阅读说明：本技术 复合型热熔胶及应用该热熔胶的复合板 (Composite hot melt adhesive and composite board using same ) 是由 徐炀 钱龙 于 2021-10-27 设计创作，主要内容包括：本申请属于热熔胶技术领域,具体涉及一种复合型热熔胶及应用该热熔胶的复合板,包括如下重量份的各组分：聚醚多元醇20-40份、聚酯多元醇60-80份、异氰酸酯40-60份、丙烯酸树脂15-25份、催化剂0.2-1份、改性填料2-6份、扩链剂2-6份。本申请复合型热熔胶为反应型聚氨酯热熔胶,采用较少的聚醚多元醇配合较多的聚酯多元醇,在保证粘结强度的同时有助于提高热熔胶的耐水性,同时,所添加的丙烯酸树脂不仅可以起到增粘作用,还可以起到润湿基材,提高粘接力的作用,而且也有助于改善热熔胶的耐水性。(The application belongs to the technical field of hot melt adhesives, and particularly relates to a composite hot melt adhesive and a composite board using the same, which comprise the following components in parts by weight: 20-40 parts of polyether polyol, 60-80 parts of polyester polyol, 40-60 parts of isocyanate, 15-25 parts of acrylic resin, 0.2-1 part of catalyst, 2-6 parts of modified filler and 2-6 parts of chain extender. The utility model provides a compound hot melt adhesive is reaction type polyurethane hot melt adhesive, adopts less polyether polyol to cooperate more polyester polyol, helps improving the water proofness of hot melt adhesive when guaranteeing bond strength, and simultaneously, the acrylic resin that adds not only can play the tackification effect, can also play moist substrate, improves the effect of adhesion, also helps improving the water proofness of hot melt adhesive moreover.)

1. The utility model provides a compound hot melt adhesive which characterized in that: the paint comprises the following components in parts by weight:

20-40 parts of polyether polyol

60-80 parts of polyester polyol

40-60 parts of isocyanate

15-25 parts of acrylic resin

0.2 to 1 portion of catalyst

5-10 parts of modified filler

And 2-6 parts of a chain extender.

2. The composite hot melt adhesive of claim 1, wherein: the polyether polyol is one or more of polyethylene glycol, polypropylene glycol, poly (1, 2-propylene glycol), poly (1, 3-propylene glycol) and polyethylene glycol-propylene glycol copolymer;

the polyester polyol is one or more of polyethylene glycol adipate glycol, polybutylene glycol adipate glycol, polyhexamethylene glycol adipate glycol and neopentyl glycol adipate.

3. The composite hot melt adhesive of claim 1, wherein: the isocyanate is diphenylmethane diisocyanate.

4. The composite hot melt adhesive of claim 1, wherein: the catalyst is an organic tin catalyst.

5. The composite hot melt adhesive of claim 1, wherein: the modified filler is a silane coupling agent modified filler, and the filler is one or more of titanium dioxide, fumed silica, talcum powder and light calcium carbonate.

6. The composite hot melt adhesive of claim 5, wherein: the silane coupling agent comprises isocyanatopropyl triethoxysilane and KH 570;

the preparation method of the modified filler comprises the following steps: adding 1-3 parts of KH570 and 5-8 parts of isocyanatopropyltriethoxysilane into ethanol to prepare a silane coupling agent solution with the concentration of 20-30%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2000-3000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing to stir for 10-20min after the spraying is finished, and then drying to obtain the modified filler.

7. The composite hot melt adhesive of claim 6, wherein: the silane coupling agent also comprises an anti-aging coupling agent, and the structural formula of the anti-aging coupling agent is as follows:

。

8. the composite hot melt adhesive of claim 7, wherein: the preparation method of the modified filler comprises the following steps: adding 1-3 parts of KH570, 5-8 parts of isocyanatopropyl triethoxysilane and 20-30 parts of an anti-aging coupling agent into ethanol to prepare a silane coupling agent solution with the concentration of 20-30%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 3000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuously stirring for 10-20min after the spraying is finished, and drying to obtain the modified filler.

9. The composite hot melt adhesive of claim 1, wherein: the chain extender is one or more of ethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 2-methyl-1, 3-propanediol and hexanediol.

