A hydrophilic, flexible polyurethane sponge and a method for making the same

Abstract

The application belongs to the field of polyurethane materials, and provides a hydrophilic and flexible polyurethane sponge preparation method, which comprises the following steps: step one, uniformly mixing isocyanate, polylactic acid polyol, catalyst, hydrophilic agent and water, and reacting at room temperature to obtain a reaction liquid; step two, foaming and curing the reaction liquid to obtain the polyurethane sponge material. In the process of preparing the hydrophilic and flexible polyurethane sponge, a polylactic acid polyol with a specific structure is used, the polylactic acid polyol contains alcohol hydroxyl and a polylactic acid segment, the content of alcohol hydroxyl in the molecule is appropriate, and the appropriate crosslinking strength can be provided, the finally prepared bio-based polyurethane sponge has good flexibility and hydrophilicity, and has a good application prospect; moreover, the bio-based polyurethane sponge has the advantages of extremely low cost, is suitable for large-scale batch production, and is conducive to the application of the prepared hydrophilic and flexible polyurethane sponge.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials, specifically relating to a hydrophilic, flexible polyurethane sponge and its preparation method. Background Technology

[0002] Polyurethane foam is foam with a density of less than 50 kg / m³. 3 The following materials include hydrophilic polyurethane foam, a type of polyurethane material with excellent hydrophilic properties. Due to the introduction of hydrophilic groups or segments into its molecular chain, its ability to absorb and retain water is significantly improved. This characteristic makes hydrophilic polyurethane foam perform better in environments that require rapid water absorption and maintenance of a certain humidity. It can be applied to furniture, cosmetic accessories, aquaculture and other fields, and has a wider range of application prospects.

[0003] Hydrophilic polyurethane foam is a type of polyurethane foam prepared using hydrophilic monomers as polymer raw materials. One paper discloses a hydrophilic polyurethane foam material prepared using polymeric polyols, isocyanates, blowing agents, catalysts, foam leveling agents, and cell openers. However, the polylactic acid polyol used in this method has a simple molecular structure and poor molecular flexibility, resulting in polyurethane foam with poor flexibility. Although it possesses some hydrophilicity, its hydrophilicity is not yet optimal. Summary of the Invention

[0004] To address the issues of poor flexibility and insufficient hydrophilicity in existing bio-based polyurethane sponges, this invention provides a hydrophilic, flexible polyurethane sponge and its preparation method.

[0005] The preparation method of this hydrophilic, flexible polyurethane foam includes the following steps:

[0006] Step 1: Mix isocyanate, polylactic acid polyol, catalyst, hydrophilic agent and water evenly, and react at room temperature to obtain a reaction solution;

[0007] Step 2: The reaction solution is foamed and cured to obtain the polyurethane foam material.

[0008] The structural formula of the polylactic acid polyol mentioned in step one is as follows:

[0009]

[0010] Where m is 3-20 and n is 3-20.

[0011] Furthermore, the mass ratio of the isocyanate, polylactic acid polyol and water added in step one is (40-50):100:(2-3).

[0012] Furthermore, the mass ratio of the polylactic acid polyol, catalyst, and hydrophilic agent added in step one is 100:(0.2-0.5):(10-15).

[0013] Furthermore, the catalyst mentioned in step one is stannous octoate or triethylenediamine.

[0014] Furthermore, the hydrophilic agent mentioned in step one is one of polyethylene glycol-modified polysiloxanes.

[0015] Further, the isocyanate mentioned in step one is selected from one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

[0016] Furthermore, the polylactic acid polyol mentioned in step one is prepared by the following method:

[0017] Step 1: Mix zinc salt, organic ammonium salt and bis(ethylene carbonate) ether and heat to react, thus obtaining an in-situ catalyst;

[0018] Step 2: Add the purified LA monomer to the in-situ catalyst to react and obtain the product.

[0019] Further, the mass ratio of the zinc salt, organic ammonium salt and bis(ethylene carbonate) ether in step 1 is 1:(10-50):(30-50).

[0020] Further, the mass ratio of the bis(ethylene carbonate) ether in step 1 to the LA monomer in step 2 is 1:(30-60).

[0021] The present invention also provides a hydrophilic, flexible polyurethane sponge.

[0022] The hydrophilic, flexible polyurethane sponge is prepared by any of the methods described above for preparing hydrophilic, flexible polyurethane sponges.

