti-adhesive film, also known as anti-adhesive tape, is prepared by coating an anti-adhesive glue on substrates such as polyester film (PET), polyolefin film (PO), etc. In addition to the processing of semiconductor wafer materials, the cutting of ultra-thin glass and the acid treatment process of glass such as mobile phone screens all require the use of anti-adhesive films. The anti-adhesive film plays a role in fixing and protecting when processing easily damaged materials, preventing flying debris and breakage; after the processing is completed, in order to facilitate the picking of the processed parts, through the curing of the anti-adhesive effect, the adhesive force of the anti-adhesive film is greatly reduced, and the processed parts are separated from the substrate, and then the next step of processing is carried out. Summary of the Invention

[0003] Therefore, the present invention provides a preparation method of a polyurethane-based UV anti-adhesive protective film, and the preparation steps include:

[0004] (1) Under the protection of a nitrogen atmosphere, in a reaction kettle, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate and hydroquinone are mixed, and the mixture is heated in a water bath to 60 ± 3 °C. After reaching the temperature, keep it warm and stir. During the stirring process, isophorone diisocyanate is added to the mixture. After the addition is completed, keep it at a constant temperature of 60 ± 3 °C and stir for more than 2 h in a nitrogen atmosphere. Then, 1,4-butanediol is added. After the addition is completed, keep it at a constant temperature of 60 ± 3 °C and stir for more than 3 h in a nitrogen atmosphere to obtain an adhesive;

[0005] (2) Mix hydroxyethyl acrylate, methyltetrahydrophthalic anhydride and maleic anhydride evenly, then heat to 90 ± 2 °C and keep it warm. After reaching the temperature, stir for more than 10 min. Then, triethylamine is added under stirring. After the addition is completed, continue to stir at a constant temperature of 90 ± 2 °C for more than 30 min. Then, epoxy soybean oil is added. After the addition is completed, continue to stir at a constant temperature of 90 ± 2 °C for 50 - 60 min to obtain a modified acrylate monomer;

[0006] (3) Stir the adhesive, and then add the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and a photoinitiator to the adhesive under stirring. After the addition is completed, continue to stir for more than 30 min to obtain a UV anti-adhesive glue. Coating the UV anti-adhesive glue on the surface of a polyolefin film pretreated by corona, after the solvent has completely evaporated, the UV anti-adhesive protective film is obtained.

[0007] Further, in the step (1), the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate, and 1,4-butanediol are in parts by weight as follows: hydroxyl-terminated polybutadiene 10 parts, ethyl acetate 25 - 30 parts, 2-chloro-4,6-diphenyl-1,3,5-triazine 2 - 3 parts, ethylenediamine 0.4 - 0.8 parts; dibutyltin dilaurate 0.006 - 0.008 parts, hydroquinone 0.07 - 0.09 parts, isophorone diisocyanate 2 - 4 parts, 1,4-butanediol 1 - 2 parts.

[0008] Further, in the step (2), the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine, and epoxidized soybean oil are in parts by weight as follows: hydroxyethyl acrylate 100 parts, methyltetrahydrophthalic anhydride 35 - 40 parts, maleic anhydride 46 - 48 parts, triethylamine 2 - 3 parts, epoxidized soybean oil 100 - 110 parts.

[0009] Further, in the step (3), the mass ratio of the adhesive, the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate, and photoinitiator is adhesive:modified acrylate monomer:1-ethyl-3-methylimidazolium tetrafluoroborate:sodium octanesulfonate:photoinitiator = 100:15 - 18:6 - 7:0.8 - 1:2 - 4.

[0010] Further, in the step (3), the photoinitiator is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide.

[0011] Further, in the step (3), the wet film thickness of the coating is 50 - 60 μm.

