Two-component polyurethane elastic adhesive and preparation method thereof

Abstract

The invention discloses a two-component polyurethane elastic adhesive and a preparation method thereof, and belongs to the field of polyurethane adhesives. The adhesive comprises a component A and a component B, wherein the component A comprises hydroxyl-terminated polybutadiene, polyester or polyether polyol, a micromolecular hydroxyl compound, a chain extender, an antioxidant, a catalyst, a first filler, a first water removal agent and a pigment; the component B comprises an isocyanate-terminated polyurethane prepolymer, first isocyanate, a second dewatering agent, a second filler, a coupling agent and a thixotropic agent; and the isocyanate-terminated polyurethane prepolymer in the component B is prepared from hydroxyl-terminated polybutadiene or polyester polyol and isocyanate. The component A and the component B are uniformly mixed according to the volume ratio of 1: 1 for use. The adhesive has the advantages of wide adhesion base materials, favorable elasticity, excellent low-temperature resistance, excellent aging resistance, excellent heat sensitivity and favorable resistance to heat, damp heat and water.

Description

Technical Field

[0001] This invention relates to the field of polyurethane adhesives, specifically to a two-component polyurethane elastic adhesive and its preparation method. Background Technology

[0002] Elastic adhesives are adhesives that, after being cured by a certain method, possess rubber elasticity and a certain bonding strength. Compared with rigid adhesives, elastic adhesives have the following advantages: (1) Elastic adhesives have better deformation capacity, and the joint can withstand greater deformation, thus adapting to the expansion, contraction, and deformation of the connecting materials; (2) Elastic adhesives have better impact and vibration resistance. Due to the characteristics of elastic adhesive materials, the joint can absorb and disperse the energy of impact and vibration, thereby reducing the impact on the joint; (3) Elastic adhesives have better sealing performance, and the joint can provide a better sealing effect, preventing the penetration of substances such as liquids, gases, and dust.

[0003] With the global energy crisis and increasing environmental awareness, lightweighting technology has become a crucial trend in the automotive industry. Lightweighting not only improves fuel economy and reduces emissions but also enhances vehicle performance and handling. Experiments have shown that a 10% reduction in vehicle weight can improve fuel efficiency by 6%–8%; a 100 kg reduction in curb weight can reduce fuel consumption by 0.3–0.6 liters per 100 kilometers; and a 1% reduction in weight can reduce fuel consumption by 0.7%. Currently, due to the needs of environmental protection and energy conservation, lightweighting has become a global trend in automotive development.

[0004] Automotive exterior components include bumpers, hoods, grilles, headlights, wheels, tailgates, spoilers, etc., and involve polymer materials such as PP, ABS, ASA, PCABS, and SMC. These substrates have significant differences in polarity, requiring high-quality adhesives. Traditional connection technologies for exterior components, such as welding and riveting, have the disadvantage of adding extra weight to the vehicle body when used to connect dissimilar or non-metallic materials.

[0005] The two-component polyurethane adhesive disclosed in Chinese patent CN119144263A has a hardness >50 Shore D and an elongation at break <150% after curing. The adhesive has poor elasticity and the joint cannot withstand large deformations.

[0006] Therefore, developing a polyurethane elastic adhesive that can be used for bonding automotive exterior parts and meets the requirements of withstanding large deformations is a technical problem that needs to be solved.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a two-component polyurethane elastic adhesive and its preparation method, which can withstand large deformations and meet the bonding requirements of automotive exterior parts, thereby solving the problems existing in the prior art.

[0009] The objective of this invention is achieved through the following technical solution: A two-component polyurethane elastic adhesive, comprising components A and B in a 1:1 volume ratio; wherein... Component A is a polyol component made from the following raw materials by mass percentage: 15-40% hydroxyl-terminated polybutadiene, 2-15% polyester polyol or polyether polyol, 2-10% small molecule hydroxyl compound, 1-5% chain extender, 0.1-1% antioxidant, 0.1-1% catalyst, 20-45% first filler, 1-10% first dehydrating agent, and 0.05-1% pigment; Component B is an isocyanate component made from the following raw materials by mass percentage: 30-60% isocyanate-terminated polyurethane prepolymer, 5-15% first isocyanate, 0.1-1% second dehydrating agent, 30-50% second filler, 0.5-5% coupling agent, and 0.5-5% thixotropic agent.

