Polyurethane resin composition as well as preparation method and application thereof

Abstract

The invention provides a polyurethane resin composition as well as a preparation method and application thereof. The composition comprises phenolic epoxy acrylic resin, diisocyanate, polyhydroxy carboxylic acid, a first polymerization inhibitor, acid anhydride and a first anti-yellowing component, the first anti-yellowing component comprises a first anti-yellowing auxiliary agent, a second anti-yellowing auxiliary agent and an ultraviolet light stabilizer, and the mass ratio of the first anti-yellowing auxiliary agent to the second anti-yellowing auxiliary agent to the ultraviolet light stabilizer is 1.0: (0.1-5.0): (0-5.0); the mass ratio of the first polymerization inhibitor to the first anti-yellowing auxiliary agent in the first anti-yellowing component is 1.0: (0.2-10). The polyurethane resin has excellent anti-yellowing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a polyurethane resin composition, a preparation method and application thereof. BACKGROUND

[0002] Polyurethane is a kind of high polymer thermosetting material with excellent mechanical properties, which is usually prepared by stepwise polymerization of monoisocyanate (polyisocyanate) and polyol compound. Due to the presence of a large number of polar groups such as urethane, ester bond and ether bond in the molecular chain, it can produce intermolecular forces such as hydrogen bond with the surface of the substrate, thus having excellent bonding properties. In addition, polyurethane resin also has good oil resistance, excellent low-temperature impact resistance, bending resistance and fatigue resistance. With its good thermal insulation, chemical resistance, high and low temperature resistance, low water absorption and excellent electrical properties, polyurethane resin has become an extremely important polymer material, which is widely used in many technical fields such as aerospace, ship transportation, medical devices, electrical and electronic information.

[0003] The polyurethane resin produced in large scale in industry usually uses raw materials with high cost performance, such as diphenylmethane-4,4'-diisocyanate (MDI) or toluene-2,4-diisocyanate (TDI). However, the polyurethane resin prepared by using such raw materials has an inherent and difficult to overcome defect, i.e. poor yellowing resistance. Specifically, the reasons for this defect mainly include: (1) light aging yellowing: the aromatic structure such as benzene ring in the polyurethane molecular chain has strong absorption to ultraviolet light (especially 290-400 nm wave band), and the absorbed energy is enough to cause the breakage and rearrangement of the polyurethane molecular chain, thus degrading to produce chromophoric groups, resulting in irreversible yellowing of the material. (2) thermal oxidative aging yellowing: during synthesis, storage or use, the material is in a high temperature environment, or contacts with oxygen due to poor sealing, etc., and the ester group, ether bond and unsaturated double bond in the polyurethane molecular chain will undergo thermal oxidative degradation, which will also cause the material to yellow. This yellowing problem not only affects the appearance and gloss of the product, but also may cause problems such as cracking, blistering and adhesion loss, which is extremely unfavorable for the polyurethane material applied in electronic and electrical products, and will seriously affect the performance stability of the product and shorten its effective service life. At the same time, this defect also greatly limits the application of polyurethane resin in high-end fields (such as optical instruments, high-end transparent coatings, etc.) that require long-term high transparency and color stability. SUMMARY

[0004] The present application aims to at least partially solve one of the problems in the prior art. To this end, one object of the present application is to provide a polyurethane resin composition, a preparation method and application thereof.

[0005] In a first aspect, the present application provides a polyurethane resin composition. According to embodiments of the present application, the composition comprises: a phenolic epoxy acrylic resin, a diisocyanate, a polyhydroxy carboxylic acid, a first polymerization inhibitor, an acid anhydride, and a first anti-yellowing component; The first anti-yellowing component comprises a first anti-yellowing aid, a second anti-yellowing aid, and an ultraviolet light stabilizer, and the mass ratio of the first anti-yellowing aid, the second anti-yellowing aid, and the ultraviolet light stabilizer is 1.0:(0.1-5.0):(0-5.0), preferably 1.0:(1.0-3.0):(0.5-2.0), for example, the mass ratio is 1:0.1:0.01, 1:1:1, 1:2:2, 1:3:3, 1:5:5, 1:1:5, 1:2:5, 1:5:1, 1:5:3, etc. The mass ratio of the first polymerization inhibitor to the first anti-yellowing aid in the first anti-yellowing component is 1.0:(0.2-10), preferably 1.0:(2-20), for example, 1:0.2, 1:1, 1:2, 1:5, 1:10, etc.

