High-foaming polyurethane adhesive for metal sandwich plate and preparation method of high-foaming polyurethane adhesive

Abstract

The invention relates to the technical field of polyurethane adhesives, in particular to a high-foaming polyurethane adhesive for a metal sandwich plate and a preparation method of the high-foaming polyurethane adhesive, and the high-foaming polyurethane adhesive is prepared from a polyol mixture and isocyanate according to the mass ratio of 5: (1.75-2.25); the polyol mixture is at least prepared from the following raw materials in parts by weight: 156 to 176 parts of castor oil, 260 to 280 parts of polyether polyol A with a hydroxyl value of 200 to 400 mgKOH / g, 85 to 95 parts of polyether polyol B with a hydroxyl value of 40 to 100 mgKOH / g, 0.8 to 1.2 parts of a wetting agent, 2.8 to 3.2 parts of dibutyltin dilaurate, 0.3 to 0.5 part of triethylene diamine, 660 to 700 parts of filler, 5 to 7 parts of fumed silica, 3.5 to 4.5 parts of glycerol and 7 to 9 parts of a foaming agent. The product provided by the invention meets the requirement of immediately cutting and applying after actual hot pressing of constructional engineering is completed.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane adhesives, in particular to a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. Background Art

[0002] Metal sandwich panels are used in construction projects. In actual use, the panels are required to be cut immediately after hot pressing and cut into the required size. In the past, in order to test the material breakage rate of the plate, it was always done after the plate was cooled or cured for one day. However, as the cooling or curing time is extended, the material breakage rate of the plate will theoretically increase. Therefore, according to the existing testing standards, it cannot be determined whether the material breakage rate of the plate after hot pressing can meet the actual use requirements. Chinese patent (Authorization No. CN111454686B) discloses a high-foaming two-component polyurethane adhesive and its preparation method. The adhesive can meet the sandwich sandwich structure composite application requirements of color steel plate (cement fiber cloth)-rock wool-color steel plate (cement fiber cloth). The material breakage rate of the board after curing for 1 day is relatively high. However, the material breakage rate of the board was tested immediately after the completion of hot pressing. It was found that the material breakage rate decreased and white skin appeared. The Chinese patent (Authorization No. CN107556962B) discloses a two-component polyurethane adhesive for construction and its preparation method. It uses polyether polyol and chain extender in component A to form a three-dimensional network structure with a high degree of cross-linking, and uses water as a foaming agent to produce a foamed structure, allowing the adhesive to solidify deep inside the rock wool and improve the strength of the rock wool body. However, it still cannot meet the needs of cutting applications immediately after the actual hot pressing of construction projects. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a high-foaming polyurethane glue for metal sandwich panels. By optimizing the product formula system, comprehensively regulating the compatibility of the polyol-isocyanate, catalyst and wetting agent in the system, and cooperating with other raw materials, the provided product can be sprayed into the middle of the metal sandwich panel and immediately subjected to a material breakage test after hot pressing. It still has a high material breakage rate and will not appear white skin. It meets the needs of immediate cutting applications after the actual hot pressing of construction projects.

[0004] On the one hand, the present invention provides a high-foaming polyurethane glue for metal sandwich panels, which is composed of a polyol mixture and isocyanate in a mass ratio of 5: (1.75-2.25); in parts by weight, the raw materials for preparing the polyol mixture include at least: 156-176 parts of castor oil, and polyether polyol A with a hydroxyl value of 200-400 mgKOH / g. 260-280 parts, polyether polyol B with hydroxyl value 40-100mgKOH / g 85-95 parts, wetting agent 0.8-1.2 parts, dibutyltin dilaurate 2.8-3.2 parts, triethylenediamine 0.3-0.5 parts, filler 660-700 parts, fumed silica 5-7 parts, glycerol 3.5-4.5 parts, foaming agent 7-9 parts, foam leveling agent 2.8-3.2 parts, defoaming agent 0.8-1.2 parts.

[0005] In one embodiment, the polyether polyol A has a hydroxyl value of 250-300 mgKOH / g.

[0006] In one embodiment, the polyether polyol A has a hydroxyl value of 270-290 mgKOH / g.

[0007] In one embodiment, the viscosity of the polyether polyol A at 25° C. is 50-120 mPa·s.

[0008] In one embodiment, the viscosity of the polyether polyol A at 25° C. is 60-80 mPa·s.