[0023] The beneficial effects of this invention are as follows:

[0024] (1) The present invention uses polylactic acid polyol with a specific structure, hydrophilic agent and other substances as raw materials to prepare polyurethane sponge. Since the polylactic acid polyol contains segments with good flexibility and has two hydroxyl groups in its molecular structure, it can provide suitable crosslinking strength, so that the prepared polyurethane sponge has good flexibility. Furthermore, due to the combination of polylactic acid segments of polylactic acid polyol and hydrophilic agent, the prepared polyurethane has excellent hydrophilicity.

[0025] (2) This invention uses a new catalytic system with high catalytic activity to prepare polylactic acid polyol with high safety at low cost. Using this polylactic acid polyol to prepare polyurethane sponge can reduce the preparation cost of polyurethane sponge, which is conducive to the promotion and application of polyurethane sponge. Attached Figure Description

[0026] Figure 1 The flowchart illustrates the preparation method of the hydrophilic, flexible polyurethane sponge provided by this invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but this should not be construed as limiting the scope of the present invention.

[0028] The method of this invention uses low-cost, flexible polylactic acid polyol as raw material, and adds a specific hydrophilic agent to the polylactic acid polyol to further improve its hydrophilicity. Then, it prepares polyurethane foam through foaming, aging and other steps. The prepared polyurethane foam has excellent flexibility and hydrophilicity.

[0029] See Figure 1 A method for preparing a hydrophilic, flexible polyurethane sponge, characterized by comprising the following steps:

[0030] Step 1: Mix isocyanate, polylactic acid polyol, catalyst, hydrophilic agent and water evenly, and react at room temperature to obtain a reaction solution;

[0031] Step 2: The reaction solution is foamed and cured to obtain the polyurethane foam material.

[0032] The structural formula of the polylactic acid polyol mentioned in step one is as follows:

[0033]

[0034] Where m is 3-20 and n is 3-20.

[0035] The method of this invention uses low-cost, flexible polylactic acid polyol as raw material, and adds a specific hydrophilic agent to the polylactic acid polyol to further improve its hydrophilicity. Then, it prepares polyurethane foam through foaming, aging and other steps. The prepared polyurethane foam has excellent flexibility and hydrophilicity.

[0036] Example 1

[0037] I. Preparation of polylactic acid polyols:

[0038] Step 1: Mix 0.5g of bis(ethylene carbonate) ether, 0.01g of zinc chloride, and 0.3g of tetrabutylammonium chloride, and react at 200℃ and 1MPa pressure for 1h to obtain an in-situ catalyst;

[0039] Step 2: Then, 18g of LA monomer was added to the in-situ catalyst and reacted at 160℃ for 1h to obtain the product;

[0040] Step 3: After the reaction is complete, methanol is added to the product for precipitation. After removing the solvent, the product is dried under vacuum at 40°C for 48 hours to obtain polylactic acid polyol.

[0041] II. Preparation of hydrophilic, flexible polyurethane foam

[0042] Take 4.5g of diphenylmethane diisocyanate, 10g of the above-mentioned polylactic acid polyol, 0.02g of dibutyltin dilaurate, 1g of polyethylene glycol-modified polysiloxane (Maihao Technology HD-220) and 0.25g of water, mix them evenly, and react at room temperature for 1.5h to obtain a reaction solution; foam and mature the reaction solution under normal pressure for 24h to obtain the polyurethane sponge material.

[0043] Example 2

[0044] I. Preparation of polylactic acid polyols:

[0045] Step 1: Mix 0.4g of bis(ethylene carbonate) ether, 0.01g of zinc acetate and 0.3g of dimethylaminopyridine, and react at 200℃ and 1MPa pressure for 1.5h to obtain an in-situ catalyst;

[0046] Step 2: Then, 18g of LA monomer was added to the in-situ catalyst and reacted at 180℃ for 1h to obtain the product;

[0047] Step 3: After the reaction is complete, methanol is added to the product for precipitation. After removing the solvent, the product is dried under vacuum at 40°C for 48 hours to obtain polylactic acid polyol.

[0048] II. Preparation of hydrophilic, flexible polyurethane foam

[0049] Take 4g of toluene diisocyanate, 10g of the above-mentioned polylactic acid polyol, 0.03g of stannous octoate, 1g of polyethylene glycol-modified polysiloxane (Maihao Technology HD-220) and 0.2g of water, mix them evenly, and react at room temperature for 1.5h to obtain a reaction solution; foam and mature the reaction solution under normal pressure for 24h to obtain the polyurethane sponge material.

