Isocyanate modified chain extension polyol as well as preparation method and application thereof

Abstract

The invention discloses an isocyanate modified chain extension polyol, a preparation method and an application. The preparation method comprises the following steps: step 1, carrying out dehydration treatment on a polyol raw material; 2, the dehydrated polyol raw material is put into a microwave reaction kettle, an anti-explosion agent is added for mechanical stirring, and the anti-explosion agent is one or more of phosphoric acid and trifluoromethanesulfonic acid; 3, isocyanate is added into the microwave reaction kettle, and the microwave reaction kettle is started for heat preservation; and step 4, filtering a product in the microwave reaction kettle to prepare the isocyanate modified chain extension polyol. The anti-explosion agent is added, so that the molecular weight of the prepared isocyanate modified chain extension polyol is narrower, the reaction is effectively prevented from generating implosion, and the reaction is more stable. The prepared isocyanate modified chain extension polyol is used for preparation of a PU pouring sealant, can reduce the highest reaction temperature, is suitable for preparation of electronic components sensitive to temperature, and can improve the elongation at break of the PU pouring sealant.

Description

Technical Field

[0001] The present invention relates to the technical field of material preparation, and in particular to an isocyanate-modified chain-extended polyol, a preparation method and an application thereof. Background Art

[0002] At present, the operational requirements and performance requirements for various functional polyurethane products are getting higher and higher, and many monomer small molecule polyols can no longer meet the needs of formula design. The microwave method can efficiently synthesize isocyanate chain-extended polyols with narrower molecular weight distribution, which can meet the direction of many applications that are sensitive to exothermic heat (such as lithium batteries, core carbonization problems of large PU foams, and potting problems of heat-sensitive electronic components). The Chinese invention patent application with publication number CN 200910135824.9: A microwave synthesis method for polyester polyols for polyurethane soles, the patent also points out that microwave synthesis of polyester polyols has the advantages of low energy consumption and good product quality. However, the reaction between isocyanate and alcohol hydroxyl is an exothermic reaction, and there is a risk of violent polymerization during the microwave synthesis process. Summary of the invention

[0003] Purpose of the invention: In view of the above shortcomings, the present invention provides an isocyanate-modified chain-extended polyol, a preparation method and application thereof.

[0004] Technical solution: To solve the above problems, the present invention adopts an isocyanate-modified chain-extended polyol having the molecular formula The molecular weight is 400-1100, the functionality is 2, and the viscosity is 1500-8300 Mpa.s, wherein R is an alkane group and n is in the range of 1-3.

[0005] The present invention also provides a method for preparing the above-mentioned isocyanate-modified chain-extended polyol, comprising the following steps:

[0006] Step 1, dehydrating the polyol raw material;

[0007] Step 2, putting the dehydrated polyol raw material into a microwave reactor, and adding an anti-riot agent for mechanical stirring, wherein the anti-riot agent is at least one of phosphoric acid and trifluoromethanesulfonic acid;

[0008] Step 3, adding isocyanate into the microwave reactor and opening the microwave reactor for heat preservation;

[0009] Step 4: Filter the product in the microwave reactor to obtain isocyanate-modified extended chain polyol. Further, the added mass of the anti-riot agent is 0.02%-0.06% of the mass of the dehydrated polyol raw material.

[0010] Further, the dehydrated polyol is expected to have a water content of less than 500 ppm.

[0011] Furthermore, the polyol raw material and isocyanate are added so that the ratio of the NCO mole number to the hydroxyl mole number is 1:2.

[0012] Furthermore, the isocyanate is at least one of TDI, MDI and IPDI.

[0013] Furthermore, the hydroxyl value of the polyol raw material ranges from 270 to 1255 mgKOH / g, and the functionality is 2 to 3.

[0014] Furthermore, the mechanical stirring setting temperature is 60-65°C; the insulation temperature is 60-65°C, and the insulation time is 1-3h.

[0015] Furthermore, the microwave frequency of the microwave reactor is 2450±50 MHz, and the power of a single microwave tube is 50 to 500 watts.