[0012] The beneficial effects of the present invention are as follows: The UV tackifier prepared by the method of the present invention has good tack reduction effect. After tack reduction, it is easy to peel off, which is convenient for operation. And the adhesion performance before UV irradiation is good, which can well fix the wafer, and the use effect is excellent. The present invention modifies the hydroxyl-terminated polybutadiene with 2-chloro-4,6-diphenyl-1,3,5-triazine. When irradiated with UV light, under the action of the photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, it is more likely to undergo a crosslinking reaction, improve the degree of crosslinking, cause volume shrinkage of the adhesive layer, and greatly reduce the adhesion points. Then, by treating the acrylate monomer and introducing epoxy soybean oil groups onto the acrylate monomer, the functionality of the monomer is improved, the number of unsaturated C═C contained in the monomer is increased, and the crosslinking degree of the UV tackifier under UV irradiation is further improved, the crosslinking density is increased, and the peel strength after irradiation is significantly reduced. Finally, by introducing 1-ethyl-3-methylimidazolium tetrafluoroborate, it can promote the crosslinking of the monomer to a certain extent under UV irradiation conditions, and further improve the tack reduction effect. Detailed implementation mode

[0013] The following further illustrates the present invention in conjunction with examples.

[0014] Example 1

[0015] A preparation method of a polyurethane-based UV tackifier protective film, the preparation steps include:

[0016] (1) Under a nitrogen protection atmosphere, in a reaction kettle, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate and hydroquinone are mixed. The mixture is heated in a water bath to 60 ± 3 °C. After reaching the temperature, it is kept warm and stirred. During the stirring process, isophorone diisocyanate is added to the mixture. After the addition is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 2 h, and then 1,4-butanediol is added. After the addition is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 3 h to obtain an adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate and 1,4-butanediol are in parts by weight: hydroxyl-terminated polybutadiene 10 parts, ethyl acetate 25 parts, 2-chloro-4,6-diphenyl-1,3,5-triazine 2 parts, ethylenediamine 0.4 part; dibutyltin dilaurate 0.006 part, hydroquinone 0.07 part, isophorone diisocyanate 2 parts, 1,4-butanediol 1 part;

[0017] (2) Mix hydroxyethyl acrylate, methyltetrahydrophthalic anhydride and maleic anhydride evenly, then heat to 90 ± 2 °C for heat preservation. After reaching the temperature, stir for 10 min, then add triethylamine under stirring. After the feeding is completed, continue stirring at 90 ± 2 °C for 30 min, then add epoxidized soybean oil. After the feeding is completed, continue stirring at 90 ± 2 °C for 50 min to obtain the modified acrylate monomer; wherein the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine and epoxidized soybean oil are in parts by weight: 100 parts of hydroxyethyl acrylate, 35 parts of methyltetrahydrophthalic anhydride, 46 parts of maleic anhydride, 2 parts of triethylamine, and 100 parts of epoxidized soybean oil;

[0018] (3) Stir the adhesive, and then add the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator to the adhesive under stirring. The mass ratio of the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator added to the adhesive is adhesive: modified acrylate monomer: 1-ethyl-3-methylimidazolium tetrafluoroborate: sodium octanesulfonate: photoinitiator = 100:15:6:0.8:2; the photoinitiator is selected as (2,4,6-trimethylbenzoyl) diphenylphosphine oxide; after the feeding is completed, continue stirring for 30 min to obtain the UV tack-reducing adhesive. Coating the UV tack-reducing adhesive on the surface of the corona-pretreated polyolefin film, and the wet film thickness of the coating is 50 μm; after the solvent is completely evaporated, the UV tack-reducing protective film is obtained.

[0019] Example 2

[0020] A preparation method of a polyurethane-based UV tack-reducing protective film, and the preparation steps include:

[0021] (1) Under the protection of nitrogen atmosphere, in a reaction kettle, mix hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate and hydroquinone, and heat the mixture in a water bath to 60 ± 3 °C. After reaching the temperature, keep stirring. During the stirring process, add isophorone diisocyanate to the mixture. After the feeding is completed, keep stirring at 60 ± 3 °C in a nitrogen atmosphere for 2 h, then add 1,4-butanediol. After the feeding is completed, keep stirring at 60 ± 3 °C in a nitrogen atmosphere for 3 h to obtain the adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate and 1,4-butanediol are in parts by weight: 10 parts of hydroxyl-terminated polybutadiene, 27 parts of ethyl acetate, 2 parts of 2-chloro-4,6-diphenyl-1,3,5-triazine, 0.6 part of ethylenediamine; 0.007 part of dibutyltin dilaurate, 0.08 part of hydroquinone, 3 parts of isophorone diisocyanate, and 1 part of 1,4-butanediol;

