A chain extender based on waste pet, polyurethane sponge and preparation method

Abstract

The application relates to the technical field of polyurethane foams, in particular to a chain extender based on waste PET, a polyurethane sponge and a preparation method. The chain extender based on waste PET is obtained by degrading waste PET by using 3,5-dimethyl-4-(2-hydroxyethoxy)benzaldehyde as an alcoholysis agent to obtain an alcoholysis product, and then reacting the alcoholysis product with a dihydric alcohol organic substance, avoiding the dependence on petroleum-based non-renewable polyols in the preparation process of the existing polyurethane foam, and realizing the recycling of waste PET. The chain extender based on waste PET is used for preparing a degradable polyurethane foam. The acetal structure in the chain extender based on waste PET can be decomposed under certain external action, that is, the polyurethane foam can be decomposed in the form of decomposition of the chain extender based on waste PET, the degradation ability of the polyurethane foam is improved, and thus the degradable polyurethane foam with low carbon and green properties is obtained.

Description

Technical Field

[0001] This invention relates to the field of polyurethane foam technology, and in particular to a chain extender based on waste PET, a polyurethane sponge, and a preparation method thereof. Background Technology

[0002] Polyols are an important intermediate in the preparation of polyurethane foam. Traditional polyols are mainly petroleum-based, obtained from fossil resources. However, fossil resources are not only non-renewable, but their use also brings many environmental problems. On the other hand, polyethylene terephthalate (PET) is one of the world's top five engineering plastics, with a global production capacity exceeding 80 million tons per year by the end of 2023. With the continuous growth in the use of PET in packaging, clothing, building materials, and biomedicine, improper disposal after waste will lead to resource waste and environmental pollution.

[0003] With economic development and increased environmental awareness, if waste PET can be depolymerized into high-value-added monomers and used for the synthesis of polyols, it will open up a new path for the recycling and reuse of waste PET, further reduce the polyurethane foam industry's dependence on fossil resources, and thus obtain low-carbon and green polyurethane foam plastics. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a chain extension agent based on waste PET that can solve the problem of dependence on petroleum-based non-renewable polyols in the existing polyurethane foam preparation process and realize the recycling of waste PET and its application.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: a chain extension agent based on waste PET, the innovation of which lies in that: the chain extension agent based on waste PET is formed by using 3,5-dimethyl-4-(2-hydroxyethoxy)benzaldehyde as an alcoholysis agent to degrade waste PET to obtain alcoholysis products, and then using the alcoholysis products to react with diol organic compounds, and the molecular structure of the chain extension agent based on waste PET is shown below:

[0006] ,

[0007] n is an even number;

[0008] or

[0009] ,

[0010] m is an integer greater than 1.

[0011] Furthermore, the alcoholysis product has the following molecular structure:

[0012] .

[0013] Furthermore, the diol organic compound is one of 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and hexaethylene glycol.

[0014] Furthermore, the chain extender based on waste PET is used to prepare biodegradable polyurethane foam.

[0015] Furthermore, the biodegradable polyurethane foam is polymerized from the following components in parts by weight: 50-90 parts isocyanate, 60-100 parts polyether polyol, 0.05-3 parts foam stabilizer, 0.05-2 parts reactive composite catalyst, 0-5 parts chain extender based on waste PET, and 1-4.5 parts water.

[0016] Furthermore, the isocyanate is 4,4'-diphenylmethane diisocyanate.

[0017] Furthermore, the foam stabilizer is at least one of an organosilicon foam stabilizer or a polysiloxane-polyoxyolefin block copolymer.

[0018] Furthermore, the reactive composite catalyst is at least one of a tin-based catalyst or an amine-based catalyst.

[0019] The advantages of this invention are:

[0020] 1. This invention uses waste PET alcoholysis products and diol organic compounds as raw materials to synthesize a chain extension agent based on waste PET, avoiding the dependence on petroleum-based non-renewable polyols in the existing polyurethane foam preparation process, and realizing the recycling of waste PET.