[0010] Preferably, in the above adhesive, the number-average molecular weight of the hydroxyl-terminated polybutadiene in component A is 1000-8000 and the functionality is 2-4.

[0011] Preferably, in the above adhesive, the number average molecular weight of the polyester polyol or polyether polyol in component A is 1000-5000, and the functionality is 2-4.

[0012] Preferably, in the above adhesive, the small molecule hydroxyl compound in component A is at least one selected from diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, dodecyl alcohol, and 2-ethyl-1,3-hexanediol.

[0013] Preferably, in the above adhesive, the chain extender in component A is at least one selected from ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, and 2,2,4-trimethyl-1,3-pentanediol.

[0014] Preferably, in the above adhesive, the antioxidant in component A is a hindered phenolic antioxidant and an amine antioxidant; The catalyst is at least one of organometallic compounds and amine compounds; The first filler is at least one of calcium carbonate, kaolin, wollastonite powder, talc powder, mica powder, titanium dioxide, silica fume, alumina, aluminum hydroxide, barium sulfate, and calcium sulfate. The first dehydrating agent is at least one of 3A activated molecular sieve, 4A activated molecular sieve, vinyltrimethoxysilane, and oxazolidine dehydrating agent; The pigment is at least one of carbon black, aniline black, and iron black.

[0015] Preferably, in the above-mentioned adhesive, the isocyanate-terminated polyurethane prepolymer in component B is made from 20-70% polyol with a moisture content of less than 500 ppm and 30-80% isocyanate as raw materials. The polyol and isocyanate are added to a synthesis reactor and reacted at 70-90°C for 1.5-3 hours to obtain an isocyanate-terminated polyurethane prepolymer with an isocyanate content of 5-30%.

[0016] Preferably, in the above-mentioned adhesive, the polyol used in the isocyanate-terminated polyurethane prepolymer of component B is at least one of hydroxyl-terminated polybutadiene with a number average molecular weight of 1000-8000 and a functionality of 2-4, and polyester polyol with a number average molecular weight of 1000-5000 and a functionality of 2-4. The isocyanate used is at least one of toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, isoflurone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexanediamine diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate.

[0017] Preferably, in the above adhesive, the second dehydrating agent in component B is p-toluenesulfonyl isocyanate; The second filler is at least one of calcium carbonate, kaolin, wollastonite powder, talc powder, mica powder, titanium dioxide, silica powder, alumina, aluminum hydroxide, barium sulfate, and calcium sulfate. The coupling agent is at least one of γ-glycidoxypropyltrimethoxysilane and vinyltrimethoxysilane; The thixotropic agent is at least one of fumed silica and organobentonite. The first isocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, isoflurone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexanediamine diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate.

[0018] A method for preparing the two-component polyurethane elastic adhesive of the present invention includes taking raw materials of components A and B according to the formulation of the two-component polyurethane elastic adhesive of the present invention, and preparing components A and B respectively, comprising: Preparation of component A: The hydroxyl-terminated polybutadiene, polyester polyol or polyether polyol, small molecule hydroxy compound, chain extender, antioxidant, catalyst, first filler, first dehydrating agent and pigment in component A are mixed in a high-speed dispersion kettle at a dispersion speed of 300-1000 rpm and a stirring speed of 15-60 rpm for 0.5-3 hours. After the mixture is uniform, component A is obtained. Preparation of component B: The isocyanate-terminated polyurethane prepolymer, first isocyanate, second dehydrating agent, second filler, coupling agent and thixotropic agent in component B are mixed in a high-speed dispersion vessel at a dispersion speed of 300-1000 rpm and a stirring speed of 15-60 rpm for 0.5-3 hours. After uniform mixing, component B is obtained. The two-component polyurethane elastic adhesive is obtained by mixing the above-prepared component A and component B in a volume ratio of 1:1.

