A flame retardant functional degradation method for unsaturated polyester and application of its product

Abstract

The present invention discloses a flame retardant functional degradation method of unsaturated polyester and the application of its products, and belongs to the technical field of upgrading and recycling of waste unsaturated polyester. The flame retardant functional degradation method of unsaturated polyester promotes the alcoholysis reaction of unsaturated polyester by constructing a phosphorus-containing flame retardant alcoholysis system to react with unsaturated polyester, introduces a phosphorus-containing structure, and obtains a flame retardant polyol with functionalized degradation products. The phosphorus-containing flame retardant alcoholysis system includes a phosphorus-containing aromatic flame retardant alcoholysis agent and an ionic liquid catalyst. The flame retardant polyol is used in the synthesis of polyurethane and unsaturated polyester materials. Through the above method, the present invention not only improves the solubility and site selectivity of the alcoholysis system of unsaturated polyester, but also can give specific properties to the degradation products, and promotes the transformation of unsaturated polyester waste into functionalized high value-added products.

Description

Technical Field

[0001] The invention relates to the technical field of upgrading and recycling waste unsaturated polyesters, and in particular to a flame retardant functional degradation method for unsaturated polyesters and application of the products thereof. Background Art

[0002] Unsaturated polyester resin is one of the most widely used thermosetting materials. It is made of a uniform mixture of unsaturated polyester polycondensate and styrene diluent. Due to its excellent mechanical, corrosion resistance, thermal stability and chemical stability, it is favored by chemical anti-corrosion, rail transit and building materials. In recent years, the annual output of unsaturated polyester resin in my country has continued to grow, reaching 3.21 million tons in 2020; the global unsaturated polyester resin market size will grow at an annual compound growth rate of 5.49% and will reach 93.323 billion yuan in 2028. However, while it is produced and used in large quantities, waste and obsolete products of thermosetting unsaturated polyester and its composite materials are also accumulating rapidly, bringing great environmental pollution, fire hazards and biosafety risks. In the structure of unsaturated polyester materials, styrene-maleic anhydride copolymer segments account for 50-60wt%. Therefore, the efficient degradation of unsaturated polyester and the effective recovery of styrene-maleic acid can be used as a breakthrough for its recycling, and a new method for the efficient recycling of unsaturated polyester can be developed.

[0003] Chemical alcoholysis can degrade polyester materials to obtain alcohol products through transesterification reactions. Commonly used alcoholysis agents include alcohol compounds such as ethylene glycol, propylene glycol, diethylene glycol and glycerol. However, the above alcoholysis agents are involved in the processes of dissolution, swelling and polyester chain scission of the unsaturated polyester surface, and it is difficult to affect the transformation of its degradation products. Summary of the invention

[0004] The purpose of the present invention is to provide a flame retardant functionalized degradation method and application of unsaturated polyester, which can not only improve the solubility and site selectivity of the alcoholysis system, but also give the degradation product specific properties, and promote the transformation of unsaturated polyester waste into functionalized high value-added products.

[0005] To achieve the above-mentioned purpose, the present invention provides a flame retardant functional degradation method for unsaturated polyester, wherein the flame retardant functional degradation method for unsaturated polyester constructs a phosphorus-containing flame retardant alcoholysis system to react with the unsaturated polyester, promotes the alcoholysis reaction of the unsaturated polyester, introduces a phosphorus-containing structure, and obtains a functional degradation product - a flame retardant polyol.

[0006] Preferably, the specific steps include:

[0007] S1. The unsaturated polyester solidified material is crushed into powder and passed through a 40-100 mesh sieve;

[0008] S2. Add the unsaturated polyester solidified powder into the phosphorus-containing flame retardant alcoholysis system and mix evenly, place in a hydrothermal kettle, and react at a temperature range of 150-210° C. for 2-10 hours to obtain a flame retardant polyol.

[0009] Preferably, the mass ratio of the unsaturated polyester cured powder to the phosphorus-containing flame retardant alcoholysis system is 1:(1-5).

[0010] Preferably, the phosphorus-containing flame retardant alcoholysis system comprises a phosphorus-containing aromatic flame retardant alcoholysis agent and an ionic liquid catalyst.

[0011] Preferably, the mass ratio of the phosphorus-containing aromatic flame retardant alcoholysis agent to the ionic liquid catalyst is (10-40):1.

[0012] Preferably, the phosphorus-containing aromatic flame retardant alcoholysis agent is one or more of the following compounds, and the molecular formula and name of the compound are as follows:

[0013] 6-((1,3-dihydroxypropan-2-yl)oxy)dibenzo[c,e][1,2]phosphine-6-oxide,

[0014] 1,3-Dihydroxypropan-2-yl diphenylphosphinate,

[0015] 1,3-Dihydroxypropane-2-yl diphenyl phosphate,

[0016] 6-((bis(2-hydroxyethyl)amino)methyl)dibenzo[c,e][1,2]phosphine-6-oxide,

[0017] ((Bis(2-hydroxyethyl)amino)methyl)diphenylphosphine oxide,

[0018] Diphenyl ((bis(2-hydroxyethyl)amino)methyl)phosphonate.

