Preparation method of acid-resistant viscosity-reducing adhesive tape

Abstract

The invention relates to a viscosity-reducing adhesive, and discloses a preparation method of an acid-resistant viscosity-reducing adhesive tape, which comprises the following steps: reacting polytetrahydrofuran ether glycol, hydroxyl-terminated allyloxy polyester, an isocyanate monomer, dibutyltin dilaurate, 1, 4-butanediol and the like, and then adding an active diluent and a photoinitiator to obtain the acid-resistant viscosity-reducing adhesive tape. The side chain of polyurethane contains alkenyl with smaller steric hindrance, the alkenyl and the reactive diluent are subjected to better photocuring cross-linking reaction, and after photocuring, the volume of a cured adhesive film of the viscosity-reducing adhesive is shrunk, so that the adhesive property and the peel strength are reduced, and the viscosity-reducing adhesive shows excellent viscosity-reducing property and easy-to-peel effect. Meanwhile, the acid resistance of the polyurethane adhesive is improved, and high peel strength is still kept after acid leaching.

Description

Technical Field

[0001] The invention relates to a viscosity-reducing adhesive, in particular to a method for preparing an acid-resistant viscosity-reducing adhesive tape. Background Art

[0002] Polyurethane has good bonding properties, high flexibility, and high mechanical strength, and can be cured by various methods such as thermal curing and light curing. It is widely used in the fields of viscosity-reducing adhesives, conductive adhesives, and three-proof adhesives. The current polyurethane UV viscosity-reducing adhesive has problems such as a low drop in peel strength after light exposure and poor viscosity-reducing effect. In addition, the polyurethane adhesive prepared with polyester polyol as raw material has poor hydrolysis resistance and acid decomposition resistance. The patent with announcement number CN113736420B discloses a polyurethane-type UV viscosity-reducing adhesive and a preparation method thereof. Terminal hydroxyitaconic acid-aliphatic diol copolyester is introduced into the UV viscosity-reducing adhesive. The double bonds on the side chains have high reactivity. Under UV irradiation, the double bonds undergo a cross-linking reaction, and the viscosity-reducing effect is significant. However, the patent does not improve the acid resistance of the polyurethane adhesive, and its practical application is limited. Summary of the Invention

[0003] The invention solves the problem of poor viscosity reduction of polyurethane glue and improves the acid resistance of polyurethane glue.

[0004] The technical solution of the present invention: a method for preparing an acid-resistant adhesive tape: S1. Add N,N-dimethylformamide, 2,2-dibutylpropane-1,3-diol, triethylamine, and 5-allyloxyisophthaloyl chloride to a reaction vessel, stir for reaction, and filter. Add the filtrate to water, stir, and filter. Wash the product with ethanol and dry to obtain a hydroxy-terminated allyloxy polyester. The reaction formula is: .

[0005] S2. Add polytetramethylene ether glycol, terminal hydroxy allyloxy polyester, isocyanate monomer, and dibutyltin dilaurate into a reaction container, and carry out polymerization reaction in a nitrogen atmosphere; add 1,4-butanediol and acetone, carry out chain extension reaction, add active diluent, dry and remove acetone, add photoinitiator, stir and mix to obtain acid-resistant viscosity-reducing adhesive; finally, coat the acid-resistant viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing adhesive tape.

[0006] Preferably, the molar ratio of 2,2-dibutylpropane-1,3-diol, triethylamine, and 5-allyloxyisophthaloyl chloride in S1 is (1.2-1.3):(2-2.2):1.

[0007] Preferably, the 2,2-dibutylpropane-1,3-diol in S1 is 2,2-dibutylpropane-1,3-diol, 2,2-dibutylpropane-1,3-diol or 2-methyl-2-propyl-1,3-propanediol.

[0008] Preferably, the reaction in S1 is first carried out at 0-5°C for 40-60 min, and then at 20-30°C for 4-6 h.

[0009] Preferably, the mass ratio of polytetramethylene ether diol, terminal hydroxyl allyloxy polyester, isocyanate monomer, reactive diluent, and photoinitiator in S2 is (110-160): (22-40): (45-66): (9-11): (28-36): (6.2-8.5).

[0010] Preferably, the isocyanate monomer in S2 is isophorone diisocyanate or toluene-2,4-diisocyanate.

[0011] Preferably, the polymerization reaction in S2 is carried out at 70-80° C. for 3-4 hours.

[0012] Preferably, the chain extension reaction in S2 is carried out at 40-50° C. for 60-90 min.

