Cold-pressing adhesive for air pipe as well as preparation method and application of cold-pressing adhesive

Abstract

The cold-pressing adhesive for the air duct comprises a component A and a component B. The component A comprises the following components in parts by weight: 265-285 parts of castor oil, 90-120 parts of polyether polyol, 1-4 parts of propylene glycol, 800-1000 parts of a filler, 2-8 parts of an ester solvent, 0.5-3 parts of a silane coupling agent, 0.1-1 part of a catalyst and 0.2-2.5 parts of a foaming agent. The component B comprises isocyanate; the catalyst is a combination of bis (dimethylamino) ethyl ether and diethyl diamine. The opening time of the prepared cold-pressing adhesive is about 40 min, the foaming rate reaches 130%, the shore hardness of an adhesive film is larger than 95, and the good material breaking effect can be achieved when the cold-pressing adhesive is applied to preparation of a glass magnesium composite board.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a cold-pressed adhesive for air ducts and a preparation method thereof. Background Art

[0002] In the field of air duct manufacturing, two-component polyurethane adhesives are widely used due to their excellent mechanical properties, but there are still significant defects. First, the traditional catalyst system (such as stannous octoate, diamine butyl, etc.) has insufficient catalytic activity for the foaming reaction, which leads to prolonged glue rise time and poor thixotropy. It is easy to produce sagging on the surface of the substrate during construction, which seriously affects the process efficiency and product quality. Secondly, physical or chemical foaming agents (such as azodicarbonamide, isopentane, etc.) have environmental pollution or process compatibility issues. Azo foaming agents release harmful gases when decomposed, and sodium bicarbonate easily forms insoluble particles due to poor solubility. Low-boiling point substances such as isopentane cause production safety hazards due to volatilization. These problems not only limit the scope of application of adhesives, but also increase environmental pollution.

[0003] Chinese invention patent application CN107384258A discloses a cold-pressed adhesive and its preparation method. The adhesive comprises the following components by weight: 90% VAE emulsion, 9% water-based polyurethane emulsion, 0.5% defoamer, and 0.5% preservative. The adhesive is capable of ultra-fast curing and possesses higher bond strength than conventional cold-pressed adhesives. However, the adhesive is only suitable for bonding wood together and is not suitable for bonding glass-magnesium composite panels, the material used for air ducts. Summary of the Invention

[0004] A first aspect of the present invention provides a cold-pressed adhesive for air ducts, comprising component A and component B. Component A comprises, by weight, 265-285 parts of castor oil, 90-120 parts of polyether polyol, 1-4 parts of propylene glycol, 800-1000 parts of filler, 2-8 parts of ester solvent, 0.5-3 parts of silane coupling agent, 0.1-1 parts of catalyst, and 0.2-2.5 parts of foaming agent; component B comprises isocyanate; and the catalyst is a combination of bisdimethylaminoethyl ether and diethylenediamine.

[0005] The catalyst, a combination of bis(dimethylaminoethyl)ether and diethylenediamine, maintains the foaming rate while extending the open time to 40 minutes. The dimethylamino groups and ether bonds in the bis(dimethylaminoethyl)ether molecule rapidly catalyze the reaction between isocyanate and water, promoting the release of carbon dioxide and thus forming a foam structure. The addition of diethylenediamine catalyzes the gelation of the polyurethane, preventing excessive foaming that can lead to numerous defects in the adhesive layer. Further research has found that by limiting the weight ratio of bis(dimethylaminoethyl)ether to diethylenediamine to 1:1.5-4, the foaming rate can be further increased to over 100%, while also improving bond strength. This specific ratio of the two catalysts achieves a dynamic balance between the foaming and gelation reactions. After bis(dimethylaminoethyl)ether initiates the foaming reaction, the system rapidly expands, while diethylenediamine subsequently dominates the gelation reaction, shortening the crosslinking time and preventing foam collapse or cracking caused by excessive foaming.

