Environment-friendly polyurethane adhesive as well as preparation method and application thereof

Abstract

The invention discloses an environment-friendly polyurethane adhesive which comprises a component A and a component B. The component A is prepared from the following raw materials in parts by weight: 10-50 parts of vegetable oil, 5-30 parts of polyether polyol, 0.1-0.5 part of a chain extender, 40-70 parts of solid filler, 0.1-1 part of an auxiliary agent and 5-20 parts of an adsorbent. And the component B comprises a curing agent. According to the environment-friendly adhesive, the polyether polyol with the hydroxyl value of 270-290 mgKOH / g, the viscosity of 40-140 mPa.s at the temperature of 25 DEG C and the K < + > value content smaller than or equal to 3 ppm is adopted, and the environment-friendly adhesive can have long-term tensile shear strength and peel strength. The epoxy group-containing silane coupling agent 3-glycidyl ether oxypropyl trimethoxy silane is adopted, so that the service life of the polyurethane adhesive can be prolonged, the influence of external environment humidity on the adhesive is avoided, and the long-term peel strength and tensile shear strength of the adhesive are maintained.

Description

Technical Field

[0001] The invention relates to the field of C09J adhesives, and in particular to an environmentally friendly polyurethane adhesive and a preparation method and application thereof. Background Art

[0002] As people's environmental awareness increases, the excellent shock absorption, flame retardancy, sound insulation and thermal insulation properties of honeycomb panels are becoming more and more popular. Aluminum honeycomb panels are widely used in building decoration materials due to their light weight, high strength and high rigidity. Aluminum honeycomb cores are usually combined with aluminum plates to form a sandwich structure to further improve the strength of the material. The existing adhesives used to bond aluminum plates and aluminum honeycomb cores are mostly polyurethane adhesives, which have certain problems with durability. After long-term use, the peel strength of the polyurethane adhesive will decrease, causing cracking of the honeycomb core and the aluminum plate, affecting the service life. Therefore, it is very important to develop a polyurethane adhesive with a long service life and good bonding effect on the aluminum plate and the aluminum honeycomb core.

[0003] Chinese invention patent CN202311300563.8 discloses a honeycomb adhesive with good water resistance and a preparation method thereof. The honeycomb adhesive prepared by using a specific ratio of aromatic diisocyanate, polyester diol, polyether polyol, terminal hydroxyl polybutadiene, castor oil, chain extender and catalyst effectively improves the bonding performance of the honeycomb adhesive to the aluminum honeycomb panel, and also effectively improves the water resistance of the honeycomb adhesive. However, the service life of the adhesive has not been significantly improved. Chinese invention patent 202210917370.6 discloses an aldehyde-free plant adhesive and a preparation method thereof. The combination of polyadipate-1,4-butylene glycol ester diol, polyether polyol and castor oil modified polyol with a specific molecular weight can improve the glass transition temperature of the polyurethane adhesive, prolong the curing time of the polyurethane adhesive, and avoid the problem of high short-term hardness of the polyurethane adhesive caused by too fast curing rate and decreased hardness after long-term use. However, it is mainly used in the superimposed structure of honeycomb wood boards and solid wood boards, and is not suitable for the bonding of metal plates. Summary of the invention

[0004] In order to develop a polyurethane adhesive with a long service life and good bonding effect on aluminum plates and aluminum honeycomb cores, the first aspect of the present invention provides an environmentally friendly polyurethane adhesive, which includes component A and component B. The preparation raw materials of component A include, by weight: 10-50 parts of vegetable oil, 5-30 parts of polyether polyol, 0.1-0.5 parts of chain extender, 40-70 parts of solid filler, 0.1-1 parts of auxiliary agent, and 5-20 parts of adsorbent; the component B includes a curing agent.

[0005] As a preferred embodiment, the vegetable oil is selected from at least one of castor oil, soybean oil, linseed oil, sunflower oil and olive oil.

[0006] As a preferred embodiment, the castor oil is modified castor oil; preferably, the vegetable oil is a combination of modified castor oil and soybean oil, and the weight ratio of the modified castor oil to soybean oil is (10-30): (10-20).

[0007] As a preferred embodiment, the weight ratio of the modified castor oil to soybean oil is 20:10.

[0008] As a preferred embodiment, the polyether polyol has a hydroxyl value of 270-290 mgKOH / g, a viscosity of 40-140 mPa·s at 25° C., and a K+ value content of ≤3 ppm.

[0009] The inventors found in the experiment that the adhesive formed by using a polyether polyol with a hydroxyl value of 270-290 mgKOH / g and reacting with modified castor oil at a viscosity of 40-140 mPa·s has a higher viscosity and better tensile shear strength and peel strength. The possible reason is that the K+ content in the polyether polyol is ≤3ppm, which can avoid the decrease in the structural regularity of the polyurethane adhesive. A high content of K+ will catalyze the reaction of NCO with carbamate or urea groups to produce allophanate and biuret crosslinking bonds, resulting in a decrease in the regularity of the elastomer chemical structure and a decrease in mechanical properties.