[0021] 2. The polyurethane foam utilizes chain extenders based on waste PET. These chain extenders contain methyl, ester, and aromatic groups, along with unique molecular structures, which improve the tensile strength, tear strength, and elongation of the biodegradable polyurethane foam, thus broadening its application range. Furthermore, the acetal structure in the waste PET chain extenders can decompose under certain external influences. This chain extender-based decomposition process allows the polyurethane foam to decompose, enhancing its degradation capabilities and resulting in low-carbon, green biodegradable polyurethane foam. Detailed Implementation

[0022] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0023] A chain extension agent based on waste PET is obtained by using 3,5-dimethyl-4-(2-hydroxyethoxy)benzaldehyde as an alcoholysis agent to degrade waste PET to obtain an alcoholysis product, which has the following molecular structure:

[0024] .

[0025] The chain extender based on waste PET was obtained by reacting the alcoholysis product with diol-based organic compounds. The molecular structure of the chain extender based on waste PET is shown below:

[0026] ,

[0027] n is an even number;

[0028] or

[0029] ,

[0030] m is an integer greater than 1;

[0031] Diols are one of the following: 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and hexaethylene glycol.

[0032] Chain extenders based on waste PET can be used to prepare biodegradable polyurethane foam.

[0033] Biodegradable polyurethane foam is formed by mixing, stirring, polymerizing, and foaming the following components in parts by weight within a foaming machine:

[0034] 50-90 parts isocyanate, 60-100 parts polyether polyol, 0.05-3 parts foam stabilizer, 0.05-2 parts reactive composite catalyst, 0-5 parts chain extender based on waste PET, and 1-4.5 parts water.

[0035] The isocyanate is 4,4'-diphenylmethane diisocyanate.

[0036] The foam stabilizer is at least one of organosilicon foam stabilizer or polysiloxane-polyoxyolefin block copolymer.

[0037] The reactive composite catalyst is at least one of tin-based catalysts or amine-based catalysts.

[0038] This invention uses waste PET alcoholysis products and diol organic compounds as raw materials to synthesize a chain extension agent based on waste PET, avoiding the dependence on petroleum-based non-renewable polyols in the existing polyurethane foam preparation process, and realizing the recycling of waste PET.

[0039] The polyurethane foam incorporates chain extenders based on waste PET. These chain extenders contain methyl, ester, and aromatic groups, along with unique molecular structures, which improve the tensile strength, tear strength, and elongation of the biodegradable polyurethane foam, thus broadening its application range. The acetal structure in these waste PET chain extenders can decompose under certain external conditions. For example, at acidic room temperature, the acetal structure breaks down, generating aldehyde and hydroxyl groups. This chain extender-based decomposition process enables the polyurethane foam to decompose, enhancing its degradation capabilities and resulting in low-carbon, green biodegradable polyurethane foam.

[0040] Example 1

[0041] Biodegradable polyurethane foam is composed of the following components in parts by weight:

[0042] 70 parts of a polyether polyol with a molecular weight of 3000, functionality of 3, hydroxyl value of 56, and viscosity of 460, and 20 parts of which are used to dissolve chain extenders based on waste PET.

[0043] 20 parts of a polyether polyol with a molecular weight of 2000, functionality of 3, hydroxyl value of 78, and viscosity of 210;

[0044] 20 parts of a polymeric polyol with a molecular weight of 3000, functionality of 1.5, hydroxyl value of 28, and viscosity of 3000;

[0045] The composition includes 55 parts MDI, 1.5 parts silicone foam stabilizer, 0.5 parts amine catalyst, 2.5 parts water, and 3.5 parts chain extender based on waste PET, with the structural formula of the chain extender based on waste PET shown below:

[0046] .

[0047] Example 2

[0048] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0049] .

[0050] Example 3

[0051] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0052] .

[0053] Example 4

[0054] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0055] .

[0056] Example 5

[0057] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0058] .

[0059] Example 6

[0060] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0061] .

[0062] Example 7

[0063] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0064] .

[0065] Example 8

[0066] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0067] .

[0068] Example 9

[0069] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except for the chain extender based on waste PET, whose structural formula is shown below:

[0070] .

[0071] Comparative Example 1

[0072] The amounts of other components used in the preparation of biodegradable polyurethane foam are the same as in Example 1, except that the chain extender based on waste PET is replaced with a commercially available chain extender used in polyurethane foaming.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that the amount of chain extender based on waste PET is 5.0 parts, while the amounts of other components remain unchanged.

[0075] The polyurethane foams prepared in Examples 1-9 and Comparative Example 1 were subjected to physical property tests, and the test results are shown in Table 1.

