High heat resistant and high scratch resistant water-based polyurethane and manufacturing method thereof

Abstract

A method for manufacturing high heat resistant and high scratch resistant water-based polyurethane, which can improve the mechanical strength and water resistance of water-based polyurethane by using acrylate graft modification, is provided. In particular, 2-hydroxyethyl acrylate (2-HEA), methyl methacrylate (MMA), ethyl acrylate (EA), acrylic acid (AA), glycidyl methacrylate (GMA) and triallyl isocyanuric acid ester (TAIC) are used to dilute polyurethane prepolymer. As a result, the prepolymer has a good dispersing effect, and further, waterborne bridging agent and cellulose nanofiber are added to the water-based polyurethane to obtain water-based polyurethane which has high heat resistance and scratch resistance.

Claims

1. A method for manufacturing high heat resistant and high scratch resistant water-based polyurethane, based on the total amount in weight of a reactive material of a polyurethane prepolymer, adding 10 to 30 wt % of acrylic monomer to dilute the polyurethane prepolymer so as to synthesize water-based polyurethane, and then adding initiator to make acrylic graft modification water-based polyurethane, wherein the acrylic monomer is a combination of the following six monomers: 3-9 wt % of 2-hydroxyethyl acrylate (2-HEA), 80-90 wt % of methyl methacrylate (MMA), 2-10 wt % of ethyl acrylate (EA), 0.5-5 wt % of acrylic acid (AA), 0.1-2 wt % of glycidyl methacrylate (GMA) and 0.1-2 wt % of triallyl isocyanurate (TAIC).

2. The method for manufacturing the high heat resistant and high scratch resistant water-based polyurethane according to claim 1, wherein 3-9 wt % of waterborne bridging agent is added to the acrylic graft modification water-based polyurethane based on the total amount in weight of the acrylic graft modification water-based polyurethane.

3. The method for manufacturing the high heat resistant and high scratch resistant water-based polyurethane according to claim 1, wherein 3-9 wt % of waterborne bridging agent and 0.1-2 wt % cellulose nanofiber (CNF) is added to the acrylic graft modification water-based polyurethane based on the total amount in weight of the acrylic graft modification water-based polyurethane.

4. The method for manufacturing the high heat resistant and high scratch resistant water-based polyurethane according to claim 1, wherein the acrylic monomer is a combination of the following six monomers based on the total amount in weight of the acrylic monomer: (a) methyl methacrylate 82 wt %; (b) 2-hydroxyethyl acrylate 6 wt %; (c) ethyl acrylate 6 wt %; (d) acrylic acid 3 wt %; (e) glycidyl methacrylate 1.5 wt %; and (f) triallyl isocyanurate 1.5 wt %.

5. The method for manufacturing the high heat resistant and high scratch resistant water-based polyurethane according to claim 3, wherein the cellulose nanofiber (CNF) is selected from cellulose nanofiber having a fiber diameter of 3 nm to 10 nm and a fiber length of 100 nm to 3 m.

6. A high heat resistant and high scratch resistant water-based polyurethane, manufactured by using the method of claim 1.

Description

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

(1) The present disclosure is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Like numbers in the drawings indicate like components throughout the views. As used in the description herein and throughout the claims that follow, unless the context clearly dictates otherwise, the meaning of a, an, and the includes plural reference, and the meaning of in includes in and on. Titles or subtitles can be used herein for the convenience of a reader, which shall have no influence on the scope of the present disclosure.

(2) The terms used herein generally have their ordinary meanings in the art. In the case of conflict, the present document, including any definitions given herein, will prevail. The same thing can be expressed in more than one way. Alternative language and synonyms can be used for any term(s) discussed herein, and no special significance is to be placed upon whether a term is elaborated or discussed herein. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms is illustrative only, and in no way limits the scope and meaning of the present disclosure or of any exemplified term. Likewise, the present disclosure is not limited to various embodiments given herein. Numbering terms such as first, second or third can be used to describe various components, signals or the like, which are for distinguishing one component/signal from another one only, and are not intended to, nor should be construed to impose any substantive limitations on the components, signals or the like.

