CN112795350B

CN112795350B - Oil-acid-resistant reactive polyurethane hot melt adhesive

Info

Publication number: CN112795350B
Application number: CN202011609931.3A
Authority: CN
Inventors: 庄恒冬; 王建斌; 陈田安
Original assignee: Yantai Darbond Technology Co Ltd
Current assignee: Yantai Darbond Technology Co Ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2023-02-03
Anticipated expiration: 2040-12-30
Also published as: CN112795350A

Abstract

The invention discloses an oil acid resistant reaction type polyurethane hot melt adhesive which is a single-component adhesive with 100% solid content, and the formula of the single-component adhesive comprises polyalcohol, p-phenylene diisocyanate, a chain extender, an antioxidant, a coupling agent and a catalyst. The polyol comprises polycarbonate diol, polyester diol and polyether diol. The polyol in the oil acid reaction resistant polyurethane hot melt adhesive adopts the structures of polycarbonate diol, polyester diol, polyether diol and special polyol with special short chain structures, so that the polarity and crosslinking density of a system are improved, the adhesion to a base material is improved, and the corrosion to oleic acid can be coped with; the structure of the chain extender enhances the strength of the system, and improves the crosslinking density of the system and the adhesion to a base material; the p-phenylene diisocyanate has simple structure, strong polarity and high reaction activity, and further improves the model and crosslinking density of the system.

Description

Oil-acid-resistant reactive polyurethane hot melt adhesive

Technical Field

The invention belongs to the technical field of adhesives, and particularly relates to an oil-acid-resistant reactive polyurethane hot melt adhesive.

Background

The reactive polyurethane hot melt adhesive is a single-component and 100% solid-containing environment-friendly adhesive and has hot-melt property and reactivity.

Because the reactive adhesive has the characteristics of simple and convenient gluing, quick curing and high initial viscosity, and has the advantages of high bonding strength, good heat resistance and chemicals resistance and the like of the reactive adhesive, compared with the traditional hot melt adhesive, the reactive adhesive has low use temperature and shows excellent bonding performance on substrates such as wood, ceramics, fabrics, stone, metal, plastics, glass, rubber, leather and the like, the PUR reactive polyurethane hot melt adhesive is widely applied to various industries, such as the automobile industry, the textile and clothing industry, the building industry, the electronic and electrical industry, the book manufacturing industry and the like, and is developed quickly, thereby becoming one of the adhesives developed quickly in China.

In recent years, a great deal of research and development experimental work is performed on the aspects of improving the initial adhesion of the PUR, adjusting the positioning time, improving the bonding strength, improving the flexibility and the heat resistance, and a great number of new technologies and new applications also appear.

With the development of intelligent electronic devices, PUR hot melt adhesives are applied to electronic products more and more, and the requirements on the electronic products are higher and higher. Many electronic products are developed towards integration and screw removal, the traditional glue can not meet the development requirements of modern intelligent equipment, and the PUR hot melt adhesive needs to conform to the development requirements of electronic intelligent equipment and develops the PUR electronic hot melt adhesive meeting the requirements.

Reactive polyurethane hot melt adhesives have become the first choice for industry bonding, sealing, laminating, joining, insulating, electronic protection, and assembly. The specific application comprises the following steps: the frame of cell-phone (cell-phone shell, cell phone stand, cell-phone backshell, cell-phone frame etc.), computer (computer frame, computer keyboard, computer display screen) smart machine bonds earphone, electrical apparatus, navigator, PS machine, public transit POS machine, intelligent fingerprint lock, punched-card machine, connector, automotive electronics, lithium cell, learning machine, GPS navigator, wearable electronic equipment, window bonding, shell structure bonding, plane seal, PCB equipment and protection etc..

The continuous increase of the output of electronic products brings good development opportunities for electronic adhesive enterprises, the market demand has a continuously increasing space, and meanwhile, the widening of the application also puts more requirements on PUR.

