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CN-122012009-A - Solvent-free castor oil-based polyurethane adhesive and preparation method thereof

CN122012009ACN 122012009 ACN122012009 ACN 122012009ACN-122012009-A

Abstract

The invention discloses a solvent-free castor oil-based polyurethane adhesive and a preparation method thereof, belonging to the technical field of bio-based polyurethane adhesives. The polyurethane adhesive comprises a component A and a component B, wherein the component A comprises, by mass, 5-15 parts of triethanolamine modified castor oil polyol, 5-15 parts of silane modified castor oil, 10-20 parts of polyester polyol, 5-15 parts of polyether polyol, 2-4 parts of isosorbide, 15-25 parts of filler and 0.1-0.2 part of catalyst, and the component B comprises, by mass, 40-60 parts of aliphatic isocyanate, 5-10 parts of isocyanate-based siloxane, 10-20 parts of polyester polyol and 1-6 parts of chain extender. The polyurethane adhesive system does not use an organic solvent, and the raw materials use the bio-based polyol to replace part of petroleum-based polyol, so that the polyurethane adhesive has good environment-friendly sustainability, high strength and high heat resistance.

Inventors

  • ZHANG TONG
  • TONG YANLI
  • KE QIAN
  • CHEN XIN
  • LUO CHENHUI
  • QI MIN
  • HU TINGTING
  • CHEN SHAOFENG

Assignees

  • 美邦（黄山）胶业有限公司

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. A solvent-free castor oil-based polyurethane adhesive, which is characterized by comprising a component A and a component B; the component A comprises the following raw materials in parts by weight: 5-15 parts of triethanolamine modified castor oil polyol, 5-15 parts of silane modified castor oil, 10-20 parts of polyester polyol, 5-15 parts of polyether polyol, 2-4 parts of isosorbide, 15-25 parts of filler and 0.1-0.2 part of catalyst; the component B comprises the following raw materials in parts by mass: 40-60 parts of aliphatic isocyanate, 5-10 parts of isocyanatosiloxane, 10-20 parts of polyester polyol and 1-6 parts of chain extender.
  2. 2. The solvent-free castor oil-based polyurethane adhesive of claim 1, wherein the triethanolamine-modified castor oil polyol is prepared by the steps of: s1, weighing castor oil, triethanolamine and a catalyst, and stirring and mixing; s2, heating to 150 ℃, stirring and reacting for 2-3 hours to obtain the triethanolamine modified castor oil polyol.
  3. 3. A solvent-free castor oil based polyurethane adhesive according to claim 2, wherein the molar ratio of castor oil to triethanolamine is 1:2-3.
  4. 4. The solvent-free castor oil-based polyurethane adhesive of claim 2, wherein the catalyst is one of lead oxide and lithium hydroxide; the catalyst accounts for 0.2 to 0.3 percent of the total mass of the castor oil and the triethanolamine.
  5. 5. The solvent-free castor oil-based polyurethane adhesive of claim 1, wherein the silane-modified castor oil is prepared by the steps of: Step1, weighing castor oil and 3-mercaptopropyl trimethoxy silane, stirring and mixing, adding a photoinitiator UV1173 and acetone into the mixture, and stirring to obtain a reactant; and 2, stirring reactants to react for 6-8h under the condition of room temperature ultraviolet irradiation, and removing acetone by rotary evaporation to obtain silane modified castor oil.
  6. 6. The solvent free castor oil based polyurethane adhesive of claim 5, wherein the molar ratio of castor oil to 3-mercaptopropyl trimethoxysilane is 1:2.4-3.2.
  7. 7. The solvent-free castor oil-based polyurethane adhesive of claim 5, wherein the photoinitiator UV1173 is 0.8-0.9% by mass of castor oil; the acetone is 1.5-2 times of the total mass of the castor oil and the 3-mercaptopropyl trimethoxy silane.
  8. 8. The solvent-free castor oil-based polyurethane adhesive of claim 1, wherein the polyester polyol is at least one of an oxalic acid polyester polyol and an adipic acid polyester polyol; The polyether polyol is at least one of polyoxypropylene glycol, polyoxypropylene triol and polytetrahydrofuran ether glycol.
  9. 9. The solvent-free castor oil-based polyurethane adhesive of claim 1, wherein the isocyanatosiloxane is at least one of propyltriethoxysilane isocyanate and 3-isocyanatopropyltrimethoxysilane.
  10. 10. A process for preparing a solvent-free castor oil-based polyurethane adhesive, characterized in that it comprises the steps of: Step one, preparing a component A raw material in proportion, mixing triethanolamine modified castor oil polyol, silane modified castor oil, polyester polyol, polyether polyol, isosorbide, filler and catalyst, stirring for 2-3 hours at 60-80 ℃, and vacuum defoaming to obtain a component A; step two, preparing a component B raw material according to a proportion, mixing aliphatic isocyanate, isocyanatosiloxane, polyester polyol and a chain extender, stirring and reacting for 3-5h at 80-100 ℃, and vacuum defoaming to obtain the component B.

