Delay thermosensitive two-component polyurethane adhesive and preparation method thereof

Abstract

The invention discloses a delayed thermosensitive two-component polyurethane adhesive and a preparation method thereof, the adhesive is formed by mixing a component A and a component B according to the mass ratio of (1-5): 1, the component A is polyhydric alcohol prepared from the following raw materials in percentage by mass: 1-5% of a solvent, 1-5% of a catalyst, 1-5% of a catalyst, 1-5% of a catalyst and 1-5% of a solvent. Comprising 20-48% of a hydroxyl-terminated polyurethane prepolymer, 30-58% of a modified filler, 5-15% of a molecular sieve, 0.5-1.5% of a coupling agent, 1-5% of a cross-linking agent and 0.1-1% of a delayed thermosensitive catalyst, and the component B adopts polyisocyanate. The adhesive is wide in bonding base materials, the bonding base materials comprise wood, SMC, metal, PVC and the like, the bonding performance is excellent, the aluminum sheet / aluminum sheet bonding strength reaches 10 MPa or above, the operation time at the normal temperature is long, rapid curing can be achieved after temperature rise, the reaction speed at the high temperature is 2-3 times higher than that of a conventional catalyst, rapid sizing is achieved, and the adhesive is suitable for large-scale production. And the method can be widely applied to industries with fast production rhythm.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane adhesives, and particularly to a delayed thermosensitive two-component polyurethane adhesive and a preparation method thereof. Background Art

[0002] Polyurethane adhesives refer to adhesives containing urethane groups (-NHCOO-) and / or isocyanate groups (-NCO) in the molecular chain. Polyurethane adhesives are divided into two categories: polyurethanes and polyisocyanates, and are an important component of rapidly developing polyurethane resins. They have excellent performance and are widely used in various industries. They are an important synthetic adhesive. In polyurethane adhesives, due to the presence of -NCO groups and -NH groups, they have high reactivity, good adhesion to various materials, can be cured at room temperature, are impact-resistant, have tough adhesive films, high peel strength, good flexibility, and excellent oil resistance, wear resistance, and ultra-low temperature resistance. Therefore, they are widely used in industrial fields such as medical and health, shoe-making, low temperature, packaging, plastics, automobiles, construction, and wood.

[0003] Modern society has great requirements for production rhythm. In the field of polyurethane adhesives, to achieve rapid curing, it is necessary to accelerate the reaction speed, but this will shorten the operating time of the adhesive. For some enterprises with higher production rhythm requirements, they need a longer operating time under normal temperature conditions for the convenience of workers' operations, and can achieve rapid shaping and curing under heating conditions, shortening the single-piece working hours. Currently, such adhesives are relatively rare in the market.

[0004] In the Chinese patent application solution with the publication number CN 111848920A, 800 parts of polymethylene polyphenyl isocyanate, 50 - 100 parts of diphenylmethane diisocyanate, 100 parts of tackifying resin, 600 parts of self-made waste PET recycled phthalic anhydride polyester, 350 parts of phthalic anhydride polyester, 60 parts of polyether, 80 parts of castor oil, organic solvents, 800 parts of plasticizer, modified amine, catalyst, and stabilizer are used as raw materials to prepare a thermosensitive polyurethane adhesive. However, this solution does not compare the reaction speeds at normal temperature and after heating, and whether it has thermosensitivity remains to be considered.

[0005] In view of this, the present invention is particularly proposed. Summary of the Invention

[0006] The object of the present invention is to provide a delayed thermosensitive two-component polyurethane adhesive and a preparation method thereof. This adhesive has a long operating time at normal temperature, a fast curing speed when heated to above 60°C, excellent bonding performance after curing, a wide range of bonding substrates, is applicable to wood, SMC, steel, rock wool board, etc., and the raw materials are widely available and environmentally friendly. After heating, it can significantly accelerate the production and curing rhythm and improve production efficiency.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] A delayed thermosensitive two-component polyurethane adhesive, which is prepared by mixing component A and component B in a mass ratio of 1-5:1. Among them, component A is a polyol prepared from the following raw materials by mass percentage, including:

[0009] Hydroxyl-terminated polyurethane prepolymer 20-48%, modified filler 30-58%, molecular sieve 5-15%, coupling agent 0.5-1.5%, crosslinking agent 1-5% and delayed thermosensitive catalyst 0.1-1%;

[0010] Component B uses polyisocyanate.

