Slow-resilience sponge based on waste PET polyether polyol and preparation method

Abstract

The invention relates to the technical field of slow-rebound sponges, in particular to a slow-rebound sponge based on waste PET (polyethylene terephthalate) polyether polyol and a preparation method of the slow-rebound sponge. The polyether polyol based on the waste PET is obtained by taking bis (2-ethoxyl) terephthalamide obtained by aminolysis of the waste PET as a starting raw material, so that recycling of the waste PET can be realized, and the polyether polyol can also be used as a foaming raw material of slow-rebound sponge; the combined polyether is formed by mixing polyether polyol I, polyether polyol II, polyether polyol based on waste PET and polymer polyol, and parameters such as functionality, molecular weight, hydroxyl value, viscosity and epoxypropane content of the polyether polyol based on the waste PET are adjusted and controlled. The low-temperature-resistant polyurethane sponge can be stably stored at room temperature and has no crystallization phenomenon, when the low-temperature-resistant polyurethane sponge is used as a soft section of the slow-rebound sponge, the low-temperature-resistant characteristic of the slow-rebound sponge can be remarkably improved, and the problems that the slow-rebound polyurethane sponge is hard in winter, difficult to cut and poor in rebound are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of slow rebound sponge, in particular to a slow rebound sponge based on waste PET polyether polyol and a preparation method thereof. BACKGROUND

[0002] Slow rebound sponge can be plastically deformed under external pressure and does not immediately recover, and has many excellent properties such as sound insulation, shock absorption, energy absorption and good touch, and has been widely used in recent years in the fields of home, medical equipment, toys and noise reduction. However, since the slow rebound sponge becomes hard at low temperature, it loses its original comfort when used in winter for products such as mattresses, pillows and seats. The special phase separation degree and glass transition temperature of the slow rebound sponge make it have viscoelasticity. The glass transition temperature of the traditional slow rebound sponge is generally about 25 ℃, and it is sensitive to temperature. In order to make the slow rebound sponge still soft at low temperature, introducing a low-temperature soft polyether polyol into the soft segment is the key to improving the low-temperature resistance.

[0003] Polyethylene terephthalate (PET) is one of the five major engineering plastics in the world. With the continuous increase in the use of PET in packaging, clothing, building materials, biomedicine and other fields, improper disposal of waste PET will cause resource waste and environmental pollution. Therefore, under the background of "double carbon", the recycling of waste PET becomes very important. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a slow rebound sponge based on waste PET polyether polyol and a preparation method thereof, which can overcome the problems of temperature sensitivity, hardening in winter and poor rebound of the slow rebound polyurethane sponge in the prior art.

[0005] To solve the above technical problems, the technical scheme of the present application is as follows: a slow rebound sponge based on waste PET polyether polyol, the innovation point of which is that: The slow rebound sponge based on waste PET polyether polyol is obtained by two-step ring-opening polymerization of waste PET amine with ε-decalactone and propylene oxide in the above order, and the molecular structure is as shown below: , Wherein: m is 1-5, and n is 5-20.

[0006] Further, the slow rebound sponge based on waste PET polyether polyol has a functionality of 2, a molecular weight of 800-2000, a hydroxyl value of 45-110 and a viscosity of 130-250.

[0007] Further, in the waste PET-based polyether polyol, the mass fraction of bis(2-hydroxyethyl) terephthalamide is 5-15%, the mass fraction of epsilon-decalactone is 50-80%, and the mass fraction of propylene oxide is 5-50%.

[0008] The slow-rebound sponge comprises the waste PET-based polyether polyol described above, and the raw materials thereof include, in terms of mass fraction: 60-90 parts of the combined polyether, 0.05-3 parts of the foam stabilizer, 0-1.0 parts of the chain extender, 0.05-2 parts of the reactive composite catalyst, 1-4.5 parts of water, and 40-80 parts of the isocyanate, The combined polyether is composed of polyether polyol I, polyether polyol II, waste PET-based polyether polyol, and polymer polyol.