[0013] Preferably, the reactive diluent in S2 is tripropylene glycol diacrylate or dipropylene glycol diacrylate.

[0014] Preferably, the photoinitiator is TPO.

[0015] Preferably, the preparation method of 5-allyloxyisophthaloyl chloride is as follows: add dichloromethane, N,N-dimethylformamide, 5-allyloxyisophthalic acid and thionyl chloride in a molar ratio of 1:(6-8) to a reaction vessel, heat to 40-50°C, reflux under condensation for 4-6 hours, distill under reduced pressure, and dry to obtain 5-allyloxyisophthaloyl chloride. The reaction formula is: .

[0016] The beneficial technical effects of the present invention include: 2,2-dibutylpropane-1,3-diol and 5-allyloxyisophthaloyl chloride are polymerized to obtain a hydroxy-terminated allyloxy polyester, which is then reacted with polytetramethylene ether glycol, an isocyanate monomer, a chain extender, and the like to obtain an alkenyl-containing polyurethane. Finally, the polyurethane is compounded with a reactive diluent and a photoinitiator to obtain a viscosity-reducing adhesive. By containing less sterically hindered alkenyl groups in the side chains of the polyurethane, a better photocuring cross-linking reaction with the reactive diluent occurs. After photocuring, the cured adhesive film of the viscosity-reducing adhesive shrinks in volume, and wrinkles and unevenness develop on the surface of the adhesive layer, reducing the flatness of the adhesive layer and the contact area between the adhesive layer and the silicon wafer, thereby reducing the bonding performance and peel strength, exhibiting excellent viscosity-reducing properties and easy peeling effects.

[0017] The 2,2-dibutylpropane-1,3-diol of the present invention contains a butyl structure with relatively large steric hindrance and hydrophobicity, which is introduced into the terminal hydroxyl polyester and the polyurethane molecular chain thereof, thereby reducing the contact between water molecules and hydrochloric acid and the polyester molecular chain, thereby inhibiting the acidolysis of the polyester and polyurethane molecular chains, improving the acid resistance of the polyurethane adhesive, and still maintaining a high peel strength after acid immersion. DETAILED DESCRIPTION

[0018] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as limiting the present invention.

[0019] The following polytetramethylene ether glycol has a molecular weight of 2000 and was dried to remove water before use.

[0020] Example 1 (1) Add 350 mL of dichloromethane, 0.8 mL of catalyst N,N-dimethylformamide, 40 mmol of 5-allyloxyisophthalic acid (CAS No. 88194-15-4), and 240 mmol of thionyl chloride to a reaction vessel, heat to 50 °C, condense and reflux for 4 h, distill under reduced pressure, and dry to obtain 5-allyloxyisophthaloyl chloride.

[0021] (2) Add 50 mL of N,N-dimethylformamide, 60 mmol of 2,2-dibutylpropane-1,3-diol (CAS No. 24765-57-9), 100 mmol of triethylamine, and 50 mmol of 5-allyloxyisophthaloyl chloride to the reaction vessel, stir and react at 0°C for 60 minutes, then at 25°C for 6 hours, filter, add the filtrate to water, stir and filter, wash the product with ethanol, and dry to obtain terminal hydroxy allyloxy polyester.

[0022] (3) Add 160g of polytetramethylene glycol, 22g of terminal hydroxyl allyloxy polyester, 66g of isophorone diisocyanate, and 0.32g of dibutyltin dilaurate to the reaction container, heat to 75°C in a nitrogen atmosphere, and react for 4h; add 9.6g of 1,4-butanediol and 200mL of acetone, reduce the temperature to 40°C, react for 90min, add 30g of dipropylene glycol diacrylate, dry to remove acetone, add 7.7g of photoinitiator TPO, stir and mix to obtain an acid-resistant viscosity-reducing adhesive; finally, coat the acid-resistant viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing adhesive tape.

[0023] Example 2 (1) Add 400 mL of dichloromethane, 0.5 mL of catalyst N,N-dimethylformamide, 40 mmol of 5-allyloxyisophthalic acid, and 320 mmol of thionyl chloride to a reaction vessel, heat to 40 °C, condense and reflux for 6 h, distill under reduced pressure, and dry to obtain 5-allyloxyisophthaloyl chloride.

[0024] (2) Add 60 mL of N,N-dimethylformamide, 60 mmol of 2,2-dibutylpropane-1,3-diol, 110 mmol of triethylamine, and 50 mmol of 5-allyloxyisophthaloyl chloride to the reaction vessel, stir and react at 0°C for 60 min, then at 20°C for 6 h, filter, add the filtrate to water, stir and filter, wash the product with ethanol, and dry to obtain terminal hydroxy allyloxy polyester.

