Graphene modified polyurethane oligomer as well as preparation method and application thereof

Abstract

The invention relates to the field of photocureable coatings, in particular to a graphene modified polyurethane oligomer as well as a preparation method and application thereof. The graphene modified polyurethane oligomer is prepared from the following raw materials: polyether polyol, single-layer graphene oxide, polyisocyanate, a photocuring reaction monomer, a chain extender, a catalyst and a solvent, the carbon-oxygen ratio of the single-layer graphene oxide is less than or equal to 4; in the graphene modified polyurethane oligomer, graphene is interspersed in a polyurethane network and is connected with polyurethane through covalent bonds and non-covalent bonds. The prepared graphene modified polyurethane oligomer can further improve the wear resistance and ultraviolet resistance of the coating, and the coating is excellent in adhesive force and hardness and high in curing efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photocuring coatings, more particularly, it relates to a graphene modified polyurethane oligomer and a preparation method and application thereof. BACKGROUND

[0002] Photocuring paint is widely used in the field of indoor building materials due to its fast curing rate, good surface performance, controllable surface gloss and other advantages. However, due to the presence of a large amount of photosensitive resin in the formula of photocuring paint, the resin itself often has poor ultraviolet resistance, and the wear resistance is also not ideal. Therefore, photocuring paint has been difficult to be applied to outdoor scenes with higher requirements.

[0003] Graphene is a new type of two-dimensional carbon nanomaterial, which has excellent optical, electrical and mechanical properties, and also has good biological inhibition and chemical stability. In recent years, as a multifunctional material, it has been widely used in various fields of new composite materials. Graphene material can effectively improve the mechanical properties of the matrix material, and also effectively block and absorb ultraviolet light, improving the ultraviolet resistance of the matrix material.

[0004] However, although graphene itself has excellent multifunctionality, its complex preparation process, high cost, and poor dispersibility and reactivity make it unsuitable for direct use as a functional additive in photocuring coating systems. SUMMARY

[0005] The present application provides a graphene modified polyurethane oligomer and a preparation method and application thereof. The present application not only facilitates the uniform introduction of graphene into the coating system, but more importantly, the graphene modified polyurethane oligomer prepared by the present application can further improve the wear resistance and ultraviolet resistance of the coating, and the coating has excellent adhesion, hardness and high curing efficiency.

[0006] In a first aspect, the present application provides a graphene modified polyurethane oligomer, which adopts the following technical solution:

[0007] A graphene modified polyurethane oligomer is made from raw materials including polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring reaction monomer, chain extender, catalyst and solvent; the carbon-oxygen ratio of the single-layer graphene oxide is ≤4; in the graphene modified polyurethane oligomer, graphene is interpenetrated in the polyurethane network and connected to the polyurethane through covalent bonds and non-covalent bonds.

[0008] By adopting the technical scheme, the graphene oxide is used as the reaction raw material, the cost and the manufacturing difficulty of which are lower than those of the graphene, and the graphene oxide has more reaction groups such as hydroxyl groups and carboxyl groups on the surface, which can effectively react with the polyurethane raw material to obtain the graphene modified polyurethane oligomer. In addition, the single-layer graphene oxide with a carbon-oxygen ratio of less than or equal to 4 is selected, the graphene oxide has a proper number of active functional groups by controlling the carbon-oxygen ratio, has good reactivity and dispersibility, can fully react with other reaction monomers, improves the strength and wear resistance of the matrix, and does not cause black precipitates in the UV coating, which seriously affects the appearance and performance of the coating. Moreover, in the graphene modified polyurethane oligomer, the graphene is inserted into the polyurethane network, which can effectively improve the dispersibility of the graphene, avoid the graphene from being too much on the surface of the polyurethane, and affect the dispersibility of the graphene in the coating system. In addition, in the polyurethane network, the graphene is connected to the polyurethane through hydrogen bonds, non-covalent bonds, ester bonds or ether bonds and covalent bonds. Such a structure further improves the dispersibility and reduces the problem of defects in the crosslinked network of the polyurethane caused by the agglomeration of the graphene, which is beneficial to improving the overall performance of the product.

[0009] In summary, the graphene component can be successfully introduced into the coating, the dispersibility of the graphene in the UV coating is effectively improved, the anti-ultraviolet performance and wear resistance of the coating are improved, and the curing process and film forming process of the UV varnish are not affected.

[0010] Further, the weight ratio of the polyether polyol, the single-layer graphene oxide, the polyisocyanate, the photocuring reaction monomer, the chain extender, the catalyst and the solvent is (20-30) : (1-2) : (10-15) : (5-10) : (60-80) : (0.5-1) : (120-150).

[0011] Further, the polyether polyol includes at least one of pentaerythritol-epoxy propane polyether tetraol and pentaerythritol-epoxy ethane polyether tetraol. Further, the molecular weight of the polyether polyol is 600-1000. Further, the carbon-oxygen ratio of the single-layer graphene oxide is 3-4.

[0012] By adopting the above technical scheme, in the use of the polyether polyol, the pentaerythritol-epoxy propane polyether tetraol and the pentaerythritol-epoxy ethane polyether tetraol have multiple reaction groups, which can effectively improve the reaction conversion rate with the graphene oxide, improve the wear resistance and hardness of the coating matrix; the polyether polyol with a molecular weight of 600-1000 helps the mutual dispersion of the polyether polyol and the graphene oxide, the polyether polyol is more easily penetrated into the interlayer structure of the graphene oxide, the reaction efficiency is improved, and the obtained polymer network is more stable; in addition, the use of a polyether polyol with a higher molecular weight is avoided, and the problem of a decrease in the hardness of the coating is reduced. The graphene oxide has a proper number of active functional groups and has good reactivity, so that it and other reaction monomers are fully reacted, and the strength and wear resistance of the coating are further improved.

