阅读说明：本技术 一种铝合金制品用胶粘剂及其制备方法 (Adhesive for aluminum alloy products and preparation method thereof ) 是由 高嵩 于 2020-08-20 设计创作，主要内容包括：本发明公开了一种铝合金制品用胶粘剂及其制备方法,原料组成包括异氰酸酯50-100重量份、聚醚多元醇50-100重量份、催化剂1.3-1.9重量份、交联剂0.5-1重量份、增粘剂0.5-1重量份；所述异氰酸酯为液化二苯甲烷二异氰酸酯与官能度大于2的多异氰酸酯的混合物,所述聚醚多元醇为改性聚醚。本发明通过对聚醚多元醇进行改性,使该铝合金制品用胶粘剂拥有良好的粘结强度、耐温性能,同时减少了固化时间。(The invention discloses an adhesive for aluminum alloy products and a preparation method thereof, wherein the raw materials comprise 50-100 parts by weight of isocyanate, 50-100 parts by weight of polyether polyol, 1.3-1.9 parts by weight of catalyst, 0.5-1 part by weight of cross-linking agent and 0.5-1 part by weight of tackifier; the isocyanate is a mixture of liquefied diphenylmethane diisocyanate and polyisocyanate with functionality greater than 2, and the polyether polyol is modified polyether. According to the invention, the polyether polyol is modified, so that the adhesive for the aluminum alloy product has good bonding strength and temperature resistance, and the curing time is reduced.)

1. The adhesive for the aluminum alloy product is characterized by comprising 50-100 parts by weight of isocyanate, 50-100 parts by weight of polyether polyol, 1.3-1.9 parts by weight of catalyst, 0.5-1 part by weight of cross-linking agent and 0.5-1 part by weight of tackifier.

2. The adhesive for aluminum alloy products as recited in claim 1, wherein the isocyanate is a mixture of liquefied diphenylmethane diisocyanate and polyisocyanate having a functionality of greater than 2.

3. The adhesive for aluminum alloy products as claimed in claim 2, wherein the weight ratio of the liquefied diphenylmethane diisocyanate to the polyisocyanate having a functionality greater than 2 is 20-50: 80-50.

4. The adhesive for aluminum alloy products as recited in claim 2 or 3, wherein the polyisocyanate having a functionality of greater than 2 is polymethylene polyphenyl polyisocyanate.

5. The adhesive for aluminum alloy products as recited in claim 1, wherein the polyether polyol is an organic compound modified polypropylene containing both ester groups and double bonds.

6. The adhesive for aluminum alloy products as claimed in claim 5, wherein the organic compound containing both ester group and double bond is vinyl acetate.

7. The adhesive for aluminum alloy products as claimed in claim 5, wherein said polypropylene glycol is polypropylene glycol.

8. The adhesive for aluminum alloy products as recited in claim 7, wherein the polypropylene glycol has a number average molecular weight of 800-2000.

9. A method for preparing an adhesive for aluminum alloy products according to any one of claims 1 to 8, comprising the steps of:

s1, adding polypropylene and alkali metal hydroxide into a reaction bottle, wherein the mass ratio of the polypropylene to the alkali metal hydroxide is (1-1.2): 0.6-0.8, adding 0.02-0.05mg/L cobalt naphthenate, heating to 80-120 ℃, and reacting for 1-2 hours to obtain viscous liquid;

s2, adding the viscous liquid and 0.5-1.2ml of initiator into a device with stirring and refluxing, introducing inert gas, stirring and heating to 90-110 ℃, dropwise adding an organic compound containing ester groups and double bonds at a certain speed, after dropwise adding, preserving heat at the temperature of 100-120 ℃ for 1-2h, and removing residual monomers by reduced pressure distillation to obtain modified polypropylene;

and S3, adding the isocyanate, the modified polypropylene, the catalyst, the cross-linking agent and the tackifier into a reaction kettle in sequence by weight, stirring, and reacting for 3-4 hours to obtain the adhesive for the aluminum alloy product.

10. The method of claim 9, wherein the constant speed is 2 to 3 drops/S in step S2.

Technical Field

The invention relates to the technical field of polyurethane adhesives, in particular to an adhesive for aluminum alloy products and a preparation method thereof.

Background

Along with the improvement of production and living standards, the adhesive with a common molecular structure can not meet the application of people in production and living, and the polyurethane adhesive is a polymer adhesive which is developed most rapidly at present and is widely applied in many aspects due to excellent performance. Polyurethane adhesives refer to adhesives containing urethane groups (-NHCOO-) or isocyanate groups (-NCO) in the molecular chain, and can be divided into two major classes, namely polyisocyanates and polyurethanes. Has excellent chemical adhesion with base material containing active hydrogen, such as light metal aluminum alloy, plastic and other material with smooth surface.