10. A composite panel to which the composite hot melt adhesive of claim 1 is applied, wherein: the plastic core plate is adhered to the metal plates through hot melt adhesive.

Technical Field

The application belongs to the technical field of hot melt adhesives, and particularly relates to a composite hot melt adhesive and a composite board using the same.

Background

Composite panels are panels formed by compounding multiple layers of material together, which contribute to better performance than single layer panels. The composite board generally comprises a metal composite board, a wood composite board, a color steel composite board, a rock wool composite board and the like, and all the layers are usually bonded by hot melt adhesive.

The hot melt adhesive can become a liquid with fluidity and viscosity when heated and melted to a certain degree, can generate adhesive force on a base material after being cooled and solidified, and is favored due to the advantages of convenient use, no toxicity, environmental protection, convenient storage, high adhesive strength and the like. The polyurethane hot melt adhesive is prepared by taking a thermoplastic polyurethane elastomer as a matrix component and then adding other auxiliary agents, and because the polyurethane hot melt adhesive contains-NCO and can react with a plurality of functional groups containing active hydrogen to form chemical bonding, the polyurethane hot melt adhesive has stronger adhesive force for a plurality of base materials and has wider application range.

Chinese patent document CN 104232005A discloses a high heat-resistant polyurethane hot melt adhesive and a preparation method thereof, wherein polyester polyol and diisocyanate are taken as main materials, and a chain extender and an anti-aging auxiliary agent are matched to prepare the polyurethane hot melt adhesive, and the prepared hot melt adhesive has good heat resistance and high peel strength. While complete use of the polyester polyol helps to achieve better heat resistance and peel strength, the water resistance is poor due to the presence of a large amount of ester groups in the polyester polyol.

For the above reasons, it is necessary to improve the water resistance of polyurethane hot melt adhesive, obtain a hot melt adhesive with better performance in all aspects, and further expand the application range of the hot melt adhesive.

Disclosure of Invention

In order to solve the problems, the application discloses a composite hot melt adhesive and a composite board applying the hot melt adhesive, the hot melt adhesive is a reactive polyurethane hot melt adhesive, less polyether polyol is adopted to match with more polyester polyol, the bonding strength is ensured, the water resistance of the hot melt adhesive is improved, and meanwhile, the added acrylic resin can play a role in tackifying and is also helpful for further improving the water resistance of the hot melt adhesive.

In a first aspect, the present application provides a composite hot melt adhesive, which adopts the following technical scheme:

the composite hot melt adhesive comprises the following components in parts by weight:

20-40 parts of polyether polyol

60-80 parts of polyester polyol

40-60 parts of isocyanate

15-25 parts of acrylic resin

0.2 to 1 portion of catalyst

5-10 parts of modified filler

And 2-6 parts of a chain extender.

Preferably, the polyether polyol is one or more of polyethylene glycol, polypropylene glycol, poly-1, 2-propylene glycol, poly-1, 3-propylene glycol and polyethylene glycol-propylene glycol copolymer;

the polyester polyol is one or more of polyethylene glycol adipate glycol, polybutylene glycol adipate glycol, polyhexamethylene glycol adipate glycol and neopentyl glycol adipate.

Preferably, the isocyanate is diphenylmethane diisocyanate.

Preferably, the catalyst is an organotin catalyst.

Preferably, the modified filler is a silane coupling agent modified filler, and the filler is one or more of titanium dioxide, fumed silica, talcum powder and light calcium carbonate.

Preferably, the silane coupling agent includes isocyanatopropyltriethoxysilane and KH 570;

the preparation method of the modified filler comprises the following steps: adding 1-3 parts of KH570 and 5-8 parts of isocyanatopropyltriethoxysilane into ethanol to prepare a silane coupling agent solution with the concentration of 20-30%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2000-3000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing to stir for 10-20min after the spraying is finished, and then drying to obtain the modified filler.

