High-strength detachable optical adhesive and preparation method thereof
The preparation of polycarbonate polyurethane through isocyanate chain extension method combining specific aliphatic polycarbonate and diisocyanate solves the problem that optical transparent adhesives are difficult to efficiently debond, and high-strength removable optical adhesives are achieved, reducing maintenance and recycling costs and maintaining excellent performance.
Patent Information
- Application Number
- CN202510530894.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-07-11
AI Technical Summary
Existing optical transparent adhesives are difficult to efficiently debond when disassembled, resulting in high maintenance and recycling costs for electronic display screens and optical components, and parts are easily damaged.
Polycarbonate polyurethane is prepared by isocyanate chain extension method using specific aliphatic polycarbonate and specific diisocyanate as raw materials. Combined with excellent light transmission, chemical resistance and adhesive strength, it can be efficiently debonded at an appropriate softening temperature.
High-strength detachable optical adhesive is realized, reducing the maintenance and recycling costs of electronic display screens and optical components, and the components can be recycled, with excellent light transmittance and chemical resistance.
Smart Images
Figure CN120290128A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of special adhesive material preparation, and particularly relates to a high-strength detachable optical adhesive and a preparation method thereof. Background Art
[0002] Optical clear adhesive (OCA) is a special adhesive with high light transmittance and excellent bonding properties, and is widely used in fields that require high transparency and strong adhesion. With the rapid development of the optical and electronic industries, the demand for adhesives with both high transparency and high bonding performance is increasing day by day. Initially, optical clear adhesives were mainly used for bonding optical components, and the high transparency and excellent bonding performance ensured that the optical components maintained high optical performance and stability during assembly and use. For example, in camera lenses, optical clear adhesives are used to bond multiple lenses to ensure that the imaging quality is not affected. With the progress of technology, its application scope has gradually expanded to fields such as electronic displays and the automotive industry.
[0003] In the field of electronic displays, optical clear adhesives are widely used in the manufacture of devices such as liquid crystal displays (LCDs), organic light-emitting diode (OLED) displays, and touchscreens. In the above applications, the adhesive not only needs to have high transparency, but also needs to have excellent weather resistance and chemical resistance to cope with various environmental conditions during the manufacture and use of the display. For example, in the manufacture of touchscreens, optical clear adhesives are used to bond touch sensors and display panels to ensure touch sensitivity and display effects. In the automotive industry, optical clear adhesives are mainly used in the manufacture of in-vehicle displays, optical sensors, and vehicle lights. With the development of intelligent vehicles and autonomous driving technologies, the demand for in-vehicle displays and sensors is increasing, and the application of optical clear adhesives in this field is also becoming increasingly widespread. For example, in the manufacture of in-vehicle displays, optical clear adhesives are used to bond the display screen and the touch panel to ensure display effects and touch sensitivity. In addition, optical clear adhesives are also used in the manufacture of optical accessories such as in-vehicle cameras and lidar, and vehicle lights to ensure their high transparency and stability.
[0004] Currently, the commonly used materials for OCA include acrylate, polysiloxane, epoxy resin, polyurethane, etc. Among them, the light transmittance of polysiloxane and epoxy resin usually cannot reach more than 90%, so they can only be used in basic fields with lower requirements for light transmittance. The light transmittance of acrylate and polyurethane OCA usually can reach more than 90%, and they also have excellent elasticity, impact resistance, chemical resistance and bonding properties, becoming the preferred materials in the OCA field. However, since OCA is usually used in expensive display screens and optical components, it is inevitable that faults will occur during the daily use of display screens and optical components and need to be disassembled and repaired, or they need to be disassembled and recycled after reaching a certain service life. If the OCA used can only provide strong bonding performance and cannot be efficiently debonded when needed, forced debonding will cause great economic losses and even serious industrial accidents due to component failure. Therefore, how to efficiently debond when needed to ensure that the display screen and optical components are not damaged has become a crucial issue, and it is urgent to design and produce high-strength detachable and low-cost OCA. Summary of the Invention
[0005] The purpose of the present invention is to provide a high-strength detachable optical adhesive and its preparation method. By using a specific aliphatic polycarbonate and a specific diisocyanate as raw materials, the isocyanate chain extension method combines the properties of aliphatic polycarbonate and polyurethane to achieve a synergistic effect, so that the prepared polycarbonate-based polyurethane has excellent light transmittance, chemical resistance and bonding strength. At the same time, the polycarbonate-based polyurethane has an appropriate softening temperature. When debonding is needed, only a common hair dryer in daily life needs to be used to heat for 30 s to achieve efficient debonding.