[0009] Further, the mass fraction of each material in the combined polyether is as follows: 5-20 parts of polyether polyol I, 50-80 parts of polyether polyol II, 5-15 parts of waste PET-based polyether polyol, and 0-20 parts of polymer polyol.

[0010] Further, the polyether polyol I has a functionality of 3, a molecular weight of 1500-3000, a hydroxyl value of 50-60, and a viscosity of 450-800; The polyether polyol II has a functionality of 3, a molecular weight of 3000-5000, a hydroxyl value of 30-50, and a viscosity of 900-1100; The polymer polyol has a functionality of 1.5-2.5, a molecular weight of 2000-3000, a hydroxyl value of 25-40, and a viscosity of 3000-4500; Further, the foam stabilizer is one or a combination of silicone foam stabilizer or polysiloxane-polyoxyalkylene block copolymer; The chain extender is a small-molecule diamine compound; The reactive composite catalyst is one or a combination of tin catalyst or amine catalyst; The isocyanate is 4,4'-diphenylmethane diisocyanate.

[0011] The preparation method of the slow-rebound sponge specifically comprises the following steps: (1) The combined polyether, the foam stabilizer, the chain extender, the reactive composite catalyst, water, and the isocyanate are prepared into polymer raw materials, and the raw materials are fed into a foaming machine, and open continuous low-pressure flat foam foaming is performed by the foaming machine head, and a conveying belt is arranged on the rear side of the drop plate of the foaming machine, and kraft paper is also laid on the drop plate. (2) The sponge is sprayed on the kraft paper at a speed of 80-400 kg / min by using a foaming nozzle, and the kraft paper moves forward at a speed of 2-6 m / min, thereby driving the sponge to move forward to realize foaming and conveying at the same time.

[0012] The present application has the advantages of: 1. In the present application, by adjusting and controlling the parameters such as functionality, molecular weight, hydroxyl value, viscosity and propylene oxide content of the waste PET-based polyether polyol, it can be stored stably at room temperature without crystallization, and when used as the soft segment of slow-rebound sponge, it can significantly improve the low-temperature resistance of slow-rebound sponge, avoiding the problems of hardening and poor rebound of slow-rebound polyurethane sponge in winter. 2. In the present application, by adjusting the mass fraction ratio of the combined polyether, the physical properties such as comfort, tensile strength, tear strength and elongation at break of the slow-rebound sponge can be optimized; and part of the raw materials of the composition of the combined polyether, the waste PET-based polyether polyol, are obtained from waste PFT, realizing the recycling and reuse of waste PET. 3. The waste PET-based polyether polyol provided in the present application is obtained by two-step ring-opening polymerization of bis(2-hydroxyethyl) terephthalamide obtained by aminolysis of waste PET as starting material, and ε-decalactone and propylene oxide in sequence, which not only realizes the recycling and reuse of waste PET, but also can be used as a foaming raw material for slow-rebound sponge. DETAILED DESCRIPTION

[0013] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a preferred embodiment, which will be described in detail as follows in terms of the specific implementation, structure, features and effects of the present application.

[0014] The main raw material source information of the present application is as follows, and other raw materials are ordinary commercially available raw materials without special instructions.

[0015] The waste PET-based polyether polyol is obtained by two-step ring-opening polymerization of bis(2-hydroxyethyl) terephthalamide obtained by aminolysis of waste PET as starting material, and ε-decalactone and propylene oxide in sequence, and the mass fraction of bis(2-hydroxyethyl) terephthalamide is 5-15%, the mass fraction of ε-decalactone is 50-80%, and the mass fraction of propylene oxide is 5-50%.

[0016] The molecular structure of the waste PET-based polyether polyol is as follows: , Wherein: m is 1-5, and n is 5-20. The functional group of the waste PET-based polyether polyol is 2, the molecular weight is 800-2000, the hydroxyl value is 45-110, and the viscosity is 130-250.