[0076]

[0077] Table 1

[0078] In summary, by introducing chain extenders based on waste PET into the polymerization raw materials and utilizing the reaction of hydroxyl groups in the chain extenders with isocyanates, the chain extenders based on waste PET are covalently linked to the polyurethane foam molecular chains. Compared with ordinary polyurethane foam in the comparative example, the density, hardness, tensile strength, tear strength, and elongation are all significantly improved.

[0079] Comparing Examples 1-5, it can be seen that as the n value in the molecular structure of the chain extender based on waste PET increases, the density, hardness, tensile strength, tear strength, and elongation of the polyurethane foam all increase to a certain extent. This is because as the molecular chain length increases, the entanglement between molecules becomes tighter, resulting in an improvement in the strength and elongation of the material.

[0080] Comparative examples 6-9 show that as the value of m in the molecular structure of the chain extender based on waste PET increases, the density, hardness, and elongation of the polyurethane foam all increase to a certain extent, but the tensile strength and tear strength decrease to a certain extent. This is because the ether bonds make the molecular chains easy to bend and slide, making it difficult to resist external forces, which in turn leads to a certain degree of reduction in the rigidity of the material. However, the flexible ether bonds easily absorb impact energy and can promote local deformation of the material, thus increasing the elongation of the foam to a certain extent.

[0081] Comparing Example 1 and Example 6, it can be seen that when ether bonds are introduced into the molecular structure of the chain extender based on waste PET, the tensile strength and tear strength of the foam decrease to a certain extent, but the elongation increases to a certain extent. This is because ether bonds make the molecular chains easy to bend and slide, making it difficult to resist external forces, which in turn leads to a certain degree of reduction in the rigidity of the material. However, the flexible ether bonds easily absorb impact energy and can promote local deformation of the material, thus the elongation of the foam increases to a certain extent.

[0082] Comparing Example 1 with Comparative Example 1, it can be seen that compared with commercially available chain extenders used in polyurethane foaming, the introduction of chain extenders based on waste PET during foaming can significantly improve properties such as foam density, hardness, tensile strength, tear strength, and elongation. This is because the molecular structure of chain extenders based on waste PET contains groups such as methyl, ester, and aromatic rings, as well as special molecular structures, which can improve the physical properties of the material.

[0083] Comparing Example 1 and Comparative Example 2, it can be seen that when the amount of chain extender based on waste PET added increases from 3.5 parts to 5.0 parts, the foam density, hardness, tensile strength, tear strength and elongation all increase. This is a result of the increase in the number of rigid aromatic rings and polar ester groups in the foam.

[0084] 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 chain extender based on waste PET, characterized in that: The chain extender based on waste PET is formed by degrading waste PET with 3,5-dimethyl-4-(2-hydroxyethoxy)benzaldehyde as an alcoholysis agent to obtain alcoholysis products, and then reacting these alcoholysis products with diol organic compounds. The molecular structure of the chain extender based on waste PET is shown below: ， n is an even number; or ， m is an integer greater than 1.

2. The chain extender based on waste PET according to claim 1, characterized in that: The alcoholysis product has the following molecular structure: 。 3. The chain extender based on waste PET according to claim 1, characterized in that: The diol organic compound is one of 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and hexaethylene glycol.

4. The application of a chain extender based on waste PET according to any one of claims 1-3, characterized in that: The chain extender based on waste PET is used to prepare biodegradable polyurethane foam.

5. The application of a chain extender based on waste PET according to claim 4, characterized in that: The biodegradable polyurethane foam is polymerized from the following components in parts by weight: 50-90 parts isocyanate, 60-100 parts polyether polyol, 0.05-3 parts foam stabilizer, 0.05-2 parts reactive composite catalyst, 3.5-5 parts chain extender based on waste PET, and 1-4.5 parts water. The reactive composite catalyst is at least one of tin-based catalysts or amine-based catalysts.

6. The application of a chain extender based on waste PET according to claim 5, characterized in that: The isocyanate is 4,4'-diphenylmethane diisocyanate.

7. The application of a chain extender based on waste PET according to claim 5, characterized in that: The foam stabilizer is at least one of an organosilicon foam stabilizer or a polysiloxane-polyoxyolefin block copolymer.

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