[0006] To achieve the above purpose, the present invention provides the following technical solutions:
[0007] One of the technical solutions of the present invention: Provide a high-strength detachable optical adhesive, and its structural general formula is as follows:
[0008]
[0009] In the above formula, n = 1, 2 or 3; R is
[0010] The asterisk in the R group indicates the position of the connecting bond.
[0011] Another technical solution of the present invention: Provide a preparation method of the above high-strength detachable optical adhesive, including the following steps:
[0012] Prepare polycarbonate diol by using binary carbonate and small molecule diol as raw materials;
[0013] The polycarbonate-based polyurethane is prepared by reacting the polycarbonate diol and the diisocyanate in an organic solvent, which is the high-strength detachable optical adhesive;
[0014] The small molecule diol is 1,4-butanediol, 1,5-pentanediol or 1,6-hexanediol;
[0015] The diisocyanate is isophorone diisocyanate, toluene-2,4-diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate or hexamethylene diisocyanate.
[0016] Preferably, the molar ratio of the binary carbonate to the small molecule diol is 0.8-1.2:1.
[0017] Optionally, the binary carbonate includes dimethyl carbonate, diethyl carbonate or diphenyl carbonate.
[0018] Preferably, when preparing the polycarbonate diol, the catalysts used include tetrabutyl titanate, stannous octoate, dibutyltin dilaurate, potassium tert-butoxide or sodium tert-butoxide.
[0019] More preferably, the addition amount of the catalyst is 0.5-5% of the mass of the binary carbonate.
[0020] Preferably, when preparing the polycarbonate diol, the reaction conditions are to react at 90-120 °C for 8-24 h under an inert atmosphere.
[0021] Optionally, the organic solvent includes N,N-dimethylformamide, acetone, ethyl acetate, butyl acetate, toluene, xylene, dichloromethane or tetrahydrofuran.
[0022] Preferably, the addition amount of the organic solvent is 100-300% of the mass of the polycarbonate diol.
[0023] Preferably, when preparing the polycarbonate-based polyurethane, the catalyst used is an organotin catalyst.
[0024] Optionally, the organotin catalyst includes stannous octoate or dibutyltin dilaurate.
[0025] More preferably, the addition amount of the organotin catalyst is 0.5-2% of the mass of the polycarbonate diol.
[0026] Preferably, when preparing the polycarbonate-based polyurethane, the reaction conditions are to react at 50-80 °C for 4-8 h.
[0027] The third technical solution of the present invention: Provide an application of the above high-strength detachable optical adhesive in an optically transparent adhesive.
[0028] The beneficial technical effects of the present invention are as follows:
[0029] The present invention uses a specific aliphatic polycarbonate and a specific diisocyanate as raw materials, combines the properties of the aliphatic polycarbonate and polyurethane through the isocyanate chain extension method to achieve a synergistic effect, so that the prepared polycarbonate-based polyurethane has excellent light transmittance, chemical resistance and bonding strength. At the same time, the polycarbonate-based polyurethane has an appropriate softening temperature. When debonding is required, only a common hair dryer in daily life needs to be used to heat for 30 s to achieve efficient debonding. The polycarbonate-based polyurethane is a high-strength detachable optical adhesive. Its application as an optically transparent adhesive can greatly reduce the maintenance and recycling costs of electronic displays and optical components. Since the components are not damaged after debonding and can be recycled, the present invention can bring huge economic benefits to the electronic and optical fields.
[0030] In addition, the raw materials used in the present invention are all low-cost chemical raw materials commonly used in the industrial sector, and the prepared adhesive has excellent performance and has the prospect of large-scale production and promotion. Description of the Drawings
[0031] Figure 1 1H NMR spectrum of the polycarbonate diol prepared in Example 1.
[0032] Figure 2 1H NMR spectrum of the polycarbonate-based polyurethane prepared in Example 1.
[0033] Figure 3 1H NMR spectrum of the polycarbonate diol prepared in Example 2.
[0034] Figure 4 1H NMR spectrum of the polycarbonate diol prepared in Example 3.
[0035] Figure 5 Mass loss rate of the high-strength detachable polyurethane optical adhesive prepared in Example 1 after being soaked in different solutions for 60 days.
[0036] Figure 6 Display diagram of the high-strength detachable polyurethane optical adhesive prepared in Example 1 when bonding PC.
[0037] Figure 7 Shear strength of the high-strength detachable polyurethane optical adhesives prepared in Examples 1-11 when bonding PC, PS and PMMA.
