CN101550224B - Preparation method of cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent - Google Patents

Abstract

The invention provides a preparation method of a cationic polyurethane/inorganic nano material organic-inorganic hybrid finishing agent. The main composition of the finishing agent is calculated by mass percentage: 20-50% of polyurethane and 50-80% of deionized water. The preparation method of the coating agent mainly includes: preparing a polyurethane prepolymer from a diol and a diisocyanate; adding an in-situ dispersed chain extender and inorganic nanoparticles to extend the chain of the prepared polyurethane prepolymer; Neutralize, emulsify, remove solvent. The invention adopts the in-situ polymerization method to prepare the organic-inorganic hybrid finishing agent, and does not use any precursor in the preparation process, which fundamentally solves the problem that the sol-gel method uses expensive and highly toxic precursors, which is easy to cause serious damage to the environment. It solves the problem of pollution, and also solves the problem of uneven dispersion and easy agglomeration between inorganic nanoparticles and polyurethane in the blending method. The prepared coating agent has good application performance and is convenient for construction and operation.

Description

Preparation method of cationic polyurethane/inorganic nanomaterial organic-inorganic hybrid coating agent

Technical field:

The invention relates to a cationic polyurethane nano-finishing agent, in particular to a preparation method of a water-based polyurethane/inorganic nano-material organic-inorganic hybrid finishing agent. The finishing agent can be applied to natural leather and synthetic leather finishing and other fields.

technical background:

Polyurethane coatings are widely used in the coating of infrastructure, furniture, vehicles, leather and other products due to their excellent properties such as chemical resistance, wear resistance, good decoration, and strong adhesion. Currently, solvent-based polyurethanes are widely used in production and construction. A large amount of volatile organic compounds (VOC) are produced in the process, which seriously endangers people's health and destroys the environment and ecological balance. Water-based polyurethane coatings are non-flammable, non-toxic, low-pollution, easy to store, and convenient to use. They have comprehensive properties comparable to solvent-based polyurethanes. In recent years, they have been successfully used in leather finishing, paper coating, chemical building materials, automobile coating and other fields. , has the development trend of gradually replacing solvent-based polyurethane, and has become an important direction of polyurethane research and development.

The vast majority of traditional leather finishing agents are anionic, and the crust leather before coating is also mostly negatively charged, there is little or no natural affinity between the finishing material and the crust leather, and the finishing agent can only rely on adhesive force to adhere to On the leather; while the cationic finishing agent can strengthen the adhesion between the finishing agent and the leather by the attraction of negative and positive charges, the adhesion is better, and the finishing effect is more excellent. The isoelectric point of cationic polyurethane is similar to that of leather fiber, and it has good permeability and adhesion to chrome-tanned, vegetable-tanned and resin-tanned leather. It can be applied in "sandwich" finishing system, "full cationic" finishing system, The "semi-cationic" finishing system can effectively cover grain defects, fill and even out the leather surface, endow the leather with a soft, natural, smooth and delicate feel, further improve the quality of the leather, and create a higher market value.

One-component waterborne polyurethane cannot reach the level of solvent-based or two-component polyurethane in hardness, water resistance, solvent resistance, gloss, etc., which limits its further application. Combining with inorganic nanomaterials is to improve its comprehensive performance effective way. Inorganic nanomaterials have the characteristics of small size effect, large specific surface, high surface energy and insufficient surface coordination, which make them easy to bond with oxygen in polyurethane and improve molecular bonding force: at the same time, they are easy to distribute to the voids of polymer chains Among them, the strength, toughness, ductility, water resistance, etc. of the material can be greatly improved; and the quantum size of the nanomaterial and the macroscopic quantum tunneling effect make it produce silting effect, which can go deep into the unsaturated bond of the polyurethane molecular chain Nearby, and interact with the electron cloud of the unsaturated bond, thereby improving the thermal stability, light stability and chemical stability of the polyurethane material, and achieving the purpose of improving the anti-aging performance and chemical resistance of the product.

