KR102197042B1 - Adhesive composition for automobility - Google Patents

Abstract

The present invention relates to an adhesive composition for automobiles, and more particularly, to an automobile adhesive composition having low flow properties, excellent shear strength, impact strength and peel strength, and excellent elongation and water resistance without cracking. will be.

Description

Adhesive composition for automobiles {Adhesive composition for automobility}

The present invention relates to an adhesive composition for automobiles, and more particularly, to an automobile adhesive composition having low flow properties, excellent shear strength, impact strength and peel strength, and excellent elongation and water resistance without cracking. will be.

In recent years, the automobile industry is trying to reduce weight through high fuel efficiency engines in order to drastically reduce fuel consumption by vehicle type in accordance with legal regulations. Today's lightweight design of automobiles requires new bonding technologies with the increase of new materials or material mixtures, which allow the use of new materials, bond new materials, and provide structural advantages to bonded components.

The direction of technological development of structural adhesives is to improve the disadvantages of structural adhesives, improve mechanical properties, and one of the most important other things is lowering the price and longer pot life after mixing while curing time after bonding is reduced. It is the development of a short adhesive.

On the other hand, as an adhesive that can be used throughout the automobile and aerospace industries, it should be able to increase the strength of the bonded area by strengthening the bond between mechanical parts and increasing the stiffness of the bond.In addition to having a high breaking elongation, it should also have impact resistance. do.

However, in the case of a conventional adhesive, the strength is relatively low when a stress is applied perpendicularly to the adhesive surface. In other words, it has high strength with respect to the adhesive surface, but it is easy to fall in a direction perpendicular to the adhesive surface. Accordingly, it is urgent to develop an adhesive composition having low flowability, excellent shear strength, impact strength, and peel strength, and no cracking and excellent elongation and water resistance.

KR 10-1991-0015676 A (published on September 30, 1991)

The present invention has been devised to solve the above-described problems, has low flow properties, excellent shear strength, impact strength, and peel strength, and provides an adhesive composition for automobiles having excellent elongation and water resistance without cracking. There is a purpose.

In order to solve the above-described problems, the present invention includes a main resin comprising a first epoxy resin, a second epoxy resin, and a third epoxy resin; A physical property enhancer comprising a polyurethane polyol having a phenol group at the terminal; Desiccant; And a filler, wherein the first epoxy resin, the second epoxy resin, the third epoxy resin, and the physical property enhancer provide an adhesive composition for an automobile satisfying all of the following conditions (1) and (2).

(1) 2 ≤ (ac+b)/d ≤ 38

(2) 0.43 ≤ ab/cd ≤ 18.8

Here, a is the viscosity of the first epoxy resin at 25°C (cps), b is the viscosity of the second epoxy resin at 30°C (cps), and c is the viscosity at 25°C of the third epoxy resin (cps) And d represents the viscosity (cps) of the physical property enhancer at 40°C.

According to an embodiment of the present invention, the first epoxy resin may have a viscosity of 10,000 to 15,000 cps at 25°C, the second epoxy resin may have a viscosity of 65,000 to 150,000 cps at 30°C, and the third The epoxy resin may have a viscosity of 300 to 1000 cps at 25°C.

In addition, the physical property enhancer may have a viscosity of 400,000 to 1,500,000 cps at 40°C.

In addition, the first epoxy resin may be a bisphenol A-type epoxy resin, and the second epoxy resin may be at least one resin selected from a urethane-modified epoxy resin and a CTBN (Carboxyl Terminated Butadiene Acrylonitrile) modified epoxy resin. The 3 epoxy resin may be a dimer acid-modified epoxy resin.

In addition, the main resin may include the first epoxy resin, the second epoxy resin, and the third epoxy resin in a weight ratio of 1: 0.8 to 1.5: 0.05 to 0.3.

In addition, the second epoxy resin may include a urethane-modified epoxy resin and a CTBN-modified epoxy resin in a weight ratio of 1: 0.05 to 0.3.

In addition, 4 to 17 parts by weight of the physical property enhancer may be included based on 100 parts by weight of the main resin.

In addition, 3 to 12 parts by weight of a curing agent and 0.3 to 3 parts by weight of a curing accelerator may be further included based on 100 parts by weight of the main resin.

In addition, 3 to 12 parts by weight of the desiccant containing calcium oxide may be included with respect to 100 parts by weight of the main resin.

In addition, the filler may include two or more types selected from the group consisting of a first filler, a second filler, and a third filler having different shapes.