[0038] Figure 8 Light transmittance curve of the high-strength detachable polyurethane optical adhesive prepared in Example 1 when bonding PC.
[0039] Figure 9This is a diagram showing the bonding strength when the high-strength detachable polyurethane optical adhesive prepared in Example 1 of the present invention bonds to PC. Detailed Description of the Invention
[0040] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not used to limit the present invention.
[0041] It should be noted that the operations not detailed in the present invention are all conventional operation means in the art and are not the focus of the present invention.
[0042] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.
[0043] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention.
[0044] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.
[0045] Example 1
[0046] Preparation of high-strength detachable polyurethane optical adhesive:
[0047] Add 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol, and 0.34 g of tetrabutyl titanate into a 250 mL three-necked flask, react at 120 °C under nitrogen protection for 24 h, then raise the temperature to 150 °C and perform vacuum distillation for 8 h to ensure that the by-product ethanol can flow out evenly as observed in the early stage. After cooling to room temperature, wash the product with ethanol three times. Dry it in a forced-air drying oven at 60 °C to obtain polycarbonate diol (the nuclear magnetic resonance hydrogen spectrum of which is shown in Figure 1), the number-average molecular weight measured by GPC was 1986; 4 g of polycarbonate diol was placed in a 50 mL three-necked flask, and 8 g of N,N-dimethylformamide, 0.44 g of isophorone diisocyanate, and 20 mg of dibutyltin dilaurate were successively added under a nitrogen atmosphere. After stirring and reacting at 80 °C for 4 h, the mixture was poured onto a polytetrafluoroethylene plate and then cured in a forced-air oven at 80 °C for 24 h to obtain polycarbonate-based polyurethane (the proton nuclear magnetic resonance spectrum is shown in Figure 2 ); the obtained polycarbonate-based polyurethane was injection-molded into a cylindrical glue stick suitable for a hot melt glue gun at 120 °C, and after cooling and demolding, a high-strength detachable polyurethane optical adhesive was prepared;
[0048] The mechanical properties of the prepared product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 42.36 MPa, and an elongation at break of 920%. The bonding performance was tested according to GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively, and the shear strengths were 3.76 MPa, 2.23 MPa, and 2.92 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.07 MPa, 0.04 MPa, and 0.06 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 91% when the sample thickness was 0.3 mm.
[0049] Example 2
[0050] Preparation of high-strength detachable polyurethane optical adhesive:
[0051] 47.2 g of diethyl carbonate, 41.6 g of 1,5-pentanediol, and 0.34 g of tetrabutyl titanate were added to a 250 mL three-necked flask and reacted at 120 °C under nitrogen protection for 24 h. Then, the temperature was raised to 150 °C and vacuum distilled for 8 h to ensure that the by-product ethanol could flow out evenly during the early stage. After cooling to room temperature, the product was washed with ethanol three times. After drying in a forced-air oven at 60 °C, polycarbonate diol was obtained (the proton nuclear magnetic resonance spectrum is shown in Figure 3 ), the number-average molecular weight measured by GPC was 1893; 3.8 g of polycarbonate diol was placed in a 50 mL three-necked flask, and 7.6 g of N,N-dimethylformamide, 0.44 g of isophorone diisocyanate, and 20 mg of dibutyltin dilaurate were successively added under a nitrogen atmosphere. After stirring and reacting at 80 °C for 4 h, the mixture was poured onto a polytetrafluoroethylene plate and then cured in a forced-air oven at 80 °C for 24 h to obtain polycarbonate-based polyurethane; the obtained polycarbonate-based polyurethane was injection-molded into a cylindrical glue stick suitable for a hot melt glue gun at 120 °C, and after cooling and demolding, a high-strength detachable polyurethane optical adhesive was prepared;
[0052] The mechanical properties of the obtained product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 19.75 MPa, and an elongation at break of 1270%. The adhesion properties were tested according to the sample preparation method of GB / T 7124-2008, and three transparent materials, PC, PS, and PMMA, were bonded respectively. The shear strengths were 1.91 MPa, 1.23 MPa, and 1.61 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.03 MPa, 0.03 MPa, and 0.03 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 86% when the sample thickness was 0.3 mm.
