Flame-retardant polyurethane regenerated polyol as well as preparation method and application thereof

Abstract

The invention discloses flame-retardant polyurethane regenerated polyol as well as a preparation method and application thereof, and belongs to the field of regenerated polyol. The preparation method comprises the following steps: (1) cleaning, crushing and drying rigid polyurethane foam plastic waste to prepare recycled rigid polyurethane foam particles; (2) carrying out degradation reaction on the recycled rigid polyurethane foam particles, a compound alcoholysis agent consisting of dihydric alcohol and melamine polyol and a catalyst in a protective atmosphere to obtain an intermediate product; and (3) cooling the intermediate product, carrying out reduced pressure distillation, and filtering to obtain the flame-retardant polyurethane regenerated polyol. In the compound alcoholysis agent, the melamine polyol with flame retardant property participates in alcoholysis reaction, so that the prepared polyurethane regenerated polyol has excellent flame retardant property, and the rigid polyurethane foam prepared from the polyurethane regenerated polyol has more excellent compression strength and dimensional stability; the process is simple and easy to operate, and resource waste can be reduced.

Description

Technical Field

[0001] The invention belongs to the field of regenerated polyols, and in particular relates to a flame retardant polyurethane regenerated polyol and a preparation method and application thereof. Background Art

[0002] At present, the global polyurethane industry is developing rapidly, increasing rapidly every year. By the end of 2016, the scale of China's polyurethane industry reached 1.056×10 10 The amount of polyurethane waste is increasing, which seriously pollutes the environment. The recycling of waste polyurethane products is becoming more and more important. The recycling of waste polyurethane foam is a green and environmentally friendly project. The development of a circular economy recycling method has become a hot topic in the industry.

[0003] However, although polyurethane foam has many excellent properties, polyurethane foam without flame retardant modification is flammable. After burning, it will decompose and produce a large amount of toxic gas smoke such as NO, NO2, HCN, etc. In particular, many fire accident cases in recent years have attracted people's attention to flame retardant polyurethane. At the same time, many countries have promulgated relevant laws and regulations, clearly stipulating that in certain occasions, polyurethane materials must meet certain flame retardant standards. Therefore, it is urgent to study flame retardant polyurethane.

[0004] At present, the waste polyurethane recycling industry is gradually emerging. Research on polyurethane foam with flame retardant properties has just emerged in recent years, and there are many related reports, but all of them add flame retardants to the foaming formula to achieve the purpose of flame retardancy. In addition, most polyurethane chemical recycling processes use alcoholysis, and the alcoholysis agent used is a small molecule polyol with two functionalities. The functionality of the prepared recycled polyol is low, which leads to poor compression strength and dimensional stability of the polyurethane rigid foam prepared from the recycled polyol.

[0005] For example, the Chinese patent with application number 202110771867.7 discloses a halogen-free flame-retardant foam material and its preparation method and application. The preparation method comprises the following steps: mixing waste polyurethane, alcoholysis agent, alcoholysis aid, phosphorus flame retardant and graphene oxide, performing degradation reaction, and obtaining degradable polyol, wherein the phosphorus flame retardant is one or more of dihydroxy DOPO reactive flame retardant and dicarboxyl DOPO reactive flame retardant; mixing component A and isocyanate compound for foaming, and obtaining the halogen-free flame-retardant foam material, wherein component A comprises the degradable polyol, chain extender, foaming agent, catalyst and stabilizer. This patent prepares flame-retardant foam material based on alcoholysis and adding flame retardant. However, the phosphorus flame retardant used in this method is solid powder, which is easy to settle, and is relatively expensive, making industrialization difficult. Summary of the invention

[0006] Purpose of the invention: The present invention aims to provide a flame retardant polyurethane recycled polyol having excellent application performance and a simple and environmentally friendly preparation method. The second purpose of the present invention is to provide a preparation method of the above-mentioned flame retardant polyurethane recycled polyol. The third purpose of the present invention is to provide the application of the above-mentioned flame retardant polyurethane recycled polyol.