[0011] Preferably, in the above-mentioned adhesive, the hydroxyl-terminated polyurethane prepolymer is prepared from 70-90% of polyol and 10-30% of isocyanate by mass percentage. The polyol and isocyanate are added to a synthesis reaction kettle and reacted at 70-90 °C for 1.5-3 h to obtain the hydroxyl-terminated polyurethane prepolymer.

[0012] Preferably, in the above-mentioned adhesive, the polyol in component A uses a polyol with a functionality of 2-4 and a hydroxyl value of 50-340 mg / g (KOH);

[0013] The isocyanate in component A uses one or any several of MDI, polymeric MDI, carbodiimide-modified MDI, and HDI trimer.

[0014] Preferably, in the above-mentioned adhesive, the polyol uses one or more of soybean oil, castor oil, palm oil, and polyether polyol.

[0015] Preferably, in the above-mentioned adhesive, the modified filler uses one or more of modified calcium carbonate, modified talc powder, modified silica powder, and mica powder.

[0016] Preferably, in the above-mentioned adhesive, the molecular sieve uses one or any two of 3A or 4A molecular sieves.

[0017] The silane coupling agent uses one or any several of glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, aminopropyltriethoxysilane, and aminopropyltrimethoxysilane.

[0018] Preferably, in the above-mentioned adhesive, the crosslinking agent in component A uses one or any several of triethanolamine, trimethylolpropane, triisopropanolamine, and polyether polyol with a molecular weight of 200-600;

[0019] The delayed thermosensitive catalyst in component A uses one or any several of organometallic thermosensitive catalysts and amine thermosensitive catalysts.

[0020] A preparation method of the delayed thermosensitive two-component polyurethane adhesive according to the present invention comprises the following steps:

[0021] Preparing component A:

[0022] Take each raw material according to the formula of component A of the present invention. Use a high-speed dispersion kettle to mix the hydroxyl-terminated polyurethane prepolymer, modified filler, molecular sieve, coupling agent, crosslinking agent, and catalyst in the raw materials at a dispersion speed of 300-1000 r / min for 0.5-2 h. After mixing evenly, component A is obtained;

[0023] Compound: Mix the component A and the polyisocyanate as component B according to a mass ratio of 1-5:1 to obtain the delayed thermosensitive two-component polyurethane adhesive.

[0024] Preferably, in the above method, the hydroxyl-terminated polyurethane prepolymer is prepared by using 70-90% of polyol and 10-30% of isocyanate by mass percentage as raw materials. Add the polyol and isocyanate into a synthesis reaction kettle and react at 70-90 °C for 1.5-3 h to obtain the hydroxyl-terminated polyurethane prepolymer.

[0025] Compared with the prior art, the beneficial effects of the delayed thermosensitive two-component polyurethane adhesive and its preparation method provided by the present invention include:

[0026] By using a delayed thermosensitive catalyst as the catalyst of the two-component polyurethane adhesive, the reaction speed of the system at room temperature is slower, and the reaction speed increases rapidly after heating to above 60 °C. Especially when heated to above 100 °C, it can be cured within 70 s. The high-temperature reaction speed is much higher than that of ordinary catalysts. This adhesive is not only environmentally friendly, but also has excellent bonding performance, a wide range of bonding substrates and easily available raw materials, and is pollution-free to the environment and can be widely used in industries with a fast processing rhythm such as wood processing, construction, and automobiles. Specific embodiments

[0027] Combined with the specific content of the present invention below, the technical solutions in the embodiments of the present invention are described clearly and completely; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, which does not constitute a limitation to the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0028] First, the following explanations are given for the terms that may be used in this article:

[0029] The term "and / or" means that either or both of the two can be achieved. For example, X and / or Y means that it includes three cases: the case of "X" or "Y" and the case of "X and Y".