[0017] Waste PET-based polyether polyol A: Take 8% of bis (2-hydroxyethyl) terephthalamide, 77% of epsilon-caprolactone, and 15% of propylene oxide by mass fraction, to obtain a waste PET-based polyether polyol A with a functionality of 2, a molecular weight of 1000, a hydroxyl value of 78, and a viscosity of 187; Waste PET-based polyether polyol B: Take 8% of bis (2-hydroxyethyl) terephthalamide, 67% of epsilon-caprolactone, and 25% of propylene oxide by mass fraction, to obtain a waste PET-based polyether polyol B with a functionality of 2, a molecular weight of 1200, a hydroxyl value of 84, and a viscosity of 159; Waste PET-based polyether polyol C: Take 8% of bis (2-hydroxyethyl) terephthalamide, 52% of epsilon-caprolactone, and 40% of propylene oxide by mass fraction, to obtain a waste PET-based polyether polyol C with a functionality of 2, a molecular weight of 1500, a hydroxyl value of 93, and a viscosity of 142; Waste PET-based polyether polyol D: Take 8% of bis (2-hydroxyethyl) terephthalamide, 52% of epsilon-caprolactone, and 40% of propylene oxide by mass fraction, to obtain a waste PET-based polyether polyol C with a functionality of 2, a molecular weight of 1500, a hydroxyl value of 93, and a viscosity of 142;

[0018] A slow-rebound sponge, the raw materials of which, in terms of mass fraction, include: 60-90 parts of combined polyether, 0.05-3 parts of foam stabilizer, 0-1.0 parts of chain extender, 0.05-2 parts of reactive composite catalyst, 1-4.5 parts of water, and 40-80 parts of isocyanate, The combined polyether is composed of polyether polyol I, polyether polyol II, waste PET-based polyether polyol, and polymer polyol, and the mass fraction ratio of each material is: 5-20 parts of polyether polyol I, 50-80 parts of polyether polyol II, 5-15 parts of waste PET-based polyether polyol, and 0-20 parts of polymer polyol.

[0019] The polyether polyol I has a functionality of 3, a molecular weight of 1500-3000, a hydroxyl value of 50-60, and a viscosity of 450-800; The polyether polyol II has a functionality of 3, a molecular weight of 3000-5000, a hydroxyl value of 30-50, and a viscosity of 900-1100; The polymer polyol has a functionality of 1.5-2.5, a molecular weight of 2000-3000, a hydroxyl value of 25-40, and a viscosity of 3000-4500; The foam stabilizer is a combination of one or both of silicone foam stabilizer or polysiloxane-polyoxyalkylene block copolymer; The chain extender is a small molecule diamine compound; The reactive composite catalyst is a combination of one or both of tin catalyst or amine catalyst; The isocyanate is 4,4'-diphenylmethane diisocyanate.

[0020] The preparation method of the slow-rebound sponge specifically comprises the following steps: (1) The combined polyether, foam stabilizer, chain extender, reactive composite catalyst, water and isocyanate are made into polymer raw materials, and the raw materials are sent into a foaming machine, and open continuous low-pressure flat bubble foaming is performed by the foaming machine head, and a conveying belt is arranged at the rear side of the falling plate of the foaming machine, and kraft paper is also laid on the falling plate; (2) The sponge is sprayed on the kraft paper by the foaming nozzle at a speed of 80-400 kg / min, and the kraft paper moves forward with the conveying belt at a speed of 2-6 m / min, so as to drive the sponge to move forward together, realizing foaming and conveying at the same time.

[0021] Example 1 According to mass parts, 5 parts of polyether polyol I, 80 parts of polyether polyol II, 10 parts of waste PET-based polyether polyol A, 5 parts of polymer polyol, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst and 2.5 parts of water are taken, and the polyether polyol I, polyether polyol II, waste PET-based polyether polyol A, polymer polyol and isocyanate are first mixed to prepare a combined polyether.

