CN108659689A - A kind of sorb alcohol radical non-isocyanate polyurethane coating and preparation method thereof - Google Patents

Abstract

The invention discloses a sorbitol-based non-isocyanate polyurethane coating and a preparation method thereof; in the preparation method, a sorbitol-based epoxy resin is added into a high-pressure reaction kettle, a catalyst is added, and carbon dioxide is introduced to maintain a pressure of 1.0-4.0MPa. reaction, the reaction temperature is 60-150°C, and the reaction is 4-30h to obtain a sorbitol-based cyclocarbonate solution; the sorbitol-based cyclocarbonate is mixed with a diamine curing agent or a polyamine curing agent, a solvent and a defoaming agent at room temperature Stir evenly to form a sorbitol-based non-isocyanate polyurethane coating, spray, bake and solidify to form a film; the sorbitol-based cyclocarbonate prepared by the invention is a yellow transparent liquid, non-toxic, and has good biodegradability. The non-isocyanate polyurethane coating prepared by it has high hardness, excellent impact resistance and chemical resistance, and is expected to become a green and environmentally friendly coating with excellent performance instead of traditional polyurethane.

Description

A kind of sorbitol-based non-isocyanate polyurethane coating and preparation method thereof

technical field

The invention relates to non-isocyanate polyurethane, in particular to a sorbitan-based non-isocyanate polyurethane coating and a preparation method thereof. The coating formed by the coating has good physical and chemical resistance properties.

Background technique

Polyurethane (PU) is one of the most important polymer materials. Due to its superior performance, it is used to make plastics, foams, elastomers, leather, adhesives, sealants, coatings, etc. and used in Buildings, electronic products, aircraft, cruise ships, furniture and other fields. Traditional polyurethane preparation uses diisocyanate as one of the starting materials. Diisocyanate is synthesized by toxic phosgene method. At the same time, diisocyanate contains toxic -NCO functional groups. Diisocyanate cannot contain water when synthesizing PU, because Water and -NCO have side reactions that affect storage, safety, transportation, and increase costs. The main reason is that traditional PU is toxic and pollutes the environment. Therefore, it is urgent to develop an isocyanate-free and environmentally friendly polyurethane to replace the traditional PU.

Non-isocyanate polyurethane (NIPU) does not contain toxic -NCO, consumes a large amount of greenhouse gas CO ₂ , is an environmentally friendly material, and its application prospects are very broad. It is expected to replace the application of traditional PU in the fields of coatings, adhesives, foams and sealants.

Chinese invention patent application CN 102718964A discloses that polyether diol diglycidyl ether is used as a raw material to synthesize the corresponding two-membered ring carbonate, and then prepare non-isocyanate polyurethane. Chinese invention patent application CN102731779A prepares non-isocyanate polyurethane through epoxy resin. However, the raw materials for these patent applications are mainly petroleum resources, which are not conducive to the concept of sustainable development due to their limited storage and non-renewable resources. Therefore, it is necessary to vigorously develop renewable biomass resources as raw materials to prepare non-isocyanate polyurethane coatings to reduce dependence on petroleum resources.

Contents of the invention

The invention provides a non-petroleum renewable biomass resource as a raw material, which is environmentally friendly and has a high yield of sorbitol-based non-isocyanate polyurethane coating and a preparation method thereof, so as to reduce dependence on petroleum resources, and the prepared sorbitol Based non-isocyanate polyurethane coatings have superior physical properties, chemical resistance and thermal stability.

The invention uses renewable resource sorbitol-based epoxy resin as raw material, inserts carbon dioxide to prepare sorbitol-based cyclocarbonate through high-pressure method, and then cures with different amines to prepare a series of non-isocyanate polyurethane coatings.

Sorbitol epoxy resin is a commercially available raw material with an average functionality of 4, a mixture of mono-, di-, tri-, tetra-, penta- and hexa-functional sorbitol A mixture of alcohol epoxy compounds, the structural formulas of these six compounds are shown in Figure 3.