[0006] The weight ratio of the bisdimethylaminoethyl ether to diethylenediamine is 1:(1.5-4).

[0007] Optionally, the weight ratio of the bisdimethylaminoethyl ether to diethylenediamine is 1:(2-4).

[0008] The polyether polyol comprises polyether polyol A and polyether polyol B. The polyether polyol A has a number average molecular weight of 800-1500 and a hydroxyl value of 90-150 mg KOH / g; the polyether polyol B has a number average molecular weight of 2500-4000 and a hydroxyl value of 40-80 mg KOH / g.

[0009] Optionally, the number average molecular weight of the polyether polyol A is 800-1200, and the hydroxyl value is 90-130 mg KOH / g; the number average molecular weight of the polyether polyol B is 2500-3500, and the hydroxyl value is 40-70 mg KOH / g.

[0010] Optionally, the polyether polyol A has a number average molecular weight of 900-1100 and a hydroxyl value of 102-125 mg KOH / g, and is provided by Dow Chemical with the designation 1000LM; the polyether polyol B has a number average molecular weight of 3000 and a hydroxyl value of 56 mg KOH / g, and is provided by Dow Chemical with the designation 3003LM.

[0011] The weight ratio of the polyether polyol A to the polyether polyol B is 1:(6-12).

[0012] Optionally, the weight ratio of the polyether polyol A to the polyether polyol B is 1:(8-12).

[0013] The polyether polyol includes polyether polyol A and polyether polyol B. The number average molecular weight of polyether polyol A is 800-1500 and the hydroxyl value is 90-150 mg KOH / g. The number average molecular weight of polyether polyol B is 2500-4000 and the hydroxyl value is 40-80 mg KOH / g, which can improve the bonding strength of the cold-pressed adhesive. The high hydroxyl value of polyether polyol A can enable more hydroxyl groups to participate in cross-linking when reacting with isocyanate, forming a dense chemical bond network, thereby improving the cohesive strength and interfacial bonding strength of the adhesive. Polyether polyol B has a lower hydroxyl value but a higher molecular weight, and its long chain structure can provide flexibility and segment fluidity. The high molecular weight polyether forms a longer soft segment during curing, which enhances the toughness of the material through physical entanglement and hydrogen bonding, avoiding brittle fracture caused by excessive cross-linking. The two are compounded to form a composite structure of rigid skeleton + flexible filling.

[0014] Further research revealed that by limiting the weight ratio of polyether polyol A to polyether polyol B to 1:(6-12), the resulting cold-pressed adhesive can meet the requirements for the preparation of glass-magnesium composite panels, particularly for achieving a material-breaking effect between the glass-magnesium board and the iron sheet. Polyether polyol B forms a continuous phase, providing primary mechanical support and deformation resistance. Its low hydroxyl value slows crosslinking, prolongs the operating time, and ensures sufficient wetting of the adhesive at the interface between the glass-magnesium board and the iron sheet. Polyether polyol A, dispersed as a reinforcing phase within the polyether polyol B matrix, preferentially reacts with isocyanate to form high-crosslink density microdomains, strengthening interfacial bonding. This dual-phase structure sacrifices some flexibility in exchange for higher interfacial strength.

[0015] The ester solvent includes a dibasic acid ester.

[0016] Optionally, the dibasic acid ester includes at least one of dimethyl succinate, dimethyl glutarate, and dimethyl adipate.

[0017] Optionally, the silane coupling agent includes an isocyanate silane derivative.

[0018] Optionally, the isocyanate silane derivative includes at least one of 3-isocyanatepropyltriisopropoxysilane, 3-isocyanateethyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, isocyanatepropyltriethoxysilane, and γ-isocyanatepropyltriethoxysilane-acrylate copolymer.

[0019] The foaming agent is water.

[0020] The weight ratio of the dibasic acid ester, water and silane coupling agent is 1:(0.2-0.4):(0.2-0.4).

