Photocurable thermochromic adhesive, adhesive composition and preparation as well as application thereof

Abstract

Among a photocurable thermochromic adhesive, an adhesive composition and preparation as well as application thereof, the photocurable thermochromic adhesive includes: 20-60 wt. % of acrylic polyurethane, 10-20 wt. % of Bis-GMA, 10-20 wt. % of triethylene glycol dimethacrylic acid, 10-20 wt. % of ethoxylated trimethylolpropane triacrylate, 10-20 wt. % of HEMA, 10-20 wt. % of modified silica, 1-5 wt. % of a photoinitiator component, 1-5 wt. % of BHT, 1-5 wt. % of KH570, and 1-2 wt. % of a thermochromic component. The adhesive of the present invention is colored in vitro and colorless in oral environment, which helps the doctor to easily remove residues on tooth surfaces when adhering and removing brackets.

Claims

1. A photocurable thermochromic adhesive, comprising: 20-60 wt. % of acrylic polyurethane, 5-10 wt. % of bisphenol A glyceride, 10-20 wt. % of triethylene glycol dimethacrylic acid, 10-20 wt. % of ethoxylated trimethylolpropane triacrylate, 10-20 wt. % of hydroxyethyl methacrylate, 1-2 wt. % of a photoinitiator component, 0.1-1 wt. % of dibutylhydroxytoluene, and 0.01-2 wt. % of a thermochromic component.

2. The photocurable thermochromic adhesive, as recited in claim 1, wherein the thermochromic component is selected from a group consisting of a thermochromic dye and/or a composite thereof, a polythiophene thermochromic pigment, and a liquid crystal derivative of cholesterol.

3. The photocurable thermochromic adhesive, as recited in claim 2, wherein the composite of the thermochromic dye consists of a pH-sensitive dye, a color developer and a non-volatile hydrophobic solvent, wherein the color developer is selected from a group consisting of proton-donating compounds; the pH-sensitive dye is selected from a group consisting of spironolactone compounds; and the non-volatile hydrophobic solvent is selected from a group consisting of fatty acids with a melting point of 30-37° C., amides and alcohols.

4. The photocurable thermochromic adhesive, as recited in claim 1, wherein the photoinitiator component is camphorquinone and/or a hydrogen-abstracting photoinitiator.

5. The photocurable thermochromic adhesive, as recited in claim 4, wherein the hydrogen-abstracting photoinitiator is 2-ethylhexyl 4-(dimethylamino)benzoate.

6. The photocurable thermochromic adhesive, as recited in claim 1, further comprising a filler selected from a group consisting of silica, ground glass powder containing heavy metal dust, and prepolymer.

7. A method for preparing the photocurable thermochromic adhesive as recited in claim 6, comprising steps of: (1) mixing the acrylic polyurethane, the bisphenol A glyceride, the triethylene glycol dimethacrylic acid, the ethoxylated trimethylolpropane triacrylate, the hydroxyethyl methacrylate and 3-(methacryloyloxy)propyltrimethoxysilane according to a certain proportion; (2) adding the dibutylhydroxytoluene and the photoinitiator component to a mixture obtained in the step (1); and (3) adding the filler and the thermochromic component to a mixture obtained in the step (2), and stirring to reach a plasticine state which is homogeneous and viscous, thereby obtaining the photocurable thermochromic adhesive.

8. The method, as recited in claim 7, wherein before adding, the thermochromic component is made into a microcapsule composition.

9. An adhesive composition, comprising the photocurable thermochromic adhesive as recited in claim 6 and a photocuring pretreatment agent, wherein the photocuring pretreatment agent comprises 10-20% of bisphenol A glyceride, 20-80% of hydroxyethyl methacrylate, 0.1-2% of the photoinitiator component, 1-5wt. % of 3-(methacryloyloxy)propyltrimethoxysilane, and 0.1-5% of ethanol.

10. An adhesive composition, comprising the photocurable thermochromic adhesive prepared by the method as recited in claim 8 and a photocuring pretreatment agent, wherein the photocuring pretreatment agent comprises 10-20% of bisphenol A glyceride, 20-80% of hydroxyethyl methacrylate, 0.1-2% of the photoinitiator component, 1-5 wt. % of 3-(methacryloyloxy)propyltrimethoxysilane, and 0.1-5% of ethanol.