[0019] Compared with the prior art, the two-component polyurethane elastic adhesive and its preparation method provided by the present invention have the following advantages: (1) This two-component polyurethane elastic adhesive is solvent-free, safe and environmentally friendly, and harmless to human health.

[0020] (2) The two-component polyurethane elastic adhesive has a hardness of 55-70 Shore A after curing, a tensile strength of 3-5 MPa, and an elongation at break of 300-400%. It can withstand a temperature range of -40℃ to 90℃. At -40℃, the elongation can still reach more than 300%. The adhesive still has good toughness and elasticity at temperatures above -40℃. It can effectively absorb the stress caused by vibration and temperature difference during vehicle operation and avoid cracking or falling off of exterior parts due to differences in the thermal expansion coefficient of the substrate.

[0021] (3) This two-component polyurethane elastic adhesive has a wide range of bonding applications and good adhesion to different types of substrates. Specifically, it has good adhesion to PP, SMC and other substrates after flame treatment or plasma treatment; it can be directly bonded to plastic substrates such as PC, PCABS, ABS, ASA, PCPET, PMMA and others without flame, plasma or primer treatment; and it can be directly bonded to metal materials without grinding.

[0022] (4) This two-component polyurethane elastic adhesive has excellent heat sensitivity. The reaction rate is significantly accelerated when heated to 60-90℃. The shear strength is >0.5MPa when hot-pressed for 3 minutes at 80℃.

[0023] (5) The two-component polyurethane elastic adhesive has excellent aging resistance, specifically, the bonding strength does not decrease significantly after aging under conditions such as high temperature, high and low temperature, humid heat, and soaking in water. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific content of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, which do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0025] First, the following explanations are provided for the terms that may be used in this article: The term "and / or" means that either or both can be achieved simultaneously. For example, X and / or Y means that it includes both "X" or "Y" as well as the three cases of "X and Y".

[0026] The terms "comprising," "including," "containing," "having," or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.) should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0027] The term "composed of" excludes any technical features not expressly listed. When used in a claim, it closes the claim to exclude all technical features other than those expressly listed, except for associated conventional impurities. If the term appears only in a clause of a claim, it limits the claim to the elements expressly listed in that clause; elements recited in other clauses are not excluded from the overall claim.

[0028] The term "parts by mass" indicates the mass ratio between multiple components. For example, if component X is described as x parts by mass and component Y as y parts by mass, then the mass ratio of component X to component Y is x:y. One part by mass can represent any mass; for example, one 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; it can be greater than 100 parts, less than 100 parts, or equal to 100 parts. Unless otherwise stated, parts, proportions, and percentages mentioned herein are all measured by mass.

[0029] When concentration, temperature, pressure, size, or other parameters are expressed as numerical ranges, such ranges should be understood to specifically disclose all ranges formed by any pairing of upper limits, lower limits, or preferred values ​​within that range, regardless of whether the range is explicitly stated; for example, if the numerical range "2 to 8" is stated, then that range should be interpreted to include ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise stated, the numerical ranges described herein include both their endpoints and all integers and fractions within that range.

[0030] The solution provided by this invention will be described in detail below. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they shall be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the embodiments of this invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0031] This invention provides a two-component polyurethane elastic adhesive, consisting of two components, A and B, which are mixed in a volume ratio of 1:1.

[0032] Component A is a polyol component made from the following raw materials by mass percentage: 15-40% hydroxyl-terminated polybutadiene, 2-15% polyester polyol or polyether polyol, 2-10% small molecule hydroxyl compound, 1-5% chain extender, 0.1-1% antioxidant, 0.1-1% catalyst, 20-45% filler, 1-10% dehydrating agent, and 0.05-1% pigment; Component B is an isocyanate component made from the following raw materials by mass percentage: 30-60% isocyanate-terminated polyurethane prepolymer, 5-15% isocyanate, 0.1-1% dehydrating agent, 30-50% filler, 0.5-5% coupling agent, and 0.5-5% thixotropic agent.

