Adhesive composition comprising aramid polymer, and safety glass comprising same

Abstract

The present invention relates to an adhesive composition comprising an aramid polymer, and safety glass manufactured using the adhesive composition, and, more specifically, to: an adhesive composition comprising an aramid polymer, which is colorless and transparent and has excellent mechanical strength and heat resistance, an acrylamide-based monomer, and an initiator; a hybrid film manufactured using the adhesive composition; and safety glass manufactured using the adhesive composition as an intermediate layer. The adhesive composition according to the present invention can provide the safety glass having damping properties against external impact, adhesiveness on glass, high light transmittance, and excellent colorability, and, in particular, is photocurable, and thus enables a manufacturing process that is simpler and production that is more continuous than those of a conventional safety glass containing PVB.

Description

Adhesive composition comprising aramid polymer and safety glass comprising the same

[0001] The present invention relates to an adhesive composition comprising an aramid polymer and safety glass manufactured using the adhesive composition, and more particularly, to an adhesive composition comprising an aramid polymer and an acrylamide-based monomer, which are colorless and transparent and have excellent mechanical strength and heat resistance, a hybrid film manufactured using the adhesive composition, and safety glass manufactured using the adhesive composition as an intermediate layer.

[0002] Laminated glass has long been used as safety glass since its invention in 1936. It is primarily used in automobile windshields and architectural structures, providing resistance to external impacts and preventing flying fragments, thereby preventing injuries. The middle layer, in particular, plays a crucial role in laminated glass. Its required properties include shock absorption, adhesion to glass, and high light transmittance.

[0003] Polyvinyl butyral (PVB) has been used as an interlayer since the first laminated glass (safety glass) was developed, and it remains the most widely used material today. To meet the high market demand, leading global companies have developed products with diverse properties and sold under various brand names. PVB is known to have a terpolymer structure composed of vinyl butyral, vinyl alcohol, and vinyl acetate. When PVB is sandwiched between two sheets of glass and then treated at high temperatures and pressures, it becomes highly transparent and adheres strongly to the glass.

[0004] PVB, commercially available for laminated glass manufacturing, contains various plasticizers, known to control processability and physical properties. While the manufacturing method for laminated glass using PVB as an intermediate layer is well-established, it requires equipment such as an autoclave, making continuous production difficult and requiring skilled labor.

[0005] Although some prior art is known about using UV-curable resins as an intermediate layer in the manufacture of laminated glass, these still appear to be inferior in terms of physical properties compared to conventional PVB-based laminated glass.

[0006] In the prior art, acrylic UV resins manufactured based on methyl methacrylate (MMA) and acrylic acid (AA), which are commonly used monomers, have been reported. Although these acrylic polymers have rarely been developed or commercialized as an intermediate layer for laminated glass, the method of utilizing UV-curable resins will continue to attract more attention in the future because it can make the laminated glass manufacturing process easier and simpler.

[0007] Meanwhile, aramid (aromatic polyamide) is a well-known engineering plastic that boasts not only high chemical and thermal resistance, but also excellent mechanical performance and thermodynamic dimensional stability. This polymer has been developed into films, fibers, and molded products, and is used in products requiring high strength and high modulus. In particular, it has been developed into various composites, including automotive tire cords, bulletproof vests, and as a reinforcing material for cement and concrete.

[0008] However, there has been no disclosure of a hybrid material utilizing an aramid polymer as a reinforcing material of an adhesive composition, i.e., an adhesive composition reinforced with an aramid polymer, particularly a photocurable adhesive composition comprising an aramid polymer, and there has been no report on the use of an adhesive composition comprising the aramid polymer as an intermediate layer of safety glass.

[0009] The present invention aims to provide an adhesive composition capable of satisfying all of the damping against external impact, adhesion to glass, high light transmittance, and excellent colorability required for the middle layer of safety glass, particularly an adhesive composition including an aramid polymer, and safety glass in which glass is bonded to glass using the adhesive composition.

[0010] The present invention provides an adhesive composition comprising an aramid polymer, an acrylamide monomer, and an initiator. The aramid polymer, when combined with the acrylamide monomer, improves mechanical strength, such as tensile strength and elastic modulus, heat resistance, and damping performance against external impact.