The blending method commonly used to prepare nano-polyurethane composite materials is only a simple physical mixing between inorganic nano-materials and polyurethane, and there are problems of uneven dispersion of inorganic particles and easy agglomeration; while the precursors used in the sol-gel method are expensive Moreover, it is highly toxic and will cause serious environmental pollution. With the development of economy and technology and the strengthening of people's awareness of environmental protection, the existing technology for preparing nano-polyurethane can no longer provide people with polyurethane coating products that meet modern environmental protection requirements. In practice, scientific and technological personnel are required to develop new nano-polyurethane preparation technology to provide Polyurethane finishing products that meet the requirements of environmental "sustainable development".

Invention content:

For the present situation of polyurethane finishing agent prior art, the object of the present invention aims to provide a kind of inorganic particle dispersion uniform, prepare cationic polyurethane/inorganic nano material organic-inorganic hybrid finishing agent and preparation method thereof without any precursor, to solve In the prior art of preparing nano-polyurethane finishing agents, the dispersion of inorganic particles is easy to agglomerate and uneven, and the precursor used is expensive and highly toxic, and it is easy to cause serious pollution to the environment.

The basic idea of the invention is to prepare the organic-inorganic hybrid finishing agent by adopting the in-situ polymerization method which combines the advantages of physical blending and chemical crosslinking methods. Nanoparticles can be uniformly dispersed in the polyurethane matrix by in-situ polymerization, and effective organic-inorganic hybridization can be produced at the interface between nanomaterials and polyurethane matrix without any precursors to reduce production costs and meet modern Environmental requirements.

The basic idea of the present invention is to firstly prepare polyurethane prepolymer, then use in-situ polymerization to insert nanomaterials, introduce cationic hydrophilic groups through chain extension, and finally neutralize and emulsify the prepared cationic polyurethane/inorganic nanomaterial organic-inorganic Hybrid finish.

The method for preparing cationic polyurethane/inorganic nanomaterial organic-inorganic hybrid finishing agent provided by the present invention specifically includes the following preparation steps:

(1) Dihydric alcohols with a molecular weight of 600-4000 are dehydrated at a vacuum degree of 0.05-0.1 MPa and a temperature of 110-130°C for 30-60 minutes, then cooled to a room temperature not higher than 40°C, and the molar ratio n _NCO /n _OH = 2~4 Add diisocyanate, add a catalyst with 0.3%~1.0% diisocyanate mass, react at 60°C~90°C under the protection of nitrogen, and cool down to room temperature not higher than 40°C after full reaction, that is, the polyurethane prepolymerized thing;

(2) The prepared polyurethane prepolymer is added with 5-15% solvent of diol and diisocyanate mass total amount, 2-10% inorganic nanoparticle material dispersed in situ, 2-10% chain extender and 2-10% 10% tertiary amino hydroxyl compound, carry out chain extension reaction at 50°C-80°C under the protection of nitrogen, and cool down to 30-55°C after fully reacting;

(3) Add a salt-forming agent to the polyurethane prepolymer after chain extension according to the degree of neutralization of 80% to 100%, and disperse it into deionized water after thorough mixing. MPa decompressed distillation to remove the solvent, that is, the cationic polyurethane/inorganic nano material organic-inorganic hybrid coating agent is obtained.

The prepared cationic polyurethane/inorganic nanometer material organic-inorganic hybrid finishing agent mainly consists of 20-50% of polyurethane and 50-80% of deionized water in terms of mass percentage.

In the above technical solution, the inorganic nanoparticle material can be selected from nano-SiO ₂ , nano-TiO ₂ , nano-ZnO, nano-CaCO ₃ , nano-Al ₂ O ₃ , nano-montmorillonite and nano- clay etc. You can choose one of them, or two or more of them.

In the above technical scheme, the tertiary amino hydroxyl compound (that is, R ₃ in the structural formula (I)) can be selected from triethanolamine, N-methyldiethanolamine (MDEA), N-ethyldiethanolamine (N-EDEA ), N-propyldiethanolamine (N-PDEA), N-benzyldiethanolamine (N-BDEA), tert-butyldiethanolamine (t-BuDEAt), dimethylethanolamine, bis(2-hydroxyethyl) Benzylaniline (BHBA) and bis(2-hydroxypropyl)aniline (BHPA), etc. Generally, one of them is selected.