[0013] Further, the photocuring reaction monomer includes at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, and dipropylene glycol diacrylate.

[0014] Further, the chain extender includes at least one of 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid, or 2,3-dihydroxy succinic acid.

[0015] By adopting the above technical scheme, in the reaction system of the present application, the chain extender not only plays a basic chain extension role, but also provides a polar group for the graphene oxide, thereby improving the dispersion effect of the graphene in the system.

[0016] Further, the catalyst includes at least one of dibutyl tin dilaurate, dibutyl tin diacetate, and tin dimethyl dithioformate.

[0017] Further, the solvent includes at least one of ethyl acetate and isoamyl butyrate.

[0018] Further, the polyisocyanate includes at least one of HDI trimer, IPDI, and H12MDI.

[0019] In a second aspect, the present application provides a preparation method of a graphene modified polyurethane oligomer, which adopts the following technical scheme:

[0020] A preparation method of a graphene modified polyurethane oligomer includes the following steps:

[0021] The polyether polyol, single-layer graphene oxide and chain extender are stirred uniformly at a temperature of 40-45℃; the polyisocyanate is added, the temperature is raised to 55-60℃, and stirring is performed for 5-10 min; the catalyst is further added, the temperature is raised to 75-80℃, and stirring is performed for 2.5-3 h; the temperature is lowered to 55-60℃, the photocuring monomer is added dropwise, and stirring is continued for 3-5 h, then the temperature is lowered to 40-45℃, the solvent is added, and stirring is performed for 0.5-1 h, thereby obtaining the graphene-modified polyurethane oligomer.

[0022] By adopting the technical solution, the single-layer graphene oxide is pre-reacted with the polyether polyol and the chain extender, the polarity and viscosity of the reaction system are favorable for the dispersion of the graphene oxide, the graphene oxide can form hydrogen bonds with the polyether polyol and the chain extender, and the flexible chain segment of the polyether polyol can wrap the graphene oxide; in the subsequent reaction process, the graphene oxide can be in-situ reacted, the dispersion of the graphene oxide is improved, the reaction stability is improved, and the graphene is interpenetrated in the polyurethane network, thereby obtaining an oligomer with excellent performance.

[0023] In a third aspect, the graphene-modified polyurethane oligomer is applied in UV coatings.

[0024] In summary, the graphene-modified polyurethane oligomer has the following advantages:

[0025] The graphene-modified polyurethane oligomer prepared by the method has good dispersibility when added to the coating, does not cause black precipitates in the UV coating, and does not affect the appearance of the coating. Moreover, the graphene-modified polyurethane oligomer does not affect the film formation and curing of the coating, improves the overall ultraviolet resistance of the coating, and effectively improves the wear resistance after curing and film formation, and is very suitable for use on the surface of outdoor building materials. DETAILED DESCRIPTION

[0026] The application is further described below in combination with examples.

[0027] Example

[0028] The specific embodiment of the application first provides a graphene-modified polyurethane oligomer, and the raw materials include polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring monomer, chain extender, catalyst and solvent in a weight ratio of (20-30):(1-2):(10-15):(5-10):(60-80):(0.5-1):(120-150).

[0029] In the above raw materials, the polyether polyol includes at least one of pentaerythritol-epoxypropane polyether tetraol and pentaerythritol-epoxyethane polyether tetraol, and the molecular weight of the polyether polyol is 600-1000.

[0030] The carbon-oxygen ratio of the single-layer graphene oxide is 3-4, wherein the carbon-oxygen ratio is the ratio of the element content (atomic fraction). The polyisocyanate includes at least one of HDI trimer, IPDI, and H12MDI. The photocuring reaction monomer includes at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, and dipropylene glycol diacrylate. The chain extender includes at least one of 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid, or 2,3-dihydroxy succinic acid. The catalyst includes at least one of dibutyl tin dilaurate, dibutyl tin diacetate, and tin dimethyl dithioformate. The solvent includes at least one of ethyl acetate and isoamyl butyrate.

[0031] The specific embodiment of the present application further provides a preparation method of the graphene modified polyurethane oligomer, including the following steps:

[0032] The polyether polyol, the single-layer graphene oxide, and the chain extender are stirred uniformly at a temperature of 40-45°C; the polyisocyanate is added, the temperature is raised to 55-60°C, and stirring is performed for 5-10 min; the catalyst is further added, the temperature is raised to 75-80°C, and stirring is performed for 2.5-3 h; the temperature is lowered to 55-60°C, the photocuring reaction monomer is added dropwise, and stirring is continuously performed for 3-5 h; then the temperature is lowered to 40-45°C, the solvent is added, and stirring is performed for 0.5-1 h, thereby obtaining the graphene modified polyurethane oligomer.

[0033] Specifically, the polyether polyol, the single-layer graphene oxide, and the chain extender are stirred uniformly at a temperature of 40-45°C, and the stirring speed is 300-500 rpm (preferably 400 rpm); the polyisocyanate is added, the temperature is raised to 55-60°C, and stirring is performed for 5-10 min, and the stirring speed is 500-700 rpm (preferably 600 rpm); the catalyst is further added, the temperature is raised to 75-80°C, and stirring is performed for 2.5-3 h, and the stirring speed is 200-400 rpm (preferably 300 rpm); the temperature is lowered to 55-60°C, the photocuring reaction monomer is added dropwise, the dropping speed is 1-2 ml / min (preferably 1.5 ml / min), and stirring is continuously performed for 3-5 h, and the stirring speed is 400-600 rpm (preferably 500 rpm); then the temperature is lowered to 40-45°C, the solvent is added, and stirring is performed for 0.5-1 h, and the stirring speed is 600-800 rpm (preferably 700 rpm), thereby obtaining the graphene modified polyurethane oligomer.