[0011] The above aramid polymer can be composed of a colorless and transparent polymer, and therefore the adhesive composition according to the present invention is almost colorless and highly transparent in the visible light range, and thus can provide a colorless and transparent laminated glass.

[0012] The above colorless transparent aramid polymer is selected from 2,2'-bis(trifluoromethyl)benzidine, bis(4-aminophenyl)sulfone, 3-aminophenyl sulfone, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone and one or more diamine compounds and isophthaloyl chloride, terephthaloyl chloride, 4,4'-biphenyldicarbonyl chloride, naphthalene-1,4-dicarbonyl dichloride, 4,4'-oxydibenzoyl chloride, 4,4'-sulfonyldibenzoyl It may be composed of a condensation reaction product of one or more dichlorides selected from chloride, preferably, the diamine compound may include 2,2'-bis(trifluoromethyl)benzidine and bis(4-aminophenyl)sulfone compounds, and the dichloride may include terephthaloyl chloride and isophthaloyl chloride.

[0013] The acrylamide-based compound constituting the adhesive composition according to the present invention may be at least one compound selected from the group consisting of acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, 2-hydroxyethyl methacrylamide, 2-hydroxypropyl methacrylamide, N-vinyl methacrylamide, N-methylmethacrylamide, N,N-dimethylmethacrylamide, N-propylacrylamide, N-butylacrylamide, N,N-dimethylaminopropyl acrylamide, N,N-dimethylaminopropyl methacrylamide, etc., and may preferably be composed of N,N-dimethylacrylamide (DMA).

[0014] The above acrylamide monomer has the same amide structure as the aramid polymer and has very high chemical affinity, so it can dissolve the aramid polymer very well, and in particular, the polymer including DMA strongly adheres to the glass surface through strong hydrogen bonding.

[0015] Therefore, the adhesive composition according to the present invention can be applied to laminated glass to maintain the transparency of the laminated glass while maintaining excellent adhesive strength, and due to the reinforcing effect of the aramid polymer, it has excellent tensile strength and elastic modulus, excellent heat resistance, and high resistance to external impact.

[0016] The initiator constituting the adhesive composition according to the present invention may be composed of a photoinitiator, and therefore has the advantage of a simple manufacturing process and continuous production compared to safety glass containing conventional PVB.

[0017] The adhesive composition according to the present invention may further include a fluorescent dye, thereby enabling the production of safety glass having various colors.

[0018] The present invention provides a method for manufacturing safety glass, comprising the steps of: providing an adhesive composition comprising an aramid polymer, an acrylamide-based monomer, and an initiator; injecting the adhesive composition between glasses; and curing the acrylamide-based compound.

[0019] The method for manufacturing safety glass according to the present invention may further include a step of heat treatment after the step of curing an acrylamide-based compound, and the impact load, light transmittance, and yellowness of the laminated glass may be further improved by the heat treatment.

[0020] The present invention provides an aramid polymer-acrylamide polymer hybrid film manufactured using the above adhesive composition.

[0021] The adhesive composition comprising the aramid polymer according to the present invention is not only almost colorless and highly transparent in the visible light range, but also has excellent miscibility with organic dyes, so that it can impart various fluorescent colors.

[0022] The adhesive composition comprising an aramid polymer according to the present invention has an appropriate viscosity that allows it to be easily applied onto glass, thereby forming a coating layer of a desired thickness, and not only has strong adhesion to glass even after curing, but also does not exhibit any phase separation or spread even after curing, thereby obtaining a colorless and transparent laminated glass.

[0023] The adhesive composition comprising the aramid polymer according to the present invention has excellent tensile strength and elastic modulus and excellent heat resistance due to the reinforcing effect of the aramid polymer, and thus safety glass comprising the same also exhibits high resistance to external impact.

[0024] In particular, the adhesive composition comprising an aramid polymer according to the present invention is photocurable, and thus has the advantage of a simple manufacturing process and continuous production compared to safety glass comprising conventional PVB.

[0025] Figure 1 shows the synthesis route of the aramid polymer used in the present invention.

[0026] Figure 2 (a) schematically illustrates a ball drop test method, and (b) shows the results of a ball drop test on laminated glass samples according to the type and thickness of the intermediate layer used in the laminated glass.

[0027] Figure 3 schematically shows the configuration of an impact load measuring device.