[0006] In some embodiments of the present application, the first anti-yellowing component comprises a first anti-yellowing aid, a second anti-yellowing aid, and an ultraviolet light stabilizer. The first anti-yellowing aid and the second anti-yellowing aid function to capture free radicals and thus terminate chain reactions, or to reduce the activity of free radicals and allow them to slowly deactivate. The ultraviolet light stabilizer functions to block photo-initiation and reduce the generation of photo-induced free radicals. By using the first anti-yellowing aid, the second anti-yellowing aid, and the ultraviolet light stabilizer in combination, and by controlling the mass ratio of the first anti-yellowing aid, the second anti-yellowing aid, and the ultraviolet light stabilizer within the above range, the generated free radicals in the reaction process can be promptly and effectively captured and converted, thereby significantly reducing the degree of yellowing of the resin. In addition, the inventors have found that the first anti-yellowing aid inhibits the generation of free radicals or captures and converts free radicals, and the phenols in the first anti-yellowing aid and the phenols or quinones in the first polymerization inhibitor can form hydrogen bonds to form a 'net-like' structure. By controlling the mass ratio of the first anti-yellowing aid to the first polymerization inhibitor within the above range, free radicals can be better captured, and better anti-yellowing effects can be achieved.

[0007] In some embodiments of the present application, the first anti-yellowing aid includes at least one of butylmethoxyphenol, di-tert-butyl-p-cresol, tert-butyl hydroquinone, n-octyl gallate, antioxidant 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester), antioxidant 1024 (3-(3,5-di-tert-butyl-4-hydroxyphenyl)-N'-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]propionohydrazide), antioxidant 1035 (thiodiethylene bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), antioxidant 1076 (β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl ester), antioxidant 1077 (3,5-di-tert-butyl-4-hydroxyphenyl propionic acid isotridecyl ester), antioxidant 1098 (N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]), antioxidant 1135 (3,5-di-tert-butyl-4-hydroxyphenyl propionic acid isooctyl ester), and antioxidant 3114 (1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid-2,4,6-(1H,3H,5H)-trione). The first anti-yellowing aid is a radical trapping agent or a chelating agent, which mainly functions to trap / chelate free radicals (RO•, R•) generated by homolysis of molecular chains (such as ether bonds, urethane bonds) caused by heat / oxidation / light during high-temperature processing or long-term storage. The general formula of the trapped / chelated free radicals is as follows: for example, a hydrogen-donating type (using a phenol as an example) transfers a labile hydrogen to the free radical to generate a stable product. RO•+ ArOH → ROH + ArO• (The benzene ring in ArO• can form a conjugated system with the free radical, which increases the constraint on the electron and reduces the activity of the free radical, which cannot continue to initiate chain growth. Therefore, the use of the above first anti-yellowing aid can improve the yellowing resistance of the resin.

[0008] In some embodiments of the present application, the second anti-yellowing agent includes at least one of triphenyl phosphite, tris(nonylphenyl) phosphite, monooctyldiphenyl phosphite, triisooctyl phosphite, triisotridecyl phosphite, triisodecyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, dipentaerythritol diisodecyl phosphite, dipentaerythritol diisotridecyl phosphite, distearyl pentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphite, tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyldiphosphite, and poly(dipropylene glycol) phenylphosphite. The second anti-yellowing agent is a radical converter that converts or decomposes a free radical (such as ROO•) generated by homolysis of a molecular chain (such as an ether bond, a urethane bond) under heat / oxidation / light into a stable compound, as shown in the general formula: ROOH + P(OR')3→ ROH + (OR')3OP. The phosphoric acid ester or phosphite ester can quench the (excessive) peroxy radical that is not timely reacted in the high-temperature reaction, which can reduce the resin gel caused by excessive branching reaction and reduce the yellowing phenomenon of the resin. Therefore, the use of the above-mentioned second anti-yellowing agent can improve the yellowing resistance of the resin.

[0009] Further, the first anti-yellowing agent converts a free radical into an inert radical, and the second anti-yellowing agent directly converts a free radical into a stable compound. Through the synergistic effect of the first anti-yellowing agent and the second anti-yellowing agent, the yellowing resistance of the resin is significantly improved.

