Polyurethane coating adhesive for protective film for OLED process and preparation method thereof

Abstract

The invention discloses a polyurethane coating adhesive used for a protective film for an OLED process and a preparation method thereof, and belongs to the field of polyurethane coating adhesive for optical display devices. The polyurethane coating adhesive is composed of 100 parts of a main agent, 3 to 20 parts of a curing agent, 30 to 100 parts of a diluent, and 0.1 to 5 parts of an auxiliary agent by weight; the main agent is formed by the reaction of polyester polyol, polyether polyol, hydroxy acrylic resin, isocyanate monomer, solvent, catalyst, viscosity reducer, and light stabilizer; the curing agent is a prepolymer synthesized by the reaction of isocyanate monomer, isocyanate dimer, isocyanate trimer, polyether polyol, small molecule polyol, and catalyst. The shortcomings of the polyurethane protective film used in the traditional process, such as poor cutting effect, much residual adhesive after aging of double 85, and high peeling strength, are improved. When undergoing laser cutting, transfer process, and other processes, no powder falling, residue, and the like will occur, so as to avoid contamination of the OLED screen.

Description

Technical Field

[0001] The present invention relates to the field of polyurethane coating adhesive for optical display devices, and in particular to a polyurethane coating adhesive for a protective film required in an OLED flexible panel manufacturing process and a preparation method thereof. Background Art

[0002] With the development of the electronics industry, especially the rapid development of the mobile Internet industry, the demand for mobile terminal devices such as mobile phones and tablets has increased sharply, and OLED screens, especially flexible OLED screens, can provide necessary equipment support for curved screens, folding screens, and high-definition display devices. In recent years, the growth rate has been more than 30% per year. The technological innovation of touch display panels is rapid, and the requirements for the protective film required in the manufacturing process of touch display products are also getting higher and higher.

[0003] The manufacturing process of OLED screen involves the protection and cutting of the entire OLED screen, as well as the low peel strength of the subsequent OLED process protective film (the adhesion after the double 85 test is required to be kept below 2gf / 25mm). For the extremely precise OLED manufacturing process, the protective film involved is required to have good air exhaust properties. When the protective film is attached to the OLED screen for a long time, due to the influence of adverse conditions such as temperature and humidity, it is ensured that there will be no residual glue (the migration of small molecules in the colloid of the protective film causes residues on the glass screen), bubble circle marks and other undesirable phenomena; at the same time, during the laser cutting and transfer processes, no powder loss, residue and the like will occur, so as to avoid contamination of the OLED screen.

[0004] The coating pressure-sensitive adhesive used for the protective film generally has three systems: silicone resin, acrylic resin, and polyurethane resin. When silicone resin is used in the pressure-sensitive adhesive layer, it has good wettability and bonding strength, but its pressure-sensitive adhesive component is easy to contaminate the adherend; when acrylic resin is used in the pressure-sensitive adhesive layer, it will not contaminate the adherend during peeling, but due to its high brittleness, it is easy to produce adhesive residue during peeling; polyurethane resin can avoid the shortcomings of the above two systems and achieve the unity of wettability and low residue. However, as a protective film coating adhesive for OLED process, it is also necessary to ensure that the initial adhesion and the adhesion after the double 85 test are always kept below 2gf / 25mm; no residue or floccules should appear during cutting; in addition, it is also necessary to ensure that the coating appearance is flat and does not turn yellow. After 5 days of high temperature and high humidity aging, the double 85 test will not form residual adhesive, whitening, powdering, etc. on the glass surface. It is difficult for general polyurethane coating adhesives to achieve all the above-mentioned properties.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a polyurethane coating adhesive and a preparation method for a protective film for an OLED process, which has high light transmittance, low film tearing voltage, stable viscosity over time, a peeling force of less than 2gf / 25mm, and after double 85, 5-day high temperature and high humidity aging, will not form residual adhesive, whitening, powdering, etc. on the glass surface, thereby solving the above-mentioned technical problems existing in the prior art.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A polyurethane coating adhesive for a protective film for an OLED process, the polyurethane coating adhesive is composed of a main agent, a curing agent, a diluent and an auxiliary agent, and the amount of each raw material in parts by weight is:

[0009] 100 parts of main agent,

[0010] 3 to 20 parts of curing agent,

[0011] 30 to 100 parts of diluent,

[0012] 0.1 to 5 parts of additives;

[0013] The main agent is a polyurethane formed by the reaction of polyester polyol, polyether polyol, hydroxy acrylic resin, isocyanate monomer, solvent, catalyst, viscosity reducer and light stabilizer;

[0014] The curing agent is a prepolymer synthesized by reacting one or more of isocyanate monomers, isocyanate dimers, and isocyanate trimers with polyether polyols, small molecule polyols, and catalysts.

[0015] Preferably, in the above polyurethane coating adhesive, the main agent is made of the following raw material components in parts by weight: 10 to 30 parts of polyester polyol, 20 to 60 parts of polyether polyol, 5 to 20 parts of hydroxy acrylic resin, 2 to 20 parts of isocyanate monomer, 20 to 40 parts of solvent, 0.000003 to 0.0005 parts of catalyst, 1 to 30 parts of viscosity reducer and 0.0001 to 0.001 parts of light stabilizer.