[0034] For the application of the graphene modified polyurethane oligomer prepared above, the specific embodiment of the present application further provides a strong ultraviolet resistant high abrasion resistance UV coating, and the raw materials thereof include UV light oil, light stabilizer, dispersant, and graphene modified polyurethane oligomer in a weight ratio of (80-120):(0.5-2):(1-3):(8-15).

[0035] UV varnish is a conventional varnish, which can be ZU52301 of Zhenzhen, CAF-6021 of Junzilan, and J112-3 of Hengxing. ZU52301 of Zhenzhen is used in the specific embodiment of the present application.

[0036] The light stabilizer is Tinuvin 900, Tinuvin 400, and Tinuvin 292 of Ciba. The dispersant is prepared by mixing 10%-15wt% fumed silica or titanium dioxide in ethyl acetate or isoamyl butyrate.

[0037] The preparation method of the above-mentioned UV coating with high resistance to strong ultraviolet and high wear resistance comprises the following steps: adding the UV varnish and the light stabilizer into a reaction kettle, mixing them uniformly at a temperature of 30-35°C and a rotation speed of 850-1000r / min; then adding the dispersant into the reaction kettle, mixing for 5-10min at the same rotation speed; then adding the graphene modified polyurethane oligomer into the reaction kettle, increasing the rotation speed to 1400-1600r / min, and mixing for 0.5-1h; finally increasing the temperature of the reaction kettle to 90-120°C, keeping a slight negative pressure in the kettle, and mixing for 1-2h at the same rotation speed, to obtain the finished product of the UV coating.

[0038] The following is explained and described through specific examples.

[0039] Example 1

[0040] The present embodiment first provides a graphene modified polyurethane oligomer, and the raw materials thereof include polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring reaction monomer, chain extender, catalyst, and solvent, with a weight ratio of 26:1.5:13:6:60:0.5:120.

[0041] In the above-mentioned raw materials, the polyether polyol is pentaerythritol-epoxy propane polyether tetraol with a molecular weight of 800. The carbon-oxygen ratio of the single-layer graphene oxide is 3.5. The polyisocyanate is HDI trimer. The photocuring reaction monomer is hydroxyethyl methacrylate. The chain extender is 2,2-dimethylol propionic acid (DMPA). The catalyst is dibutyl tin dilaurate. The solvent is ethyl acetate.

[0042] The present embodiment also provides a preparation method of the graphene modified polyurethane oligomer, which comprises the following steps:

[0043] The polyether polyol, the single-layer graphene oxide, and the chain extender are stirred uniformly at a temperature of 45°C. The polyisocyanate is added, the temperature is increased to 58°C, and the stirring is performed for 8min. The catalyst is added, the temperature is increased to 78°C, and the stirring is performed for 2.8h. The temperature is decreased to 56°C, the photocuring reaction monomer is added dropwise, the stirring is continued for 4h, then the temperature is decreased to 43°C, the solvent is added, and the stirring is performed for 0.6h, to obtain the graphene modified polyurethane oligomer.

[0044] Example 2

[0045] The embodiment first provides a graphene modified polyurethane oligomer, raw materials of which include polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring reaction monomer, chain extender, catalyst and solvent in a weight ratio of 20:1:15:5:78:0.8:130.

[0046] In the above raw materials, the polyether polyol is pentaerythritol-epoxy propane polyether tetraol with a molecular weight of 600. The carbon-oxygen ratio of the single-layer graphene oxide is 4. The polyisocyanate is IPDI, and the photocuring reaction monomer is hydroxyethyl methacrylate. The chain extender is 2,2-dimethylol propionic acid (DMPA). The catalyst is dibutyl tin dilaurate. The solvent is isoamyl butyrate.

[0047] The embodiment further provides a preparation method of the graphene modified polyurethane oligomer, including the following steps:

[0048] The polyether polyol, single-layer graphene oxide and chain extender are stirred uniformly at a temperature of 40°C; the polyisocyanate is added, the temperature is raised to 60°C, and stirring is performed for 5 min; the catalyst is further added, the temperature is raised to 75°C, and stirring reaction is performed for 3 h; the temperature is lowered to 55°C, the photocuring reaction monomer is added dropwise, stirring is continuously performed for 5 h, then the temperature is lowered to 40°C, the solvent is added, and stirring is performed for 0.5 h, thereby obtaining the graphene modified polyurethane oligomer.

[0049] Example 3

[0050] The embodiment first provides a graphene modified polyurethane oligomer, raw materials of which include polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring reaction monomer, chain extender, catalyst and solvent in a weight ratio of 30:2:10:10:80:1:150.

[0051] In the above raw materials, the polyether polyol is pentaerythritol-epoxy propane polyether tetraol with a molecular weight of 600. The carbon-oxygen ratio of the single-layer graphene oxide is 4. The polyisocyanate is IPDI, and the photocuring reaction monomer is hydroxyethyl methacrylate. The chain extender is 2,2-dimethylol propionic acid (DMPA). The catalyst is dibutyl tin dilaurate. The solvent is isoamyl butyrate.

[0052] The embodiment further provides a preparation method of the graphene modified polyurethane oligomer, including the following steps:

[0053] The polyether polyol, single-layer graphene oxide and chain extender are stirred uniformly at a temperature of 43℃; the polyisocyanate is added, the temperature is raised to 56℃, and stirring is performed for 10 min; the catalyst is further added, the temperature is raised to 75℃, and stirring is performed for 2.5 h; the temperature is lowered to 55℃, the photocuring reaction monomer is added dropwise, stirring is continued for 5 h, then the temperature is lowered to 45℃, the solvent is added, and stirring is performed for 1 h, thereby obtaining the graphene-modified polyurethane oligomer.