Further, the first filler may be a needle-shaped filler having an average particle diameter of 7 to 15 μm, the second filler may be a spherical filler having an average particle diameter of 6 to 14 μm, and the third filler has an average particle diameter It may be a plate-shaped filler of 10 to 18㎛.

In addition, the filler may include the first filler, the second filler, and the third filler in a weight ratio of 1: 0.5 to 1.5: 0.5 to 1.5.

In addition, 8 to 18 parts by weight of the filler may be included based on 100 parts by weight of the main resin.

In addition, 0.3 to 3 parts by weight of a strength improving agent and 1.5 to 10 parts by weight of a viscosity modifier may be further included based on 100 parts by weight of the main resin.

The automotive adhesive composition of the present invention has low flow properties, excellent shear strength, impact strength, and peel strength, and does not generate cracks, and has excellent elongation and water resistance.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms, and is not limited to the embodiments described herein.

The adhesive composition for a vehicle according to an embodiment of the present invention includes a main material comprising a first epoxy resin, a second epoxy resin, and a third epoxy resin; Physical property enhancer; Desiccant; And a filler;

Prior to describing each component included in the self-adhesive shipbuilding product according to the present invention, the first epoxy resin, the second epoxy resin, the third epoxy resin and the physical properties provided in the main resin of the automotive adhesive composition of the present invention The reason why the enhancer must satisfy the following conditions (1) and (2) will be described first.

When the viscosity of the automotive adhesive composition is low, there may be a problem in that the flowability is low to the desired level, and the shear strength, impact strength and peel strength cannot exhibit remarkably excellent effects. In addition, when the viscosity of the automotive adhesive composition is high, the occurrence of cracks cannot be prevented to a desired level, elongation may be reduced, and durability may be deteriorated as the buffering effect against external impact is lowered.

Accordingly, the first epoxy resin, the second epoxy resin, and the third epoxy resin, and the physical property enhancers provided in the main resin of the adhesive composition for automobiles of the present invention are the following conditions (1) and conditions ( 2) is satisfied.

As condition (1), 2≦(ac+b)/d≦38, preferably 3.5≦(ac+b)/d≦28, and as condition (2), 0.43≦ab/cd≦18.8 And, preferably, 0.78 ≤ ab/cd ≤ 10.8.

Here, a is the viscosity of the first epoxy resin at 25°C (cps), b is the viscosity of the second epoxy resin at 30°C (cps), and c is the viscosity at 25°C of the third epoxy resin (cps) And d represents the viscosity (cps) of the physical property enhancer at 40°C.

If (ac+b)/d is less than 2 in the above condition (1), uniform mixing may be difficult, so there may be a problem that uniform mechanical properties cannot be displayed, and the desired level of shear strength and peeling There may be a problem that the strength and elongation cannot be expressed, and there may be a problem of increasing the flowability of the final adhesive composition. In addition, when (ac+b)/d exceeds 38, the elongation, peel strength, shear strength, and impact strength may decrease, and there may be a problem in that cracking after curing of the composition cannot be prevented. In addition, if ab/cd is less than 0.43 in the above condition (2), uniform mixing may be difficult, so there may be a problem that uniform mechanical properties cannot be displayed, and the elongation, peel strength and shear strength of the desired level There may be a problem that cannot be expressed, and there may be a problem of increasing the flowability of the final adhesive composition. In addition, if ab/cd exceeds 18.8, elongation, peel strength, shear strength, and impact strength may decrease, and there may be a problem in that cracking after curing of the composition cannot be prevented.

Hereinafter, each component included in the automotive adhesive composition will be described in detail.

First, a main resin including a first epoxy resin, a second epoxy resin, and a third epoxy resin included in the automotive adhesive composition according to the present invention will be described.

The first epoxy resin has a function of improving the shear strength of the automotive adhesive composition, and any epoxy resin that can be used to improve the shear strength commonly in the art can be used without limitation, preferably bisphenol A type It may be an epoxy resin.

In addition, the first epoxy resin may have a viscosity of preferably 10,000 to 15,000 cps at 25° C., and more preferably, a viscosity of 11,500 to 13,500 cps to satisfy the conditions (1) and (2). . If the viscosity of the first epoxy resin is less than 10,000 cps at 25°C, it may be difficult to uniformly mix due to insufficient dispersibility when mixing with calcium carbonate and a curing agent, and there is a problem in that the desired level of shear strength cannot be expressed. If the viscosity exceeds 15,000 cps, there may be difficulties in the workability of the mixing process.Therefore, there may be a problem in that the desired level of shear strength cannot be expressed because the uncured part may remain after curing. have.