[0022] The polyether polyol I has a functionality of 3, a molecular weight of 200, a hydroxyl value of 55 and a viscosity of 580; The polyether polyol II has a functionality of 3, a molecular weight of 3000, a hydroxyl value of 42 and a viscosity of 1055; The polymer polyol has a functionality of 1.5-2.5, a molecular weight of 3000, a hydroxyl value of 38 and a viscosity of 3300.

[0023] The chain extender is a small molecule diamine compound; The foam stabilizer is a silicone foam stabilizer; The reactive composite catalyst is an amine catalyst; The isocyanate is 4,4'-diphenylmethane diisocyanate.

[0024] At room temperature, the aforementioned combined polyether, silicone foam stabilizer, chain extender, amine catalyst, water, and isocyanate are used to prepare polymerization raw materials. The raw materials are then transported to a foaming machine via pipeline. The foaming machine head performs open, continuous, low-pressure flat foaming. A conveyor belt is installed behind the landing plate of the foaming machine, and kraft paper is laid on the landing plate. The polymerized material is sprayed onto the kraft paper through the foaming nozzles of the foaming machine. The flow rate of the material sprayed from the foaming nozzles is controlled at 80 kg / min. The kraft paper moves forward with the conveyor belt at a speed of 2 m / min, thereby moving the sponge forward together, achieving simultaneous foaming and conveying.

[0025] Example 2 The difference between this embodiment and Example 1 is that the mass fractions of each component in the combined polyether are as follows: 5 parts of polyether polyol I, 85 parts of polyether polyol II, 5 parts of waste PET-based polyether polyol A, 5 parts of polymer polyol, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst, and 2.5 parts of water.

[0026] Example 3 The difference between this embodiment and Example 1 is that the mass fractions of each component in the combined polyether are as follows: 5 parts of polyether polyol I, 75 parts of polyether polyol II, 15 parts of waste PET-based polyether polyol A, 5 parts of polymer polyol, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst, and 2.5 parts of water.

[0027] Example 4 The difference between this embodiment and Example 1 is that the mass fractions of each component in the combined polyether are as follows: 5 parts of polyether polyol I, 75 parts of polyether polyol II, 10 parts of waste PET-based polyether polyol A, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst, and 2.5 parts of water.

[0028] Example 5 The difference between this embodiment and Example 1 is that waste PET polyether polyol B replaces waste PET polyether polyol A in the polymerization raw materials. The mass parts of each component are as follows: 5 parts of polyether polyol I, 80 parts of polyether polyol II, 10 parts of waste PET polyether polyol B, 5 parts of polymer polyol, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst, and 2.5 parts of water.

[0029] Example 6 The difference between this embodiment and Example 1 is that waste PET polyether polyol C is used instead of waste PET polyether polyol A in the polymerization raw materials. The mass parts of each component are as follows: 5 parts of polyether polyol I, 80 parts of polyether polyol II, 10 parts of waste PET polyether polyol C, 5 parts of polymer polyol, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst, and 2.5 parts of water.

[0030] Example 7 The difference between this embodiment and Example 1 is that waste PET polyether polyol D is used instead of waste PET polyether polyol A in the polymerization raw materials. The mass parts of each component are as follows: 5 parts of polyether polyol I, 80 parts of polyether polyol II, 10 parts of waste PET polyether polyol D, 5 parts of polymer polyol, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst, and 2.5 parts of water.

[0031] Comparative Example 1 The difference between this embodiment and Example 1 is that the mass fractions of each component in the polyether combination are as follows: 5 parts of polyether polyol I, 90 parts of polyether polyol II, 5 parts of polymer polyol, 50 parts of isocyanate, 1.5 parts of silicone foam stabilizer, 0.2 parts of chain extender, 0.4 parts of amine catalyst, and 2.5 parts of water.