[0054] Example 4

[0055] The example first provides a graphene-modified polyurethane oligomer, raw materials of which include polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring reaction monomer, chain extender, catalyst and solvent in a weight ratio of 28:1.3:14:8:77:0.7:130.

[0056] In the above raw materials, the polyether polyol is pentaerythritol-epoxy propane polyether tetraol with a molecular weight of 1000. The carbon-oxygen ratio of the single-layer graphene oxide is 4. The polyisocyanate is HDI trimer, and the photocuring reaction monomer is dipropylene glycol diacrylate. The chain extender is 2,2-dimethylol propionic acid (DMPA). The catalyst is dimethyl tin dimercaptouscinate. The solvent is isoamyl butyrate.

[0057] The example also provides a preparation method of a graphene-modified polyurethane oligomer, which includes the following steps:

[0058] The polyether polyol, single-layer graphene oxide and chain extender are stirred uniformly at a temperature of 42℃; the polyisocyanate is added, the temperature is raised to 59℃, and stirring is performed for 10 min; the catalyst is further added, the temperature is raised to 76℃, and stirring is performed for 2.6 h; the temperature is lowered to 57℃, the photocuring reaction monomer is added dropwise, stirring is continued for 3.5 h, then the temperature is lowered to 42℃, the solvent is added, and stirring is performed for 0.8 h, thereby obtaining the graphene-modified polyurethane oligomer.

[0059] Application Example

[0060] Application Example 1

[0061] The application example provides a strong ultraviolet-resistant high-wear-resistance UV coating, raw materials of which include UV gloss oil, light stabilizer, dispersant and graphene-modified polyurethane oligomer in a weight ratio of 100:2:3:10. The graphene-modified polyurethane oligomer is from Example 1. The light stabilizer is Tinuvin 900. The dispersant is formed by mixing 12% fumed silica in ethyl acetate as a solvent.

[0062] The preparation method of the strong ultraviolet resistant high wear-resistant UV coating comprises the following steps: adding UV light oil and light stabilizer into a reaction kettle, uniformly mixing at a temperature of 33 DEG C and a rotation speed of 900 r / min; then adding a dispersing agent, keeping the rotation speed unchanged, and mixing for 6 min; then adding a graphene modified polyurethane oligomer, increasing the rotation speed to 1500 r / min, and mixing for 0.8 h; finally, increasing the temperature of the reaction kettle to 100 DEG C, keeping micro-negative pressure in the kettle, keeping the rotation speed unchanged, and mixing for 1.5 h, to obtain the finished product UV coating.

[0063] Application Example 2

[0064] The strong ultraviolet resistant high wear-resistant UV coating provided in the application example comprises UV light oil, light stabilizer, dispersing agent and graphene modified polyurethane oligomer in a weight ratio of 120:0.5:1:15. The graphene modified polyurethane oligomer is from the embodiment 2. The light stabilizer is Tinuvin400. The dispersing agent is prepared by mixing 10% fumed titanium dioxide with isoamyl butyrate as a solvent.

[0065] The preparation method of the strong ultraviolet resistant high wear-resistant UV coating comprises the following steps: adding UV light oil and light stabilizer into a reaction kettle, uniformly mixing at a temperature of 30 DEG C and a rotation speed of 1000 r / min; then adding a dispersing agent, keeping the rotation speed unchanged, and mixing for 5 min; then adding a graphene modified polyurethane oligomer, increasing the rotation speed to 1600 r / min, and mixing for 1 h; finally, increasing the temperature of the reaction kettle to 90 DEG C, keeping micro-negative pressure in the kettle, keeping the rotation speed unchanged, and mixing for 1 h, to obtain the finished product UV coating.

[0066] Application Example 3

[0067] The strong ultraviolet resistant high wear-resistant UV coating provided in the application example comprises UV light oil, light stabilizer, dispersing agent and graphene modified polyurethane oligomer in a weight ratio of 80:1:1:8. The graphene modified polyurethane oligomer is from the embodiment 3. The light stabilizer is Tinuvin292. The dispersing agent is prepared by mixing 13% fumed silicon dioxide with ethyl acetate as a solvent.

[0068] The preparation method of the strong ultraviolet resistant high wear-resistant UV coating comprises the following steps: adding UV light oil and light stabilizer into a reaction kettle, uniformly mixing at a temperature of 30 DEG C and a rotation speed of 850 r / min; then adding a dispersing agent, keeping the rotation speed unchanged, and mixing for 10 min; then adding a graphene modified polyurethane oligomer, increasing the rotation speed to 1450 r / min, and mixing for 1 h; finally, increasing the temperature of the reaction kettle to 120 DEG C, keeping micro-negative pressure in the kettle, keeping the rotation speed unchanged, and mixing for 1 h, to obtain the finished product UV coating.

[0069] Application Example 4

[0070] The application example provides a strong ultraviolet resistant high wear-resistant UV coating, and raw materials of the strong ultraviolet resistant high wear-resistant UV coating include UV light oil, light stabilizer, dispersant and graphene modified polyurethane oligomer in a weight ratio of 110:1.6:1.8:13. The graphene modified polyurethane oligomer is from the example 4. The light stabilizer is Tinuvin 292. The dispersant is formed by mixing 12% fumed titanium dioxide with isoamyl butyrate as a solvent.

[0071] The preparation method of the strong ultraviolet resistant high wear-resistant UV coating comprises the following steps: the UV light oil and the light stabilizer are added into a reaction kettle, the temperature is 32 DEG C, and the uniform mixing is carried out at a rotating speed of 950 r / min; then the dispersant is added, the rotating speed is unchanged, and the mixing is carried out for 8 min; then the graphene modified polyurethane oligomer is added, the rotating speed is increased to 1600 r / min, and the mixing is carried out for 0.9 h; finally, the temperature of the reaction kettle is increased to 110 DEG C, the micro negative pressure is kept in the kettle, the rotating speed is unchanged, and the mixing is carried out for 1 h, so that the finished product UV coating is obtained.