[0025] (3) Add 145g of polytetramethylene glycol, 28g of terminal hydroxyl allyloxy polyester, 48g of toluene-2,4-diisocyanate, and 0.36g of dibutyltin dilaurate to the reaction container, heat to 80°C in a nitrogen atmosphere, and react for 3h; add 10.3g of 1,4-butanediol and 250mL of acetone, reduce the temperature to 50°C, react for 60min, add 28g of dipropylene glycol diacrylate, dry to remove acetone, add 6.2g of photoinitiator TPO, stir and mix to obtain an acid-resistant viscosity-reducing adhesive; finally, coat the acid-resistant viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing adhesive tape.

[0026] Example 3 (1) Add 60 mL of N,N-dimethylformamide, 65 mmol of 2,2-dibutylpropane-1,3-diol, 110 mmol of triethylamine, and 50 mmol of 5-allyloxyisophthaloyl chloride (prepared in Example 1) into a reaction vessel, stir and react at 0°C for 60 min, then at 30°C for 4 h, filter, add the filtrate to water, stir and filter, wash the product with ethanol, and dry to obtain a terminal hydroxy-allyloxy polyester.

[0027] (2) Add 128g of polytetramethylene glycol, 34g of terminal hydroxyl allyloxy polyester, 45g of toluene-2,4-diisocyanate, and 0.36g of dibutyltin dilaurate to the reaction container, heat to 80°C in a nitrogen atmosphere, and react for 3h; add 11g of 1,4-butanediol and 300mL of acetone, reduce the temperature to 45°C, react for 90min, add 33g of tripropylene glycol diacrylate, dry to remove acetone, add 8.5g of photoinitiator TPO, stir and mix to obtain an acid-resistant viscosity-reducing adhesive; finally, coat the acid-resistant viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing adhesive tape.

[0028] Example 4 (1) Add 50 mL of N,N-dimethylformamide, 60 mmol of 2,2-dibutylpropane-1,3-diol, 106 mmol of triethylamine, and 50 mmol of 5-allyloxyisophthaloyl chloride (prepared in Example 1) into a reaction vessel, stir and react at 5°C for 40 min, then at 25°C for 6 h, filter, add the filtrate to water, stir and filter, wash the product with ethanol, and dry to obtain a terminal hydroxy-allyloxy polyester.

[0029] (2) Add 110 g of polytetramethylene ether glycol, 40 g of terminal hydroxyl allyloxy polyester, 64 g of isophorone diisocyanate, and 0.33 g of dibutyltin dilaurate to the reaction container, heat to 70 ° C in a nitrogen atmosphere, and react for 4 hours; add 9 g of 1,4-butanediol and 300 mL of acetone, reduce the temperature to 40 ° C, and react for 90 minutes; add 36 g of tripropylene glycol diacrylate, dry to remove acetone, add 7.1 g of photoinitiator TPO, stir and mix to obtain an acid-resistant viscosity-reducing adhesive; finally, coat the acid-resistant viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing adhesive tape.

[0030] Comparative Example 1: The main difference between this comparative example and Example 1 is that isophthaloyl chloride (CAS No. 99-63-8) is used instead of 5-allyloxyisophthaloyl chloride when preparing the hydroxyl-terminated polyester.

[0031] (1) Add 50 mL of N,N-dimethylformamide, 60 mmol of 2,2-dibutylpropane-1,3-diol, 100 mmol of triethylamine, and 50 mmol of isophthaloyl chloride to a reaction vessel, stir and react at 0°C for 60 min, then at 25°C for 6 h, filter, add the filtrate to water, stir and filter, wash the product with ethanol, and dry to obtain a hydroxyl-terminated polyester.

[0032] (2) Add 160g of polytetramethylene glycol, 22g of terminal hydroxy polyester, 66g of isophorone diisocyanate, and 0.32g of dibutyltin dilaurate to the reaction container, heat to 75°C in a nitrogen atmosphere, and react for 4h; add 9.6g of 1,4-butanediol and 200mL of acetone, reduce the temperature to 40°C, react for 90min, add 30g of dipropylene glycol diacrylate, dry to remove acetone, add 7.7g of photoinitiator TPO, stir and mix to obtain a viscosity-reducing adhesive; finally, coat the viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing tape.

[0033] Comparative Example 2: The main difference between this comparative example and Example 1 is that, when preparing the hydroxyl-terminated polyester, butylenedichloride (CAS No. 543-20-4) is used instead of 5-allyloxyisophthaloyl chloride.

