阅读说明：本技术 含羟基自消光水性聚氨酯及由其组成的高性能自消光涂料 (Hydroxyl-containing self-extinction waterborne polyurethane and high-performance self-extinction coating composed of same ) 是由 韦子遨 韦雨春 于 2020-08-10 设计创作，主要内容包括：本发明涉及一种含羟基自消光水性聚氨酯的制备及由其组成的高性能自消光涂料。该含羟基自消光水性聚氨酯,按重量份计包括以下组分：聚合物多元醇15～25重量份；异氰酸酯单体5～15重量份；二羟甲基丙酸或二羟甲基丁酸0.2～0.8重量份；PH值调节剂0.1～0.7重量份；羟烷基乙二胺扩链剂0.5～3.0重量份；二烷基醇胺封端剂0.1～4.0重量份；二胺磺酸盐扩链剂0.2～1.5重量份；催化剂0.01～0.05重量份；有机溶剂2～10重量份；去离子水50～80重量份；增稠剂0.1～3重量份。其特点是在水性聚氨酯的后扩链阶段通过羟烷基乙二胺扩链和二烷基醇胺封端,在聚合物分子链上引入羟基,以提供较多的交联点。当加入水分散型聚异氰酸酯或氨基树脂交联剂时可制备出高性能的双组份或单组份自消光水性涂料。(The invention relates to a preparation method of hydroxyl-containing self-extinction waterborne polyurethane and a high-performance self-extinction coating composed of the hydroxyl-containing self-extinction waterborne polyurethane. The hydroxyl-containing self-extinction waterborne polyurethane comprises the following components in parts by weight: 15-25 parts by weight of polymer polyol; 5-15 parts by weight of an isocyanate monomer; 0.2 to 0.8 part by weight of dimethylolpropionic acid or dimethylolbutyric acid; 0.1-0.7 parts of pH value regulator; 0.5-3.0 parts by weight of a hydroxyalkyl ethylenediamine chain extender; 0.1-4.0 parts by weight of a dialkanolamine end-capping agent; 0.2-1.5 parts by weight of diamine sulfonate chain extender; 0.01-0.05 parts by weight of a catalyst; 2-10 parts by weight of an organic solvent; 50-80 parts by weight of deionized water; 0.1 to 3 parts by weight of a thickener. The method is characterized in that hydroxyl is introduced into a polymer molecular chain through hydroxyalkyl ethylenediamine chain extension and dialkyl alcohol amine end capping in the post chain extension stage of the waterborne polyurethane so as to provide more crosslinking points. When water dispersible polyisocyanate or amino resin cross-linking agent is added, high-performance two-component or one-component self-extinction water-based paint can be prepared.)

1. The hydroxyl-containing self-extinction waterborne polyurethane is characterized in that: the paint consists of the following components in percentage by weight:

15-25 parts by weight of polymer polyol

5-15 parts by weight of isocyanate monomer

0.2 to 0.8 part by weight of dimethylolpropionic acid or dimethylolbutyric acid

0.1 to 0.7 part by weight of a pH regulator

0.5 to 3.0 parts by weight of a hydroxyalkyl ethylenediamine chain extender

0.1-4.0 parts by weight of a dialkanolamine end-capping agent

0.2-1.5 parts by weight of diamine sulfonate chain extender

0.01 to 0.05 part by weight of a catalyst

2-10 parts by weight of organic solvent

50-80 parts by weight of deionized water

0.1-3 parts by weight of a thickener;

wherein the hydroxyl content of the polyurethane is 0.5-2.5% in terms of dry solid parts;

the preparation method of the waterborne polyurethane is characterized by comprising the following steps: (a) firstly, adding polymer polyol, isocyanate monomer, dimethylolpropionic acid or dimethylolbutyric acid, catalyst and organic solvent into a reaction kettle according to the formula amount, wherein the isocyanate monomer is excessive and reacts at 50-90 ℃ until the NCO content reaches or is less than the theoretical value; (b) cooling the polymer to 20-40 ℃, adding a pH value regulator such as triethylamine or N-methylmorpholine according to the formula amount, and dispersing the reactant into deionized water according to the formula amount at a high speed; (c) adding hydroxyalkyl ethylenediamine chain extender with the formula amount, and reacting for 5-8 minutes at 10-50 ℃; (d) then adding a diamine sulfonate chain extender with the formula amount, and reacting for 5-8 minutes at 10-50 ℃; (e) finally adding a dialkanolamine end-capping agent in a formula amount, and reacting for 30-60 minutes at 10-50 ℃; (f) in the step (a), if the added organic solvent is a high boiling point solvent such as N-methyl pyrrolidone and the like, the solvent is not required to be separated, the prepared thickening agent for the aqueous polyurethane is thickened, and if the added solvent is acetone and butanone, the pressure reduction separation is finally carried out, and the prepared thickening agent for the aqueous polyurethane is thickened.