(3) Water-based polyurethane synthesis method of the present disclosure is carried out by a four-stage polymerization of a polyurethane resin modified by an acrylic graft modification. This synthetic method not only facilitates the synthesis of solvent-free water-based polyurethane, but also achieves the effect of acrylic graft modification. The water-based polyurethane synthesis method of the present disclosure includes the following steps:

(4) 1. Preparation of Prepolymer:

(5) The prepolymer is synthesized by an urethanization reaction between polyhydric alcohol and diisocyanate; preferably, the NCO theoretical equivalent ratio (NCO/OH) of the prepolymer is from 1.1 to 2.7. The polypolyol is selected from polyester polyol, polyether polyol, polycarbonate polyol and polyester decylamine polyol; the diisocyanate is selected from aliphatic diisocyanate, alicyclic diisocyanate and modified form thereof, and may be used singly or in combination of two or more.

(6) The polyester polyol is prepared by condensation of low molecular weight diol and dicarboxylic acid. The diol is selected from ethyleneglycol, 1,3-propanediol and 1,4-butanediol; the dicarboxylic acid is selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid and cyclohexanedicarboxylic acid.

(7) The polyester decylamine polyol is an amine polyester decylamine polyol selected from hexamethylenediamine or isophorone diamine.

(8) Each of the above polyols may be used singly or in combination of several or as copolymer thereof.

(9) The polyether polyol is selected from polytetramethylene etherglycol (PTMG), polypropyleneglycol (PPG) and polyether polyol whose main chain and side chain are polyethyleneglycol (PEG).

(10) The aliphatic diisocyanate is selected from tetramethylene diisocyanate, hexamethylene diisocyanate, decamethylene diisocyanate and lysine diisocyanate; preferably hexamethylene diisocyanate.

(11) The alicyclic diisocyanate is selected from isophorone diisocyanate, hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate and tetramethylxylene diisocyanate; preferably isophorone diisocyanate.

(12) The urethane modified body of the aliphatic diisocyanate or the alicyclic diisocyanate is selected from a carbodiimide modified body, an allophanate modified body, a urea modified body, a biuret modified body, an uretodion modified body, an uretonimine modified form, and an isocyanurate modified form.

(13) The diisocyanate may also be substituted with aromatic polyisocyanate or aromatic diisocyanate. The aromatic polyisocyanate is selected from polyphenylene polymethylene polyisocyanate and unrefined tolylene diisocyanate.

(14) The aromatic diisocyanate is selected from 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, 4,4-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4-diisocyanate, 2,2-diphenylpropane-4,4-diisocyanate, 3,3-dimethyldiphenylmethane-4,4-diisocyanate, 4,4-diphenylpropane diisocyanate, isophthalic diisocyanate, P-phenylene diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate and 3,3-dimethoxydiphenyl-4,4-diisocyanate.

(15) The present disclosure uses low molecular polyol and the diisocyanate for urethane reaction. The low molecular polyol is selected from ethyleneglycol, 1,3-propanediol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentylglycol, 1,8-octanediol, 1,9-nonanediol, 3,3-dimethylol heptane, diethyleneglycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-ethyl-1,3-propanediol, 2-n-propyl-1,3-propanediol, 2-isopropyl-1,3-propanediol, 2-n-butyl-1,3-propanediol, 2-isobutyl-1,3-propanediol, 2-tert-butyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-propyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-3-ethyl-1,4-butanediol, 2-methyl-3-ethyl-1,4-butanediol, 2,3-diethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol and 2,3,4-triethyl-1,5-pentanediol; or selected from trimethylolpropane, dimethylolpropionic acid, dimethylolbutanoic acid, dibasic acid diol, glycerin, pentaerythritol and bisphenol A.

(16) 2. Dilution and Chain Extension of the Prepolymer:

(17) The acrylic monomer may be an acrylate monomer selected from one or any combination of methyl acrylate, methyl methacrylate (MMA), ethyl acrylate (EA), isooctyl acrylate, butyl acrylate, butyl methacrylate, ethyl hexyl acrylate, and 2-hydroxyethyl acrylate (2-HEA); further, monomethyl maleate, monomethyl itaconate, monomethyl fumarate, styrene, acrylic acid (AA), glycidyl methacrylate (GMA), triallyl isocyanurate (TAIC) and mixtures thereof replace acrylate monomers can also be adopted.

(18) Preferably, six acrylic monomers 2-hydroxyethyl acrylate (2-HEA), methyl methacrylate (MMA), ethyl acrylate (EA), acrylic acid (AA), glycidyl methacrylate (GMA), and triallyl isocyanurate (TAIC) are in combination, so as to achieve the effect of complementary of physical properties and has solvent effect. In particular, the combination of these six acrylic monomers has a solvent effect, and does not require the use of a large amount of acetone, the synthesis reaction yield can be greatly increased, and the production cost is effectively reduced.