[0034] (1) Add 50 mL of N,N-dimethylformamide, 60 mmol of 2,2-dibutylpropane-1,3-diol, 100 mmol of triethylamine, and 50 mmol of butenedioyl chloride to a reaction vessel, stir and react at 0°C for 60 min, then at 25°C for 6 h, filter, add the filtrate to water, stir and filter, wash the product with ethanol, and dry to obtain a hydroxyl-terminated polyester.

[0035] (2) Add 160g of polytetramethylene glycol, 22g of terminal hydroxy polyester, 66g of isophorone diisocyanate, and 0.32g of dibutyltin dilaurate to the reaction container, heat to 75°C in a nitrogen atmosphere, and react for 4h; add 9.6g of 1,4-butanediol and 200mL of acetone, reduce the temperature to 40°C, react for 90min, add 30g of dipropylene glycol diacrylate, dry to remove acetone, add 7.7g of photoinitiator TPO, stir and mix to obtain a viscosity-reducing adhesive; finally, coat the viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing tape.

[0036] Comparative Example 3: The main difference between this comparative example and Example 1 is that 1,3-propylene glycol is used instead of 2,2-dibutylpropane-1,3-diol in preparing the hydroxy-terminated allyloxy polyester.

[0037] (1) Add 50 mL of N,N-dimethylformamide, 60 mmol of 1,3-propylene glycol, 100 mmol of triethylamine, and 50 mmol of 5-allyloxyisophthaloyl chloride to a reaction vessel, stir and react at 0°C for 60 min, then at 25°C for 6 h, filter, add the filtrate to water, stir and filter, wash the product with ethanol, and dry to obtain terminal hydroxy allyloxy polyester.

[0038] (2) Add 160g of polytetramethylene glycol, 22g of terminal hydroxyl allyloxy polyester, 66g of isophorone diisocyanate, and 0.32g of dibutyltin dilaurate to the reaction container, heat to 75°C in a nitrogen atmosphere, and react for 4h; add 9.6g of 1,4-butanediol and 200mL of acetone, reduce the temperature to 40°C, react for 90min, add 30g of dipropylene glycol diacrylate, dry to remove acetone, add 7.7g of photoinitiator TPO, stir and mix to obtain a viscosity-reducing adhesive; finally, coat the viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing tape.

[0039] Bond the tape to a polished silicon wafer and allow it to stand for 24 hours. Test the 180° peel strength before light curing using a peel strength tester at a peel speed of 300 mm / min. Test each set of specimens three times, and take the average value.

[0040] The adhesive tape was bonded to a polished silicon wafer and cured in a UV curing machine (2 kW) for 45 seconds. The tape was then left to stand for 24 hours. The 180° peel strength after curing was measured using a peel strength tester at a peel speed of 300 mm / min. Each set of specimens was tested three times, and the average value was calculated.

[0041] Bond the tape to a polished silicon wafer and allow it to sit for 24 hours. Then, soak it in a 5% hydrochloric acid solution for 12 hours. Remove the sample, dry it, and test its 180° peel strength using a peel strength tester at a speed of 300 mm / min. Each set of samples was tested three times, and the average value was calculated.

[0042] Table 1 Properties of viscosity-reducing adhesive

[0043] After testing, Examples 1 to 4 used polytetramethylene ether diol and terminal hydroxyl allyloxy polyester as polyols, reacted with isocyanate monomers and chain extenders to obtain polyurethanes containing alkenyl groups, which were then compounded with reactive diluents and photoinitiators. The resulting viscosity-reducing adhesive had a 180° peel strength of only 2.61-3.23 N / 25mm after photocuring, showing excellent viscosity-reducing properties and easy-to-peel effects. This is mainly because the side chains of the terminal hydroxyl allyloxy polyester and the polyurethane prepared therefrom contain alkenyl groups with less steric hindrance, which can undergo better photocuring cross-linking reactions with reactive diluents. After photocuring, the cured adhesive film of the viscosity-reducing adhesive shrinks in volume, and wrinkles and concave-convex shapes appear on the surface of the adhesive layer, reducing the flatness of the adhesive layer and the contact area between the adhesive layer and the silicon wafer, thereby reducing the bonding performance and peel strength, showing excellent viscosity-reducing properties and easy-to-peel effects. And after being soaked in hydrochloric acid solution, it still shows high peel strength and excellent acid resistance. This is mainly because the added 2,2-dibutylpropane-1,3-diol contains a butyl structure with large steric hindrance and hydrophobicity, which can reduce the contact between water molecules and hydrochloric acid and polyester molecular chains, thereby inhibiting the acidolysis of polyester molecular chains and improving the acid resistance of polyurethane adhesive.

