Radiation-curable adhesive

Abstract

The invention discloses a radiation-curable adhesive, and aims to provide a novel benzophenone-terminated polyurethane resin which mainly overcomes the defects of poor thermal stability and difficult surface curing of the existing unsaturated group-terminated polyurethane resin, and the radiation-curable adhesive is a reaction product of components (I), (II) and (III): at least one polyisocyanate (I); at least one polyol compound (II) containing at least two polyol compounds capable of reacting with isocyanate groups; and (III) at least one compound containing a benzophenone capable of reacting with an isocyanate group; belongs to the technical field of novel polymer materials.

Description

[0001] This application is a divisional application. The application number of the parent application is 202110438610.X, the application date is April 22, 2021, and the name of the invention is "Radiation-curable benzophenone-terminated polyurethane resin and its application". Technical Field

[0002] The invention belongs to the technical field of new polymer materials, and in particular relates to a radiation-curable adhesive. Background Art

[0003] Radiation-curable polyurethane resins are increasingly widely used to replace traditional adhesive materials because they can save energy and protect the environment, improve production efficiency, reduce material consumption, reduce plant area, and prevent the emission of volatile organic compounds (VOCs). Unsaturated end-group polyurethane resins are currently the most commonly used radiation-curable materials. For example, U.S. Patent No. 5,578,693 discloses a radiation-curable polyfunctional unsaturated end-group polyurethane oligomer, which is the reaction product of a polyurethane oligomer containing an unsaturated end group of isocyanate and an alkoxylated polyol. These unsaturated group-terminated polyurethane resins can be quickly cured by exposure to radiation, such as ultraviolet light. However, unsaturated group-terminated polyurethane resins still have some obvious disadvantages, and their material design and technology need to be further improved and innovated.

[0004] The unsaturated end groups contained in polyurethane resin are generally acrylic, methacrylic, and vinyl. These unsaturated groups have poor thermal stability and will undergo self-polymerization or other side reactions at high temperatures or when stored for a long time, which is not conducive to product production, processing, transportation and storage. A small amount of antioxidant heat stabilizer is usually added to improve the stability of the product. However, the addition of these antioxidant heat stabilizers will also reduce the efficiency of radiation curing, especially the free radical UV light curing speed.

[0005] Another disadvantage of unsaturated group-terminated polyurethane resins is that surface UV curing is greatly affected by air oxygen, and it is difficult to achieve complete curing of the coating surface under normal conditions. Amine additives, such as dimethyl para-toluidine and diethyl o-toluidine, are used commercially to improve the surface UV curing of acrylate-terminated polyurethane resins. However, these amine additives pose health risks during processing. Obviously, the method of adding amine additives to unsaturated group-terminated polyurethane resins is not suitable for many applications that may come into contact with food or the human body.

[0006] Commercially, small molecule photoinitiators are often added to photocurable formulations to improve the surface UV curing of acrylate-terminated polyurethane resins. However, this technical approach also has some obvious negative consequences: (1) Excessive initiators in the formulation will cause excessive curing inside the coating, affecting the performance of the product; (2) Due to the strong UV absorption ability of the initiator, excessive initiators cause the UV light intensity to decay sharply in the coating, significantly reducing the curable thickness of the coating; (3) After curing, a large amount of photoinitiator decomposition byproducts exists in the coating, resulting in strong odor and high VOC. Summary of the invention

[0007] To this end, the first object of the present invention is to provide a benzophenone-terminated polyurethane resin to improve the shortcomings of the existing unsaturated group-terminated polyurethane resins, such as poor thermal stability and difficult surface curing.

[0008] The second object of the present invention is to provide the use of the benzophenone-terminated polyurethane resin.

[0009] To achieve the above object, the radiation-curable benzophenone-terminated polyurethane resin provided by the present invention is made of the following components in parts by weight:

[0010] At least one polyisocyanate (I), the weight percentage of which is 5-95wt%;

[0011] At least one polyol compound (II) containing at least two isocyanate groups, the weight percentage of which is 5-95wt%;

[0012] At least one benzophenone compound (III) having a benzophenone group capable of reacting with an isocyanate group has a weight percentage of 0.1-5 wt%.

