阅读说明：本技术 一种hdi-tdi混合多聚体固化剂及其制备方法 (HDI-TDI mixed polymer curing agent and preparation method thereof ) 是由 黄洪 陆洁锋 司徒粤 于 2021-07-01 设计创作，主要内容包括：本发明公开了一种HDI-TDI混合多聚体固化剂及其制备方法。本发明的HDI-TDI混合多聚体固化剂由HDI三聚体、甲苯二异氰酸酯、催化剂、抗氧化剂和阻聚剂制成,其制备方法包括以下步骤：1)将HDI三聚体和抗氧化剂加入反应釜,充入保护气,进行搅拌；2)将甲苯二异氰酸酯加入反应釜,进行搅拌；3)将催化剂加入反应釜,搅拌至反应混合物中NCO含量为19％±1％；4)将阻聚剂加入反应釜,进行搅拌,即得HDI-TDI混合多聚体固化剂。本发明的HDI-TDI混合多聚体固化剂具有游离TDI单体含量极低、二甲苯容忍度高、粘度较低的特点,且制备工艺简单、生产成本低,适合进行大规模工业化生产。(The invention discloses an HDI-TDI mixed polymer curing agent and a preparation method thereof. The HDI-TDI mixed polymer curing agent is prepared from HDI tripolymer, toluene diisocyanate, catalyst, antioxidant and polymerization inhibitor, and the preparation method comprises the following steps: 1) adding HDI tripolymer and antioxidant into a reaction kettle, filling protective gas, and stirring; 2) adding toluene diisocyanate into a reaction kettle, and stirring; 3) adding a catalyst into a reaction kettle, and stirring until the NCO content in the reaction mixture is 19% +/-1%; 4) adding a polymerization inhibitor into the reaction kettle, and stirring to obtain the HDI-TDI mixed polymer curing agent. The HDI-TDI mixed polymer curing agent has the characteristics of extremely low free TDI monomer content, high xylene tolerance and lower viscosity, and is simple in preparation process, low in production cost and suitable for large-scale industrial production.)

1. An HDI-TDI mixed polymer curing agent is characterized by being prepared from the following raw materials in parts by mass:

HDI trimer: 90-95 parts;

toluene diisocyanate: 3-8 parts;

catalyst: 0.1 to 0.9 portion;

antioxidant: 0.02 to 0.2 portion;

polymerization inhibitor: 0.11 to 0.99 portion.

2. An HDI-TDI mixed polymer curing agent according to claim 1, characterized in that: the catalyst is prepared by compounding a tertiary amine catalyst and an organic metal catalyst according to the mass ratio of 1: 0.1-1: 5.

3. An HDI-TDI mixed polymer curing agent according to claim 2, characterized in that: the tertiary amine catalyst is at least one of 2,4, 6-tri (dimethylaminomethyl) phenol and Mannich base catalyst.

4. An HDI-TDI mixed polymer curing agent according to claim 2, characterized in that: the organic metal catalyst is at least one of calcium acetate, potassium isooctanoate and zinc isooctanoate.

5. An HDI-TDI mixed polymer curing agent according to any one of claims 1 to 4, wherein: the antioxidant is at least two of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, tri (2, 4-di-tert-butylphenyl) phosphite and dibutyl hydroxy toluene.

6. An HDI-TDI mixed polymer curing agent according to any one of claims 1 to 4, wherein: the polymerization inhibitor is at least one of benzoyl chloride, phosphoric acid and methyl p-toluenesulfonate.

7. The method for preparing the HDI-TDI mixed polymer curing agent as recited in any one of claims 1 to 6, comprising the steps of:

1) adding HDI tripolymer and antioxidant into a reaction kettle, filling protective gas, and stirring;

2) adding toluene diisocyanate into a reaction kettle, and stirring;

3) adding a catalyst into a reaction kettle, and stirring until the NCO content in the reaction mixture is 19% +/-1%;

4) adding a polymerization inhibitor into the reaction kettle, and stirring to obtain the HDI-TDI mixed polymer curing agent.