Preferably, the silane coupling agent further comprises an anti-aging coupling agent, and the structural formula of the anti-aging coupling agent is as follows:

the preparation method of the anti-aging coupling agent comprises the following steps: adding 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) allyl propionate and triethoxysilane in a molar ratio of 1:1 into a reaction kettle, adding 20ppm of a Pt-PMVS catalyst, stirring and heating to 90 ℃, continuing stirring and reacting for 8 hours after the 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) allyl propionate is completely melted to obtain the anti-aging coupling agent, wherein the reaction equation is as follows:

preferably, the preparation method of the modified filler comprises the following steps: adding 1-3 parts of KH570, 5-8 parts of isocyanatopropyl triethoxysilane and 20-30 parts of an anti-aging coupling agent into ethanol to prepare a silane coupling agent solution with the concentration of 20-30%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 3000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuously stirring for 10-20min after the spraying is finished, and drying to obtain the modified filler.

Preferably, the chain extender is one or more of ethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 2-methyl-1, 3-propanediol and hexanediol.

In a second aspect, the present application provides a composite board using a composite hot melt adhesive, which adopts the following technical scheme:

the composite board applying the composite hot melt adhesive comprises a plastic core board in the middle and metal plates on two sides, wherein the plastic core board and the metal plates are bonded through the hot melt adhesive.

The application has the following beneficial effects:

(1) the utility model provides a compound hot melt adhesive is reaction type polyurethane hot melt adhesive, adopts less polyether polyol to cooperate more polyester polyol, helps improving the water proofness of hot melt adhesive when guaranteeing bond strength, and simultaneously, the acrylic resin that adds not only can play the tackification effect, can also play moist substrate, improves the effect of adhesion, also helps improving the water proofness of hot melt adhesive moreover.

(2) The modifier used for modifying the filler in the application is a silane coupling agent which comprises isocyanatopropyl triethoxysilane and KH570, the two silane coupling agents respectively contain double bonds and isocyanato functional groups and can react with different components in a system to form chemical bonds, so that a more comprehensive cross-linked network is formed, the filler is firmly bound and coated in the system, the strength of the system is improved on the premise of not influencing the mechanical performance of the hot melt adhesive, the aging resistance is improved, and the like.

(3) The silane coupling agent used for the modified filler also comprises an anti-aging coupling agent which contains an anti-aging structure, the anti-aging structure is introduced into a system in the form of the silane coupling agent, and the anti-aging structure can be grafted on the surface of the filler, so that the phenomenon that the anti-aging capability is influenced by migration, precipitation and the like of a micromolecule anti-aging agent in the long-term use process is avoided, the service life of the hot melt adhesive is prolonged, and the hot melt adhesive can keep good bonding force for a long time.

Drawings

The present application is further described below with reference to the drawings and examples.

FIG. 1 is a schematic structural view of a composite panel of the present application;

in the figure: 1. a plastic core board; 2. a metal plate.

Detailed Description

The present application will now be described in further detail with reference to examples.

Modified Filler 1

Adding 1 part of KH570 and 8 parts of isocyanatopropyltriethoxysilane into ethanol to prepare a silane coupling agent solution with the concentration of 20%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 20min after the spraying is finished, and then drying to obtain the modified filler 1.

Modified Filler 2

Adding 3 parts of KH570 and 5 parts of isocyanatopropyl triethoxysilane into ethanol to prepare a 30% silane coupling agent solution, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 3000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 10min after spraying is finished, and then drying to obtain the modified filler 2.

Modified Filler 3

Adding 2 parts of KH570 and 7 parts of isocyanatopropyltriethoxysilane into ethanol to prepare a silane coupling agent solution with the concentration of 25%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2500r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 15min after the spraying is finished, and then drying to obtain the modified filler 3.

Modified filler 4

Adding 1 part of KH570, 8 parts of isocyanatopropyl triethoxysilane and 20 parts of anti-aging coupling agent into ethanol to prepare a silane coupling agent solution with the concentration of 20%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 20min after the spraying is finished, and then drying to obtain the modified filler 4.

Modified filler 5

Adding 3 parts of KH570, 5 parts of isocyanatopropyl triethoxysilane and 30 parts of anti-aging coupling agent into ethanol to prepare a 30% silane coupling agent solution, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 3000r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 10min after spraying is finished, and then drying to obtain the modified filler 5.

Modified filler 6

Adding 2 parts of KH570, 7 parts of isocyanatopropyl triethoxysilane and 25 parts of anti-aging coupling agent into ethanol to prepare a silane coupling agent solution with the concentration of 25%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2500r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 15min after the spraying is finished, and then drying to obtain the modified filler 6.