[0016] Preferably, in the main agent of the above-mentioned polyurethane coating adhesive, the number average molecular weight of the polyester polyol is 500 to 3000;

[0017] The number average molecular weight of the polyether polyol is 200 to 20,000, the functionality is 2 to 4, and the weight proportion of ethylene oxide in the polyether polyol is 10 to 90%;

[0018] The number average molecular weight of the hydroxy acrylic resin is 1000 to 10000;

[0019] The isocyanate monomer is one or a mixture of two of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, naphthalene diisocyanate and hexamethylene diisocyanate;

[0020] The solvent is one or a mixture of two or three of toluene, xylene, ethyl acetate, acetone and butanone;

[0021] The catalyst is one or two of an organic bismuth catalyst, an organic tin catalyst or a temperature-sensitive catalyst;

[0022] The viscosity reducing agent is one or two of isooctyl hexadecanoate, epoxy-modified soybean oil, and dodecylphenyl sulfonate;

[0023] The light stabilizer is a complex of a hindered phenol light stabilizer and an ultraviolet absorber.

[0024] Preferably, the synthetic raw materials of the polyester polyol in the main agent include crystalline polyol and aliphatic polyacid.

[0025] Preferably, the crystalline polyol is one or more of neopentyl glycol, 2-methyl-2,4-pentanediol, and hexanediol;

[0026] The aliphatic polyacid is one or more of adipic acid, azelaic acid and sebacic acid.

[0027] Preferably, in the above-mentioned polyurethane coating adhesive, the curing agent is a prepolymer synthesized by reacting one or more of isocyanate monomers, isocyanate dimers, isocyanate trimers with polyether polyols, small molecule polyols and catalysts. Preferably, it is a prepolymer formed by reacting a trimer of toluene diisocyanate and a trimer of hexamethylene diisocyanate with a polyether polyol having a molecular weight of 400 to 4000, a small molecule polyol and a catalyst DMDEE at a temperature of 60 to 90°C for 1 to 4 hours.

[0028] Preferably, in the curing agent, the small molecule polyol is at least one of diethylene glycol, dipropylene glycol and glycerol.

[0029] Preferably, the diluent is one or more of ethyl acetate, methyl acetate, toluene, xylene, acetone, and butanone;

[0030] The auxiliary agent is one or more of an antistatic agent and a defoaming and leveling agent.

[0031] A method for preparing a polyurethane coating adhesive used for a protective film for an OLED process according to the present invention comprises:

[0032] Preparation of main agent:

[0033] According to the formula of the main agent, polyester polyol, polyether polyol, hydroxy acrylic resin, isocyanate monomer, solvent, catalyst, viscosity reducer and light stabilizer are taken as raw material components;

[0034] In the first step, polyester polyol and polyether polyol are added to a reaction kettle, heated to 120°C, vacuumed and dehydrated for 1 hour, cooled to 60-70°C, isocyanate monomer is added, kept at 60-70°C for 1 hour, heated to 80-110°C, kept for 2 hours;

[0035] The second step is to add 10 to 20 parts of solvent, catalyst and hydroxy acrylic resin, keep the temperature at 80 to 90°C, and continue the reaction for 2 hours;

[0036] The third step is to add the remaining solvent, viscosity reducer and light stabilizer, cool to 50-70°C, and then discharge the material to obtain the main agent;

[0037] Preparation of curing agent:

[0038] According to the formula of the curing agent, one or more of isocyanate monomers, isocyanate dimers, and isocyanate trimers are taken together with the raw material components of polyether polyol, small molecule polyol, and catalyst;

[0039] One or more of isocyanate monomers, isocyanate dimers, and isocyanate trimers, polyether polyols, small molecule polyols, and catalysts are added to a reaction kettle at 60 to 90° C. and reacted for 1 to 4 hours to form a prepolymer, which is a curing agent;

[0040] The prepared main agent, curing agent, diluent and auxiliary agent are uniformly mixed to form a liquid glue, which is the polyurethane coating glue of the present invention.

[0041] Compared with the prior art, the polyurethane coating adhesive used for the protective film for OLED process provided by the present invention and the preparation method thereof have the following beneficial effects:

[0042] By introducing hydroxy acrylic resin into the polyurethane main agent, scientifically modifying the curing agent component and rationally matching polyether polyols with different molecular weights, functionalities and EO / PO ratios, the shortcomings of the polyurethane protective film used in the traditional process, such as poor cutting effect, much residual adhesive after aging in the double 85 test, and high peel strength, are improved. The polyurethane coating adhesive has high light transmittance, low film tearing voltage, stable viscosity over time, peeling force <2gf / 25mm, and after double 85, 5 days of high temperature and high humidity aging, it will not form residual adhesive on the glass surface, whitening, powdering, etc. DETAILED DESCRIPTION

[0043] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in combination with the specific content of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0044] First, the terms that may be used in this article are explained as follows:

[0045] The term “and / or” means that either or both of them can be realized at the same time. For example, X and / or Y means both “X” or “Y” and “X and Y”.

[0046] The terms "include", "comprises", "contains", "has" or other descriptions with similar semantics should be interpreted as non-exclusive inclusion. For example, including certain technical feature elements (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, procedures, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or products, etc.) should be interpreted as including not only certain technical feature elements explicitly listed, but also other technical feature elements known in the art that are not explicitly listed.

[0047] The term "consisting of..." means excluding any technical feature elements not explicitly listed. If this term is used in a claim, it will make the claim closed, so that it does not contain technical feature elements other than the technical feature elements explicitly listed, except for the conventional impurities related to them. If this term only appears in a clause of a claim, it only limits the elements explicitly listed in the clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0048] The term "parts by mass" refers to the mass part relationship between multiple components. For example, if component X is described as x parts by mass and component Y is y parts by mass, then the mass parts of component X and component Y are x:y. 1 part by mass can represent any mass, for example, 1 part by mass can be represented as 1 kg or 3.1415926 kg. The sum of the mass parts of all components is not necessarily 100 parts, but can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, proportions and percentages described herein are all by mass.