8. The method for preparing an HDI-TDI mixed polymer curing agent according to claim 7, wherein: the stirring in the step 1) is carried out at the temperature of 20-80 ℃, and the stirring time is 5-10 min.

9. The method for preparing an HDI-TDI mixed polymer curing agent according to claim 7 or 8, wherein: the stirring in the step 2) is carried out at the temperature of 20-80 ℃, and the stirring time is 30-60 min.

10. The method for preparing an HDI-TDI mixed polymer curing agent according to claim 7 or 8, wherein: the stirring in the step 3) is carried out at the temperature of 20-80 ℃, and the stirring time is 4-8 h; and 4) stirring at 20-80 ℃ for 40-80 min.

Technical Field

The invention relates to the technical field of polyurethane curing agents, in particular to an HDI-TDI mixed polymer curing agent and a preparation method thereof.

Background

Two-component polyurethane coatings occupy a very important position in polyurethane coating systems, one of their main components being polyisocyanates, including HDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate) and TDI (toluene diisocyanate) and their derivatives. The polyurethane coating prepared by the HDI tripolymer curing agent has excellent weather resistance, heat resistance, gloss retention and color retention, and is widely applied to open buildings such as bridges, towers and tanks, and the coating of automobiles, indoor and outdoor decorations, machine tools, ships and spacecrafts. Compared with HDI derivative curing agents, the TDI derivative curing agent has lower cost, the hardness of a coating film after paint preparation is higher, but the coating film is easier to oxidize and yellow, and the HDI-TDI mixed polymer curing agent can combine the advantages of the TDI derivative curing agent and the HDI derivative curing agent to a certain extent.

The HDI monomer and the TDI monomer are easy to volatilize at normal temperature, and the free HDI monomer and the TDI monomer which exceed the standard can cause harm to human bodies, mainly have strong stimulation to respiratory tracts, eyes, mucous membranes and skins of people, and even cause chemical pneumonia, pulmonary edema and the like seriously. The national standard GB 18581-.

Therefore, a method for preparing an HDI-TDI mixed polymer curing agent with simple development process and low production cost is needed, and the HDI-TDI mixed polymer curing agent with low free HDI and TDI monomer content is prepared.

Disclosure of Invention

The invention aims to provide an HDI-TDI mixed polymer curing agent and a preparation method thereof.

The technical scheme adopted by the invention is as follows:

an HDI-TDI mixed polymer curing agent is prepared from the following raw materials in parts by mass:

HDI trimer: 90-95 parts;

toluene diisocyanate: 3-8 parts;

catalyst: 0.1 to 0.9 portion;

antioxidant: 0.02 to 0.2 portion;

polymerization inhibitor: 0.11 to 0.99 portion.

Preferably, the mass ratio of the HDI trimer to the toluene diisocyanate is 11.5: 1-19: 1.

Preferably, the HDI trimer is BayerN 3390。

Preferably, the catalyst is prepared by compounding a tertiary amine catalyst and an organic metal catalyst according to the mass ratio of 1: 0.1-1: 5. The tertiary amine catalyst has weak catalytic effect in the later reaction stage, and the tertiary amine catalyst and the organic metal catalyst are compounded for use, so that the reaction process can be accelerated, the product viscosity can be effectively reduced, and the content of free monomers in the product can be reduced.

More preferably, the catalyst is prepared by compounding a tertiary amine catalyst and an organic metal catalyst according to the mass ratio of 1: 1.

Preferably, the tertiary amine catalyst is at least one of 2,4, 6-tris (dimethylaminomethyl) phenol and a mannich base catalyst.

Preferably, the mannich base is prepared by the following method: adding bisphenol A and dimethylamine aqueous solution into a reaction kettle, stirring for 10-30 min at 60-90 ℃, then dropwise adding formaldehyde aqueous solution, continuing to react for 5-6 h after dropwise adding, standing for layering, taking a lower organic layer for reduced pressure distillation, and dispersing a product in a solvent to obtain the Mannich base catalyst (marked as MNBA).