Modified filler 7

Adding 9 parts of KH570 into ethanol to prepare a silane coupling agent solution with the concentration of 25%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2500r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing to stir for 15min after spraying is finished, and then drying to obtain the modified filler 7.

Modified Filler 8

Adding 9 parts of isocyanatopropyltriethoxysilane into ethanol to prepare a 25% silane coupling agent solution, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2500r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 15min after spraying is finished, and then drying to obtain the modified filler 8.

Modified Filler 9

Adding 7 parts of KH570 and 2 parts of isocyanatopropyltriethoxysilane into ethanol to prepare a silane coupling agent solution with the concentration of 25%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2500r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 15min after the spraying is finished, and then drying to obtain the modified filler 9.

Modified filler 10

Adding 2 parts of KH570 and 7 parts of KH550 into ethanol to prepare a silane coupling agent solution with the concentration of 25%, adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2500r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing stirring for 15min after the spraying is finished, and drying to obtain the modified filler 10.

Modified filler 11

Adding 2 parts of KH570, 7 parts of isocyanatopropyl triethoxysilane and 25 parts of antioxidant 1076 into ethanol to prepare a silane coupling agent solution with the concentration of 25% (the antioxidant 1076 cannot be well dissolved in the ethanol and can be uniformly dispersed), adding 100 parts of filler into a dispersion machine, controlling the stirring speed at 2500r/min, spraying the silane coupling agent solution into the filler in a spraying manner while stirring, continuing to stir for 15min after the spraying is finished, and then drying to obtain the modified filler 11.

Example 1

(1) Adding 10 parts of polyethylene glycol, 10 parts of poly (1, 3-propylene glycol), 30 parts of polybutylene adipate glycol, 30 parts of neopentyl glycol adipate, 15 parts of acrylic resin and 5 parts of modified filler 4 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 40 parts of diphenylmethane diisocyanate and 0.2 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1 h;

(3) adding 1 part of propylene glycol and 1 part of 2-methyl-1, 3-propylene glycol, continuing to react for 0.5h, and performing vacuum defoaming to obtain the composite hot melt adhesive.

Example 2

(1) Adding 20 parts of polypropylene glycol, 10 parts of poly (1, 3-propylene glycol), 10 parts of polyethylene glycol-propylene glycol copolymer, 40 parts of polyethylene glycol adipate glycol, 40 parts of polybutylene glycol adipate glycol, 25 parts of acrylic resin and 10 parts of modified filler 5 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 60 parts of diphenylmethane diisocyanate and 1 part of stannous octoate, stirring and heating to 85 ℃, and reacting for 1.5 h;

(3) adding 2 parts of ethylene glycol, 2 parts of 1, 3-butanediol and 3 parts of hexanediol, continuing to react for 1 hour, and defoaming in vacuum to obtain the composite hot melt adhesive.

Example 3

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 6 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Example 4

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 1 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Example 5

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 2 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Example 6

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 3 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Comparative example 1

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 7 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Comparative example 2

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 8 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Comparative example 3

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 9 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Comparative example 4

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 10 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

Comparative example 5

(1) Adding 15 parts of polyethylene glycol, 15 parts of poly (1, 2-propylene glycol), 35 parts of polyethylene glycol adipate glycol, 20 parts of acrylic resin and 8 parts of modified filler 11 into a reaction kettle, uniformly stirring, heating to 120 ℃, opening a vacuum pump, and dehydrating for 2 hours under the condition that the vacuum degree is 0.08 MPa;

(2) cooling to 50 ℃, adding 50 parts of diphenylmethane diisocyanate and 0.6 part of dibutyltin dilaurate, stirring and heating to 85 ℃, and reacting for 1.2 h;

(3) adding 2 parts of ethylene glycol and 2 parts of 1, 4-butanediol, continuing to react for 0.7h, and carrying out vacuum defoaming to obtain the composite hot melt adhesive.