[0032] Comparative Example 2 Chinese patent CN116265503B discloses a low-temperature responsive slow-rebound sponge.

[0033] Comparative Example 3 Chinese patent CN113583205B discloses a slow rebound sponge.

[0034] Comparative Example 4 Chinese patent CN113999363B discloses a high load-bearing, low-temperature insensitive, slow-rebound sponge.

[0035] Comparative Example 5 Chinese patent CN111269375B discloses a low-temperature responsive, inflatable, molded slow-rebound sponge.

[0036] Comparative Example 6 Slow rebound sponge that is normally available on the market.

[0037] The performance of the slow rebound sponges prepared in Examples 1-7 and Comparative Examples 1 and 6 was characterized. The physical properties of the slow rebound sponges were tested at room temperature according to the GB / T24451-2020 test standard. The hardness change and compression rebound performance of the slow rebound sponges were tested at 25 ℃ and -5 ℃ using an Asker C-type hardness tester according to the SRIS0101 standard. The compression results were taken according to the GB / T6669-2008 test standard. The test data are shown in Table 1 below.

[0038] Temperature 25 o C]]> 25 o C]]> 25 o C]]> 25 o C]]> 25 o C]]> -5 o C]]> 25 o C]]> -5 o C]]> 25 o C]]> -5 o C]]> Test item Density (g / cm 3 )]]> Tensile strength (KPa) Tear strength (N / m) Elongation (%) Hardness C Hardness C Recovery time (s) Recovery time (s) Compression resilience (%) Compression resilience (%) Example 1 38.3 122 2.1 312 9.8 11.2 4.1 7.6 4.5 6.4 Example 2 37.7 115 2.3 307 10.2 10.6 4.1 7.2 4.7 6.7 Example 3 39.5 138 2.5 324 10.1 11.5 4.4 7.7 4.6 7.1 Example 4 37.7 125 2.5 310 9.8 10.9 4.2 7.4 4.4 6.3 Example 5 38.2 123 2.6 306 9.6 10.7 4.3 7.2 4.9 6.6 Example 6 38.5 118 2.6 301 9.3 10.4 4.4 7.5 4.3 6.5 Example 7 38.1 142 2.7 341 10.2 11.7 4.5 7.8 4.7 6.8 Comparative Example 1 37.7 63 1.1 121 10.9 19.8 5.1 10.2 11.4 19.3 Comparative Example 2 49.2 － － － 185.98 206.22 4.7 － － － Comparative Example 3 － 76.2 187.4 231.1 － － － － － － Comparative Example 4 35 － － － － － 5 － 11.4 － Comparative Example 5 59.9 111 4 107 5.5 － 6.5 － Comparative Example 6 37.1 57 1.2 119 10.7 19 4 10 10 19 Table 1. Test data of physical properties of slow rebound sponge As can be seen from the test data in Table 1, the slow rebound sponges prepared using Examples 1 to 7 all meet the national standards and are qualified products.

[0039] Comparative Example 1 is a common low-temperature resistant slow-rebound sponge formula.

[0040] Comparing Examples 1-3 with Comparative Example 6, it can be seen that when waste PET polyether polyol A is used as the soft segment introduction, it has little effect on the density of the slow rebound sponge and the recovery time at 25°C and -5°C. The tensile strength, tear strength, and elongation gradually increase with the increase of the mass fraction of waste PET polyether polyol A, and are all better than the slow rebound sponges that are normally available on the market. This is because the ester group and benzene ring structure in waste PET polyether polyol A can significantly improve the mechanical properties of the slow rebound sponge. On the other hand, the introduction of waste PET polyether polyol can significantly improve the hardness, recovery time, and compression recovery rate of the slow rebound sponge at 25°C and -5°C.

[0041] Comparing Examples 1 with Examples 5-7, it can be seen that when the proportion of propylene oxide in waste PET polyether polyol increases, the mechanical properties of slow rebound sponge will decrease, while the chain segment flexibility will increase.

