CN110669469B

CN110669469B - Two-component polyurethane structural adhesive and preparation method and application thereof

Info

Publication number: CN110669469B
Application number: CN201911003413.4A
Authority: CN
Inventors: 徐亚芳
Original assignee: Gelitai New Materials Technology Suzhou Co ltd
Current assignee: Gelitai New Materials Technology Suzhou Co ltd
Priority date: 2019-10-22
Filing date: 2019-10-22
Publication date: 2022-04-12
Anticipated expiration: 2039-10-22
Also published as: CN110669469A

Abstract

The invention relates to a two-component polyurethane structural adhesive and a preparation method and application thereof, wherein the raw material formula of a component A comprises the following components: 5-40% of at least one hydrophobic polyol; 10-50% of at least one polybutadiene polyol; 5-40% of at least one polyether polyol; 0.05-0.5% of a catalyst; 2-10% of a molecular sieve; 10-40% of a filler; the raw material formula of the component B comprises: 40-90% of at least one polyurethane prepolymer; 9-55% of a filler; 1-5% of a water removing agent. Compared with the traditional two-component polyurethane structural adhesive, the adhesive has high initial strength and high elasticity, and has wider adhesive applicability to plastic substrates. Compared with single-component polyurethane hot melt adhesive, the single-component polyurethane hot melt adhesive does not need special equipment investment, and the gluing temperature is low, so that the material cannot be damaged. Compared with the two-component epoxy structural adhesive and the acrylic structural adhesive, the product has higher elongation, small shrinkage after curing and extremely low odor.

Description

Two-component polyurethane structural adhesive and preparation method and application thereof

Technical Field

The invention belongs to the technical field of chemical structure adhesives, and particularly relates to a two-component polyurethane structure adhesive as well as a preparation method and application thereof.

Background

China is the largest automobile producing country in the world at present and accounts for about 30 percent of the total global production. With serious automotive fuel consumption and emissions problems. According to the policy requirements of energy conservation and environmental protection, the light weight of the automobile is one of the most effective ways for saving energy, and is also an important target pursued by international advanced automobile manufacturers. It is estimated that for every 10% weight reduction of a car, 8% -10% of the fuel, CO, is saved₂The emission is reduced by 0.5-0.8 g/km.

The adoption of high-performance lightweight materials is an important approach to achieving lightweight automobiles, and therefore plastic materials are also increasingly used in automobile manufacturing. High-strength glass Fiber Reinforced Plastics (FRPs), such as Sheet Molding Composites (SMCs), resin transfer molding composites (RTMs), and the like, have been widely used in automobiles. More and more subsequent automobile body parts can be plasticized, and external decorative panels including bumper skins, fenders, tail doors, spoilers, doorsills, trunk compartments and the like can be made of thermoplastic plates. At present, plastics and composite materials (SMC, PP/LGF, PE, ABS, PC, PMMA, PVC and the like) are applied to automobile bodies and four doors and two covers, and plastic tail doors are adopted in automobile models such as Nissan New Jun produced in Japan, Changan David Seilon, Jaguar polar light and the like. The application reduces the weight of the automobile, improves the appearance of the automobile and reduces the cost of processing, assembling and maintaining parts. Components such as a cover plate, a busbar bracket, a side plate insulating plate, an end insulating plate and the like in the new energy automobile battery module also adopt plastic materials (PP, PPE, SMC and the like)

The plastic and the composite material are successfully applied to the automobile industry, higher requirements are provided for the bonding of automobile parts, and the traditional processes such as stamping, welding, riveting and the like are replaced by the bonding of the adhesive. Good bonding of automobile plastic exterior trimming parts and good bonding of new energy automobile battery module plastic components are realized, and higher and more comprehensive requirements are provided for the performance of the adhesive. With the development of industrial automation, the production rhythm of a production line is accelerated, and the adhesive is required to have high initial strength and is suitable for high-efficiency mass production. The automobile plastic tail door and the spoiler are made of various materials, and the adhesive is required to have good adhesive property to various different plastic materials. In addition, the adhesive is required to have high elongation after being cured, bear various dynamic loads and static loads in the operation process, and ensure that the automobile body does not crack under external force under different working conditions because different materials deform at different temperatures.

In patent CN 206749482U, a plastic tail gate connecting device for an automobile is disclosed, which uses a two-component polyurethane adhesive to connect an inner plate (PP-LGF30 material) and an outer plate (PP-EPDMT30 material) of the tail gate. Said patent focuses on the connection scheme of the tailgate, and does not describe in detail the preparation method and various properties of the polyurethane adhesive, and the application of the polyurethane adhesive to other plastic materials.

