阅读说明：本技术 一种封闭剂、封闭型水性树脂及其制备方法、互穿网络结构聚合物 (Sealing agent, closed water-based resin, preparation method of closed water-based resin and interpenetrating network structure polymer ) 是由 祝方明 车俊峥 于 2020-07-13 设计创作，主要内容包括：本发明公开了一种封闭剂以及采用该封闭剂封端处理的封闭型水性树脂,同时还公开了封闭型水性树脂的制备方法以及封闭型水性树脂方法和解封后获得的聚氨酯/聚丙烯酸酯互穿网络结构聚合物。本发明的封闭剂在30～50℃下就能与异氰酸酯发生封闭反应,且反应速率快,封闭效率高,并且在较低的温度(约120℃左右)下能解封闭；制备过程绿色环保,无明显异味,制备条件较为温和的特点；制得的封闭型水性树脂综合性能优良,解封闭后封闭剂FEMA经自由基聚合生成聚丙烯酸酯,并能与水性树脂形成性能互补的互穿网络结构聚合物,而基于聚氨酯和聚丙烯酸酯在性质上的互补性,所获得的互穿网络结构聚合物兼具了二者的优点。(The invention discloses a sealing agent and a closed water-based resin subjected to end sealing treatment by adopting the sealing agent, and also discloses a preparation method of the closed water-based resin, a method for preparing the closed water-based resin and a polyurethane/polyacrylate interpenetrating network structure polymer obtained after the sealing method and the deblocking. The sealing agent can perform a sealing reaction with isocyanate at 30-50 ℃, has high reaction rate and high sealing efficiency, and can be deblocked at a lower temperature (about 120 ℃); the preparation process is green and environment-friendly, no obvious peculiar smell exists, and the preparation conditions are mild; the prepared closed water-based resin has excellent comprehensive performance, the deblocking sealant FEMA generates polyacrylate through free radical polymerization after deblocking, and can form interpenetrating network structure polymer with complementary performance with the water-based resin, and the obtained interpenetrating network structure polymer has the advantages of both the polyurethane and the polyacrylate based on the complementarity of the properties.)

1. A sealant, characterized by: the chemical formula of the compound is shown as follows,

2. the sealant according to claim 1, wherein: the catalyst is prepared by esterification reaction of 2-hydroxyethyl methacrylate and formic acid by taking hydroquinone as a polymerization inhibitor and cyclohexane as a reaction medium.

3. The sealant according to claim 2, wherein: and (2) carrying out the esterification reaction in a Dean-Stark device, refluxing for 20-30 h, then carrying out reduced pressure rotary evaporation to remove cyclohexane and formic acid to obtain a liquid crude product, and then separating and purifying the crude product by adopting a column chromatography with diethyl ether and petroleum ether mixed liquor with the volume ratio of 1: 1 as eluent.

4. A blocked aqueous resin to which the blocking agent according to any one of claims 1 to 3 is applied, characterized in that: the material is prepared from the following raw materials in percentage by mass: 0-25% of polyester diol, 0-25% of polyether diol, 5-15% of isophorone diisocyanate, 0.06-0.08% of catalyst, 1-3% of 2, 2-dimethylolpropionic acid, 1-2% of trimethylolpropane, 8-10% of sealant, 1-5% of triethylamine and 50-60% of pure water, wherein the percentages of the polyester diol and the polyether diol are not 0 at the same time.

5. The blocked aqueous resin according to claim 4, wherein: the polyester dihydric alcohol is polycaprolactone dihydric alcohol, and the molecular weight is 1000-3000; the polyether diol is polyethylene glycol ether diol or polytetrahydrofuran ether diol, the molecular weight is 1000-3000, the catalyst is dibutyltin dilaurate, and the diisocyanate is isophorone diisocyanate.

6. The blocked aqueous resin according to claim 4, wherein: the chain extender is at least one selected from 2, 2-dimethylolpropionic acid and trimethylolpropane.

7. The blocked aqueous resin according to claim 4, wherein: the chain extender is composed of a chain extender A and a chain extender B, wherein the chain extender A is 2, 2-dimethylolpropionic acid, the chain extender B is trimethylolpropane, and the chain extender A is added firstly and the chain extender B is added later during system reaction.

8. A method for preparing the blocked waterborne resin of claim 7, comprising the steps of:

s1, heating polyester diol or/and polyether diol which are dried under reduced pressure to 60-90 ℃ in a nitrogen atmosphere, and simultaneously adding a small amount of catalyst for reaction for 20-40 min;

s2, adjusting the temperature to 40-60 ℃, adding an acetone solution of a water-based chain extender A for reacting for 180-300 min, and adding an acetone solution of a chain extender B for reacting for 30-60 min;

s3, adjusting the temperature to 30-50 ℃, adding a sealing agent, and reacting for 30-60 min until the content of isocyanate groups is zero;

s4, adding acetone for dilution at a constant temperature, and then adding triethylamine for reacting for 30-60 min;

s5, adjusting the temperature to room temperature, and adding pure water for dispersion;

s6, removing the acetone by reduced pressure rotary evaporation at room temperature.