[0028] Figure 4 shows a photograph of a laminated glass manufactured using an intermediate layer containing DCM (yellow), coumarin 6 (green), and perylene (blue) as fluorescent dyes, and the results of spectrofluorometer measurements on the laminated glass.

[0029] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, the singular includes the plural unless specifically stated otherwise. The term "comprises" as used herein does not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0031]

[0032] The present invention aims to provide a colorless and transparent adhesive composition having high mechanical strength, elasticity, and adhesive strength by combining an aramid polymer and an acrylic monomer, laminated glass (safety glass) including the adhesive composition as an intermediate layer, and an aramid-polyacrylamide polymer hybrid film formed by the adhesive composition.

[0033] An adhesive composition comprising an aramid polymer and an acrylic monomer according to the present invention comprises an aramid polymer.

[0034] The above aramid polymer has high elastic modulus and thermodynamic dimensional stability due to chain rigidity and strong hydrogen bonding by aromatic and amide groups.

[0035] The aramid polymer used in the present invention may be colorless and transparent in the visible light range.

[0036] The above aramid polymer can be prepared through a typical low-temperature solution condensation process using aromatic diamines and dicarboxylic acids as monomers.

[0037] As can be seen from the comparison of Kevlar and Nomex, aramid polymers exhibit significant differences in chain flexibility depending on the linkage position of the monomers (para versus meta), which leads to significant differences in their mechanical properties (e.g., modulus) as well as their physicochemical properties (e.g., solubility).

[0038] The adhesive composition according to the present invention comprises an acrylamide monomer. The acrylamide monomer acts as a reactive diluent and can form a matrix through a curing reaction. The acrylamide has the same amide structure as the aramid polymer and has very high chemical affinity, allowing it to dissolve the aramid very well. In particular, N,N-dimethylacrylamide (DMA), unlike other analogues such as acrylamide (solid, melting point 84°C) and N-isopropylacrylamide (abbreviated as NIPAM, solid, melting point 64°C), is liquid at room temperature and can be easily cured using an initiator. Furthermore, polymers prepared from DMA are known to have high adhesive strength, and in fact, DMA polymers strongly adhere to glass surfaces through strong hydrogen bonds. Furthermore, unlike polymers prepared from NIPAM or N,N-diethylacrylamide, DMA polymers do not exhibit thermally induced phase separation (TIPS), allowing them to maintain transparency over a wide temperature range.

[0039] Hereinafter, the synthesis of a colorless transparent aramid polymer and the manufacturing process of an adhesive composition comprising the aramid polymer and an acrylamide-based monomer using the same will be described in detail through examples of the present invention so that those skilled in the art can easily practice the invention, as well as the manufacturing process of a hybrid film and laminated glass (safety glass) manufactured using the adhesive composition, and their physical properties. However, the present invention can be implemented in various different forms and is not limited to the examples described herein.

[0040]

[0041] Synthesis and characterization of colorless transparent aramid polymers

[0042]

[0043] <Manufacture of aramid polymer>

[0044] As illustrated in Fig. 1, a colorless and transparent aramid polymer was prepared using an aromatic diamine and an aromatic dichloride. 2,2'-bis(trifluoromethyl)benzidine (TFMB) having a fluorinated alkyl group (-CF3) and Bis(4-aminophenyl)sulfone (pAPS) having a sulfone group were used as the aromatic diamine, and terephthaloyl chloride (TPC) and isophthaloyl chloride (IPC) were used as the aromatic dichloride.

[0045] In one embodiment, pAPS (10 mmol) as an aromatic diamine was added to a 250 mL three-necked flask equipped with a magnetic bar and filled with nitrogen gas, and dissolved in 35 mL of N,N-dimethylacetamide (DMAc). The flask was immersed in an ice bath and cooled to 0°C, and then TPC (7 mmol) and IPC (3 mmol) dissolved in a small amount of DMAc (5 mL) were added. The mixture was stirred at 0°C for 1 h and at room temperature for 4 h. Finally, the resulting solution was precipitated in a methanol / water (1:1) mixture and filtered to obtain the product. Soxhlet extraction was performed using the same mixture to remove residual HCl, and drying was performed to produce aramid polymer SPA in the form of beads (see Fig. 1).

[0046] Aramid polymer FPA (see Fig. 1) was also prepared using the above method except that TFMB (10 mmol) was used as the aromatic diamine.