(19) The water-based polyurethane synthesis method of the present disclosure is that, after the prepolymer is reacted for 2-3 hours, the above-mentioned six kinds of monomers are added, the solvent dispersion effect can be exerted, and the graft polymerization is carried out in the acrylic synthesis stage. The effects of the six monomers are as follows: (1) 2-hydroxyethyl acrylate (2-HEA) contains a hydroxyl group (OH) and can react with isocyanate; (2) Methyl methacrylate (MMA) and ethyl acrylate (EA) can increase the acrylic molecular weight so as to compensate for the disadvantages of poor heat resistance and low mechanical strength of polyurethane; (3) Acrylic acid (AA), also known as acrylic acid, is an organic compound of the chemical formula C.sub.3H.sub.4O.sub.2. It is the simplest unsaturated carboxylic acid, and consists of a vinyl group and a carboxyl group, which can react with carboxylic acids, and a corresponding ester can also be obtained by reacting with an alcohol; when acrylic acid and its esters are mixed with other monomers, polymerization will occur to form a homopolymer or copolymer; (4) Glycidyl methacrylate (GMA) has a vinyl group and an epoxy ring, which can react differently, and then use a radical to open a double bond to form an epoxy ring linear polymer with other acrylic monomers; the epoxy ring is cross-linked with the carboxylic acid in the system under the catalysis of an acid or an amine; and (5) Triallyl isocyanurate (TAIC) is a multifunctional olefin monomer containing aromatic heterocyclic ring, which can be homopolymerized and cross-linked with various olefins, so as to improve the heat resistance and mechanical strength of the polyurethane, and achieve excellent physical properties and solvent effect; in addition, because a large amount of acetone is not used, the synthesis reaction yield can be greatly increased, and the production cost is effectively reduced.

(20) Based on the total amount in weight of the acrylic monomer, the combination ratio of six kinds of acrylic monomers of 2-HEA, MMA, EA, AA, gMA and TAIC is as follows: 1) methyl methacrylate (MMA) 80-90 wt %; 2) 2-hydroxyethyl acrylate (2-HEA) 3-9 wt %; 3) ethyl acrylate (EA) 2-10 wt %; 4) acrylic acid (AA) 0.5-5 wt %; 5) glycidyl methacrylate (GMA) 0.1-2 wt %; 6) triallyl isocyanurate (TAIC) 0.1-2 wt %

(21) A combination of methyl methacrylate 82 wt %, 2-hydroxyethyl acrylate 6 wt %, ethyl acrylate 6 wt %, acrylic acid 3 wt %, glycidyl methacrylate 1.5 wt % and triallyl isocyanurate 1.5 wt % is particularly preferred.

(22) In order to extend the prepolymer chain, the present disclosure uses a sulfonate chain extender, which is not only used as hydrophilic agent for polyurethanes, but also as polymeric emulsifier in an amount of 80-90% of the theoretical equivalent ratio of NCO (NCO/OH). The sulfonate chain extender is selected from sodium ethylenediamine sulfonate (AAS), sodium 2,4-diaminobenzenesulfonate, sodium 3,5-diaminobenzenesulfonate (DABS), 1,4-butanediol-2-sulfonate sodium, sodium 1,2-dihydroxy-3-propane sulfonate and sodium N,N-dihydroxyethylamine ethylsulfonate; preferably AAS or DABS.

(23) 3. Water Dispersion:

(24) After the obtained polymer is dispersed in water, a metered water-soluble diamines chain extender is added to carry out a chain extension reaction; The chain extender is selected from a low molecular polyamine having a (number average) molecular weight of less than 500, including ethylenediamine, hexamethylenediamine, xylenediamine, isophoronediamine, diethylenetriamine or N-Aminoethyl-N-ethanolamine; and the chain extender is used in an amount of (NCO/OH) equivalent of 10% to 20%.

(25) 4. Acrylic Synthesis:

(26) A sulfonate-type water-based polyurethane of the above-mentioned step is added with an emulsifier of 0.3 to 1.0 wt % to form an emulsion, and the temperature is raised to 50-70 C., and then 0.01 to 0.10 wt % of a initiator is added dropwise to carry out polymerization of the acrylate. The temperature is further increased to 75-85 C., and maintained for 1-3 hours, then lowered to 50-70 C., and then the reducing agent is added 0.01-0.08 wt % to obtain an acrylic graft modification water-based polyurethane.