[0050] Example 3

[0051] I. Preparation of polylactic acid polyols:

[0052] Step 1: Mix 0.3g of 1,4-butanediol diglycidyl ether, 0.01g of zinc chloride, and 0.3g of tetrabutylammonium chloride, and react at 200℃ and 1MPa pressure for 1.5h to obtain an in-situ catalyst;

[0053] Step 2: Then, 18g of LA monomer was added to the in-situ catalyst and reacted at 130℃ for 2h to obtain the product;

[0054] Step 3: After the reaction is complete, methanol is added to the product for precipitation. After removing the solvent, the product is dried under vacuum at 40°C for 48 hours to obtain polylactic acid polyol.

[0055] II. Preparation of hydrophilic, flexible polyurethane foam

[0056] Take 5g of isophorone diisocyanate, 10g of the above-mentioned polylactic acid polyol, 0.04g of di(dodecyl sulfide) dibutyltin, 1.2g of polyethylene glycol modified polysiloxane (Maihao Technology ZL-480) and 0.3g of water, mix them evenly, react at room temperature and mature for 24h to obtain a hydrophilic sponge.

[0057] Example 4

[0058] I. Preparation of polylactic acid polyols:

[0059] Step 1: Mix 0.5g diglycidyl ether, 0.01g zinc chloride, and 0.5g tetrabutylammonium iodide, and react at 200℃ and 1MPa pressure for 1h to obtain an in-situ catalyst;

[0060] Step 2: Then, 18g of LA monomer was added to the in-situ catalyst and reacted at 160℃ for 2h to obtain the product;

[0061] Step 3: After the reaction is complete, methanol is added to the product for precipitation. After removing the solvent, the product is dried under vacuum at 40°C for 48 hours to obtain polylactic acid polyol.

[0062] II. Preparation of hydrophilic, flexible polyurethane foam

[0063] Take 4g of hexamethylene diisocyanate, 10g of the above polylactic acid polyol, 0.05g of dibutyltin diacetate, 1.5g of polyethylene glycol-modified polysiloxane (Maihao Technology HD-220) and 0.3g of water, mix them evenly, react at room temperature and mature for 24h to obtain a hydrophilic sponge.

[0064] Example 5

[0065] I. Preparation of polylactic acid polyols:

[0066] Step 1: Mix 0.5g diglycidyl ether, 0.01g zinc bromide, and 0.1g tetrabutylammonium bromide, and react at 210℃ and 1MPa pressure for 1h to obtain an in-situ catalyst;

[0067] Step 2: Then, 18g of LA monomer was added to the in-situ catalyst and reacted at 160℃ for 1h to obtain the product;

[0068] Step 3: After the reaction is complete, ethanol is added to the product for precipitation. After removing the solvent, the product is dried under vacuum at 40°C for 48 hours to obtain polylactic acid polyol.

[0069] II. Preparation of hydrophilic, flexible polyurethane foam

[0070] Take 4.5g of toluene diisocyanate, 10g of the above polylactic acid polyol, 0.02g of dibutyltin dilaurate, 1g of polyethylene glycol-modified polysiloxane (Maihao Technology HD-220) and 0.2g of water, mix them evenly, react at room temperature and mature for 24h to obtain a hydrophilic sponge.

[0071] Example 6

[0072] I. Preparation of polylactic acid polyols:

[0073] Step 1: Mix 0.5g diglycidyl ether, 0.01g zinc bromide, and 0.30g tetrabutylammonium iodide, and react at 220℃ and 1MPa pressure for 2h to obtain an in-situ catalyst;

[0074] Step 2: Then, 18g of LA monomer was added to the in-situ catalyst and reacted at 160℃ for 1h to obtain the product;

[0075] Step 3: After the reaction is complete, methanol is added to the product for precipitation. After removing the solvent, the product is dried under vacuum at 40°C for 48 hours to obtain polylactic acid polyol.

[0076] II. Preparation of hydrophilic, flexible polyurethane foam

[0077] Take 5g of toluene diisocyanate, 10g of the above-mentioned polylactic acid polyol, 0.03g of dibutyltin dilaurate, 1.3g of polyethylene glycol modified polysiloxane (Guangsiyuan Polyurethane Materials Co., Ltd. GSY-2510) and 0.2g of water, mix them evenly, react at room temperature, and mature for 24h to obtain a hydrophilic sponge.