[0021] Optionally, the weight ratio of the dibasic acid ester, water and silane coupling agent is 1:(0.25-0.35):(0.25-0.35).

[0022] The filler includes ground calcium carbonate and fumed silica.

[0023] The weight ratio of the heavy calcium carbonate to the filler is greater than 95%.

[0024] Optionally, the weight ratio of the heavy calcium carbonate to the filler is greater than 99%.

[0025] The second aspect of the present invention provides a method for preparing cold-pressed adhesive for air ducts, comprising the following steps: mixing castor oil, polyether polyol, propylene glycol, and fumed silica in sequence, adding heavy calcium carbonate and stirring evenly, then adding an ester solvent and a silane coupling agent and stirring evenly, then adding a catalyst and a foaming agent and stirring evenly, and filtering to obtain component A; preparing isocyanate to obtain component B.

[0026] A third aspect of the present invention provides an application of a cold-pressed adhesive for air ducts, which is applied to the preparation of glass-magnesium composite panels.

[0027] The glass-magnesium composite board comprises a glass-magnesium board and iron sheet.

[0028] Beneficial effects:

[0029] 1. The catalyst is a combination of bis(dimethylaminoethyl)ether and diethylenediamine, which can increase the foaming time to 40 minutes while maintaining the foaming rate.

[0030] 2. By limiting the weight ratio of bis(dimethylaminoethyl)ether to diethylenediamine to 1:(1.5-4), the foaming rate can be further increased to more than 100%, and the bonding strength can be improved at the same time.

[0031] 3. The bonding strength can be further improved by using two polyether polyols with different viscosities and hydroxyl values.

[0032] 4. By limiting the weight ratio of polyether polyol A and polyether polyol B to 1:(6-12), the prepared cold-pressed adhesive can meet the preparation of glass-magnesium composite boards, especially can improve the material breaking effect between glass-magnesium boards and iron sheets.

[0033] 5. The cold-pressed adhesive prepared by the present invention has a Shore hardness greater than 95. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the material breaking effect of the cold pressed adhesive in Example 1.

[0035] Figure 2 This is the material breaking effect of the cold pressed adhesive in Example 2.

[0036] Figure 3 This is the material breaking effect of the cold pressed adhesive in Example 3.

[0037] Figure 4 This is the material breaking effect of the cold pressed adhesive in Example 4.

[0038] Figure 5 This is the material breaking effect of the cold pressed adhesive in Comparative Example 1.

[0039] Figure 6 This is the material breaking effect of the cold pressed adhesive in Comparative Example 2.

[0040] Figure 7 This is the material breaking effect of the cold pressed adhesive in comparative example 3.

[0041] Figure 8 This is the material breaking effect of the cold pressed adhesive in comparative example 4.

[0042] Figure 9 This is the material breaking effect of the cold pressed adhesive in comparative example 5.

[0043] Figure 10 This is the material breaking effect of the cold pressed adhesive in Comparative Example 6.

[0044] Figure 11 This is the material breaking effect of the cold pressed adhesive in comparative example 7.

[0045] Figure 12 This is the material breaking effect of the cold pressed adhesive in Comparative Example 8.

[0046] Figure 13 This is the material breaking effect of the cold pressed adhesive in Comparative Example 9.

[0047] Figure 14 This is the material breaking effect of the cold pressed adhesive in Comparative Example 10.

[0048] Figure 15 This is the material breaking effect of the cold pressed adhesive in comparative example 11.

[0049] Figure 16 This is the material breaking effect of the cold pressed adhesive in Comparative Example 12.

[0050] Figure 17 This is the material breaking effect of the cold pressed adhesive in comparative example 13.

[0051] Figure 18 This is the material breaking effect of the cold pressed adhesive in Comparative Example 14.

[0052] Figure 19 This is the material breaking effect of the cold pressed adhesive in Comparative Example 15.

[0053] Figure 20 This is the material breaking effect of the cold pressed adhesive in Comparative Example 16.