(27) Emulsifier is a kind of surfactant, which can greatly reduce the surface tension, and transform the mutually incompatible two-phase oil-water into a white emulsion. The white emulsion is an essential component of emulsion polymerization which can be stably existed and is not easy to be layered by stirring. The emulsifier may be a mixture of one or more of an anionic, a nonionic or a reactive emulsifier.

(28) The anionic emulsifier is selected from sodium dodecyl sulfate (SLS), sodium dodecyl benzene sulfonate, potassium stearate, sodium dioctyl sulfosuccinate, sodium dodecyl dibenzoate disulfonate, nonylbenzene oxyethyl poly(1) ammonium ethoxide sulfate, sodium styrene sulfonate, sodium lauryl allysulphosuccinate, linseed oil fatty acid, sodium or ammonium salt of ethoxylated nonylphenol phosphate, octoxynol 3-sulfonate sodium, sodium cocoyl sarcosinate, sodium 1-alkoxy-2-hydroxypropyl sulfonate, sodium -olefin (C14-C16) sulfonate, hydroxyl Sulfate of alkanol, tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinic acid, disodium N-octadecylsulfosuccinamide, alkane disodium sulphate polyethoxy sulfosuccinate, disodium ethoxylated succinyl sulfosuccinate and sodium ethoxyethyl sulfate. The amount of the emulsifier is 3 wt % or less based on the total amount of the acrylate monomer, and is 0.3-1.0 wt % based on the total amount in weight of the reactive material.

(29) The nonionic or reactive emulsifier includes teoctylphenoxyethyl poly(39)-ethoxyethanol, dodecyloxypoly (10) ethoxyethanol, nonylphenoxyethyl-poly (40) ethoxyethanol, polyethyleneglycol 2000 monooleate, hydroxyethylated castor oil, fluorinated alkyl esters and alkoxides, polyoxyethylene (20) sucrose monolaurate, sucrose cocoate, bis(2-butyl)phenoxypoly (20) ethoxyethanol and hydroxyethylcellulose butyl acrylategraft copolymer.

(30) The initiator is preferably a water-soluble free radical initiator selected from hydrogen peroxide, tert-butyl peroxide and alkali metal persulfate; or selected from sodium persulfate, potassium persulfate, lithium persulfate and ammonium sulfate (APS); the amount of the initiator is 0.01-3 wt % based on the total amount in weight of the acrylate monomer, and is 0.01-0.10 wt % based on the total amount in weight of the reactive material.

(31) In the late stage of emulsion polymerization, in order to avoid emulsion agglomeration caused by heating, post-removal of the monomer can be carried out at 50-70 C. with reducing agent to reduce the monomer residual ratio. The reducing agent is selected from sulfites such as alkali metal metasulfite, sulfite and hyposulfite, sodium formaldehyde sulfoxylate (SFS), t-butyl hydroperoxide (TBHP), and reducing sugars such as ascorbic acid and isoascorbic acid; wherein, sodium formaldehyde sulfoxylate (SFS) is eliminated after used on monomers such as methyl methacrylate and 2-hydroxyethyl acrylate; tert-butyl hydroperoxide (TBHP) is eliminated after used on monomers such as ethyl acrylate and butyl acrylate. The amount of the reducing agent is 0.1-0.3 wt % based on the total amount in weight of the acrylate monomer, and is 0.01-0.08 wt % based on the total amount in weight of the reactive material.

(32) 5. Resin Blending:

(33) To further enhance the physical properties of the acrylic graft modification water-based polyurethane, based on the total amount in weight of the water-based polyurethane, add waterborne bridging agent 3-9 wt % and cellulose nanofiber (CNF) 0.1-2 wt %, preferably add waterborne bridging agent 6 wt % and cellulose nanofiber 0.1 wt %, and most preferably add polycarbodiimide waterborne bridging agent 6 wt % and the cellulose nanofiber (CNF-1) 0.1 wt %, so as to prepare water-based polyurethane having high heat resistance and high scratch resistance.

(34) The waterborne bridging agent is selected from waterborne bridging agent of polycarbodiimide, aziridine type, oxazoline group, NCO type, melamine type and epoxy group, and can be used alone or in combination of two or more. Preferably, the polycarbodiimide waterborne bridging agent is selected.

(35) The cellulose nanofibers are selected from cellulose nanofiber having a fiber diameter of 3-10 nm and a fiber length of 100 nm-3 m, and may be used alone or in combination of two or more. Preferably, the cellulose nanofiber CNF-1 having a diameter of 5-10 nm and a fiber length of 1-3 m is used.

