Photoresponse solvent-free polyurethane-acrylate optical transparent pressure-sensitive adhesive composition and preparation method thereof
Through the design of solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, the current solution is solved by combining coumarin-acrylate monomer and acrylate monomer with photoinitiators and thiol chain transfer agents There is a problem of using organic solvents and curing methods in synthesis of light-responsive adhesives, which achieves the effect of adjusting the bonding strength under ultraviolet light.
Patent Information
- Application Number
- CN202411247986.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2024-12-27
AI Technical Summary
The existing photoresponsive adhesives require the use of organic solvents during the synthesis process, and the curing method is thermal curing, which leads to environmental sensitivity and environmental protection problems, and the adhesive strength cannot be adjusted under external light.
Polyurethane prepolymer co-terminated by coumarin-acrylate monomer, low and high glass transition temperature acrylate monomer, functional acrylate monomer, using solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition The combination of the body, combined with the photoinitiator and the thiol chain transfer agent, was prepared to prepare a transparent pressure-sensitive adhesive that did not require an organic solvent, and adjust the bonding strength under ultraviolet light.
It realizes high viscosity and stability of solvent-free transparent pressure-sensitive adhesive, can maintain stability under natural light, and adjust the bonding strength through ultraviolet light irradiation, solving the problem that traditional adhesives cannot adjust the bonding strength under light.
Smart Images
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of stimulus-responsive optically transparent adhesives, and in particular to a light-responsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition and a preparation method thereof. Background Art
[0002] At present, the strength of traditional adhesive bonding is determined by its initial formula composition, and it is impossible to produce corresponding changes in bonding strength under external stimulation. With the emergence of various complex applications, adhesive materials are required to have adjustable bonding strength to adapt to complex external application environments. Compared with traditional heating stimulation, light has the advantages of non-contact, spatially adjustable, and high efficiency, and is especially used in the electronics field. However, existing photoresponsive adhesives mostly involve solvent synthesis, and organic solvents are required to regulate the coating viscosity, which does not conform to the current trend of green environmental protection. Its initial curing method is thermal curing, and the cured material is sensitive to ambient light and needs to be stored away from light. Summary of the invention
[0003] In order to prepare a solvent-free transparent pressure-sensitive adhesive with good stability, the present application provides a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition and a preparation method thereof.
[0004] In the first aspect, the present application provides a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, which adopts the following technical solution: A photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition. The raw materials of the pressure-sensitive adhesive composition include the following components in parts by weight: 30-70 parts of a coumarin-acrylate monomer co-terminated polyurethane prepolymer, 5-30 parts of a low glass transition temperature acrylate monomer, 5-30 parts of a high glass transition temperature acrylate monomer, 15-40 parts of a functional acrylate monomer, 0.5-2 parts of a photoinitiator, 0.5-2 parts of a thiol chain transfer agent, and 2-5 parts of an antioxidant.
[0005] By adopting the above technical scheme, a transparent pressure-sensitive adhesive composition is obtained by combining a coumarin-acrylate monomer co-terminated polyurethane prepolymer, a low glass transition temperature acrylate monomer, a high glass transition temperature acrylate monomer, and a functional acrylate monomer. The coating viscosity does not require an organic solvent to regulate the coating viscosity, and the bonding strength under different ultraviolet light irradiations can be further adjusted as needed. The addition of an antioxidant makes the transparent pressure-sensitive adhesive composition have better stability under natural light.
[0006] In a specific embodiment, the raw materials of the coumarin-acrylate monomer co-terminated polyurethane prepolymer include a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups, and an acrylic monomer containing a hydroxyl group.
[0007] In a specific embodiment, the hydroxyl-containing acrylic monomer includes one of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate.
[0008] In a specific embodiment, the raw materials of the polyurethane containing a portion of isocyanate groups and a portion of coumarin groups include an active hydrogen-modified coumarin precursor, an aliphatic diisocyanate, and a polyether diol; the active hydrogen-modified coumarin precursor is prepared by modifying hydroxyl or amino groups of 7-hydroxycoumarin or 4-methylumbelliferone; the aliphatic diisocyanate includes one of hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, and the index R value is 1.17-1.60; the polyether diol is a polypropylene oxide diol with a molecular weight of 1000-4000 or a polytetrahydrofuran diol with a molecular weight of 1000-2000.