[0030] Descriptions with terms such as "comprising", "including", "containing", "having" or other similar semantics should be interpreted as non-exclusive inclusion. For example: including a certain technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction condition, processing condition, parameter, algorithm, signal, data, product or article, etc.) should be interpreted as not only including the explicitly listed certain technical feature element, but also including other technical feature elements well-known in the art that are not explicitly listed.

[0031] The term "consisting of" means excluding any technical feature element that is not explicitly listed. If this term is used in a claim, then this term will make the claim a closed type, making it not contain technical feature elements other than the explicitly listed ones, except for related conventional impurities. If this term only appears in a certain clause of a claim, then it only limits the elements explicitly listed in that clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0032] The term "parts by mass" represents the mass ratio relationship between multiple components. For example: if it is described that component X is x parts by mass and component Y is y parts by mass, then it means the mass ratio of component X to component Y is x:y; 1 part by mass can represent any mass. For example: 1 part by mass can be expressed as 1 kg or 3.1415926 kg, etc. The sum of the parts by mass of all components is not necessarily 100 parts, and it can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, ratios and percentages described in this article are all by mass.

[0033] When a concentration, temperature, pressure, size or other parameter is expressed in the form of a numerical range, this numerical range should be understood to specifically disclose all ranges formed by the pairing of any upper limit value, lower limit value and preferred value within this numerical range, regardless of whether this range is explicitly recorded; for example, if the numerical range "2 - 8" is recorded, then this numerical range should be interpreted as including ranges such as "2 - 7", "2 - 6", "5 - 7", "3 - 4 and 6 - 7", "3 - 5 and 7", "2 and 5 - 7", etc. Unless otherwise specified, the numerical ranges recorded in this article include both their end values and all integers and fractions within this numerical range.

[0034] The following provides a detailed description of the delayed thermosensitive two-component polyurethane adhesive and its preparation method provided by the present invention. The content not described in detail in the embodiments of the present invention belongs to the prior art well-known to those skilled in the art. For the conditions not specified in the embodiments of the present invention, they are carried out according to the conventional conditions in the art or the conditions recommended by the manufacturer. The reagents or instruments used in the embodiments of the present invention without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0035] An embodiment of the present invention provides a delayed thermosensitive two-component polyurethane adhesive, comprising:

[0036] Component A and Component B. When Component A and Component B are mixed in a mass ratio of 1-5:1, a delayed thermosensitive two-component polyurethane adhesive is obtained; wherein,

[0037] Component A is composed of 20-48% of a hydroxyl-terminated polyurethane prepolymer by mass percentage, 30-58% of a modified filler, 5-15% of a molecular sieve, 0.5-1.5% of a coupling agent, 1-5% of a crosslinking agent, and 0.1-1% of a delayed thermosensitive catalyst;

[0038] Preferably, the hydroxyl-terminated polyurethane prepolymer in the above Component A is prepared from 70-90% of a polyol and 10-30% of an isocyanate by mass percentage. The polyol and the isocyanate are added to a synthesis reaction kettle and reacted at 70-90°C for 1.5-3 h to obtain the hydroxyl-terminated polyurethane prepolymer.

[0039] As a preferred scheme, the polyol in the hydroxyl-terminated polyurethane prepolymer is one or more of soybean oil, castor oil, and palm oil polyether polyol, but is not limited to the above polyols. Any polyol with a functionality of 2-4 and a hydroxyl value of 35-340 mg / g can be used for the hydroxyl-terminated polyurethane prepolymer of Component A.

[0040] As a preferred scheme, the isocyanate in the hydroxyl-terminated polyurethane prepolymer is one or any several of MDI, polymeric MDI, carbodiimide-modified MDI, and HDI trimer.

[0041] As a preferred scheme, the above modified filler is one or any several of modified calcium carbonate, modified talc powder, modified silica powder, and mica powder.

[0042] As a preferred scheme, the above molecular sieve is one or any two of 3A or 4A molecular sieves.

[0043] As a preferred scheme, the above coupling agent is one or any several of epoxypropyltrimethoxysilane, epoxypropyltriethoxysilane, aminopropyltriethoxysilane, and aminopropyltrimethoxysilane.