[0010] In some embodiments of the present application, the ultraviolet light stabilizer includes at least one of ultraviolet absorber UV-P (2-(2'-hydroxy-5'-methylphenyl) benzotriazole), ultraviolet absorber UV-1 (N-(p-ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine), ultraviolet absorber UV-328 (2-(3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole), ultraviolet absorber UV-312 (N-(2-ethoxyphenyl)-N'-(4-ethylphenyl)-oxalyl amide), ultraviolet absorber UV-571 (2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol), ultraviolet absorber UV-360 (2,2'-methylene-bis(6-benzotriazol-4-tert-octylphenyl phenol), ultraviolet absorber UV-3030 (pentaerythritol tetra(2-cyano-3,3-diphenyl acrylate), and ultraviolet absorber UV-3035 (2-cyano-3,3-diphenyl acrylate). The ultraviolet light stabilizer, such as benzotriazole, absorbs UV by converting light energy into heat energy through intramolecular hydrogen bonds: conjugated π bond ground state → excited state (after absorbing light energy) → molecular vibration relaxation (converted into heat energy for release), which can effectively reduce the generation of photoactive free radicals, thereby increasing the yellowing resistance of the resin composition. Therefore, the use of the above ultraviolet light stabilizer can effectively prolong the yellowing resistance of the product under sunlight (ultraviolet light).

[0011] In some embodiments of the present application, the first polymerization inhibitor includes at least one of a hydroquinone polymerization inhibitor, a benzoquinone polymerization inhibitor, and an alkoxyquinone polymerization inhibitor. The inventors have found that the use of the above-mentioned quinone compounds as the first polymerization inhibitor can form relatively stable hydrogen bonds with the phenolic substances in the first yellowing resistance aid, which can synergistically promote the capture and conversion of free radicals, thereby effectively improving the yellowing resistance of the resin.

[0012] As an example, the hydroquinone polymerization inhibitor includes hydroquinone, methylhydroquinone, tert-butylhydroquinone, and p-methoxyphenol, etc.

[0013] As an example, the benzoquinone polymerization inhibitor includes p-benzoquinone, methyl-p-benzoquinone, and tert-butyl-p-benzoquinone, etc.

[0014] As an example, the alkoxyquinone polymerization inhibitor includes p-methoxybenzoquinone, 4-methoxy-1,2-benzoquinone, 2,5-dimethoxy-1,4-benzoquinone, and 2-tert-butoxy-1,4-naphthoquinone.

[0015] In some embodiments of the present application, the diisocyanate includes at least one of hexamethylene diisocyanate, isophorone diisocyanate, trimethylhexane diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethane diisocyanate.

[0016] In some embodiments of the present application, the polyhydroxycarboxylic acid comprises at least one of dihydroxymethylpropionic acid, dihydroxymethylbutyric acid, gluconic acid, citric acid, tartaric acid, and malic acid.

[0017] In some embodiments of the present application, the acid anhydride comprises at least one of phthalic anhydride, maleic anhydride, succinic anhydride (butanedioic anhydride), tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, pyromellitic dianhydride, methyl nadic anhydride, and camphoric anhydride.

[0018] In some embodiments of the present application, the polyurethane resin composition comprises 100-125 parts by weight of the phenolic epoxy acrylic resin, 68.4-159.6 parts by weight of the diisocyanate, 27.0-43.9 parts by weight of the polyhydroxycarboxylic acid, 0.01-2.5 parts by weight of the first polymerization inhibitor, 38.2-96.6 parts by weight of the acid anhydride, and 0.3-5.0 parts by weight of the first anti-yellowing component. Due to the high activity of the -NCO (isocyanate group) of the diisocyanate, it reacts with the active hydroxyl groups in the phenolic epoxy acrylic resin or the polyhydroxycarboxylic acid under the action of a catalyst to form a urethane bond (-NHCOO-), forming a linear or branched prepolymer, which builds the polyurethane main chain, providing flexibility and mechanical strength; and reacts with the polyhydroxymethyl carboxylic acid (-COOH) to form an amide structure, accompanied by the release of a small amount of CO2. When the carboxyl groups in the reaction system are substantially completely reacted (the acid value is reduced to below 1.5 mg KOH / g, but not zero), the added acid anhydride undergoes nucleophilic substitution reaction with the (-OH) in the phenolic epoxy acrylic resin to form ester groups and carboxyl groups, obtaining a resin composition containing both vinyl groups and carboxyl groups. The weight parts of each material of the polyurethane resin preparation raw materials are within the above range, further improving the yellowing resistance of the resin.

