CN103242787A - Acrylic acid modified water-based polyurethane adhesive and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of chemical adhesives, in particular to an acrylic modified water-based polyurethane adhesive and a preparation method thereof. The preparation of the acrylic modified water-based polyurethane adhesive of the present invention includes the preparation of a prepolymer, neutralization and dispersion, and then adding a bridging agent and an acrylic monomer for polymerization. The acrylic modified water-based polyurethane adhesive is mixed with a water-based curing agent to obtain a two-component water-based polyurethane adhesive. The two-component water-based polyurethane adhesive has the properties of less solvent consumption, high solid content, high viscosity, long and adjustable pot life of the mixture, excellent cohesive force, and low price. It can be used in fabrics, foams, plastics, leather, etc. On the substrate, it has broad application prospects.

Description

A kind of acrylic modified water-based polyurethane adhesive and preparation method thereof

technical field

The invention belongs to the technical field of chemical adhesives, and in particular relates to an acrylic modified water-based polyurethane adhesive and a preparation method thereof.

Background technique

Water-based polyurethane adhesive is a kind of adhesive that uses water as the dispersion medium. It combines the advantages of high cohesion, wear resistance, solvent resistance, and tailorability of polyurethane with the advantages of low VOC content of water-based materials. , can effectively overcome the shortcomings of solvent-based polyurethane adhesives such as flammability, strong odor, toxicity, and difficulty in storage and storage. At the same time, through modification, water-based polyurethane can be endowed with mechanical properties comparable to solvent-based.

With more and more countries promulgating laws and regulations to limit the use of volatile organic compounds in coatings and adhesives, and people paying more and more attention to the environment, especially the safety of the home environment, water-based polyurethane has broad development potential and market. Polyurethane will replace solvent-based polyurethane as the main development direction of polyurethane coatings and adhesives in the future. At present, in the automotive interior industry and the shoemaking industry, the adhesives used are mainly solvent-based adhesives, and a large amount of toxic gases will be generated during their use. Especially the leather and foam used in middle and low-end cars mainly use solvent-based adhesives, which cause odor in the compartment and seriously affect health. At the same time, the water-based polyurethane on the market is mainly foreign products, and the price is relatively expensive, so the water-based polyurethane adhesive has a huge market prospect.

One-component waterborne polyurethane has the disadvantages of low solid content and low viscosity, resulting in slow drying and film formation, poor coating performance and difficult construction. At the same time, the reduction of solid content will lead to an increase in transportation costs. Chinese patent CN101456942A discloses a one-component water-based polyurethane modified by diethylenetriamine cross-linking with a chain extender such as adipic dihydrazide, which increases the solid content, but the viscosity is only 13-19 seconds. It leads to difficult construction, poor coating performance and low initial tack. Chinese patent CN101993677 discloses a water-based polyurethane with butanediol chain extension, but its viscosity is low and needs to be adjusted by adding a thickener. The operation is troublesome and complicated, and the addition of ammonia water is likely to bring volatile odor. Chinese patent CN102786651A uses a two-step method to prepare acrylic polyurethane blends. The process is complicated, and no bridging agent is used. Waterborne polyurethane and acrylate are simply blended. The compatibility of the two phases is poor, and the respective properties of polyurethane and acrylate cannot be fully utilized. Performance advantages, and very low viscosity. U.S. Patent No. 5,173,526 uses butyl acrylate, styrene, and a bridging agent vinyldiamine for copolymerization modification, but this method consumes a large amount of -NCO groups, which reduces the cohesive force. US Patent No. 4870129 discloses a water-based polyurethane adhesive product with a solid content of 40-50%, but the hydrophilic group adopts the sulfonic acid diamine type, which needs to add a large amount of solvent, and consumes a lot of energy during recovery.

On the basis of one-component water-based polyurethane, researchers have developed a two-component water-based polyurethane system. Only by cross-linking and modifying with external linking agent can the mechanical properties comparable to those of solvent-based ones be obtained, and water resistance, heat resistance and corrosion resistance can be improved. sex etc. Chinese patent CN102167798A discloses a two-component waterborne polyurethane, but the dispersion uses as much as 58% deionized water, the solid content of the system is low, and a large amount of acetone is used as the curing agent. U.S. Patent No. 6,235,384 uses aziridine as an external linking agent, but it will start to react immediately when the two components are mixed, resulting in a short pot life and affecting construction. US Patent WO9145475A1 discloses a two-component system using HDI trimer as a curing agent, but its dispersion has not been compounded and modified, and the curing agent has not been sealed, and the pot life is not long.