[0053] Example 3
[0054] Preparation of a high-strength detachable polyurethane optical adhesive:
[0055] Add 47.2 g of diethyl carbonate, 47.2 g of 1,6-hexanediol, and 0.34 g of tetrabutyl titanate into a 250 mL three-necked flask, react at 120 °C under nitrogen protection for 24 h, then raise the temperature to 150 °C and carry out vacuum distillation for 8 h to ensure that the by-product ethanol can flow out evenly during the early stage. After cooling to room temperature, the product was washed with ethanol three times. After drying in a forced-air drying oven at 60 °C, polycarbonate diol was obtained (its nuclear magnetic resonance hydrogen spectrum is shown in Figure 4 ), and the number-average molecular weight was measured to be 2005 by GPC; take 4 g of polycarbonate diol in a 50 mL three-necked flask, and successively add 8 g of N,N-dimethylformamide, 0.44 g of isophorone diisocyanate, and 20 mg of dibutyltin dilaurate under a nitrogen atmosphere. After stirring and reacting at 80 °C for 4 h, it was poured onto a polytetrafluoroethylene plate, and then cured in an 80 °C forced-air oven for 24 h to obtain polycarbonate-based polyurethane; the obtained polycarbonate-based polyurethane was injection-molded into a cylindrical glue stick suitable for a hot melt glue gun at 120 °C, and after cooling and demolding, a high-strength detachable polyurethane optical adhesive was prepared;
[0056] The mechanical properties of the obtained product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 36.51 MPa, and an elongation at break of 1220%. The adhesion properties were tested according to the sample preparation method of GB / T 7124-2008, and three transparent materials, PC, PS, and PMMA, were bonded respectively. The shear strengths were 3.11 MPa, 2.05 MPa, and 2.42 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.08 MPa, 0.06 MPa, and 0.05 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 90% when the sample thickness was 0.3 mm.
[0057] Example 4
[0058] Preparation of High-Strength Removable Polyurethane Optical Adhesive:
[0059] Add 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 1.32 g of tetrabutyl titanate into a 250 mL three-necked flask. React under nitrogen protection at 120 °C for 24 h, then raise the temperature to 150 °C and carry out vacuum distillation for 8 h to ensure that the by-product ethanol can flow out evenly as observed in the early stage. After cooling to room temperature, wash the product with ethanol three times. Dry it in a forced-air drying oven at 60 °C to obtain polycarbonate diol. The number-average molecular weight measured by GPC is 2015; Take 4 g of polycarbonate diol in a 50 mL three-necked flask. Under a nitrogen atmosphere, sequentially add 8 g of N,N-dimethylformamide, 0.44 g of isophorone diisocyanate, and 20 mg of dibutyltin dilaurate. Stir and react at 80 °C for 4 h, then pour it onto a polytetrafluoroethylene plate, and then cure it in an 80 °C forced-air oven for 24 h to obtain polycarbonate-based polyurethane; Inject the obtained polycarbonate-based polyurethane into a cylindrical glue stick suitable for a hot-melt glue gun at 120 °C. After cooling and demolding, a high-strength removable polyurethane optical adhesive is prepared;
[0060] The mechanical properties of the prepared product are tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 42.07 MPa, and an elongation at break of 920%. The bonding performance is tested according to GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, are bonded respectively, and the shear strengths are 3.76 MPa, 2.24 MPa, and 2.89 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths are 0.07 MPa, 0.04 MPa, and 0.05 MPa respectively. The light transmittance is tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm is 91% when the sample thickness is 0.3 mm.
[0061] Example 5
[0062] Preparation of High-Strength Removable Polyurethane Optical Adhesive:
[0063] 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 0.34 g of tetrabutyl titanate were added to a 250 mL three-necked flask. The reaction was carried out at 120 °C under nitrogen protection for 24 h, and then the temperature was raised to 150 °C for vacuum distillation for 8 h to ensure that the by-product ethanol could flow out evenly in the early stage. After cooling to room temperature, the product was washed three times with ethanol. After drying in a blast drying oven at 60 °C, polycarbonate diol was obtained. The number average molecular weight measured by GPC was 1986; 4 g of polycarbonate diol was taken in a 50 mL three-necked flask. Under a nitrogen atmosphere, 8 g of N,N-dimethylformamide, 0.66 g of isophorone diisocyanate, and 20 mg of dibutyltin dilaurate were added in sequence. After stirring and reacting at 80 °C for 4 h, it was poured onto a polytetrafluoroethylene plate and then cured in a blast drying oven at 80 °C for 24 h to obtain a polycarbonate-based polyurethane; the obtained polycarbonate-based polyurethane was injection molded into a cylindrical glue stick suitable for a hot melt glue gun at 120 °C, and after cooling and demolding, a high-strength detachable polyurethane optical adhesive was prepared;
[0064] The mechanical properties of the prepared product were tested according to ASTM D882, the test speed was 50 mm / min, the tensile strength was 24.05 MPa, and the elongation at break was 720%. The bonding performance was tested according to GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively, and the shear strengths were 2.34 MPa, 1.27 MPa, and 1.96 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.03 MPa, 0.02 MPa, and 0.02 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 91% when the sample thickness was 0.3 mm.