[0019] In some embodiments of the present application, the preparation raw materials of the phenolic epoxy acrylic resin comprise 100-135 parts by weight of the epoxy resin, 35.7-70 parts by weight of the (meth)acrylic compound, 0.2-4.0 parts by weight of the catalyst, 0.1-1.5 parts by weight of the second polymerization inhibitor, and 0-3.0 parts by weight of the second anti-yellowing component. Under the action of the acidic catalyst, the carboxyl groups (-COOH) in the acrylic acid catalyze the ring opening of the epoxy groups to form ester bonds and hydroxyl groups, and the second polymerization inhibitor can prevent the free radicals generated during the reaction from causing excessive polymerization to initiate gelation. The inventors have found that the weight parts of each material of the preparation raw materials of the phenolic epoxy acrylic resin are within the above range, further improving the yellowing resistance of the resin.

[0020] In some embodiments of the present application, the (meth)acrylic compound includes, but is not limited to, acrylic acid, methacrylic acid, and the like.

[0021] The second polymerization inhibitor includes at least one of a hydroquinone-based polymerization inhibitor, a benzoquinone-based polymerization inhibitor, and an alkoxyquinone-based polymerization inhibitor.

[0022] In some embodiments of the present application, the epoxy resin includes at least one of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and an ortho-cresol formaldehyde resin.

[0023] In some embodiments of the present application, the catalyst includes at least one of an organic amine-based catalyst, a triphenylphosphine-based catalyst, and an organic ammonium salt and derivative thereof-based catalyst.

[0024] As an example, the organic amine-based catalyst includes at least one of triethylamine, N,N-dimethylaniline, N,N-dimethylbenzylamine, N,N'-dimethylpyridine, 2,6-dimethylpyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, triethylenediamine, N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl)ether, N,N,N',N'-tetramethylethylenediamine, and a substituted group-containing organic amine-based catalyst.

[0025] As an example, the triphenylphosphine-based catalyst includes at least one of triphenylphosphine, tri(o-tolyl)phosphine, tri(m-tolyl)phosphine, tri(p-tolyl)phosphine, tri(p-methoxyphenyl)phosphine, tri(2,6-dimethoxyphenyl)phosphine, p-styryldiphenylphosphine, and 4-(dimethylamino)triphenylphosphine.

[0026] As an example, the organic ammonium salt and derivative thereof-based catalyst includes at least one of tetraethylammonium bromide, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, benzyltriethylammonium chloride, dodecyltrimethylammonium chloride, and alkyl dimethyl benzyl ammonium chloride.

[0027] In some embodiments of the present application, the second polymerization inhibitor is the same as or different from the first polymerization inhibitor.

[0028] In some embodiments of the present application, the second anti-yellowing component is the same as or different from the first anti-yellowing component.

[0029] In a second aspect of the present application, a method of preparing the polyurethane resin composition described above is provided. According to embodiments of the present application, the method includes: (1) mixing and reacting an epoxy resin, a (meth)acrylic compound, a catalyst, a second polymerization inhibitor, and a second anti-yellowing component to prepare a phenolic epoxy-acrylic resin; (2) reacting the phenolic epoxy-acrylic resin, a polyhydroxycarboxylic acid, a first polymerization inhibitor, a first anti-yellowing component, and a diisocyanate in the presence of a solvent; (3) adding an acid anhydride reaction to the reaction system of step (2), after the reaction is completed, continuously adding the first anti-yellowing component to react at 60-80°C, to obtain the polyurethane resin composition.

[0030] First, the epoxy resin, the (meth)acrylic compound, the catalyst, the second polymerization inhibitor and the second anti-yellowing component are mixed and reacted to prepare a phenolic epoxy acrylate resin. The second anti-yellowing component is added in the preparation process of the phenolic epoxy acrylate resin, which can control the reaction speed of free radicals in the reaction process together with the second polymerization inhibitor, reduce the interference of residual oxygen in the reaction system on the reaction, effectively inhibit yellowing and avoid the occurrence of gel. Then, the phenolic epoxy acrylate resin, the polyhydroxy carboxylic acid, the first polymerization inhibitor, the first anti-yellowing component and the diisocyanate are reacted in the presence of a solvent. The urethane and amide bonds are easily decomposed by heat. The addition of the first anti-yellowing component can further inhibit yellowing. Finally, an acid anhydride reaction is added to the above reaction system, after the reaction is completed, continuously adding the first anti-yellowing component to react at constant temperature, to obtain the polyurethane resin. After the reaction is completed, continuously adding the first anti-yellowing component can avoid yellowing of the resin during storage and prolong the storage time. The inventors found that compared with adding the anti-yellowing component at one time, adding the anti-yellowing component in steps (1) to (3) can inhibit the yellowing problem that may occur in each reaction process, maximally inhibit the yellowing of the resin, and does not affect the synthesis effect of the resin.