[0013] The radiation-curable benzophenone-terminated polyurethane resin has a structural formula of one of Formula 1 to Formula 7:

[0014] (1)PU-NH-CO-(O-CH2-CH2-CH2-CH2-CH2CO) n -O-BP;

[0015] (2)PU-NH-CO-(O-CH2-CH2) n -O-BP;

[0016] (3)PU-NH-CO-(O-CH2-CH2-CH2-CH2) n -O-BP;

[0017] (4)PU-NH-CO-(O-CH2-CH2-CH3) n -O-BP;

[0018] (5)PU-NH-CO-(O-CHOH-CH2) n -O-BP;

[0019] (6)PU-NH-CO-(O-CH2-CHOH) n -O-BP;

[0020] (7) PU-NH-CO-NH-BP;

[0021] Wherein: in Formula 1 to Formula 7, n is an integer between 0 and 50; BP is benzophenone; and PU is the main chain of the polyurethane resin.

[0022] The polyisocyanate (I) of the present invention is selected from aliphatic polyisocyanates, alicyclic polyisocyanates, blocked polyisocyanates, aromatic polyisocyanates, or one or more mixtures thereof. Preferred are toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), triphenylmethane triisocyanate, toluene diisocyanate trimer, hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, etc.

[0023] The polyol compound (II) of the present invention is selected from monomeric ethylene oxide, (low) polymer polyols, polyester polyols, polyether polyols, polybutadiene-derived polyols, hydrogenated polybutadiene-derived polyols, or one or more mixtures thereof. Preferred are ethylene glycol (EG), diethylene glycol (DEG), 1,2-propylene glycol (1,2-PG), 1,4-butanediol (BDO), neopentyl glycol (NPG), 2-methylpropanediol (MPD), the most commonly used diols in the synthesis of polyester polyols, 1,6-hexanediol (HDO), etc. (Low) polymer polyols include polyester polyols, polyether polyols, polybutadiene-derived polyols, hydrogenated polybutadiene-derived polyols, etc. Common polyether polyols include polyethylene oxide diols, polypropylene oxide diols, polyethylene oxide triols, polypropylene oxide triols, polytetrahydrofuran diols, ethylene oxide-propylene oxide copolymer diols, tetrahydrofuran-propylene oxide copolymer diols, etc. Common polyester polyols include polycaprolactone polyols, polycarbonate diols, carbon dioxide copolymer polyols, and polyol and polyacid copolymer polyols.

[0024] The average degree of polymerization of the above-mentioned (low) polymer polyol is greater than 5, more preferably greater than 10, and the average number average molecular weight of the polyol is greater than 400 g / mol, more preferably greater than 1000 g / mol.

[0025] The benzophenone compound (III) of the present invention is selected from hydroxy-containing benzophenone or benzophenone derivatives, amino-containing benzophenone or benzophenone derivatives, carboxyl-containing benzophenone or benzophenone derivatives, epoxy-containing benzophenone or benzophenone derivatives, isocyanate-containing benzophenone or benzophenone derivatives, or one or more mixtures thereof. Common benzophenone compounds include 4-(2-hydroxyepoxy)benzophenone, 4-hydroxybenzophenone, 4-carboxylbenzophenone, 4-aminobenzophenone, and their reaction products with epoxy compounds or diisocyanates.

[0026] The benzophenone-terminated polyurethane resin of the present invention is suitable for formulating radiation-curable coatings, comprising:

[0027] (1) 5-100 wt% benzophenone-terminated polyurethane resin;

[0028] (2) 0-50 wt% of one or more (meth)acrylic acid terminated polyurethane resins;

[0029] (3) 0-5 wt% of one or more photoinitiators;

[0030] (4) 0-40 wt% of one or more monomers;

[0031] The total amount of each component in the above composition is 100 wt%.

[0032] In the above coating composition, (meth) acrylic acid terminated polyurethane resin can be selectively added to further improve product performance. The (meth) acrylic acid terminated polyurethane resin includes but is not limited to the products of Sartomer Company of the United States, CN9021, CN981, CN820, CN962, CN964, CN965, CN934, and CN972; the products of AkzoNobelResins, ACTILANE130, ACTILANE170, ACTILANE35, and ACTILANE270, and ACTILANE290; GENOMER4269 supplied by Rahn Company of the United States; Ebecryl230, Ebecryl270, Ebecryl8803, Ebecryl4827, and Ebecryl6700 supplied by UCB Company of the United States.