Patent CN 104371632B describes a two-component polyurethane adhesive for bonding fiber reinforced plastics, which can achieve high tearing effect of the substrate on SMC substrate without surface treatment (grinding, priming, plasma, flame, etc.). However, the adhesive has high bonding strength, belongs to structural bonding, has low elasticity, and cannot meet the requirement of elastic bonding (elongation is more than 200%) of automobile exterior trimming parts (tail doors, spoilers and the like).

Patent CN 108676534 a describes an adhesive for bonding plastic parts of automobiles and a preparation method thereof. The adhesive is an epoxy structural adhesive, has good high temperature resistance (100 ℃) and is used for bonding plastic parts at high-temperature parts of automobile engines and the like. However, the patent does not relate to an adhesive for automobile exterior trim materials, and the elongation of the epoxy structural adhesive is generally low, so that the requirement of the adhesive on the elastic bonding elongation of large exterior trims cannot be met.

Patent CN 102516918A introduces a two-component polyurethane adhesive with high elongation and its preparation method. After the adhesive is cured, the elongation can reach 1000%, and the tensile strength is 1.5 MPa. The adhesive disclosed by the patent has low strength, has no advantage in bonding plastic base materials, and is mainly used for common joint filling and sealing of high-deformation parts.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a two-component polyurethane structural adhesive which has high initial strength, good bonding performance on various plastic materials and high elongation after curing, and a preparation method and application thereof.

In order to solve the technical problems, the invention adopts the following technical scheme:

one object of the present invention is to provide a two-component polyurethane structural adhesive comprising an a-component and a B-component,

the formula of the component A comprises the following raw materials by weight percent based on 100 percent of the total mass of the component A:

the formula of the raw material of the component B comprises the following components in percentage by mass of 100 percent of the total mass of the component B:

40-90% of at least one polyurethane prepolymer;

9-55% of a filler;

1-5% of a water removing agent.

According to the invention, through the improvement of the formula and the proportion of the component A and the component B, the product has good bonding performance on various plastic substrates (SMC, PP/LGF, PPE, PE, ABS, PC, PMMA, PVC and the like), is used for bonding automobile tail doors, spoilers and the like, is used for bonding battery cores and module plastic components in new energy automobile batteries, and has high bonding strength. The product has high elasticity after being cured, the elongation is more than 200 percent, and the product can bear larger deformation; the adhesive has high initial strength and can realize high-efficiency large-batch automatic assembly.

Preferably, the raw material formula of the component A comprises the following components in percentage by mass based on 100 percent of the total mass of the component A:

preferably, the raw material formula of the component A also comprises 1-5 wt% of a chain extender, so that the initial strength of the product is further improved.

More preferably, the chain extender is a micromolecular chain extender with a hydroxyl value of 700-1300mgKOH/g, such as one or more of 1, 4-butanediol, diethylene glycol, 3-methyl-1, 5-pentanediol, 2-ethyl-1, 3-hexanediol, trimethylolpropane and the like.

Preferably, the raw material formula of the component A also comprises 0.1-5 wt% of silane coupling agent.

In the present invention, the hydrophobic polyol, the polybutadiene polyol, the polyether polyol, the catalyst, the molecular sieve, the filler, and the silane coupling agent may be those commonly used in the art.

Preferably, the hydrophobic polyol is oil polyol with functionality of 2-4 and hydroxyl value of 170-320mgKOH/g, such as one or more of Sovermol 805, Sovermol 750, Sovermol 815, Sovermol 819, Sovermol 860 and the like.

Preferably, the polybutadiene polyol has a number average molecular weight of 2000-10000g/mol and an average-OH functionality of 2-4. The number average molecular weight of the polybutadiene polyol is preferably in the range of 2000-5000g/mol, and the average-OH functionality is preferably in the range of 2-2.9.

Preferably, the polyether polyol can be polyether polyol obtained by polymerizing ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide, 1, 4-butylene oxide or a mixture thereof as an initiator. The polyether polyol is preferably a polyether polyol having a functionality of two or more and 4000 or less and a number average molecular weight of three or more and more preferably 2000 or less.

Preferably, the catalyst is one or more of dibutyltin dichloride, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dimorpholinyl diethyl ether, bismuth isooctanoate and the like.

Preferably, the molecular sieve is one or more of 3A type, 4A type, 5A type molecular sieve and the like.