[0065] Example 6
[0066] Preparation of high-strength detachable polyurethane optical adhesive:
[0067] 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 0.34 g of tetrabutyl titanate were added to a 250 mL three-necked flask. The reaction was carried out at 120 °C under nitrogen protection for 12 h, and then the temperature was raised to 150 °C for vacuum distillation for 8 h to ensure that the by-product ethanol could flow out evenly in the early stage. After cooling to room temperature, the product was washed three times with ethanol. After drying in a forced-air drying oven at 60 °C, polycarbonate diol was obtained. The number-average molecular weight measured by GPC was 1326; 2.6 g of polycarbonate diol was taken in a 50 mL three-necked flask. Under a nitrogen atmosphere, 5.2 g of N,N-dimethylformamide, 0.44 g of isophorone diisocyanate, and 20 mg of dibutyltin dilaurate were added in sequence. After stirring and reacting at 80 °C for 4 h, it was poured onto a polytetrafluoroethylene plate, and then placed in a forced-air oven at 80 °C for curing for 24 h to obtain a polycarbonate-based polyurethane; the obtained polycarbonate-based polyurethane was injection-molded into a cylindrical glue stick suitable for a hot-melt glue gun at 120 °C, and after cooling and demolding, a high-strength detachable polyurethane optical adhesive was prepared;
[0068] The mechanical properties of the prepared product were tested according to ASTM D882. The test speed was 50 mm / min, the tensile strength was 38.71 MPa, and the elongation at break was 870%. The bonding properties were tested according to GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively. The shear strengths were 2.85 MPa, 1.64 MPa, and 2.55 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.07 MPa, 0.05 MPa, and 0.06 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 91% when the sample thickness was 0.3 mm.
[0069] Example 7
[0070] Preparation of high-strength detachable polyurethane optical adhesive:
[0071] Add 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 0.34 g of tetrabutyl titanate into a 250 mL three-necked flask, react at 120 °C under nitrogen protection for 24 h, then raise the temperature to 150 °C and distill under reduced pressure for 4 h to ensure that the by-product ethanol can flow out evenly in the early stage. After cooling to room temperature, wash the product with ethanol three times. Dry it in a forced-air drying oven at 60 °C to obtain polycarbonate diol. The number-average molecular weight measured by GPC is 1622; take 3.2 g of polycarbonate diol in a 50 mL three-necked flask, and successively add 6.4 g of N,N-dimethylformamide, 0.44 g of isophorone diisocyanate, and 20 mg of dibutyltin dilaurate in a nitrogen atmosphere. Stir and react at 80 °C for 4 h, then pour it onto a polytetrafluoroethylene plate, and then cure it in an 80 °C forced-air oven for 24 h to obtain a polycarbonate-based polyurethane; inject the obtained polycarbonate-based polyurethane into a cylindrical glue stick suitable for a hot-melt glue gun at 120 °C, and cool and demold to obtain a high-strength detachable polyurethane optical adhesive;
[0072] The mechanical properties of the prepared product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 41.25 MPa, and an elongation at break of 920%. The bonding performance was tested according to GB / T 7124-2008, bonding three transparent materials of PC, PS, and PMMA respectively, and the shear strengths were 3.52 MPa, 2.31 MPa, and 2.99 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.37 MPa, 0.26 MPa, and 0.31 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 91% when the sample thickness was 0.3 mm.
[0073] Example 8
[0074] Preparation of high-strength detachable polyurethane optical adhesive:
[0075] Add 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 0.34 g of tetrabutyl titanate into a 250 mL three-necked flask, react at 120 °C under nitrogen protection for 24 h, then raise the temperature to 150 °C and distill under reduced pressure for 8 h to ensure that the by-product ethanol can flow out evenly in the early stage. After cooling to room temperature, wash the product with ethanol three times. Dry it in a blast drying oven at 60 °C to obtain polycarbonate diol. The number average molecular weight measured by GPC is 1986; take 4 g of polycarbonate diol in a 50 mL three-necked flask, and successively add 8 g of N,N-dimethylformamide, 0.34 g of toluene-2,4-diisocyanate and 20 mg of dibutyltin dilaurate in a nitrogen atmosphere. Stir and react at 80 °C for 4 h, then pour it onto a polytetrafluoroethylene plate, and then cure it in a blast drying oven at 80 °C for 24 h to obtain polycarbonate-based polyurethane; inject the obtained polycarbonate-based polyurethane into a cylindrical glue stick suitable for a hot-melt glue gun at 120 °C, and cool and demold to obtain a high-strength detachable polyurethane optical adhesive;
[0076] The mechanical properties of the prepared product were tested according to ASTM D882, the test speed was 50 mm / min, the tensile strength was 16.55 MPa, and the elongation at break was 680%. The bonding performance was tested according to GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively. The shear strengths were 2.15 MPa, 1.00 MPa, and 1.58 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.06 MPa, 0.04 MPa, and 0.06 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 81% measured with a sample thickness of 0.3 mm.