[0019] Preferably, the ionic liquid catalyst is one or more of the following ionic liquids, and the chemical formula and name of the ionic liquids are as follows:

[0020] Choline formate,

[0021] Choline acetate,

[0022] Choline bisulfate or

[0023] Phosphocholine.

[0024] Preferably, in step S2, the mass ratio of the unsaturated polyester cured powder to the flame retardant alcoholysis system is 1:(1-5).

[0025] The present invention also provides the application of the product of the flame retardant functional degradation method of the unsaturated polyester. The product is a flame retardant polyol. The flame retardant polyol is applied to synthesize polyurethane and unsaturated polyester materials.

[0026] The present invention is based on the principle of like dissolves like and molecular polarity regulation to synthesize a functionalized alcoholysis agent having similar solubility parameters to unsaturated polyester, which not only improves the solubility and site selectivity of the alcoholysis system, but also imparts specific properties to the degradation products, thereby promoting the transformation of unsaturated polyester waste into functionalized high-value-added products.

[0027] At the same time, the phosphorus-containing aromatic flame retardant alcoholysis agent has an aromatic structure similar to that of unsaturated polyester, and the phosphorus-containing structure significantly enhances the molecular polarity, which helps to improve the surface dissolution and swelling characteristics of unsaturated polyester at high temperatures, increase the contact area between unsaturated polyester and alcoholysis system, and thus promote the occurrence of the degradation process. In addition, efficient catalysts also help to improve the degradation efficiency. Non-metallic ionic liquids have the advantages of strong designability, low volatility, and good thermal stability, and their anions and cations have a synergistic effect on the selection of alcoholysis reaction sites, and together with phosphorus-containing aromatic flame retardant alcoholysis agents, they constitute an efficient alcoholysis system.

[0028] Therefore, the present invention adopts the above-mentioned flame retardant functional degradation method and application of unsaturated polyester, which has the following beneficial effects:

[0029] (1) The phosphorus-containing aromatic flame retardant alcoholysis agent introduces a phosphorus-containing structure, which can not only enhance the polarity of the alcoholysis agent, but also introduce the phosphorus-containing flame retardant structure into the degradation product through the alcoholysis reaction, thereby obtaining a flame retardant functionalized high value-added degradation product.

[0030] (2) The introduction of aromatic structure into phosphorus-containing aromatic flame retardant alcoholysis agent makes its structure similar to that of unsaturated polyester, which conforms to the principle of like dissolves like.

[0031] (3) Non-metallic ionic liquid catalysts can promote the occurrence of alcoholysis reactions and can be effectively recovered by water washing after the reaction for recycling.

[0032] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the reaction scheme of Example 1;

[0034] Figure 2 It is the reaction route diagram of comparative example 1;

[0035] Figure 3 is 6-((1,3-dihydroxypropan-2-yl)oxy)dibenzo[c,e][1,2]phosphine-6-oxide in Example 1 1 HNMR spectrum;

[0036] Figure 4 is the nuclear magnetic resonance of choline formate in Example 1 1 HNMR spectrum;

[0037] Figure 5 FTIR curves of the products prepared in Example 1 and Comparative Example 1;

[0038] Figure 6 The stability comparison curves of the products prepared in Example 1 and Comparative Example 1 are shown;

[0039] Figure 7 The flame retardant performance comparison curve of the products prepared in Example 1 and Comparative Example 1 is shown. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0041] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0042] In addition, it should be understood that although this specification is described according to the implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. These other implementation modes are also covered within the protection scope of the present invention.

[0043] Example 1

[0044] This embodiment provides a flame retardant functional degradation method for unsaturated polyester, wherein 20g of 6-((1,3-dihydroxypropan-2-yl)oxy)dibenzo[c,e][1,2]phosphine-6-oxide and 1g of choline formate are mixed evenly to form a phosphorus-containing flame retardant alcoholysis system, wherein 6-((1,3-dihydroxypropan-2-yl)oxy)dibenzo[c,e][1,2]phosphine-6-oxide 1 H NMR spectrum Figure 1 As shown, the NMR of choline formate 1 HNMR spectrum Figure 2 shown.

[0045] 5 g of unsaturated polyester powder passed through a 50-mesh sieve was added to the phosphorus-containing flame retardant alcoholysis system, placed in a hydrothermal kettle, reacted at 190° C. for 5 h, and washed with water several times to obtain the prepared product - flame retardant polyol. The reaction route is as follows: Figure 3 shown.

[0046] Comparative Example 1

[0047] 20g of ethylene glycol and 1g of choline formate were mixed evenly and then added with 5g of unsaturated polyester solidified powder that had passed through a 50-mesh sieve, placed in a hydrothermal kettle, reacted at 190°C for 5h, and washed with water several times to obtain the prepared product - conventional non-flame retardant degradation product. The reaction route is as follows Figure 4 shown.

[0048] Figure 5 FTIR curves of the flame retardant polyol prepared in Example 1 and the conventional non-flame retardant degradation product prepared in Comparative Example 1. The flame retardant polyol in Example 1 has a FTIR curve of 1377 cm -1 The P=O peak appears at , indicating the introduction of phosphorus-containing structure.