Preferably, the filler is one or more of calcium carbonate, kaolin, talcum powder, aluminum hydroxide, white carbon black and the like.

Preferably, the silane coupling agent is one or more of gamma-glycidoxypropylmethyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-aminopropyltrimethoxysilane, aminoethyl methyltrimethoxysilane, anilinopropyltrimethoxysilane and the like.

Preferably, the raw material formula of the component B also comprises 2-10 wt% of isocyanate trimer, so that the adhesive property of the product to the plastic base material is further improved.

Preferably, the raw material formula of the component B also comprises 1-10 wt% of a plasticizer.

In the present invention, the polyurethane prepolymer, the filler, the isocyanate trimer, the water scavenger, and the plasticizer may be prepared from raw materials commonly used in the art.

Preferably, the polyurethane prepolymer is prepared by reacting isocyanate with an isocyanate reactive compound, and the NCO content at the end of the reaction is controlled to be 2-20%, wherein the isocyanate comprises diisocyanate, polyisocyanate and the like, and the isocyanate reactive compound comprises polyester polyol, polyether polyol and the like.

Preferably, the polyurethane prepolymer is prepared by reacting at 70-80 ℃ under the protection of nitrogen.

According to a specific and preferred embodiment of the present invention, the polyurethane prepolymer comprises a first polyurethane prepolymer and a second polyurethane prepolymer in a mass ratio of 4-6: 1, wherein the NCO content of the first polyurethane prepolymer is 15-20%, and the NCO content of the second polyurethane prepolymer is 2-5%.

Further preferably, the first polyurethane prepolymer is prepared by reacting polymeric MDI and polyester polyol, and the second polyurethane prepolymer is prepared by reacting isophorone diisocyanate and polyether diol.

Preferably, the isocyanate trimer is one or more of HDI trimer, TDI trimer, IPDI trimer and the like.

Preferably, the filler is one or more of calcium carbonate, white carbon black, kaolin, talcum powder, aluminum hydroxide and the like.

The water removal agent is one or more of calcium oxide, triethyl orthoformate, p-toluenesulfonyl isocyanate and the like.

The plasticizer is one or more of dioctyl phthalate, diisodecyl phthalate, diisononyl phthalate, dioctyl adipate, phenyl alkyl sulfonate and the like.

When the two-component polyurethane structural adhesive is used, the volume ratio of the component A to the component B is 1: 0.9-1.1, so that the component A and the component B are preferably packaged by double pipes according to the using volume, and therefore the two-component polyurethane structural adhesive is convenient for users to use, does not need to be weighed and mixed when used, and is convenient to use.

The second purpose of the invention is to provide a preparation method of the two-component polyurethane structural adhesive, wherein the preparation method of the component A comprises the following steps: adding the hydrophobic polyol, the polybutadiene polyol and the polyether polyol into a reaction kettle, selectively adding a chain extender, heating to 110-130 ℃, stirring and dehydrating for 1-2 hours under a vacuum condition, cooling to below 50 ℃, then adding the catalyst, the molecular sieve and the filler into the reaction kettle, selectively adding the silane coupling agent, and uniformly stirring under a vacuum condition to obtain the polyurethane foam;

the preparation method of the component B comprises the following steps: adding the polyurethane prepolymer, the filler and the water removal agent into a container, selectively adding the isocyanate trimer and the plasticizer, and uniformly dispersing under a vacuum condition to obtain the polyurethane prepolymer.

The third purpose of the invention is to provide the application of the two-component polyurethane structural adhesive in the bonding of automobile plastic parts and the bonding of plastic components in new energy automobile battery modules.

Due to the implementation of the technical scheme, compared with the prior art, the invention has the following advantages:

compared with the traditional two-component polyurethane structural adhesive, the adhesive has high initial strength and high elasticity, and has wider adhesive applicability to plastic substrates. Compared with single-component polyurethane hot melt adhesive, the single-component polyurethane hot melt adhesive does not need special equipment investment, and the gluing temperature is low, so that the material cannot be damaged. Compared with the two-component epoxy structural adhesive and the acrylic structural adhesive, the product has higher elongation, small shrinkage after curing and extremely low odor.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the present invention is not limited to the following examples. The implementation conditions adopted in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not mentioned are conventional conditions in the industry. The parts referred to in the invention are parts by weight.