11. A method for performing orthodontics, comprising a step of using the photocurable thermochromic adhesive as recited in claim 6.

12. A method for performing orthodontics, comprising a step of using the adhesive composition as recited in claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG. 1 illustrates a shear test device used in embodiment 2 of the present invention;

[0049] FIG. 2 is a comparison of a sample 1 obtained in embodiment 3 of the present invention before and after discoloration;

[0050] FIG. 3 is a comparison of a sample 2 obtained in the embodiment 3 of the present invention before and after discoloration;

[0051] FIG. 4 is a comparison of a sample 3 obtained in the embodiment 3 of the present invention before and after discoloration;

[0052] FIG. 5 is a comparison of a sample 4 obtained in the embodiment 3 of the present invention before and after discoloration; and

[0053] FIG. 6 is a shear strength stability test curve according to embodiment 23 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0054] Referring to drawings and embodiments, the present invention will be further illustrated. However, the embodiments and drawings are exemplary only and not intended to be limiting. All reasonable modifications and combinations made within the inventive concept of the present invention shall fall into the protection scope of the present invention.

EMBODIMENT 1

[0055] A thermochromic component is prepared by:

[0056] 1. Thermochromic dyes and/or composite thereof

[0057] (1) mixing thermochromic green (CAS: 29512-46-7) or thermochromic blue (87563-89-1), phenol and hexadecanol at a mass ratio=1:1:100, and then heating until the system is melted; thoroughly mixing the system in a melted state; and

[0058] (2) cooling a mixture obtained in the step (1) to room temperature, and preparing into microcapsules to obtain dark green or dark blue powder.

[0059] 2. Liquid crystal derivative of cholesterol

[0060] (1) mixing cholesterol pelargonate, cholesterol oleyl carbonate, cholesterol acetate and cholesterol benzoate according to a certain mass ratio, and preparing into microcapsules to obtain green powder.

EMBODIMENT 2

[0061] A photocurable thermochromic adhesive for orthodontics is prepared by:

[0062] (1) mixing acrylic polyurethane with a molecular weight of about 1700, Bis-GMA (bisphenol A glyceride), triethylene glycol dimethacrylic acid (CAS: 109-16-0), ethoxylated trimethylolpropane triacrylate (CAS: 28961-43-5), and HEMA (hydroxyethyl methacrylate) according to a certain proportion, until the whole system is fully mixed;

[0063] (2) adding BHT (antioxidant 264) and a photoinitiator component consisting of camphorquinone and 2-ethylhexyl 4-(dimethylamino)benzoate (mass ratio of 1:1.5) into a mixture obtained in the step (1), and thoroughly stirring; and

[0064] (3) adding a filler and the thermochromic component obtained in the embodiment 1 to a mixture obtained in the step (2), and stirring to reach a plasticine state which is homogeneous and viscous, thereby obtaining the adhesive which can be completely cross-linked and cured by curing for 20 s with a medical UV curing light;

[0065] wherein a specific mass ratio of each raw material is: acrylic polyurethane 35 wt. %, Bis-GMA 5 wt. %, triethylene glycol dimethacrylate acid 10 wt. %, ethoxylated trimethylolpropane triacrylate 20 wt. %, HEMA 10 wt. % %, photoinitiator system 2wt. %, BHT 1 wt. %, thermochromic component 1 wt. %, and the balance of fumed silica.

[0066] A photocurable pretreatment agent is prepared by:

[0067] (1) mixing bisphenol A glyceride, hydroxyethyl methacrylate, 3-(methacryloyloxy)propyltrimethoxysilane and ethanol according to a certain proportion and thoroughly stirring; and

[0068] (2) add the same photoinitiator component used in preparation of the photocurable thermochromic adhesive to a mixture obtained in the step (1), thoroughly stirring and avoiding light;

[0069] wherein a specific mass ratio of each raw material is: bisphenol A glyceride 15%, hydroxyethyl methacrylate 75%, photoinitiator component 1%, 3-(methacryloyloxy)propyltrimethoxysilane 4%, and ethanol 5%.