[0010] As a preferred embodiment, the chain extender is propylene glycol.

[0011] As a preferred embodiment, the auxiliary agent includes at least one of a wetting agent, an adhesion promoter, a defoaming agent, a coupling agent, a leveling agent, and an antioxidant.

[0012] As a preferred embodiment, the auxiliary agent includes a wetting agent, an adhesion promoter, a defoaming agent, a coupling agent, and an antioxidant.

[0013] As a preferred embodiment, the auxiliary agent includes, by weight, 0.1-0.3 parts of a wetting agent, 0.1-0.3 parts of an adhesion promoter, 0.01-0.02 parts of a defoaming agent, 0.1-0.2 parts of a coupling agent, and 0.1-0.2 parts of an antioxidant.

[0014] As a preferred embodiment, the auxiliary agent includes, by weight, 0.2 parts of a wetting agent, 0.2 parts of an adhesion promoter, 0.01 parts of a defoaming agent, 0.1 parts of a coupling agent, and 0.1 parts of an antioxidant.

[0015] As a preferred embodiment, the adhesion promoter has a viscosity of 350-650 mPa·s at 23° C. and an acid value of 20-30 mgKOH / g.

[0016] During the experiment, the inventors found that the use of a specific adhesion promoter can optimize the adhesion of the polyurethane adhesive to the metal plate and the honeycomb core substrate, and extend the use time of the adhesive. The possible reason is speculated to be: the use of a silicone-free non-ionic compound adhesion promoter, the hydroxyl and carboxyl groups contained in it can participate in the reaction to increase the softness of the adhesive, so that the adhesive and the substrate have better adhesion. In particular, the gaps in the honeycomb core are large, and the contact area between the honeycomb core and the adhesive is small. After long-term use, there is a problem of decreased peel strength. By introducing an adhesion promoter with an acid value of 20-30 mgKOH / g, the edge adhesion of the adhesive to the substrate can be increased, and the peel strength after long-term use can be improved.

[0017] As a preferred embodiment, the coupling agent is a silane coupling agent, and the silane coupling agent is selected from at least one of β-(3,4-epoxycyclohexane)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, and 3-glycidyloxypropylmethyldiethoxysilane.

[0018] As a preferred embodiment, the coupling agent is 3-glycidyloxypropyltrimethoxysilane.

[0019] The inventors found during the experiment that the use of epoxy-containing silane coupling agents can extend the service life of polyurethane adhesives, avoid the influence of external environmental humidity on the adhesive, and maintain the long-term peel strength and tensile shear strength of the adhesive. The possible reasons are speculated to be: the epoxy-containing silane coupling agent can react with isocyanate to form a urea bond, thereby avoiding the reaction of isocyanate with the hydroxyl group of the external environment, reducing the influence of external environmental humidity on the adhesive, and at the same time, the formation of urea bonds increases the spatial resistance of water entering the adhesive, thereby maintaining the long-term peel strength and tensile shear strength of the adhesive and extending the service life.

[0020] As a preferred embodiment, the solid filler is selected from at least one of silicon dioxide, calcium carbonate, activated calcium, calcium chloride, silicon micropowder and talc.

[0021] As a preferred embodiment, the solid filler comprises a combination of silicon dioxide, calcium carbonate and active calcium, and the weight ratio of silicon dioxide, calcium carbonate and active calcium is (1-5): (40-60): (3-8).

[0022] As a preferred embodiment, the weight ratio of silicon dioxide, calcium carbonate and active calcium is 1:50:5.

[0023] As a preferred embodiment, the silicon dioxide is hydrophilic nano-fumed silicon dioxide. Preferably, the particle size of the nano-fumed silicon dioxide is 200 meshes.

[0024] As a preferred embodiment, the adsorbent is a molecular sieve, and preferably, the molecular sieve is a 4A grade molecular sieve.

[0025] As a preferred embodiment, the B component is diphenylmethane diisocyanate.

[0026] As a preferred embodiment, the weight ratio of component A to component B is (1-5):1.

[0027] As a preferred embodiment, the weight ratio of component A to component B is 4:1.

[0028] A second aspect of the present invention provides a method for preparing an environmentally friendly polyurethane adhesive, comprising the following steps:

[0029] S1: Mix polyether polyol, vegetable oil and chain extender evenly and then add silicon dioxide;

[0030] After S2 is evenly dispersed, calcium carbonate, active calcium and adsorbent are added and dispersed at high speed;

[0031] Add additives to S3 and disperse evenly, cool to 50°C and discharge to obtain component A;

[0032] S4: Mix component A and component B to obtain an adhesive.