2. The aqueous polyurethane of claim 1, wherein: the polymer polyol is conventional polyester polyol, polytetrahydrofuran ether Polyol (PTMG), ethylene oxide polyether Polyol (PEG), propylene oxide Polyether Polyol (PPG), polycaprolactone Polyol (PCL), polycarbonate Polyol (PCD) and polyacrylate Polyol (PA), the molecular weight of the polymer polyol is 500-3000, the functionality of the polymer polyol is 2-3, and the polymer polyol can be used independently or as a mixture.

3. The aqueous polyurethane of claim 1, wherein: the isocyanate monomer is one or a mixture of more of isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), Xylylene Diisocyanate (XDI), 2, 4-and/or 2, 6-Toluene Diisocyanate (TDI).

4. The aqueous polyurethane of claim 1, wherein: the hydroxyalkyl ethylenediamine chain extender is one or a mixture of more of hydroxyethyl ethylenediamine, N-dihydroxyethyl ethylenediamine, hydroxypropyl ethylenediamine and ethylenediamine-dibutyl alcohol.

5. The aqueous polyurethane of claim 1, wherein: the dialkyl hydramine end-capping agent is one or a mixture of diethanol amine, diisopropanolamine and dibutanolamine.

6. The aqueous polyurethane of claim 1, wherein: the diamine sulfonate chain extender is one or a mixture of two of 2- [ (2-aminoethyl) amino ] ethanesulfonic acid sodium salt and 3- [ (2-aminoethyl) amino ] propanesulfonic acid sodium salt.

7. The aqueous polyurethane of claim 1, wherein: the organic solvent is one or a mixture of several of N-methyl pyrrolidone, N-ethyl pyrrolidone, dimethyl acetamide, dimethyl formamide, acetone or butanone.

8. The aqueous polyurethane of claim 1, wherein: the thickening agent is one or a mixture of two of alkali swelling polyacrylic acid thickening agent or associative hydrophobic modified polyurethane thickening agent.

9. The hydroxyl-containing self-extinction aqueous polyurethane of claim 1, which is used for preparing high-performance two-component or one-component self-extinction aqueous coating, and is characterized in that: the two-component coating prepared by adding the water dispersible polyisocyanate crosslinking agent with the weight percentage of 5-20% of the hydroxyl-containing self-extinction waterborne polyurethane can be cured at room temperature, the one-component coating prepared by adding the amino resin crosslinking agent with the weight percentage of 5-18% of the hydroxyl-containing self-extinction waterborne polyurethane can be cured by baking at the temperature of 120 ℃ and 140 ℃ for 20min, the two coatings can both obtain a low-gloss coating with excellent water resistance and solvent resistance, the gloss of the coating at an angle of 60 ℃ can be lower than 1.0, and the two coatings can be widely applied to various base materials such as leather, fabrics, wood, metal, cement, plastic and the like.

Technical Field

The invention relates to the field of high polymer materials, in particular to a preparation method of hydroxyl-containing waterborne polyurethane with self-extinction performance and a method for preparing a high-performance self-extinction coating by matching the hydroxyl-containing waterborne polyurethane with a cross-linking agent.

Background

The environmental properties of waterborne polyurethanes are well known. The development of the relevant matting coatings has been rapid in recent years and the optical properties of the coatings have become increasingly important. Usually, the matting coating can be obtained by adding a matting agent, such as inorganic or organic matting agents like silica, polyurethane, polyacrylate particles, etc., but the coating with the added matting agent usually has the disadvantages of poor abrasion resistance, poor transparency, poor matting effect, etc. In addition, the external flatting agent has the defects of easy thickening, sedimentation and agglomeration, reduced coating film physical property, uneven material surface optical effect and the like in the application of a water-based coating system.