Taking the sorbitol cyclocarbonate of 4 functionalities as an example, the mechanism of the synthesis of sorbitol-based cyclocarbonate compound by sorbitol epoxy resin is as follows:

The object of the invention is achieved through the following technical solutions:

A kind of preparation method of sorbitol-based non-isocyanate polyurethane coating, comprises the steps:

1) Preparation of sorbitol-based cyclocarbonate: Add sorbitol-based epoxy resin into a high-pressure reactor, add a catalyst, and feed carbon dioxide to maintain a pressure of 1.0-4.0MPa for reaction. The reaction temperature is 60-150°C. React for 4-30h to get a sorbitol-based cyclocarbonate solution; the addition of the catalyst is 0.5%-3.0% of the mass of the sorbitol-based epoxy resin; the catalyst is tetrabutylammonium bromide, lithium chloride, One or more mixtures of lithium bromide and tetrabutylammonium chloride;

2) Preparation of sorbitol-based non-isocyanate polyurethane coating: stir sorbitol cyclic carbonate with diamine curing agent or polyamine curing agent, solvent and defoamer at room temperature to form a sorbitol-based non-isocyanate polyurethane coating. Spraying, baking and curing to form a film;

The diamine curing agent is ethylenediamine, butylenediamine, hexamethylenediamine, 1,8-octanediamine, decylenediamine, 1,12-dodecanediamine, isophoronediamine, One or more mixtures of p-phenylenediamine, polyethyleneimine and polyether diamine;

The polyamine curing agent is polyethyleneimine.

To further realize the purpose of the present invention, preferably, step 1) also includes adding a DMF solvent of 0-100% by mass of the sorbitol-based epoxy compound when adding the catalyst.

Preferably, the molar ratio of the primary amine NH ₂ of the diamine curing agent or polyamine curing agent to the carbonate of sorbitol-based cyclocarbonate is 0.9-1.2:1.

Preferably, the defoamer is one or more mixtures of BYK-R605, TEGO Airex 900 and TEGO Airex 962, and the added amount of the defoamer is 0.5-1% of the mass of raw materials in step 2) .

Preferably, the solvent is 1-ethyl-2-pyrrolidone (NEP), dimethylsulfoxide (DMSO), dimethylformamide (DMF), 1-methyl-2-pyrrolidone (NMP) and One or more kinds of acetonitrile are mixed; the addition amount of the solvent is 30-100% of the mass of sorbitol cyclocarbonate.

Preferably, the sorbitol epoxy resin is obtained by reacting hexavalent alcohols with epichlorohydrin, including monofunctionality, difunctionality, trifunctionality, tetrafunctionality, pentafunctionality and hexafunctionality sorbitol A mixture of epoxy compounds with an average epoxy functionality of 4.

Preferably, the temperature for baking and curing to form a film is 80-150°C.

Preferably, the sorbitol-based cyclocarbonate solution is a light yellow transparent viscous liquid with a storage stability of more than one year and a viscosity of 9-50 mPa·s.

A sorbitol-based non-isocyanate polyurethane coating prepared by the above-mentioned preparation method; the coating film formed by the sorbitol-based non-isocyanate polyurethane coating has a hardness of 3B-4H, an impact resistance of ≥ 50 cm, and an adhesion of grade 0; flexibility Through the diameter of 1mm, the gloss is greater than 88%.

The basic principle of the present invention: the reaction mechanism of sorbitol-based cyclocarbonate and amine: the first step is that the amine carries out nucleophilic attack on the sorbitol-based cyclocarbonate to form a tetrahedral intermediate, and the second amine molecule attacks the first stage again The generated tetrahedral intermediate loses a proton H ⁺ , due to the unstable breakage of the carbon-oxygen bond at this time, and because of the high electron cloud density of the nitrogen atom, the third stage oxygen negative ion quickly forms alcohol with H ⁺ , and the final product is Urethane NIPU with -OH. Cyclic carbonate and diamine produce non-isocyanate polyurethane coating at 60-150°C. The non-isocyanate coating film synthesized by the above-mentioned synthesized sorbitol-based cyclocarbonate and various amines has excellent adhesion, and better water resistance and chemical resistance than traditional polyurethane.

Compared with the prior art, the present invention has the following advantages:

(1) Renewable biomass resources are used as raw materials, which are degradable and do not require petrochemical resources. This route is green and environmentally friendly;

(2) The yield of the sorbitol cyclocarbonate prepared by the high-pressure method is high, close to 100%.

(3) According to the requirements of coating performance, different kinds of diamines and polyamines can be compounded to achieve the required performance;

(4) The sorbitol-based non-isocyanate polyurethane coating prepared by the present invention has superior physical properties, chemical resistance and thermal stability.

Description of drawings

Fig. 1 is the infrared spectrogram of embodiment 1 sorbitol-based epoxy resin and sorbitol-based cyclocarbonate.