[0033] In the above composition, a photoinitiator may be selectively added to further improve the photocuring performance of the product. The photoinitiator includes but is not limited to 1-hydroxycyclohexyl phenyl ketone (IRGACURE184), 2,2-dimethoxy-1,2-diphenylethyl-1-one (IRGACURE65D), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (IRGACURE819), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one (IRGACURE2959), 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)butanone (IRGACURE369), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropan-1-one (IRGACURE907), and 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCURH73), and combinations thereof.

[0034] In the above composition, monomers can be selectively added to further improve the optical coating performance of the product. Monomers include but are not limited to hydroxyethyl methacrylate, β-hydroxypropyl methacrylate, polyvinyl pyrrolidone, isobornyl methacrylate, glycidyl methacrylate, lauryl methacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, etc. In the above composition, other additives such as fillers, leveling agents, defoamers, and anti-aging agents can be selectively added to improve the leveling, optical properties, and weather resistance of the coating.

[0035] The benzophenone-terminated polyurethane resin of the present invention is suitable for formulating a radiation-curable adhesive. The radiation-curable adhesive composition comprises:

[0036] (1) 5-100 wt% of one or more benzophenone-terminated polyurethane resins;

[0037] (2) 0-60 wt % of one or more tackifiers;

[0038] (3) 0-50 wt% of one or more (meth)acrylic acid terminated polyurethane resins;

[0039] (4) 0-5 wt% of one or more photoinitiators;

[0040] (5) 0-80 wt% of one or more monomers;

[0041] Furthermore, the total amount of each component in the above composition is 100 wt%.

[0042] In the above adhesive composition, a tackifier may be selectively added to further improve the bonding performance of the product. The tackifier includes but is not limited to rosin-based tackifiers, such as Fora 185 (Eastman Chemical), Pine Crystal KE 311 (Arakawa), and Staybelite Ester 10 (Hercules); aliphatic and aromatic hydrocarbon resins, such as methyl styrene resin, Kristalex 3085, Kristalex 3070.

[0043] The radiation curable adhesive is suitable for making a wide range of pressure sensitive adhesive products. The coating methods used to prepare tapes, labels, or other pressure sensitive adhesive products include but are not limited to extrusion coating, narrow-mouth coating, gravure coating, curtain coating, slot coating, spin coating, screen coating. The coated substrate can be a film, tape, sheet, plate, foam, and the like; and can be made of various materials such as paper, fabric, plastic (polyester, PE, PP, BOPP and PVC), non-woven fabrics, metals, foils, glass, natural rubber, synthetic rubber, wood or plywood.

[0044] The radiation curable adhesive can be crosslinked in air or nitrogen by irradiation with ultraviolet light in the range of 200 to 500 nm. Suitable UV radiation sources include carbon arcs, mercury vapor arcs, fluorescent lamps with special ultraviolet emitting phosphors, electronic flash lamps, lasers of specific wavelengths, ultraviolet light emitting diodes or combinations thereof.

[0045] The benzophenone-terminated polyurethane resin of the present invention is suitable for preparing a radiation-curable encapsulation material. The radiation-curable encapsulation material composition comprises:

[0046] (1) 10-100 wt % of one or more benzophenone-terminated polyurethane resins;

[0047] (2) 5-95 wt% of one or more fillers;

[0048] (3) 0-50 wt% of one or more (meth)acrylic acid terminated polyurethane resins;

[0049] (4) 0-5 wt% of one or more photoinitiators;

[0050] (5) 0-80 wt% of one or more monomers;

[0051] Furthermore, the total amount of each component in the above composition is 100 wt%.

[0052] One or more fillers may be selectively added to the above adhesive composition to further improve the bonding performance of the product. The fillers include but are not limited to graphene, carbon black, zinc oxide, titanium dioxide, silicon dioxide, silicate inorganic fillers, carbonate inorganic fillers, sulfate inorganic fillers, or hollow glass microspheres.