[0033] In some specific embodiments, the number-average molecular weight of the hydroxyl-terminated polybutadiene in component A of the above-mentioned adhesive is 1000-8000 and the functionality is 2-4. The number-average molecular weight of the hydroxyl-terminated polybutadiene refers to the molecular weight obtained by weighting the number of molecules of different molecular weight components in the polymer material. The number-average molecular weight of the hydroxyl-terminated polybutadiene is within this range, which can make the cured product have excellent mechanical properties, hydrolysis resistance, electrical insulation, acid and alkali resistance, aging resistance and adhesion properties.

[0034] In some specific embodiments, the number average molecular weight of the polyester / polyether polyol in component A of the above-mentioned adhesive is 1000-5000, and the functionality is 2-4.

[0035] In some specific embodiments, the small molecule hydroxyl compound in component A of the above-mentioned adhesive includes at least one of diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, dodecyl alcohol, and 2-ethyl-1,3-hexanediol.

[0036] In some specific embodiments, the chain extender in component A of the above-mentioned adhesive includes at least one selected from ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, and 2,2,4-trimethyl-1,3-pentanediol.

[0037] In some specific embodiments, the antioxidants in component A of the above-mentioned adhesive are hindered phenolic antioxidants and amine antioxidants.

[0038] In some specific embodiments, the catalyst in component A of the above-mentioned adhesive is at least one of organometallic compounds and amine compounds.

[0039] In some specific embodiments, the filler in component A of the above-mentioned adhesive is at least one of calcium carbonate, kaolin, wollastonite powder, talc powder, mica powder, titanium dioxide, silica fume, alumina, aluminum hydroxide, barium sulfate, and calcium sulfate.

[0040] In some specific embodiments, the dehydrating agent in component A of the above-mentioned adhesive is at least one of 3A activated molecular sieve, 4A activated molecular sieve, vinyltrimethoxysilane, and oxazolidine dehydrating agent.

[0041] In some specific embodiments, the pigment in component A of the above-mentioned adhesive is at least one of carbon black, aniline black, iron black, etc.

[0042] In some specific embodiments, the isocyanate-terminated polyurethane prepolymer used in component B of the above-mentioned adhesive is made from 20-70% polyol with a moisture content of less than 500 ppm and 30-80% isocyanate as raw materials. The polyol and isocyanate are added to a synthesis reactor and reacted at 70-90°C for 1.5-3 hours to obtain the isocyanate-terminated polyurethane prepolymer with an isocyanate content of 5-30%.

[0043] In some specific embodiments, the polyol used in the isocyanate-terminated polyurethane prepolymer of the above-mentioned adhesive component B is at least one of hydroxyl-terminated polybutadiene with a number average molecular weight of 1000-8000 and a functionality of 2-4, and polyester polyol with a number average molecular weight of 1000-5000 and a functionality of 2-4.

[0044] In some specific embodiments, the isocyanate used in the isocyanate-terminated polyurethane prepolymer of the above-mentioned adhesive component B and the first isocyanate used alone are both toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, isoflurone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexanediamine diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate.

[0045] In some specific embodiments, the dehydrating agent in component B of the above-mentioned adhesive is p-toluenesulfonyl isocyanate.

[0046] In some specific embodiments, the filler in component B of the adhesive is at least one selected from calcium carbonate, kaolin, wollastonite powder, talc powder, mica powder, titanium dioxide, silica fume, alumina, aluminum hydroxide, barium sulfate, and calcium sulfate.

[0047] Preferably, the coupling agent in component B is at least one of γ-glycidoxypropyltrimethoxysilane and vinyltrimethoxysilane.

[0048] Preferably, the thixotropic agent in component B is at least one of fumed silica and organobentonite.

[0049] This invention also provides a method for preparing the above-mentioned delayed-heat-sensitive two-component polyurethane adhesive, comprising the following steps: Take the raw materials of components A and B according to the above formula, and prepare components A and B respectively. Preparation of component A: The hydroxyl-terminated polybutadiene, polyester polyol or polyether polyol, small molecule hydroxy compound, chain extender, antioxidant, catalyst, first filler, first dehydrating agent and pigment in component A are mixed in a high-speed dispersion kettle at a dispersion speed of 300-1000 rpm and a stirring speed of 15-60 rpm for 0.5-3 hours. After the mixture is uniform, component A is obtained. Preparation of component B: The isocyanate-terminated polyurethane prepolymer, first isocyanate, second dehydrating agent, second filler, coupling agent and thixotropic agent in component B are mixed in a high-speed dispersion vessel at a dispersion speed of 300-1000 rpm and a stirring speed of 15-60 rpm for 0.5-3 hours. After uniform mixing, component B is obtained.