[0072] Comparative example

[0073] Comparative example 1

[0074] A preparation method of a graphene modified polyurethane oligomer and a preparation method of a coating, comprising the following steps:

[0075] Step one: 1% single-layer graphene oxide dispersion (carbon oxygen ratio 3.5) is added into ethyl acetate, and stirring is carried out for 0.6 h, so that the single-layer graphene oxide dispersion is obtained.

[0076] Step two: 100 parts of UV light oil and 1 part of light stabilizer Tinuvin 90 are added into a reaction kettle, the temperature is 33 DEG C, and the uniform mixing is carried out at a rotating speed of 900 r / min.

[0077] Step three: 2 parts of dispersant are added, the rotating speed is unchanged, and the mixing is carried out for 6 min. The dispersant is formed by mixing 12% fumed silicon dioxide with ethyl acetate as a solvent.

[0078] Step four: 10 parts of the single-layer graphene oxide dispersion obtained in step one is added, the rotating speed is increased to 1500 r / min, and the mixing is carried out for 0.8 h.

[0079] Step five: the temperature of the reaction kettle is increased to 100 DEG C, the micro negative pressure is kept in the kettle, the rotating speed is unchanged, and the mixing is carried out for 1.5 h, so that the finished product UV coating is obtained.

[0080] Comparative example 2

[0081] A preparation method of a graphene modified polyurethane oligomer and a preparation method of a coating, comprising the following steps:

[0082] Step one: 26 parts of pentaerythritol-epoxy propane polyether tetrahydric alcohol (molecular weight 800), 1.5 parts of single-layer graphene oxide (carbon oxygen ratio 3.5), 66 parts of DMPA, and stirring uniformly at a temperature of 45℃;

[0083] Step two: 13 parts of polyisocyanate HDI trimer are added, the temperature is raised to 58℃, and stirring is carried out for 8 min;

[0084] Step three: 0.6 parts of dibutyl tin dilaurate are added, the temperature is raised to 78℃, and stirring is carried out for 2.8 h;

[0085] Step four: the temperature is lowered to 56℃, 6 parts of hydroxyethyl methacrylate are added dropwise, and stirring is continued for 4 h;

[0086] Step five: the temperature is lowered to 43℃, then 120 parts of ethyl acetate are added, and stirring is carried out for 0.6 h, thereby obtaining graphene modified polyurethane oligomers.

[0087] Step six: 100 parts of UV light oil and 1 part of light stabilizer Tinuvin 900 are added to the reaction kettle, the temperature is 33℃, and stirring is carried out uniformly at a speed of 900 r / min.

[0088] Step seven: 2 parts of dispersant are added thereto, the stirring speed is unchanged, and mixing is carried out for 6 min. The dispersant is 12% fumed silica mixed in ethyl acetate as solvent.

[0089] Step eight: 20 parts of graphene modified polyurethane oligomers obtained in step five are added thereto, the stirring speed is raised to 1500 r / min, and mixing is carried out for 0.8 h.

[0090] Step nine: the temperature of the reaction kettle is raised to 100℃, the kettle is kept at a slight negative pressure, the stirring speed is unchanged, and mixing is carried out for 1.5 h, thereby obtaining the finished product UV coating.

[0091] Comparative example 3

[0092] A preparation method of graphene modified polyurethane oligomers and a preparation method of coating, comprising the following steps:

[0093] Step one: 26 parts of pentaerythritol-epoxy propane polyether tetrahydric alcohol (molecular weight 800), 1.5 parts of graphene oxide, 66 parts of DMPA, and stirring uniformly at a temperature of 45℃;

[0094] Step two: 13 parts of polyisocyanate HDI trimer are added, the temperature is raised to 58℃, and stirring is carried out for 8 min;

[0095] Step three: 0.6 parts of dibutyl tin dilaurate are added, the temperature is raised to 78℃, and stirring is carried out for 2.8 h;

[0096] Step four: the temperature is reduced to 56℃, 6 parts of hydroxyethyl methacrylate are added dropwise, and stirring is continued for 4h;

[0097] Step five: the temperature is reduced to 43℃, then 120 parts of ethyl acetate are added, and stirring is continued for 0.6h to obtain the graphite modified polyurethane active functional oligomer.

[0098] Step six: 100 parts of UV light oil and 1 part of light stabilizer Tinuvin 900 are added to the reaction kettle, the temperature is 33℃, and uniform mixing is carried out at a speed of 900r / min.

[0099] Step seven: 2 parts of dispersant are added thereto, the speed is unchanged, and mixing is carried out for 6min. The dispersant is 12% fumed silica mixed in ethyl acetate as solvent.

[0100] Step eight: 10 parts of the graphite modified polyurethane active functional oligomer obtained in step five are added thereto, the speed is increased to 1500r / min, and mixing is carried out for 0.8h.

[0101] Step nine: the temperature of the reaction kettle is increased to 100℃, the kettle is kept under a slight negative pressure, the speed is unchanged, and mixing is carried out for 1.5h to obtain the finished product UV coating.

[0102] Comparative example 4

[0103] A preparation method of a graphene modified polyurethane oligomer and a preparation method of a coating, comprising the following steps:

[0104] Step one: 26 parts of pentaerythritol-epoxy propane polyether tetraol (molecular weight 800), 1.5 parts of single-layer graphene oxide (carbon oxygen ratio 5.5), and 66 parts of DMPA are uniformly stirred at a temperature of 45℃;

[0105] Step two: 13 parts of polyisocyanate HDI trimer are added, the temperature is increased to 58℃, and stirring is carried out for 8min;

[0106] Step three: 0.6 parts of dibutyl tin dilaurate are added, the temperature is increased to 78℃, and stirring reaction is carried out for 2.8h;

[0107] Step four: the temperature is reduced to 56℃, 6 parts of hydroxyethyl methacrylate are added dropwise, and stirring is continued for 4h;

[0108] Step five: the temperature is reduced to 43℃, then 120 parts of ethyl acetate are added, and stirring is continued for 0.6h to obtain the graphite modified polyurethane active functional oligomer.