[0070] The final photocurable thermochromic adhesive is a solid adhesive in the plasticine state, which is thermochromic. The photocurable pretreatment agent is a viscous transparent yellow liquid.

EMBODIMENT 3

[0071] Another thermochromic component is prepared according to the process of the embodiment 1, and then the photocurable thermochromic adhesive for orthodontics is prepared according to the process of the embodiment 2, to obtain adhesives shown in FIGS. 2-5. According to color tests, sample 1 showed dark green (C100, Y100) below 22° C., and the color faded and became nearly colorless above 22° C.; sample 2 was dark blue below 22° C. (C100, M100), and the color faded and became nearly colorless above 22° C.; sample 3 showed peacock green (C60, Y25) below 33° C., and the color faded and became nearly colorless above 33° C.; sample 4 showed bright blue (C100, M60) below 33 showed, and the color faded and became nearly colorless above 33° C.

EMBODIMENTS 4-6

[0072] The adhesive is prepared by the method of the embodiment 2, wherein types of the thermochromic component are changed, while other components remain. Results are shown in the following table:

TABLE-US-00001 TABLE 1 test results of thermochromic effect according to the embodiments 4-6 Types of thermochromic component Thermochromic dyes Thermochromic and/or composite dyes and/or Liquid crystal thereof and liquid composite derivative of crystal derivative of Thermochromic Embodiments thereof cholesterol cholesterol effect 4 yes no no Rapid (a few seconds), repeatable 5 no yes no Slow (tens of seconds), repeatable 6 no no yes Normal (over ten seconds), repeatable

EMBODIMENT 7

[0073] Shear strength of the adhesive composition obtained in the embodiment 2 is tested by a device shown in FIG. 1 and the following processes:

[0074] taking anterior teeth from bovine teeth, excise tooth roots under running water with an emery sheet, and cutting into a suitable size that fits a dental cup; then embedding mesial, distal and palatal surfaces of a dental crown with super anhydrite or self-curing resin in the dental cup; exposing a buccal surface of the dental crown to be slightly above a rim of the dental cup;

[0075] grinding the embedded teeth on a grinder with sandpapers from low to high meshes in turn, until tooth surfaces are smooth; and

[0076] cleaning the tooth surfaces with alcohol and drying with oil-free gas;

[0077] evenly applying an acid etchant on the tooth surfaces, etching for 20-30s, then rinsing off the acid etchant with high-speed running water, and then drying the tooth surfaces with high-pressure oil-free gas;

[0078] evenly applying the adhesive prepared in the embodiment 1 on a orthodontic flat-bottom metal bracket, and then evenly applying the prepared pretreatment agent on the tooth surfaces; placing the bracket on the tooth surfaces and pressing gently so that the adhesive is pressed evenly, and then removing excess adhesive; and

[0079] irradiating with a medical UV curing light for 20s to complete installation of a bracket sample.

[0080] Multiple samples prepared according to the above processes are tested as follows, and specific test processes are based on 6.5 Adhering Strength Test Method in YY/T 0269-2009 Orthodontic Bracket adhering Materials. Test results of shear adhering strength are as follows:

TABLE-US-00002 TABLE 2 sample shear strength of the embodiment 7 Sample number 1 2 3 4 5 6 Shear strength/MPa 4.7 7.3 6.7 4.6 3.6 7.9 Average ± error/MPa 5.80 ± 1.58

[0081] It can be seen that the adhesive strength for orthodontics prepared in the embodiment 7 is 3.6-7.9 MPa after photocuring for 20s.