Preferably, the organometallic catalyst is at least one of calcium acetate, potassium isooctanoate, and zinc isooctanoate.

Preferably, the antioxidant is at least two of pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], tris (2, 4-di-tert-butylphenyl) phosphite and dibutylhydroxytoluene.

Preferably, the polymerization inhibitor is at least one of benzoyl chloride, phosphoric acid and methyl p-methyl benzenesulfonate.

The preparation method of the HDI-TDI mixed polymer curing agent comprises the following steps:

1) adding HDI tripolymer and antioxidant into a reaction kettle, filling protective gas, and stirring;

2) adding toluene diisocyanate into a reaction kettle, and stirring;

3) adding a catalyst into a reaction kettle, and stirring until the NCO content in the reaction mixture is 19% +/-1%;

4) adding a polymerization inhibitor into the reaction kettle, and stirring to obtain the HDI-TDI mixed polymer curing agent.

Preferably, the protective gas in step 1) is one of nitrogen and argon.

Preferably, the stirring in the step 1) is carried out at 20-80 ℃, and the stirring time is 5-10 min.

Preferably, the stirring in the step 2) is carried out at 20-80 ℃, and the stirring time is 30-60 min.

Preferably, the stirring in the step 3) is carried out at the temperature of 20-80 ℃, and the stirring time is 4-8 h.

Preferably, the stirring in the step 4) is carried out at 20-80 ℃, and the stirring time is 40-80 min.

The invention has the beneficial effects that: the HDI-TDI mixed polymer curing agent has the characteristics of extremely low free TDI monomer content, high xylene tolerance and lower viscosity, and is simple in preparation process, low in production cost and suitable for large-scale industrial production.

Specifically, the method comprises the following steps:

1) according to the invention, the HDI-TDI mixed polymer is synthesized by adopting a mode of doping HDI tripolymer into a small amount of TDI monomer for copolymerization, so that the TDI monomer can be ensured to completely participate in reaction as far as possible, and the HDI-TDI mixed polymer curing agent with extremely low free TDI monomer content is finally obtained (the reaction activity of the TDI monomer is far higher than that of the HDI monomer, if the monomer is adopted for polymerization, most of the TDI monomer can be polymerized, the amount of the HDI monomer participating in reaction is less, a large amount of HDI monomer can be remained finally, a thin film evaporation method is adopted for monomer separation, and the production cost and the operation difficulty can be greatly increased);

2) the HDI-TDI mixed polymer curing agent has the following indexes: the NCO content is 19.5% +/-1%, the solid content is 90.5% +/-1%, the free TDI is less than or equal to 0.3%, the tolerance of dimethylbenzene is more than or equal to 3.0, and the viscosity value is 1000cp +/-500 cp.

Detailed Description

The invention will be further explained and illustrated with reference to specific examples.

Example 1:

an HDI-TDI mixed polymer curing agent, which is prepared by the following steps:

1) 0.06g of dehydrated tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite (tetrakis- [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1) were charged into a reaction vessel having a volume of 250mL, nitrogen was introduced, and 95g of HDI trimer was addedAdding N3390 into the reaction kettle, and stirring for 10min at 50 ℃;

2) adding 5g of toluene diisocyanate into a reaction kettle, and stirring for 60min at 50 ℃;

3) 0.1g of 2,4, 6-tris (dimethylaminomethyl) phenol and 0.1g of zinc isooctanoate are added into a reaction kettle dropwise and stirred at 50 ℃ until the NCO content in the reaction mixture is 19.5% +/-0.5%;

4) adding 0.22g of benzoyl chloride into the reaction kettle, stirring for 60min at 50 ℃, cooling and discharging to obtain the HDI-TDI mixed polymer curing agent.