[0049] When concentration, temperature, pressure, size or other parameters are expressed in the form of a numerical range, the numerical range should be understood to specifically disclose all ranges formed by the pairing of any upper limit, lower limit, and preferred value in the numerical range, regardless of whether the range is explicitly stated; for example, if a numerical range of "2 to 8" is stated, the numerical range should be interpreted as including ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise specified, the numerical ranges stated herein include both their end values ​​and all integers and fractions within the numerical range.

[0050] The following is a detailed description of the polyurethane coating adhesive used for the protective film for the OLED process provided by the present invention and its preparation method. The contents not described in detail in the embodiments of the present invention belong to the prior art known to professional and technical personnel in the field. If no specific conditions are specified in the embodiments of the present invention, the conventional conditions in the field or the conditions recommended by the manufacturer are followed. The reagents or instruments used in the embodiments of the present invention without indicating the manufacturer are all conventional products that can be purchased commercially.

[0051] The embodiment of the present invention provides a polyurethane coating adhesive used for a protective film for an OLED process. The protective film prepared by using the polyurethane coating adhesive according to a conventional method has high light transmittance, low film tearing voltage, stable viscosity over time (peeling force <2gf / 25mm), and after double 85, 5 days of high temperature and high humidity aging, no residual adhesive, whitening, powdering, etc. will be formed on the glass surface. Due to the poor resistance to moisture and heat aging of the polyurethane system itself, especially when the temperature is greater than 60°C and the humidity is greater than 60%, it is easy for the polyurethane resin to hydrolyze and precipitate small molecules. In order to improve the performance, the polyurethane coating adhesive of the present invention has been innovated in the following three aspects to the conventional adhesive coating adhesive for polyurethane protective film, based on the introduction of polyester polyols with certain crystallinity and polyether polyols with different molecular weights and functionalities: first, hydroxyl acrylic resin is introduced into the main agent, and the heat and humidity aging resistance of the whole system is enhanced through the reaction of hydroxyl acrylic resin with isocyanate raw materials, so that the prepared polyurethane coating adhesive has excellent resistance to double 85 test aging performance; second, the curing agent is modified, and a polyether with a certain flexible chain segment and a glycerol extension chain with a certain cross-linking degree are introduced into the commercially available trimer curing agent, so that after the synthetic curing agent is mixed with the prepared main agent, the arrangement of the soft and hard chain segments is more scientific and reasonable, thereby taking into account the curing performance of the polyurethane after aging. The ester coating can achieve fast surface drying speed, low bonding strength, and is not prone to defects such as residual glue and bubble marks after aging in the double 85 test; thirdly, through the reasonable combination of different polyether polyols, it can achieve excellent properties such as reasonable hardness and softness, good compatibility with polyester, and high light transmittance of adhesives. For example, the introduction of a trifunctional, 3000 molecular weight, 20% EO content polyether can achieve a reasonable glass transition temperature of the coating and is not prone to residual glue; by introducing a 2-functionality, 2000 molecular weight PO polyether, a lower peel strength can be achieved after the coating is formed, and the coating can be prevented from falling off; by introducing a low molecular weight pure EO polyether, it can be used as a chain extender to increase the molecular weight and enhance the cohesion, thereby ensuring that the coating has a faster surface drying time and film-forming appearance.

[0052] The polyurethane coating adhesive used in the protective film for OLED process that meets the above requirements of the present invention is composed of a main agent, a curing agent, a diluent and an auxiliary agent, and the amount of each raw material used is as follows by weight:

[0053] Table 1 Raw material ratio of polyurethane coating adhesive

[0054] Serial number Coating glue raw materials Weight 1 Main agent 100 2 Curing agent 3～20 3 Thinner 30～100 4 Additives 0.1～5

[0055] The raw material components of the main agent include: polyester polyol, polyether polyol, hydroxy acrylic resin, isocyanate, solvent, catalyst, viscosity reducer and light stabilizer; the amount of each raw material is shown in Table 2:

[0056] Table 2 Polyurethane coating adhesive main agent raw materials and proportions

[0057] Serial number Main agent raw material type Weight 1 Polyester polyols 10～30 2 Polyether polyols 20～60 3 Hydroxylated acrylic resin 5～20 4 Isocyanate monomer 2～20 5 Solvents 20～40 6 Viscosity reducer 1～30 7 catalyst 0.00003～0.00005 8 Light Stabilizer 0.00001～0.0001

[0058] In the main agent, the number average molecular weight of the polyester polyol used is 500 to 3000. Preferably, the raw materials for synthesizing the polyester polyol contain crystalline polyols such as neopentyl glycol, 2-methyl-2,4-pentanediol, hexanediol, and aliphatic polyacids such as adipic acid, azelaic acid, and sebacic acid. Preferably, commercially available polyester polyols such as XCP-200N or XCP-1000PM of Asahikawa Chemical, HD-310P, HD320H of Shanghai Huide, etc. can be selected.