At present, many self-extinction waterborne polyurethanes researched and reported are usually single-component polyurethane, and do not contain external crosslinking groups such as hydroxyl groups. Patents CN102112510B and CN103865031B use aqueous dispersions of anionic polyurethanes with hydrophilic groups dimethylolpropionic acid and diamine sulfonates as post-chain extenders to stabilize the polymer emulsion and maintain redispersibility of the polymer particles. Patents CN110204682B and WO2012020026a1 disclose a process for preparing aqueous non-ionic polyurethane dispersions having a large particle size and a broad particle size distribution, which are easily redispersible and whose polymer coating films have a low gloss. Patents CN106519133A and WO2016102596a1 obtain polyurethane-vinyl polymer hybrid particles by radical polymerization of at least one vinyl monomer in the presence of polyurethane, which is said to significantly improve the transparency of the polymer coating film while self-matting.

The self-extinction water-based resin has a very limited improvement in performance due to a small number of effective crosslinking points even when a water-dispersible polyisocyanate crosslinking agent and a azapyridine crosslinking agent are added. In order to overcome the problems, the invention designs the self-extinction waterborne polyurethane with high-content hydroxyl, and the hydroxyl is crosslinked by adding water dispersible polyisocyanate or amino resin crosslinking agent to form a reticular macromolecular structure with higher density, thereby obtaining the self-extinction waterborne polyurethane coating with high performance.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method of hydroxyl-containing self-extinction waterborne polyurethane. The coating film has low gloss, and the molecular chain of the polymer contains more hydroxyl groups. When a cross-linking agent is added, the cross-linking agent can provide more cross-linking points and has excellent physicochemical properties after being cured into a film.

The invention also aims to provide the application of the waterborne polyurethane and a preparation method of the coating thereof. By using the waterborne polyurethane and matching with a cross-linking agent, a high-performance double-component or single-component self-extinction waterborne coating can be prepared.

In order to achieve the above purpose, the invention is realized by the following technical scheme:

the hydroxyl-containing self-extinction waterborne polyurethane is characterized in that: the paint consists of the following components in percentage by weight:

15-25 parts by weight of polymer polyol

5-15 parts by weight of isocyanate monomer

0.2 to 0.8 part by weight of dimethylolpropionic acid or dimethylolbutyric acid

0.1 to 0.7 part by weight of a pH regulator

0.5 to 3.0 parts by weight of a hydroxyalkyl ethylenediamine chain extender

0.1-4.0 parts by weight of a dialkanolamine end-capping agent

0.2-1.5 parts by weight of diamine sulfonate chain extender

0.01 to 0.05 part by weight of a catalyst

2-10 parts by weight of organic solvent

50-80 parts by weight of deionized water

0.1-3 parts by weight of a thickener;

wherein the hydroxyl content of the polyurethane is 0.5-2.5% in terms of dry solid parts, and the calculation method is as follows:

OH%: is a hydroxyl content as described above; m_OH: the mole number of the grafted hydroxyl; w: is the weight of the polyurethane emulsion, and the unit is gram; w%: is the solid content of the polyurethane emulsion.

On the basis of the above scheme, the polymer polyol is conventional polyester polyol, polytetrahydrofuran ether Polyol (PTMG), ethylene oxide polyether Polyol (PEG), propylene oxide Polyether Polyol (PPG), polycaprolactone Polyol (PCL), polycarbonate Polyol (PCD), and polyacrylate Polyol (PA). The functionality is 2-3, the molecular weight is 500-3000, preferably 1000-2000. They may be used alone or as a mixture.

On the basis of the scheme, the isocyanate monomer is one or a mixture of more of isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), Xylylene Diisocyanate (XDI), 2, 4-and/or 2, 6-Toluene Diisocyanate (TDI). Preference is given to isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI)

On the basis of the scheme, the dimethylolpropionic acid or dimethylolbutyric acid is a hydrophilic monomer, and preferably dimethylolpropionic acid.

On the basis of the scheme, the PH value regulator is triethylamine or N-methylmorpholine, and triethylamine is preferred.