[0031] In some embodiments of the present application, the first polymerization inhibitor and the second polymerization inhibitor in steps (1) and (2) respectively independently comprise at least one of a hydroquinone polymerization inhibitor, a benzoquinone polymerization inhibitor and an alkoxyquinone polymerization inhibitor. Preferably, the first polymerization inhibitor and the second polymerization inhibitor are the same.

[0032] In some embodiments of the present application, the solvent comprises one or more of toluene, ethylbenzene, isophorone, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol methyl ether acetate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, butyl acetate, isoamyl acetate, cyclohexanone. Further, the preferred solvent is selected from any one or more of propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate. In some embodiments of the present application, the mass ratio of the second anti-yellowing component of step (1), the first anti-yellowing component of step (2), and the first anti-yellowing component of step (3) is (0.1-3.0):(0.1-1.5):(0.05-0.5). The inventors have found that too little anti-yellowing component cannot reduce the generation of free radicals or effectively convert excess free radicals, resulting in weakened anti-yellowing effect; when there is too much anti-yellowing component, too many free radicals are converted or quenched, which has a certain inhibitory effect on the reaction effect, on the one hand, it will prolong the reaction time and increase the cost; secondly, it will increase the side reaction and affect the synthesis effect of the resin. Therefore, controlling the mass ratio of the second anti-yellowing component of step (1), the first anti-yellowing component of step (2), and the first anti-yellowing component of step (3) within the above range can maximize the effect of the anti-yellowing component and improve the anti-yellowing ability of the resin.

[0033] In some embodiments of the present application, the reaction temperature in step (1) is 90-100°C, and the reaction is carried out in the dark under nitrogen protection until the solid acid value is less than 1.5 mg KOH / g, to obtain a phenolic epoxy acrylic resin.

[0034] In some embodiments of the present application, in step (1), the mass ratio of the second polymerization inhibitor and the first anti-yellowing aid in the second anti-yellowing component is 1:(0.65-20). The anti-yellowing aid inhibits the generation of free radicals or captures and converts free radicals, and the phenols in the anti-yellowing aid and the phenols or quinones in the second polymerization inhibitor can form hydrogen bonds to form a 'net-like' structure. In step (1), the mass ratio of the second polymerization inhibitor and the first anti-yellowing aid in the second anti-yellowing component within the above range can better capture and convert free radicals, and has better anti-yellowing effect.

[0035] In some embodiments of the present application, in step (2), the phenolic epoxy acrylic resin obtained in step (1) is cooled to 55-65°C, and then a polyhydroxy carboxylic acid, a first polymerization inhibitor, a first anti-yellowing component, and a solvent are added and dissolved uniformly, and then a diisocyanate is added until the characteristic peak of isocyanate disappears in infrared monitoring.

[0036] In some embodiments of the present application, in step (2), the mass ratio of the first polymerization inhibitor and the first anti-yellowing aid in the first anti-yellowing component is 1:(2-30). The inventors have found that in step (2), the mass ratio of the first polymerization inhibitor and the first anti-yellowing aid in the first anti-yellowing component within the above range can better capture and convert free radicals, and has better anti-yellowing effect.

[0037] In some embodiments of the present application, in step (3), after the disappearance of the isocyanate characteristic peak is monitored by infrared in step (2), the reaction is continued at 75℃-85℃, and the acid anhydride is added in two batches, the reaction is stopped until the acid anhydride peak disappears, and then the first anti-yellowing component and the solvent are added, and the constant temperature stirring is continued for 0.5-4 h, to obtain the polyurethane resin.

[0038] In a third aspect of the present application, the present application provides the use of the above-mentioned polyurethane resin composition or the polyurethane resin composition prepared by the above-mentioned method in the fields of aerospace, ship transportation, medical devices or electrical and electronic information.