[0050] To more clearly demonstrate the technical solution and its effects provided by the present invention, the following detailed description of the solution provided by the embodiments of the present invention is provided with reference to specific examples.

[0051] Example 1 This embodiment provides a two-component polyurethane elastic adhesive, comprising: a polyol component A and an isocyanate component B, including: Table 1 shows the raw materials and dosages of component A in Example 1. .

[0052] Table 2 shows the raw materials and dosages of component B in Example 1. .

[0053] The isocyanate-terminated polyurethane prepolymer in component B above is prepared as follows: First, the hydroxyl-terminated polybutadiene is dehydrated at 110°C to reduce the moisture content to below 500 ppm, then cooled to 40°C, and then isocyanate is added and mixed evenly. The mixture is then heated to 80°C and stirred for 2 hours to obtain the isocyanate-terminated polyurethane prepolymer. The isocyanate is a polymethylene polyphenyl polyisocyanate, and the hydroxyl-terminated polybutadiene has a hydroxyl value of 56 mg KOH / g.

[0054] The preparation method of the two-component polyurethane elastic adhesive in this embodiment is as follows: Preparation of component A: Mix the raw materials in the above component A formula using a high-speed dispersion vessel at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 hours to obtain component A; Preparation of Component B: Mix the raw materials in the above Component B formula in a high-speed dispersion vessel at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 hours to obtain Component B.

[0055] The polyurethane elastic adhesive of this embodiment is obtained by mixing component A and component B at a volume ratio of 1:1.

[0056] Example 2 This embodiment provides a two-component polyurethane elastic adhesive, comprising: a polyol component A and an isocyanate component B, including: Table 3 shows the raw materials and dosages of component A in Example 2. .

[0057] Table 4 shows the raw materials and dosages of component B in Example 2. .

[0058] The isocyanate-terminated polyurethane prepolymer in component B above is prepared as follows: First, the polyester polyol is dehydrated at 110°C to reduce the moisture content to below 500 ppm, then cooled to 40°C, and then isocyanate is added and mixed evenly. The mixture is then heated to 80°C and stirred for 2 hours to obtain the isocyanate-terminated polyurethane prepolymer. The isocyanate is polymethylene polyphenyl polyisocyanate, and the polyester polyol is 56 mg KOH / g.

[0059] The preparation method of the two-component polyurethane elastic adhesive in this embodiment is as follows: Preparation of component A: The raw materials in the above component A formulation are mixed in a high-speed dispersion vessel at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h to obtain component A of the two-component polyurethane elastic adhesive. Preparation of component B: The raw materials in the above component B formulation are mixed in a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h to obtain component B of the two-component polyurethane elastic adhesive. The polyurethane elastic adhesive of this embodiment is obtained by mixing component A and component B at a volume ratio of 1:1.

[0060] Example 3 This embodiment provides a two-component polyurethane elastic adhesive, comprising: a polyol component A and an isocyanate component B, including: Table 5 shows the raw materials and dosages of component A in Example 3. .

[0061] Table 6 shows the raw materials and dosages of component B in Example 3. .

[0062] The isocyanate-terminated polyurethane prepolymer in component B above is prepared as follows: First, the hydroxyl-terminated polybutadiene is dehydrated at 110°C to reduce the moisture content to below 500 ppm, then cooled to 40°C, and then isocyanate is added and mixed evenly. The mixture is then heated to 80°C and stirred for 2 hours to obtain the isocyanate-terminated polyurethane prepolymer. The isocyanate is a polymethylene polyphenyl polyisocyanate, and the hydroxyl-terminated polybutadiene has a hydroxyl value of 56 mg KOH / g.