Electronic products such as mobile phones, earphones, computer keyboards and chargers can be in contact with a human body for a long time, the human body can generate sweat, sebum, oleic acid and other substances, and particularly in summer, the bonded part is poor in corrosion of sweat, sebum, oleic acid and the like, so that the bonding strength is reduced, even glue is broken, and bonding failure is caused. The main reason for the glue failure is found to be the existence of oleic acid, so that the development of an oleic acid-resistant PUR product is required according to the market demand.

At present, the PUR used in electronics in the market is usually polyol, including polyester polyol, polycarbonate polyol, polyether polyol, acrylic ester polyol and the like, and the mixture of the above polyols, especially the polyester polyol and the polyether polyol, is added with a chain extender, and the diphenylmethane 4,4' -diisocyanate (MDI) is used as a main raw material to synthesize an NCO-terminated prepolymer under appropriate process conditions, and added with tackifying resin, a coupling agent, a catalyst and other components. According to different requirements, the content of the hard segment and soft segment links is properly adjusted to meet different client requirements, the requirements of oleic acid resistance are specially met, and no perfect product exists in the market.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the oil acid resistant reaction type polyurethane hot melt adhesive which has excellent oil acid resistant performance.

The specific technical scheme is as follows:

the formula of the oil acid resistant reaction type polyurethane hot melt adhesive comprises polyhydric alcohol, p-phenylene diisocyanate, a chain extender, an antioxidant, a coupling agent and a catalyst. It is a 100% solids one-component glue.

Further, the polyol includes polycarbonate diol, polyester diol and polyether diol.

According to the invention, through the selection of the special polyol, the polarity and the crosslinking density of the system are improved, the adhesion to a base material is improved, and the corrosion of oleic acid can be responded. The p-phenylene diisocyanate serving as isocyanate with a simple structure provides enough reaction activity, and the short-chain straight-chain structure improves the curing compactness of the product and improves the oil acid resistance of the product.

Further, the formula of the oil acid reaction resistant polyurethane hot melt adhesive comprises the following components in parts by weight: 25-35 parts of polycarbonate dihydric alcohol, 30-50 parts of polyester dihydric alcohol, 10-20 parts of polyether dihydric alcohol, 30-40 parts of p-phenylene diisocyanate, 1-2 parts of chain extender, 0.2-0.6 part of antioxidant, 0.2-1 part of coupling agent, 0.02-0.04 part of organic bismuth catalyst and 0.1-0.5 part of organic amine catalyst.

Still further, the polycarbonate diol is polycarbonate cyclohexyldimethanol-1,6 hexanediol glycol or polycarbonate cyclohexyldimethanol-1,4 butanediol glycol. The molecular weight of the polycarbonate diol is preferably 400 to 1000. The polycarbonate diol with the structure has strong polarity, excellent adhesion, low molecular weight and high crosslinking density, so the oil and acid resistance is excellent.

Still further, the polyester diol is poly adipic acid-1,4 cyclohexyl dimethanol ester diol or poly adipic acid-ethylene glycol ester diol. The molecular weight of the polyester diol is preferably 3000. The polyester diol has strong polarity, low molecular weight and high crosslinking density, improves the chemical and corrosion resistance, and particularly resists the corrosion of oleic acid.

Still further, the polyether glycol is polypropylene glycol PPG-400, and the molecular weight of the polyether glycol is 400. The existence of polyether reduces the viscosity of the system, and can improve the miscibility of each component and the compatibility.

Further, the chain extender is 1,4 cyclohexyl diol or hydrogenated bisphenol A. The existence of the chain extender improves the strength of the product after curing, and the existence of the alicyclic ring improves the bonding strength and the corrosion resistance of the product.

Furthermore, the coupling agent is gamma-mercaptopropyltrimethoxysilane or N- (N-butyl) -3-aminopropyltrimethoxysilane. The coupling agent can react with isocyanate group to generate a blocked polymer, thereby avoiding the existence of free and low-boiling-point substances, and more importantly, improving the bonding capacity to the interface of the substrate

Further, the catalyst is a composite of an organic amine catalyst and an organic bismuth catalyst. The organic amine catalyst is preferably common dimorpholinodiethyl ether, and the organic bismuth catalyst is preferably bismuth neodecanoate with the bismuth content of 20%.