[0109] Step six: 100 parts of UV light oil and 1 part of light stabilizer Tinuvin 900 are added to the reaction kettle, the temperature is 33℃, and uniform mixing is carried out at a speed of 900r / min.

[0110] Step seven: 2 parts of dispersant were added thereto, the rotation speed was not changed, and mixing was performed for 6 min. The dispersant was prepared by mixing 12% fumed silica in ethyl acetate as a solvent.

[0111] Step eight: 10 parts of the graphene-modified polyurethane oligomer obtained in step five were added thereto, the rotation speed was increased to 1500 r / min, and mixing was performed for 0.8 h.

[0112] Step nine: the temperature of the reaction kettle was increased to 100°C, a slight negative pressure was maintained in the kettle, the rotation speed was not changed, and mixing was performed for 1.5 h, and finally the finished product UV coating was obtained.

[0113] Comparative Example 5

[0114] A preparation method of a graphene-modified polyurethane oligomer and a preparation method of a coating, comprising the following steps:

[0115] Step one: 26 parts of pentaerythritol-epoxy propane polyether tetraol (molecular weight 800), 1.5 parts of single-layer graphene oxide (carbon oxygen ratio 2), and 66 parts of DMPA were uniformly stirred at a temperature of 45°C;

[0116] Step two: 13 parts of polyisocyanate HDI trimer were added, the temperature was increased to 58°C, and stirring was performed for 8 min;

[0117] Step three: 0.6 parts of dibutyltin dilaurate was added, the temperature was increased to 78°C, and stirring was performed for 2.8 h;

[0118] Step four: the temperature was decreased to 56°C, 6 parts of hydroxyethyl methacrylate were added dropwise, and stirring was continued for 4 h;

[0119] Step five: the temperature was decreased to 43°C, then 120 parts of ethyl acetate were added, and stirring was performed for 0.6 h, and graphene-modified polyurethane oligomer was obtained.

[0120] Step six: 100 parts of UV oil and 1 part of light stabilizer Tinuvin 900 were added to the reaction kettle, the temperature was 33°C, and uniform mixing was performed at a rotation speed of 900 r / min.

[0121] Step seven: 2 parts of dispersant were added thereto, the rotation speed was not changed, and mixing was performed for 6 min. The dispersant was prepared by mixing 12% fumed silica in ethyl acetate as a solvent.

[0122] Step eight: 10 parts of the graphene-modified polyurethane oligomer obtained in step five were added thereto, the rotation speed was increased to 1500 r / min, and mixing was performed for 0.8 h.

[0123] Step nine: the temperature of the reaction kettle was increased to 100°C, a slight negative pressure was maintained in the kettle, the rotation speed was not changed, and mixing was performed for 1.5 h, and finally the finished product UV coating was obtained.

[0124] Comparative Example 6

[0125] A preparation method of a graphene modified polyurethane oligomer and a preparation method of a coating, comprising the following steps:

[0126] Step one: 26 parts of pentaerythritol-epoxy propane polyether tetraol (molecular weight 3000), 1.5 parts of single-layer graphene oxide (carbon oxygen ratio 3.5), 66 parts of DMPA, are stirred uniformly at a temperature of 45°C;

[0127] Step two: 13 parts of polyisocyanate HDI trimer are added, the temperature is raised to 58°C, and stirring is performed for 8 min;

[0128] Step three: 0.6 parts of dibutyltin dilaurate are added, the temperature is raised to 78°C, and stirring is performed for 2.8 h;

[0129] Step four: the temperature is lowered to 56°C, 6 parts of hydroxyethyl methacrylate are added dropwise, and stirring is continued for 4 h;

[0130] Step five: the temperature is lowered to 43°C, then 120 parts of ethyl acetate are added, and stirring is performed for 0.6 h, thereby obtaining a graphene modified polyurethane oligomer.

[0131] Step six: 100 parts of UV light oil and 1 part of light stabilizer Tinuvin 900 are added to the reaction kettle, the temperature is 33°C, and uniform mixing is performed at a speed of 900 r / min.

[0132] Step seven: 2 parts of a dispersant are added thereto, the speed is not changed, and mixing is performed for 6 min. The dispersant is formed by mixing 12% fumed silica in ethyl acetate as a solvent.

[0133] Step eight: 10 parts of the graphene modified polyurethane oligomer obtained in step five are added thereto, the speed is raised to 1500 r / min, and mixing is performed for 0.8 h.

[0134] Step nine: the temperature of the reaction kettle is raised to 100°C, a slight negative pressure is maintained in the kettle, the speed is not changed, and mixing is performed for 1.5 h, thereby finally obtaining a finished product UV coating.

[0135] Comparative example 7

[0136] A preparation method of a graphene modified polyurethane oligomer and a preparation method of a coating, comprising the following steps:

[0137] Step one: 26 parts of pentaerythritol-epoxy propane polyether tetraol (molecular weight 3000), 1.5 parts of single-layer graphene oxide (carbon oxygen ratio 3.5), 66 parts of DMPA, are stirred uniformly at a temperature of 45°C;

[0138] Step two: 13 parts of polyisocyanate HDI trimer are added, the temperature is raised to 58°C, and stirring is performed for 8 min;

[0139] Step three: add 0.6 parts of dibutyl tin dilaurate, the temperature is raised to 78℃, and the reaction is stirred for 2.8h;

[0140] Step four: the temperature is lowered to 56℃, and 6 parts of hydroxyethyl methacrylate is added dropwise, and the stirring is continued for 4h;

[0141] Step five: the temperature is lowered to 43℃, and then 120 parts of ethyl acetate or isoamyl butyrate is added, and the stirring is continued for 0.6h to obtain the graphene modified polyurethane oligomer.