[0054] Figure 21 This is the material breaking effect of the cold pressed adhesive in Comparative Example 17. DETAILED DESCRIPTION

[0055] Example 1

[0056] A cold-pressed adhesive for air ducts, consisting of component A and component B, wherein component A comprises, by weight, 270 parts of castor oil (Tongliao Rihao Castor Technology, PP grade castor oil), 110 parts of polyether polyol, 2 parts of propylene glycol, 901 parts of filler, 5 parts of ester solvent (dibasic acid ester, DBE), 1.5 parts of silane coupling agent (isocyanate propyl triethoxysilane), 0.4 parts of catalyst, and 1.5 parts of foaming agent (water); component B is isocyanate (MDI, purchased from Wanhua Chemical PM-400).

[0057] The catalyst is a combination of bisdimethylaminoethyl ether and diethylenediamine, and the weight ratio of the bisdimethylaminoethyl ether to diethylenediamine is 1:3.

[0058] The polyether polyol A has a number average molecular weight of 900-1100 and a hydroxyl value of 102-125 mg KOH / g, and is provided by Dow Chemical under the designation 1000LM. The polyether polyol B has a number average molecular weight of 3000 and a hydroxyl value of 56 mg KOH / g, and is provided by Dow Chemical under the designation 3003LM.

[0059] The weight ratio of the polyether polyol A to the polyether polyol B is 1:10.

[0060] The filler is heavy calcium carbonate (Lingshou County Shanchuan Mineral Products Processing Plant, 1250 mesh) and fumed silica (Shandong Wanhua Tianhe New Materials, A200 fumed silica), and the weight ratio of the heavy calcium carbonate to the fumed silica is 900:1.

[0061] A preparation method of a cold-pressed adhesive for air ducts comprises the following steps: sequentially adding castor oil, polyether polyol, propylene glycol, and fumed silica into a dispersion kettle, adjusting the speed to 800 r / min and stirring for 5 minutes; adjusting the speed to 1300 r / min, adding heavy calcium carbonate, and vacuum stirring for 65 minutes; adding a divalent acid ester and a silane coupling agent, and vacuum stirring for 10 minutes; adding bisdimethylaminoethyl ether, diethylenediamine, and water, and vacuum stirring for 25 minutes; filtering through a 100-mesh nylon filter bag to obtain component A; and preparing isocyanate to obtain component B.

[0062] Example 2

[0063] The specific implementation is the same as that of Example 1; the difference is that the weight portion of castor oil is 280 parts.

[0064] Example 3

[0065] The specific implementation is the same as that of Example 1; the difference is that the weight portion of the polyether polyol is 90 parts.

[0066] Example 4

[0067] The specific implementation is the same as that of Example 1; the difference is that the weight portion of the polyether polyol is 120 parts.

[0068] Comparative Example 1

[0069] The specific implementation is the same as that of Example 1; the difference is that the weight portion of castor oil is 260 parts.

[0070] Comparative Example 2

[0071] The specific implementation is the same as that of Example 1; the difference is that the weight ratio of the polyether polyol A to the polyether polyol B is 2:9.

[0072] Comparative Example 3

[0073] The specific implementation is the same as that of Example 1; the difference is that the polyether polyol is polyether polyol B.

[0074] Comparative Example 4

[0075] The specific implementation is the same as in Example 1; the difference is that propylene glycol is not added.

[0076] Comparative Example 5

[0077] The specific implementation is the same as that of Example 1; the difference is that the weight portion of propylene glycol is 5 parts.

[0078] Comparative Example 6

[0079] The specific implementation is the same as that of Example 1; the difference is that no ester solvent is added.

[0080] Comparative Example 7

[0081] The specific implementation is the same as that of Example 1; the difference is that the weight portion of the ester solvent is 10 parts.

[0082] Comparative Example 8

[0083] The specific implementation is the same as that of Example 1; the difference is that no silane coupling agent is added.