(1) The polyhydric alcohol in the component A: a1: polyether triol (molecular weight 1000g/mol, Kunshan Country chemical Co., Ltd.), A2: hydrophobic polyol (trade name Sovermol, functionality of 2.0, average hydroxyl number of about 200-210mgKOH/g), A3: polybutadiene polyols (hydroxyl number from 44 to 56mgKOH/g, Zibozilon chemical Co., Ltd.), A4: small chain extender TMP (hydroxyl value, 1254mgKOH/g, BASF corporation), molecular sieve: type 3A, shanghai new molecular sieves ltd, silane coupling agent: silquest A-187, MOMENTIVE Inc., catalyst: DBTDL T-12, air chemical engineering.

Preparation of the component A: adding four kinds of polyhydric alcohols (A1, A2, A3 and A4) according to the mixture ratio of Table 1 into a reaction kettle, heating to 120 ℃, stirring and dehydrating for 2 hours under vacuum, and cooling to the temperature of less than 50 ℃; and then adding the molecular sieve, the filler, the coupling agent and the catalyst into the reaction kettle, uniformly stirring under a vacuum condition, subpackaging, sealing and storing. The components of component A are shown in Table 1.

TABLE 1

(2) The polyurethane prepolymer and the isocyanate compound in the component B: b1: a polyurethane prepolymer prepared by reacting polymeric MDI (PM-200, Tantanhua polyurethane Co., Ltd.) and polyester polyol (Unipol 620, Mn 2000, Shanghai Yiqing trade Co., Ltd.) at 80 ℃ for 2 hours under the protection of nitrogen, wherein the NCO content at the reaction end point is controlled to be 15-20%; b2: a polyurethane prepolymer, which is prepared by reacting isophorone diisocyanate (IPDI, Covestro company) and polyether diol (DL-4000D, Shandong Lanxingdong Daihong chemical industry Co., Ltd.) at 80 ℃ for 2 hours under the protection of nitrogen, and controlling the NCO content at the reaction end point to be 2-5%; b3: HDI trimer with an average functionality of about 3-4 (Desmoudur N3600, Covestro).

Water removal agent: PTSI, Covestro, plasticizer: JAYFLEX^TMDIDP, Exxonmobil chemical commerce, Inc.

Preparation of the component B: mixing the polyurethane prepolymer and isocyanate compound (HDI trimer) according to the proportion shown in Table 2, adding a water removing agent, a filler, a plasticizer and the like, uniformly dispersing under a vacuum condition, subpackaging, sealing and storing. The ingredients of the curing agent B component are shown in Table 2.

TABLE 2

(2) Tensile strength test: the tensile strength and elongation at break of the dumbbell-shaped splines after curing for 7d in the standard environment were tested according to the standard GB/T528-.

(3) Shear strength test: firstly wiping dust or stains on the surface of a plastic substrate by alcohol, putting a two-component polyurethane sample (1/1 double pipes in volume ratio) into a glue gun, slightly pushing a push rod until the two components are all glued, then installing a mixing pipe to glue at the bonding part of the plastic substrate, clamping and pressing by a clamp, fixing the bonding area (25mm multiplied by 12.5mm) and controlling the thickness of a glue layer to be 1 mm. The sample is prepared in a standard environment of 23 ℃/50% RH, the initial strength test substrate is a common PP/LGF substrate, the initial strength of curing for 5min at 80 ℃ and curing for 1h in the standard environment is respectively tested, the shear strength after curing for 7d in the standard environment is tested according to the standard GB/T7124, and the test result is shown in Table 3.

Destruction form: according to the shear strength test method, whether the pulled plastic sample piece is interface failure (AF) or internal failure (CF) in the adhesive layer of the adhesive layer is observed.

TABLE 3 bonding results of two-component polyurethane adhesives to plastic substrates

Wherein, the shear strength test results in table 3, taking "1.01/AF" as an example, mean that under 1.01MPa, in the multi-group parallel test example, 100% of the damage of the PP-PP plastic sample on the adhesive layer bonding part is interface damage; taking "2.21/85 CF" as an example, the failure of 85% of PP-PP plastic samples in the adhesive part of the adhesive layer is cohesive failure of the adhesive layer in a multi-group parallel test example under 2.21 MPa.

The results of the adhesion experiment of the two-component polyurethane adhesive with different optimized formulations to the plastic substrate are shown in table 3. By comparing A-1/B-1 with A-2/B-2, it can be seen that the adhesive strength to plastic substrates and the elongation of the structural adhesive can be improved by adding polybutadiene polyol and polyurethane prepolymer B2. By comparing A-2/B-2 with A-2/B-3, it can be seen that the adhesion strength of the structural adhesive to the plastic substrate can be improved by the HDI trimer. By comparing A-2/B-3 with A-3/B-3, it can be seen that the tensile strength and initial strength of the structural adhesive can be improved by adding a small molecule chain extender.