In the above technical solution, the salt-forming agent (H ⁺ X ⁻ ) can be selected from organic acids, inorganic acids and alkylating agents. Generally, one of them is selected. Among them, the inorganic acid is preferably hydrochloric acid, the organic acid is preferably acids such as CH ₃ COOH, and the alkylating agent is preferably CH ₃ I alkylating agent and epichlorohydrin alkylating agent.

In the above technical solution, the diisocyanate (ie R ₄ in the structural formula (II)) may be selected from aromatic diisocyanate, aliphatic diisocyanate and alicyclic diisocyanate. Generally, one of them is selected. Preferred are toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), and the like.

In the above technical solution, the diol with a molecular weight of 600-4000 (that is, R ₅ in the structural formula (II)) can be selected from polyether diol, polyester diol and polycarbonate diol. One of them can be used, and a mixture of two or more of them can also be used. Polyoxypropylene diol (PPG), polytetrahydrofuran diol (PTG), polycaprolactone diol (PCL), polycarbonate diol (PCDL) and the like are preferable. Diols or polyols with a molecular weight of less than 300 may be selected from 1,4-butanediol, diethylene glycol, neopentyl glycol, ethylene glycol, 1,2 propylene glycol, 1,6 hexanediol, tris Methylol propane, glycerin and pentaerythritol, etc. One or more of them can be used. Preference is given to diethylene glycol, neopentyl glycol and trimethylolpropane.

In the above technical solution, the catalyst may be selected from tertiary amine catalysts and organotin catalysts, and the solvent may be selected from ketone organic solvents.

In the above technical scheme, the addition amount of inorganic nanoparticle material, chain extender and tertiary amino hydroxyl compound is related to the formulation of dibasic alcohol and diisocyanate, and changes greatly with the change of formulation, and their addition amount is controlled at The range of 5-10% by mass of dihydric alcohol and diisocyanate is suitable. The method of adding inorganic nanomaterials, chain extenders, and tertiary amino hydroxyl compounds is best to mix them in a solvent, disperse them evenly with ultrasonic waves, and then add them to the polyurethane prepolymer in batches for chain extension. reaction.

The invention adopts the in-situ filling technology, first mixes the inorganic nano material with the chain extender and the tertiary amino hydroxyl compound, disperses evenly by ultrasonic wave and inserts the polyurethane molecule, and prepares the cationic polyurethane/inorganic nano material organic-inorganic hybrid finishing agent , the preparation process does not require the highly toxic and expensive precursors used in the sol-gel method, and it can also make the organic-inorganic hybrid of nanomaterial particles in the polymer, and it will not occur nanomaterials like the blending method. The agglomeration of particles can effectively maintain the nano properties of the particles, and improve the mechanical and thermodynamic properties such as hardness, strength, and glass transition temperature of the composite material, as well as the magnetic, optical, and aging resistance properties.

The cationic polyurethane/inorganic nanomaterial organic-inorganic hybrid finishing agent prepared by the present invention is a translucent emulsion with a solid content of 20% to 50%, a pH of 5.5 to 7.0, and a room temperature storage time of up to one year. The finishing agent is used for For leather finishing, compared with the commonly used anionic finishing agents, the adhesion between the finishing agent and the leather can be strengthened by the attraction of anion and cation charges. The coating has better adhesion to the leather fiber and has a good relationship with the anionic finishing agent. Capacitance, can be applied to the "sandwich" finishing system together; compared with the one-component cationic polyurethane coating, it can improve the water resistance, solvent resistance, light resistance, strength, hardness and other properties of the finished leather, and has good permeability and adhesion. The finished leather is soft and delicate, the surface film is extremely thin and natural, and the hand feels full, which can greatly improve the performance of the finished leather.

The cationic polyurethane/inorganic nano material organic-inorganic hybrid finishing agent prepared by the present invention and its preparation process have the characteristics of non-toxicity, low pollution, high efficiency and energy saving, and meet the requirements of modern environmental protection. The coating has good application performance and environmental protection in construction operation It is convenient and has very wide application prospects in the field of leather finishing.