[0142] Step six: 100 parts of UV varnish and 1 part of light stabilizer Tinuvin 900 are added to the reaction kettle, the temperature is 33℃, and the mixing is uniform at a speed of 900r / min.

[0143] Step seven: 2 parts of dispersant is added thereto, the speed is unchanged, and the mixing is continued for 6min. The dispersant is 12% fumed silica mixed in ethyl acetate as the solvent.

[0144] Step eight: 10 parts of graphene modified polyurethane oligomer obtained in step five is added thereto, the speed is raised to 1500r / min, and the mixing is continued for 0.8h.

[0145] Step nine: the temperature of the reaction kettle is raised to 100℃, the kettle is kept under a slight negative pressure, the speed is unchanged, and the mixing is continued for 1.5h to obtain the finished product UV coating.

[0146] Comparative example 8

[0147] A graphene modified polyurethane oligomer, the raw materials of which include polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring reaction monomer, chain extender, catalyst and solvent in a weight ratio of 26:1.5:13:6:60:0.5:120.

[0148] In the above raw materials, the polyether polyol is pentaerythritol-epoxy propane polyether tetraol with a molecular weight of 800. The carbon oxygen ratio of the single-layer graphene oxide is 3.5. The polyisocyanate is HDI trimer. The photocuring reaction monomer is hydroxyethyl methacrylate. The chain extender includes 2,2-dimethylol propionic acid (DMPA). The catalyst is dibutyl tin dilaurate. The solvent is ethyl acetate.

[0149] A preparation method of a graphene modified polyurethane oligomer, comprising the following steps:

[0150] The polyether polyol, polyisocyanate and chain extender are stirred uniformly at a temperature of 45℃; single-layer graphene oxide is added, the temperature is raised to 58℃, and stirring is performed for 8 min; the catalyst is added, the temperature is raised to 78℃, and reaction stirring is performed for 2.8 h; the temperature is lowered to 56℃, the photocuring reaction monomer is added dropwise, and stirring is continued for 4 h, then the temperature is lowered to 43℃, the solvent is added, and stirring is performed for 0.6 h, thereby obtaining the graphene-modified polyurethane oligomer.

[0151] The present comparative example also provides a strong ultraviolet-resistant high-wear-resistance UV coating, raw materials of which include UV light oil, light stabilizer, dispersant and graphene-modified polyurethane oligomer in a weight ratio of 100:1:2:10.

[0152] The light stabilizer is Tinuvin 900. The dispersant is formed by mixing 12% fumed silica in ethyl acetate as a solvent.

[0153] The preparation method of the above strong ultraviolet-resistant high-wear-resistance UV coating comprises the following steps: adding the UV light oil and the light stabilizer into a reaction kettle, uniformly mixing at a temperature of 33℃ and a rotation speed of 900 r / min; then adding the dispersant, keeping the rotation speed unchanged, and mixing for 6 min; then adding the graphene-modified polyurethane oligomer, increasing the rotation speed to 1500 r / min, and mixing for 0.8 h; finally, increasing the temperature of the reaction kettle to 100℃, keeping a slight negative pressure in the kettle, keeping the rotation speed unchanged, and mixing for 1.5 h, thereby obtaining the finished product UV coating.

[0154] Comparative Example 9: conventional UV light oil ZU52301.

[0155] Performance detection

[0156] The coatings obtained in the application examples and comparative examples are subjected to relevant performance detection, and the specific operation is as follows:

[0157] The wood floor substrate surface is coated by rolling, the coating thickness is 20 μm, the curing lamp uses one lamp and one mercury, and the curing time is 30 s. The obtained sample is subjected to 1000 h ultraviolet aging experiment, the yellowing resistance performance (GB / T23983-2009) is tested, and the surface wear resistance (1000 g / 500 r) test (GB / T1768-2006), the paint film hardness test (pencil hardness GB / T6739-2022) and the paint film adhesion test (crosshatch method ISO2409-2024) are carried out; the detection results are shown in Table 1.

[0158] Table 1 Performance detection table of examples and comparative examples

[0159] Test object Resistance to yellowing ΔE Wear resistance g Curing efficiency Paint film hardness Adhesion Application example 1 1.29 0.008 Normal 4H 0 rank Application example 2 1.26 0.007 Normal 4H 0 rank Application example 3 1.18 0.008 Normal 4H 0 rank Application example 4 1.23 0.006 Normal 4H 0 rank Comparative example 1 4.45 0.026 Normal 2H 1 rank Comparative example 2 3.86 0.089 Incompletely cured / / Comparative example 3 4.32 0.028 Normal 2H 3 rank Comparative example 4 4.23 0.024 Normal 2H 3 rank Comparative example 5 1.56 0.019 Normal 3H 0 rank Comparative example 6 1.66 0.018 Normal 1H 0 rank Comparative example 7 1.68 0.022 Normal 2H 0 rank Comparative example 8 3.70 0.029 Normal 2H 0 rank Comparative example 9 5.28 0.023 Normal 1H 0 rank

[0160] Firstly, by comparing the performance of application examples 1-4 and comparative example 9, it can be seen that after adding the graphene modified polyurethane oligomer prepared in the present application to the UV coating, the wear resistance, hardness and UV resistance of the coating can be effectively improved, and the curing efficiency and film formation of the coating are not affected.