Further, the preparation method of the oil acid reaction resistant polyurethane hot melt adhesive comprises the following steps:

(1) Adding polyol, a chain extender and an antioxidant into a reaction vessel, heating and stirring uniformly, and removing water for 120min in vacuum at 120 ℃; then cooling to 80 ℃ under the protection of nitrogen;

(2) Adding p-phenylene diisocyanate into the reaction container under the protection of nitrogen, and reacting for 15min under the protection of nitrogen at 100 ℃;

(3) Adding an organic bismuth catalyst into the reaction container, and continuously reacting for 45min at 100 ℃ under the protection of nitrogen; adding a coupling agent and an organic amine catalyst, continuing to react for 45min at 100 ℃ under the protection of nitrogen, and then filtering and discharging.

The invention has the following beneficial effects:

the polyol in the oil acid reaction resistant polyurethane hot melt adhesive adopts the structures of polycarbonate diol, polyester diol and polyether diol with special short chain structures, improves the system polarity and crosslinking density, improves the adhesion to a base material, and can cope with the corrosion of oleic acid; the structure of the chain extender enhances the strength of the system, and improves the crosslinking density of the system and the adhesion to a base material; the p-phenylene diisocyanate has simple structure, strong polarity and high reaction activity, and further improves the model and crosslinking density of the system; the existence of the coupling agent improves the bonding effect of the system to the base material; the antioxidant improves the anti-aging reliability of the product; besides controlling the speed of polymerization reaction, the catalyst can make the reaction completely proceed and raise the acid resistance.

Detailed Description

The principles and features of this invention are described below in conjunction with examples, which are included to illustrate the invention and not to limit the scope of the invention.

The "parts" referred to in the detailed description are parts by weight.

Example 1

The preparation method of the oil acid reaction resistant polyurethane hot melt adhesive comprises the following steps:

(1) Adding 25 parts of polycarbonate cyclohexyl dimethanol-1,6 hexanediol diol with the molecular weight of 400, 30 parts of poly adipic acid-ethylene glycol ester diol with the molecular weight of 3000, 10 parts of PPG-400 polypropylene glycol with the molecular weight of 400, 1 part of chain extender 1,4 cyclohexyl diol and 0.6 part of 1010 antioxidant into a reaction container, heating and uniformly stirring, and removing water for 120min in vacuum at the temperature of 120 ℃; then cooling to 80 ℃ under the protection of nitrogen;

(2) Adding 35.55 parts of p-phenylene diisocyanate into a reaction container under the protection of nitrogen, and reacting for 15min under the protection of nitrogen at 100 ℃;

(3) Adding 0.04 part of bismuth neodecanoate serving as a catalyst into the reaction container, and continuously reacting for 45min at 100 ℃ under the protection of nitrogen; adding 1 part of coupling agent gamma-mercaptopropyltrimethoxysilane and 0.1 part of organic amine catalyst dimorpholinodiethylether, reacting for 45min at 100 ℃ under the protection of nitrogen, and then filtering and discharging.

Example 2

(1) Adding 35 parts of 1000 molecular weight polycarbonate cyclohexyl dimethanol-1,6 hexanediol glycol, 50 parts of 3000 molecular weight poly adipic acid-ethylene glycol dihydric alcohol, 20 parts of 400 molecular weight PPG-400 polypropylene glycol, 2 parts of chain extender 1,4 cyclohexyl glycol and 0.2 part of 1010 antioxidant into a reaction container, heating and stirring uniformly, and removing water for 120min in vacuum at 120 ℃; then cooling to 80 ℃ under the protection of nitrogen;

(2) Adding 34.8 parts of p-phenylene diisocyanate into a reaction container under the protection of nitrogen, and reacting for 15min under the protection of nitrogen at 100 ℃;

(3) Adding 0.02 part of catalyst bismuth neodecanoate into the reaction vessel, and continuing to react for 45min at 100 ℃ under the protection of nitrogen; adding 0.2 part of coupling agent gamma-mercaptopropyltrimethoxysilane and 0.5 part of organic amine catalyst dimorpholinodiethylether, reacting for 45min at 100 ℃ under the protection of nitrogen, and then filtering and discharging.