However, the existing polyurethane adhesive has the defects of low curing speed, insufficient bonding strength, poor high-temperature resistance, weak toughness caused by insufficient tensile strength of the cured colloid, and the like, and is only suitable for low-temperature environments.

Disclosure of Invention

In order to solve the problems, the first aspect of the invention provides an adhesive for aluminum alloy products, which comprises 50-100 parts by weight of isocyanate, 50-100 parts by weight of polyether polyol, 1.3-1.9 parts by weight of catalyst, 0.5-1 part by weight of cross-linking agent and 0.5-1 part by weight of tackifier.

As a preferred solution, the isocyanate is a mixture of liquefied diphenylmethane diisocyanate (liquefied MDI) and a polyisocyanate having a functionality greater than 2.

As a preferable technical scheme, the weight ratio of the liquefied diphenylmethane diisocyanate to the polyisocyanate with the functionality of more than 2 is 20-50: 80-50.

As a preferred embodiment, the polyisocyanate having a functionality greater than 2 is polymethylene polyphenyl polyisocyanate (PAPI).

As a preferable technical scheme, the polyether polyol is organic compound modified polypropylene containing ester groups and double bonds.

As a preferable technical scheme, the organic compound containing both an ester group and a double bond is vinyl acetate.

As a preferred technical solution, the polypropylene glycol is the polypropylene glycol.

As a preferred technical scheme, the number average molecular weight of the polypropylene glycol is 800-2000.

As a preferable technical scheme, the catalyst is one or a mixture of more of dimorpholinodiethylether, bis (2, 6-dimethylmorpholinoethyl) ether and 1, 2, 4-trimethylpiperazine.

As a preferred technical scheme, the cross-linking agent is triethanolamine.

As a preferable technical scheme, the tackifier is one or a mixture of two of vinyltrimethoxysilane and vinyltriethoxysilane.

The second aspect of the invention provides a preparation method of the adhesive for the aluminum alloy product, which comprises the following steps:

s1, adding polypropylene and alkali metal hydroxide into a reaction bottle, wherein the mass ratio of the polypropylene to the alkali metal hydroxide is (1-1.2): 0.6-0.8, adding 0.02-0.05mg/L cobalt naphthenate, heating to 80-120 ℃, and reacting for 1-2 hours to obtain viscous liquid;

s2, adding the viscous liquid and 0.5-1.2ml of initiator into a device with stirring and refluxing, introducing inert gas, stirring and heating to 90-110 ℃, dropwise adding an organic compound containing ester groups and double bonds at a certain speed, after dropwise adding, preserving heat at the temperature of 100-120 ℃ for 1-2h, and removing residual monomers by reduced pressure distillation to obtain modified polypropylene;

and S3, adding the isocyanate, the modified polypropylene, the catalyst, the cross-linking agent and the tackifier into a reaction kettle in sequence by weight, stirring, and reacting for 3-4 hours to obtain the adhesive for the aluminum alloy product.

Has the advantages that:

1. by selecting a mixture of liquefied MDI and a polyisocyanate having a functionality greater than 2, the cure speed can be increased and the cure time reduced.

2. By selecting the vinyl acetate modified polyether, the temperature resistance and tensile strength of the adhesive are improved.

3. The polyether is modified by selecting the vinyl acetate, so that the dimerization of isocyanate is prevented, and the viscosity of the adhesive is improved.

4. The number average molecular weight of the selected polypropylene is 800-2000, so that the generation of gel is prevented.

5. The polyisocyanate and the modified polyether are polymerized, and micropores of the obtained adhesive are uniformly distributed after curing, so that the adhesive has high tensile strength and is not easy to crack at high temperature.

6. The adhesive prepared by the invention is suitable for various aluminum alloy materials.

Detailed Description

The disclosure may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

In order to solve the problems, the invention provides an adhesive for aluminum alloy products in a first aspect, which comprises 50-100 parts by weight of isocyanate, 50-100 parts by weight of polyether polyol, 1.3-1.9 parts by weight of catalyst, 0.5-1 part by weight of cross-linking agent and 0.5-1 part by weight of tackifier.