[0007] Technical solution: The method for preparing the flame-retardant polyurethane regenerated polyol of the present invention comprises the following steps:

[0008] (1) washing, crushing and drying the polyurethane rigid foam plastic waste to obtain recycled polyurethane rigid foam particles;

[0009] (2) subjecting the recovered polyurethane rigid foam particles, a composite alcoholysis agent composed of a diol and a melamine polyol, and a catalyst to a degradation reaction under a protective atmosphere to obtain an intermediate product;

[0010] (3) Cooling the intermediate product, performing vacuum distillation, and filtering to obtain flame-retardant polyurethane regenerated polyol.

[0011] Furthermore, in step (2), the mass ratio of the recovered polyurethane rigid foam particles to the compound alcoholysis agent is 1:1-1.25, preferably 1:1; in the compound alcoholysis agent, the mass ratio of the diol to the melamine polyol is 1:4-4, and the mass ratio of the recovered polyurethane rigid foam particles to the catalyst is 500:5-8.

[0012] Furthermore, in step (2), the diol is at least one of ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; the melamine polyol is at least one of EDS-5083L, EDS-5083H, and CN-3360; and the catalyst is at least one of potassium hydroxide, sodium hydroxide, triethylenediamine, and dibutyltin dilaurate.

[0013] Furthermore, in step (3), the conditions of the degradation reaction are: under nitrogen atmosphere, the reaction time is 3-6h, preferably 3-5h, and the reaction temperature is 170-200°C, preferably 170-195°C.

[0014] Furthermore, the cooling temperature is 100-120°C; the pressure of the vacuum distillation is -0.09MPa to -0.098MPa, and the temperature of the vacuum distillation is 110-120°C.

[0015] The flame retardant polyurethane regenerated polyol is prepared by the preparation method.

[0016] The flame retardant polyurethane recycled polyol is used in the preparation of polyurethane rigid foam plastics.

[0017] Principle of the invention: The present invention adopts melamine polyol with flame retardant properties as an alcoholysis agent to participate in the alcoholysis reaction, so that the regenerated polyol itself has excellent flame retardant properties, and the prepared polyurethane rigid foam has better compression strength and dimensional stability.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: (1) Using polyurethane rigid foam waste as raw material, melamine polyol with excellent flame retardancy and dimensional stability is selected and matched with diol as alcoholysis agent to prepare regenerated polyol with flame retardancy, and the dimensional stability of the polyurethane rigid foam prepared in this way is also relatively excellent; (2) The alcoholysis agent and catalyst used in the production process do not affect the reuse of the regenerated polyol, and it can be directly used without going through complicated purification steps; (3) The hydroxyl value of the regenerated polyol is between 545-594 mgKOH / g, and the acid value is between 0.54-0.89 mgKOH / g, which meets the requirements of polyol for rigid foam, and the hydroxyl value can be adjusted by adjusting the ratio of alcoholysis agent to polyurethane rigid foam particles to meet different needs. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the embodiments.

[0020] The relevant information of the raw materials used in the implementation method is shown in Table 1 below.

[0021] Table 1 List of raw materials

[0022]

[0023] Example 1: The steps of preparing the flame-retardant polyurethane regenerated polyol provided in this example are as follows:

[0024] (1) washing, crushing and drying the polyurethane rigid foam waste recovered from the semi-rigid foam of the polyurethane automobile roof to obtain recycled polyurethane rigid foam particles;

[0025] (2) Add the recycled polyurethane rigid foam particles, diethylene glycol, melamine polyol EDS-5083L, and potassium hydroxide in a mass ratio of 50:40:10:0.5 into a reaction bottle, mix and react for 5 hours under a nitrogen atmosphere at a reaction temperature of 170°C;

[0026] (3) Cooling to 120° C., removing small molecules such as water by vacuum distillation, and filtering to obtain flame-retardant polyurethane regenerated polyol.

[0027] Examples 2 to 7 and Comparative Example 1 are carried out according to the steps in Example 1, except for the reaction raw materials, raw material ratio, reaction time, and reaction temperature. The relevant data are shown in Table 2; the performance data of the flame-retardant polyurethane recycled polyol obtained are shown in Table 4.