[0009] In a specific embodiment, the method for preparing the coumarin-acrylate monomer co-terminated polyurethane prepolymer comprises the following steps: The polyether diol is first dehydrated at 110° C. for 2 hours, and then reacted with an active hydrogen-modified coumarin precursor and an aliphatic diisocyanate at 115-130° C. to obtain a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups; The polyurethane containing part of the isocyanate groups and part of the coumarin groups and the acrylic monomer containing the hydroxyl group are reacted at 60° C. for 2-4 hours to obtain the polyurethane prepolymer co-terminated by the coumarin-acrylate monomer.
[0010] By adopting the above technical scheme, the polyether diol is first dehydrated, and then reacted with an active hydrogen-modified coumarin precursor and an aliphatic diisocyanate to obtain a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups. Finally, the polyurethane containing a portion of isocyanate groups and a portion of coumarin groups is reacted with an acrylic monomer containing a hydroxyl group to obtain a coumarin-acrylate monomer co-terminated polyurethane prepolymer.
[0011] In a specific embodiment, the molar ratio of terminal coumarin to acrylate in the polyurethane prepolymer co-terminated with coumarin-acrylate monomer is 0.33-2.
[0012] In a specific embodiment, the molecular weight of the polyurethane containing a portion of isocyanate groups and a portion of coumarin groups is 6000-10000 g / mol.
[0013] In a specific embodiment, the photoinitiator includes one of TPO, photoinitiator 184, and TPO-L.
[0014] In a specific embodiment, the mercaptan chain transfer agent includes one of n-dodecyl mercaptan, 1,4-butanediol bis(3-mercaptobutyrate), and pentaerythritol tetrakis(3-secondary mercaptopropionate).
[0015] In a second aspect, the present application provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, which adopts the following technical scheme: A method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition comprises the following steps: firstly, a polyurethane prepolymer co-terminated by coumarin-acrylate monomer, a low glass transition temperature acrylate monomer, a high glass transition temperature acrylate monomer, and a functional acrylate monomer are stirred and mixed uniformly, then a photoinitiator, a thiol chain transfer agent, and an antioxidant are added, and the stirring and mixing are continued to be uniform to obtain a transparent pressure-sensitive adhesive composition.
[0016] By adopting the above technical scheme, the coumarin-acrylate monomer co-terminated polyurethane prepolymer, the low glass transition temperature acrylate monomer, the high glass transition temperature acrylate monomer, and the functional acrylate monomer are first stirred and mixed uniformly, and then a photoinitiator, a thiol chain transfer agent, and an antioxidant are added, and stirring is continued to obtain a transparent pressure-sensitive adhesive composition with high viscosity and good stability.
[0017] In summary, the present application includes at least one of the following beneficial technical effects: 1. In the present application, the transparent pressure-sensitive adhesive composition obtained by using the combination of the coumarin-acrylate monomer co-terminated polyurethane prepolymer, the low glass transition temperature acrylate monomer, the high glass transition temperature acrylate monomer, and the functional acrylate monomer does not require an organic solvent to regulate the coating viscosity, and its bonding strength under different ultraviolet light irradiation can be further adjusted as needed; the addition of the antioxidant makes the transparent pressure-sensitive adhesive composition have better stability under natural light; 2. In the present application, the polyether diol is first dehydrated, and then reacted with an active hydrogen-modified coumarin precursor and an aliphatic diisocyanate to obtain a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups, and finally the polyurethane containing a portion of isocyanate groups and a portion of coumarin groups is reacted with an acrylic monomer containing a hydroxyl group to obtain a coumarin-acrylate monomer co-terminated polyurethane prepolymer; 3. The method of the present application is to firstly stir and mix the coumarin-acrylate monomer co-terminated polyurethane prepolymer, the low glass transition temperature acrylate monomer, the high glass transition temperature acrylate monomer, and the functional acrylate monomer, and then add a photoinitiator, a thiol chain transfer agent, and an antioxidant, and continue stirring to obtain a transparent pressure-sensitive adhesive composition with high viscosity and good stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is an infrared spectrum diagram used to reflect the transmittance of the polyurethane prepolymer in Preparation Example 1.