[0063] The preparation method of the two-component polyurethane elastic adhesive in this embodiment is as follows: Preparation of component A: The raw materials in the above component A formulation are mixed in a high-speed dispersion vessel at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h to obtain component A of the two-component polyurethane elastic adhesive. Preparation of component B: The raw materials in the above component B formulation are mixed in a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h to obtain component B of the two-component polyurethane elastic adhesive. The polyurethane elastic adhesive of this embodiment is obtained by mixing component A and component B at a volume ratio of 1:1.

[0064] Example 4 This embodiment provides a two-component polyurethane elastic adhesive, comprising: a polyol component A and an isocyanate component B, including: Table 7 lists the raw materials and dosages of component A in Example 4. .

[0065] Table 8 shows the raw materials and dosages of component B in Example 4. .

[0066] The isocyanate-terminated polyurethane prepolymer in component B above is prepared as follows: First, the polyester polyol is dehydrated at 110°C to reduce the moisture content to below 500 ppm, then cooled to 40°C, and then isocyanate is added and mixed evenly. The mixture is then heated to 80°C and stirred for 2 hours to obtain the isocyanate-terminated polyurethane prepolymer. The isocyanate is polymethylene polyphenyl polyisocyanate, and the polyester polyol is 56 mg KOH / g.

[0067] Preparation of Component A: Mix the raw materials in the above Component A formulation according to the mass ratio using a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h to obtain Component A of the two-component polyurethane elastic adhesive. Preparation of component B: The raw materials in the above component B formulation are mixed in a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h according to the mass ratio to obtain component B of the two-component polyurethane elastic adhesive. The polyurethane elastic adhesive of this embodiment is obtained by mixing component A and component B at a volume ratio of 1:1.

[0068] Comparative Example 1 This comparative example provides a two-component polyurethane elastic adhesive, comprising: a polyol component A and an isocyanate component B, including: Table 9 shows the raw materials and dosages of component A in Comparative Example 1. .

[0069] Table 10 shows the raw materials and dosages of component B in Comparative Example 1. .

[0070] The isocyanate-terminated polyurethane prepolymer in component B above is prepared as follows: First, the hydroxyl-terminated polybutadiene is dehydrated at 110°C to reduce the moisture content to below 500 ppm, then cooled to 40°C, and then isocyanate is added and mixed evenly. The mixture is then heated to 80°C and stirred for 2 hours to obtain the isocyanate-terminated polyurethane prepolymer. The isocyanate is a polymethylene polyphenyl polyisocyanate, and the hydroxyl-terminated polybutadiene has a hydroxyl value of 56 mg KOH / g.

[0071] The preparation method of the two-component polyurethane elastic adhesive in this comparative example is as follows: Preparation of Component A: Mix the raw materials in the above Component A formulation according to the mass ratio using a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h to obtain Component A of the two-component polyurethane elastic adhesive. Preparation of component B: The raw materials in the above component B formulation are mixed in a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h according to the mass ratio to obtain component B of the two-component polyurethane elastic adhesive. The polyurethane elastic adhesive of this comparative example is obtained by mixing component A and component B at a volume ratio of 1:1.

[0072] Comparative Example 2 This embodiment provides a two-component polyurethane elastic adhesive, comprising: a polyol component A and an isocyanate component B, including: Table 11 shows the raw materials and amounts of component A in Comparative Example 2. .

[0073] Table 12 shows the raw materials and dosages of component B in Comparative Example 2. .

[0074] The isocyanate-terminated polyurethane prepolymer in component B above is prepared as follows: First, the hydroxyl-terminated polybutadiene is dehydrated at 110°C to reduce the moisture content to below 500 ppm, then cooled to 40°C, and then isocyanate is added and mixed evenly. The mixture is then heated to 80°C and stirred for 2 hours to obtain the isocyanate-terminated polyurethane prepolymer. The isocyanate is a polymethylene polyphenyl polyisocyanate, and the hydroxyl-terminated polybutadiene has a hydroxyl value of 56 mg KOH / g.