[0022] (2) Mix hydroxyethyl acrylate, methyltetrahydrophthalic anhydride and maleic anhydride evenly, then heat to 90 ± 2 °C for heat preservation. After reaching the temperature, stir for 10 min, then add triethylamine under stirring. After the addition is completed, continue stirring at 90 ± 2 °C for 30 min, then add epoxidized soybean oil. After the addition is completed, continue stirring at 90 ± 2 °C for 50 min to obtain a modified acrylate monomer; wherein the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine and epoxidized soybean oil are in parts by weight as follows: 100 parts of hydroxyethyl acrylate, 38 parts of methyltetrahydrophthalic anhydride, 47 parts of maleic anhydride, 2 parts of triethylamine, and 100 parts of epoxidized soybean oil;

[0023] (3) Stir the adhesive, and then add the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator to the adhesive under stirring. The mass ratio of the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator added to the adhesive is adhesive:modified acrylate monomer:1-ethyl-3-methylimidazolium tetrafluoroborate:sodium octanesulfonate:photoinitiator = 100:16:6:0.9:3; The photoinitiator is selected as (2,4,6-trimethylbenzoyl) diphenylphosphine oxide; after the addition is completed, continue stirring for 30 min to obtain a UV tack-reducing adhesive. Coat the UV tack-reducing adhesive on the surface of a corona-pretreated polyolefin film, and the wet film thickness of the coating is 50 μm; after the solvent has completely evaporated, obtain the UV tack-reducing protective film.

[0024] Example 3

[0025] A preparation method of a polyurethane-based UV tack-reducing protective film, the preparation steps include:

[0026] (1) Under a nitrogen protection atmosphere, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, and hydroquinone were mixed in a reaction kettle. The mixture was heated in a water bath to 60 ± 3 °C. After reaching the temperature, it was kept warm and stirred. During the stirring process, isophorone diisocyanate was added to the mixture. After the feeding was completed, it was stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 2 h. Then, 1,4-butanediol was added. After the feeding was completed, it was stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 3 h to obtain an adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate, and 1,4-butanediol are in parts by weight as follows: hydroxyl-terminated polybutadiene 10 parts, ethyl acetate 28 parts, 2-chloro-4,6-diphenyl-1,3,5-triazine 3 parts, ethylenediamine 0.6 part; dibutyltin dilaurate 0.007 part, hydroquinone 0.08 part, isophorone diisocyanate 3 parts, 1,4-butanediol 2 parts;

[0027] (2) Hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, and maleic anhydride were mixed evenly, and then heated to 90 ± 2 °C and kept warm. After reaching the temperature, it was stirred for 10 min. Then, triethylamine was added under stirring. After the feeding was completed, it was continuously stirred at a constant temperature of 90 ± 2 °C for 30 min. Then, epoxidized soybean oil was added. After the feeding was completed, it was continuously stirred at a constant temperature of 90 ± 2 °C for 50 min to obtain a modified acrylate monomer; wherein the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine, and epoxidized soybean oil are in parts by weight as follows: hydroxyethyl acrylate 100 parts, methyltetrahydrophthalic anhydride 39 parts, maleic anhydride 47 parts, triethylamine 3 parts, epoxidized soybean oil 110 parts;

[0028] (3) The adhesive was stirred, and then the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate, and photoinitiator were added to the adhesive under stirring. The mass ratio of the adhesive, the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate, and photoinitiator added to the adhesive is adhesive: modified acrylate monomer: 1-ethyl-3-methylimidazolium tetrafluoroborate: sodium octanesulfonate: photoinitiator = 100:17:7:0.9:3; the photoinitiator selected is (2,4,6-trimethylbenzoyl) diphenylphosphine oxide; after the feeding was completed, it was continuously stirred for 30 min to obtain a UV tack-reducing adhesive. The UV tack-reducing adhesive was coated on the surface of a corona-pretreated polyolefin film, and the wet film thickness of the coating was 50 μm; after the solvent was completely evaporated, the UV tack-reducing protective film was obtained.