[0059] The number average molecular weight of the polyether polyol used in the main agent is 200-20000, preferably 800-4000, the functionality is 2-4, and the weight proportion of ethylene oxide in the polyether polyol is 10-90%, more preferably 10-30%;

[0060] The number average molecular weight of the hydroxy acrylic resin used in the main agent is 1000 to 10000;

[0061] The isocyanate monomer used in the main agent is one or a mixture of two of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, naphthalene diisocyanate and hexamethylene diisocyanate, preferably dicyclohexylmethane diisocyanate or hexamethylene diisocyanate.

[0062] The solvent used in the main agent is one, two or three of toluene, xylene, ethyl acetate, acetone and butanone. Preferably, a mixture of toluene and ethyl acetate is used.

[0063] The catalyst used in the main agent is one or two of organic bismuth, organic tin or temperature-sensitive catalysts.

[0064] The viscosity reducing agent used in the main agent is one or two of isooctyl hexadecanoate, epoxy-modified soybean oil and dodecylphenyl sulfonate.

[0065] The light stabilizer in the main agent is a complex of a hindered phenol light stabilizer and an ultraviolet absorber.

[0066] The raw material components of the curing agent include: one or more of isocyanate monomers, isocyanate dimers, isocyanate trimers, small molecule polyols, polyether polyols and catalysts.

[0067] Preferably, the curing agent is a prepolymer formed by reacting 70 to 95 parts by weight of isocyanates such as trimer of toluene diisocyanate and / or trimer of hexamethylene diisocyanate, 5 to 20 parts of polyether polyol with a molecular weight of 400 to 4000, 1 to 10 parts of small molecule polyol, and 0.00001 to 0.0001 parts of catalyst DMDEE (bis(2,2-morpholineethyl)ether) at 60 to 90° C. for 1 to 4 hours; preferably, the small molecule polyol is one of diethylene glycol, dipropylene glycol, and glycerol, and more preferably, the small molecule polyol uses glycerol.

[0068] The diluent is one or more of ethyl acetate, methyl acetate, toluene, xylene, acetone and butanone.

[0069] The auxiliary agent is one or more of an antistatic agent and a defoaming and leveling agent.

[0070] The embodiment of the present invention provides a method for preparing the polyurethane coating adhesive used for the protective film for the OLED process, comprising the following steps:

[0071] Preparation of the main agent: taking the main agent raw materials of polyester polyol, polyether polyol, hydroxy acrylic resin, isocyanate, solvent, catalyst, viscosity reducer and light stabilizer;

[0072] In the first step, polyester polyol and polyether polyol are first added into a reaction kettle, heated to 120°C and vacuumed to remove water for 1 hour, then cooled to 60-70°C, and the isocyanate monomer required in the formula is added, and the reaction is carried out at 60-70°C for 1 hour, and then heated to 80-110°C, more preferably heated to 95-105°C, and the reaction is carried out for 2 hours;

[0073] The second step is to add 10 to 20 parts of the solvent required by the formula, a catalyst, and a hydroxy acrylic resin, keep the temperature at 80 to 90° C., and continue the reaction for 2 hours;

[0074] The third step is to add the remaining solvents, viscosity reducers, light stabilizers and other components in the formula, cool the temperature to 50-70°C, and then discharge the material to obtain the main agent of the polyurethane coating adhesive;

[0075] Preparation of curing agent: taking the trimer of toluene diisocyanate and the trimer of hexamethylene diisocyanate as curing agent, polyether polyol with a molecular weight of 400 to 4000, small molecule polyol, and catalyst DMDEE (bis(2,2-morpholineethyl) ether);

[0076] Add the trimer of toluene diisocyanate and the trimer of hexamethylene diisocyanate, polyether polyol with a molecular weight of 400 to 4000, small molecule polyol, and catalyst DMDEE (bis(2,2-morpholineethyl) ether) into a reaction kettle, and react at 60 to 90° C. for 1 to 4 hours to form a prepolymer, which is a curing agent;

[0077] The prepared main agent, curing agent, diluent and auxiliary agent are mixed according to the proportions in Table 1 to prepare a glue solution, thereby obtaining the polyurethane coating glue of the present invention.

[0078] In order to more clearly demonstrate the technical solution and the technical effects provided by the present invention, the polyurethane coating adhesive used for the protective film for the OLED process provided by the embodiment of the present invention and the preparation method thereof are described in detail below with reference to specific embodiments.

[0079] (I) The test method for polyurethane coating adhesive includes the following 4 steps:

[0080] The first step is to prepare the working fluid according to the ratio required in Table 1;

[0081] In the second step, the prepared working liquid is evenly coated on the PET substrate film by using a coating laminating machine, and after being dried in a multi-stage drying tunnel at a temperature of 70-120°C, it is laminated with the PET release film and rolled up to obtain a protective film coated with the polyurethane coating adhesive used in the OLED process protective film;

[0082] The third step is to place the protective film in an oven at 45-60°C for aging for 24-96 hours, cool it to room temperature, and then pass it through a die-cutting device to obtain a protective film product that can be used by downstream customers;

[0083] The fourth step is to cut the prepared protective film into samples of different sizes according to the test requirements, apply them to different substrates, and test the appearance, haze, light transmittance, adhesion, double 85 tolerance and other properties.

[0084] The amounts of raw materials used in the following synthesis examples are all in parts by weight.