Fig. 2 is the infrared spectrogram of embodiment 1 sorbitol-based cyclocarbonate and NIPU-1.

Fig. 3 is the structural formula of monofunctionality, difunctionality, trifunctionality, tetrafunctionality, pentafunctionality and hexafunctionality sorbitol epoxy compound contained in sorbitol epoxy resin.

Detailed ways

In order to better understand the present invention, the present invention will be further described below in conjunction with the accompanying drawings and examples, but the embodiments of the present invention are not limited thereto.

Relevant test method in the embodiment is as follows:

Coating performance according to GB/T 9754-2007, GB/T 6739-2006, GB/T 1730-2007, GB/T 1731-1993, GB/T20624.2-2006, GB/T 9286-1998 and GB/T 2893.1-2005 Test the gloss, pencil hardness, flexibility, impact resistance, adhesion and chemical resistance of the coating respectively. The pencil is a high-grade drawing pencil produced by Shanghai China Pencil No. 1 Factory. The instruments used are Tianjin Jingke Materials Test machine factory production.

Example 1

(1) Preparation of sorbitol-based cyclocarbonate compound: the sorbitol-based epoxy resin (from the sorbitol glycidyl ether of Anhui Xinyuan Chemical Co., Ltd., the product number is XY666, and the average functionality of the epoxy group is 4, pale yellow liquid) and tetrabutylammonium bromide (addition amount is sorbitol-based epoxy resin quality 0.5%) are added in the autoclave, feed carbon dioxide (pressure maintains at 1.0MPa) and react at 120 ℃ for 24h, cooling temperature The pressure was released to obtain the sorbitan cyclocarbonate compound.

The present invention implements sorbitol epoxy resin, sorbitol-based cyclocarbonate, sorbitol-based non-isocyanate polyurethane NIPU structure to test with Spectrum 2000 Fourier infrared spectrometer, and the test results are shown in Fig. 1 and Fig. 2;

Fig. 1 is the infrared spectrogram of embodiment 1 sorbitol-based epoxy resin and sorbitol-based cyclocarbonate. As can be seen from the infrared spectrum 1, the epoxy characteristic peak of the sorbitol epoxy resin of peak a completely disappears, and a very obvious cyclocarbonate characteristic peak appears in b, which illustrates that the sorbitol-based ring synthesized in this embodiment The conversion rate of carbonate is close to 100%. In the infrared spectrum, a is sorbitol-based epoxy resin, and b is sorbitol-based cyclocarbonate.

Fig. 2 is the infrared spectrogram of embodiment 1 sorbitol-based cyclocarbonate and NIPU-1. The cyclic carbonate characteristic peak of sorbitol cyclic carbonate in the infrared spectrum of Fig. 2 disappears completely, and the characteristic peak of carbamate appears, shows that sorbitol cyclic carbonate and dibasic amine are completely solidified to produce sorbitol-based non-isocyanate polyurethane . In the infrared spectrum, SC is a sorbitan-based cyclocarbonate.

(2) Preparation of sorbitol-based non-isocyanate polyurethane coating (NIPU-1): according to the formula in Table 1, the above-mentioned sorbitol-based cyclocarbonate, dimethylformamide (DMF), isophorone diamine curing agent , The antifoaming agent is sprayed after being stirred evenly at room temperature, and cured at 120°C for 6 hours.

formula:

Table 1

(3) The performance results of the coating film are compared with the two-component polyurethane coating prepared by Covestro Arcol Polyol 3553 polyester polyol (the curing agent is Duranate ^TM HDI produced by Asahi Kasei Co., Ltd.) and the coating film of Dow epoxy resin DER ^TM 331 The performance comparison is as follows:

Table 2

As can be seen from Table 2, the sorbitol-based non-isocyanate polyurethane coating of the present invention is compared with the two-component polyurethane coating, and the coating film performance of the present invention has better glossiness and hardness, and under the same condition of flexibility, more High hardness requirement; compared with epoxy resin DER ^TM 331, the present invention has better performance in terms of gloss, impact strength and adhesion. The present invention is superior to both in terms of adhesion and water resistance. On the other hand, the raw material of the coating is a biomass resource sorbitol, a renewable resource, which reduces the dependence on petrochemical resources, the method is simple, the operation safety is improved, and the production cost is reduced; with _CO2 as raw material, the consumption Greenhouse gas emission reduction, green environmental protection.