Detailed ways:

The present invention will be specifically described below with reference to the embodiments, so that those skilled in the art can understand the present invention. It is necessary to point out here that the embodiments are only used to further illustrate the present invention, and cannot be interpreted as limiting the protection scope of the present invention. Those skilled in the art can make non-essential improvements to the present invention according to the above-mentioned content of the present invention And adjustments still belong to the protection scope of the present invention.

In each of the following examples, the amount percentages or parts of the components involved are all mass percentages or parts by mass unless otherwise specified.

Example 1:

(1) Preparation of polyurethane prepolymer:

Add PPG with a molecular weight of 2000 into the reaction kettle equipped with stirring, temperature control and air extraction devices, control the vacuum degree to about 0.06MPa, dehydrate at a temperature of about 130°C for about 30 minutes, cool down to about 30°C, and pass in nitrogen for about 30 minutes. , under stirring state, add IPDI according to the molar ratio n _NCO /n _OH = 3:1, and dropwise add dibutyltin dilaurate with 0.7% IPDI mass, heat up to about 80°C and react for about 90min, then cool down to about 30°C.

(2) Adding chain extenders and nanomaterials

Under the state of nitrogen protection, add acetone of 6% of the total mass of PPG and IPDI in stages, 3% of nano-SiO ₂ , 3% of diethylene glycol and 3% of N-methyldiethanolamine dispersed in situ, and heat up React at about 70°C for about 4 hours, take a sample to determine that the NCO% is below 4%, and then cool down to about 50°C.

(3) Neutralization, emulsification, desolventization

Control the temperature at about 50°C, add an appropriate amount of acetone depending on the viscosity, and add a specified amount of acetic acid according to the neutralization degree of 90%. After mixing evenly, add deionized water to emulsify and disperse for about 40 minutes, let it stand until the foam disappears, and filter it. The acetone is pumped out under a vacuum of about 0.05MPa, and the product performance and state are observed by sampling the output.

Example 2:

(1) Preparation of polyurethane prepolymer:

Add PTG with a molecular weight of 2000 into the reaction kettle equipped with stirring, temperature control and air extraction devices, control the vacuum degree to about 0.06MPa, dehydrate at a temperature of about 110°C for about 50 minutes, then cool down to about 30°C, and pass in nitrogen for about 40 minutes. While stirring, add TDI at a molar ratio of n _NCO /n _OH = 3.5:1, and dropwise add triethylenediamine of 0.5% by mass of TDI, raise the temperature to about 70°C and react for about 100 minutes, then cool down to about 30°C.

(2) Adding chain extenders and nanomaterials

Under nitrogen protection, add PTG and TDI mass total amount of 8% acetone, in-situ dispersed 4% nano-TiO ₂ , 3% neopentyl glycol and 3.5% N-ethyldiethanolamine, and heat up to 60 React at around ℃ for about 3 hours, take samples to determine that the NCO% reaches below 3%, and then gradually lower the temperature to about 50℃.

(3) Neutralization, emulsification, desolventization

Control the temperature at about 40°C, add an appropriate amount of acetone depending on the viscosity, add a specified amount of acetic acid according to the degree of neutralization of 100%, mix well, add deionized water to emulsify and disperse for about 30 minutes, let it stand until the foam disappears, and filter it. The acetone is pumped out under a vacuum of about 0.08MPa, and the product performance and state are observed by sampling the output.

Example 3:

(1) Preparation of polyurethane prepolymer:

Add PCL with a molecular weight of 1500 into the reaction kettle equipped with stirring, temperature control and air extraction devices, control the vacuum degree to about 0.08MPa, dehydrate at a temperature of about 120°C for about 40 minutes, then cool down to about 25°C, and pass in nitrogen for about 40 minutes. Under stirring state, add MDI according to the molar ratio of n _NCO /n _OH = 4:1, and add stannous octoate dropwise with 0.5% of the mass of MDI, gradually raise the temperature to about 75°C and react for about 120 minutes, then cool down to about 25°C.