[0019] Figure 2 It is an infrared spectrum diagram used to reflect the transmittance of the polyurethane prepolymer in Preparation Example 2.
[0020] Figure 3 It is an infrared spectrum diagram used to reflect the transmittance of the polyurethane prepolymer in Preparation Example 3.
[0021] Figure 4 It is an infrared spectrum diagram used to reflect the transmittance of the polyurethane prepolymer in Preparation Example 4. DETAILED DESCRIPTION
[0022] The present application is further described in detail below with reference to the embodiments.
[0023] All raw materials in the examples can be obtained commercially. The acrylic monomer containing hydroxyl group includes but is not limited to one of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate, and hydroxyethyl acrylate is preferred in this application; the active hydrogen-modified coumarin precursor is prepared by modifying hydroxyl or amino groups of 7-hydroxycoumarin or 4-methylumbelliferone, and 7-hydroxyethoxy-4-methylcoumarin is preferred in this application; the aliphatic diisocyanate includes but is not limited to one of hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, and the index R value is 1.17-1.60, and 7-hydroxyethoxy-4-methylcoumarin is preferred in this application. Isophorone diisocyanate; the polyether diol is a polypropylene oxide diol with a molecular weight of 1000-4000 or a polytetrahydrofuran diol with a molecular weight of 1000-2000, and polypropylene glycol is preferably used in the present application; the photoinitiator includes but is not limited to one of TPO, photoinitiator 184, and TPO-L, and is preferably used in the present application; the thiol chain transfer agent includes but is not limited to one of n-dodecyl mercaptan, 1,4-butanediol bis(3-mercaptobutyrate), and pentaerythritol tetrakis(3-secondary mercaptopropionate), and is preferably used in the present application; the antioxidant model is 264.
[0024] Preparation Example Preparation Example 1 Preparation Example 1 provides a method for preparing a coumarin-acrylate monomer co-terminated polyurethane prepolymer, comprising the following steps: 0.2 mol of polyether diol was first dehydrated at 110°C for 2 hours and added to a three-necked flask, then 0.1 mol of active hydrogen-modified coumarin precursor was slowly added through a feeding funnel, the temperature was raised to 160°C and then cooled to 120°C, and then 0.4 mol of aliphatic diisocyanate was slowly added through a feeding funnel, after reacting for 2 hours, the mixture was naturally cooled to 70°C to obtain a polyurethane containing part of the isocyanate groups and part of the coumarin groups; wherein the polyether diol was polypropylene glycol; the active hydrogen-modified coumarin precursor was 7-hydroxyethoxy-4-methylcoumarin; and the aliphatic diisocyanate was isophorone diisocyanate; 0.05 wt% of dibutyltin dilaurate was added to a three-necked flask, and a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups and 0.3 mol of an acrylic acid monomer containing a hydroxyl group were added and reacted at 60°C for 2 hours to obtain a polyurethane prepolymer co-terminated with coumarin-acrylate monomers, wherein the molar ratio of the terminal coumarin to the acrylate in the polyurethane prepolymer co-terminated with coumarin-acrylate monomers was 0.33, and the number average molecular weight was 4 kg mol -1 , weight average molecular weight is 6kgmol -1 , the dispersion is 1.5, and the infrared spectrum is as follows Figure 1 ; The acrylic monomer containing hydroxyl group is hydroxyethyl acrylate.
[0025] Preparation Example 2 Preparation Example 2 provides a method for preparing a coumarin-acrylate monomer co-terminated polyurethane prepolymer, comprising the following steps: 0.2 mol of polyether diol was first dehydrated at 110°C for 2 hours and added to a three-necked flask, then 0.2 mol of active hydrogen-modified coumarin precursor was slowly added through a feeding funnel, the temperature was raised to 160°C and then cooled to 120°C, and then 0.4 mol of aliphatic diisocyanate was slowly added through a feeding funnel, after reacting for 2 hours, the mixture was naturally cooled to 70°C to obtain a polyurethane containing part of the isocyanate groups and part of the coumarin groups; wherein the polyether diol was polypropylene glycol; the active hydrogen-modified coumarin precursor was 7-hydroxyethoxy-4-methylcoumarin; and the aliphatic diisocyanate was isophorone diisocyanate; 0.05 wt% of dibutyltin dilaurate was added to a three-necked flask, and a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups and 0.2 mol of an acrylic acid monomer containing a hydroxyl group were added and reacted at 60°C for 2 hours to obtain a polyurethane prepolymer co-terminated with coumarin-acrylate monomers, wherein the molar ratio of the terminal coumarin to the acrylate in the coumarin-acrylate monomer co-terminated polyurethane prepolymer was 1, and the number average molecular weight was 4 kg mol -1 , weight average molecular weight is 7 kg mol -1 , the dispersion is 1.6, and the infrared spectrum is as follows Figure 2 ; The acrylic monomer containing hydroxyl group is hydroxyethyl acrylate.