9. An interpenetrating network structure polymer formed by the blocked water-based resin of any one of claims 4 to 7 after deblocking and polyacrylate, wherein: the deblocking temperature of the blocked water-based resin is 100-130 ℃, and the deblocking time is 10-30 min.

10. The polyurethane/polyacrylate interpenetrating network structure polymer according to claim 9, wherein a small amount of ammonium persulfate is added into the closed aqueous resin, the mixture is uniformly stirred, and a film is formed and is unsealed for 15min at 110 ℃.

Technical Field

The invention relates to the field of polyurethane, in particular to a water-based resin sealing agent, a closed water-based resin (also called closed water-based polyurethane) sealed by using the sealing agent and a preparation method thereof, and a polyurethane/polyacrylate interpenetrating network structure polymer formed after the sealing of the closed water-based polyurethane resin is unsealed.

Background

The closed waterborne polyurethane is a disperse system formed by water and isocyanate groups in polyurethane molecules after being closed, is stable at room temperature, can be stored for a long time, and has the advantages of low price, safety, no combustion, no toxicity, no environmental pollution and the like of common waterborne polyurethane. When the polyurethane is heated to a certain temperature, the water in the closed waterborne polyurethane volatilizes and carries out deblocking reaction, and then active isocyanate groups are generated and carry out crosslinking reaction to form cured polyurethane, so that the water resistance and the solvent resistance of the waterborne polyurethane are improved. However, the blocked waterborne polyurethane has some defects, such as poor water resistance, wear resistance, corrosion resistance and brightness, poor flexibility, elasticity and mechanical properties, especially high deblocking temperature and long deblocking time, and difficult treatment of a product after deblocking by a blocking agent, and if some blocking agents with high boiling points are left in the product after deblocking, the properties of the product are adversely affected, and the application range of the product is limited.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a sealing agent, which can perform a sealing reaction with isocyanate at 30-50 ℃, and has high reaction rate and high sealing efficiency; the blocking agent is used for blocking the waterborne resin, namely waterborne polyurethane, which is unblocked at about 120 ℃, FEMA generated by unblocking is polymerized by free radicals to generate polyacrylate, and the polyacrylate and the polyurethane can form an interpenetrating network structure polymer which has excellent mechanical property and can be applied to industries such as light textile, leather processing, coating, wood processing, building materials, papermaking, adhesives and the like.

In order to solve the technical problem, the technical scheme of the invention is a sealant (FEMA), which has the chemical formula as follows:

further preferably, the preparation method comprises the following steps: hydroquinone is used as a polymerization inhibitor, cyclohexane is used as a reaction medium, 2-hydroxyethyl methacrylate and formic acid are subjected to esterification reaction, the esterification reaction is carried out in a Dean-Stark device, after refluxing for 20-30 h, cyclohexane and formic acid are removed through reduced pressure rotary evaporation, a liquid crude product is obtained, then a mixed solution of ethyl ether and petroleum ether in a ratio of 1: 1 is used as an eluent, and the crude product is separated and purified through column chromatography, so that pure FEMA is obtained.

The other technical scheme of the invention is as follows: the closed water-based resin is prepared from the following raw materials in parts by mass: 0-25% of polyester diol, 0-25% of polyether diol, 5-15% of isophorone diisocyanate, 0.06-0.08% of catalyst, 1-3% of 2, 2-dimethylolpropionic acid, 1-2% of trimethylolpropane, 8-10% of sealant, 1-5% of triethylamine and 50-60% of pure water, wherein the percentages of the polyester diol and the polyether diol are not 0 at the same time. The resin is also aqueous polyurethane, and the subsequent contents are directly expressed by the aqueous polyurethane.

The preparation raw materials of the closed waterborne polyurethane mainly comprise seven parts of polyester and polyether dihydric alcohol, diisocyanate, a waterborne chain extender, a catalyst, a neutralizer, a sealant and pure water; the molecular weights of polyester and polyether dihydric alcohol are 1000-3000, the polyester unit endows the polyurethane molecular chain with rigidity, the polyether unit endows the polyurethane molecular chain with flexibility, and the polyester and polyether dihydric alcohol both belong to soft segment parts; in the microstructure, the soft segment forms the continuous phase of the polyurethane, and plays a role in dispersing stress, so that the material has a certain buffering function and is macroscopically elastic.

Further preferably, the molar ratio of the total hydroxyl groups of the polyester diol and the polyether diol to the isocyanate groups in the isophorone diisocyanate is 1: 1.1-2.0.

Further preferably, the polyester diol is Polycaprolactone (PCL) diol, and the molecular weight is 1000-3000.