(2) Adding chain extenders and nanomaterials

Under nitrogen protection state, add the acetone of PCL and MDI mass total amount 8%, the nano-montmorillonite of 5% in situ dispersion, the diethylene glycol of 4%, the trimethylol propane of 0.5%, 4% N-propyldiethanolamine, heat up to about 60°C and react for about 3 hours, take a sample to determine that the NCO% reaches below 3%, and then gradually cool down to about 40°C.

(3) Neutralization, emulsification, desolventization

Control the temperature at about 40°C, add a proper amount of acetone depending on the viscosity, add a specified amount of acetic acid according to the neutralization degree of 80%, mix well, add deionized water to emulsify and disperse for about 30 minutes, let stand until the foam disappears, filter, and then filter at about 70°C , Acetone is pumped out under a vacuum degree of about 0.05MP, and the output is sampled to observe the product performance and state.

Claims (9)

1. cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparation method is characterized in that comprising being prepared as follows step:

(1) molecular weight is 600～4000 divalent alcohol in 110～130 ℃ of vacuum tightness 0.05～0.1MPa, temperature down behind dehydration 30～60min, is cooled to not to be higher than 40 ℃ of room temperatures, in molar ratio n _NCO/ n _OH=2～4 add vulcabond, add the catalyzer of vulcabond quality 0.3%～1.0%, under nitrogen protection, react in 60 ℃～90 ℃, fully are cooled to after the reaction not to be higher than 40 ℃ of room temperatures, promptly make polyurethane prepolymer;

(2) the polyurethane prepolymer adding divalent alcohol of producing and the solvent of vulcabond quality total amount 5～15%, inorganic nano-particle material, 2～10% chainextenders and 2～10% tertiary amine groups oxy-compound of original position dispersive 2～10%; Under nitrogen protection, carry out chain extending reaction in 50 ℃～80 ℃, fully be cooled to 30～55 ℃ after the reaction;

(3) polyurethane prepolymer behind the chain extension is pressed degree of neutralization 80%～100% adding salt forming agent; Through fully being distributed in the deionized water behind the mixing; Filter the back and remove solvent, promptly make the cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent in 60～80 ℃ of temperature, vacuum tightness 0.05～0.1MPa underpressure distillation.

2. cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparation method according to claim 1 is characterized in that said inorganic nano-particle is selected from the nanometer SiO that median size is 10nm-100nm ₂, nano-TiO ₂, nano-ZnO, nanometer CaCO ₃, nanometer Al ₂O ₃, nano imvite and nano clay.

3. cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparation method according to claim 1 is characterized in that said tertiary amine groups oxy-compound is selected from trolamine, N methyldiethanol amine, N-ethyldiethanolamine, N-propyl group diethylolamine, N-benzyl diethylolamine, tertiary butyl diethylolamine, dimethylethanolamine, two (2-hydroxyethyl) benzylaniline and two (2-hydroxypropyl) aniline.

4. the preparation method of cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent according to claim 1 is characterized in that said salt forming agent is selected from organic acid, mineral acid and alkylating reagent.

5. cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparation method according to claim 1 is characterized in that said vulcabond is selected from aromatic diisocyanate, aliphatic diisocyanate and alicyclic diisocyanate.

6. cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparation method according to claim 1 is characterized in that the divalent alcohol between the said molecular weight 600～4000 is selected from polyether Glycols, the pure and mild polycarbonate diol of polyester binary.

7. cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparation method according to claim 1 is characterized in that said catalyzer is selected from tertiary amine catalyst and organic tin catalyzer.

8. cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparation method according to claim 1 is characterized in that said solvent is selected from organic solvent of ketone.

9. according to one of 8 described cation polyurethane/inorganic nanometer material organic-inorganic hybrid coating agent preparing methods of claim 1; It is characterized in that inorganic nano material, chainextender and tertiary amine groups oxy-compound mix earlier in solvent; After utilizing ultrasonic dispersing evenly, join with the mode of gradation and to carry out chain extending reaction in the polyurethane prepolymer.