[0026] Preparation Example 3 Preparation Example 3 provides a method for preparing a coumarin-acrylate monomer co-terminated polyurethane prepolymer, comprising the following steps: 0.2 mol of polyether diol was first dehydrated at 110°C for 2 hours and added to a three-necked flask, then 0.2 mol of active hydrogen-modified coumarin precursor was slowly added through a feeding funnel, the temperature was raised to 160°C and then cooled to 120°C, and then 0.375 mol of aliphatic diisocyanate was slowly added through a feeding funnel, and after reacting for 2 hours, the mixture was naturally cooled to 70°C to obtain a polyurethane containing part of the isocyanate groups and part of the coumarin groups; wherein the polyether diol was polypropylene glycol; the active hydrogen-modified coumarin precursor was 7-hydroxyethoxy-4-methylcoumarin; and the aliphatic diisocyanate was isophorone diisocyanate; 0.05 wt% of dibutyltin dilaurate was added to a three-necked flask, and a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups and 0.15 mol of an acrylic monomer containing a hydroxyl group were added and reacted at 60°C for 2 hours to obtain a polyurethane prepolymer co-terminated with coumarin-acrylate monomers, wherein the molar ratio of the terminal coumarin to the acrylate in the polyurethane prepolymer co-terminated with coumarin-acrylate monomers was 1.33, and the number average molecular weight was 4 kg mol -1 , weight average molecular weight is 7kgmol -1 , the dispersion is 1.6, and the infrared spectrum is as follows Figure 3 ; The acrylic monomer containing hydroxyl group is hydroxyethyl acrylate.
[0027] Preparation Example 4 Preparation Example 4 provides a method for preparing a coumarin-acrylate monomer co-terminated polyurethane prepolymer, comprising the following steps: 0.2 mol of polyether diol was first dehydrated at 110°C for 2 hours and added to a three-necked flask, then 0.2 mol of active hydrogen-modified coumarin precursor was slowly added through a feeding funnel, the temperature was raised to 160°C and then cooled to 120°C, and then 0.35 mol of aliphatic diisocyanate was slowly added through a feeding funnel, after reacting for 2 hours, the mixture was naturally cooled to 70°C to obtain a polyurethane containing part of the isocyanate groups and part of the coumarin groups; wherein the polyether diol was polypropylene glycol; the active hydrogen-modified coumarin precursor was 7-hydroxyethoxy-4-methylcoumarin; and the aliphatic diisocyanate was isophorone diisocyanate; 0.05 wt% of dibutyltin dilaurate was added to a three-necked flask, and a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups and 0.1 mol of an acrylic acid monomer containing a hydroxyl group were added and reacted at 60°C for 2 hours to obtain a polyurethane prepolymer co-terminated with coumarin-acrylate monomers, wherein the molar ratio of the terminal coumarin to the acrylate in the polyurethane prepolymer co-terminated with coumarin-acrylate monomers was 2, and the number average molecular weight was 5 kg mol -1 , weight average molecular weight is 9 kg mol -1 , the dispersion is 1.8, and the infrared spectrum is as follows Figure 4 ; The acrylic monomer containing hydroxyl group is hydroxyethyl acrylate. Example
[0028] Example 1 Example 1 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 3, 15g of low glass transition temperature acrylate monomer, 5g of high glass transition temperature acrylic monomer, and 40g of functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of photoinitiator, 1.5g of thiol chain transfer agent, and 2g of antioxidant are added to the stirring tank and continued to stir at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the high glass transition temperature acrylic monomer is isobornyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0029] Example 2 Embodiment 2 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 3, 15g of low glass transition temperature acrylate monomer, 10g of high glass transition temperature acrylic monomer, and 35g of functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of photoinitiator, 1.5g of thiol chain transfer agent, and 2g of antioxidant are added to the stirring tank and continued to stir at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the high glass transition temperature acrylic monomer is isobornyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0030] Example 3 Embodiment 3 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 3, 15g of low glass transition temperature acrylate monomer, 15g of high glass transition temperature acrylic monomer, and 30g of functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of photoinitiator, 1.5g of thiol chain transfer agent, and 2g of antioxidant are added to the stirring tank and continued to stir at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the high glass transition temperature acrylic monomer is isobornyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0031] Example 4 Example 4 