[0039] The present application has at least the following technical effects: (1) The present application can effectively capture and convert free radicals generated during the reaction by the combined action of the first anti-yellowing agent, the second anti-yellowing agent and the ultraviolet light stabilizer, thereby significantly reducing the yellowing degree of the resin.

[0040] (2) The first polymerization inhibitor used in the present application is a quinone compound, which can form a relatively stable hydrogen bond with the phenolic substance in the first anti-yellowing agent, thereby synergistically promoting the capture and conversion of free radicals and effectively improving the anti-yellowing effect of the resin.

[0041] (3) In the process of preparing the polyurethane resin composition of the present application, anti-yellowing components are added in each step, thereby significantly improving the anti-yellowing performance of the resin. DETAILED DESCRIPTION

[0042] All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative labor are within the scope of protection of the present application. The present application will be described below with reference to specific embodiments, and it should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0043] If the specific technology or conditions are not specified in the embodiments, the technology or conditions described in the literature in the art or according to the product manual are used. If the reagents or instruments are not specified by the manufacturer, they are conventional products that can be purchased through regular channels.

[0044] Example 1 A method for preparing a polyurethane resin composition, comprising the following steps: (1) 100 parts of a commercially available bisphenol F type epoxy resin, 46.05 parts of methacrylic acid, 0.4 parts of a catalyst (triphenylphosphine), 0.15 parts of a second polymerization inhibitor (2,6-di-tert-butyl-p-cresol), and 2 parts of a second anti-yellowing component are sequentially added into a reaction kettle, and the temperature is raised to 95°C in the dark under nitrogen protection. When the solid acid value is less than 1.5 mg KOH / g, an epoxy-acrylic resin composition is obtained.

[0045] The second anti-yellowing component is composed of antioxidant 1077, tetraphenyl dipropylene glycol diphosphite, and ultraviolet absorber-571 at a mass ratio of 1:2:1.

[0046] (2) The epoxy-acrylic resin composition obtained in step (1) is cooled to 60°C, and then 30 parts of dimethylol propionic acid, 0.05 parts of a first polymerization inhibitor (2,6-di-tert-butyl-p-cresol), 1 part of a first anti-yellowing component, and 45.2 parts of a solvent are sequentially added. After stirring and dissolving uniformly, 56.1 parts of trimethyl hexamethylene diisocyanate is added dropwise. After the infrared monitoring shows that the isocyanate characteristic peak completely disappears.

[0047] The first anti-yellowing component used in step (2) is the same as the second anti-yellowing component used in step (1).

[0048] (3) The temperature is continuously raised to 80°C, and then 20.5 parts of succinic anhydride is added in two batches. The reaction is stopped until the anhydride peak completely disappears. Then, 0.25 parts of the first anti-yellowing component and 22.6 parts of a solvent are added, and constant temperature stirring is continued for 2 hours to obtain a polyurethane resin composition.

[0049] The first anti-yellowing component used in step (2) is the same as the first anti-yellowing component used in step (1).

[0050] Example 2 A method for preparing a polyurethane resin composition, which is different from that of Example 1 only in that: The first anti-yellowing component and the second anti-yellowing component are composed of antioxidant 1077, tetraphenyl dipropylene glycol diphosphite, and ultraviolet absorber-571 at a mass ratio of 1.0:5.0:0.5.

[0051] Example 3 A method for preparing a polyurethane resin composition, which is different from that of Example 1 only in that: The first anti-yellowing component and the second anti-yellowing component are composed of antioxidant 1077 and tetraphenyl dipropylene glycol diphosphite at a mass ratio of 1.0:5.0.

[0052] Example 4 A method for preparing a polyurethane resin composition, which is different from that of Example 1 only in that: The first anti-yellowing component and the second anti-yellowing component are composed of antioxidant 1077, tetraphenyl dipropylene glycol diphosphite and ultraviolet absorber-571 in a mass ratio of 1.0:0.1:5.0.

[0053] Example 5 A preparation method of a polyurethane resin composition, the steps of which are only different from those of Example 1 in that: The mass fraction of the first polymerization inhibitor in step (2) is 0.025 parts.

[0054] Example 6 A preparation method of a polyurethane resin composition, the steps of which are only different from those of Example 1 in that: The mass fraction of the first polymerization inhibitor in step (2) is 1.25 parts.

[0055] Example 7 A preparation method of a polyurethane resin composition, the steps of which are only different from those of Example 1 in that: The weight fractions of the anti-yellowing components in steps (1) to (3) in Example 7 are 0.1 parts, 0.1 parts and 0.05 parts, respectively.