[0009] In one embodiment, the polyether polyol A is of model DDL-400, has a hydroxyl value of 270-290 mgKOH / g, and a viscosity of 60-80 mPa·s at 25° C., and is sourced from Zibo Dexin Federal Chemical Industry Co., Ltd.

[0010] In one embodiment, the polyether polyol B has a hydroxyl value of 50-60 mgKOH / g.

[0011] In one embodiment, the hydroxyl value of the polyether polyol B is 56±1.5 mgKOH / g.

[0012] In one embodiment, the viscosity of the polyether polyol B at 25° C. is ≤700 mPa·s.

[0013] In one embodiment, the polyether polyol B is DEP-560D, has a hydroxyl value of 56±1.5 mgKOH / g, and a viscosity of ≤700 mPa·s at 25°C, and is sourced from Zibo Dexin Federal Chemical Industry Co., Ltd. In one embodiment, the wetting agent is selected from at least one of BYK-W 966, BYK-9076, BYK-9077, and BYK-202.

[0014] In one embodiment, the wetting agent is BYK-202.

[0015] The present invention mainly aims at optimizing the problems existing in the actual production and application process after the existing polyurethane foam is used in the bonding of the three-layer sandwich structure of color steel plate-rock wool-color steel plate (referred to as metal sandwich plate). In the actual use of metal sandwich plates in construction projects, the plates are required to be cut and used immediately after hot pressing. The material breakage rate cannot meet the actual use requirements, and the white skin phenomenon occurs. In the early stage of the present invention, an attempt was made to improve the curing efficiency and overcome the white skin phenomenon by increasing the amount of catalyst added. However, the obtained product not only failed to effectively solve the white skin problem, but also resulted in a decrease in flat tensile strength. Through further experimental research, it was found that the comprehensive performance of polyurethane foam obtained by using a single low hydroxyl value polyether polyol or medium hydroxyl value polyether polyol decreased in the actual application process. During the optimization of the polyether polyol system, it was unexpectedly found that polyether polyol A with a hydroxyl value of 200-400 mgKOH / g and a viscosity of 50-120mPa·s at 25°C was The hydroxyl value is 40-100mgKOH / g, and the viscosity at 25℃ is ≤700 The mass ratio of polyether polyol B in mPa·s is (2.8-3.2): 1. Introducing a foam system and adding 0.8-1.2 parts of wetting agent ensures that the obtained polyurethane foam has a suitable viscosity and a low density to obtain higher flat tensile strength and material breakage rate, effectively avoiding the problem of material breakage. However, other foams prepared by combining polyether polyol A and polyether polyol B cannot achieve the above effects.

[0016] In one embodiment, the filler comprises at least calcium carbonate, and the particle size of the calcium carbonate is 800-1000 mesh.

[0017] In one embodiment, the particle size of the calcium carbonate is 800 mesh, the manufacturer is Changzhou Lehuan Trading Co., Ltd., and the brand is: 800 mesh heavy calcium carbonate 25KG.

[0018] In one embodiment, the BET specific surface area of ​​the fumed silica is 150-250 m² / g, and the model of the fumed silica is preferably AEROSIL 200.

[0019] In one embodiment, the blowing agent is water.

[0020] In one embodiment, the foam leveling agent is selected from at least one of Maihao BL-3002, BL-8100, BL-8762 and Longsheng Sihai SH-493.

[0021] In one embodiment, the foam leveling agent is Maihao BL-3002.

[0022] The present invention uses water as a foaming agent and ensures the foaming rate, foaming uniformity and composite strength of the foamed adhesive used in the metal sandwich panel by comprehensively regulating the amount of the foaming agent added in the system and the use of glycerin and a foaming agent.

[0023] In one embodiment, the defoaming agent is selected from at least one of Sixin Technology SX-63, Hongtai X-2521, Ziyi Chemical ZY-1811, and BYK BYK-A506.

[0024] In one embodiment, the defoaming agent is of the type SX-63 produced by Sixin Technology.

[0025] In one embodiment, the viscosity of the isocyanate at 25° C. is 100-300 mPa·s.

[0026] In one embodiment, the viscosity of the isocyanate at 25° C. is 150-250 mPa·s.

[0027] In one embodiment, the isocyanate has an isocyanate content (—NCO) of 20-40 wt %.

[0028] In one embodiment, the isocyanate has an isocyanate content (—NCO) of 30.5-32.0 wt %.

[0029] In one embodiment, the isocyanate is polymeric MDI, and the model of the polymeric MDI is preferably Wanhua PM200.