(36) More specifically, the water-based polyurethane synthesis method of the present disclosure uses an acrylic graft modification without using an acetone solvent, and the specific synthesis steps are as follows:

(37) 1. Preparation of Prepolymer:

(38) Based on the total amount in weight of reactive materials (including deionized water), 15-25 wt % of poly-polyol after vacuum dehydration is added to a reactor equipped with a stirrer, a thermometer and a condenser tube until the temperature of the oil bath reaches 70-80 C., and then 5-12 wt % of metered diisocyanate is added to cause a synthesis reaction. The polypolyol is selected from CD220 polycarbonate diol (molecular weight 2000), NY-2058 polyester diol (molecular weight 2000) and 1,6-hexanediol.

(39) 2. Dilution and Chain Extension of the Prepolymer:

(40) After the prepolymer is reacted for 2-3 hours, add 10-30 wt % acrylic monomer to dilute viscosity and maintain the temperature at 85-90 C. until the NCO content reaches the theoretical value (measured by di-n-butylamine method), then 1.5 to 3.0 wt % of the sulfonate chain extender is added, preferably sodium edetate ethyl sulfonate (AAS) is added, and the reaction is continued for 25-40 minutes;

(41) 3. Water Dispersion:

(42) The polymer obtained in step 2. is cooled to room temperature, and an appropriate amount of deionized water is added at 35-55 wt % under a high-speed shearing force of 500 rpm, and 0.1-0.5 wt % of a metered chain extender is added to carry out chain extension reaction for about 30 minutes, so as to prepare a solvent-free sulfonate-type water-based polyurethane.

(43) 4. Acrylic Synthesis:

(44) The sulfonate-type water-based polyurethane of the preceding step (3) is added with an emulsifier of 0.3-1.0 wt % to form an emulsion, and the temperature is raised to 50-70 C., and then 0.05-0.5 wt % of a initiator is added dropwise to carry out polymerization of the acrylate. Further, the temperature is raised to 75-85 C., and the temperature is maintained for 1-3 hours. Later the temperature is lowered to 50-70 C., and then the reducing agent is added 0.01-0.08 wt % to obtain acrylic graft modification water-based polyurethane.

(45) 5. Resin Blending:

(46) Based on the total amount in weight of the acrylic graft modification water-based polyurethane of the previous step 4., add polycarbodiimide waterborne bridging agent 3-9 wt % and cellulose nanofiber 0.1-2 wt % to the acrylic graft modification water-based polyurethane of the previous step 4. so as to obtain water-based polyurethane with high heat resistance and high scratch resistance.

(47) The solvent-free water-based polyurethane manufacturing method of the present disclosure using acrylic graft modification will be further described below with reference to the embodiment and the comparative examples, but the present disclosure is not limited thereto.

Embodiment 1

(48) Preparation of Water-Based Polyurethane (A Resin):

(49) 78.8 g CD220 (polycarbonate diol, molecular weight 2000), 20 g NY-2058 (polyester diol, molecular weight 2000), 6.44 g 1,6-HG (1,6-hexanediol, molecular weight 118) are sequentially added to the reactor, and temperature is raised to 80 C. under constant stirring. Then, 43.5 g of isophorone diisocyanate is added, and temperature is raised to 85-90 C., and reacted at this temperature for 2-3 hours. At this time, 131.2 g of methyl methacrylate (MMA), 9.6 g 2-hydroxyethyl acrylate (2-HEA), 9.6 g ethyl acrylate (EA), 4.8 g acrylic acid (AA), 2.4 g glycidyl methacrylate (GMA)), and 2.4 g triallyl isocyanurate (TAIC) are added sequentially so as to diluted and reduce viscosity. 10.7 g sodium ethylenediamine ethanesulfonate (AAS) is added to the prepolymer, and after the reaction continues for 25-40 minutes, the temperature is lowered to room temperature, then 236.3 g of deionized water is added at 500 rpm, and then 0.95 g of ethylenediamine is added. The chain extension reaction is carried out for about 30 minutes to prepare solvent-free sulfonate-type water-based polyurethane emulsion.

(50) Preparation of Polyacrylic Emulsion (B Resin):

(51) Under rapid stirring, 4.8 g of sodium lauryl sulfate (SLS) is added to the obtained sulfonate-type water-based polyurethane emulsion, and the temperature is raised to 50-70 C., followed by dropwise addition of aqueous ammonium persulfate solution (APS) 0.40 g. Continue to raise the temperature to 75-85 C., and maintain at this temperature for 1-3 hours. After cooling to 50-70 C., 0.15 g of reducing agent t-butyl hydroperoxide solution (TBHP) and 0.16 g sodium formaldehyde sulfoxylate (SFS) are added and reacted for 30 minutes to obtain acrylic graft modification water-based polyurethane.