[0044] In Comparative Example 1, isophthaloyl chloride is used instead of 5-allyloxyisophthaloyl chloride. The prepared terminal hydroxyl polyester and polyurethane adhesive do not contain alkenyl groups. The polyurethane cannot undergo photocuring reaction. The photocrosslinking reaction occurs only by the active diluent dipropylene glycol diacrylate itself. The viscosity reduction effect is very poor, and the 180° peel strength after photocuring is very large.

[0045] In Comparative Example 2, butylene dichloride is used instead of 5-allyloxyisophthaloyl chloride. The main chains of the prepared hydroxy-terminated polyester and polyurethane contain alkenyl groups, which have large steric hindrance and low activity in the photocuring reaction with the reactive diluent, resulting in poor viscosity reduction effect. The 180° peel strength after photocuring is significantly greater than that of Example 1.

[0046] In Comparative Example 3, 1.3-propylene glycol is used instead of 2,2-dibutylpropane-1,3-diol. The prepared terminal hydroxy allyloxy polyester and polyurethane do not contain butyl structures with large steric hindrance and hydrophobicity, which makes it difficult to effectively inhibit the acid hydrolysis of the polyester molecular chain, resulting in easy acid hydrolysis of the polyurethane glue, low peel strength after acid immersion, and poor acid resistance.

[0047] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing an acid-resistant adhesive tape, characterized in that: The preparation method comprises the following steps: S1. Add N,N-dimethylformamide, 2,2-dibutylpropane-1,3-diol, triethylamine, and 5-allyloxyisophthaloyl chloride to a reaction vessel, stir to react, and then filter. Add the filtrate to water, stir, and then filter. Wash the product and dry it to obtain a hydroxy-terminated allyloxy polyester. S2. Add polytetramethylene ether glycol, terminal hydroxy allyloxy polyester, isocyanate monomer, and dibutyltin dilaurate into a reaction container, and carry out polymerization reaction in a nitrogen atmosphere; add 1,4-butanediol and acetone, carry out chain extension reaction, add active diluent, dry and remove acetone, add photoinitiator, stir and mix to obtain acid-resistant viscosity-reducing adhesive; finally, coat the acid-resistant viscosity-reducing adhesive on the surface of the PET release film to obtain an acid-resistant viscosity-reducing adhesive tape.

2. The method for preparing the acid-resistant adhesive tape according to claim 1, wherein: The molar ratio of 2,2-dibutylpropane-1,3-diol, triethylamine, and 5-allyloxyisophthaloyl chloride in S1 is (1.2-1.3):(2-2.2):

1.

3. The method for preparing the acid-resistant adhesive tape according to claim 2, wherein: The preparation method of 5-allyloxyisophthaloyl chloride comprises the following steps: adding dichloromethane, N,N-dimethylformamide, 5-allyloxyisophthalic acid in a molar ratio of 1:(6-8), and thionyl chloride into a reaction vessel, heating to 40-50° C., condensing and refluxing for 4-6 hours, performing reduced pressure distillation, and drying to obtain 5-allyloxyisophthaloyl chloride.

4. The method for preparing the acid-resistant adhesive tape according to claim 1, wherein: The reaction in S1 is first carried out at 0-5°C for 40-60 min, and then at 20-30°C for 4-6 h.

5. The method for preparing the acid-resistant adhesive tape according to claim 1, wherein: The polymerization reaction in S2 is carried out at 70-80° C. for 3-4 hours.

6. The method for preparing the acid-resistant adhesive tape according to claim 1, wherein: The chain extension reaction in S2 is carried out at 40-50° C. for 60-90 minutes.

7. The method for preparing the acid-resistant adhesive tape according to claim 1, wherein: The mass ratio of polytetramethylene ether diol, terminal hydroxyl allyloxy polyester, isocyanate monomer, reactive diluent, and photoinitiator in S2 is (110-160): (22-40): (45-66): (9-11): (28-36): (6.2-8.5).

8. The method for preparing the antistatic UV viscosity-reducing adhesive according to claim 7, characterized in that: The isocyanate monomer is isophorone diisocyanate or toluene-2,4-diisocyanate.

9. The method for preparing the acid-resistant adhesive tape according to claim 7, wherein: The active diluent is tripropylene glycol diacrylate or dipropylene glycol diacrylate; the photoinitiator is TPO.

Images