Contents of the invention

The object of the present invention is to provide a kind of acrylic modified water-based polyurethane adhesive with high solid content, strong cohesive force and long pot life and its preparation method.

The acrylic modified water-based polyurethane adhesive provided by the present invention has the following raw material components by weight: 25-50 parts of polyester polyol, 12-25 parts of diisocyanate, 3-7 parts of hydrophilic chain extender, three 3-5 parts of ethylamine, 8-20 parts of bridging agent, 20-50 parts of butyl acrylate, 10-20 parts of acrylate monomers such as methyl methacrylate, 100-200 parts of deionized water, tin catalyst 0.1-0.2 parts, 0.5-1 part of oil-soluble initiator, and 15-35 parts of acetone or N-methylpyrrolidone.

The water-based curing agent contains a hydrophilic group, a cross-linking agent with trimethylol, and a blocking agent.

The acrylic acid modified water-based polyurethane adhesive provided by the invention, the specific preparation steps are:

React polyester polyol, diisocyanate and tin catalyst (such as dibutyltin dilaurate) at 60-90°C for 2-3 hours, then add hydrophilic chain extender and react for 2-3 hours to obtain prepolymer In the reaction process, acetone or N-methylpyrrolidone is added to reduce the viscosity;

Add butyl acrylate and triethylamine, and stir for 0.5 to 1 hour;

Add bridging agent, methyl methacrylate and other acrylate monomers and mix evenly, add initiator, react at 60-70°C for 2-3 hours; remove solvent and monomer in vacuum to obtain high solid content and high viscosity Acrylic modified waterborne polyurethane adhesive.

In the present invention, the polyester polyol can be selected from a polyester polyol with a hydroxyl value of 53-130 mgKOH/g and a molecular weight of 500-5000, especially one or several of the following: ethylene glycol oxalate , Diethylene glycol oxalate, butylene glycol oxalate, ethylene glycol glutarate, neopentyl glycol glutarate, diethylene glycol adipate, adipic diethylene glycol Ethylene Glycol Adipate, Butylene Glycol Adipate, Neopentyl Glycol Adipate, Hexylene Glycol Terephthalate, Butylene Glycol Phthalate. The present invention preferably selects the following one: diethylene glycol adipate, ethylene glycol adipate, neopentyl glycol adipate, butylene adipate, trimethylolpropane Adipate.

In the present invention, the diisocyanate is one or two of the following: diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene Diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), tetramethylcyclohexylmethane diisocyanate (TMXDI). The present invention preferably selects MDI, a kind of IPDI.

In the present invention, the hydrophilic chain extender is an anionic hydrophilic chain extender containing 1 to 2 -CH ₂ OH groups and 1 to 2 -COOH groups, especially: dimethylol Propionic acid, dimethylolbutyric acid, or tartaric acid. The present invention preferably selects dimethylolpropionic acid.

Among the present invention, described bridging agent, its structural formula is:

                                                  

Wherein, x is 0-1, and y is 2-3. The present invention preferably selects the following one: hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

In the present invention, the acrylate monomers are two or more of the following: methyl methacrylate, butyl acrylate, glycidyl acrylate, vinyl acetate, ethyl acrylate, methyl acrylate, methyl Butyl acrylate, glycidyl methacrylate, hexyl methacrylate, butyl methacrylate.

The present invention also provides the water-based curing agent used in conjunction with the acrylic acid-modified water-based polyurethane adhesive, and the water-based curing agent is prepared by the following steps:

React 10-20 parts of diisocyanate and 2-5 parts of hydrophilic chain extender at 60-90°C for 2-3 hours; then add 1-4 parts of cross-linking agent containing trimethylol to react for 2- After 3 hours, add 2 to 5 parts of blocking agent to react for 2 to 4 hours, and finally cool down to neutralize and disperse.

Among the present invention, described trimethylol crosslinking agent, its structural formula is:

 

 

Wherein, X is 0-3, specifically one of the following: trimethylolethane, trimethylolpropane, trimethylolbutane, trimethylolpentane. The present invention preferably selects trimethylolpropane.

In the present invention, the blocking agent is one of the following: caprolactam, methylacetamide, succinimide, phenol, methyl ethyl ketone oxime, acetone oxime, cyclohexanone oxime, ethyl acetoacetate, propylene glycol monomethyl ether , Methanol, Butanol, Pentanol, Bisulfite. The preferred blocking agent of the present invention is methyl ethyl ketone oxime.