[0030] As a preferred technical solution, the mass ratio of the polyol mixture to the isocyanate is 5:2.

[0031] Furthermore, based on matching the polyol mixture in the system with a polymeric MDI having an isocyanate content (-NCO) of 20-40wt% and a viscosity of 100-300 mPa·s at 25°C, the amount of catalyst added to the system is further regulated to balance the reactivity of the polyol mixture with the isocyanate and the foaming reaction rate, thereby avoiding problems such as excessive density caused by excessive gelation and foam collapse caused by excessive foaming.

[0032] On the other hand, the present invention provides a method for preparing high-foaming polyurethane glue for metal sandwich panels, which at least includes the following steps: add castor oil, polyether polyol A, polyether polyol B, glycerin, fumed silica and wetting agent into a container in parts by weight, stir and mix at 1000-1500r / min for 10-30min; add filler, and mix at 1000-1500r / min. Stir and mix at 1000-1500r / min for 60-90min; add dibutyltin dilaurate and triethylenediamine, stir and mix at 1000-1500r / min for 10-30min; add foaming agent, defoaming agent and foaming agent, stir and mix at 1000-1500r / min for 10-30min to obtain a polyol mixture; when used, blend the polyol mixture and isocyanate before use.

[0033] The polyurethane adhesive provided by the present invention meets the application requirements of spray guns by comprehensively optimizing the product formula system and coordinating process control. The product has excellent operability and is easy to realize large-scale industrial production and application.

[0034] Beneficial effects 1. The present invention provides a high-foaming polyurethane glue for metal sandwich panels. By optimizing the product formula system, comprehensively regulating the compatibility of the polyol-isocyanate, catalyst and wetting agent in the system, and coordinating with other raw materials, the provided product can be sprayed into the middle of the metal sandwich panel and immediately subjected to a material breakage test after hot pressing. It still has a high material breakage rate, and no white skin phenomenon will occur, meeting the needs of immediate cutting applications after the actual hot pressing of construction projects.

[0035] 2. The present invention combines polyether polyol A with a hydroxyl value of 200-400 mgKOH / g and a viscosity at 25°C of 50-120mPa·s and a polyether polyol A with a hydroxyl value of 40-100 mgKOH / g and a viscosity at 25°C of ≤700 The mass ratio of polyether polyol B in mPa·s is (2.8-3.2): 1. Introduce the foam system and add 0.8-1.2 parts of wetting agent to ensure that the obtained polyurethane foam has appropriate viscosity and low density to obtain higher flat tensile strength and material breakage rate, effectively avoiding the problem of material breakage.

[0036] 3. Based on the polyol mixture in the system matching the polymeric MDI with an isocyanate content (-NCO) of 20-40wt% and a viscosity of 100-300 mPa·s at 25°C, the amount of catalyst added in the system is further controlled to balance the reactivity of the polyol mixture and isocyanate and the foaming reaction rate, thereby avoiding problems such as excessive density caused by too rapid gelation and foaming causing collapse.

[0037] 4. The present invention uses water as the foaming agent, and through comprehensive regulation of the amount of the foaming agent added in the system and the use of glycerin and a uniform foaming agent, ensures the foaming rate, foaming uniformity and composite strength of the foamed adhesive used in the metal sandwich panel.

[0038] 5. The polyurethane adhesive provided by the present invention meets the application requirements of spray guns through comprehensive optimization of the product formula system and process control. The product has excellent operability and is easy to realize large-scale industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the material breaking effect diagram of Example 1.

[0040] Figure 2 This is the material breaking effect diagram of Example 2.

[0041] Figure 3 This is the material breaking effect diagram of Example 3.

[0042] Figure 4 This is the material breaking effect diagram of comparative example 1.

[0043] Figure 5 This is the material breaking effect diagram of comparative example 2.

[0044] Figure 6 This is the material breaking effect diagram of comparative example 3.

[0045] Figure 7 This is the material breaking effect diagram of comparative example 4.

[0046] Figure 8 This is the material breaking effect diagram of comparative example 5.

[0047] Figure 9 This is the effect diagram of the material breaking of comparative example 6.

[0048] Figure 10 This is the material breaking effect diagram of comparative example 7.

[0049] Figure 11 This is the material breaking effect diagram of comparative example 8.

[0050] Figure 12 This is the material breaking effect diagram of comparative example 9.

[0051] Figure 13 This is the material breaking effect diagram of comparative example 10.