And (3) performance testing:

the physical and chemical indexes of the HDI-TDI mixed polymer curing agent of example 1 are shown in the following table:

TABLE 1 physicochemical indices of HDI-TDI mixed polymer curing agent of example 1

Note:

NCO content: the content of isocyanic acid radical in polymethylene polyphenyl isocyanate is tested by adopting a di-n-butylamine titration method according to a GB/T12009.4-1989 measuring method;

solid content: the test was carried out with reference to "determination of the nonvolatile content of adhesive in GB/T2793-;

tolerance to xylene: dissolving a product with a certain mass in xylene, testing the mass of the xylene when the product starts to emit blue light and a solution generates a trace amount of white substances, and converting the mass ratio into a molar ratio, namely the tolerance;

viscosity: the test is carried out at 25 ℃ by using a rotary viscometer according to the single-cylinder rotary viscometer method for measuring the viscosity of GB/T2794-2013 adhesive;

HDI, TDI free value: the test was carried out using gas chromatography with reference to "determination of diisocyanate monomers in binder isocyanate resins for GB/T18446-.

Example 2:

an HDI-TDI mixed polymer curing agent, which is prepared by the following steps:

1) 0.06g of dehydrated tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite (tetrakis- [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1) were charged into a reaction vessel having a volume of 250mL, nitrogen was introduced, and 95g of HDI trimer was addedAdding N3390 into the reaction kettle, and stirring for 10min at 50 ℃;

2) adding 5g of toluene diisocyanate into a reaction kettle, and stirring for 60min at 50 ℃;

3) dropwise adding 0.1g of 2,4, 6-tris (dimethylaminomethyl) phenol and 0.1g of stannous octoate into a reaction kettle, and stirring at 50 ℃ until the NCO content in the reaction mixture is 19.5% +/-0.5%;

4) adding 0.22g of benzoyl chloride into the reaction kettle, stirring for 60min at 50 ℃, cooling and discharging to obtain the HDI-TDI mixed polymer curing agent.

And (3) performance testing:

the physical and chemical indexes of the HDI-TDI mixed polymer curing agent of example 2 are shown in the following table:

TABLE 2 physicochemical indices of HDI-TDI mixed polymer curing agent of example 2

Example 3:

an HDI-TDI mixed polymer curing agent, which is prepared by the following steps:

1) 0.06g of dehydrated tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite (tetrakis- [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1) were charged into a reaction vessel having a volume of 250mL, nitrogen was introduced, and 95g of HDI trimer was addedAdding N3390 into the reaction kettle, and stirring for 10min at 50 ℃;

2) adding 5g of toluene diisocyanate into a reaction kettle, and stirring for 60min at 50 ℃;

3) 0.1g of MNBA and 0.1g of zinc isooctanoate are dripped into a reaction kettle and stirred at 50 ℃ until the NCO content in the reaction mixture is 19.5% +/-0.5%;

4) adding 0.22g of benzoyl chloride into the reaction kettle, stirring for 60min at 50 ℃, cooling and discharging to obtain the HDI-TDI mixed polymer curing agent.

And (3) performance testing:

the physical and chemical indexes of the HDI-TDI mixed polymer curing agent of example 3 are shown in the following table:

TABLE 3 physicochemical indices of HDI-TDI mixed polymer curing agent of example 3

Note:

the MNBA is prepared by the following method: adding 25g of bisphenol A and 55.2g of 35 wt% dimethylamine aqueous solution into a reaction kettle, stirring for 20min at 60 ℃, dropwise adding 32.2g of 40 wt% formaldehyde aqueous solution within 30min, continuing to react for 5h after dropwise adding, standing for layering, taking a lower organic layer for reduced pressure distillation, and dispersing a product in n-butyl acetate while hot to prepare a 30 wt% solution to obtain the Mannich base catalyst (marked as MNBA).

Comparative example 1:

an HDI-TDI mixed polymer curing agent, which is prepared by the following steps:

1) 0.06g of dehydrated tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite (tetrakis- [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1) were charged into a reaction vessel having a volume of 250mL, nitrogen was introduced, and 95g of HDI trimer was addedAdding N3390 into the reaction kettle, and stirring for 10min at 50 ℃;

2) adding 5g of toluene diisocyanate into a reaction kettle, and stirring for 60min at 50 ℃;

3) 0.2g of 2,4, 6-tris (dimethylaminomethyl) phenol is dripped into a reaction kettle and stirred at 50 ℃ until the NCO content in the reaction mixture is 19.5% +/-0.5%;

4) adding 0.22g of benzoyl chloride into the reaction kettle, stirring for 60min at 50 ℃, cooling and discharging to obtain the HDI-TDI mixed polymer curing agent.