[0053] Compared with the prior art, the technical solution provided by the present invention has the following technical advantages:

[0054] The present invention provides a benzophenone-terminated polyurethane resin, which improves the shortcomings of poor thermal stability and difficult surface curing of existing unsaturated group-terminated polyurethane resins. Compared with unsaturated group-terminated polyurethane resins, the terminated polyurethane resin has three important technical advantages: (1) the benzophenone group has better thermal stability and will not undergo high-temperature self-polymerization reactions similar to unsaturated groups; (2) the UV curing process of the benzophenone-terminated polyurethane is that the benzophenone activated by UV generates free radicals by hydrogen abstraction, and then the two free radicals couple to form crosslinks, so it is less affected by oxygen in the air and is more conducive to the curing of the coating surface; (3) the benzophenone-terminated polyurethane cures itself under UV radiation without the need to add small molecule photoinitiators, and the performance of the cured product is healthier and more environmentally friendly. DETAILED DESCRIPTION

[0055] The invention will now be illustrated by the following non-limiting examples.

[0056] Example 1 Synthesis of Benzophenone-Terminated Polyurethane Oligomers / Polymers

[0057] To a 3-liter round-bottom flask, add 62.5 g of diphenylmethane 4,4'-diisocyanate (MDI) and 0.4 g of dibutyltin dilaurate, 11.5 g of 4-(2-hydroxyepoxy)benzophenone, and a mixture of 0.01 g of p-methoxyphenol. After heating to 80°C with moderate stirring, slowly add a mixed solution of 600 g of toluene and 878 g of hydrogenated polybutadiene type difunctional polyol (L-2203, KratonPolymer). After the addition is complete, further heat to 100°C and maintain stirring at this temperature for 3 hours until the level of isocyanate (NCO) is less than 0.1%. The molecular weight and polydispersity of the benzophenone-terminated polyurethane polymer of this example are determined by ordinary gel permeation chromatography (GPC) method. Its number average molecular weight is 34,000 and the polydispersity is 2.95.

[0058] The sample of this embodiment was coated on a stainless steel plate with a dry adhesive coating of about 20 grams per square meter and baked in an oven at 110°C for 10 minutes to form a very viscous coating. However, the sample was irradiated with 100 mJ / cm2 of UV light in a desktop UV curing machine (medium pressure mercury column, H lamp, 120 W / cm2). 2After dosage, a non-sticky polyurethane elastomer coating is formed.

[0059] Example 2 Synthesis of acrylic acid terminated polyurethane oligomer / polymer

[0060] To a 3-liter round-bottom flask, add 62.5 g of diphenylmethane 4,4'-diisocyanate (MDI) and a mixture of 0.8 g of dibutyltin dilaurate, 5.8 g of 2-hydroxyethyl acrylate, and 0.1 g of p-methoxyphenol. After heating to 80°C with moderate stirring, slowly add a mixed solution of 600 g of toluene and 878 g of hydrogenated polybutadiene type difunctional polyol (L-2203, KratonPolymer). After the addition is completed, further heat to 90°C and maintain stirring at this temperature for 3 hours until the level of isocyanate (NCO) is less than 0.1%. Reduce the temperature to 80°C, then weigh 5 g of TPO (photoinitiator) into a 3-liter round-bottom flask, and continue stirring at this temperature for 1 hour. The molecular weight and polydispersity of the acrylic acid-terminated polyurethane polymer of this example are determined by ordinary gel permeation chromatography (GPC) method. Its number average molecular weight is 313,000 and its polydispersity is 2.76.

[0061] The sample of this embodiment was coated on a stainless steel plate with a dry adhesive coating of about 20 grams per square meter and baked in an oven at 110°C for 10 minutes to form a very viscous coating. The sample was irradiated with 100 mJ / cm2 in a desktop UV curing machine (medium pressure mercury column, H lamp, 120 W / cm2). 2 After the dosage, the polyurethane elastomer coating is still not completely cured and has a certain viscosity. When the finger gently presses the coating surface, obvious fingerprints will be formed.