[0049] Figure 6 : is a comparison chart of the thermal stability of the flame retardant polyol prepared in Example 1 and the conventional non-flame retardant degradation product prepared in Comparative Example 1. The carbon residue rate of the conventional non-flame retardant degradation product obtained in Comparative Example 1 at 800°C is only 11.09 wt%, and the carbon residue rate of the flame retardant polyol obtained in Example 1 at 800°C increases to 28.91 wt%. Therefore, compared with the conventional non-flame retardant degradation product obtained in Comparative Example 1, the flame retardant polyol obtained in Example 1 has higher high temperature thermal stability.

[0050] Figure 7 This is a flame retardant performance comparison chart of the flame retardant polyol prepared in Example 1 and the conventional non-flame retardant degradation product prepared in Comparative Example 1. By comparing the conventional non-flame retardant degradation product obtained in Comparative Example 1, the peak heat release rate of the flame retardant polyol obtained in Example 1 is reduced from 264 W / g to 133 W / g, with a reduction of up to 49.6%. Therefore, the flame retardant polyol prepared in this Example 1 has excellent flame retardant properties.

[0051] Example 2

[0052] This embodiment provides a flame retardant functional degradation method for unsaturated polyester, wherein 20g of 1,3-dihydroxypropane-2-yldiphenylphosphinate and 2g of choline acetate are mixed evenly to form a phosphorus-containing flame retardant alcoholysis system. 5g of unsaturated polyester powder passing through a 100-mesh sieve is added to the phosphorus-containing flame retardant alcoholysis system, placed in a hydrothermal kettle, reacted at 200°C for 10h, and washed with water multiple times to obtain a flame retardant polyol.

[0053] Example 3

[0054] This embodiment provides a flame retardant functional degradation method for unsaturated polyester, wherein 20g of 6-((bis(2-hydroxyethyl)amino)methyl)dibenzo[c,e][1,2]phosphine-6-oxide and 1g of choline formate are mixed evenly to form a phosphorus-containing flame retardant alcoholysis system. 5g of unsaturated polyester powder passing through a 100-mesh sieve is added to the phosphorus-containing flame retardant alcoholysis system, placed in a hydrothermal kettle, reacted at 210°C for 10h, and washed with water multiple times to obtain a flame retardant polyol.

[0055] Therefore, the present invention provides a method for improving the solubility and site selectivity of the alcoholysis system of unsaturated polyester and imparting specific properties to the degradation products, thereby promoting the transformation of unsaturated polyester waste into functionalized high-value-added products.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A flame retardant functional degradation method for unsaturated polyester, characterized in that: The flame retardant functionalized degradation method of unsaturated polyester comprises constructing a phosphorus-containing flame retardant alcoholysis system to react with the unsaturated polyester, promoting the alcoholysis reaction of the unsaturated polyester, introducing a phosphorus-containing structure, and obtaining a functionalized degradation product, wherein the functionalized degradation product is a flame retardant polyol; The phosphorus-containing flame retardant alcoholysis system comprises a phosphorus-containing aromatic flame retardant alcoholysis agent and an ionic liquid catalyst; The mass ratio of the phosphorus-containing aromatic flame retardant alcoholysis agent to the ionic liquid catalyst is (10-40): 1; The phosphorus-containing aromatic flame retardant alcoholysis agent is one or more of 6-((1,3-dihydroxypropan-2-yl)oxy)dibenzo[c,e][1,2]oxaphosphine-6-oxide, 1,3-dihydroxypropan-2-yl diphenyl phosphinate, 1,3-dihydroxypropan-2-yl diphenyl phosphate, 6-((bis(2-hydroxyethyl)amino)methyl)dibenzo[c,e][1,2]oxaphosphine-6-oxide, ((bis(2-hydroxyethyl)amino)methyl)diphenylphosphine oxide, and ((bis(2-hydroxyethyl)amino)methyl)diphenyl phosphine ester; The ionic liquid catalyst is one or more of choline formate, choline acetate, choline hydrogen sulfate or choline phosphorylation.

2. The flame retardant functional degradation method of unsaturated polyester according to claim 1, characterized in that: The specific steps are as follows: S1. The unsaturated polyester solidified material is crushed into powder and passed through a 40-100 mesh sieve; S2. Add the unsaturated polyester solidified powder into the phosphorus-containing flame retardant alcoholysis system and mix evenly, place in a hydrothermal kettle, and react at a temperature range of 150-210° C. for 2-10 hours to obtain a flame retardant polyol.

3. The flame retardant functional degradation method of unsaturated polyester according to claim 2, characterized in that: In step S2, the mass ratio of the unsaturated polyester cured powder to the phosphorus-containing flame retardant alcoholysis system is 1:(1-5).

4. A flame retardant polyol, characterized in that: The flame retardant polyol is obtained by degradation using the flame retardant functional degradation method of an unsaturated polyester according to any one of claims 1 to 3.

5. A flame retardant polyol according to claim 4, characterized in that: The flame retardant polyol is used in synthesizing polyurethane and unsaturated polyester materials.

Images