[0033] As a preferred embodiment, the high-speed dispersion speed in step S2 is 1000-2000 r / min, and the reaction temperature is 70-80°C.

[0034] As a preferred embodiment, the high-speed dispersion speed in step S2 is 1500 r / min and the reaction temperature is 75°C.

[0035] The third aspect of the present invention provides an application of an environmentally friendly polyurethane adhesive, which is applied to the bonding structure of color steel plates, aluminum plates, and honeycomb panels. The bonded aluminum honeycomb panels are applied to home ceilings, interior wall decorations, and home cabinets.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The environmentally friendly polyurethane adhesive of the present invention uses a polyether polyol with a hydroxyl value of 270-290 mgKOH / g, a viscosity of 40-140 mPa·s at 25° C., and a K+ value content of ≤3 ppm, so that the environmentally friendly adhesive has long-term tensile shear strength and peel strength.

[0038] (2) The environmentally friendly polyurethane adhesive of the present invention uses an adhesion promoter with a viscosity of 350-650 mPa·s at 23°C and an acid value of 20-30 mgKOH / g, which can increase the bonding performance of the polyurethane adhesive with color-coated steel plates, aluminum plates and aluminum honeycomb cores, and avoid a decrease in adhesion to the substrate during long-term use.

[0039] (3) The environmentally friendly polyurethane adhesive of the present invention uses 3-glycidyloxypropyltrimethoxysilane, a silane coupling agent containing an epoxy group, which can extend the service life of the polyurethane adhesive, avoid the influence of external environmental humidity on the adhesive, and maintain the long-term peel strength and tensile shear strength of the adhesive.

[0040] (4) The environmentally friendly polyurethane adhesive of the present invention adopts a solid filler combination of silicon dioxide, calcium carbonate, and active calcium, which can optimize the wetting and leveling properties of the polyurethane adhesive and achieve smooth construction on the surfaces of color-coated steel plates, aluminum plates, and aluminum honeycomb cores.

[0041] (5) The environmentally friendly polyurethane adhesive of the present invention can maintain long-term stable and good tensile shear strength and peel strength, and has stable performance and long service life. DETAILED DESCRIPTION

[0042] Example

[0043] An environmentally friendly polyurethane adhesive comprises a component A and a component B, wherein the weight ratio of the component A to the component B is 4: 1. The component B is diphenylmethane diisocyanate purchased from Wanhua, and the model is PM200.

[0044] The raw materials for preparing the A component are shown in the following Table 1 in parts by weight:

[0045] Table 1

[0046]

[0047] The polyether polyol has a hydroxyl value of 270-290 mgKOH / g, a viscosity of 40-140 mPa·s at 25° C., and a K + Value content ≤3ppm.

[0048] The adhesion promoter has a viscosity of 350-650 mPa·s at 23° C. and an acid value of 20-30 mgKOH / g.

[0049] The coupling agent is 3-glycidyloxypropyltrimethoxysilane.

[0050] A method for preparing an environmentally friendly polyurethane adhesive comprises the following steps:

[0051] S1: Mix polyether polyol, vegetable oil and chain extender evenly and then add silicon dioxide;

[0052] After S2 is evenly dispersed, calcium carbonate, active calcium and adsorbent are added and dispersed at high speed;

[0053] Add additives to S3 and disperse evenly, cool to 50°C and discharge to obtain component A;

[0054] S4: Mix component A and component B to obtain an adhesive.

[0055] The high-speed dispersion speed in step S2 is 1500 r / min and the reaction temperature is 75°C.

[0056] Comparative Example 1

[0057] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the adhesion promoter is purchased from Rieter Resin, model number LD-3127.

[0058] Comparative Example 2

[0059] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the adhesion promoter is purchased from AFCONA, and the model number is AFCONA K197-1-2.

[0060] Comparative Example 3

[0061] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the adhesion promoter is purchased from AFCONA, model number AFCONA S776-2.

[0062] Comparative Example 4

[0063] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the adhesion promoter is a phosphate adhesion promoter purchased from BYK, model BYK-4511.

[0064] Comparative Example 5

[0065] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the polyether polyol is purchased from Longhua New Materials, model LE-204.

[0066] Comparative Example 6

[0067] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the polyether polyol is purchased from INOV, model number C204.

[0068] Comparative Example 7

[0069] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the polyether polyol is purchased from INOV, model C210 (bifunctional, average molecular weight 1000Da).

[0070] Comparative Example 8

[0071] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the modified castor oil is purchased from Shanghai Jingri Chemical Industry, model number AF4320.

[0072] Comparative Example 9

[0073] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the modified castor oil is purchased from Shanghai Jingri Chemical Industry, model A21.

[0074] Comparative Example 10

[0075] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the modified castor oil is purchased from Shanghai Jingri Chemical Industry, model number AF4330.