[0062] Example 3 Preparation of solvent-based pressure-sensitive adhesive based on benzophenone-terminated polyurethane polymer

[0063] To a 3-liter round-bottom flask, add 62.5 g of diphenylmethane 4,4'-diisocyanate (MDI), 0.4 g of dibutyltin dilaurate, 11.5 g of 4-(2-hydroxyepoxy)benzophenone, and a mixture of 0.01 g of p-methoxyphenol. After heating to 80°C with moderate stirring, slowly add a mixed solution of 600 g of toluene and 878 g of hydrogenated polybutadiene type difunctional polyol (L-2203, KratonPolymer). After the addition is completed, further heat to 100°C and maintain stirring at this temperature for 3 hours until the level of isocyanate (NCO) is less than 0.1%. Reduce the temperature to 80°C and then weigh 5380 (solid tackifier resin), 2520 (liquid tackifying resin), 40 g HDODA (1,6-hexanediol diacrylate), and 1 g TPO (photoinitiator) were added to a 3 L round bottom flask and stirring was continued at this temperature for 1 hour.

[0064] The sample of this embodiment is coated on a 50 micron thick polyester film with a dry adhesive coating amount of about 50 grams per square meter. The coated sample is baked in an oven at 130°C for 6 minutes and then irradiated and cured in a desktop UV curing machine (medium pressure mercury column, H lamp, 120 watts / cm2). The UV curing dose is controlled at 60 millijoules / cm2. 2 The performance of the pressure-sensitive adhesive was evaluated by testing the 180° peel strength and room temperature adhesion retention on a stainless steel plate. The bonding time on the steel plate was controlled at 30 minutes and 24 hours, respectively. Table 1 lists the test conditions and results of the sample peel strength and room temperature adhesion retention.

[0065] Table 1. Results of 180° peel strength and room temperature adhesion retention

[0066] Example 3 Peel force (lamination for 30 minutes) Newton / 25mm 19.1 Peel force (lamination for 30 minutes) Newton / 25mm 20.5 Holding force (2 kg / 25 mm x 25 mm) >1000 minutes

[0067] Example 4 Preparation of hot melt pressure-sensitive adhesive based on benzophenone-terminated polyurethane polymer

[0068] After the 3L reactor was preheated to 60°C, 878g of hydrogenated polybutadiene polyol (L-2203, Kraton Polymer) was added. 2520, and 5380 are added to the reactor in sequence. The reactor is then heated to 110°C, and dry air is passed into the reactor to remove moisture from the reactants. After stirring at this temperature until the mixture in the reactor becomes a homogeneous system, 0.4g of dibutyltin dilaurate and 11.5g of 4-(2-hydroxyepoxy)benzophenone are added to the reactor, and stirring is continued for 15-30 minutes until the mixture in the reactor becomes a homogeneous system. At 110°C, a mixture of 62.5g of diphenylmethane 4,4'-diisocyanate (MDI), 0.1g of p-methoxyphenol, and 40g of HD0DA is slowly added to the reactor over 60 minutes to prevent the reaction temperature from exceeding 120°C. Stirring is continued at 110°C for 4 hours or more until the NCO% level is less than 0.1%. Finally, 0.6 g of TPO photoinitiator was added to the reactor and stirred for about 30 minutes to form a UV-curable hot-melt PSA with a viscosity of about 15,900 cps at 120°C.

[0069] The sample of this embodiment was coated on a 50 μm thick polyester film by hot melt adhesive coating method, with a coating thickness of about 50 g of adhesive per square meter, and then irradiated and cured in a desktop UV curing machine (medium pressure mercury column, H lamp, 120 W / cm2), with the UV curing dose controlled at 60 mJ / cm2.2 The performance of the pressure-sensitive adhesive was evaluated by testing the 180° peel strength and room temperature adhesion retention on a stainless steel plate. The bonding time on the steel plate was controlled at 30 minutes and 24 hours, respectively. Table 2 lists the test conditions and results of the 180° peel strength and room temperature adhesion retention of the samples.