Example 3

(1) Adding 30 parts of polycarbonate cyclohexyl dimethanol-1,6 hexanediol diol with the molecular weight of 800, 40 parts of poly adipic acid-ethylene glycol ester diol with the molecular weight of 3000, 15 parts of PPG-400 polypropylene glycol with the molecular weight of 400, 1.5 parts of chain extender 1,4 cyclohexyl diol and 0.4 part of 1010 antioxidant into a reaction container, heating and stirring uniformly, and removing water for 120min in vacuum at the temperature of 120 ℃; then cooling to 80 ℃ under the protection of nitrogen;

(2) Adding 31.6 parts of p-phenylene diisocyanate into a reaction container under the protection of nitrogen, and reacting for 15min under the protection of nitrogen at 100 ℃;

(3) Adding 0.03 part of catalyst bismuth neodecanoate into the reaction container, and continuing to react for 45min at 100 ℃ under the protection of nitrogen; adding 0.6 part of coupling agent gamma-mercaptopropyltrimethoxysilane and 0.3 part of organic amine catalyst dimorpholinodiethylether, reacting for 45min at 100 ℃ under the protection of nitrogen, and then filtering and discharging.

Example 4

(1) Adding 30 parts of polycarbonate cyclohexyl dimethanol-1,4 butanediol ester diol with the molecular weight of 800, 40 parts of poly adipic acid-1,4 cyclohexyl dimethanol ester diol with the molecular weight of 3000, 15 parts of PPG-400 polypropylene glycol with the molecular weight of 400, 1.5 parts of chain extender hydrogenated bisphenol A and 0.4 part of 1010 antioxidant into a reaction container, heating and stirring uniformly, and removing water for 120min in vacuum at the temperature of 120 ℃; then cooling to 80 ℃ under the protection of nitrogen;

(2) Adding 30.26 parts of p-phenylene diisocyanate into a reaction container under the protection of nitrogen, and reacting for 15min under the protection of nitrogen at 100 ℃;

(3) Adding 0.03 part of catalyst bismuth neodecanoate into the reaction container, and continuing to react for 45min at 100 ℃ under the protection of nitrogen; adding 0.6 part of coupling agent N- (N-butyl) -3-aminopropyltrimethoxysilane and 0.3 part of organic amine catalyst dimorpholinodiethylether, reacting for 45min at 100 ℃ under the protection of nitrogen, filtering and discharging.

Comparative example 1

The reactive polyurethane hot melt adhesive is prepared according to the following steps:

(1) Adding 30 parts of polycarbonate cyclohexyl dimethanol-1,6 hexanediol glycol with the molecular weight of 800, 40 parts of poly adipic acid-ethylene glycol diol with the molecular weight of 3000, 15 parts of PPG-400 polypropylene glycol with the molecular weight of 400, 1.5 parts of chain extender 1,4 cyclohexyl diol and 0.4 part of 1010 antioxidant into a reaction container, heating and stirring uniformly, and removing water for 120min in vacuum at 120 ℃; then cooling to 80 ℃ under the protection of nitrogen;

(2) Adding 49.37 parts of diphenylmethane diisocyanate into the reaction vessel under the protection of nitrogen, and reacting for 15min under the protection of nitrogen at 100 ℃;

Comparative example 1 differs from example 3 in that 30.26 parts of p-phenylene diisocyanate were replaced with 49.37 parts of diphenylmethane diisocyanate; the remaining technical features are the same as those of example 3.