[0085] Main agent synthesis example 1

[0086] 10 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, with a molecular weight of 1000), 18 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and an ethylene oxide ratio of 20%), and 16 parts of polyether polyol 2 (with a molecular weight of 2000 and a functionality of 2) are added into a reactor, heated to 120°C and vacuumed to remove water for 1 hour, then cooled to 60-70°C, 4 parts of hexamethylene diisocyanate are added and kept at 70°C for reaction for 1 hour, then heated to 80°C for reaction for 2 hours, then 15 parts of toluene solution, 200 ppm of catalyst stannous octoate, and 12 parts of hydroxy acrylic resin (with a molecular weight of 2000) are added, kept at 80°C for reaction for 2 hours, finally 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate, and 300 ppm of a light stabilizer are added, and the polyurethane coating adhesive main agent 1 of the present invention is obtained after the material is discharged after the temperature is reduced to 50°C.

[0087] Main agent synthesis example 2

[0088] 10 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, with a molecular weight of 1000), 18 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and an ethylene oxide ratio of 20%), and 14 parts of polyether polyol 2 (with a molecular weight of 2000 and a functionality of 2) were added to a reactor, heated to 120°C, vacuumed and dehydrated for 1 hour, then cooled to 60-70°C, and 6 parts of dicyclohexylmethacrylate were added. After the isocyanate is kept at 70°C for reaction for 1 hour, the temperature is raised to 80°C for reaction for 2 hours, and then 15 parts of toluene solution, 200 ppm of catalyst stannous octoate and 12 parts of hydroxy acrylic resin (molecular weight 2000) are added, and the reaction is continued at 80°C for 2 hours. Finally, 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate and 300 ppm of light stabilizer are added, and the temperature is lowered to 50°C and the material is discharged to obtain the polyurethane coating adhesive main agent 2 of the present invention.

[0089] Main agent synthesis example 3

[0090] 10 parts of polyester polyol (obtained by condensation polymerization of adipic acid and neopentyl glycol, with a molecular weight of 2000), 18 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and an ethylene oxide ratio of 20%) and 18 parts of polyether polyol 2 (with a molecular weight of 2000 and a functionality of 2) are added into a reactor, heated to 120°C and vacuumed to remove water for 1 hour, then cooled to 60-70°C, 4 parts of hexamethylene diisocyanate are added and kept warm at 70°C for 1 hour, then heated to 80°C and kept warm for 2 hours, then 15 parts of toluene solution, 200 ppm of catalyst stannous octoate and 10 parts of hydroxy acrylic resin (with a molecular weight of 2000) are added, kept warm at 80°C for further reaction for 2 hours, finally 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate and 300 ppm of light stabilizer are added, and the polyurethane coating adhesive main agent 3 of the present invention is obtained after the material is discharged after cooling to 50°C.

[0091] Main agent synthesis example 4

[0092] 10 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, with a molecular weight of 1000), 16 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and ethylene oxide accounting for 20%), 16 parts of polyether polyol 2 (with a molecular weight of 2000, a functionality of 2), and 2 parts of polyether polyol 3 (polyethylene glycol with a molecular weight of 200) were added to a reaction kettle, heated to 120°C, vacuumed and dehydrated for 1 hour, and then cooled to 60-70°C. ℃, then add 4 parts of hexamethylene diisocyanate and keep the reaction at 70 ℃ for 1 hour, heat to 80 ℃ and keep the reaction for 2 hours, then add 15 parts of toluene solution, 200ppm of catalyst stannous octoate and 12 parts of hydroxy acrylic resin (molecular weight 2000), keep the reaction at 80 ℃ for 2 hours, finally add 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate and 300ppm of light stabilizer, etc., cool to 50 ℃ and then discharge the material to obtain the polyurethane coating adhesive main agent 4 of the present invention.

[0093] Main agent synthesis example 5

[0094] 15 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, with a molecular weight of 1000), 18 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and an ethylene oxide ratio of 20%), and 18 parts of polyether polyol 2 (with a molecular weight of 2000 and a functionality of 2) are added into a reactor, heated to 120°C and vacuumed to remove water for 1 hour, then cooled to 60-70°C, 4 parts of hexamethylene diisocyanate are added and kept at 70°C for reaction for 1 hour, then heated to 80°C for reaction for 2 hours, then 15 parts of toluene solution, 200 ppm of catalyst stannous octoate, and 5 parts of hydroxy acrylic resin (with a molecular weight of 2000) are added, kept at 80°C for reaction for 2 hours, finally 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate, and 300 ppm of a light stabilizer are added, and the polyurethane coating adhesive main agent 5 of the present invention is obtained after the temperature is reduced to 50°C.

[0095] Main agent synthesis example 6

[0096] 10 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, with a molecular weight of 1000), 15 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and an ethylene oxide ratio of 20%), and 15 parts of polyether polyol 2 (with a molecular weight of 2000 and a functionality of 2) are added into a reactor, heated to 120°C and vacuumed to remove water for 1 hour, then cooled to 60-70°C, 5 parts of hexamethylene diisocyanate are added and kept at 70°C for reaction for 1 hour, then heated to 80°C for reaction for 2 hours, then 15 parts of toluene solution, 200 ppm of catalyst stannous octoate, and 15 parts of hydroxy acrylic resin (with a molecular weight of 2000) are added, kept at 80°C for reaction for 2 hours, finally 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate, and 300 ppm of a light stabilizer are added, and the polyurethane coating adhesive main agent 6 of the present invention is obtained after the temperature is reduced to 50°C.