In addition, as can be seen from table 3, in the embodiment of the two-component polyurethane adhesive of a-3/B-3 in the present invention, the components are organically combined by optimizing the components of the formula, so that the structural adhesive has high adhesive strength to various plastic substrates (SMC, PP/LGF, PPE, PE, ABS, PC, PMMA, PVC, etc.), and the failure modes are cohesive failure of the adhesive layer, and the various plastic substrates have good adhesive properties in self-adhesion or mutual adhesion. The initial strength of the adhesive is high, and high-efficiency large-batch automatic assembly can be realized; the adhesive has high elasticity after being cured, and the elongation is more than 200 percent. In conclusion, the high-initial-strength and high-elasticity polyurethane adhesive of the embodiment can be used for bonding automobile exterior trimming parts (plastic tail doors, spoilers and the like) and bonding new energy automobile batteries (between battery cores and module plastic components and between module plastic components).

The present invention has been described in detail in order to enable those skilled in the art to understand the invention and to practice it, and it is not intended to limit the scope of the invention, and all equivalent changes and modifications made according to the spirit of the present invention should be covered by the present invention.

Claims

1. A two-component polyurethane structural adhesive is characterized in that: comprises an A component and a B component,

5-10% of at least one hydrophobic polyol;

30-50% of at least one polybutadiene polyol;

5-10% of at least one polyether polyol;

0.05-0.5% of a catalyst;

2-10% of a molecular sieve;

30-40% of a filler;

the raw material formula of the component A also comprises 1-5 wt% of a chain extender;

the hydrophobic polyol is grease polyol with the functionality of 2-4 and the hydroxyl value of 170-320 mgKOH/g;

40-90% of at least one polyurethane prepolymer;

9-55% of a filler;

1-5% of a water removing agent;

the raw material formula of the component B also comprises 2-10 wt% of isocyanate trimer;

the polyurethane prepolymer comprises the following components in a mass ratio of 4-6: 1, wherein the NCO content of the first polyurethane prepolymer is 15-20%, and the NCO content of the second polyurethane prepolymer is 2-5%.

2. The two-part polyurethane structural adhesive of claim 1, wherein: the chain extender is one or more of 1, 4-butanediol, diethylene glycol, 3-methyl-1, 5-pentanediol, 2-ethyl-1, 3-hexanediol, trimethylolpropane and pentaerythritol.

3. The two-part polyurethane structural adhesive of claim 1, wherein: the raw material formula of the component A also comprises 0.1-5 wt% of silane coupling agent.

4. The two-part polyurethane structural adhesive of claim 1, wherein: the raw material formula of the component B also comprises 1-10 wt% of a plasticizer.

5. The two-part polyurethane structural adhesive of claim 1, wherein:

the polybutadiene polyol has a number average molecular weight of 2000-10000g/mol and an average-OH functionality of 2-4; and/or the presence of a gas in the gas,

the polyether polyol is obtained by polymerizing ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide, 1, 4-butylene oxide or a mixture thereof serving as an initiator; and/or the presence of a gas in the gas,

the polyurethane prepolymer is prepared by reacting isocyanate with an isocyanate-reactive compound; the isocyanate-reactive compound comprises a polyester polyol and/or a polyether polyol.

6. A process for preparing the two-component polyurethane construction adhesive according to any one of claims 1 to 5, characterized in that: the preparation method of the component A comprises the following steps: adding the hydrophobic polyol, the polybutadiene polyol and the polyether polyol into a reaction kettle, adding a chain extender, heating to 110-130 ℃, stirring and dehydrating for 1-2h under a vacuum condition, cooling to below 50 ℃, then adding the catalyst, the molecular sieve and the filler into the reaction kettle, optionally adding a silane coupling agent, and uniformly stirring under a vacuum condition to obtain the polyurethane foam material;

the preparation method of the component B comprises the following steps: adding the polyurethane prepolymer, the filler and the water removal agent into a container, adding an isocyanate trimer and a plasticizer, and uniformly dispersing under a vacuum condition to obtain the polyurethane prepolymer.

7. Use of the two-component polyurethane structural adhesive according to any one of claims 1 to 5 for bonding plastic parts of automobiles and plastic components of battery modules of new energy automobiles.

8. Use according to claim 7, characterized in that: the component A and the component B are used according to the volume ratio of 1: 0.9-1.1.