[0016] The present invention also provides application of the isocyanate-modified chain-extended polyol in the preparation of PU potting adhesive.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) by adding an anti-explosion agent, the molecular weight of the obtained isocyanate-modified extended chain polyol is made narrower, and the reaction is effectively prevented from undergoing polymerization, making the reaction more stable; (2) the obtained isocyanate-modified extended chain polyol is used in the preparation of PU potting adhesive, which can reduce the maximum reaction temperature and is suitable for the preparation of temperature-sensitive electronic components, and can increase the elongation at break of the obtained PU potting adhesive and improve the toughness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the GPC chart of the isocyanate-modified chain-extended polyol obtained in Example 1;

[0019] Figure 2 This is the GPC chart of the isocyanate-modified chain-extended polyol obtained in Example 2;

[0020] Figure 3 This is the GPC chart of the isocyanate-modified chain-extended polyol obtained in Example 3;

[0021] Figure 4 This is the GPC chart of the isocyanate-modified chain-extended polyol obtained in Example 4;

[0022] Figure 5 This is the GPC chart of the isocyanate-modified extended chain polyol prepared in Comparative Example 1. DETAILED DESCRIPTION

[0023] Embodiment 1

[0024] The preparation method of an isocyanate-modified chain-extended polyol in this embodiment comprises the following steps:

[0025] Step 1: Dehydrate the polyol raw material to make the water content of the polyol after dehydration less than 500 ppm. The polyol raw material used in this embodiment is NJ-204 (400 molecular weight diol from Ningwu, Jurong, Zhenjiang, Jiangsu), and its hydroxyl value is 270-290 mgKOH / g.

[0026] Step 2: 50 parts by mass of the dehydrated polyol raw material are put into a microwave reactor, and 0.06% by mass of trifluoromethanesulfonic acid, i.e. 0.03 parts by mass of trifluoromethanesulfonic acid, is added, and mechanical stirring is performed at 65° C.

[0027] Step 3, add 15.7 parts by mass of isocyanate to the microwave reactor while stirring and turn on the microwave reactor to keep warm at 65 ° C for 3 hours. The isocyanate used in this embodiment is MDI-50 (Yantai Wanhua 2,4-diphenylmethane diisocyanate). The NCO index of the polyol and isocyanate added to the reaction raw materials is 50, that is, the ratio of the number of NCO molecules to the number of hydroxyl groups in the two raw materials is 1:2. The microwave frequency of the microwave reactor is 2450 ± 50 MHz, and the power of a single microwave tube is 50 to 500 watts.

[0028] Step 4: Filter the product in the microwave reactor to obtain isocyanate-modified chain-extended polyol. The molecular formula of the obtained isocyanate-modified chain-extended polyol is as follows:

[0029]

[0030] The molecular weight is 1000-1050 and the viscosity is about 1500-2000Mpa.s.

[0031] Embodiment 2

[0032] The preparation method of an isocyanate-modified chain-extended polyol in this embodiment comprises the following steps:

[0033] Step 1: Dehydrate the polyol raw material to make the moisture content of the dehydrated polyol raw material less than 500 ppm. The polyol used in this embodiment is dipropylene glycol, and its hydroxyl value is 835-845 mgKOH / g.

[0034] Step 2: 50 parts by mass of the dehydrated polyol is put into a microwave reaction kettle, and 0.02% by mass of trifluoromethanesulfonic acid, i.e. 0.01 parts by mass of trifluoromethanesulfonic acid, is added, and mechanical stirring is performed at 60°C.

[0035] Step 3, add 47 parts by mass of isocyanate to the microwave reactor while stirring and turn on the microwave reactor to keep warm at 60°C for 1 hour. The isocyanate used in this embodiment is MDI-50 (Yantai Wanhua 2,4-diphenylmethane diisocyanate). The NCO index of the polyol and isocyanate added to the reaction raw materials is 50. The microwave frequency of the microwave reactor is 2450±50MHz, and the power of a single microwave tube is 50 to 500 watts.

[0036] Step 4: Filter the product in the microwave reactor to obtain isocyanate-modified chain-extended polyol. The molecular formula of the obtained isocyanate-modified chain-extended polyol is as follows:

[0037]

[0038] The molecular weight is 500-520 and the viscosity is about 8000-8300Mpa.s.

[0039] Embodiment 3

[0040] The preparation method of an isocyanate-modified chain-extended polyol in this embodiment comprises the following steps:

[0041] Step 1: Dehydrate the polyol raw material to make the moisture content of the dehydrated polyol raw material less than 500 ppm. The polyol used in this embodiment is 1,4-butanediol, and its hydroxyl value is 1245-1255 mgKOH / g.

[0042] Step 2: 50 parts by mass of the dehydrated polyol raw material is put into a microwave reactor, and 0.04% by mass of trifluoromethanesulfonic acid, i.e. 0.02 parts by mass of trifluoromethanesulfonic acid, is added, and mechanical stirring is performed at 60° C.

[0043] Step 3, add 70 parts by mass of isocyanate to the microwave reactor while stirring and turn on the microwave reactor to keep warm at 60°C for 2 hours. The isocyanate used in this embodiment is MDI-50 (Yantai Wanhua 2,4-diphenylmethane diisocyanate). The NCO index of the polyol raw material and isocyanate added to the reaction raw material is 50. The microwave frequency of the microwave reactor is 2450±50MHz, and the power of a single microwave tube is 50 to 500 watts.