[0052] Figure 14 This is the material breaking effect diagram of comparative example 11.

[0053] Figure 15 This is the material breaking effect diagram of comparative example 12.

[0054] Figure 16 This is the material breaking effect diagram of comparative example 13. DETAILED DESCRIPTION

[0055] Examples 1-3 Examples 1-3 of the present invention provide a high-foaming polyurethane adhesive for metal sandwich panels, which is composed of a polyol mixture and an isocyanate in a mass ratio of 5:2; in parts by weight, the raw materials for preparing the polyol mixture are shown in Table 1, and the isocyanate is polymeric MDI (Wanhua PM200).

[0056] Table 1

[0057] On the other hand, embodiments 1-3 of the present invention provide a method for preparing high-foaming polyurethane glue for metal sandwich panels, which includes the following steps: add castor oil, polyether polyol A, polyether polyol B, glycerin, fumed silica and wetting agent into a container in parts by weight, stir and mix at 1300r / min for 15min; add filler, and mix at 1300r / min. Stir and mix for 70 minutes under the condition of 1300r / min; add dibutyltin dilaurate and triethylenediamine, stir and mix for 15min at 1300r / min; add a foaming agent, defoaming agent and foaming agent, stir and mix at 1300r / min for 15min to obtain a polyol mixture; when used, blend the polyol mixture and isocyanate before use.

[0058] Comparative Example 1 Comparative Example 1 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 360 parts by weight of Dexin Federal DMN500 (hydroxyl value of 335±10 mgKOH / g and viscosity of 260-380 mPa·s at 25°C).

[0059] Comparative Example 2 Comparative Example 2 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 360 parts by weight of Dexin Federal DEP-560D.

[0060] Comparative Example 3 Comparative Example 3 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 360 parts by weight of Dexin Federal DDL-400.

[0061] Comparative Example 4 Comparative Example 4 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 270 parts by weight of Dexin Federal DMN500 and 90 parts by weight of Dexin Federal DEP-560D.

[0062] Comparative Example 5 Comparative Example 5 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 260 parts by weight of Dexin Federal DMN500 and 100 parts by weight of Dexin Federal DDL-400.

[0063] Comparative Example 6 Comparative Example 6 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 300 parts by weight of Dexin Federal DDL-400 and 60 parts by weight of Dexin Federal DEP-560D.

[0064] Comparative Example 7 Comparative Example 7 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 240 parts by weight of Dexin Federal DDL-400 and 120 parts by weight of Dexin Federal DEP-560D.

[0065] Comparative Example 8 Comparative Example 8 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that 270 parts by weight of polyether polyol A and 90 parts by weight of polyether polyol B are replaced by 360 parts by weight of Dexin Federal DMN500, and 0.4 parts by weight of triethylene diamine are replaced by 0.8 parts by weight of triethylene diamine.

[0066] Comparative Example 9 Comparative Example 9 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. Its specific implementation method is the same as that of Example 1, except that the weight portion of the wetting agent is 0.

[0067] Comparative Example 10 Comparative Example 10 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the weight portion of the wetting agent is 2.

[0068] Comparative Example 11 Comparative Example 11 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. Its specific implementation method is the same as that of Example 1, except that the weight portion of the wetting agent is 0.5.

[0069] Comparative Example 12 Comparative Example 12 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. Its specific implementation method is the same as that of Example 1, except that the 3 parts of dibutyltin dilaurate and 0.4 parts of triethylenediamine are replaced by 3.5 parts of dibutyltin dilaurate and 0.8 parts of triethylenediamine.

[0070] Comparative Example 13 Comparative Example 13 of the present invention provides a high-foaming polyurethane adhesive for metal sandwich panels and a preparation method thereof. Its specific implementation method is the same as that of Example 1, except that the 3 parts of dibutyltin dilaurate and 0.4 parts of triethylenediamine are replaced by 2.2 parts of dibutyltin dilaurate and 0.2 parts of triethylenediamine.

[0071] Performance Testing 1. Polyol Mixture Viscosity of the Polyol Mixture: The polyol mixtures in the Examples and Comparative Examples were tested using a viscometer (viscometer model: BROOKFIELD DV2TRVTJ0, No. 4 rotor, 10 rpm, 25° C.). The test results are shown in Table 2.

[0072] 2. Density of polyol mixture: The polyol mixtures of Examples 1-3 and Comparative Examples 1-13 were placed in a 50 mL (v) density cup. The cup was gently tapped while the liquid was added to remove bubbles. The mass (m) of the polyol mixture was then weighed. The density (ρ) of the polyol mixture was calculated according to the density formula ρ = m / v. The results are shown in Table 2.