[0084] Comparative Example 9

[0085] The specific implementation is the same as that of Example 1; the difference is that the weight portion of the silane coupling agent is 3 parts.

[0086] Comparative Example 10

[0087] The specific implementation is the same as that of Example 1; the difference is that the catalyst is 0.1 parts by weight of stannous octoate.

[0088] Comparative Example 11

[0089] The specific implementation is the same as that of Example 1; the difference is that the catalyst is 0.4 parts of 1,3-butanediamine.

[0090] Comparative Example 12

[0091] The specific implementation is the same as that of Example 1; the difference is that the weight portion of the catalyst is 0.4 parts of triethylamine.

[0092] Comparative Example 13

[0093] The specific implementation is the same as that of Example 1, except that the weight portion of the catalyst is 0.1 parts of DBDTL.

[0094] Comparative Example 14

[0095] The specific implementation is the same as that of Example 1; the difference is that the weight ratio of bisdimethylaminoethyl ether to diethylenediamine is 3:1.

[0096] Comparative Example 15

[0097] The specific implementation is the same as that of Example 1; the difference is that the weight ratio of bisdimethylaminoethyl ether to diethylenediamine is 1:1.

[0098] Comparative Example 16

[0099] The specific implementation is the same as that of Example 1; the difference is that the weight portion of the catalyst is 0.4 parts of diethylenediamine.

[0100] Comparative Example 17

[0101] The specific implementation is the same as that of Example 1; the difference is that the weight portion of the foaming agent is 3 parts.

[0102] Comparative Example 18

[0103] The specific implementation is the same as that of Example 1; the difference is that the foaming agent is sodium bicarbonate, and the weight portion of the foaming agent is 10 parts.

[0104] Performance testing methods

[0105] The following performance tests were carried out in the embodiments and comparative examples, and the test data are listed in Table 1.

[0106] 1. Open time: After the glue components A and B are evenly mixed at a ratio of 100:20 (weight ratio), apply (250g / square meter) on the surface of the substrate (aluminum sheet). The open time is determined when the state of the film changes from wet to no stringiness or no stickiness when touched (any of the conditions is met).

[0107] 2. Foaming Rate: At 25°C, 40% humidity, and 760 mmHg, blend components A and B at a 100:20 weight ratio. Pour 40 mL of the mixed glue into a 200 mL graduated cylinder. When the liquid level stops rising, record the volume of the glue. Calculate the foaming rate using the formula (Foaming Rate = (Final Foam Volume - 40 mL) / 40 mL × 100%). After blending components A and B at a 100:20 weight ratio, measure the volume of the foam before and after foaming and calculate the foaming rate using the formula (Foaming Rate = (Final Foam Volume - Volume Before Foaming) / Volume Before Foaming × 100%).

[0108] 3. Initiation time: In an environment of 25°C, humidity 40% RH, and air pressure 760 mmHg, mix components A and B in a ratio of 100:20 (weight ratio). Start timing after mixing evenly. Pour 40 mL of the mixed glue into a 200 mL measuring cylinder. When the liquid level rises from 40 mL to 41 mL, the timing ends and the recorded time is recorded as the initiation time of the glue.

[0109] 4. Foaming time: In an environment of 25°C, humidity 40% RH, and air pressure 760 mmHg, mix components A and B at a ratio of 100:20 (weight ratio). Pour 40 mL of the mixed glue into a 200 mL graduated cylinder. Start timing when the liquid level rises from 40 mL to 41 mL. Stop timing when the glue volume no longer increases. The recorded time is recorded as the foaming time of the glue.

[0110] 5. Film hardness: Shore A hardness tester is used for testing.