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 30g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 3, 5g of low glass transition temperature acrylate monomer, 5g of high glass transition temperature acrylic monomer, and 15g of functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 0.5g of photoinitiator, 0.5g of thiol chain transfer agent, and 2g of antioxidant are added to the stirring tank and continued to stir at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the high glass transition temperature acrylic monomer is isobornyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0032] Example 5 Example 5 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 70g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 3, 30g of low glass transition temperature acrylate monomer, 30g of high glass transition temperature acrylic monomer, and 40g of functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 2g of photoinitiator, 2g of thiol chain transfer agent, and 5g of antioxidant are added to the stirring tank and continued to stir at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the high glass transition temperature acrylic monomer is isobornyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0033] Comparative Example Comparative Example 1 Comparative Example 1 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 1, 20g of a low glass transition temperature acrylate monomer, and 40g of a functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of a photoinitiator, 1.2g of a thiol chain transfer agent, and 2g of an antioxidant are added to the stirring tank and stirred continuously at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0034] Comparative Example 2 Comparative Example 2 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 2, 20g of a low glass transition temperature acrylate monomer, and 40g of a functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of a photoinitiator, 1.2g of a thiol chain transfer agent, and 2g of an antioxidant are added to the stirring tank and stirred at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0035] Comparative Example 3 Comparative Example 3 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 3, 20g of a low glass transition temperature acrylate monomer, and 40g of a functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of a photoinitiator, 1.2g of a thiol chain transfer agent, and 2g of an antioxidant are added to the stirring tank and stirred at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0036] Comparative Example 4 Comparative Example 4 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 4, 20g of a low glass transition temperature acrylate monomer, and 40g of a functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of a photoinitiator, 1.2g of a thiol chain transfer agent, and 2g of an antioxidant are added to the stirring tank and stirred at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0037] Comparative Example 5 Comparative Example 5 provides a method for preparing a photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, comprising the following steps: First, 40g of the coumarin-acrylate monomer co-terminated polyurethane prepolymer in Preparation Example 3, 20g of a low glass transition temperature acrylate monomer, and 40g of a functional acrylate monomer are added to a stirring tank and mixed at a stirring speed of 500r / min for 30min. Then, 1g of a photoinitiator, 1.5g of a thiol chain transfer agent, and 2g of an antioxidant are added to the stirring tank and stirred continuously at a stirring speed of 300r / min for 30min to obtain a transparent pressure-sensitive adhesive composition; wherein the low glass transition temperature acrylate monomer is isooctyl acrylate; the functional acrylate monomer is hydroxyethyl acrylate; the photoinitiator is TPO; and the thiol chain transfer agent is n-dodecyl mercaptan.
[0038] Performance testing Adhesion performance test: The transparent pressure-sensitive adhesive composition in each embodiment and comparative example was coated on a PET film and cured using a 365nm LED cold light source. After curing for 2 minutes, an adhesive film was obtained, and a peel strength test was performed on the adhesive film. The higher the peel strength, the better the adhesion performance of the transparent pressure-sensitive adhesive composition.
[0039] Table 1 Performance test results of transparent pressure-sensitive adhesive composition sample <![CDATA[Peeling strength (N cm -1 )]]> <![CDATA[Peel strength (after UV, N / cm -1 )]]> Example 1 8 3 Example 2 9 1 Example 3 10 1 Example 4 8 3 Example 5 8 3 Comparative Example 1 2 1 Comparative Example 2 5 1 Comparative Example 3 7 2 Comparative Example 4 10 6 Comparative Example 5 8 5 Reference Figure 1-4 It can be seen that after the first step of the reaction, the product -1 There are characteristic peaks near 2260cm -1 The characteristic peaks nearby disappeared, indicating that the coumarin-acrylate monomer co-terminated polyurethane prepolymer was successfully synthesized.