[0070] Table 2. Results of 180° peel strength and room temperature adhesion retention

[0071] Example 4 Peel force (lamination for 30 minutes) Newton / 25mm 19.9 Peel force (lamination for 30 minutes) Newton / 25mm 21.5 Holding force (2 kg / 25 mm x 25 mm) >1000 minutes

[0072] Example 5 Preparation of hot melt pressure-sensitive adhesive based on benzophenone-terminated polyurethane copolymer

[0073] After the 2L reactor was preheated to 60°C, 75.5 g of thickener ( 2520), 61.0 g hydroxyl-terminated hydrogenated polybutadiene ( HLBHP3000) and 101.0g polyester polyol 3196), and the reactor was heated to 100°C. 152.0 g of viscosity enhancer ( 5380). The reactor was then heated to 110°C, and thereafter 0.05g BHT, 0.05g MEHQ, 0.89g 4-(2-hydroxyepoxy)benzophenone and 0.6g dibutyltin dilaurate (added in this order) were added to the reactor in sequence. Dry nitrogen was introduced into the reactor while the mixture in the reactor was stirred for 15-30 minutes. At 110°C, a mixture of 6.1g IPDI and 2.0g HDODA was slowly added to the reactor over 45 minutes. After the addition was completed, stirring was continued at 110°C for 3.0 hours. A mixture of 10.1g MDI and 4.0g HDODA was added again. After the addition was completed, stirring was continued at 110°C for 3 hours or more until the isocyanate content was less than 0.1%. Finally, 0.5g TPO photoinitiator was added to the reactor and stirred for about 30 minutes to form a UV-curable hot melt PSA with a viscosity of about 24,800cps at 120°C.

[0074] The sample of this embodiment was coated on a 50 μm thick polyester film by hot melt adhesive coating method, with a coating thickness of about 50 g of adhesive per square meter, and then irradiated and cured in a desktop UV curing machine (medium pressure mercury column, H lamp, 120 W / cm2), with the UV curing dose controlled at 80 mJ / cm2. 2 The performance of the pressure-sensitive adhesive was evaluated by testing the 180° peel strength and room temperature adhesion retention on a stainless steel plate. The bonding time on the steel plate was controlled at 30 minutes and 24 hours, respectively. Table 3 lists the test conditions and results of the 180° peel strength and room temperature adhesion retention of the samples.

[0075] Table 3. Results of 180° peel strength and room temperature adhesion retention

[0076] Example 5 Peel force (lamination for 30 minutes) Newton / 25mm 16.9 Peel force (lamination for 30 minutes) Newton / 25mm 17.5 Holding force (2 kg / 25 mm x 25 mm) >2000 minutes

[0077] Example 6 Benzophenone-terminated polyurethane based on polybutadiene polyol mixture

[0078] To a 2L reactor filled with nitrogen and equipped with a condenser, 72.5 g of hydroxyl-terminated polybutadiene ( LBH-P2000, hydroxyl number is 46), 145.0g hydroxyl-terminated polybutadiene ( LBH-P5000, containing 21.7 hydroxyl numbers), 32.5 g of hydroxyl-terminated polybutadiene-poly (bdR20LM, containing 101 hydroxyl numbers), and 500 g of ethyl acetate. The average OH group per polybutadiene of the polyol mixture is 2.1. The reactor is heated to reflux temperature and maintained at reflux for 2 hours to remove water from the polyol polybutadiene mixture. Subsequently, the reactor is cooled to 70°C and a mixed solution of 0.4 g of dibutyltin dilaurate and 4 g of toluene is added to the reactor. After stirring for 15 minutes, 20.6 g of isophorone diisocyanate is added to make the NCO / OH equivalent ratio 1.05. The reactants are heated to reflux temperature in the reactor and maintained at reflux for 3 hours, then 1.02 g of 4-(2-hydroxyepoxy)benzophenone is added and reflux is continued until the level of isocyanate (NCO) is less than 0.1%.

[0079] The sample of this embodiment was coated on a stainless steel plate with a dry adhesive coating of about 25 grams per square meter and baked in an oven at 80°C for 20 minutes to form a very viscous coating. However, the sample was irradiated with 100 mJ / cm2 of UV light in a desktop UV curing machine (medium pressure mercury column, H lamp, 120 W / cm2). 2 After dosage, a non-sticky polyurethane elastomer coating is formed.