[0097] Main agent synthesis example 7

[0098] 15 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, with a molecular weight of 1000), 20 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and an ethylene oxide ratio of 20%), and 20 parts of polyether polyol 2 (with a molecular weight of 2000 and a functionality of 2) are added into a reactor, heated to 120°C and vacuumed to remove water for 1 hour, then cooled to 60-70°C, 5 parts of hexamethylene diisocyanate are added, and the mixture is kept warm at 70°C for 1 hour, then heated to 80°C and kept warm for 2 hours, then 15 parts of toluene solution and 200ppm of catalyst stannous octoate are added, without adding hydroxylated acrylic resin, and the mixture is kept warm at 80°C for 2 hours, finally 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate and 300ppm of light stabilizer are added, and the mixture is cooled to 50°C and discharged to obtain the polyurethane coating adhesive main agent 7 used in the comparative example.

[0099] Main agent synthesis example 8

[0100] 10 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, with a molecular weight of 1000) and 33 parts of polyether polyol 1 (with a molecular weight of 3000, a functionality of 3, and an ethylene oxide ratio of 20%) are added to a reactor, heated to 120°C and vacuumed to remove water for 1 hour, then cooled to 60-70°C, and then 5 parts of hexamethylene diisocyanate are added and kept at 70°C for 1 hour, then heated to 80°C for 2 hours, and then 15 parts of toluene solution, 200ppm of catalyst stannous octoate and 12 parts of hydroxy acrylic resin (with a molecular weight of 2000) are added, and the reaction is continued at 80°C for 2 hours, and finally 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate and 300ppm of light stabilizer are added, and the polyurethane coating adhesive main agent 8 used in the comparative example is obtained after the material is discharged after the temperature is reduced to 50°C.

[0101] Main agent synthesis example 9

[0102] 10 parts of polyester polyol (obtained by condensation polymerization of adipic acid and 2-methyl-2,4-pentanediol, molecular weight 1000), 18 parts of polyether polyol 4 (molecular weight 3000, functionality 3, ethylene oxide ratio <10%) and 14 parts of polyether polyol 2 (molecular weight 2000, functionality 2) were added to the reactor, heated to 120°C, vacuumed and dehydrated for 1 hour, cooled to 60-70°C, and 6 parts of dicyclohexylmethane were added. After the diisocyanate is reacted at 70°C for 1 hour, the temperature is raised to 80°C for 2 hours, and then 15 parts of toluene solution, 200 ppm of catalyst stannous octoate and 12 parts of hydroxy acrylic resin (molecular weight 2000) are added, and the reaction is continued at 80°C for 2 hours. Finally, 15 parts of ethyl acetate, 10 parts of isooctyl hexadecanoate and 300 ppm of light stabilizer are added, and the temperature is reduced to 50°C before discharging the material to obtain the polyurethane coating adhesive main agent 9 used in the comparative example.

[0103] The contents of the various components of the polyurethane coating adhesive main agent obtained in the above main agent synthesis examples 1-9 are summarized in Table 3.

[0104] Table 3: Formula of main agent in different main agent synthesis examples (all by weight)

[0105]

[0106]

[0107] The synthesis process of curing agent 1 is as follows (each component is by weight):

[0108] First, 90 parts of the trimer of hexamethylene diisocyanate, 7 parts of a polyether polyol with a molecular weight of 1000 and 3 parts of glycerol as a small molecule chain extender were reacted at 70°C for 3 hours to obtain a curing agent 1. It can be seen that the trimer of hexamethylene diisocyanate was sampled in this embodiment, but since the performance of the dimer and isocyanate monomer of isocyanate is similar to that of the trimer of hexamethylene diisocyanate, if the dimer of isocyanate or the isocyanate monomer is selected and modified by the above method, similar performance can be achieved to meet the requirements of the curing agent.

[0109] Curing agent 2: a commercially available trimer of hexamethylene diisocyanate, with the Covestro brand being N3300 and the Wanhua Chemical brand being HT-100.

[0110] Example 1

[0111] The components of this embodiment are calculated by weight. 100 parts of the main agent 1 in the main agent synthesis example 1, 5 parts of the curing agent 1, 40 parts of ethyl acetate, 200ppm of antistatic agent (imide salt) and 200ppm of leveling agent (BYK-3560) are stirred evenly and then placed for 20 minutes until the bubbles disappear to obtain the polyurethane coating adhesive working solution. The prepared working solution is operated according to the above test method to obtain a surface protection film.

[0112] Example 2

[0113] Except that the main agent 2 in the main agent synthesis example 2 is used to replace the main agent 1 in the embodiment 1, the other operations remain unchanged to obtain the surface protection film.

[0114] Example 3

[0115] Except that the main agent 3 in the main agent synthesis example 3 is used to replace the main agent 1 in the embodiment 1, the other operations remain unchanged to obtain the surface protection film.

[0116] Example 4

[0117] Except that the main agent 4 in the main agent synthesis example 4 is used to replace the main agent 1 in the embodiment 1, the other operations remain unchanged to obtain the surface protection film.

[0118] Example 5

[0119] Except that the main agent 5 in the main agent synthesis example 5 is used to replace the main agent 1 in the embodiment 1, the other operations remain unchanged to obtain the surface protection film.

[0120] Example 6

[0121] Except that the main agent 6 in the main agent synthesis example 6 is used to replace the main agent 1 in the embodiment 1, the other operations remain unchanged to obtain the surface protection film.

[0122] Example 7

[0123] 100 parts of the main agent 1 in the main agent synthesis example 1, 10 parts of the curing agent 1, 40 parts of ethyl acetate, 100 ppm of antistatic agent (imide salt), leveling agent (BYK-3560), etc., are stirred evenly and left for 20 minutes until the bubbles disappear to obtain the polyurethane coating adhesive working solution. The prepared working solution is operated according to the above test method to obtain a surface protective film.