[0078] Comparative Example 1

[0079] I. Preparation of hydrophilic, flexible polyurethane foam

[0080] Take 4.5g of diphenylmethane diisocyanate, 10g of polylactic acid polyol (Mingshan Biotechnology Co., Ltd., MS-PLLA), 0.02g of dibutyltin dilaurate, 1g of polyethylene glycol modified polysiloxane (Maihao Technology HD-220) and 0.25g of water, mix them evenly, and react at room temperature for 1.5h to obtain a reaction solution; foam and cure the reaction solution under normal pressure for 24h to obtain a hydrophilic and flexible polyurethane sponge.

[0081] The hydrophilicity and flexibility of the polyurethane sponges prepared in the examples and comparative examples were tested, and the test results are shown in Table 1.

[0082] The water absorption rate was determined in accordance with GB / T1034-2008;

[0083] Indentation hardness was tested in accordance with GB / T-10802-2006 standard.

[0084] Table 1

[0085] Test Items Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Water absorption rate 830％ 780％ 810％ 590％ 580％ 620％ 569％ Indentation hardness 1.62 1.67 1.68 1.63 1.66 1.68 1.80

[0086] The test results above show that the bio-based polyurethane sponge prepared using the method of this invention has good hydrophilicity and flexibility. In contrast, the polyurethane sponge prepared using existing polylactic acid polyols in Comparative Example 1 has relatively poor hydrophilicity and flexibility due to the poor flexibility and hydrophilicity of the polylactic acid polyol segments.

[0087] Furthermore, the cost of polyurethane sponges prepared from petroleum-based polylactic acid polyols using existing reported technologies is 30-39 yuan / kg, while the cost of commercially available hydrophilic and flexible polyurethane sponges is 30-35 yuan / kg. The cost of hydrophilic bio-based polyurethane prepared using the method of this invention is 25-50 yuan / kg, indicating that the method of this invention can significantly reduce the preparation cost of hydrophilic and flexible polyurethane sponges.

Claims

1. A method for preparing a hydrophilic, flexible polyurethane sponge, characterized in that, Includes the following steps: Step 1: Mix isocyanate, polylactic acid polyol, catalyst, hydrophilic agent and water evenly, and react at room temperature to obtain a reaction solution; Step 2: The reaction solution is foamed and cured to obtain the polyurethane sponge; The polylactic acid polyol mentioned in step one is prepared by the following method: Step 1: Mix zinc salt, organic ammonium salt and bis(ethylene carbonate) ether and heat to react, thus obtaining an in-situ catalyst; Step 2: Add the purified LA monomer to the in-situ catalyst to react and obtain the product; The mass ratio of zinc salt, organic ammonium salt and bis(ethylene carbonate) ether in step 1 is 1:(10-50):(30-50); the mass ratio of bis(ethylene carbonate) ether in step 1 to LA monomer in step 2 is 1:(30-60). The zinc salt is selected from one of zinc chloride, zinc acetate, and zinc bromide, and the organic ammonium salt is selected from one of tetrabutylammonium chloride, tetrabutylammonium iodide, and tetrabutylammonium bromide.

2. The method for preparing hydrophilic, flexible polyurethane sponge according to claim 1, characterized in that, The mass ratio of the isocyanate, polylactic acid polyol and water added in step one is (40-50): 100: (2-3).

3. The method for preparing the hydrophilic, flexible polyurethane sponge according to claim 1, characterized in that, The mass ratio of the polylactic acid polyol, catalyst, and hydrophilic agent added in step one is 100:(0.2-0.5):(10-15).

4. The method for preparing the hydrophilic, flexible polyurethane sponge according to claim 1, characterized in that, The catalyst mentioned in step one is stannous octoate or triethylenediamine.

5. The method for preparing hydrophilic, flexible polyurethane sponge according to claim 1, characterized in that, The hydrophilic agent mentioned in step one is one of polyethylene glycol-modified polysiloxanes.

6. The method for preparing the hydrophilic, flexible polyurethane sponge according to claim 1, characterized in that, The isocyanate mentioned in step one is selected from one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

7. A hydrophilic, flexible polyurethane sponge, characterized in that, Prepared by the method for preparing hydrophilic, flexible polyurethane foam as described in any one of claims 1-6.

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