[0044] Step 4: Filter the product in the microwave reactor to obtain isocyanate-modified chain-extended polyol. The molecular formula of the obtained isocyanate-modified chain-extended polyol is as follows:

[0045]

[0046] The molecular weight is 400-430 and the viscosity is about 3000-3500Mpa.s.

[0047] Embodiment 4

[0048] The preparation method of an isocyanate-modified chain-extended polyol in this embodiment comprises the following steps:

[0049] Step 1: Dehydrate the polyol raw material to make the moisture content of the dehydrated polyol raw material less than 500 ppm. The polyol used in this embodiment is 1,4-butanediol, and its hydroxyl value is 1245-1255 mgKOH / g.

[0050] Step 2: 50 parts by weight of the dehydrated polyol raw material is put into a microwave reaction kettle, and 0.04% by weight of trifluoromethanesulfonic acid, that is, 0.02 parts by weight of phosphoric acid, based on the weight of the polyol raw material is added, and mechanical stirring is performed at 60° C.

[0051] Step 3, add 70 parts by mass of isocyanate to the microwave reactor while stirring and turn on the microwave reactor to keep warm at 60°C for 2 hours. The isocyanate used in this embodiment is MDI-50 (Yantai Wanhua 2,4-diphenylmethane diisocyanate). The NCO index of the polyol and isocyanate added to the reaction raw materials is 50. The microwave frequency of the microwave reactor is 2450±50MHz, and the power of a single microwave tube is 50 to 500 watts.

[0052] Step 4: Filter the product in the microwave reactor to obtain isocyanate-modified chain-extended polyol. The molecular formula of the obtained isocyanate-modified chain-extended polyol is as follows:

[0053]

[0054] The molecular weight is 400-420 and the viscosity is about 2800-3100Mpa.s.

[0055] Comparative Example 1

[0056] The preparation method of an isocyanate-modified chain-extended polyol in this embodiment comprises the following steps:

[0057] Step 1: Dehydrate the polyol raw material to make the moisture content of the dehydrated polyol raw material less than 500 ppm. The polyol used in this embodiment is NJ-204 (400 molecular weight diol from Ningwu, Jurong, Zhenjiang, Jiangsu), and its hydroxyl value is 270-290 mgKOH / g.

[0058] Step 2: 50 parts by weight of the dehydrated polyol raw material is put into a microwave reaction kettle and mechanically stirred at 65° C.

[0059] Step 3, add 15.7 parts by mass of isocyanate to the microwave reactor while stirring and turn on the microwave reactor to keep warm at 65°C for 3 hours. The isocyanate used in this embodiment is MDI-50 (Yantai Wanhua 2,4-diphenylmethane diisocyanate). The NCO index of the polyol and isocyanate added to the reaction raw materials is 50. The microwave frequency of the microwave reactor is 2450±50MHz, and the power of a single microwave tube is 50 to 500 watts.

[0060] Step 4: Filter the product in the microwave reactor to obtain isocyanate-modified chain-extended polyol. The molecular formula of the obtained isocyanate-modified chain-extended polyol is as follows:

[0061]

[0062] The molecular weight is 800-1060 and the viscosity is about 1500-2000Mpa.s.

[0063] Results Analysis

[0064] like Figures 1 to 5 As shown, the first peak in the figure is the product peak. Figure 1-Figure 4 The peak is sharper, the peak width is narrower, and no tailing peak appears, indicating that the molecular weight of the obtained product is narrower, and no violent polymerization occurs in the reaction, proving that the addition of the anti-riot agent has a corresponding effect. At the same time, the peak of Example 4 is sharper, and the molecular weight of the obtained product is narrower, indicating that phosphoric acid is better than trifluoromethanesulfonic acid, and is more conducive to narrowing the molecular weight distribution of the product and avoiding violent polymerization in the reaction.

[0065] In order to further analyze the effect of the obtained product on the viscosity of the product when it is used for the subsequent preparation of potting PU glue, the product obtained in each example was mixed with heavy calcium powder in a ratio of 1:1, and the viscosity of the obtained mixed product was measured. The results are as follows:

[0066]

[0067] Table 1

[0068] From the data in the above table, it can be seen that the isocyanate-modified extended chain polyols prepared in Examples 1, 3, and 4 have lower viscosity after mixing with heavy calcium powder, which is beneficial to the dispensing operation of subsequent products. In Example 2, since dipropylene glycol is used as the polyol material, although the molecular weight of the prepared product is relatively narrow, the side chains contained in its structure have a certain influence on the viscosity of the product, so the viscosity of the product is relatively large, and the polyol can be selected according to actual needs to obtain the desired effect. The viscosity value of the product obtained in Example 1 is the same as that of the comparative example 1, but since the molecular weight of the product obtained in Example 1 is narrower, the viscosity obtained after Example 1 is mixed with heavy calcium powder is also lower, indicating that the isocyanate-modified extended chain polyol with a narrower molecular weight prepared by the present invention is more suitable for the subsequent preparation of PU glue and has better performance.