The present invention also provides the application of the acrylic-modified water-based polyurethane adhesive, which is to mix the acrylic-modified water-based polyurethane adhesive with the water-based curing agent to form a high-performance two-component water-based polyurethane adhesive. Calculated, the amount of water-based curing agent is 5-30% of the amount of acrylic modified water-based polyurethane.

The acrylic modified water-based polyurethane adhesive prepared by the invention has the appearance of light blue transparent liquid or milky white liquid, the solid content is greater than 40%, and the viscosity is 30-200 seconds.

The water-based solidifying agent prepared by the present invention has the appearance of transparent viscous liquid or milky white liquid.

Compared with prior art, the present invention has following advantage:

Solid content, high viscosity, long pot life of the mixture, such as coating -4 cup viscosity at 25 ℃, the viscosity is 30-200 seconds, and the pot life is as long as 8 hours; strong initial adhesion, excellent final adhesion, and good room temperature curing performance. The production process is simple, the amount of organic solvent is small, and it has excellent adhesion to various substrates such as foam, leather, fabric, and plastic sheets, and has broad application prospects in the automotive interior industry and shoemaking industry.

Detailed ways

Several preferred embodiments of acrylic acid modified water-based polyurethane adhesive and water-based curing agent of the present invention are provided below, and it should be pointed out that formula changes can also be made within the scope of the present invention, and these changes should also be considered as part of the present invention. protected range.

Synthesis of Acrylic Modified Waterborne Polyurethane Adhesive:

Example 1:

25 parts of diethylene glycol adipate with a molecular weight of 2000 were passed over _N2 at 120°C to remove water. Add 11 parts of isophorone diisocyanate, 2‰ parts by mass of dibutyltin dilaurate and react at 85°C for 2 hours, then add 9 parts by mass of dimethylol propionic acid and react for 2 hours to obtain a prepolymer. Add 20 parts of acetone according to the viscosity in the reaction.

Cool down to below 75°C and add 25 parts of butyl acrylate, then add 2.7 parts of triethylamine for neutralization for 1 hour. Add 8 parts of hydroxyethyl methacrylate and 8 parts of methyl methacrylate, and add 100 parts of deionized water for emulsification. 1% by mass of azobisisobutyronitrile was added and reacted at 70° C. for 2 hours. After vacuum distillation, the product can be obtained, and its properties are as follows: solid content 42%, 25°C -4 cup viscosity 180 seconds.

Example 2:

12 parts of diethylene glycol adipate with a molecular weight of 900 were passed through _N2 at 100°C to remove water. Add 11 parts of isophorone diisocyanate, 2‰ mass parts of dibutyltin dilaurate and react at 85°C for 2 hours, then add 9% mass parts of dimethylol propionic acid and react for 2 hours to obtain a prepolymer. 15 parts of nitrogen-methylpyrrolidone were added to the reaction.

Cool down to below 75°C and add 20 parts of butyl acrylate, then add 2.8 parts of triethylamine for neutralization for 1 hour. Add 9 parts of hydroxyethyl methacrylate and 13 parts of methyl methacrylate, and add 100 parts of deionized water for emulsification. 1% by mass of azobisisobutyronitrile was added and reacted at 70° C. for 2 hours. After vacuum distillation, the product can be obtained, and its properties are as follows: solid content 45.9%, 25°C -4 cup viscosity 41 seconds.

Example 3:

25 parts of neopentyl glycol adipate with a molecular weight of 1000 were dehydrated by passing _N2 at 120 °C. Add 11 parts of isophorone diisocyanate, 2‰ parts by mass of dibutyltin dilaurate and react at 85°C for 2 hours, then add 9 parts by mass of dimethylol propionic acid and react for 2 hours to obtain a prepolymer. Add 20 parts of acetone according to the viscosity in the reaction.

Cool down to below 75°C and add 27 parts of butyl acrylate, then add 2.8 parts of triethylamine for neutralization for 1 hour. Add 8 parts of hydroxyethyl methacrylate and 6 parts of methyl methacrylate, and add 100 parts of deionized water for emulsification. 1% by mass of azobisisobutyronitrile was added and reacted at 70° C. for 2 hours. After vacuum distillation, the product can be obtained, and its properties are as follows: 25 ° C - 4 cup viscosity 146 seconds.

Example 4:

25 parts of diethylene glycol oxalate were passed through _N2 at 120°C to remove water. Add 12 parts of diphenylmethane diisocyanate and react at 75° C. for 2 hours, then add 9 parts by mass of dimethylol propionic acid and react for 2 hours to obtain a prepolymer. Add 30 parts of acetone according to the viscosity situation in the reaction.