[0075] The preparation method of the two-component polyurethane elastic adhesive in this comparative example is as follows: Preparation of Component A: Mix the raw materials in the above Component A formulation according to the mass ratio using a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h to obtain Component A of the two-component polyurethane elastic adhesive. Preparation of component B: The raw materials in the above component B formulation are mixed in a high-speed dispersion kettle at a dispersion speed of 600 rpm and a stirring speed of 30 rpm for 1.5 h according to the mass ratio to obtain component B of the two-component polyurethane elastic adhesive. The polyurethane elastic adhesive of this comparative example is obtained by mixing component A and component B at a volume ratio of 1:1.

[0076] Performance testing: The components A and B prepared in Examples 1-4, as well as Comparative Examples 1 and 2, were mixed uniformly at a volume ratio of 1:1. Basic performance tests and substrate adhesion tests were then conducted. The substrates used for adhesion tests included PP, SMC, PPLGF40, PCABS, ABS, ASA, PCPET, and PMMA. PP, SMC, and PPLGF40 substrates were flame-treated to a dyne value of 46 or higher. The surfaces of PCABS, ABS, ASA, PCPET, and PMMA substrates were wiped with alcohol to remove surface oil and dust. The treated substrates were bonded together using adhesive, and tests were conducted after complete curing.

[0077] Table 13 shows the basic performance tests of the two-component polyurethane elastic adhesives in each embodiment and comparative example. .

[0078] Table 14 shows the results of the two-component polyurethane elastic adhesives in each embodiment and comparative example. Bonding of different substrates (room temperature shear strength) .

[0079] Table 15 shows the results of the two-component polyurethane elastic adhesives in each embodiment and comparative example. Bonding of different substrates (aging at 90℃ for 336 hours) .

[0080] Table 16 shows the results of the two-component polyurethane elastic adhesives in each embodiment and comparative example. Bonding of different substrates (immersion in water at 40℃ for 240 hours) .

[0081] Table 17 shows the effects of the two-component polyurethane elastic adhesives in each embodiment and comparative example. Bonding of different substrates (aging at 70℃ and 95%RH for 168 hours) .

[0082] Table 18 shows the results of the two-component polyurethane elastic adhesives in each embodiment and comparative example. Bonding of different substrates (shear strength at -40℃) .

[0083] As shown in Table 13, the two-component polyurethane elastic adhesive prepared by the present invention has a solid content of over 99% after curing, tensile strength > 3 MPa, elongation at break > 300%, shear strength > 3 MPa, and shear strength > 0.5 MPa after hot pressing at 80℃ for 3 min.

[0084] As can be seen from Tables 14 to 18, the two-component polyurethane adhesive provided by the present invention has a wide range of bonding substrates. In particular, it can directly bond substrates such as PCABS, ASA, ABS, PCPET, and PMMA without flame, plasma, or primer treatment. Furthermore, it still has good adhesion after heat aging, damp heat aging, and water immersion aging, and the bonding strength basically does not decrease.

[0085] In summary, the two-component polyurethane adhesive prepared by the present invention has the following advantages: (1) it has a wide range of adhesive substrates and good adhesion to plastic, metal and other substrates; (2) it has good elasticity and excellent low temperature resistance; (3) it has excellent heat sensitivity, with a shear strength of >0.5MPa after pressing at 80℃ for 3min; (4) it has excellent aging resistance and good resistance to heat, humid heat and water.

[0086] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A two-component polyurethane elastic adhesive, characterized in that, This adhesive is composed of two components, A and B, in a 1:1 volume ratio; wherein... Component A is a polyol component made from the following raw materials by mass percentage: 15-40% hydroxyl-terminated polybutadiene, 2-15% polyester polyol or polyether polyol, 2-10% small molecule hydroxyl compound, 1-5% chain extender, 0.1-1% antioxidant, 0.1-1% catalyst, 20-45% first filler, 1-10% first dehydrating agent, and 0.05-1% pigment; the polyol is a polyester polyol or a polyether polyol. Component B is an isocyanate component made from the following raw materials by mass percentage: 30-60% isocyanate-terminated polyurethane prepolymer, 5-15% first isocyanate, 0.1-1% second dehydrating agent, 30-50% second filler, 0.5-5% coupling agent, and 0.5-5% thixotropic agent.