[0047]

[0048] In the above example, a dibasic mixture of terephthaloyl chloride (TPC) and isophthaloyl chloride (IPC) at a fixed molar ratio of 70:30 was used to secure the solubility and processability of the aramid polymer.

[0049] Colorless transparency of the aramid polymer was secured by using two compounds, 2,2'-bis(trifluoromethyl)benzidine (TFMB) and bis(4-aminophenyl)sulfone (pAPS), as aromatic diamine monomers. This is because the strong electron-withdrawing effect of the CF3 and sulfone groups effectively suppresses intramolecular charge transfer, and the polymer chains exist in an essentially amorphous state due to the bulky CF3 and sulfone groups, effectively suppressing interchain stacking and preventing intermolecular charge transfer that causes yellowing.

[0050] When a diamine and a dibasic acid chloride are reacted in an ice bath at low temperature using N,N-dimethylacetamide (DMAc) as a solvent, the viscosity of the reaction system increases rapidly within a few minutes, and although HCl is generated as a byproduct, it can be effectively captured through hydrogen bonding such as proton transfer with solvent molecules at low temperature. Therefore, there is no need to add a trapper such as a tertiary amine. After polymerization, the precipitate was precipitated in a methanol / water (1:1) mixture to obtain a white bead-shaped precipitate, and additionally, Soxhlet extraction was performed to obtain a very pure final product in 99% yield. The reason for the high yield of close to 100% is that the nucleophilic acyl substitution reaction effectively occurs between the dibasic acid chloride, which is the most electrophilic among carboxylic acid derivatives, and the aromatic diamine, which has high nucleophilicity but relatively low basicity.

[0051]

[0052] The polymer beads obtained through the above purification process are very stable and solid, have a good appearance, and are easily redissolved in DMAc. This is because both the polymer and the solvent are amide compounds and thus have high chemical affinity for each other.

[0053] The above polymer solution was highly transparent, and these optical properties were also reflected in the film manufactured through the convection drying process, resulting in the production of a colorless and transparent film.

[0054] The aramid polymers obtained in the above bead form were not soluble in THF (tetrahydrofuran), which is mainly used as a GPC solvent, and thus the molecular weight could not be measured using GPC. However, considering that FPA exhibited a high viscosity of over 6000 cP even in DMAc solutions with relatively low concentrations of 10 wt% and 20 wt%, respectively (see Table 1), it is presumed that polymers with considerably high molecular weights were obtained. The viscosity of the polymer solutions was measured at 25°C and 100 rpm using a DV2T viscometer (Brookfield, USA) equipped with a cone-plate spindle CPA-52Z.

[0055]

[0056] <Manufacturing of Aramid Film>

[0057] The aramid polymer beads manufactured above were dissolved in DMAc, cast onto a glass substrate, and sequentially dried in a convection oven at 40°C for 30 minutes, 50°C for 20 minutes, and 200°C for 60 minutes to manufacture a polymer film. The thickness of the film was adjusted to approximately 60 μm.

[0058]

[0059] <Characteristic evaluation of aramid polymers>

[0060] The physical, thermal, mechanical, and optical properties of the above aramid polymer are shown in Table 1.

[0061] Stress-strain curves were measured using the above films using a UTM at a tensile rate of 1 mm / sec. The elastic modulus was measured to be 5.26 GPa for SPA and 8.15 GPa for FPA, and the tensile strength was measured to be 52.6 MPa for SPA and 118.9 MPa for FPA.

[0062] The reason FPA has a higher elastic modulus and tensile strength than SPA is likely because molecular rotation between the two phenyl rings of TFMB is extremely restricted due to steric hindrance induced by the bulky CF3 group. In contrast, the two phenyl rings of pAPS are connected by two single bonds via a sulfur atom with a very large atomic radius, allowing relatively free molecular rotation.

[0063] Thermogravimetric analysis (TGA) of these two polymers revealed that SPA and FPA exhibited a 5% weight loss (Td50%) at 420°C and 460°C, respectively, demonstrating excellent thermal stability. The TGA measurements were performed using a Q500 TGA (TA Instruments, USA) in a nitrogen atmosphere over a temperature range of 25°C to 1000°C at a heating rate of 10°C / min.