[0028] Table 2 Mass ratio of raw materials and reaction conditions in Example 1-Example 7 and Comparative Example 1

[0029]

[0030] Example 8-Example 14 and Comparative Example 2: The flame retardant regenerated polyols prepared in Example 1-Example 7 and Comparative Example 1 are added to the polyurethane rigid foaming formula respectively. The weight proportions of each component in the formula are shown in Table 3. The physical properties data of the prepared polyurethane rigid foam are shown in Table 5.

[0031] Table 3 Amount of each component added to the polyurethane rigid foam formula in Examples 1 to 7 and Comparative Example 1

[0032]

[0033] Table 4 Data of flame retardant polyurethane regenerated polyols prepared from Examples 1 to 7 and Comparative Example 1

[0034]

[0035] Table 5 Performance data of polyurethane rigid foam prepared by Examples 8 to 14 and Comparative Example 2

[0036]

[0037] It can be seen from the performance data of the polyurethane rigid foam in Table 5 that when the flame-retardant polyurethane recycled polyols prepared in Examples 1 to 7 and the recycled polyols prepared in Comparative Example 1 are added in the same amount to the same polyurethane rigid foam formula, the flame retardant properties and compressive strength of the polyurethane rigid foams prepared in Examples 8 to 14 are better than those of the polyurethane rigid foam plastics prepared in Comparative Example 2, the oxygen index is increased by more than 16.6%, the compressive strength in the parallel and vertical directions are increased by 13.6% and 4.5% respectively, and the dimensional stability of the foam plastic is also better. It can be seen that the flame-retardant polyurethane recycled polyols prepared based on the recovery of polyurethane rigid foam waste foams of the present invention can be recycled in polyurethane rigid foams, which can not only reduce resource waste and protect the environment, but also improve the flame retardant properties, compressive strength and dimensional stability of polyurethane rigid foam plastics.

Claims

1. A method for preparing a flame retardant polyurethane regenerated polyol, characterized in that: The following steps are involved: (1) washing, crushing and drying the polyurethane rigid foam plastic waste to obtain recycled polyurethane rigid foam particles; (2) subjecting the recovered polyurethane rigid foam particles, a composite alcoholysis agent composed of a diol and a melamine polyol, and a catalyst to a degradation reaction under a protective atmosphere to obtain an intermediate product; (3) Cooling the intermediate product, performing vacuum distillation, and filtering to obtain flame-retardant polyurethane regenerated polyol.

2. The method for preparing flame-retardant polyurethane regenerated polyol according to claim 1, characterized in that: In step (2), the mass ratio of the recovered polyurethane rigid foam particles to the compound alcoholysis agent is 1:1-1.

25.

3. The method for preparing flame-retardant polyurethane regenerated polyol according to claim 1, characterized in that: In step (2), in the composite alcoholysis agent, the mass ratio of diol to melamine polyol is 1:4-4.

4. The method for preparing flame-retardant polyurethane regenerated polyol according to claim 1, characterized in that: In step (2), the mass ratio of the recovered polyurethane rigid foam particles to the catalyst is 500:5-8.

5. The method for preparing flame-retardant polyurethane regenerated polyol according to claim 1, characterized in that: In step (2), the diol is at least one of ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol.

6. The method for preparing flame-retardant polyurethane regenerated polyol according to claim 1, characterized in that: In step (2), the melamine polyol is selected from at least one of EDS-5083L, EDS-5083H, and CN-3360.

7. The method for preparing flame-retardant polyurethane regenerated polyol according to claim 1, characterized in that: In step (2), the catalyst is at least one of potassium hydroxide, sodium hydroxide, triethylenediamine, and dibutyltin dilaurate.

8. The method for preparing flame-retardant polyurethane regenerated polyol according to claim 1, characterized in that: In step (3), the conditions of the degradation reaction are: under a nitrogen atmosphere, the reaction time is 3-6 hours, and the reaction temperature is 170-200°C.

9. A flame-retardant polyurethane regenerated polyol prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the flame-retardant polyurethane regenerated polyol according to claim 9 in the preparation of polyurethane rigid foam plastics.

Images