[0044] As a preferred solution, the crosslinking agent in the above-mentioned component A is one or any combination of triethanolamine, trimethylolpropane, triisopropanolamine, and polyether polyol with a molecular weight of 200-600.

[0045] As a preferred solution, the delayed thermosensitive catalyst in the above-mentioned component A is one or any combination of organometallic thermosensitive catalysts and amine thermosensitive catalysts.

[0046] The embodiment of the present invention also provides a preparation method of the above-mentioned delayed thermosensitive two-component polyurethane adhesive, which includes the following steps:

[0047] Prepare component A:

[0048] Take each raw material in the formula for preparing component A, and use a high-speed dispersion kettle to mix the hydroxyl-terminated polyurethane prepolymer, modified filler, coupling agent, crosslinking agent, and delayed thermosensitive catalyst at a dispersion speed of 300-1000 r / min for 0.5-2 h. After mixing evenly, the component A of the delayed thermosensitive two-component polyurethane adhesive is obtained;

[0049] Component B uses polyisocyanate;

[0050] Compound: Mix the above-mentioned prepared component A and component B according to a mass ratio of 1-5:1 to obtain the delayed thermosensitive two-component polyurethane adhesive.

[0051] In summary, the delayed thermosensitive two-component polyurethane adhesive of the embodiment of the present invention has the following advantages:

[0052] By using one or more vegetable oil polyols such as soybean oil, castor oil, and palm oil polyether polyol in the hydroxyl-terminated polyurethane prepolymer in component A, the source is wide; this adhesive passes the RoHS and SVHC tests and is pollution-free; by adjusting the specific ratio of each component, the polyurethane adhesive prepared by the present invention has excellent bonding performance and can bond a wide range of substrates, including wood, metal, SMC, polyurethane foam, phenolic foam, glass fiber reinforced materials, etc.; due to the use of a delayed thermosensitive catalyst, this adhesive has excellent thermosensitive performance, the operation time at room temperature can reach more than 10 minutes, and it can achieve rapid curing after heating, especially it can complete curing within 70 seconds when the temperature rises above 100°C.

[0053] In order to more clearly show the technical solutions provided by the present invention and the technical effects produced, the following uses specific examples to describe in detail the delayed thermosensitive two-component polyurethane adhesive and its preparation method provided by the embodiment of the present invention.

[0054] Example 1

[0055] This embodiment provides a delayed thermosensitive two-component polyurethane adhesive, comprising: component A of polyol and component B of isocyanate. The component A comprises raw materials in the following weight percentages:

[0056] Prepare a hydroxyl-terminated polyurethane prepolymer:

[0057] Add 80% of refined castor oil and 20% of diphenylmethane diisocyanate into a synthesis reactor, and react at 80 °C for 3 h to obtain a hydroxyl-terminated polyurethane prepolymer;

[0058] Prepare component A: Mix 35% of the above-prepared hydroxyl-terminated polyurethane prepolymer, 49% of modified calcium carbonate, 5% of low-molecular polyether triol, 1% of fumed silica, 0.4% of a delayed thermosensitive catalyst, and 9.6% of molecular sieve in a high-speed dispersion kettle at a dispersion speed of 600 r / min for 1 h to obtain component A of the delayed thermosensitive two-component polyurethane adhesive;

[0059] Prepare component B: The raw material of component B is polymeric MDI;

[0060] Compound: Mix the above-prepared component A and component B in a mass ratio of 5:1 to obtain a delayed thermosensitive polyurethane adhesive.