And (3) performance testing:

physicochemical indices of the HDI-TDI mixed polymer curing agent of comparative example 1 are shown in the following table:

TABLE 4 physicochemical indices of the HDI-TDI mixed polymer curing agent of comparative example 1

Comparative example 2:

an HDI-TDI mixed polymer curing agent, which is prepared by the following steps:

1) 0.06g of dehydrated tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite (. beta. - (3, 5-di-tert-butyl)4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1) were charged into a reaction vessel having a volume of 250mL, nitrogen was introduced, and 95g of HDI trimer was addedAdding N3390 into the reaction kettle, and stirring for 10min at 50 ℃;

2) adding 5g of toluene diisocyanate into a reaction kettle, and stirring for 60min at 50 ℃;

3) dropwise adding 0.2g of zinc isooctanoate into a reaction kettle, and stirring at 50 ℃ until the NCO content in the reaction mixture is 19.5% +/-0.5%;

4) adding 0.22g of benzoyl chloride into the reaction kettle, stirring for 60min at 50 ℃, cooling and discharging to obtain the HDI-TDI mixed polymer curing agent.

And (3) performance testing:

physicochemical indices of the HDI-TDI mixed polymer curing agent of comparative example 2 are shown in the following table:

TABLE 5 physicochemical indices of the HDI-TDI mixed polymer curing agent of comparative example 2

Comparative example 3:

an HDI-TDI mixed polymer curing agent, which is prepared by the following steps:

1) 0.06g of dehydrated tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite (tetrakis- [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid]Pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1) were charged into a reaction vessel having a volume of 250mL, nitrogen was introduced, and 95g of HDI trimer was addedN3390 addition reactionStirring the mixture in a kettle at 50 ℃ for 10 min;

2) adding 5g of toluene diisocyanate into a reaction kettle, and stirring for 60min at 50 ℃;

3) 0.2g of MNBA (the preparation method is the same as that of example 3) is dripped into the reaction kettle and stirred at 50 ℃ until the NCO content in the reaction mixture is 19.5% +/-0.5%;

4) adding 0.22g of benzoyl chloride into the reaction kettle, stirring for 60min at 50 ℃, cooling and discharging to obtain the HDI-TDI mixed polymer curing agent.

And (3) performance testing:

physicochemical indices of the HDI-TDI mixed polymer curing agent of comparative example 3 are shown in the following table:

TABLE 6 physicochemical indices of the HDI-TDI mixed polymer curing agent of comparative example 3

Comparative example 4:

an HDI-TDI mixed polymer curing agent, which is prepared by the following steps:

1) adding 0.06g of dehydrated pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris (2, 4-di-tert-butylphenyl) phosphite (pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate) and tris (2, 4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1) into a reaction kettle with a volume of 250mL, introducing nitrogen, adding 95g of HDI monomer into the reaction kettle, and stirring at 50 ℃ for 10 min;

2) adding 5g of toluene diisocyanate into a reaction kettle, and stirring for 60min at 50 ℃;

3) 0.1g of MNBA (the preparation method is the same as that of the example 3) and 0.1g of zinc isooctanoate are dripped into a reaction kettle, stirring is carried out at the temperature of 50 ℃, and NCO content detection is carried out once per hour until the NCO content is basically unchanged;

4) adding 0.22g of benzoyl chloride into the reaction kettle, stirring for 60min at 50 ℃, cooling and discharging to obtain the HDI-TDI mixed polymer curing agent.

And (3) performance testing:

the HDI-TDI mixed polymer curing agent obtained in the comparative example was in the form of a water-white transparent liquid, the NCO content was 39.61%, the free values of HDI and TDI were 59.21%, and the free monomers had to be removed by thin film evaporation.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.