[0042] Comparing Examples 1-7 with Comparative Example 1, it can be seen that the introduction of waste PET polyether polyol directly affects various properties of slow rebound sponge.

[0043] Comparing Examples 1-7 with Comparative Examples 2-5, it can be seen that the slow rebound sponge prepared using this method has better mechanical properties, as well as hardness, recovery time and compression rebound rate at 25℃ and -5℃ than the disclosed slow rebound sponge, thus solving the problem of slow rebound sponge hardening and reduced rebound performance in winter.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A polyol based on waste PET polyether, characterized in that: The waste PET-based polyether polyol is obtained by using bis(2-hydroxyethyl) terephthalamide obtained from the aminolysis of waste PET as a starting material, and then carrying out a two-step ring-opening polymerization with ε-decanoic acid lactone and propylene oxide in sequence. Its molecular structure is shown below: ， Where m is 1 to 5 and n is 5 to 20.

2. The polyol based on waste PET polyether according to claim 1, characterized in that: The polyether polyol based on waste PET has a functionality of 2, a molecular weight of 800-2000, a hydroxyl value of 45-110, and a viscosity of 130-250.

3. The polyol based on waste PET polyether according to claim 1, characterized in that: In the waste PET polyether polyol, the mass percentage of bis(2-hydroxyethyl) terephthalamide is 5-15%, the mass percentage of ε-decyl lactone is 50-80%, and the mass percentage of propylene oxide is 5-50%.

4. A slow-rebound sponge, comprising the waste PET polyether polyol as described in claim 1, characterized in that: Its raw materials, calculated by mass parts, include: 60–90 parts of polyether blend, 0.05–3 parts of foam stabilizer, 0–1.0 parts of chain extender, 0.05–2 parts of reactive composite catalyst, 1–4.5 parts of water, and 40–80 parts of isocyanate. The composite polyether is composed of polyether polyol I, polyether polyol II, polyether polyol based on waste PET, and polymer polyol.

5. The slow-rebound sponge according to claim 4, characterized in that: The mass fraction ratio of each material in the polyether composition is: 5-20 parts polyether polyol I, 50-80 parts polyether polyol II, 5-15 parts polyether polyol based on waste PET, and 0-20 parts polymer polyol.

6. The slow-rebound sponge according to claim 5, characterized in that: The polyether polyol I has a functionality of 3, a molecular weight of 1500-3000, a hydroxyl value of 50-60, and a viscosity of 450-800. The polyether polyol II has a functionality of 3, a molecular weight of 3000-5000, a hydroxyl value of 30-50, and a viscosity of 900-1100. The polymer polyol has a functionality of 1.5 to 2.5, a molecular weight of 2000 to 3000, a hydroxyl value of 25 to 40, and a viscosity of 3000 to 4500.

7. A slow-rebound sponge according to claim 5, characterized in that: The foam stabilizer is one or a combination of two of the following: an organosilicon foam stabilizer or a polysiloxane-polyoxyolefin block copolymer. The chain extender is a small molecule diamine compound; The reactive composite catalyst is one or a combination of two types of tin-based catalysts or amine catalysts; The isocyanate is 4,4'-diphenylmethane diisocyanate.

8. The method for preparing slow-rebound sponge according to any one of claims 4 to 7, characterized in that: Specifically, the following steps are included: (1) The polyether, foam stabilizer, chain extender, reactive composite catalyst, water and isocyanate are made into polymer raw materials and fed into the foaming machine. The foaming machine head performs open continuous low-pressure flat foaming. A conveyor belt is set on the rear side of the foaming machine's drop plate, and kraft paper is also laid on the drop plate. (2) The sponge is sprayed onto the kraft paper at a speed of 80-400 kg / min using a foaming nozzle, and the kraft paper moves forward with the conveyor belt at a speed of 2-6 m / min, thereby driving the sponge to move forward together, realizing foaming and conveying at the same time.

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