[0124] Example 8

[0125] 100 parts of the main agent 1 in the main agent synthesis example 1, 5 parts of the curing agent 2 commonly used on the market, i.e., unmodified trimer of hexamethylene diisocyanate, 40 parts of ethyl acetate, 100 ppm of antistatic agent (imide salt), leveling agent (BYK-3560), etc., are stirred evenly and then placed for 20 minutes until the bubbles disappear to obtain a polyurethane coating adhesive working solution. The prepared working solution is operated according to the above test method to obtain a surface protective film.

[0126] Example 9

[0127] Except that the main agent 2 in the main agent synthesis example 2 is used to replace the main agent 1 in Example 8, the other operations remain unchanged to obtain a surface protection film.

[0128] Comparative Example 1

[0129] Except that main agent 7 in main agent synthesis example 7 is used to replace main agent 1 in embodiment 1, other operations remain unchanged to obtain a surface protection film.

[0130] Comparative Example 2

[0131] Except that the main agent 8 in the main agent synthesis example 8 is used to replace the main agent 1 in the embodiment 1, the other operations remain unchanged to obtain the surface protection film.

[0132] Comparative Example 3

[0133] Except that main agent 9 in main agent synthesis example 9 is used to replace main agent 1 in embodiment 1, other operations remain unchanged to obtain a surface protection film.

[0134] Comparative Example 4

[0135] Use a foreign polyurethane adhesive 1401 for surface coating on the market, match it with its curing agent U-100 and prepare the working fluid according to its operating instructions, then use the prepared working fluid to operate the above test method to obtain the surface protection film.

[0136] The contents of the components of the working solutions prepared in the above Examples 1-9 and Comparative Examples 1-4 are summarized in Table 4.

[0137] Table 4: Summary of the contents of each component in the working solution configured in the embodiment and the comparative example

[0138]

[0139]

[0140] The properties of the surface protection films prepared in the above examples and comparative examples were evaluated by the following methods, and the test results are listed in Table 5.

[0141] Table 5: Performance evaluation results of protective films prepared in Examples and Comparative Examples

[0142]

[0143] Coating appearance: Indicates the appearance of the glue after film formation. ○ indicates a good appearance, △ indicates a slightly better appearance with a small amount of crystal points, and × indicates a poor appearance with an uneven surface.

[0144] Drying speed: refers to the time required for the glue to dry in a 70-120℃ oven until the surface is no longer sticky. If the drying time is less than 3 minutes, the drying speed is fast, and if it is more than 5 minutes, the drying speed is slow.

[0145] Wettability: Cut the sample into 5cm×10cm size, and put the 5cm wide side in contact with the glass plate at a 45° tilt. Then release your hand. The time (seconds) required for the sample to completely adhere to the peeling plate is used as the basis for evaluating the wettability. If the time is less than 5 seconds, the wettability is very good, and if it is more than 10 seconds, the wettability is poor.

[0146] Peel strength: Under the environment of 23℃×50%RH humidity, cut the sample into 25mm wide sheets, stick them on the test steel plate, and roll them back and forth three times with a 2kg roller. After leaving it for 20 minutes, clamp one end of the steel plate on the fixture of the tensile machine, and clamp one end of the film with the fixture at the other end. Peel it 180° at a speed of 300mm / min. The force value obtained is the peel strength. If the peel strength is less than 2gf / 25mm, it means that the film has good reprocessability, where 1gf=0.01N.

[0147] Cutting effect: When the surface film is cut, the slag on the cutting edge. ○ means that there is basically no slag on the cutting edge, and there is no pollution to the substrate. △ means that there is slight slag on the cutting edge, and there is slight pollution to the substrate. × means that there is serious slag on the cutting edge, and there is obvious pollution to the substrate.

[0148] Transparency: Turbidity was calculated using a turbidity meter HM-150 according to JIS-K-7136 based on the following equation: (%) = (Td / Tt) × 100 (Td: diffuse transmittance, Tt: total transmittance). The higher the turbidity, the lower the transparency. ○ indicates that the turbidity is less than 4%, and the transparency is good. △ indicates that the turbidity is greater than 4% and less than 8%, and the transparency is slightly poor. × indicates that the turbidity is greater than 8%, and the transparency is poor.

[0149] Residual adhesive (placed in double 85 environment for 5 days): After sticking the protective film on the glass plate, place it in an environment with a temperature of 85℃ and a humidity of 80% for 5 days, then remove the film and check whether there is white fog or residual adhesive on the glass plate. ○ indicates no residual adhesive or white fog, △ indicates slight residual adhesive, and × indicates obvious residual adhesive and white fog.

[0150] From the above examples 1-7, it is found that the protective film prepared by the polyurethane coating adhesive used for the protective film for the OLED process of the present invention has good coating appearance, fast drying speed, good wettability, good transparency, no slag after cutting, and if hydroxy acrylic resin is added in the example, after reasonable compounding of polyether, the protective film also has excellent characteristics such as low peel strength and good residual adhesive after double 85. Examples 8 to 9 use the curing agent commonly used on the market, and it can be seen that the drying time and peel strength are slightly higher. In comparative example 1, if acrylic resin is not added, it will affect the cutting effect and double 85 performance. In comparative example 2, the content of trifunctional polyether is relatively high, which will also affect the cutting effect. In comparative example 3, if the content of ethylene oxide in the polyether polyol is low, it will affect the transparency of the film.