[0056] Example 8 A preparation method of a polyurethane resin composition, the steps of which are only different from those of Example 1 in that: The weight fractions of the anti-yellowing components in steps (1) to (3) in Example 7 are 3 parts, 1.5 parts and 0.5 parts, respectively.

[0057] Example 9 A preparation method of a polyurethane resin composition, the steps of which are only different from those of Example 1 in that: The first anti-yellowing component and the second anti-yellowing component are composed of antioxidant 1135, pentaerythritol diisodecyl diphosphite and ultraviolet absorber UV-312 in a mass ratio of 1:2:1.

[0058] Example 10 A preparation method of a polyurethane resin composition, the steps of which are only different from those of Example 1 in that: Both the second polymerization inhibitor in step (1) and the first polymerization inhibitor in step (2) in Example 10 are p-benzoquinone.

[0059] Comparative Example 1 A preparation method of a polyurethane resin composition, the steps of which are only different from those of Example 1 in that: No first anti-yellowing component or second anti-yellowing component is added in steps (1) to (3) in Comparative Example 1.

[0060] Comparative Example 2 A method for preparing a polyurethane resin composition, the steps of which differ from those of Example 1 only in that: The first and second anti-yellowing components of Step (1) to Step (3) of Comparative Example 2 are both antioxidant 1077.

[0061] Comparative Example 3 A method for preparing a polyurethane resin composition, the steps of which differ from those of Example 1 only in that: The first and second anti-yellowing components of Step (1) to Step (3) of Comparative Example 3 are both tetraphenyl dipropylene glycol diphosphite.

[0062] Comparative Example 4 A method for preparing a polyurethane resin composition, the steps of which differ from those of Example 1 only in that: The first and second anti-yellowing components of Step (1) to Step (3) of Comparative Example 4 are both UV absorber-571.

[0063] The anti-yellowing performance of the resins prepared in the examples and comparative examples was tested according to the following method: The anti-yellowing effect was obtained from the tin soldering test, and the experimental conditions were as follows: A 1-2 mm thick layer of the alkali-soluble polyurethane resin composition was uniformly coated on a copper foil, and a small amount of solvent was removed in a vacuum oven at 100°C for 10-20 min; the test was performed under a white light lamp (a common source of ultraviolet light), at an oxygen content of about 21% (the average oxygen content in the atmosphere), and at a tin furnace temperature of 280°C (common extreme high temperature test conditions); the copper foil was placed in the tin furnace for 5 min, 10 min, 30 min, and 2 h, and the yellowing of the alkali-soluble polyurethane resin was observed.

[0064] The results of the anti-yellowing performance test of the resins prepared in the examples and comparative examples are shown in Table 1.

[0065] Table 1

[0066] Transparent and no yellowing: √; slight yellowing: ◎; moderate yellowing: □; severe yellowing: ×; no qualified product: —.

[0067] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art will understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A polyurethane resin composition, characterized by, The composition comprises: a phenolic epoxy acrylic resin, a diisocyanate, a polyhydroxy carboxylic acid, a first polymerization inhibitor, an acid anhydride, and a first anti-yellowing component; The first anti-yellowing component comprises a first anti-yellowing aid, a second anti-yellowing aid, and an ultraviolet light stabilizer, and the mass ratio of the first anti-yellowing aid, the second anti-yellowing aid, and the ultraviolet light stabilizer is 1.0: (0.1-5.0): (0-5.0); The mass ratio of the first polymerization inhibitor to the first anti-yellowing aid in the first anti-yellowing component is 1.0: (0.2-10).