(52) According to the weight ratio (wt %) of the (A resin):(B resin)=1:1, the film is formed by acrylic graft modification water-based polyurethane obtained by mixing A resin and B resin. The physical properties of the film are tested and the results are shown in Table 1.

Embodiment 2

(53) Preparation of Water-Based Polyurethane (A Resin):

(54) 157.6 g CD220 (polycarbonate diol, molecular weight 2000), 40 g NY-2058 (polyester diol, molecular weight 2000), 12.88 g 1,6-HG (1,6-hexanediol, molecular weight 118) are sequentially added to the reactor, and temperature is raised to 80 C. under constant stirring. Then, 87 g of isophorone diisocyanate is added, and temperature is raised to 85-90 C., and reacted at this temperature for 2-3 hours. At this time, 131.2 g methyl methacrylate (MMA), 9.6 g 2-hydroxyethyl acrylate (2-HEA), 9.6 g ethyl acrylate (EA), 4.8 g acrylic acid (AA), 2.4 g of glycidyl methacrylate (GMA)), and 2.4 g triallyl isocyanurate (TAIC) are added sequentially so as to diluted and reduce viscosity. 21.4 g sodium ethylenediamine ethanesulfonate (AAS) is added to the prepolymer, and after the reaction continues for 25-40 minutes, the temperature is lowered to room temperature, then 472.6 g of deionized water is added at 500 rpm, and then 1.9 g of ethylenediamine is added. The chain extension reaction is carried out for about 30 minutes to prepare solvent-free sulfonate-type water-based polyurethane emulsion.

(55) Preparation of Polyacrylic Emulsion (B Resin):

(56) Under rapid stirring, 4.8 g of sodium lauryl sulfate (SLS) is added to the obtained sulfonate-type water-based polyurethane emulsion, and the temperature is raised to 50-70 C., followed by dropwise addition of aqueous ammonium persulfate solution (APS) 0.40 g. Continue to raise the temperature to 75-85 C., and maintain at this temperature for 1-3 hours. After cooling to 50-70 C., 0.15 g of reducing agent t-butyl hydroperoxide solution (TBHP) and 0.16 g sodium formaldehyde sulfoxylate (SFS) are added and reacted for 30 minutes to obtain acrylic graft modification water-based polyurethane.

(57) The amount of the A resin is increased, and by the weight ratio (wt %) of the (A resin):(B resin)=2:1, the film is formed by acrylic graft modification water-based polyurethane obtained by mixing A resin and B resin. The physical properties of the film are tested and the results are shown in Table 1.

Embodiment 3

(58) Preparation of Water-Based Polyurethane (A Resin):

(59) 236.4 g CD220 (polycarbonate diol, molecular weight 2000), 60 g NY-2058 (polyester diol, molecular weight 2000), 19.32 g 1,6-HG (1,6-hexanediol, molecular weight 118) are sequentially added to the reactor, and temperature is raised to 80 C. under constant stirring. Then, 130.5 g of isophorone diisocyanate is added, and temperature is raised to 85-90 C., and reacted at this temperature for 2-3 hours. At this time, 131.2 g methyl methacrylate (MMA), 9.6 g 2-hydroxyethyl acrylate (2-HEA), 9.6 g ethyl acrylate (EA), 4.8 g acrylic acid (AA), 2.4 g of glycidyl methacrylate (GMA)), and 2.4 g triallyl isocyanurate (TAIC) are added sequentially so as to diluted and reduce viscosity. 32.1 g sodium ethylenediamine ethanesulfonate (AAS) is added to the prepolymer, and after the reaction continues for 25-40 minutes, the temperature is lowered to room temperature, then 708.9 g of deionized water is added at 500 rpm, and then 2.9 g of ethylenediamine is added. The chain extension reaction is carried out for about 30 minutes to prepare a solvent-free sulfonate-type water-based polyurethane emulsion.

(60) Preparation of Polyacrylic Emulsion (B Resin):

(61) Under rapid stirring, 4.8 g of sodium lauryl sulfate (SLS) is added to the obtained sulfonate-type water-based polyurethane emulsion, and the temperature is raised to 50-70 C., followed by dropwise addition of aqueous ammonium persulfate solution (APS) 0.40 g. Continue to raise the temperature to 75-85 C., and maintain at this temperature for 1-3 hours. After cooling to 50-70 C., 0.15 g of reducing agent t-butyl hydroperoxide solution (TBHP) and 0.16 g sodium formaldehyde sulfoxylate (SFS) are added and reacted for 30 minutes to obtain acrylic graft modification water-based polyurethane.