[0064] Differential scanning calorimetry (DSC) analysis was performed under a nitrogen atmosphere over the temperature range of 25–400°C at a heating or cooling rate of 10°C / min. SPA exhibited an endothermic change due to the glass transition at a very high temperature of approximately 350°C, whereas FPA showed no change in enthalpy within the measured temperature range. This suggests that FPA exhibits greater thermodynamic stability than SPA. Similar to the differences in mechanical properties between the two polymers, the rigidity of the polymer chains appears to account for the difference in thermodynamic phase transition behavior.

[0065] Therefore, the aramid polymer according to the present invention can be utilized as a reinforcing material capable of imparting thermal stability, thermodynamic dimensional stability, and mechanical strength required for the middle layer of safety glass.

[0066] To measure the transmittance and yellowness of the aramid film, ultraviolet-visible (UV-Vis) spectra were recorded using a JASCO V-650 spectrophotometer (JASCO, Japan).

[0067] Both SPA and FPA films were colorless and transparent, and their light transmittances were quite high at 84.8 and 83.7% at 440 nm, respectively, and their yellowness indices were relatively low at 2.16 and 3.99, respectively.

[0068]

[0069]

[0070] 2. Manufacturing and Characterization of Aramid-PDMA Hybrid Films

[0071]

[0072] N,N-dimethylacrylamide (DMA) was selected as a reactive diluent capable of dissolving the two aramid polymers prepared in step 1 above. Since DMA has a very similar structure to the solvent DMAc, it was expected that the solubility of aramid would be very high, and as expected, both polymers were very soluble in DMA.

[0073] For SPA, when dissolved up to 20 wt%, a viscosity suitable for the coating process (16 cP at 5 wt%, 318 cP at 10 wt%, 2274 cP at 15 wt%, and 13500 cP at 20 wt%) could be obtained. However, at concentrations exceeding 20 wt%, the viscosity increased to a level close to gelation, making it difficult to produce a uniform liquid resin. For FPA, a more significant viscosity increase was observed with increasing content, reaching 36700 cP at 10 wt%, and gelation occurred above that level. (See solution viscosity in Table 2.)

[0074] The viscosity difference between the two polymers is related to the fact that FPA has a much more rigid chain structure than SPA, and the rotational freedom of the polymer chains is closely related to the hydrodynamic chain mobility.

[0075]

[0076] <Manufacturing of Aramid-PDMA Hybrid Film>

[0077] The two aramid polymers and DMA were mixed in the composition ratios shown in Table 2 and stirred overnight until the aramid was completely dissolved in the DMA. Irgacure 500 (1 wt%) as a photoinitiator was added to the solution and stirred for 5 minutes. The mixture solution was injected between two silicone-coated PET release films and UV-cured for 1 hour (≥ 365 nm, UV light intensity: ~ 2 mW / cm2). During UV curing, the PET release film was pressed using the weight of a slide glass to produce an aramid-PDMA hybrid film having a thickness of approximately 100 μm and a uniform thickness. If the PET release film is not used as described above, the aramid-PDMA hybrid film strongly adheres to the glass, making it impossible to obtain an independent film.

[0078] The thermal, mechanical, and optical properties of the above aramid-PDMA hybrid film are shown in Table 2. Comparative Example 1 is a case where DMA is polymerized solely (PDMA).

[0079] In TGA analysis, all hybrid films exhibited less than 10% weight loss up to 350°C. This indicates that not only the aramid polymer but also the matrix polymer, PDMA, is highly thermally stable. Higher aramid polymer content results in greater residual mass above 400°C, due to the higher heat resistance of the aramid.

[0080] In DSC analysis, Tg gradually increased with increasing aramid content. As in Comparative Example 1, Tg was 120°C for the DMA homopolymer, but in the hybrid film, it gradually increased with aramid content, reaching 150°C for Example 4 containing 20 wt% SPA and 128°C for Example 6 containing 10 wt% FPA.

[0081] The gradual increase in Tg with increasing aramid polymer content indicates that the aramid polymer effectively interacts with the matrix polymer, PDMA, through non-covalent interactions such as hydrogen bonding, thereby influencing the thermodynamic mobility of the matrix polymer chains. Furthermore, this confirms that the two polymers, the aramid polymer and PDMA, effectively interact with each other and are well mixed at the molecular level.

[0082] The above aramid-PDMA hybrid films appeared colorless and transparent to the naked eye, and these hybrid films exhibited a light transmittance of 85% or more at 440 nm, which is the edge of the visible light range, and a yellowness index of 3.0 or less, which was considerably low.