[0077] Example 9
[0078] Preparation of high-strength detachable polyurethane optical adhesive:
[0079] Add 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 0.34 g of tetrabutyl titanate into a 250 mL three-necked flask, react at 120 °C under nitrogen protection for 24 h, then raise the temperature to 150 °C and distill under reduced pressure for 8 h to ensure that the by-product ethanol can flow out evenly in the early stage. After cooling to room temperature, wash the product with ethanol three times. Dry it in a forced-air drying oven at 60 °C to obtain polycarbonate diol. The number-average molecular weight measured by GPC is 1986; Take 4 g of polycarbonate diol in a 50 mL three-necked flask, and sequentially add 8 g of N,N-dimethylformamide, 0.52 g of dicyclohexylmethane diisocyanate, and 20 mg of dibutyltin dilaurate under a nitrogen atmosphere. Stir and react at 80 °C for 4 h, then pour it onto a polytetrafluoroethylene plate, and then place it in a forced-air oven at 80 °C to cure for 24 h to obtain a polycarbonate-based polyurethane; Inject the obtained polycarbonate-based polyurethane into a cylindrical glue stick suitable for a hot-melt glue gun at 120 °C, and cool and demold to obtain a high-strength detachable polyurethane optical adhesive;
[0080] The mechanical properties of the prepared product were tested according to ASTM D882, the test speed was 50 mm / min, the tensile strength was 31.87 MPa, and the elongation at break was 800%. The bonding performance was tested according to GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively, and the shear strengths were 3.16 MPa, 1.63 MPa, and 2.18 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.06 MPa, 0.04 MPa, and 0.06 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 91% when the sample thickness was 0.3 mm.
[0081] Example 10
[0082] Preparation of high-strength detachable polyurethane optical adhesive:
[0083] 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 0.34 g of tetrabutyl titanate were added to a 250 mL three-necked flask. The reaction was carried out at 120 °C under nitrogen protection for 24 h, and then the temperature was raised to 150 °C for vacuum distillation for 8 h to ensure that the by-product ethanol could flow out evenly in the early stage. After cooling to room temperature, the product was washed with ethanol three times. After drying in a forced-air drying oven at 60 °C, polycarbonate diol was obtained. The number-average molecular weight measured by GPC was 1986; 4 g of polycarbonate diol was taken in a 50 mL three-necked flask. Under a nitrogen atmosphere, 8 g of N,N-dimethylformamide, 0.50 g of diphenylmethane diisocyanate, and 20 mg of dibutyltin dilaurate were added in sequence. After stirring and reacting at 80 °C for 4 h, it was poured onto a polytetrafluoroethylene plate and then cured in a forced-air oven at 80 °C for 24 h to obtain a polycarbonate-based polyurethane; the obtained polycarbonate-based polyurethane was injection-molded into a cylindrical glue stick suitable for a hot-melt glue gun at 120 °C. After cooling and demolding, a high-strength detachable polyurethane optical adhesive was prepared;
[0084] The mechanical properties of the prepared product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 19.21 MPa, and an elongation at break of 470%. The bonding properties were tested according to GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively. The shear strengths were 1.99 MPa, 0.84 MPa, and 1.62 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.03 MPa, 0.02 MPa, and 0.03 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 76% when the sample thickness was 0.3 mm.