[0029] Example 4

[0030] A preparation method of a polyurethane-based UV tack-reducing protective film, the preparation steps include:

[0031] (1) Under a nitrogen protection atmosphere, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate and hydroquinone are mixed in a reaction kettle. The mixture is heated in a water bath to 60 ± 3 °C. After reaching the temperature, it is kept warm and stirred. During the stirring process, isophorone diisocyanate is added to the mixture. After the feeding is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 2 h. Then, 1,4-butanediol is added. After the feeding is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 3 h to obtain an adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate and 1,4-butanediol are in parts by weight: 10 parts of hydroxyl-terminated polybutadiene, 30 parts of ethyl acetate, 3 parts of 2-chloro-4,6-diphenyl-1,3,5-triazine, 0.8 part of ethylenediamine; 0.008 part of dibutyltin dilaurate, 0.09 part of hydroquinone, 4 parts of isophorone diisocyanate, 2 parts of 1,4-butanediol;

[0032] (2) Hydroxyethyl acrylate, methyltetrahydrophthalic anhydride and maleic anhydride are mixed evenly, and then heated to 90 ± 2 °C for heat preservation. After reaching the temperature, it is stirred for 10 min. Then, triethylamine is added under stirring. After the feeding is completed, it is continuously stirred at a constant temperature of 90 ± 2 °C for 30 min. Then, epoxy soybean oil is added. After the feeding is completed, it is continuously stirred at a constant temperature of 90 ± 2 °C for 50 min to obtain a modified acrylate monomer; wherein the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine and epoxy soybean oil are in parts by weight: 100 parts of hydroxyethyl acrylate, 40 parts of methyltetrahydrophthalic anhydride, 48 parts of maleic anhydride, 3 parts of triethylamine, 110 parts of epoxy soybean oil;

[0033] (3) Stir the adhesive, and then add the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator to the adhesive under stirring. The mass ratio of the adhesive to the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator added to the adhesive is adhesive:modified acrylate monomer:1-ethyl-3-methylimidazolium tetrafluoroborate:sodium octanesulfonate:photoinitiator = 100:18:7:1:4; The photoinitiator selected is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide; After the feeding is completed, it is continuously stirred for 30 min to obtain a UV pressure-sensitive adhesive reducing agent. The UV pressure-sensitive adhesive reducing agent is coated on the surface of a polyolefin film pretreated by corona. The wet film thickness of the coating is 50 μm; After the solvent has completely evaporated, the UV pressure-sensitive protective film is obtained.

[0034] Comparative Example 1

[0035] A preparation method of a polyurethane-based UV adhesion-reducing protective film for comparison, the preparation steps include:

[0036] (1) Under a nitrogen protection atmosphere, in a reaction kettle, hydroxyl-terminated polybutadiene, ethyl acetate, ethylenediamine, dibutyltin dilaurate and hydroquinone are mixed, and the mixture is heated in a water bath to 60 ± 3 °C. After reaching the temperature, keep stirring while adding isophorone diisocyanate to the mixture. After the feeding is completed, keep stirring at 60 ± 3 °C in a nitrogen atmosphere for 2 h, then add 1,4-butanediol. After the feeding is completed, keep stirring at 60 ± 3 °C in a nitrogen atmosphere for 3 h to obtain an adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate and 1,4-butanediol are in parts by weight: hydroxyl-terminated polybutadiene 10 parts, ethyl acetate 28 parts, ethylenediamine 0.6 part; dibutyltin dilaurate 0.007 part, hydroquinone 0.08 part, isophorone diisocyanate 3 parts, 1,4-butanediol 2 parts;