[0083] Additionally, the aramid-PDMA hybrid film exhibited much higher tensile strength and elastic modulus than PDMA.

[0084] The tensile strength and elastic modulus of PDMA were 7.1 MPa and 0.7 GPa, respectively. When 5 wt% of FPA was included as in Example 5, they were 30.8 MPa and 2.16 GPa, respectively. When 5 wt% of SPA was included (see Example 1), they were 26.4 MPa and 1.69 GPa, respectively. In other words, adding only 5 wt% of aramid can be said to be very effective in improving the mechanical properties of the hybrid film.

[0085] As the aramid polymer content increased, the tensile strength and elastic modulus further increased, and as a result, when 10 wt% of SPA was included (see Example 2), the tensile strength was 34.2 MPa and the elastic modulus was 2.05 GPa, which were very high values.

[0086] The improvement in mechanical properties due to the addition of aramid polymer means that the two components, aramid polymer and DMA polymer, strongly interact with each other at the molecular level and are very well mixed without structural defects such as phase separation.

[0087] However, in Example 3, where the aramid polymer content was further increased, the elastic modulus and tensile strength decreased somewhat. This means that when the aramid polymer content within the aramid-PDMA hybrid film exceeds a certain amount, vitrification may occur within the film, which can also be confirmed in the impact test results described below.

[0088] The refractive indices of PDMA films and aramid-PDMA hybrid films were measured using an Abbe refractometer (1T(1212), Atago, Japan) according to ISO 18369-4.

[0089] Since it is difficult to measure the refractive index of a film in a dry state, three drops of a refractive index standard solution (PS-RI-10, ParagonScientificLtd.) were dropped on the film surface and pressed into a refractive index instrument for measurement.

[0090] The refractive index of the PDMA film was measured to be 1.497 (see Comparative Example 1), and the refractive index tended to increase with the addition of the aramid polymer, and the range was 1.519 to 1.547.

[0091]

[0092]

[0093] 3. Manufacturing and Characterization of Laminated Glass

[0094] <Manufacturing of Laminated Glass>

[0095] Aramid polymer and DMA were mixed in the composition ratios shown in Table 2 and stirred overnight until the aramid was completely dissolved in the DMA. Irgacure 500 (1 wt%) as a photoinitiator was added to the solution and stirred for 5 minutes.

[0096] The above mixture solution was applied between two glass sheets (thickness: 150 μm, size: 2.4 x 2.4 cm) and UV-cured (≥ 365 nm, UV light intensity: ~ 2 mW / cm2) for 1 hour. The thickness of the intermediate layer was controlled by changing the amount of resin solution applied between the two glasses.

[0097]

[0098] All laminated glasses were very transparent and appeared to have a good appearance, and no bubbles or optical defects were observed in the interlayer (see Table 3). The two sheets of glass were strongly bonded by the interlayer and could not be separated by hand.

[0099]

[0100] <Ball drop test of laminated glass>

[0101] As shown in Fig. 2(a), steel balls of different weights were dropped from a height of 30 cm above laminated glass samples having different intermediate layer thicknesses, and the extent to which the laminated glass samples were broken was observed.

[0102]

[0103] When the weight of the steel ball used in the test was 110 g, a difference in cracks was observed for each sample, and this is shown in Fig. 2 (b). When the ball weight was less than 110 g, no cracks occurred in any sample.

[0104] When PDMA (Comparative Example 1) was used as an intermediate layer, cracks occurred in all three samples regardless of the intermediate layer thickness when a 110 g ball was dropped from a height of 30 cm.

[0105] In the case of the intermediate layer composed of the compositions of Examples 1 and 4, cracks occurred in the laminated glass when the thickness was 150 μm or less, but no cracks occurred when the intermediate layer thickness exceeded 200 μm.

[0106] When an intermediate layer composed of the composition of Example 2 was used, no cracks occurred in the laminated glass regardless of the thickness of the intermediate layer. This indicates that the aramid polymer applied to the intermediate layer can absorb (dam) impact.

[0107] In contrast, cracks occurred in the laminated glass in the intermediate layer of Example 3 at all thicknesses. This is thought to be because, as described above, the intermediate layer became more glassy as the aramid polymer content increased.