2. The two-component polyurethane elastic adhesive according to claim 1, characterized in that, The number-average molecular weight of the hydroxyl-terminated polybutadiene in component A is 1000–8000, and its functionality is 2–4.

3. The two-component polyurethane elastic adhesive according to claim 1, characterized in that, The number-average molecular weight of the polyester polyol or polyether polyol in component A is 1000-5000, and the functionality is 2-4.

4. The two-component polyurethane elastic adhesive according to claim 1, characterized in that, The small molecule hydroxyl compound in component A is at least one of diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, dodecyl alcohol, and 2-ethyl-1,3-hexanediol.

5. The two-component polyurethane elastic adhesive according to claim 1, characterized in that, The chain extender in component A is at least one selected from ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, and 2,2,4-trimethyl-1,3-pentanediol.

6. The two-component polyurethane elastic adhesive according to any one of claims 1-5, characterized in that, The antioxidants in component A are hindered phenolic antioxidants and amine antioxidants; The catalyst is at least one of organometallic compounds and amine compounds; The first filler is at least one of calcium carbonate, kaolin, wollastonite powder, talc powder, mica powder, titanium dioxide, silica fume, alumina, aluminum hydroxide, barium sulfate, and calcium sulfate. The first dehydrating agent is at least one of 3A activated molecular sieve, 4A activated molecular sieve, vinyltrimethoxysilane, and oxazolidine dehydrating agent; The pigment is at least one of carbon black, aniline black, and iron black.

7. The two-component polyurethane elastic adhesive according to any one of claims 1-5, characterized in that, The isocyanate-terminated polyurethane prepolymer in component B is prepared from polyols with a moisture content of less than 500 ppm (20-70%) and isocyanates (30-80%). The polyols and isocyanates are added to a synthesis reactor and reacted at 70-90°C for 1.5-3 hours to obtain an isocyanate-terminated polyurethane prepolymer with an isocyanate content of 5-30%.

8. The two-component polyurethane elastic adhesive according to claim 7, characterized in that, In the isocyanate-terminated polyurethane prepolymer of component B, the polyol used is at least one of hydroxyl-terminated polybutadiene with a number average molecular weight of 1000-8000 and a functionality of 2-4, and polyester polyol with a number average molecular weight of 1000-5000 and a functionality of 2-4. The isocyanate used is at least one of toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, isoflurone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexanediamine diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate.

9. The two-component polyurethane elastic adhesive according to any one of claims 1-5, characterized in that, In component B, the second dehydrating agent is p-toluenesulfonyl isocyanate; The second filler is at least one of calcium carbonate, kaolin, wollastonite powder, talc powder, mica powder, titanium dioxide, silica powder, alumina, aluminum hydroxide, barium sulfate, and calcium sulfate. The coupling agent is at least one of γ-glycidoxypropyltrimethoxysilane and vinyltrimethoxysilane; The thixotropic agent is at least one of fumed silica and organobentonite. The first isocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, isoflurone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexanediamine diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate.

10. A method for preparing the two-component polyurethane elastic adhesive according to any one of claims 1-9, characterized in that, The formulation of the two-component polyurethane elastic adhesive according to any one of claims 1-9 involves taking the raw materials of components A and B, and preparing components A and B respectively, including: Preparation of component A: The hydroxyl-terminated polybutadiene, polyester polyol or polyether polyol, small molecule hydroxy compound, chain extender, antioxidant, catalyst, first filler, first dehydrating agent and pigment in component A are mixed in a high-speed dispersion kettle at a dispersion speed of 300-1000 rpm and a stirring speed of 15-60 rpm for 0.5-3 hours. After the mixture is uniform, component A is obtained. Preparation of component B: The isocyanate-terminated polyurethane prepolymer, first isocyanate, second dehydrating agent, second filler, coupling agent and thixotropic agent in component B are mixed in a high-speed dispersion vessel at a dispersion speed of 300-1000 rpm and a stirring speed of 15-60 rpm for 0.5-3 hours. After uniform mixing, component B is obtained. The two-component polyurethane elastic adhesive is obtained by mixing the above-prepared component A and component B in a volume ratio of 1:1.