Example 2

(1) Preparation of sorbitol-based cyclocarbonate compound: the sorbitol-based epoxy resin (from the sorbitol glycidyl ether of Anhui Xinyuan Chemical Co., Ltd., the product number is XY666, and the average functionality of the epoxy group is 4, Pale yellow liquid), catalyst lithium chloride (addition amount is epoxy resin quality 1.0%) is added in the autoclave, feeds carbon dioxide and maintains at 1.5MPa and reacts at 130 ℃ for 24h, cools down and releases pressure, obtains pitol-based ring Carbonate.

(2) Preparation of non-isocyanate polyurethane coating (NIPU-2): the above-mentioned sorbitol-based cyclocarbonate, 1-ethyl-2-pyrrolidone (NEP) (the addition is 40% of the total mass of the coating) butylenediamine is cured The agent and defoamer are sprayed after being stirred evenly at room temperature, and cured at 130°C.

formula:

table 3

(3) The performance comparison results of the coating film are as follows:

Table 4

Example 3

(1) Preparation of sorbitol-based cyclocarbonate compound: the sorbitol-based epoxy resin (from the sorbitol glycidyl ether of Anhui Xinyuan Chemical Co., Ltd., the product number is XY666, and the average functionality of the epoxy group is 4, Pale yellow liquid), catalyst lithium bromide (addition amount is 1.5% of epoxy resin quality) is added in the autoclave, feeds carbon dioxide and maintains at 1.2MPa and reacts at 140 ℃ for 24h, cools down and releases pressure, obtains pitolyl cyclocarbonate .

(2) Preparation of non-isocyanate polyurethane coating (NIPU-3): the above-mentioned sorbitol-based cyclocarbonate, dimethyl sulfoxide (DMSO) (the addition amount is 55% of the total mass of the coating) butylenediamine curing agent and disinfectant The foaming agent is sprayed after being stirred evenly at room temperature, and cured at 130°C.

formula:

table 5

(3) The performance comparison results of the coating film are as follows:

Table 6

Example 4

(1) Preparation of sorbitol-based cyclocarbonate compound: the sorbitol-based epoxy resin (from the sorbitol glycidyl ether of Anhui Xinyuan Chemical Co., Ltd., the product number is XY666, and the average functionality of the epoxy group is 4, Pale yellow liquid), catalyst tetrabutylammonium chloride (addition amount is 2.0% of epoxy resin quality) is added in the autoclave, feeds carbon dioxide and maintains at 2.0MPa and reacts 36h at 120 ℃, cools down and releases pressure, obtains pear Alcohol-based cyclocarbonate.

(2) Preparation of non-isocyanate polyurethane coating (NIPU-4): the above-mentioned sorbitol-based cyclocarbonate, dimethylformamide (DMF) (addition amount is 55% of the total mass of the coating) diamine curing agent and disinfectant The foaming agent is sprayed after being stirred evenly at room temperature, and cured at 130°C.

formula:

Table 7

(3) The performance results of the coating film are as follows:

Table 8

Example 5

(1) Preparation of sorbitol-based cyclocarbonate compound: the sorbitol-based epoxy resin (from the sorbitol glycidyl ether of Anhui Xinyuan Chemical Co., Ltd., the product number is XY666, and the average functionality of the epoxy group is 4, Pale yellow liquid) and tetrabutylammonium bromide (addition amount is epoxy resin quality 1.5%) are added in the autoclave, pass into carbon dioxide and maintain at 3MPa and react at 120 ℃ for 18h, cool down and release pressure, obtain sorbitol base Cyclocarbonate compounds.

(2) Preparation of non-isocyanate polyurethane coating (NIPU-5): sorbitol-based cyclocarbonate, dimethylformamide (DMF) (addition amount is 50% of the total mass of the coating) and 1,12-alkanediamine The curing agent and defoaming agent are sprayed after being stirred evenly at room temperature, and cured at 110°C.

formula:

Table 9

(3) The performance results of the coating film are as follows:

Table 10

Example 6

(1) Preparation of sorbitol-based cyclocarbonate compound: the sorbitol-based epoxy resin (from the sorbitol glycidyl ether of Anhui Xinyuan Chemical Co., Ltd., the product number is XY666, and the average functionality of the epoxy group is 4, Pale yellow liquid) and tetrabutylammonium bromide (addition amount is epoxy resin quality 2.0%) are added in the autoclave, pass into carbon dioxide and maintain at 4MPa and react 35h at 100 ℃, cool down and release pressure, obtain sorbitol base Cyclocarbonate compounds.