Cool down to below 60°C and add 25 parts of butyl acrylate, then add 2.7 parts of triethylamine for neutralization for 5 minutes. Add 8 parts of hydroxyethyl methacrylate and 8 parts of methyl methacrylate, and then emulsify with 130 parts of deionized water. 1% by mass of azobisisobutyronitrile was added and reacted at 60° C. for 2 hours. After vacuum distillation, the product can be obtained, and its properties are as follows: 25 ° C - 4 cup viscosity of 96 seconds.

Example 5:

20 parts of butanediol oxalate was passed over _N2 at 100 °C to remove water. Add 9 parts of hexamethylene diisocyanate and react at 90° C. for 2 hours, then add 9 parts by mass of dimethylol butyric acid and react for 2 hours to obtain a prepolymer. Add 18 parts of acetone according to the viscosity situation in the reaction.

Cool down to below 75°C and add 25 parts of butyl acrylate, then add 2.8 parts of triethylamine for neutralization for 10 minutes. Add 8 parts of hydroxypropyl methacrylate and 8 parts of butyl methacrylate, and then emulsify with 95 parts of deionized water. 1% by mass of azobisisobutyronitrile was added and reacted at 65° C. for 2 hours. After vacuum distillation, the product can be obtained, and its properties are as follows: 25°C, -4 cup viscosity, 35 seconds.

Embodiment 6:

25 parts of neopentyl glycol adipate were dehydrated under _N2 at 120 °C. Add 11 parts of isophorone diisocyanate and react at 80° C. for 2 hours, then add 9 parts by mass of dimethylol butyric acid and react for 2 hours to obtain a prepolymer. Add 20 parts of acetone according to the viscosity in the reaction.

Cool down to below 75°C and add 25 parts of ethyl acrylate, then add 2.8 parts of triethylamine for neutralization for 10 minutes. Add 8 parts of hydroxypropyl methacrylate and 8 parts of butyl methacrylate, and add 100 parts of deionized water for emulsification. 1% by mass of azobisisobutyronitrile was added and reacted at 65° C. for 2 hours. After vacuum distillation, the product can be obtained, and its properties are as follows: 25 ° C - 4 cup viscosity 53 seconds.

Synthesis of water-based curing agent:

Embodiment 7:

11 parts of isophorone diisocyanate and 2.7 parts of dimethylolpropionic acid were reacted at 85° C. for 2 hours, and then 1.3 parts of trimethylolpropane were added to react for 2 hours. Lower the temperature and add methyl ethyl ketoxime equivalent to the amount of residual -NCO, and react at 80°C for 3 hours, add triethylamine at room temperature for neutralization for 30 minutes, add 20ml of water for emulsification, and add 10 parts of acetone according to the viscosity during the reaction. The product can be obtained by distillation under reduced pressure.

Embodiment 8:

12 parts of diphenylmethane diisocyanate and 2.6 parts of dimethylol propionic acid were reacted at 60° C. for 2 hours, and 1.2 parts of trimethylolpropane were added to react for 2 hours. Lower the temperature and add methyl ethyl ketoxime equivalent to the amount of residual -NCO and react at 60°C for 3 hours, add triethylamine at room temperature for 5 minutes, add 30ml of water for emulsification, and add 12 parts of acetone according to the viscosity during the reaction. The product can be obtained by distillation under reduced pressure.

Embodiment 9:

11 parts of isophorone diisocyanate and 2.7 parts of dimethylolpropionic acid were reacted at 85° C. for 2 hours, and then 1.2 parts of trimethylolpentane were added to react for 2 hours. Lower the temperature and add acetone oxime equivalent to the amount of residual -NCO and react at 60°C for 3 hours, add triethylamine at room temperature for neutralization for 10 minutes, add 20ml of water for emulsification, and add 10 parts of acetone according to the viscosity during the reaction. The product can be obtained by distillation under reduced pressure.

Example 10:

9 parts of hexamethylene diisocyanate and 2.7 parts of dimethylol butyric acid were reacted at 85° C. for 2 hours, and 1.2 parts of trimethylolbutane were added to react for 2 hours. Lower the temperature and add acetone oxime equivalent to the amount of residual -NCO and react at 60°C for 3 hours, add triethylamine at room temperature for neutralization for 10 minutes, add 20ml of water for emulsification, and add 10 parts of acetone according to the viscosity during the reaction. The product can be obtained by distillation under reduced pressure.

Mix the dispersions obtained in the above-mentioned Examples 1-6 with the curing agent obtained in Examples 7-10 at a mass ratio of 100:20, and mix them evenly to obtain good initial adhesion, good coating performance, and a pot life greater than 8-hour two-component water-based polyurethane adhesive. Excellent final adhesion when fully dried. It can be applied to the bonding of foam, leather, fabric, plastic and other substrates.