Based on the scheme, the hydroxyalkyl ethylenediamine chain extender is prepared by dispersing reactants in water in the early prepolymerization process and then adding-NH at both ends of the reactants₂or-NH and-NCO at two ends of the prepolymer to carry out chain extension reaction, and hydroxyl-OH is introduced into the polymer moleculeOn the daughter strand. The following were used:

the hydroxyalkyl ethylenediamine chain extender can be one or a mixture of more of hydroxyethyl ethylenediamine, hydroxypropyl ethylenediamine, N-dihydroxyethyl ethylenediamine and ethylenediamine-dibutyl alcohol. Hydroxyethyl ethylenediamine is preferred.

On the basis of the scheme, the dialkanolamine end-capping agent is one or a mixture of diethanolamine, diisopropanolamine and dibutanolamine. Diethanolamine is preferred. After the pre-polymerization reactant is dispersed in water in the early stage, besides introducing hydroxyl-OH in the middle of a polymer macromolecular chain by using a hydroxyalkyl ethylenediamine chain extender, secondary amine containing two hydroxyl-OH can be used for blocking the polymer so as to improve the content of the hydroxyl-OH on the polymer macromolecular chain. The following were used:

on the basis of the scheme, the diamine sulfonate chain extender is selected from one or a mixture of two of sodium 2- [ (2-aminoethyl) amino ] ethanesulfonate and sodium 3- [ (2-aminoethyl) amino ] propanesulfonate. Preference is given to sodium 2- [ (2-aminoethyl) amino ] ethanesulfonate.

On the basis of the scheme, the catalyst is organic tin, organic bismuth or organic silver. Preferably an organobismuth catalyst.

On the basis of the scheme, the organic solvent is one or a mixture of N-methyl pyrrolidone, N-ethyl pyrrolidone, dimethyl acetamide, dimethyl formamide, acetone or butanone. Acetone is preferred.

On the basis of the scheme, the thickening agent is one or a mixture of two of an alkali swelling polyacrylic acid thickening agent or an associated hydrophobic modified polyurethane thickening agent. Preferably alkali-swellable polyacrylic acid thickeners.

The preparation method of the waterborne polyurethane mainly comprises the following steps: (a) firstly, adding polymer polyol, isocyanate monomer, dimethylolpropionic acid or dimethylolbutyric acid, catalyst and organic solvent into a reaction kettle according to the formula amount, wherein the isocyanate monomer is excessive and reacts at 50-90 ℃ until the NCO content reaches or is less than the theoretical value; (b) cooling the polymer to 20-40 ℃, adding a pH value regulator such as triethylamine or N-methylmorpholine according to the formula amount, and dispersing the reactant into deionized water according to the formula amount at a high speed; (c) adding hydroxyalkyl ethylenediamine chain extender with the formula amount, and reacting for 5-8 minutes at 10-50 ℃; (d) then adding a diamine sulfonate chain extender with the formula amount, and reacting for 5-8 minutes at 10-50 ℃; (e) finally adding a dialkanolamine end-capping agent in a formula amount, and reacting for 30-60 minutes at 10-50 ℃; (f) if the organic solvent added in the step (a) is a high boiling point solvent such as N-methyl pyrrolidone, the solvent does not need to be separated, and the prepared waterborne polyurethane is thickened by the thickening agent. If the added solvent is acetone and butanone, and finally decompression separation is carried out, the obtained aqueous polyurethane is thickened by the thickening agent.

Aiming at the application of the waterborne polyurethane, the waterborne polyurethane is used for preparing high-performance two-component or one-component self-extinction waterborne coating. The double-component coating prepared by adding the water dispersible polyisocyanate crosslinking agent containing 5-20% by weight of hydroxyl self-extinction waterborne polyurethane can be cured at room temperature. And adding an amino resin cross-linking agent which contains 5-18 wt% of hydroxyl self-extinction waterborne polyurethane to prepare the single-component coating, and baking the single-component coating at the temperature of 120-140 ℃ for 20min for curing. Both of the above result in low gloss coatings with excellent water and solvent resistance, which can have a gloss of less than 1.0 at an angle of 60 degrees. They can be widely applied to various substrates such as leather, fabric, wood, metal, cement, plastic and the like.

The invention has the beneficial effects that: the invention obtains the hydroxyl-containing waterborne polyurethane with self-extinction performance, and the two-component or single-component self-extinction waterborne coating with excellent physical and chemical properties can be prepared by adding the water dispersible polyisocyanate or the amino resin cross-linking agent.

Detailed Description