(62) The amount of the A resin is increased, and by the weight ratio (wt %) of the (A resin):(B resin)=3:1, the film is formed by acrylic graft modification water-based polyurethane obtained by mixing A resin and B resin. The physical properties of the film are tested and the results are shown in Table 1.

Comparative Example 1

(63) Preparation of Water-Based Polyurethane by Acetone: (A Resin):

(64) 59.82 g CD220 (polycarbonate diol, molecular weight 2000), 15.18 g NY-2058 (polyester diol, molecular weight 2000), 7.3 g 1,6-HG (1,6-hexanediol, molecular weight 118) are sequentially added to the reactor, and temperature is raised to 80 C. under constant stirring. Then, 58.8 g of isophorone diisocyanate is added, and temperature is raised to 85-90 C., and reacted at this temperature for 2-3 hours. After cooling temperature to 30-50 C., 160 g of acetone is added to reduce viscosity. After 20 minutes, add 17.5 g of sodium ethylenediamine sulfonate (AAS). The temperature is cooled to room temperature after the reaction is continued for 25-40 minutes, then 266.6 g of deionized water is added at 500 rpm, and 1.1 g of ethylenediamine is added for chain extension reaction for about 30 minutes. Later, acetone is distilled to obtain acyl-free water-based polyurethane emulsion which is free of acrylic.

(65) A film is formed by processing an acrylic-free sulfonate-based water-based polyurethane emulsion (A resin). The physical properties of the film were tested and the results are shown in Table 1.

(66) TABLE-US-00001 TABLE 1 Formulation composition and physical properties of the prepared film Comparative Embodiment 1 Embodiment 2 Embodiment 3 example 1 Test Result Tensile strength (kg/cm.sup.2) 420 358 296 231 Elongation at break (%) 355 407 470 520 Heat resistance 5.0 5.8 6.8 8.0 (120 C.*7 days)E Scratch resistance Scratches Scratches Scratches Scratches Heat resistant adhesive Slightly sticky non-sticky non-sticky severely sticky (80 C.*3 Kg*24 hr) Hydrolysis resistance Slightly cracked no cracks no cracks severely cracked (10% NaOH*8 hr) Acetone content (ppm) N/D N/D N/D 2530 ppm

(67) According to the physical property test results of Table 1, the film properties of embodiments 1-3 increased according to the ratio of acryl in water-based polyurethane. The tensile strength increased, the elongation at break decreased, the heat-resistant adhesive and hydrolysis resistance improved, and the heat resistance decline. This description, by means of acrylic graft modification, can compensate for the disadvantages of water-based polyurethane, such as low mechanical strength, poor heat resistance and hydrolysis resistance.

Embodiments 4-15 and Comparative Example 2

(68) The acrylic graft modification water-based polyurethane prepared from embodiment 1 is taken. According to the type and amount of waterborne bridging agent in Table 2, acrylic graft modification water-based polyurethane is added with waterborne bridging agent. The waterborne bridging agent is selected from carbodiimide, aziridine type, oxazoline group, NCO type, melamine type, or epoxy group, etc., and the addition amount is 3-9 wt %.

(69) The acrylic graft modification water-based polyurethane of the embodiments 4-15 was processed to form a film. The physical properties of the film are tested and the results are shown in Table 2.

(70) Comparative Example 2 is acrylic graft modification water-based polyurethane prepared from embodiment 1. The waterborne bridging agent is not added, and the physical properties of the film were tested after being processed to form a film. The results are shown in Table 2.

(71) TABLE-US-00002 TABLE 2 Formulation of film physical property test results prepared by waterborne bridging agent Types of bridging agent Heat Sample Aziridine Oxazoline NCO resistance Scratch number carbodiimide type group type E resistance embodiment 4 3 wt % 4.5 Slightly scratched embodiment 5 6 wt % 4.2 No scratches embodiment 6 9 wt % 4.3 No scratches embodiment 7 3 wt % 5.5 Slightly scratched embodiment 8 6 wt % 5.9 No scratches embodiment 9 9 wt % 6.1 No scratches embodiment 10 3 wt % 5.0 Slightly scratched embodiment 11 6 wt % 4.8 Slightly scratched embodiment 12 9 wt % 4.9 Slightly scratched embodiment 13 3 wt % 5.2 Slightly scratched embodiment 14 6 wt % 5.0 No scratches embodiment 15 9 wt % 5.0 No scratches Comparative 5.0 Scratches Example 2

(72) The acrylic emulsion contains COOH. The active hydrogen atom (H) or water-based polyurethane (containing active hydrogen atom H) can be added to the waterborne bridging agent reaction to improve adhesion, washing fastness, abrasion resistance, heat-resistant adhesion and other physical properties.