[0151] In summary, the present invention improves the shortcomings of the polyurethane protective film used in the traditional process, such as poor cutting effect, much residual adhesive after aging of double 85, and high peel strength, by introducing hydroxyl acrylic resin into the polyurethane main agent, scientifically modifying the curing agent component, and rationally matching polyether polyols with different molecular weights, functionalities, and EO / PO ratios.

[0152] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A polyurethane coating adhesive for a protective film for an OLED process, characterized in that: The polyurethane coating adhesive is composed of a main agent, a curing agent, a diluent and an auxiliary agent, and the amount of each raw material in parts by weight is as follows: 100 parts of main agent, 3 to 20 parts of curing agent, 30 to 100 parts of diluent, 0.1 to 5 parts of additives; The main agent is formed by reacting polyester polyol, polyether polyol, hydroxy acrylic resin, isocyanate monomer, solvent, catalyst, viscosity reducer and light stabilizer; the main agent is made of the following raw material components in parts by weight: 10-30 parts of polyester polyol, 20-60 parts of polyether polyol, 5-20 parts of hydroxy acrylic resin, 2-20 parts of isocyanate monomer, 20-40 parts of solvent, 0.0002 parts of catalyst, 1-30 parts of viscosity reducer and 0.0003 parts of light stabilizer; the polyether polyol includes: polyether polyol 1 and polyether polyol 2, the molecular weight of polyether polyol 1 is 3000, the functionality is 3, and the proportion of ethylene oxide is 20%; the molecular weight of polyether polyol 2 is 2000, and the functionality is 2; The curing agent is a prepolymer synthesized by reacting one or more of isocyanate monomers, isocyanate dimers, and isocyanate trimers with polyether polyols, small molecule polyols, and catalysts.

2. The polyurethane coating adhesive used for the protective film for OLED process according to claim 1, characterized in that: In the main agent, the number average molecular weight of the polyester polyol is 500 to 3000; The number average molecular weight of the hydroxy acrylic resin is 1000 to 10000; The isocyanate monomer is one or a mixture of two of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, naphthalene diisocyanate and hexamethylene diisocyanate; The solvent is one or a mixture of two or three of toluene, xylene, ethyl acetate, acetone and butanone; The catalyst is one or two of an organic bismuth catalyst, an organic tin catalyst or a temperature-sensitive catalyst; The viscosity reducing agent is one or two of isooctyl hexadecanoate, epoxy-modified soybean oil, and dodecylphenyl sulfonate; The light stabilizer is a complex of a hindered phenol light stabilizer and an ultraviolet absorber.

3. The polyurethane coating adhesive used for the protective film for OLED manufacturing process according to claim 1, characterized in that: The synthetic raw materials of the polyester polyol in the main agent include crystalline polyol and aliphatic polyacid.

4. The polyurethane coating adhesive used for the protective film for OLED process according to claim 3, characterized in that: The crystalline polyol is one or more of neopentyl glycol, 2-methyl-2,4-pentanediol, and hexanediol; The aliphatic polyacid is one or more of adipic acid, azelaic acid and sebacic acid.

5. The polyurethane coating adhesive used for the protective film for OLED process according to any one of claims 1 to 4, characterized in that: The curing agent is a prepolymer formed by reacting one or more of a trimer of toluene diisocyanate and a trimer of hexamethylene diisocyanate with a polyether polyol having a molecular weight of 400 to 4000, a small molecule polyol and a catalyst DMDEE at a temperature of 60 to 90° C. for 1 to 4 hours.

6. The polyurethane coating adhesive used for the protective film for OLED manufacturing process according to claim 5, characterized in that: In the curing agent, the small molecule polyol is at least one of diethylene glycol, dipropylene glycol and glycerol.

7. The polyurethane coating adhesive used for the protective film for OLED process according to any one of claims 1 to 4, characterized in that: The diluent is one or more of ethyl acetate, methyl acetate, toluene, xylene, acetone, and butanone; The auxiliary agent is one or more of an antistatic agent and a defoaming and leveling agent.

8. A method for preparing the polyurethane coating adhesive used for the protective film for OLED process according to any one of claims 1 to 7, characterized in that: include: Preparation of main agent: According to the formula of the main agent, polyester polyol, polyether polyol, hydroxy acrylic resin, isocyanate monomer, solvent, catalyst, viscosity reducer and light stabilizer are taken as raw material components; In the first step, polyester polyol and polyether polyol are added to a reaction kettle, heated to 120°C, vacuumed and dehydrated for 1 hour, cooled to 60-70°C, isocyanate monomer is added, kept at 60-70°C for 1 hour, heated to 80-110°C, kept for 2 hours; The second step is to add 10 to 20 parts of solvent, catalyst and hydroxy acrylic resin, keep the temperature at 80 to 90°C, and continue the reaction for 2 hours; The third step is to add the remaining solvent, viscosity reducer and light stabilizer, cool to 50-70°C, and then discharge the material to obtain the main agent; Preparation of curing agent: According to the formula of the curing agent, one or more of isocyanate monomers, isocyanate dimers, and isocyanate trimers are taken together with the raw material components of polyether polyol, small molecule polyol, and catalyst; One or more of isocyanate monomers, isocyanate dimers, and isocyanate trimers, polyether polyols, small molecule polyols, and catalysts are added to a reaction kettle at 60 to 90° C. and reacted for 1 to 4 hours to form a prepolymer, which is a curing agent; The prepared main agent, curing agent, diluent and auxiliary agent are evenly mixed to form a liquid glue, which is the polyurethane coating glue.

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