[0076] Comparative Example 11

[0077] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the soybean oil is replaced by Feihang Technology soybean oil polyol FH-27150.

[0078] Comparative Example 12

[0079] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the polyether polyol is purchased from Dongda, and the model number is 204.

[0080] Comparative Example 13

[0081] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the silicon dioxide is purchased from Wacker, and the model number is N20.

[0082] Comparative Example 14

[0083] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the silicon dioxide is purchased from Cabot Gas Silica, model number CAB-O-SIL MS60.

[0084] Comparative Example 15

[0085] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the coupling agent is purchased from Hubei Xinlantian, and the model is silane coupling agent LT-560.

[0086] Comparative Example 16

[0087] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the coupling agent is purchased from Hubei Xinlantian, and the model is silane coupling agent LT-171.

[0088] Comparative Example 17

[0089] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the coupling agent is purchased from Nanjing Xuanhao, model KH-540.

[0090] Comparative Example 18

[0091] An environmentally friendly polyurethane adhesive and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the amount of the wetting agent, adhesion promoter, and coupling agent added is 0 parts.

[0092] Performance Testing

[0093] The bonding substrate is an aluminum plate, an aluminum honeycomb core, and an aluminum plate sandwich structure. The polyurethane adhesive prepared in the embodiment and the comparative example is coated between the aluminum plate and the aluminum honeycomb core. The thickness of the aluminum plate is 2.5 mm, the thickness of the aluminum honeycomb core is 8 mm, the thickness of the adhesive layer is 1 mm, and the test is performed after curing at 25°C for 7-8 hours.

[0094] 1. Tensile shear strength: The tensile shear strength of the polyurethane adhesive prepared according to GB / T 7124-2008 standard was tested at 1 day, 3 days, 7 days and 1 month.

[0095] 2. Peel strength: The peel strength of the polyurethane adhesive prepared according to GB / T 1457-2005 standard was tested at 1 day, 3 days, 7 days and 1 month.

[0096] Six samples were tested each time and the average value was taken. The test results are shown in Table 2.

[0097] Table 2

[0098]

Claims

1. An environmentally friendly polyurethane adhesive, characterized in that: The environmentally friendly polyurethane adhesive comprises component A and component B. The raw materials for preparing component A include, by weight, 10-50 parts of vegetable oil, 5-30 parts of polyether polyol, 0.1-0.5 parts of chain extender, 40-70 parts of solid filler, 0.1-1 parts of auxiliary agent, and 5-20 parts of adsorbent; and component B comprises a curing agent.

2. The environmentally friendly polyurethane adhesive according to claim 1, characterized in that: The vegetable oil is selected from at least one of castor oil, soybean oil, linseed oil, sunflower oil and olive oil.

3. The environmentally friendly polyurethane adhesive according to claim 1, characterized in that: The polyether polyol has a hydroxyl value of 270-290 mgKOH / g, a viscosity of 40-140 mPa·s at 25° C., and a K + Value content ≤3ppm.

4. The environmentally friendly polyurethane adhesive according to claim 1, characterized in that: The auxiliary agent includes at least one of a wetting agent, an adhesion promoter, a defoaming agent, a coupling agent, a leveling agent, and an antioxidant.

5. The environmentally friendly polyurethane adhesive according to claim 4, characterized in that: The adhesion promoter has a viscosity of 350-650 mPa·s at 23° C. and an acid value of 20-30 mgKOH / g.

6. The environmentally friendly polyurethane adhesive according to claim 4, characterized in that: The coupling agent is a silane coupling agent, and the silane coupling agent is selected from at least one of β-(3,4-epoxycyclohexane)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, and 3-glycidyloxypropylmethyldiethoxysilane.

7. The environmentally friendly polyurethane adhesive according to claim 1, characterized in that: The solid filler is selected from at least one of silicon dioxide, calcium carbonate, active calcium, calcium chloride, silicon micropowder and talc.

8. The environmentally friendly polyurethane adhesive according to claim 7, characterized in that: The solid filler comprises a combination of silicon dioxide, calcium carbonate and active calcium, and the weight ratio of silicon dioxide, calcium carbonate and active calcium is (1-5): (40-60): (3-8).

9. A method for preparing the environmentally friendly polyurethane adhesive according to any one of claims 7-8, characterized in that: The following steps are involved: S1: Mix polyether polyol, vegetable oil and chain extender evenly and then add silicon dioxide; After S2 is evenly dispersed, calcium carbonate, active calcium and adsorbent are added and dispersed at high speed; Add additives to S3 and disperse evenly, cool to 50°C and discharge to obtain component A; S4: Mix component A and component B to obtain an adhesive.

10. An application of the environmentally friendly polyurethane adhesive according to any one of claims 7-8, characterized in that: Used in the bonding structure of color steel plates, aluminum plates and honeycomb plates.

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