[0085] Example 11
[0086] Preparation of high-strength detachable polyurethane optical adhesive:
[0087] Add 47.2 g of diethyl carbonate, 36 g of 1,4-butanediol and 0.34 g of tetrabutyl titanate into a 250 mL three-necked flask. React under nitrogen protection at 120 °C for 24 h, then raise the temperature to 150 °C and carry out vacuum distillation for 8 h to ensure that the by-product ethanol can flow out evenly in the early stage. After cooling to room temperature, wash the product with ethanol three times. Dry it in a forced-air drying oven at 60 °C to obtain polycarbonate diol. The number-average molecular weight measured by GPC is 1986; Take 4 g of polycarbonate diol in a 50 mL three-necked flask. Under a nitrogen atmosphere, add 8 g of N,N-dimethylformamide, 0.33 g of hexamethylene diisocyanate and 20 mg of dibutyltin dilaurate in sequence. Stir and react at 80 °C for 4 h, then pour it onto a polytetrafluoroethylene plate, and then cure it in an 80 °C forced-air oven for 24 h to obtain polycarbonate-based polyurethane; Inject the obtained polycarbonate-based polyurethane into a cylindrical glue stick suitable for a hot-melt glue gun at 120 °C, and cool and demold to obtain a high-strength detachable polyurethane optical adhesive;
[0088] The mechanical properties of the prepared product were tested according to the sample preparation of ASTM D882, the test speed was 50 mm / min, the tensile strength was 12.10 MPa, and the elongation at break was 120%. The bonding performance was tested according to the sample preparation of GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively. The shear strengths were 1.48 MPa, 0.71 MPa, and 1.22 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.18 MPa, 0.09 MPa, and 0.15 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 85% when the sample thickness was 0.3 mm.
[0089] Comparative Example 1
[0090] Preparation of polycarbonate-based polyurethane adhesive:
[0091] Compared with Example 1, the difference is only that 1,4-butanediol is replaced with an equimolar amount of hydroquinone.
[0092] The mechanical properties of the prepared product were tested according to the sample preparation of ASTM D882, the test speed was 50 mm / min, the tensile strength was 65.00 MPa, and the elongation at break was 15%. The bonding performance was tested according to the sample preparation of GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively. The shear strengths were 2.65 MPa, 1.77 MPa, and 2.32 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 2.65 MPa, 1.76 MPa, and 2.32 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 1.2% when the sample thickness was 0.3 mm.
[0093] Comparative Example 2
[0094] Preparation of polycarbonate-based polyurethane adhesive:
[0095] Compared with Example 1, the difference is only that 1,4-butanediol is replaced with an equimolar amount of bisphenol A.
[0096] The mechanical properties of the prepared product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 68.25 MPa, and an elongation at break of 29%. The bonding properties were tested according to GB / T 7124-2008, bonding three transparent materials, PC, PS, and PMMA respectively. The shear strengths were 2.87 MPa, 1.79 MPa, and 2.41 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 2.87 MPa, 1.76 MPa, and 2.41 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 90% when the sample thickness was 0.3 mm.
[0097] Comparative Example 3
[0098] Preparation of polycarbonate-based polyurethane adhesive:
[0099] Compared with Example 1, the difference is only that 1,4-butanediol is replaced with an equimolar amount of 1,8-octanediol.
[0100] The mechanical properties of the prepared product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 32.51 MPa, and an elongation at break of 760%. The bonding properties were tested according to GB / T 7124-2008, bonding three transparent materials, PC, PS, and PMMA respectively. The shear strengths were 2.24 MPa, 1.20 MPa, and 1.95 MPa respectively. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.06 MPa, 0.03 MPa, and 0.05 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 2.4% when the sample thickness was 0.3 mm.
[0101] Comparative Example 4
[0102] Preparation of polycarbonate-based polyurethane adhesive:
[0103] Compared with Example 1, the difference is only that isophorone diisocyanate is replaced with an equimolar amount of p-phenylene diisocyanate.
[0104] The mechanical properties of the obtained product were tested according to the specimen preparation method of ASTM D882, with a test speed of 50 mm / min. The tensile strength was 14.63 MPa, and the elongation at break was 360%. The adhesion performance was tested according to the specimen preparation method of GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively, and the shear strengths were 1.84 MPa, 1.09 MPa, and 1.66 MPa. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.08 MPa, 0.04 MPa, and 0.05 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. When the sample thickness was 0.3 mm, the visible light transmittance at 800 nm was 4.6%.
[0105] Comparative Example 5
[0106] Preparation of polycarbonate-based polyurethane adhesive:
[0107] Compared with Example 1, the difference was only that isophorone diisocyanate was replaced with an equimolar amount of pentamethylene diisocyanate.
[0108] The mechanical properties of the obtained product were tested according to the specimen preparation method of ASTM D882, with a test speed of 50 mm / min. The tensile strength was 9.76 MPa, and the elongation at break was 180%. The adhesion performance was tested according to the specimen preparation method of GB / T 7124-2008. Three transparent materials, PC, PS, and PMMA, were bonded respectively, and the shear strengths were 1.56 MPa, 0.67 MPa, and 1.20 MPa. After heating with a hair dryer at 80 °C for 30 s, the shear strengths were 0.02 MPa, 0.01 MPa, and 0.02 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. When the sample thickness was 0.3 mm, the visible light transmittance at 800 nm was 72%.