EMBODIMENTS 8-14

[0082] Photocurable thermochromic adhesives of the embodiments 8-14 for orthodontics are prepared by:

[0083] (1) mixing acrylic polyurethane with a viscosity of 15000-20000 cps, Bis-GMA, triethylene glycol dimethacrylic acid, ethoxylated trimethylolpropane triacrylate, and HEMA according to a certain proportion, until the whole system is fully mixed;

[0084] (2) adding BHT and a photoinitiator component into a mixture obtained in the step (1), and thoroughly stirring; and (3) adding a filler and the thermochromic component obtained in the embodiment 1 with the thermochromic dyes and/or the composite thereof to a mixture obtained in the step (2), and stirring to reach a plasticine state which is homogeneous and viscous, thereby obtaining the adhesive which can be completely cross-linked and cured by curing for 20s with a medical UV curing light;

[0085] wherein the photocurable pretreatment agent adopts the formula of the embodiment 2. Raw material proportions of the photocurable thermochromic adhesives of each embodiment are shown in Table 3:

TABLE-US-00003 TABLE 3 raw material proportions of the embodiment 8-14 Embodiment Component (wt. %) 8 9 10 11 12 13 14 acrylic polyurethane 20 32 43.5 36.9 53.6 60 47.8 (15000-20000 cps) Bis-GMA 5.6 7.8 9.3 6.5 5 10 8.3 triethylene glycol 12 12.1 13.5 13.6 18.6 19 10.2 dimethacrylate acid ethoxylated 16.5 15.9 15.6 12 17.6 19.7 12 trimethylolpropane triacrylate HEMA 18.6 14.4 10 15.4 20.4 18.5 17.5 fumed silica balance camphorquinone 0.3 1 0.5 0.78 1 0.8 1.5 2-ethylhexyl 4- 1.6 1.5 1 0.45 1 1.2 0.5 (dimethylamino) benzoate BHT 0.1 0.3 0.56 0.49 1 0.78 0.36 thermochromic 0.04 1.36 0.83 1 0.1 1.86 0.65 component

EMBODIMENTS 15-21

[0086] Pretreatment agents are prepared according to the method of the embodiment 2:

TABLE-US-00004 TABLE 4 raw material proportions of the embodiment 15-21 Embodiment Component (wt. %) 15 16 17 18 19 20 21 bisphenol A 11.3 15.6 16.9 18.7 13.2 17.6 14.5 glyceride ethoxylated 56.3 70.9 50.3 35.6 49.6 66.5 40.8 trimethylolpropane triacrylate camphorquinone 0.3 0.53 0.1 0.64 0.92 0.82 0.45 2-ethylhexyl 4- 0.6 1.46 0.3 1.32 1.03 0.64 0.53 (dimethylamino) benzoate 3- 1.3 2.6 3.7 5 4.6 3.5 2.6 (methacryloyloxy) propyltrimethoxysilane ethanol 0.5 1.3 2.1 3.7 5 0.9 1.7 fumed silica balance

[0087] 5

EMBODIMENT 22

[0088] According to the method of the embodiment 7, the adhesive is used together with the pretreatment agent to perform shear strength tests. Results are shown in the following table:

TABLE-US-00005 TABLE 5 shear strength test results Embodiment Strength 8 9 10 11 12 13 14 15 3.8 4.8 3.2 3 6.7 7.3 4.7 16 6 2.6 7.1 5 11 4.2 4.5 17 2.1 6.3 9.6 4.3 8.7 7.5 11.7 18 12.3 8.6 4.5 6.7 2.7 2.1 2.7 19 3.4 2.5 4.1 3.4 6.2 5.8 9.1 20 8.1 6.6 9.7 11.3 5.3 5.7 4.3 21 3.9 3.7 1.7 8.5 10.6 6.4 9.2

[0089] It can be seen from the table that the combination of the embodiments 18 and 8 can optimize the strength.

Embodiment 23

[0090] 50 samples of the optimal combination according to the embodiment 22 were put into artificial saliva, and 10 samples were taken out every 10 days to carry out the shear strength test according to the method of the embodiment 7. Results are shown in FIG. 6.

[0091] It can be seen from FIG. 6 that the shear strength of the optimal combination in the embodiment 22 is finally stabled at about 10 MPa, which meets the clinical strength requirements of orthodontic repair.

[0092] The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby. All technical solutions under the concept of the present invention fall into the protection scope of the present invention. It should be pointed out that for those skilled in the art, improvements and modifications without departing from the principles of the present invention should also be regarded as covered by the protection scope of the present invention.