Hydrophilic and flexible polyurethane sponge and preparation method thereof

Abstract

The invention belongs to the field of polyurethane materials, and provides a hydrophilic flexible polyurethane sponge preparation method, which comprises: 1, uniformly mixing isocyanate, polylactic acid polyol, a catalyst, a hydrophilic agent and water, and carrying out a reaction at a room temperature to obtain a reaction liquid; step 2, foaming and curing the reaction liquid to obtain the polyurethane sponge material. Polylactic acid polyol with a specific structure is used in the process of preparing the hydrophilic and flexible polyurethane sponge, the polylactic acid polyol contains alcoholic hydroxyl groups and polylactic acid chain segments, the content of the alcoholic hydroxyl groups in molecules of the polylactic acid polyol is appropriate, appropriate cross-linking strength can be provided, and the finally prepared bio-based polyurethane sponge has good flexibility and hydrophilicity and good application prospects; in addition, the preparation method has the advantage of extremely low cost, is suitable for large-scale batch production, and is beneficial to application of the prepared hydrophilic and flexible polyurethane sponge.

Description

Technical Field

[0001] The invention belongs to the field of polyurethane materials, and in particular relates to a hydrophilic and flexible polyurethane sponge and a preparation method thereof. Background Art

[0002] Polyurethane sponge has a foam density of less than 50kg / m 3 The following materials, hydrophilic polyurethane sponge is a polyurethane material with excellent hydrophilic properties. Due to the introduction of hydrophilic groups or segments in its molecular chain, its ability to absorb and retain water is significantly improved. This characteristic makes the hydrophilic polyurethane sponge perform better in environments that need to absorb water quickly and maintain a certain humidity. It can be used in furniture, cosmetic accessories, aquaculture and other fields, and has a broader application prospect.

[0003] Hydrophilic polyurethane sponge is a polyurethane sponge prepared by using hydrophilic monomers as polymerization raw materials. A document discloses a hydrophilic polyurethane foam material, which is prepared by using polymer polyol, isocyanate, foaming agent, catalyst, foam leveling agent, cell opening agent and other substances. However, the polylactic acid polyol used in this method has a single molecular structure and poor molecular flexibility. The polyurethane sponge prepared by using it has poor flexibility. Although it has a certain hydrophilicity, it still has the problem of insufficient hydrophilicity. Summary of the invention

[0004] In order to solve the problem that the existing bio-based polyurethane sponge has poor flexibility and insufficient hydrophilicity, the present invention provides a hydrophilic and flexible polyurethane sponge and a preparation method thereof.

[0005] The preparation method of the hydrophilic, flexible polyurethane sponge comprises the following steps:

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

[0007] Step 2: foaming and aging the reaction solution to obtain the polyurethane sponge material.

[0008] The structural formula of the polylactic acid polyol described in step 1 is as follows:

[0009]

[0010] Among them, 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 1 is (40-50):100:(2-3).

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

[0013] Furthermore, the catalyst in step 1 is stannous octoate or triethylene diamine.

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

[0015] Furthermore, the isocyanate in step 1 is selected from one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

[0016] Furthermore, the polylactic acid polyol described in step 1 is prepared by the following method:

[0017] Step 1, mixing zinc salt, organic ammonium salt and bis(ethylene carbonate) ether and heating them for reaction to obtain an in-situ catalyst;

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

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

[0020] Furthermore, 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 invention also provides a hydrophilic and flexible polyurethane sponge.

[0022] The hydrophilic and flexible polyurethane sponge is prepared by the method for preparing the hydrophilic and flexible polyurethane sponge as described in any one of the above items.

[0023] The beneficial effects brought by the present invention are as follows:

[0024] (1) The present invention uses polylactic acid polyol with a specific structure, a hydrophilic agent and other materials as raw materials to prepare a polyurethane sponge. Since the chain segments contained in the polylactic acid polyol used have good flexibility and the polylactic acid polyol has two hydroxyl groups in its molecular structure, it can provide a suitable cross-linking strength, so that the prepared polyurethane sponge has good flexibility. In addition, due to the coordination of the polylactic acid chain segments of the polylactic acid polyol and the hydrophilic agent, the prepared polyurethane has excellent hydrophilicity.