(2) Preparation of non-isocyanate polyurethane coating (NIPU-6): the above-mentioned sorbitol-based cyclocarbonate, acetonitrile (addition amount is 50% of the total mass of the coating) and tetraethylenepentamine curing agent and defoamer at room temperature After stirring evenly, spray it and cure it at 110°C.

formula:

Table 11

(3) The performance results of the coating film are as follows:

Table 12

The above embodiments are only to illustrate the technical ideas of the present invention, and cannot limit the protection scope of the present invention with this. Any non-creative changes made on the basis of the technical solutions of the present invention according to the technical conception of the present invention, all fall within the scope of this invention. Within the protection scope of the invention, the protection scope of the present invention shall be determined by the claims.

Claims (9)

1. a preparation method of sorbitol-based non-isocyanate polyurethane coating, is characterized in that comprising the steps: 1) Preparation of sorbitol-based cyclocarbonate: Add sorbitol-based epoxy resin into a high-pressure reactor, add a catalyst, and feed carbon dioxide to maintain a pressure of 1.0-4.0MPa for reaction. The reaction temperature is 60-150°C. React for 4-30h to get a sorbitol-based cyclocarbonate solution; the addition of the catalyst is 0.5%-3.0% of the mass of the sorbitol-based epoxy resin; the catalyst is tetrabutylammonium bromide, lithium chloride, One or more mixtures of lithium bromide and tetrabutylammonium chloride; 2) Preparation of sorbitol-based non-isocyanate polyurethane coating: stir sorbitol cyclic carbonate with diamine curing agent or polyamine curing agent, solvent and defoamer at room temperature to form a sorbitol-based non-isocyanate polyurethane coating. Spraying, baking and curing to form a film; The diamine curing agent is ethylenediamine, butylenediamine, hexamethylenediamine, 1,8-octanediamine, decylenediamine, 1,12-dodecanediamine, isophoronediamine, One or more mixtures of p-phenylenediamine, polyethyleneimine and polyetherdiamine; The polyamine curing agent is polyethyleneimine. 2. according to the preparation method of the described sorbitol base non-isocyanate polyurethane coating of claim 1, it is characterized in that, step 1) also comprises adding the DMF solvent of sorbitol base epoxy compound quality 0-100% when adding catalyst. 3. according to the preparation method of the described sorbitol base non-isocyanate polyurethane coating of claim 1, it is characterized in that, the primary amine NH of described diamine curing agent or polyamine curing agent ₂ and the carbonic acid of sorbitol base cyclocarbonate The molar ratio of esters is 0.9-1.2:1. 4. according to the preparation method of the described sorbitol base non-isocyanate polyurethane coating of claim 1, it is characterized in that, described defoamer is one or more mixtures in BYK-R605, TEGO Airex 900 and TEGO Airex 962 , the added amount of the defoamer is 0.5-1% of the mass of raw materials in step 2). 5. according to the preparation method of the described sorbitol base non-isocyanate polyurethane coating of claim 1, it is characterized in that, described solvent is 1-ethyl-2-pyrrolidone, dimethylsulfoxide, dimethylformamide, 1 One or more of methyl-2-pyrrolidone and acetonitrile are mixed; the addition amount of the solvent is 30-100% of the mass of sorbitol cyclocarbonate. 6. according to the preparation method of the described sorbitol base non-isocyanate polyurethane coating of claim 1, it is characterized in that, described sorbitol epoxy resin is gained by reaction of hexavalent alcohol and epichlorohydrin, contains one functionality, two A mixture of functional, trifunctional, tetrafunctional, pentafunctional and hexafunctional sorbitol-based epoxy compounds with an average epoxy group functionality of 4. 7. The method for preparing the sorbitol-based non-isocyanate polyurethane coating according to claim 1, characterized in that, the temperature of said baking and curing film forming is 80-150°C. 8. according to the preparation method of the described sorbitol-based non-isocyanate polyurethane coating of claim 1, it is characterized in that, described sorbitol-based cyclocarbonate solution is light yellow transparent viscous liquid, storage stability is greater than 1 year, and viscosity is 9-50mPa·s. 9. A sorbitol-based non-isocyanate polyurethane coating is characterized in that it is made by the preparation method described in any one of claims 1-8; the coating film hardness formed by the sorbitol-based non-isocyanate polyurethane coating is 3B- 4H, impact resistance ≥ 50cm, adhesion level 0; flexibility through diameter 1mm, glossiness greater than 88%.