2. The polyurethane resin composition according to claim 1, characterized by The first anti-yellowing aid comprises at least one of butyl methoxyphenol, di-tert-butyl-p-cresol, tert-butyl hydroquinone, n-octyl gallate, antioxidant 1010, antioxidant 1024, antioxidant 1035, antioxidant 1076, antioxidant 1077, antioxidant 1098, antioxidant 1135, and antioxidant 3114; And / or, the second anti-yellowing aid comprises at least one of triphenyl phosphite, tris(nonylphenyl) phosphite, monooctyldiphenyl phosphite, triisooctyl phosphite, triisotridecyl phosphite, triisodecyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, dipentaerythritol diisodecyl diphosphite, dipentaerythritol diisotridecyl diphosphite, distearyl pentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphite, tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite, and poly(dipropylene glycol) phenyl phosphite; And / or, the ultraviolet light stabilizer comprises at least one of ultraviolet absorber UV-P, ultraviolet absorber UV-1, ultraviolet absorber UV-328, ultraviolet absorber UV-312, ultraviolet absorber UV-571, ultraviolet absorber UV-360, ultraviolet absorber UV-571, ultraviolet absorber UV-3030, and ultraviolet absorber UV-3035; And / or, the first polymerization inhibitor comprises at least one of a hydroquinone-based polymerization inhibitor, a benzoquinone-based polymerization inhibitor, and an alkoxyquinone-based polymerization inhibitor; And / or, the diisocyanate comprises at least one of hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, trimethylhexane diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethane diisocyanate; And / or, the polyhydroxy carboxylic acid comprises at least one of bis-hydroxymethyl propionic acid, dihydroxymethyl butyric acid, gluconic acid, citric acid, tartaric acid, and malic acid; And / or, the acid anhydride comprises at least one of phthalic anhydride, maleic anhydride, succinic anhydride (butanedioic anhydride), tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, pyromellitic dianhydride, methyl nadic anhydride, and camphoric anhydride.

3. The polyurethane resin composition according to claim 1, characterized by The phenolic epoxy acrylic resin is prepared from 100-135 parts of an epoxy resin, 35.7-70 parts of a (meth)acrylic compound, 0.2-4.0 parts of a catalyst, 0.1-1.5 parts of the second polymerization inhibitor, and 0-3.0 parts of the second anti-yellowing component.

4. The polyurethane resin composition according to claim 3, characterized by The phenolic epoxy acrylic resin is prepared from 100-135 parts of an epoxy resin, 35.7-70 parts of a (meth)acrylic compound, 0.2-4.0 parts of a catalyst, 0.1-1.5 parts of the second polymerization inhibitor, and 0-3.0 parts of the second anti-yellowing component.

5. The polyurethane resin composition according to claim 4, characterized by The epoxy resin comprises at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and o-cresol formaldehyde resin; The catalyst comprises at least one of organic amine catalyst, triphenylphosphine catalyst, and organic ammonium salt and its derivative catalyst; The second polymerization inhibitor is the same as or different from the first polymerization inhibitor. The second anti-yellowing component is the same as or different from the first anti-yellowing component.

6. A method for producing the polyurethane resin composition according to any one of claims 1 to 5, characterized by, The method comprises: (1) mixing the epoxy resin, the (meth)acrylic compound, the catalyst, the second polymerization inhibitor, and the second anti-yellowing component to prepare the phenolic epoxy acrylic resin; (2) reacting the phenolic epoxy acrylic resin, the polyhydroxycarboxylic acid, the first polymerization inhibitor, the first anti-yellowing component, and the diisocyanate in the presence of a solvent; (3) adding the acid anhydride to the reaction system of step (2) and continuing to add the first anti-yellowing component at 60-80°C to prepare the polyurethane resin composition.

7. The method of claim 6, wherein the first polymerization inhibitor and the second polymerization inhibitor in step (1) and step (2) are independently selected from at least one of hydroquinone polymerization inhibitor, benzoquinone polymerization inhibitor, and alkoxyquinone polymerization inhibitor. Preferably, the first polymerization inhibitor is the same as the second polymerization inhibitor.

8. The preparation method according to claim 6, characterized in that, The mass ratio of the second anti-yellowing component in step (1), the first anti-yellowing component in step (2), and the first anti-yellowing component in step (3) is (0.1-3.0):(0.1-1.5):(0.05-0.5). Preferably, the second anti-yellowing component comprises a first anti-yellowing aid, a second anti-yellowing aid, and an ultraviolet light stabilizer, and the mass ratio of the first anti-yellowing aid, the second anti-yellowing aid, and the ultraviolet light stabilizer is 1.0:(0.1-5.0):(0-5.0).

9. The production method according to claim 8, characterized by, In step (1), the mass ratio of the second polymerization inhibitor to the first anti-yellowing aid in the second anti-yellowing component is 1:(0.65-20). In step (2), the mass ratio of the first polymerization inhibitor to the first anti-yellowing aid in the first anti-yellowing component is 1:(2-30).

10. The polyurethane resin composition of any one of claims 1-5 or prepared by the method of any one of claims 6-9 for use in the fields of aerospace, marine transportation, medical devices, or electrical and electronic information.

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