(73) According to the film physical properties test results of Table 2, that is, comparing the physical properties of the films of the embodiments 4-15 and the comparative example 2, that the formation of the film by the acrylic graft modification water-based polyurethane resin added with the waterborne bridging agent can enhance the acrylic graft modification water-based polyurethane heat resistance and scratch resistance is confirmed.

(74) According to the results of the film physical properties test of Table 2, the best scratch resistance was obtained by adding an acrylic graft modification water-based polyurethane resin 6 wt % of carbodiimide type waterborne bridging agent.

Embodiments 16-24 and Comparative Example 3

(75) The acrylic graft modification water-based polyurethane prepared from embodiment 1 is taken. According to the type and amount of cellulose nanofiber and waterborne bridging agent in Table 3, acrylic graft modification water-based polyurethane is added with cellulose nanofiber and waterborne bridging agent. The waterborne bridging agent is carbodiimide type waterborne bridging agent added in an amount of 6 wt %; the cellulose nanofiber (cellulose nanofiber; CNF) is selected from fiber having a diameter of 3-100 nm and a fiber length of 100 nm-5 m. The cellulose nanofiber is added in an amount of 0.1-2 wt %.

(76) The acrylic graft modification water-based polyurethane of the embodiments 16-24 was processed to form a film. The physical properties of the film are tested and the results are shown in Table 3.

(77) Comparative Example 3 is acrylic graft modification water-based polyurethane prepared from embodiment 1, and adding 6 wt % carbodiimide type waterborne bridging agent, but without adding cellulose nanofiber, after being processed to form a film, the test film is obtained. The physical properties are shown in Table 3.

(78) TABLE-US-00003 TABLE 3 Formulation of film physical property test results prepared by adding cellulose nanofiber Types of cellulose nanofiber specification CNF-1 CNF-3 CNF-4 bridging diameter agent 5~10 nm 5~10 nm 3~10 nm Carbodiimide length Heat Scratch Sample number (wt %) 1~3 m 100~500 nm 100~500 nm resistance E resistance embodiment16 6 0.1 wt % 3.5 No scratches embodiment17 6 0.5 wt % 3.5 No scratches embodiment18 6 1 wt % 3.8 Slightly scratched embodiment19 6 0.1 wt % 4.2 No scratches embodiment20 6 0.5 wt % 4.0 No scratches embodiment21 6 1 wt % 4.3 Slightly scratched embodiment22 6 0.1 wt % 4.3 No scratches embodiment23 6 0.5 wt % 4.0 No scratches embodiment24 6 1 wt % 4.0 Slightly scratched Comparative 6 4.2 No Example 3 scratches

(79) According to the results of the physical property test of the film of Table 3, that is, comparing the physical properties of the films of the embodiments 16-24 and the comparative example 3, that the film is formed by the addition of waterborne bridging agent and cellulosegraft modification water-based polyurethane resin is confirmed. In addition to improving scratch resistance, the mechanical strength, water resistance, heat resistance and film formability of the acrylic graft modification water-based polyurethane resin can be further improved.

(80) According to the results of the physical property test of the film of Table 3, the embodiments 16 and 17 can obtain the best heat resistance and scratch resistance by adding 0.5-0.5 wt % nanofiber CNF-1 (diameter 5-10 nm, fiber length 1-3 m) waterborne bridging agent acrylic graft modification water-based polyurethane resin.

(81) In conclusion, the water-based polyurethane of the present disclosure can enhance mechanical strength, and improve characteristics of water resistance, heat resistance, scratch resistance and film formation, etc., by means of acrylic graft modification and addition of waterborne bridging agent and cellulose Nano fiber. In particular, when a film is produced using the water-based polyurethane of the present disclosure, the film can be provided with good scratch resistance, heat resistance, heat-resistant adhesiveness, hydrolysis resistance, mechanical properties, and the like.

(82) The foregoing description of the exemplary embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

(83) The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to enable others skilled in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present disclosure pertains without departing from its spirit and scope.