[0025] (2) The present invention adopts a new catalytic system with high catalytic activity to prepare polylactic acid polyol with high safety at low cost. Using the polylactic acid polyol to prepare polyurethane sponge can reduce the preparation cost of polyurethane sponge, which is beneficial to the promotion and application of polyurethane sponge. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention provides a flow chart of the method for preparing the hydrophilic and flexible polyurethane sponge. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings, but they should not be construed as limiting the applicable scope of the present invention.

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

[0029] See also Figure 1 A method for preparing a hydrophilic, flexible polyurethane sponge, characterized in that it comprises the following steps:

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

[0031] Step 2: foaming and aging the reaction solution to obtain the polyurethane sponge material.

[0032] The structural formula of the polylactic acid polyol described in step 1 is as follows:

[0033]

[0034] Among them, m is 3-20 and n is 3-20.

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

[0036] Example 1

[0037] 1. Preparation of polylactic acid polyol:

[0038] Step 1, 0.5 g of bis(vinyl carbonate) ether, 0.01 g of zinc chloride, and 0.3 g of tetrabutylammonium chloride were mixed, and reacted at 200° C. and 1 MPa for 1 h to obtain an in-situ catalyst;

[0039] Step 2, then adding 18 g of LA monomer to the in-situ catalyst and reacting at 160° C. for 1 h to obtain a product;

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

[0041] 2. Preparation of hydrophilic, flexible polyurethane sponge

[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 liquid; the reaction liquid is foamed and matured at normal pressure for 24h to obtain the polyurethane sponge material.

[0043] Example 2

[0044] 1. Preparation of polylactic acid polyol:

[0045] Step 1, 0.4 g of bis(vinyl carbonate) ether, 0.01 g of zinc acetate, and 0.3 g of dimethylaminopyridine were mixed, and reacted at 200° C. and 1 MPa for 1.5 h to obtain an in-situ catalyst;

[0046] Step 2, then adding 18 g of LA monomer to the in-situ catalyst and reacting at 180° C. for 1 h to obtain a product;

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

[0048] 2. Preparation of hydrophilic, flexible polyurethane sponge

[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 liquid; the reaction liquid is foamed and matured at normal pressure for 24h to obtain the polyurethane sponge material.

[0050] Example 3

[0051] 1. Preparation of polylactic acid polyol:

[0052] Step 1, 0.3 g of 1,4-butanediol diglycidyl ether, 0.01 g of zinc chloride, and 0.3 g of tetrabutylammonium chloride were mixed, and reacted at 200° C. and 1 MPa for 1.5 h to obtain an in-situ catalyst;

[0053] Step 2, then adding 18 g of LA monomer to the in-situ catalyst and reacting at 130° C. for 2 h to obtain a product;

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

[0055] 2. Preparation of hydrophilic, flexible polyurethane sponge

[0056] Take 5g of isophorone diisocyanate, 10g of the above-mentioned polylactic acid polyol, 0.04g of dibutyltin didodecylsulfide, 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] 1. Preparation of polylactic acid polyol:

[0059] Step 1, 0.5 g of diglycidyl ether, 0.01 g of zinc chloride, and 0.5 g of tetrabutylammonium iodide were mixed, and reacted at 200° C. and 1 MPa for 1 h to obtain an in-situ catalyst;

[0060] Step 2, then adding 18 g of LA monomer to the in-situ catalyst and reacting at 160° C. for 2 h to obtain a product;

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

[0062] 2. Preparation of hydrophilic, flexible polyurethane sponge

[0063] Take 4g of hexamethylene diisocyanate, 10g of the above-mentioned 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] 1. Preparation of polylactic acid polyol:

[0066] Step 1, 0.5 g of diglycidyl ether, 0.01 g of zinc bromide, and 0.1 g of tetrabutylammonium bromide were mixed, and reacted at 210° C. and 1 MPa pressure for 1 h to obtain an in-situ catalyst;

[0067] Step 2, then adding 18g of LA monomer to the in-situ catalyst and reacting at 160°C for 1h to obtain a product;

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

[0069] 2. Preparation of hydrophilic, flexible polyurethane sponge

[0070] Take 4.5g toluene 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 0.2g of water, mix them evenly, react at room temperature, and mature for 24h to obtain a hydrophilic sponge.