[0040] Combining Table 1, Examples 1-5 and Comparative Examples 1-5, the transparent pressure-sensitive adhesive composition in Examples 1-5 has good adhesive properties, and after UV, the adhesive properties change greatly. It can be seen that when preparing the transparent pressure-sensitive adhesive composition, the polyurethane prepolymer co-terminated with coumarin-acrylate monomer, the low glass transition temperature acrylate monomer, the high glass transition temperature acrylate monomer, and the functional acrylate monomer are used to obtain the transparent pressure-sensitive adhesive composition, which does not contain an organic solvent and has a high viscosity. In addition, its adhesive strength can be adjusted under ultraviolet light irradiation.
[0041] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.
Claims
1. A photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition, characterized in that: The raw materials of the pressure-sensitive adhesive composition include the following components in parts by weight: 30-70 parts of a coumarin-acrylate monomer co-terminated polyurethane prepolymer, 5-30 parts of a low glass transition temperature acrylate monomer, 5-30 parts of a high glass transition temperature acrylate monomer, 15-40 parts of a functional acrylate monomer, 0.5-2 parts of a photoinitiator, 0.5-2 parts of a thiol chain transfer agent, and 2-5 parts of an antioxidant.
2. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 1, characterized in that: The raw materials of the coumarin-acrylate monomer co-terminated polyurethane prepolymer include polyurethane containing part of isocyanate groups and part of coumarin groups, and acrylic monomer containing hydroxyl groups.
3. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 2, characterized in that: The acrylic monomer containing a hydroxyl group includes one of hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxybutyl acrylate.
4. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 2, characterized in that: The raw materials of the polyurethane containing part of the isocyanate groups and part of the coumarin groups include an active hydrogen-modified coumarin precursor, an aliphatic diisocyanate, and a polyether diol; the active hydrogen-modified coumarin precursor is prepared by modifying the hydroxyl group or the amino group of 7-hydroxycoumarin or 4-methylumbelliferone; the aliphatic diisocyanate includes one of hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, and the index R value is 1.17-1.60; the polyether diol is a polypropylene oxide diol with a molecular weight of 1000-4000 or a polytetrahydrofuran diol with a molecular weight of 1000-2000.
5. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 4, characterized in that: The preparation method of the coumarin-acrylate monomer co-terminated polyurethane prepolymer comprises the following steps: The polyether diol is first dehydrated at 110 °C for 2 hours, and then reacted with an active hydrogen-modified coumarin precursor and an aliphatic diisocyanate at 115-130 °C to obtain a polyurethane containing a portion of isocyanate groups and a portion of coumarin groups; A polyurethane containing a part of isocyanate groups and a part of coumarin groups and an acrylic monomer containing a hydroxyl group are reacted at 60°C for 2-4 hours to obtain a polyurethane prepolymer co-terminated with coumarin-acrylate monomers.
6. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 5, characterized in that: The molar ratio of terminal coumarin to acrylate in the polyurethane prepolymer co-terminated by coumarin-acrylate monomer is 0.33-2.
7. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 5, characterized in that: The molecular weight of the polyurethane containing a portion of isocyanate groups and a portion of coumarin groups is 6000-10000 g / mol.
8. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 1, characterized in that: The photoinitiator includes one of TPO, photoinitiator 184, and TPO-L.
9. The photoresponsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to claim 1, characterized in that: The mercaptan chain transfer agent includes one of n-dodecyl mercaptan, 1,4-butanediol bis(3-mercaptobutyrate), and pentaerythritol tetrakis(3-secondary mercaptopropionate).
10. A method for preparing the light-responsive solvent-free polyurethane-acrylate optically transparent pressure-sensitive adhesive composition according to any one of claims 1 to 9, characterized in that: The following steps are involved: First, the polyurethane prepolymer co-terminated by coumarin-acrylate monomer, the low glass transition temperature acrylate monomer, the high glass transition temperature acrylate monomer and the functional acrylate monomer are stirred and mixed uniformly, and then a photoinitiator, a thiol chain transfer agent and an antioxidant are added, and the stirring and mixing are continued to be uniform to obtain a transparent pressure-sensitive adhesive composition.