[0037] (2) Mix hydroxyethyl acrylate, methyltetrahydrophthalic anhydride and maleic anhydride evenly, then heat to 90 ± 2 °C and keep warm. After reaching the temperature, stir for 10 min, then add triethylamine under stirring. After the feeding is completed, continue to stir at 90 ± 2 °C for 30 min, then add epoxidized soybean oil. After the feeding is completed, continue to stir at 90 ± 2 °C for 50 min to obtain a modified acrylate monomer; wherein the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine and epoxidized soybean oil are in parts by weight: hydroxyethyl acrylate 100 parts, methyltetrahydrophthalic anhydride 39 parts, maleic anhydride 47 parts, triethylamine 3 parts, epoxidized soybean oil 110 parts;

[0038] (3) Stir the adhesive, then add the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octane sulfonate and photoinitiator to the adhesive under stirring. The mass ratio of the adhesive to the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octane sulfonate and photoinitiator in the adhesive is adhesive: modified acrylate monomer: 1-ethyl-3-methylimidazolium tetrafluoroborate: sodium octane sulfonate: photoinitiator = 100:17:7:0.9:3; The photoinitiator is selected as (2,4,6-trimethylbenzoyl) diphenylphosphine oxide; after the feeding is completed, continue to stir for 30 min to obtain a UV adhesion-reducing adhesive. Coat the UV adhesion-reducing adhesive on the surface of a polyolefin film pretreated by corona, and the wet film thickness of the coating is 50 μm; after the solvent has completely evaporated, obtain the UV adhesion-reducing protective film of this comparative example.

[0039] Comparative Example 2

[0040] A preparation method of a polyurethane-based UV adhesion-reducing protective film for comparison, the preparation steps include:

[0041] (1) Under a nitrogen protection atmosphere, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate and hydroquinone are mixed in a reaction kettle. The mixture is heated in a water bath to 60 ± 3 °C, and after reaching the temperature, it is kept warm and stirred. During the stirring process, isophorone diisocyanate is added to the mixture. After the feeding is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 2 h, and then 1,4-butanediol is added. After the feeding is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 3 h to obtain an adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate and 1,4-butanediol are in parts by weight: 10 parts of hydroxyl-terminated polybutadiene, 28 parts of ethyl acetate, 3 parts of 2-chloro-4,6-diphenyl-1,3,5-triazine, 0.6 part of ethylenediamine; 0.007 part of dibutyltin dilaurate, 0.08 part of hydroquinone, 3 parts of isophorone diisocyanate, 2 parts of 1,4-butanediol;

[0042] (2) Hydroxyethyl acrylate, methyltetrahydrophthalic anhydride and maleic anhydride are mixed evenly, and then heated to 90 ± 2 °C for heat preservation. After reaching the temperature, it is stirred for 10 min, and then triethylamine is added under stirring. After the feeding is completed, it is continuously stirred at a constant temperature of 90 ± 2 °C for 80 min to obtain the modified acrylate monomer of this comparative example; wherein the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride and triethylamine are in parts by weight: 100 parts of hydroxyethyl acrylate, 39 parts of methyltetrahydrophthalic anhydride, 47 parts of maleic anhydride, 3 parts of triethylamine;

[0043] (3) Stir the adhesive, and then add the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator to the adhesive under stirring. The mass ratio of the adhesive to the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and photoinitiator in the adhesive is adhesive:modified acrylate monomer:1-ethyl-3-methylimidazolium tetrafluoroborate:sodium octanesulfonate:photoinitiator = 100:17:7:0.9:3; The photoinitiator is selected as (2,4,6-trimethylbenzoyl) diphenylphosphine oxide; after the feeding is completed, it is continuously stirred for 30 min to obtain a UV pressure-sensitive adhesive-reducing adhesive. The UV pressure-sensitive adhesive-reducing adhesive is coated on the surface of a polyolefin film pretreated by corona, and the wet film thickness of the coating is 50 μm; after the solvent has completely evaporated, the UV pressure-sensitive adhesive-reducing protective film of this comparative example is obtained.