Claims (10)

1. the preparation method of acrylic modified waterborne polyurethane binder, it is characterized in that material component counts by weight: 25～50 parts of polyester polyols, 12～25 parts of vulcabond, 3～7 parts of hydrophilic chain extenders, 3～5 parts of triethylamines, 8～20 parts of bridging agents, 20～50 parts of butyl acrylates, 10～20 parts of acrylic ester monomers such as methyl methacrylate, 100～200 parts of deionized waters, 0.1～0.2 part of tin class catalyzer, 0.5～1 part of oil-soluble initiator, and 15～35 parts of acetone or N-Methyl pyrrolidone; Concrete preparation process is:

With polyester polyol, vulcabond, catalyzer reacted 2～3 hours down at 60～90 ℃, added wetting ability chainextender reaction 2～3 hours again, made prepolymer, added acetone or N-Methyl pyrrolidone in the reaction process to reduce viscosity;

Add butyl acrylate, triethylamine stirred 0.5～1 hour;

Add acrylic ester monomers such as bridging agent, methyl methacrylate and mix, add initiator, reacted 2～3 hours down at 60～70 ℃; Vacuum desolventizing and monomer namely obtain high solids content, full-bodied acrylic modified waterborne polyurethane binder.

2. the preparation method of acrylic modified waterborne polyurethane binder according to claim 1, it is characterized in that in the material component, polyester polyol is following one or several: oxalic acid glycol ester, oxalic acid glycol ether ester, oxalic acid butanediol ester, EGG ethylene glycol glutarate, the pentanedioic acid DOPCP, hexanodioic acid glycol ether ester, ethylene glycol adipate(EGA), di-isooctyladinpate, terephthalic acid hexylene glycol ester, the phthalic acid butanediol ester; Hydroxyl value is 53～130mgKOH/g, and molecular weight is 500～5000.

3. the preparation method of acrylic modified waterborne polyurethane binder according to claim 1, it is characterized in that in the material component, vulcabond is following a kind or 2 kinds: diphenylmethanediisocyanate, tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexyl methane diisocyanate, tetramethyl-ring hexyl methane diisocyanate.

4. the preparation method of acrylic modified waterborne polyurethane binder according to claim 1 is characterized in that in the material component, and hydrophilic chain extender contains 1～2-CH ₂The dimethylol propionic acid of OH group and 1～2-COOH group, dimethylolpropionic acid, or tartrate.

5. the preparation method of acrylic modified waterborne polyurethane binder according to claim 1 is characterized in that in the material component, and bridging agent is: Hydroxyethyl acrylate, Propylene glycol monoacrylate, hydroxyethyl methylacrylate, or Rocryl 410.

6. the preparation method of acrylic modified waterborne polyurethane binder according to claim 1, it is characterized in that in the material component that acrylic ester monomer is following 2 kinds or multiple: methyl methacrylate, butyl acrylate, glycidyl acrylate, vinyl-acetic ester, ethyl propenoate, methyl acrylate, butyl methacrylate, glycidyl methacrylate, N-Hexyl methacrylate, butyl methacrylate.

7. acrylic modified waterborne polyurethane binder that is prepared by the described preparation method of one of claim 1-6.

8. the preparation method of a waterborne curing agent is characterized in that the vulcabond with 10～20 parts, and 2～5 parts wetting ability chainextender is 60～90 ℃ of reactions 2～3 hours down; Add 1～4 part of linking agent that contains trishydroxymethyl then and reacted 2～3 hours, the encapsulant that adds 2～5 parts again reacted 2～4 hours, and cooling neutralization at last disperses;

Wherein, described trishydroxymethyl linking agent is following a kind: trimethylolethane, TriMethylolPropane(TMP), tri hydroxy methyl butane, trishydroxymethyl pentane;

Described encapsulant is following a kind: hexanolactam, methylacetamide, succinimide, phenol, methyl ethyl ketoxime, acetoxime, cyclohexanone-oxime, methyl aceto acetate, propylene glycol monomethyl ether, methyl alcohol, butanols, amylalcohol, hydrosulphite.

9. waterborne curing agent that is prepared by the described preparation method of claim 8.

10. double-component waterborne polyurethane tackiness agent, it is characterized in that being formed by the described acrylic modified waterborne polyurethane binder of claim 7 and the described waterborne curing agent mixing of claim 9, by mass, the amount of waterborne curing agent is 5～30% of acrylic acid modified aqueous polyurethane amount.