[0071] Example 6

[0072] 1. Preparation of polylactic acid polyol:

[0073] Step 1, 0.5 g of diglycidyl ether, 0.01 g of zinc bromide, and 0.30 g of tetrabutylammonium iodide were mixed, and reacted at 220° C. and 1 MPa for 2 h to obtain an in-situ catalyst;

[0074] Step 2, then adding 18g of LA monomer to the in-situ catalyst and reacting at 160°C for 1h to obtain a product;

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

[0076] 2. Preparation of hydrophilic, flexible polyurethane sponge

[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 (GSY-2510 of Guangsiyuan Polyurethane Materials Co., Ltd.) 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] 1. Preparation of hydrophilic and flexible polyurethane sponge

[0080] Take 4.5g of diphenylmethane diisocyanate, 10g of polylactic acid polyol (Mingshan Biotechnology Company, 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 liquid; the reaction liquid is foamed and matured at normal pressure for 24h to obtain a hydrophilic, 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] Among them, the water absorption rate is measured with reference to GB / T1034-2008;

[0083] The indentation hardness is tested according to GBT-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 830％ 780％ 810％ 590％ 580％ 620％ 569％ Indentation hardness 1.62 1.67 1.68 1.63 1.66 1.68 1.80

[0086] It can be seen from the above test results that the bio-based polyurethane sponge prepared by the method of the present invention has good hydrophilicity and flexibility. In Comparative Example 1, the existing polylactic acid polyol is used to prepare the polyurethane sponge. Since the polylactic acid polyol chain segment has poor flexibility and hydrophilicity, the polyurethane sponge prepared by using it has relatively poor hydrophilicity and flexibility.

[0087] In addition, the cost of preparing polyurethane sponges using petroleum-based polylactic acid polyols using existing reported technologies is 30 to 39 yuan / kg, while the cost of hydrophilic and flexible polyurethane sponges available on the market is 30 to 35 yuan / kg. The cost of hydrophilic bio-based polyurethanes prepared using the method of the present invention is 25 to 50 yuan / kg, indicating that the method of the present invention can significantly reduce the cost of preparing hydrophilic and flexible polyurethane sponges.

Claims

1. A method for preparing a hydrophilic, flexible polyurethane sponge, characterized in that: The following steps are involved: Step 1: uniformly mix isocyanate, polylactic acid polyol, catalyst, hydrophilic agent and water, and react at room temperature to obtain a reaction solution; Step 2: foaming and aging the reaction solution to obtain the polyurethane sponge material. The structural formula of the polylactic acid polyol described in step 1 is as follows: Among them, m is 3-20 and n is 3-20.

2. The method for preparing a 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 1 is (40-50):100:(2-3).

3. The method for preparing a 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 1 is 100:(0.2-0.5):(10-15).

4. The method for preparing a hydrophilic, flexible polyurethane sponge according to claim 1, characterized in that: The catalyst in step 1 is stannous octoate or triethylene diamine.

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

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

7. The method for preparing a hydrophilic, flexible polyurethane sponge according to claim 1, characterized in that: The polylactic acid polyol described in step 1 is prepared by the following method: Step 1, mixing zinc salt, organic ammonium salt and bis(ethylene carbonate) ether and heating them for reaction to obtain an in-situ catalyst; Step 2: adding the purified LA monomer to the in-situ catalyst to react and obtain a product.

8. The method for preparing a hydrophilic, flexible polyurethane sponge according to claim 7, characterized in that: The mass ratio of the zinc salt, the organic ammonium salt and the bis(ethylene carbonate) ether in step 1 is 1:(10-50):(30-50).

9. The method for preparing a hydrophilic, flexible polyurethane sponge according to claim 7, characterized in that: The mass ratio of the bis(ethylene carbonate) ether in step 1 to the LA monomer in step 2 is 1:(30-60).

10. A hydrophilic, flexible polyurethane sponge, characterized in that: The hydrophilic and flexible polyurethane sponge is prepared by the method for preparing the hydrophilic and flexible polyurethane sponge as described in any one of claims 1 to 9.

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