[0069] Embodiment 5

[0070] The present invention also provides an application of the prepared isocyanate-modified extended chain polyol in the preparation of PU potting glue, wherein the isocyanate-modified extended chain polyol, dehydrated castor oil, and 1250 mesh heavy calcium powder prepared in Examples 1-4 and Comparative Example 1 are mixed in a mass ratio of 10:90:100 for vacuum degassing to prepare component A, and then component A is mixed with PM200 in a mass ratio of 100:20 and then cured to prepare PU potting glue. The potting glues prepared in Examples 1-4 and Comparative Example 1 are numbered as products 1-5 in sequence.

[0071] As a comparison, the isocyanate-modified extended chain polyol was replaced with dipropylene glycol and 1,4-butanediol to prepare PU potting adhesive. Products 6 and 7 were obtained respectively. The elongation at break and the highest temperature during preparation of products 1-7 were measured, and the results are shown in the following table:

[0072] Elongation at break (%) Maximum reaction temperature of materials (℃) Product 1 194 36 Product 2 164 39 Product 3 170 38 Product 4 203 37 Product 5 133 37 Product 6 102 98 Product 7 108 106

[0073] Table 2

[0074] From the data in the table, it can be seen that the maximum reaction temperature of products 6 and 7 prepared using non-chain-extended polyols reaches 98 and 106°C, which is significantly higher than the reaction temperature prepared using isocyanate-modified extended polyols, and cannot be used in the preparation of temperature-sensitive electronic components, such as the electronic potting glue industry, which requires the maximum reaction temperature of the material not to exceed 50°C. Chain-extended polyols can be used to prepare materials that have more stringent and sensitive temperature requirements. Product 5 prepared using isocyanate-modified extended polyols prepared in Comparative Example 1 has a higher elongation at break than products 6 and 7, but is significantly lower than products 1-4, indicating that anti-riot polymerization treatment is beneficial to improving the elongation at break of the material. And by comparing product 3 with product 4, it can be seen that compared with trifluoromethanesulfonic acid, phosphoric acid as an anti-riot agent is also more conducive to improving the elongation at break of the material.

Claims

1. An isocyanate-modified extended chain polyol, characterized in that: The molecular formula is The molecular weight is 400-1100, the functionality is 2, and the viscosity is 1500-8300 Mpa.s, wherein R is an alkane group and n is in the range of 1-3.

2. A method for preparing the isocyanate-modified chain-extended polyol according to claim 1, characterized in that: The following steps are involved: Step 1, dehydrating the polyol raw material; Step 2, putting the dehydrated polyol raw material into a microwave reactor, and adding an anti-riot agent for mechanical stirring, wherein the anti-riot agent is at least one of phosphoric acid and trifluoromethanesulfonic acid; Step 3, adding isocyanate into the microwave reactor and opening the microwave reactor for heat preservation; Step 4: Filter the product in the microwave reactor to obtain isocyanate-modified extended chain polyol.

3. The method for preparing an isocyanate-modified chain-extended polyol according to claim 2, characterized in that: The added mass of the anti-riot agent is 0.02%-0.06% of the mass of the dehydrated polyol raw material.

4. The method for preparing an isocyanate-modified chain-extended polyol according to claim 2, characterized in that: The moisture content of the dehydrated polyol raw material is less than 500 ppm.

5. The method for preparing an isocyanate-modified chain-extended polyol according to claim 2, characterized in that: The polyol raw material and isocyanate are added so that the ratio of the NCO mole number to the hydroxyl mole number is 1:

2.

6. The method for preparing an isocyanate-modified chain-extended polyol according to claim 2, characterized in that: The isocyanate is at least one of TDI, MDI and IPDI.

7. The method for preparing an isocyanate-modified chain-extended polyol according to claim 2, characterized in that: The hydroxyl value of the polyol raw material ranges from 270 to 1255 mgKOH / g, and the functionality is 2 to 3.

8. The method for preparing an isocyanate-modified chain-extended polyol according to claim 2, characterized in that: The mechanical stirring setting temperature is 60-65° C.; the insulation temperature is 60-65° C., and the insulation time is 1-3 hours.

9. The method for preparing an isocyanate-modified chain-extended polyol according to claim 2, characterized in that: The microwave frequency of the microwave reaction kettle is 2450±50MHz, and the power of a single microwave tube is 50-500W.

10. Use of the isocyanate-modified chain-extended polyol according to claim 1 in the preparation of PU potting adhesive.

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