[0073] 3. Material breaking effect: After the polyol mixture and isocyanate in the examples and comparative examples are mixed evenly (mixing time is 20s), the mixed colloid is evenly applied to the surface of the color steel plate using a scraper (the amount of glue applied is 200g / m 2 ), hot pressing was performed at 45°C for 5 minutes to prepare a sandwich structure of color steel plate-rock wool-color steel plate. After the hot pressing was completed, the plate was taken out and the color steel plate and rock wool were immediately subjected to a hand-tearing test (the force during the peeling of each embodiment and the comparative example was controlled to be the same). The material breaking effect was shown in FIG. Figure 1-16 , calculate the area ratio of white skin on the rock wool surface after stripping, and see Table 2 for the results.

[0074] 4. Horizontal tensile strength: According to the national standard GB / T1452 / 2018, the products provided in the examples and comparative examples were cured for 1 day to test the horizontal tensile strength of the three-layer structure (color steel plate-rock wool-color steel plate) (the amount of glue applied is 200g / m 2 ).

[0075] Table 2

[0076] It can be seen from the data in Table 2 that the polyol mixture of the polyurethane glue provided by Examples 1-3 has a suitable viscosity and density relative to Comparative Examples 1-13, and the polyurethane glue provided by Examples 1-3 has a higher flat tensile strength than Comparative Examples 1-13, and no white skin phenomenon occurs after the material is broken, which meets the actual application needs of the construction industry.

Claims

1. A high foaming polyurethane adhesive for metal sandwich panels, characterized in that: The invention comprises a polyol mixture and an isocyanate in a mass ratio of 5:(1.75-2.25); the raw materials for preparing the polyol mixture include, by weight, at least the following: 156-176 parts of castor oil, 260-280 parts of polyether polyol A having a hydroxyl value of 200-400 mgKOH / g, 85-95 parts of polyether polyol B having a hydroxyl value of 40-100 mgKOH / g, 0.8-1.2 parts of a wetting agent, 2.8-3.2 parts of dibutyltin dilaurate, 0.3-0.5 parts of triethylenediamine, 660-700 parts of a filler, 5-7 parts of fumed silica, 3.5-4.5 parts of glycerin, 7-9 parts of a foaming agent, 2.8-3.2 parts of a foam leveling agent, and 0.8-1.2 parts of a defoaming agent.

2. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The hydroxyl value of the polyether polyol A is 250-300 mgKOH / g, and the viscosity of the polyether polyol A at 25° C. is 50-120 mPa·s.

3. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The hydroxyl value of the polyether polyol B is 50-60 mgKOH / g, and the viscosity of the polyether polyol B at 25° C. is ≤700 mPa·s.

4. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The amount of the wetting agent added to the raw materials for preparing the polyol mixture is 0.8-1.2 parts by weight.

5. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The wetting agent is selected from at least one of BYK-W 966, BYK-9076, BYK-9077 and BYK-202.

6. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The foam leveling agent is selected from at least one of Maihao BL-3002, BL-8100, BL-8762 and Longsheng Sihai SH-493.

7. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The defoaming agent is selected from at least one of Sixin Technology SX-63, Hongtai X-2521, Ziyi Chemical ZY-1811 or BYK-A506.

8. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The viscosity of the isocyanate at 25° C. is 100-300 mPa·s.

9. The high foaming polyurethane adhesive for metal sandwich panels according to claim 1, characterized in that: The isocyanate has an isocyanate content of 20-40 wt %.

10. A method for preparing the high foaming polyurethane adhesive for metal sandwich panels according to any one of claims 1 to 9, characterized in that: The method comprises at least the following steps: adding castor oil, polyether polyol A, polyether polyol B, glycerin, fumed silica and a wetting agent into a container according to parts by weight, and stirring and mixing them at 1000-1500 r / min for 10-30 minutes; adding filler, and stirring and mixing them at 1000-1500 r / min for 60-90 minutes; adding dibutyltin dilaurate and triethylenediamine, and stirring and mixing them at 1000-1500 r / min for 10-30 minutes; adding a foaming agent, a defoaming agent and a foaming agent, and stirring and mixing them at 1000-1500 r / min for 10-30 minutes to obtain a polyol mixture; and when in use, blending the polyol mixture with isocyanate.

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