[0108] From the above results, it can be seen that it is very important to control the thickness of the intermediate layer and the amount of aramid polymer used as a reinforcing material in order to exhibit an appropriate impact attenuation effect.

[0109] Another noteworthy point is that, regardless of the impact resistance of the laminated glass, even in the case of broken laminated glass samples, the PDMA adheres strongly to the glass, resulting in minimal scattering of fragments. This indicates that the aramid-DMA composition according to the present invention is suitable for manufacturing safety glass that does not scatter even when the glass is broken.

[0110]

[0111] <Measurement of impact load of laminated glass>

[0112] After placing each of the laminated glass samples in which PDMA (Comparative Example 1) was used as an intermediate layer (thickness 100 μm) and the laminated glass samples in which an intermediate layer (thickness 100 μm) composed of the compositions of Examples 2 and 3 was used on a load cell, a 5.6 g steel ball was dropped from a height of 30 cm, and the force applied to the sample upon impact was measured using the Arduino IDE. The Arduino Uno was connected between a computer and a 5 kg straight bar load cell (TAL220B) equipped with an HX711 load cell amplifier (XFW-HX711) as shown in Fig. 3.

[0113] Prior to the impact test, the physical quantity detected by the load cell was converted into load (N) using weights. The steel ball drop test was performed four times on each sample, and the average value and standard deviation were calculated, which are shown in Table 3 (refer to before heat treatment).

[0114]

[0115] When PDMA (Comparative Example 1) was used as the intermediate layer (thickness 100 μm), the impact load was measured to be approximately 0.125 N, and in the case of the intermediate layer containing 10 wt% of SPA (Example 2), it was measured to be 0.113 N. This means that the ability to alleviate external impact is better when aramid is added, and this result is consistent with the test result in the drop test using a 110 g ball.

[0116]

[0117] <Heat treatment of laminated glass>

[0118] A laminated glass sample in which PDMA (Comparative Example 1) was used as an intermediate layer (thickness 100 μm) and a laminated glass sample in which an intermediate layer (thickness 100 μm) composed of the compositions of Examples 2 and 3 was used were heat-treated in a circulating oven at 200°C for 1 hour.

[0119] The impact load, transmittance, and yellowness of the above heat-treated laminated glass samples are shown in Table 3 (reference after heat treatment).

[0120]

[0121] As shown in Table 3, the impact load values ​​were measured to be lower after heat treatment, and this result indicates that the heat treatment temperature is higher than the T of the aramid polymer. gIt is believed that this is because the heat treatment further strengthens the adhesion between the glass and the intermediate layer, as the intermediate layer has some fluidity due to the heat treatment performed at the above temperature. Even after the heat treatment, when SPA was used at 10 wt% as the intermediate layer (Example 2), a lower impact load value was shown compared to when PDMA was used alone or when SPA was used at 15 wt% (Example 3).

[0122] It can also be confirmed that the light transmittance and yellowness of the laminated glass sample are further improved by heat treatment, which is also believed to be the result of increased adhesion between the intermediate layer and the glass.

[0123]

[0124] <Evaluation of the colorability of laminated glass>

[0125] During the manufacturing process of the composition used as the intermediate layer (Example 2 in Table 2), various fluorescent dyes (1 wt%) were added. Using DCM (yellow), coumarin 6 (green), and perylene (blue) as fluorescent dyes, aramid-DMA solutions having various fluorescent colors were manufactured, and laminated glass was manufactured using the same method as described above.

[0126] The fluorescence properties of the above laminated glass samples were observed visually and by fluorescence spectroscopy. Fluorescence spectroscopy was performed using a JASCO FP-6500 spectrofluorometer (JASCO, Japan), with the maximum absorption wavelength of each fluorescent dye as the excitation wavelength.

[0127]

[0128] All of the fluorescent dyes described above were very soluble in DMA, so that fluorescent aramid-DMA solutions could be easily obtained, and laminated glasses having various fluorescent colors could be manufactured, as shown in Fig. 4.

[0129]

[0130] In the above examples, only the cases where 2,2'-bis(trifluoromethyl)benzidine and bis(4-aminophenyl)sulfone are used as aromatic diamines for the synthesis of aramid polymers, and terephthaloyl chloride and isophthaloyl chloride are used as aromatic dibasic acids are described. However, the aramid polymer is not limited as long as it is a colorless and transparent aramid polymer, and one or more compounds selected from aromatic diamine monomers having a fluorinated alkyl group or aromatic diamine monomers having a sulfone group may be used.