[0044] Comparative Example 3

[0045] A preparation method of a polyurethane-based UV pressure-sensitive adhesive-reducing protective film for comparison, the preparation steps include:

[0046] (1) Under a nitrogen protection atmosphere, in a reaction kettle, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, and hydroquinone are mixed. The mixture is heated in a water bath to 60 ± 3 °C. After reaching the temperature, it is kept warm and stirred. During the stirring process, isophorone diisocyanate is added to the mixture. After the addition is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 2 h. Then, 1,4-butanediol is added. After the addition is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for 3 h to obtain an adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate, and 1,4-butanediol are in parts by weight as follows: hydroxyl-terminated polybutadiene 10 parts, ethyl acetate 28 parts, 2-chloro-4,6-diphenyl-1,3,5-triazine 3 parts, ethylenediamine 0.6 part; dibutyltin dilaurate 0.007 part, hydroquinone 0.08 part, isophorone diisocyanate 3 parts, 1,4-butanediol 2 parts;

[0047] (2) Hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, and maleic anhydride are mixed evenly, and then heated to 90 ± 2 °C for heat preservation. After reaching the temperature, it is stirred for 10 min. Then, triethylamine is added under stirring. After the addition is completed, it is continuously stirred at a constant temperature of 90 ± 2 °C for 30 min. Then, epoxidized soybean oil is added. After the addition is completed, it is continuously stirred at a constant temperature of 90 ± 2 °C for 50 min to obtain a modified acrylate monomer; wherein the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine, and epoxidized soybean oil are in parts by weight as follows: hydroxyethyl acrylate 100 parts, methyltetrahydrophthalic anhydride 39 parts, maleic anhydride 47 parts, triethylamine 3 parts, epoxidized soybean oil 110 parts;

[0048] (3) Stir the adhesive, and then add the modified acrylate monomer, sodium octane sulfonate, and photoinitiator to the adhesive under stirring. The mass ratio of the adhesive, the modified acrylate monomer, sodium octane sulfonate, and the photoinitiator added to the adhesive is adhesive: modified acrylate monomer: sodium octane sulfonate: photoinitiator = 100:17:0.9:3; The photoinitiator selected is (2,4,6-trimethylbenzoyl) diphenylphosphine oxide; After the addition is completed, it is continuously stirred for 30 min to obtain a UV pressure-sensitive adhesive reducing agent. The UV pressure-sensitive adhesive reducing agent is coated on the surface of a polyolefin film pretreated by corona discharge, and the wet film thickness of the coating is 50 μm; After the solvent has completely evaporated, the UV pressure-sensitive adhesive protective film of this comparative example is obtained.

[0049] Example 5

[0050] The 180° peel strength values of the UV tack-reducing protective films prepared by the methods of the above-mentioned examples and comparative examples before and after UV irradiation were respectively tested according to the requirements of Standard GB / T 2792-2014. The width of the test specimen was 25 mm, the length was 200 mm, and the tensile rate was set at 300 mm / min. The results are shown in Table 1.

[0051] Table 1

[0052] Experimental group 180° peel strength (N / 25 mm) before UV light irradiation 180° peel strength (N / 25 mm) after UV light irradiation Example 1 18.8 0.26 Example 2 19.1 0.23 Example 3 19.2 0.21 Example 4 19.0 0.23 Comparative example 1 18.1 0.74 Comparative example 2 18.3 1.08 Comparative example 3 18.6 0.95

[0053] As can be seen from Table 1, the UV tack-reducing adhesive prepared by the method of the present invention has a good tack-reducing effect. After tack reduction, it is easy to peel off, which is convenient for operation. Moreover, the adhesion performance before UV irradiation is good, which can well realize the fixation of the wafer, and the use effect is excellent. In the present invention, 2-chloro-4,6-diphenyl-1,3,5-triazine is used to modify terminal hydroxyl polybutadiene. When irradiated with UV light, it is more likely to undergo a crosslinking reaction under the action of a photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, improving the degree of crosslinking, causing volume shrinkage of the adhesive layer, and greatly reducing the adhesion points. By further treating acrylate monomers and introducing epoxy soybean oil groups onto the acrylate monomers, the functionality of the monomers is increased, the number of unsaturated C═C contained in the monomers is increased, and the crosslinking degree of the tack-reducing adhesive under UV irradiation is further improved, and the crosslinking density is increased, resulting in a significant decrease in the peel strength after irradiation. Finally, by introducing 1-ethyl-3-methylimidazolium tetrafluoroborate, the crosslinking of monomers under UV irradiation conditions can be promoted to a certain extent, further improving the tack-reducing effect.