[0080] Example 7 Benzophenone-terminated polyurethane based on polyester polyol mixture

[0081] To a 3L reactor filled with nitrogen and equipped with a condenser, 110.0 g of hydroxyl-terminated polyester polyol ( 1842-90, hydroxyl number 90, poly(diethylene glycol adipate), 990.0g polyester polyol ( 1640-35, hydroxyl number of 35, poly(1,4-butylene glycol neopentyl glycol adipate), and 1000.0 g ethyl acetate. The average OH group per polyester of the polyol mixture is 2.22. The reaction kettle is heated to reflux temperature and maintained at reflux for 2 hours to remove water from the polyol polybutadiene mixture. It is then cooled to 70°C and a mixed solution of 0.9 g dibutyltin bis(acetylacetone) and 9 g toluene is added to the reaction kettle. After stirring for 15 minutes, 93 g isophorone diisocyanate is added to give an NCO / OH equivalent ratio of 1.05. The reactants are heated to reflux temperature in the reaction kettle and maintained at reflux for 3 hours, then 4.9 g 4-(2-hydroxyepoxy)benzophenone is added and reflux is continued until the isocyanate (NCO) level is less than 0.1%.

[0082] The sample of this embodiment was coated on a stainless steel plate with a dry adhesive coating of about 30 grams per square meter and baked in an oven at 80°C for 20 minutes to form a very viscous coating. However, the sample was irradiated with 100 mJ / cm2 of UV light in a desktop UV curing machine (medium pressure mercury column, H lamp, 120 W / cm2). 2 After dosage, a non-sticky polyurethane elastomer coating is formed.

[0083] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A radiation-curable adhesive, characterized in that The composition comprises the following components in weight percentage: 10-100% of benzophenone-terminated polyurethane resin and 5-95% of tackifier, 0-50% of (meth)acrylic acid-terminated polyurethane resin, 0-5% of photoinitiator, and 0-80% of monomer, wherein the total amount of each component in the composition is 100%; The benzophenone-terminated polyurethane resin is prepared from the following components: 5-95 wt% of at least one polyisocyanate (I); 5-95 wt% of at least one polyol compound (II) containing at least two isocyanate groups capable of reacting; and 0.1-5 wt% of at least one benzophenone compound (III) containing a benzophenone group capable of reacting with an isocyanate group; The structural formula of the benzophenone-terminated polyurethane resin is one of Formula 1 to Formula 7: (1)PU-NH-CO-(O-CH2-CH2-CH2-CH2-CH2CO) n -O-BP; (2)PU-NH-CO-(O-CH2-CH2) n -O-BP; (3)PU-NH-CO-(O-CH2-CH2-CH2-CH2) n -O-BP; (4)PU-NH-CO-(O-CH2-CH2-CH3) n -O-BP; (5)PU-NH-CO-(O-CHOH-CH2) n -O-BP; (6)PU-NH-CO-(O-CH2-CHOH) n -O-BP; (7) PU-NH-CO-NH-BP; Wherein: in Formula 1 to Formula 7, n is an integer between 1 and 50; BP is benzophenone; and PU is the main chain of the polyurethane resin.

2. The radiation-curable adhesive according to claim 1, characterized in that The polyisocyanate (I) is one of aliphatic polyisocyanate, alicyclic polyisocyanate, blocked polyisocyanate, aromatic polyisocyanate or any combination thereof.

3. The radiation-curable adhesive according to claim 2, characterized in that The polyol compound (II) is one of monomeric polyols and polymeric polyols or any combination thereof.

4. The radiation-curable adhesive according to claim 3, characterized in that The polyol compound is polyester polyol, polyether polyol, polyol derived from polybutadiene, polyol derived from hydrogenated polybutadiene, polycarbonate polyol, or carbon dioxide copolymer polyol, or a mixture thereof.

5. The radiation-curable adhesive according to any one of claims 1 to 4, characterized in that The benzophenone compound (III) is a benzophenone or a benzophenone derivative containing a hydroxyl group, a benzophenone or a benzophenone derivative containing an amino group, a benzophenone or a benzophenone derivative containing a carboxyl group, a benzophenone or a benzophenone derivative containing an epoxy group, a benzophenone or a benzophenone derivative containing an isocyanate group, or a mixture of one or more thereof.