[0111] 6. Material breaking effect: After the A and B components are blended at a ratio of 100:20 (weight ratio), they are coated (320g / square meter) on the glass magnesium board, compounded with the iron sheet, and pressed to the limit (3 tons) using a press. After pressing at 25°C for 8 hours, the pressure is released. After curing for 24 hours, the glass magnesium board is laid flat, the iron sheet is clamped with pliers, and the iron sheet is completely peeled off at an angle of about 45° to observe the material breaking effect. All test samples were tested using the same method. The sizes of the glass magnesium and iron sheet were unified to 150mm×200mm. The hand-tearing direction was consistent in each experiment, with a force of 500N to ensure that the material was completely peeled off. The material breaking effect of the cold-pressed adhesive in Example 1 is as follows: Figure 1 As shown, the material breaking effect of the cold pressed adhesive of Example 2 is as follows Figure 2 As shown, the material breaking effects of the cold pressed adhesives of Comparative Examples 1-17 correspond to Figure 5-21 Calculation of material breakage rate: Residual area of ​​the core material on the contact surface = (residual area / theoretical maximum area) × 100%. If the calculated result is less than 5%, it is recorded as 0%. If it is greater than 5%, it is rounded up according to the calculated result.

[0112] The " / " is not tested.

[0113] In Comparative Example 18, the glue could not pass through the filter bag during filtration during the preparation process, and no testing was performed.

[0114] Performance test data

[0115] Table 1

[0116]

[0117] Combined with Table 1 and Figure 1-21 The present invention can only achieve the following simultaneous results: an open time of about 40 minutes, a foaming rate of 130%, and a film Shore hardness greater than 95 under specific components and addition amounts, especially a specific catalyst combination and its compounding ratio. When applied to the preparation of glass-magnesium composite panels, it can achieve good material breaking effect.

Claims

1. A cold-pressed adhesive for air ducts, characterized in that: The invention comprises component A and component B, wherein component A comprises, by weight, 265-285 parts of castor oil, 90-120 parts of polyether polyol, 1-4 parts of propylene glycol, 800-1000 parts of filler, 2-8 parts of ester solvent, 0.5-3 parts of silane coupling agent, 0.1-1 parts of catalyst, and 0.2-2.5 parts of foaming agent; component B comprises isocyanate; and the catalyst is a combination of bisdimethylaminoethyl ether and diethylenediamine; The weight ratio of the bisdimethylaminoethyl ether to diethylenediamine is 1:(1.5-4); The polyether polyol comprises polyether polyol A and polyether polyol B, wherein the number average molecular weight of the polyether polyol A is 800-1500 and the hydroxyl value is 90-150 mg KOH / g; the number average molecular weight of the polyether polyol B is 2500-4000 and the hydroxyl value is 40-80 mg KOH / g; and the weight ratio of the polyether polyol A to the polyether polyol B is 1:(6-12); The ester solvent includes a dibasic acid ester, and the weight ratio of the dibasic acid ester, water and silane coupling agent is 1:(0.2-0.4):(0.2-0.4).

2. The cold-pressed adhesive for air ducts according to claim 1, characterized in that: The foaming agent is water. The weight ratio of the dibasic acid ester, water and silane coupling agent is 1:(0.2-0.4):(0.2-0.4).

3. The cold-pressed adhesive for air ducts according to claim 1, characterized in that: The filler includes ground calcium carbonate and fumed silica.

4. The cold-pressed adhesive for air ducts according to claim 3, characterized in that: The weight ratio of the heavy calcium carbonate to the filler is greater than 95%.

5. A method for preparing the cold-pressed adhesive for air ducts according to claim 4, characterized in that: The following steps are involved: Castor oil, polyether polyol, propylene glycol, and fumed silica are mixed in sequence, heavy calcium carbonate is added and stirred evenly, an ester solvent and a silane coupling agent are added and stirred evenly, a catalyst and a foaming agent are added and stirred evenly, and component A is obtained after filtering; isocyanate is prepared to obtain component B.

6. An application of the cold-pressed adhesive for air ducts according to any one of claims 1 to 5, characterized in that: Used in the preparation of glass magnesium composite panels.

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