Comparative example 2

(1) Adding 30 parts of 800 molecular weight poly adipic acid-hexanediol ester dihydric alcohol, 40 parts of 3000 molecular weight poly adipic acid-ethylene glycol ester dihydric alcohol, 15 parts of 400 molecular weight PPG-400 polypropylene glycol, 1.5 parts of chain extender 1,4 cyclohexyl glycol and 0.4 part of 1010 antioxidant into a reaction container, heating and stirring uniformly, and removing water for 120min in vacuum at 120 ℃; then cooling to 80 ℃ under the protection of nitrogen;

Comparative example 2 differs from example 3 in that the 800 molecular weight polycarbonate cyclohexyldimethanol-1,6 hexanediol glycol was replaced with an equal amount of 800 molecular weight poly adipic acid-hexanediol glycol; the remaining technical features are the same as those of example 3.

Experiment of

The articles obtained in examples 1 to 4 and comparative examples 1 and 2 were heated to 110 ℃ for experimental tests.

Testing one: pouring the mixture onto a release film with a release agent, rolling the mixture by using a press, controlling the thickness of an adhesive film to be 0.2mm, then placing the adhesive film for 168 hours under the humidity condition of 25 ℃ and 50%, cutting the test piece by making a dumbbell-shaped test piece according to the requirement of GB/T528-2009, then soaking the test piece in oleic acid, and taking out the test piece after 72 hours for comparison test;

and (2) testing: heating the examples 1, 2, 3 and 4 and the comparative examples 1 and 2 to 110 ℃, dispensing to prepare the shear strength of PC to PC, curing the bonding sample according to the requirement of GB/T7124-2008 at 25 ℃ under the condition of 50% humidity for 168h, soaking in oleic acid, and carrying out a shear test after 72 h.

The results are shown in Table 1.

Table 1 comparative table of performance test

Performance index ﹨ sample	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2
							Tensile strength	15.2	15.8	15.0	15.4	14.7	14.8
Tensile strength after oleic acid immersion	8.6	8.2	8.5	8.2	2.5	2.3
							Shear strength	14.5	14.9	14.6	14.1	13.10	14.5
Shear strength after oleic acid immersion	5.2	5.5	5.4	5.5	2.5	1.3

As can be seen from the test comparison data of examples 1-4 and comparative example-1 in Table 1, the p-phenylene diisocyanate used in examples 1-4 has significantly improved resistance to oleic acid, both in tensile strength and in adhesive shear strength, compared to the diphenylmethane diisocyanate used in comparative example 1; as can be seen from the test comparison data of examples 1-4 and comparative-2, the polycarbonate cyclohexanedimethanol-1,6 hexanediol diol or polycarbonate cyclohexanedimethanol-1,4 butanediol diol used in examples 1-4 has significantly improved resistance to oil acids compared to the polyadipic acid hexanediol diol used in comparative example 2, regardless of tensile strength or adhesive shear strength.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The oil acid reaction resistant polyurethane hot melt adhesive is characterized by comprising the following components in parts by weight: 25-35 parts of polycarbonate diol, 30-50 parts of polyester diol, 10-20 parts of polyether diol, 30-40 parts of p-phenylene diisocyanate, 1-2 parts of chain extender, 0.2-0.6 part of antioxidant, 0.2-1 part of coupling agent, 0.02-0.04 part of organic bismuth catalyst and 0.1-0.5 part of organic amine catalyst;

the polycarbonate diol is polycarbonate cyclohexyl dimethanol-1,6 hexanediol diol or polycarbonate cyclohexyl dimethanol-1,4 butanediol diol; the molecular weight of the polycarbonate dihydric alcohol is 400-1000;

the polyester dihydric alcohol is poly adipic acid-1,4 cyclohexyl dimethyl alcohol ester dihydric alcohol or poly adipic acid-ethylene glycol ester dihydric alcohol; the molecular weight of the polyester dihydric alcohol is 3000;

the polyether glycol is polypropylene glycol PPG-400.

2. The oil-acid reaction resistant polyurethane hot melt adhesive according to claim 1, characterized in that the preparation method comprises the following steps:

(1) Adding polyol, a chain extender and an antioxidant into a reaction container, heating and stirring uniformly, removing water in vacuum at 120 ℃ for 120min, and then cooling to 80 ℃ under the protection of nitrogen;