[0109] Comparative Example 6
[0110] Preparation of polycarbonate-based polyurethane adhesive:
[0111] Compared with Example 1, the difference was only that isophorone diisocyanate was replaced with an equimolar amount of L-lysine diisocyanate.
[0112] The mechanical properties of the obtained product were tested according to ASTM D882, with a test speed of 50 mm / min, a tensile strength of 28.55 MPa, and an elongation at break of 560%. The adhesion performance was tested according to GB / T 7124-2008, bonding three transparent materials, PC, PS, and PMMA respectively. The shear strengths were 2.68 MPa, 1.59 MPa, and 2.31 MPa respectively. After heating at 80 °C for 30 s with a hair dryer, the shear strengths were 0.03 MPa, 0.01 MPa, and 0.03 MPa respectively. The light transmittance was tested by an ultraviolet spectrophotometer. The visible light transmittance at 800 nm was 3.9% when the sample thickness was 0.3 mm.
[0113] The mass loss rates of the high-strength detachable polyurethane optical adhesive prepared in Example 1 of the present invention after being soaked in different solutions for 60 days are shown in Figure 5 .
[0114] It can be seen from Figure 5 that the high-strength detachable polyurethane optical adhesive prepared in Example 1 has excellent hydrolysis resistance and corrosion resistance, thus having a wider application scenario.
[0115] The display diagram of the high-strength detachable polyurethane optical adhesive prepared in Example 1 of the present invention when bonding PC is shown in Figure 6 .
[0116] The shear strengths of the high-strength detachable polyurethane optical adhesives prepared in Examples 1-8 of the present invention when bonding PC, PS, and PMMA are shown in Figure 7 .
[0117] The light transmittance curve of the high-strength detachable polyurethane optical adhesive prepared in Example 1 of the present invention when bonding PC is shown in Figure 8 .
[0118] The display diagram of the bonding strength of the high-strength detachable polyurethane optical adhesive prepared in Example 1 of the present invention when bonding PC is shown in Figure 9 .
[0119] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.
Claims
1. A high-strength detachable optical adhesive, characterized in that, The structural general formula of the high-strength detachable optical adhesive is as follows: In the above formula, n = 1, 2 or 3; R is 2. The preparation method of the high-strength detachable optical adhesive according to claim 1, characterized in that, It includes the following steps: Prepare polycarbonate diol using binary carbonate and small molecule diol as raw materials; React the polycarbonate diol and diisocyanate in an organic solvent to prepare polycarbonate-based polyurethane, which is the high-strength detachable optical adhesive; The small molecule diol is 1,4-butanediol, 1,5-pentanediol or 1,6-hexanediol; The diisocyanate is isophorone diisocyanate, toluene-2,4-diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate or hexamethylene diisocyanate.
3. The preparation method of the high-strength detachable optical adhesive according to claim 2, characterized in that, The molar ratio of the binary carbonate to the small molecule diol is 0.8 - 1.2:
1.
4. The preparation method of the high-strength detachable optical adhesive according to claim 2, wherein, When preparing the polycarbonate diol, the catalysts used include tetrabutyl titanate, stannous octoate, dibutyltin dilaurate, potassium tert-butoxide or sodium tert-butoxide.
5. The preparation method of the high-strength detachable optical adhesive according to claim 4, wherein The addition amount of the catalyst is 0.5 - 5% of the mass of the binary carbonate.
6. The preparation method of the high-strength detachable optical adhesive according to claim 2, characterized in that, The reaction conditions for preparing the polycarbonate diol are to react at 90 - 120 °C for 8 - 24 h under an inert atmosphere.
7. The preparation method of the high-strength detachable optical adhesive according to claim 2, characterized in that, When preparing the polycarbonate-based polyurethane, the catalyst used is an organotin catalyst.
8. The preparation method of the high-strength detachable optical adhesive according to claim 7, characterized in that The addition amount of the organotin catalyst is 0.5 - 2% of the mass of the polycarbonate diol.
9. The preparation method of the high-strength detachable optical adhesive according to claim 2, characterized in that, The reaction conditions for preparing the polycarbonate-based polyurethane are to react at 50 - 80 °C for 4 - 8 h.
10. Application of the high-strength detachable optical adhesive described in claim 1 in an optical transparent adhesive.