[0061] Example 2

[0062] This embodiment provides a delayed thermosensitive two-component polyurethane adhesive, comprising: component A of polyol and component B of isocyanate. The component A comprises raw materials in the following weight percentages:

[0063] Prepare a hydroxyl-terminated polyurethane prepolymer:

[0064] Add 70% of refined castor oil and 30% of diphenylmethane diisocyanate into a synthesis reactor, and react at 80 °C for 3 h to obtain a hydroxyl-terminated polyurethane prepolymer;

[0065] Prepare component A: Mix 42% of the above-prepared hydroxyl-terminated polyurethane prepolymer, 41% of modified calcium carbonate, 5% of low-molecular polyether triol, 1% of fumed silica, 0.5% of a delayed thermosensitive catalyst, 0.5% of a coupling agent, and 10% of molecular sieve in a high-speed dispersion kettle at a dispersion speed of 600 r / min for 1 h to obtain component A of the delayed thermosensitive two-component polyurethane adhesive;

[0066] Prepare component B: The raw material of component B is polymeric MDI;

[0067] Compound: Mix the above-prepared component A and component B in a mass ratio of 4:1 to obtain a delayed thermosensitive polyurethane adhesive.

[0068] Example 3

[0069] This embodiment provides a delayed thermosensitive two-component polyurethane adhesive, comprising: a polyol A component and an isocyanate B component. The A component includes:

[0070] Prepare a hydroxyl-terminated polyurethane prepolymer:

[0071] Add 80% of refined castor oil and 20% of diphenylmethane diisocyanate into a synthesis reactor, and react at 80 °C for 3 h to obtain a hydroxyl-terminated polyurethane prepolymer;

[0072] Prepare the A component: Mix 35% of the above-prepared hydroxyl-terminated polyurethane prepolymer, 51.3% of modified calcium carbonate, 2% of low-molecular-weight polyether triol, 1% of fumed silica, 0.7% of a delayed thermosensitive catalyst, and 10% of molecular sieve in a high-speed dispersing kettle at 600 r / min for 1 h to obtain the A component of the delayed thermosensitive two-component polyurethane adhesive;

[0073] Prepare the B component: The raw material of the B component is polymeric MDI;

[0074] Compound: Mix the above-prepared A component and B component in a mass ratio of 5:1 to obtain a delayed thermosensitive polyurethane adhesive.

[0075] Example 4

[0076] This embodiment provides a delayed thermosensitive two-component polyurethane adhesive, comprising: a polyol A component and an isocyanate B component. The A component includes (the dosage of each raw material is in weight percentage):

[0077] Prepare a hydroxyl-terminated polyurethane prepolymer:

[0078] Add 50% of refined castor oil, 30% of polyether polyol (molecular weight 800), and 20% of polymeric MDI into a synthesis reactor, and react at 80 °C for 3 h to obtain a hydroxyl-terminated polyurethane prepolymer;

[0079] Prepare the A component: Mix 45% of the above-prepared hydroxyl-terminated polyurethane prepolymer, 40.4% of calcium carbonate, 5% of low-molecular-weight polyether triol, 1% of fumed silica, 1% of glycidoxypropyltrimethoxysilane, 0.6% of a catalyst, and 7% of molecular sieve in a high-speed dispersing kettle until evenly mixed to obtain the A component of the delayed thermosensitive two-component polyurethane adhesive;

[0080] Prepare the B component (the dosage of each raw material is in weight percentage): The B component raw material is prepared by mixing 90% of polymeric MDI and 10% of MDI50 evenly;

[0081] Compound: Mix the above-prepared A component and B component in a mass ratio of 3:1 to obtain a delayed thermosensitive polyurethane adhesive.

[0082] Comparative Example 1

[0083] A certain company currently has a commercially available delayed thermosensitive two-component polyurethane adhesive.

[0084] Comparative Example 2

[0085] Preparation of Component A:

[0086] By weight, 40 parts of vegetable oil polyol FH-3140, 55 parts of heavy calcium carbonate, and 5 parts of 4A molecular sieve were dispersed at high speed for 30 min under the condition of 2000 rmp, cooled to below 50 °C, and 0.05 part of dibutyltin dilaurate was added, and mixed evenly under the condition of 1000 rmp to obtain the Component A;

[0087] Component B is polymeric MDI;

[0088] Mix evenly according to the mass ratio of Component A:Component B of 5:1, make shear specimens and rubber blocks, cure for 7 days under the conditions of 25 ± 2 °C and 50 ± 5% RH, and test the tensile shear strength of the specimens and the hardness of the rubber blocks.