[0131] As the aromatic diamine, one or more compounds selected from among 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl] sulfone, m-aminophenylsulfone, etc. may be used, and as the aromatic dichloride, one or more compounds selected from among 4,4'-biphenyldicarbonyl chloride, naphthalene-1,4-dicarbonyl dichloride, 4,4'-oxydibenzoyl chloride, 4,4'-sulfonyldibenzoyl chloride, etc. may be used, but are not limited thereto.

[0132] In addition, although the above examples disclose using DMA as an acrylamide monomer, the acrylamide monomer may be at least one compound selected from the group consisting of acrylamide, N,N-diethylacrylamide, 2-hydroxyethyl methacrylamide, 2-hydroxypropyl methacrylamide, N-vinyl methacrylamide, N-methylmethacrylamide, N,N-dimethylmethacrylamide, N-propylacrylamide, N-butylacrylamide, N,N-dimethylaminopropyl acrylamide, N,N-dimethylaminopropyl methacrylamide, etc., but is not limited thereto.

[0133] And although the above examples describe using a photoinitiator as an initiator, there is no limitation on the initiator as long as it can induce a polymerization reaction or a curing reaction for an acrylamide-based monomer, and it can be selected from thermal polymerization initiators such as azo compounds, organic peroxides, oxidation-reduction initiators including persulfates or hydroperoxides, organometallic compounds, etc.

[0134] The present invention relates to an adhesive composition comprising an aramid polymer and safety glass manufactured using the adhesive composition. The adhesive composition exhibits excellent tensile strength and elastic modulus and excellent heat resistance due to the reinforcing effect of the aramid polymer, and thus safety glass manufactured using the adhesive composition also exhibits high resistance to external impact. Therefore, the present invention has industrial applicability.

Claims

1. An adhesive composition comprising an aramid polymer, an acrylamide monomer, and an initiator.

2. An adhesive composition according to claim 1, wherein the aramid polymer is colorless and transparent.

3. In claim 2, The above colorless transparent aramid polymer is selected from 2,2'-bis(trifluoromethyl)benzidine, bis(4-aminophenyl)sulfone, 3-aminophenyl sulfone, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone and one or more diamine compounds and isophthaloyl chloride, terephthaloyl chloride, 4,4'-biphenyldicarbonyl chloride, naphthalene-1,4-dicarbonyl dichloride, 4,4'-oxydibenzoyl chloride, An adhesive composition characterized in that it is a condensation reaction product of at least one dibasic acid salt selected from 4,4'-sulfonyldibenzoyl chloride.

4. An adhesive composition comprising a colorless transparent aramid polymer, characterized in that, in claim 3, the diamine compound comprises 2,2'-bis(trifluoromethyl)benzidine and bis(4-aminophenyl)sulfone compounds, and the dicarboxylic acid salt comprises terephthaloyl chloride and isophthaloyl chloride.

5. An adhesive composition according to claim 1, wherein the acrylamide-based compound is at least one compound selected from the group consisting of acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, 2-hydroxyethyl methacrylamide, 2-hydroxypropyl methacrylamide, N-vinyl methacrylamide, N-methylmethacrylamide, N,N-dimethylmethacrylamide, N-propylacrylamide, N-butylacrylamide, N,N-dimethylaminopropyl acrylamide, and N,N-dimethylaminopropyl methacrylamide.

6. An adhesive composition according to claim 5, characterized in that the acrylamide-based compound is N,N-dimethylacrylamide.

7. An adhesive composition according to claim 1, characterized in that the initiator is a photoinitiator.

8. An adhesive composition according to claim 1, characterized in that it further comprises a fluorescent dye.

9. A step of providing an adhesive composition according to any one of claims 1 to 8, A step of injecting the above adhesive composition between glasses, A method for manufacturing safety glass, comprising a step of curing the above acrylamide-based compound.

10. A method for manufacturing safety glass according to claim 9, characterized in that it further comprises a step of heat treatment after the step of polymerizing the acrylamide-based compound.

11. An aramid polymer-acrylamide polymer hybrid film manufactured using an adhesive composition according to any one of claims 1 to 8.

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