The hot melt adhesives prepared in examples 1 to 6 and comparative examples 1 to 5 were subjected to a performance test, and the initial adhesion strength was the adhesion strength after placing a sample in a constant temperature and humidity chamber (25 ℃, 50% RH) for 15 min; the final adhesion strength is the adhesion strength after the sample was left in a constant temperature and humidity chamber (25 ℃ C., 50% RH) for 7 days. The tensile strength is the result obtained by placing the dumbbell-shaped test sample in a constant temperature and humidity chamber (25 ℃, 50% RH) for 7d and then performing a tensile test by using a tensile testing machine; the tensile strength after aging was obtained by placing a dumbbell-shaped specimen in a constant temperature and humidity chamber (25 ℃ C., 50% RH) for 7 days into an aging resistance test chamber (85 ℃ C., 85% RH) for 1000 hours. The test results are shown in Table 1.

TABLE 1

As can be seen from Table 1, the hot melt adhesives prepared in examples 1 to 6 had initial adhesive strengths of 2.24 to 2.76MPa and final adhesive strengths of 9.16 to 10.18MPa, and had good adhesive properties. The tensile strength is more than 7.9MPa, the strength is high, wherein, the modified fillers of the examples 1 to 3 contain the anti-aging coupling agent, the tensile strength is reduced from 9.7 to 10.8MPa to 8.8 to 9.2MPa after aging, the reduction range is small, and the modified fillers have good anti-aging performance. Examples 4-6 did not test the aging resistance effect without the anti-aging coupling agent, but the modified filler used did not contain the anti-aging coupling agent, which increased the percentage of filler in the hot melt adhesive, and thus decreased both the adhesive strength and the tensile strength. It can be seen from comparative example 1 that, compared to example 6, comparative example 1 uses modified filler 7 and silane coupling agent KH570 as the whole, and although KH570 can react with acrylic acid to increase the crosslinking degree and cohesive energy, since it does not have isocyanate group which can form chemical bond with the surface of the substrate, the adhesive strength is reduced, and since KH570 can only react with acrylic acid, the tensile strength is reduced. As can be seen from comparative example 2, in comparison with example 6, the modified filler used in comparative example 2 was modified filler 8, and the silane coupling agent used was all isocyanatopropyltriethoxysilane, which, although reacting with a polyol to increase the degree of crosslinking and cohesive energy, failed to react with acrylic acid and therefore decreased the tensile strength, and in addition, a larger amount of isocyanato group was advantageous for increasing the adhesive strength. As can be seen from comparative example 3, the modified filler used in comparative example 3 was modified filler 9, and the use of more KH570 and less isocyanatopropyltriethoxysilane reduced the isocyanate content, resulting in a slight decrease in adhesion as compared to example 6. It can be seen from comparative example 4 that, compared with example 6, the modified filler used in comparative example 4 is modified filler 10, and KH550 containing amino group is used to replace isopropyltriethoxysilane isocyanate, because the amino group in KH550 contains two active hydrogens capable of reacting with isocyanate group, the viscosity of the hot melt adhesive is increased, although KH550 containing amino group is easy to form chemical bond with the surface of the substrate to improve the initial adhesion effect, the viscosity is relatively high, the fluidity is relatively poor, the final adhesion strength is lower than that of example 6, but the tensile strength is slightly higher. As can be seen from comparative example 5, in comparison with example 3, comparative example 5 uses modified filler 11, the antioxidant 1076 with the same mass is used in the preparation process of modified filler 11 to replace the anti-aging silane coupling agent, and the tensile strength of comparative example 5 after aging is reduced from 9.2MPa to 7.3MPa, which is serious, probably because the antioxidant 1076 can not form effective bonding with the filler and the polyurethane system, so that the antioxidant is easy to migrate and precipitate during aging, thereby reducing the aging resistance.

In a specific embodiment, the addition amount of the anti-aging coupling agent can be adjusted as required to obtain the desired anti-aging effect. Or can be matched with some micromolecule antioxidants for use to make up the condition that the aging resistant effect is reduced because the micromolecule antioxidants are separated out and migrated after a period of time.

As shown in fig. 1, the composite plate using the composite hot melt adhesive prepared by the present application comprises a plastic core plate 1 in the middle and metal plates 2 at two sides, wherein the plastic core plate 1 and the metal plates 2 are bonded by the hot melt adhesive to obtain the composite plate.

The present embodiment is merely illustrative and not restrictive, and various changes and modifications may be made by persons skilled in the art without departing from the scope of the present invention as defined in the appended claims. The technical scope of the present application is not limited to the contents of the specification, and must be determined according to the scope of the claims.