[0161] Further, by analyzing the performance of comparative example 1, it is found that after directly adding graphene oxide to the coating, the curing efficiency of the coating is not affected, but the UV resistance, wear resistance, hardness and adhesion of the coating are decreased to different degrees. This shows that the performance of the coating of the present application is improved because the graphene modified polyurethane oligomer prepared in the present application is added, which improves the performance of the coating as a whole. For the graphene modified polyurethane oligomer of the present application, the graphene is successfully introduced into the coating system, and the dispersibility of the graphene in the system is effectively improved, and a structure in which the graphene is interpenetrated in the polyurethane network is formed, thereby making the graphene fully play its UV resistance in the coating, and the oligomer effectively improves the comprehensive performance of the coating. In addition, by analyzing the performance of comparative example 2, it is found that the amount of graphene modified polyurethane oligomer in the coating should not be too much, otherwise the curing of the coating will be affected, and the UV resistance and wear resistance will also be greatly reduced.

[0162] For the preparation of the graphene modified polyurethane oligomer, first, comparative examples 3-7 are analyzed. In the technical scheme of comparative example 3, oxidized graphite is used instead of single-layer graphene oxide; in the technical schemes of comparative examples 4 and 5, the carbon-oxygen ratio of single-layer graphene oxide is too high and too low, respectively; in the technical scheme of comparative example 6, the molecular weight of the polyether polyol used is too high; and in the technical scheme of comparative example 7, ethylene oxide polyether diol (molecular weight 600) is used as the polyether polyol. By observing the performance of comparative examples 3-7, it is found that the performance of the coating is decreased to different degrees, among which the performance of comparative examples 3 and 4 is decreased more seriously. This shows that in the graphene modified polyurethane oligomer, the raw material system has a very important effect on the performance of the final product, and the use of graphene oxide with too high carbon-oxygen ratio and graphene oxide has a greater impact on the oligomer. In the technical scheme of the present application, single-layer graphene oxide and polyether polyol have good reactivity and high reaction efficiency, and can disperse each other, so that the graphene is interpenetrated in the polyurethane network and connected by hydrogen bonds, non-covalent bonds, ester bonds or ether bonds and covalent bonds, and polyurethane, thereby greatly improving the comprehensive performance of the coating.

[0163] Further, the performance analysis of Comparative Example 8 finds that in the preparation step of graphene modified polyurethane oligomer, Comparative Example 8 first reacts polyether polyol, polyisocyanate and chain extender, and then adds single-layer graphene oxide. Comparative Example 8 has a certain degree of decline in yellowing resistance and wear resistance compared with the examples, and the film hardness also declines. This is because in the technical solution of the present application, the single-layer graphene oxide is pre-reacted with the polyether polyol and the chain extender, so that the graphene is interpenetrated in the polyurethane network to obtain an oligomer with excellent performance. In the reaction process of Comparative Example 8, the graphene cannot be well interpenetrated in the polyurethane network, and the coating performance cannot be well improved.

[0164] Therefore, in the preparation process of the oligomer of the present application, the raw material system is very important, and in addition, the suitable reaction step makes the graphene interpenetrated in the structure of the polyurethane network, which can well improve the performance of the coating.

[0165] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A graphene-modified polyurethane oligomer, characterized in that: The polyurethane modified polymer is made from raw materials including polyether polyol, single-layer graphene oxide, polyisocyanate, photocurable reaction monomer, chain extender, catalyst and solvent; the carbon-oxygen ratio of the single-layer graphene oxide is ≤4; in the graphene-modified polyurethane oligomer, graphene is interspersed in the polyurethane network and connected to the polyurethane through covalent bonds and non-covalent bonds.

2. A graphene-modified polyurethane oligomer according to claim 1, characterized in that: The weight ratio of the polyether polyol, single-layer graphene oxide, polyisocyanate, photocuring reaction monomer, chain extender, catalyst and solvent is (20-30): (1-2): (10-15): (5-10): (60-80): (0.5-1): (120-150).

3. A graphene-modified polyurethane oligomer according to claim 1, characterized in that: The polyether polyol includes at least one of pentaerythritol-propylene oxide polyether tetraol and pentaerythritol-ethylene oxide polyether tetraol; and the molecular weight of the polyether polyol is 600-1000.

4. The graphene-modified polyurethane oligomer according to claim 1, wherein: The carbon-oxygen ratio of the single-layer graphene oxide is 3-4.

5. The graphene-modified polyurethane oligomer according to claim 1, wherein: The photocurable reaction monomer includes at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, and dipropylene glycol diacrylate.

6. The graphene-modified polyurethane oligomer according to claim 1, wherein: The chain extender includes at least one of 2,2-dihydroxymethylpropionic acid, 2,2-dihydroxymethylbutanoic acid or 2,3-dihydroxysuccinic acid.

7. The graphene-modified polyurethane oligomer according to claim 1, wherein: The solvent includes at least one of ethyl acetate and isoamyl butyrate.

8. The graphene-modified polyurethane oligomer according to claim 1, wherein: The polyisocyanate includes at least one of HDI trimer, IPDI, and H12MDI.

9. A method for preparing a graphene-modified polyurethane oligomer according to any one of claims 1 to 8, characterized in that: The following steps are involved: The polyether polyol, monolayer graphene oxide and chain extender are stirred uniformly at a temperature of 40-45°C; polyisocyanate is added, the temperature is raised to 55-60°C, and stirred for 5-10 minutes; then a catalyst is added, the temperature is raised to 75-80°C, and the reaction is stirred for 2.5-3 hours; the temperature is lowered to 55-60°C, a photocurable reaction monomer is added dropwise, and stirring is continued for 3-5 hours, then the temperature is lowered to 40-45°C, a solvent is added, and stirring is continued for 0.5-1 hour to obtain a graphene-modified polyurethane oligomer.

10. Use of the graphene-modified polyurethane oligomer according to any one of claims 1 to 8 in UV coatings.