Further preferably, the polyether diol is polyethylene glycol ether (PEG) diol or polytetrahydrofuran ether (PTMG) diol, and the molecular weight is 1000-3000.

More preferably, the catalyst is dibutyltin dilaurate.

More preferably, the diisocyanate is isophorone diisocyanate.

The isocyanate is isophorone diisocyanate, and the two isocyanate groups of the isocyanate have different activities and are easy to form a polymer. Isocyanate and hydroxyl react to generate a urethane group unit, and the unit is used as a hard segment in a polyurethane molecule and can form a microcrystalline structure when aggregated to play a role in bearing stress; when the material is subjected to external force, the continuous phase formed by the soft sections transmits external pressure, so that stress is dispersed, and good elasticity of the material is ensured.

More preferably, the chain extender is at least one selected from 2, 2-dimethylolpropionic acid and trimethylolpropane; and further preferably, the chain extender is composed of a chain extender A and a chain extender B, wherein the chain extender A is 2, 2-dimethylolpropionic acid, the chain extender B is trimethylolpropane, the chain extender A is firstly added and the chain extender B is added later when the system reacts.

The aqueous chain extender A is 2, 2-dimethylolpropionic acid, and the main function of the chain extender is to increase the molecular weight so that the chain extender has preset mechanical properties; the carboxylic acid group on the 2, 2-dimethylolpropionic acid chain extender reacts with a neutralizer to generate anions with stronger hydrophilicity, so that the waterborne polyurethane material can be uniformly dispersed in water.

The aqueous chain extender B is trimethylolpropane, so that the adhesive force of aqueous polyurethane and a nonpolar material can be improved, the elastic modulus of the polyurethane is reduced, and the elongation at break and the viscoelasticity of the polyurethane are improved.

According to another technical scheme, the method for preparing the closed waterborne polyurethane comprises the following steps:

s1, heating polyester diol or/and polyether diol which are dried under reduced pressure to 60-90 ℃ in a nitrogen atmosphere, and simultaneously adding a small amount of catalyst for reaction for 20-40 min;

s2, adjusting the temperature to 40-60 ℃, adding an acetone solution of a water-based chain extender A for reacting for 180-300 min, and adding an acetone solution of a chain extender B for reacting for 30-60 min;

s3, adjusting the temperature to 30-50 ℃, adding a sealing agent, and reacting for 30-60 min until the content of isocyanate groups is zero;

s4, adding acetone for dilution at a constant temperature, and then adding triethylamine for reacting for 30-60 min;

s5, adjusting the temperature to room temperature, and adding pure water for dispersion;

s6, removing the acetone by reduced pressure rotary evaporation at room temperature.

Further preferably, the reaction temperature in the step S1 is 80 ℃ and the polymerization time is 30 min.

Further preferably, the reaction temperature of the aqueous chain extender A in the step S2 is 50 ℃, and the reaction time is 240 min; the reaction temperature of the aqueous chain extender B is 50 ℃, and the reaction time is 45 min.

Further preferably, the reaction temperature of the blocking agent in the step S3 is 40 ℃ and the reaction time is 45 min.

Further preferably, the reaction temperature in the step S4 is 40 ℃ and the reaction time is 30 min.

Further preferably, the pure water dispersion temperature in the S5 step is room temperature.

Further preferably, the rotary evaporation temperature in the step S5 is room temperature.

According to another technical scheme, the polyurethane/polyacrylate interpenetrating network structure polymer is obtained by deblocking the closed water-based polyurethane prepared by the method, and the deblocking temperature is 100-130 ℃ and the deblocking time is 10-30 min.

Further preferably, a small amount of ammonium persulfate is added into the closed waterborne polyurethane, the mixture is uniformly stirred, a film is coated, and the solution is unsealed at the temperature of 110 ℃ for 15min to obtain the polyurethane/polyacrylate interpenetrating network polymer.

By adopting the technical scheme, the prepared sealant can be subjected to a sealing reaction with isocyanate at 30-50 ℃, has high reaction rate and high sealing efficiency, and can be deblocked at a lower temperature (about 120 ℃); the preparation process of the closed waterborne polyurethane disclosed by the invention is green and environment-friendly, has no obvious peculiar smell, and has the characteristics of mild preparation conditions; the prepared closed waterborne polyurethane has excellent comprehensive performance, the deblocked sealing agent FEMA generates polyacrylate through free radical polymerization, and can form interpenetrating network structure polymer with complementary performance with polyurethane, and the obtained interpenetrating network structure polymer has the advantages of both the polyurethane and the polyacrylate based on the complementarity of the properties of the polyurethane and the polyacrylate, widens the application field of the closed waterborne polyurethane, and can be applied to industries such as light textile, leather processing, coating, wood processing, building materials, papermaking, adhesives and the like.

Detailed Description

The following further describes the embodiments of the present invention. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Reagents, methods and apparatus used in the present invention are conventional in the art and, unless otherwise specified, reagents and materials used in the following examples are commercially available.