Description

Solvent-free castor oil-based polyurethane adhesive and preparation method thereof Technical Field The invention belongs to the technical field of bio-based polyurethane adhesives, and particularly relates to a solvent-free castor oil-based polyurethane adhesive and a preparation method thereof. Background Polyurethane adhesives are important in life and industry by virtue of their excellent adhesive properties and wide application fields. It can be used for making various base materials including foam, plastic, wood, leather, fabric, paper and ceramic, etc. and can be used for implementing excellent chemical adhesion of smooth surface of metal, glass and rubber, etc.. The main components of the polyurethane adhesive comprise isocyanate and polyol, and the core reaction mechanism is that isocyanate groups and substances containing active hydrogen react chemically to generate polyurethane groups. This reaction imparts high strength and flexibility to the polyurethane adhesive. Most of polyurethane raw materials are petrochemical products, and with the gradual shortage of petroleum resources and the enhancement of global environment-friendly energy-saving trend, the replacement of petroleum-based raw materials with renewable bio-based raw materials is widely focused on the field of environment-friendly polyurethane materials. Currently, castor oil is an important raw material for producing a bio-based polyurethane adhesive, the castor oil has renewability and biodegradability, and the long carbon chain structure of the castor oil can keep the adhesive layer flexible at-20 ℃, so that the problem of low-temperature embrittlement of the traditional polyurethane adhesive is solved. However, the castor oil has low hydroxyl value and poor reactivity, so that the polyurethane adhesive has low crosslinking density and poor heat resistance, and the wide application of the polyurethane adhesive is severely restricted. Disclosure of Invention The invention aims to provide a solvent-free castor oil-based polyurethane adhesive and a preparation method thereof, which can solve the problem of poor heat resistance of the castor oil-based polyurethane adhesive in the prior art. The aim of the invention can be achieved by the following technical scheme: A solvent-free castor oil-based polyurethane adhesive, which comprises an A component and a B component; the component A comprises the following raw materials in parts by weight: 5-15 parts of triethanolamine modified castor oil polyol, 5-15 parts of silane modified castor oil, 10-20 parts of polyester polyol, 5-15 parts of polyether polyol, 2-4 parts of isosorbide, 15-25 parts of filler and 0.1-0.2 part of catalyst; the component B comprises the following raw materials in parts by mass: 40-60 parts of aliphatic isocyanate, 5-10 parts of isocyanatosiloxane, 10-20 parts of polyester polyol and 1-6 parts of chain extender. In the invention, the biomass conversion material is used for modifying castor oil to replace part of petroleum-based polyester polyol/polyether polyol in the component A of the adhesive, and isosorbide is synchronously added, so that the ratio of the biological base material is improved, and the dependence on petroleum resources is reduced. The triethanolamine modified castor oil polyol has the advantages that the hydroxyl functionality on the molecular chain is larger, compared with a polyurethane network crosslinking structure formed by the reaction of castor oil and isocyanate, the heat resistance is improved, tertiary amine groups are introduced, the hydrolysis crosslinking of siloxane groups is promoted, and the siloxane groups are introduced on the molecular chain of the silane modified castor oil, so that interpenetrating crosslinking network can be formed by utilizing the characteristics of the siloxane groups and the hydrolysis crosslinking of water in air and polyurethane, the crosslinking effect of the adhesive is enhanced, the moisture permeation is hindered, the hydrophobicity of the adhesive after the adhesive is improved, the siloxane groups have stronger affinity to inorganic base materials and inorganic fillers, and the adhesive force of the adhesive can be improved. Isosorbide is added in a high molecular weight polyol system, is also a biological base material, has a dihydric alcohol structure, introduces a rigid alicyclic structure into the polyurethane adhesive, cooperates with a flexible long chain of castor oil, and gives the adhesive better strength and heat resistance while keeping the flexibility of the adhesive. The adhesive of the invention takes the main component of the component B as aliphatic isocyanate, can react with the polyol in the component A to form polyurethane with stable structure, and the isocyanate group siloxane contains isocyanate groups and siloxane groups, can promote the silane modified castor oil in the component A to be compatible with the component B, can react with the polyol and can also realize co-crosslin