[0089] Table 1 shows the performance test results:

[0090]

[0091]

[0092] It can be seen from Table 1 above that the delayed thermosensitive two-component polyurethane adhesive of the present invention has excellent tensile shear strength, that is, it has good adhesion performance to the substrate, and can be quickly cured after heating.

[0093] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims. The information disclosed in the background art part of this article is only intended to deepen the understanding of the overall background art of the present invention, and should not be regarded as an admission or an indication in any form that this information constitutes the prior art known to those skilled in the art.

Claims

1. A delayed heat-sensitive two-component polyurethane adhesive, characterized in that: The adhesive is prepared by mixing component A and component B in a mass ratio of 1 to 5:1, wherein component A is a polyol prepared from the following raw materials in terms of mass percentage, including: 20-48% of terminal hydroxyl polyurethane prepolymer, 30-58% of modified filler, 5-15% of molecular sieve, 0.5-1.5% of coupling agent, 1-5% of cross-linking agent and 0.1-1% of delayed heat-sensitive catalyst; The B component is polyisocyanate.

2. The delayed heat-sensitive two-component polyurethane adhesive according to claim 1, characterized in that: The hydroxyl-terminated polyurethane prepolymer in the component A is prepared by adding 70-90% of polyol and 10-30% of isocyanate by mass into a synthesis reactor and reacting at 70-90° C. for 1.5-3 hours.

3. The delayed heat-sensitive two-component polyurethane adhesive according to claim 2, characterized in that: The polyol in the hydroxy polyurethane prepolymer is a polyol with a functionality of 2 to 4 and a hydroxyl value of 35 to 340 mg / g; The isocyanate in the hydroxy polyurethane prepolymer is one or any combination of MDI, polymeric MDI, carbodiimide-modified MDI, and HDI trimer.

4. The delayed heat-sensitive two-component polyurethane adhesive according to claim 2 or 3, characterized in that: The polyol is one or more of soybean oil, castor oil, palm oil and polyether polyol.

5. The delayed heat-sensitive two-component polyurethane adhesive according to any one of claims 1 to 3, characterized in that: The modified filler in the component A is one or more of modified calcium carbonate, modified talc, modified silica powder and mica powder.

6. The delayed heat-sensitive two-component polyurethane adhesive according to any one of claims 1 to 3, characterized in that: The silane coupling agent in the component A is one or any combination of epoxypropyltrimethoxysilane, epoxypropyltriethoxysilane, aminopropyltriethoxysilane and aminopropyltrimethoxysilane.

7. A vegetable oil-based flame-retardant two-component polyurethane adhesive according to any one of claims 1 to 3, characterized in that: The crosslinking agent in the component A is one or any combination of triethanolamine, trimethylolpropane, triisopropanolamine, and polyether polyol with a molecular weight of 200 to 600.

8. A vegetable oil-based flame-retardant two-component polyurethane adhesive according to any one of claims 1 to 3, characterized in that: The delayed heat-sensitive catalyst in the component A is one or any combination of an organic metal catalyst and an amine catalyst.

9. A method for preparing the delayed heat-sensitive two-component polyurethane adhesive according to any one of claims 1 to 8, characterized in that: The following steps are involved: Preparation of component A: The raw materials are taken according to the formulation of component A according to any one of claims 1 to 8, and the hydroxyl-terminated polyurethane prepolymer, modified filler, molecular sieve, crosslinking agent and delayed thermal-sensitive catalyst in the raw materials are uniformly mixed using a high-speed dispersing kettle at a dispersing speed of 300 to 1000 r / min to obtain component A; Compounding: The component A and the polyisocyanate as the component B are mixed in a mass ratio of 1 to 5:1 to prepare a delayed heat-sensitive two-component polyurethane adhesive.

10. The method for preparing the delayed heat-sensitive two-component polyurethane adhesive according to claim 9, characterized in that: The hydroxy polyurethane prepolymer is prepared by taking 70-90% of polyol and 10-30% of isocyanate as raw materials by mass percentage, adding vegetable oil polyol and isocyanate into a synthesis reactor, and reacting at 70-90° C. for 1.5-3 hours to obtain a terminal hydroxy polyurethane prepolymer.

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