[0054] The technical solutions provided by the present invention have been introduced in detail above. For those of ordinary skill in the art, according to the ideas of the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A preparation method of a polyurethane-based UV tack-reducing protective film, characterized in that, The preparation steps include: (1) Under the protection of nitrogen atmosphere, in a reaction kettle, hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate and hydroquinone are mixed. The mixture is heated in a water bath to 60 ± 3 °C. After reaching the temperature, it is kept warm and stirred. During the stirring process, isophorone diisocyanate is added to the mixture. After the feeding is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for more than 2 h. Then, 1,4-butanediol is added. After the feeding is completed, it is stirred at a constant temperature of 60 ± 3 °C in a nitrogen atmosphere for more than 3 h to obtain an adhesive; wherein the hydroxyl-terminated polybutadiene, ethyl acetate, 2-chloro-4,6-diphenyl-1,3,5-triazine, ethylenediamine, dibutyltin dilaurate, hydroquinone, isophorone diisocyanate and 1,4-butanediol are in parts by weight: 10 parts of hydroxyl-terminated polybutadiene, 25 - 30 parts of ethyl acetate, 2 - 3 parts of 2-chloro-4,6-diphenyl-1,3,5-triazine, 0.4 - 0.8 part of ethylenediamine; 0.006 - 0.008 part of dibutyltin dilaurate, 0.07 - 0.09 part of hydroquinone, 2 - 4 parts of isophorone diisocyanate, 1 - 2 parts of 1,4-butanediol; (2) Hydroxyethyl acrylate, methyltetrahydrophthalic anhydride and maleic anhydride are mixed evenly, and then heated to 90 ± 2 °C for heat preservation. After reaching the temperature, it is stirred for more than 10 min. Then, triethylamine is added under stirring. After the feeding is completed, it is continuously stirred at a constant temperature of 90 ± 2 °C for more than 30 min. Then, epoxidized soybean oil is added. After the feeding is completed, it is continuously stirred at a constant temperature of 90 ± 2 °C for 50 - 60 min to obtain a modified acrylate monomer; (3) The adhesive is stirred, and then the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and a photoinitiator are added to the adhesive under stirring. After the feeding is completed, it is continuously stirred for more than 30 min to obtain a UV tack-reducing adhesive. The UV tack-reducing adhesive is coated on the surface of a polyolefin film pretreated by corona. After the solvent has completely evaporated, the UV tack-reducing protective film is obtained.

2. The preparation method of a polyurethane-based UV tack-reducing protective film according to claim 1, characterized in that, In the step (2), the hydroxyethyl acrylate, methyltetrahydrophthalic anhydride, maleic anhydride, triethylamine and epoxidized soybean oil are in parts by weight: 100 parts of hydroxyethyl acrylate, 35 - 40 parts of methyltetrahydrophthalic anhydride, 46 - 48 parts of maleic anhydride, 2 - 3 parts of triethylamine, 100 - 110 parts of epoxidized soybean oil.

3. The preparation method of a polyurethane-based UV adhesion-reducing protective film according to claim 1, characterized in that, In the step (3), the mass ratio of the adhesive to the modified acrylate monomer, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium octanesulfonate and the photoinitiator added to the adhesive is adhesive:modified acrylate monomer:1-ethyl-3-methylimidazolium tetrafluoroborate:sodium octanesulfonate:photoinitiator = 100:15 - 18:6 - 7:0.8 - 1:2 - 4.

4. The preparation method of a polyurethane-based UV tack-reducing protective film according to claim 1, wherein, In the step (3), the photoinitiator is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide.

5. The preparation method of a polyurethane-based UV tack-reducing protective film according to claim 1, characterized in that, In the step (3), the wet film thickness of the coating is 50 - 60 μm.