Isocyanates are a generic term for the various esters of isocyanic acid. When classified by the number of-NCO groups, these include monoisocyanates and diisocyanates and polyisocyanates, among others. Among them, polyisocyanate is one of the main raw materials for preparing polyurethane adhesives, and the most commonly used are Toluene Diisocyanate (TDI), liquefied diphenylmethane diisocyanate (liquefied MDI), polymethylene polyphenyl polyisocyanate (PAPI), and the like. Toluene Diisocyanate (TDI) has 2, 4-TDI and 2, 6-TDI, which are isomers of each other. TDI has high activity, but high volatility and toxicity. Pure liquefied diphenylmethane diisocyanate (liquefied MDI) is less reactive than Toluene Diisocyanate (TDI).

In order to increase the curing speed of the adhesive, in some preferred embodiments, the isocyanate is a mixture of liquefied MDI and a polyisocyanate having a functionality greater than 2. By selecting a mixture of liquefied MDI and a polyisocyanate having a functionality greater than 2, the presence of low reactive 2, 4-MDI isomers in the liquefied MDI is reduced and the high reactive molecules increase the cure speed and reduce the cure time.

In order to reduce the brittleness of low molecular weight isocyanates, in some preferred embodiments, the weight ratio of the liquefied MDI to the polyisocyanate having a functionality greater than 2 is 20 to 50: 80-50, and the toughness of the cured adhesive is ensured.

The CAS number of the liquefied diphenylmethane diisocyanate of the present invention is 101-68-8;

in some preferred embodiments, the polyisocyanate having a functionality greater than 2 is a polymethylene polyphenyl polyisocyanate;

the polymethylene polyphenyl polyisocyanate in the present invention may be commercially available, for example, UC-52 series products produced by Zhengzhou Keyun chemical engineering Co., Ltd, and UC-52-03 is preferable.

In order to improve the temperature resistance and tensile strength, in some preferred schemes, the polyether polyol is organic compound modified polypropylene containing ester groups and double bonds, on one hand, the double bonds can absorb or bond solid particles suspended in a polyether system by utilizing the special affinity of the double bonds to polymers dispersed in the polyether polyol; meanwhile, the polyether chain extender can form a lyophilic polyether chain with the base polyether, and continuously form a phase around the polyether to form a protective barrier for preventing polymer particles from being adhered, aggregated and settled, so that the temperature resistance and the tensile strength of the system are improved. On the other hand, the carboxyl groups remaining in the system neutralize the basic catalyst remaining during polymerization, thereby preventing dimerization of isocyanate and increasing the viscosity of the adhesive.

In some preferred embodiments, the organic compound containing both an ester group and a double bond is vinyl acetate (CAS number: 108-05-4).

In some preferred embodiments, the polypropylene glycol is polypropylene glycol (CAS number 25322-69-4), the molecular weights are number average molecular weights, and the number average molecular weight is 800-.

The second aspect of the invention provides a preparation method of the adhesive for the aluminum alloy product, which comprises the following steps:

s1, adding polypropylene and alkali metal hydroxide into a reaction bottle, wherein the mass ratio of the polypropylene to the alkali metal hydroxide is (1-1.2): 0.6-0.8, adding 0.02-0.05mg/L cobalt naphthenate, heating to 80-120 ℃, and reacting for 1-2 hours to obtain viscous liquid;

s2, adding the viscous liquid and 0.5-1.2ml of initiator into a device with stirring and refluxing, introducing inert gas, stirring and heating to 90-110 ℃, dropwise adding an organic compound containing ester groups and double bonds at a certain speed, after dropwise adding, preserving heat at the temperature of 100-120 ℃ for 1-2h, and removing residual monomers by reduced pressure distillation to obtain modified polypropylene;

and S3, adding the isocyanate, the modified polypropylene, the catalyst, the cross-linking agent and the tackifier into a reaction kettle in sequence by weight, stirring, and reacting for 3-4 hours to obtain the adhesive for the aluminum alloy product.

In order to increase the grafting rate, in some preferred embodiments, in step S2, the certain speed is 2 to 3 drops/S. When the dripping speed of the vinyl acetate is too high, the dispersity of the liquid is reduced, and the agglomeration phenomenon is caused; when the dropping speed is too slow, the grafting rate of vinyl acetate is reduced, and the performance of the adhesive is affected.

In the present invention, the alkali metal hydroxide is KOH (CAS number: 1310-58-3);

in the invention, the initiator is azobisisobutyronitrile (CAS number: 78-67-1);

in some preferred embodiments, the catalyst is preferably dimorpholinodiethylether (CAS number: 6425-39-4);

in the invention, the cross-linking agent is triethanolamine (CAS number: 102-71-6);

in some preferred embodiments, the adhesion promoter is vinyltrimethoxysilane (CAS number: 2768-02-7) or vinyltriethoxysilane (CAS number: 78-08-0).