In addition, the second epoxy resin has a function of improving the impact strength and elongation of the automotive adhesive composition, and any epoxy resin that can be used to improve the impact strength and elongation generally in the art can be used without limitation, Preferably, it may be at least one selected from a urethane-modified epoxy resin and a CTBN (Carboxyl Terminated Butadiene Acrylonitrile)-modified epoxy resin, and more preferably, a urethane-modified epoxy resin and a CTBN-modified epoxy resin may be mixed and used.

When a urethane-modified epoxy resin and a CTBN-modified epoxy resin are mixed and used as described above, the second epoxy resin is a urethane-modified epoxy resin and a CTBN-modified epoxy resin in a weight ratio of 1: 0.05 to 0.3, preferably 1: 0.1 It may be included in a weight ratio of ~ 0.25. If the weight ratio of the urethane-modified epoxy resin and the CTBN-modified epoxy resin is less than 1:0.05, toughness cannot be imparted to the cured epoxy resin, resulting in lower impact resistance and reduced cohesive failure ratio, and a weight ratio of 1: If it exceeds 0.3, toughness may be imparted, but there may be a problem of deteriorating water resistance due to vulnerability to environmental exposure such as moisture.

In addition, the second epoxy resin may preferably have a viscosity of 65,000 to 150,000 cps at 30° C., and more preferably, a viscosity of 80,000 to 140,000 cps to satisfy the conditions (1) and (2). . If the viscosity of the second epoxy resin at 30° C. is less than 65,000 cps, there may be a problem of increasing the flowability of the final adhesive composition. If the viscosity exceeds 150,000 cps, mixing heat is generated to lower thermal stability, and the final There may be a problem that it reduces the equipment ejection property of the mixture, it is not possible to prevent the occurrence of cracks after curing of the composition, and the elongation may decrease.

In addition, the third epoxy resin has a function of exhibiting a desired level of viscosity by adjusting the viscosity of an automotive adhesive composition, and any epoxy resin that can be used to adjust the viscosity in the art can be used without limitation, Preferably it may be a dimer acid modified epoxy (dimer acid modified epoxy) resin.

In addition, the third epoxy resin may have a viscosity of preferably 300 to 1,000 cps at 25° C., and more preferably, a viscosity of 400 to 900 cps to satisfy the above conditions (1) and (2). . If the viscosity of the third epoxy resin at 25° C. is less than 300 cps or exceeds 1,000 cps, it may affect the ejection property of the equipment, and the peeling strength may be deteriorated due to poor wettability of the adherend.

On the other hand, the main resin is the first epoxy resin, the second epoxy resin and the third epoxy resin in a weight ratio of 1: 0.8 ~ 1.5: 0.05 ~ 0.3, preferably in a weight ratio of 1: 0.9 ~ 1.4: 0.1 ~ 0.25 Can include. If the weight ratio of the first epoxy resin and the second epoxy resin is less than 1:0.8, there may be a problem in that the desired level of impact strength and elongation cannot be expressed, and if the weight ratio exceeds 1:1.5, the desired level There may be a problem that the shear strength cannot be expressed. In addition, if the weight ratio of the first epoxy resin and the third epoxy resin is less than 1:0.05, the occurrence of cracks after curing of the automotive adhesive composition cannot be prevented, the elongation may be lowered, and the weight ratio exceeds 1:0.3. If so, there may be a problem in that the desired level of shear strength cannot be achieved.

Next, a physical property enhancer included in the automotive adhesive composition according to the present invention will be described.

The physical property enhancer performs a function of improving the impact resistance, elongation and adhesion of the automotive adhesive composition, and any physical property enhancer that can be used to improve impact resistance, elongation, and adhesion generally in the art can be used without limitation, Preferably, the use of a polyurethane polyol having a phenol group at the terminal may be more advantageous in remarkably improving impact resistance, elongation, and adhesion when applied to a composition comprising a main resin including an epoxy resin.

The physical property enhancer may have a viscosity of 400,000 to 1,500,000 cps at 40° C. to satisfy the conditions (1) and (2), and preferably may have a viscosity of 440,000 to 1,300,000 cps. If the viscosity of the physical property enhancer at 40°C is less than 400,000 cps, there may be a problem that the shear strength and impact strength decrease, and when the viscosity exceeds 1,500,000 cps, the elongation may decrease, and the workability of the mixing process decreases. Accordingly, there may be a problem in that uniform mechanical properties cannot be displayed.

In addition, the automotive adhesive composition according to the present invention may contain 4 to 17 parts by weight, preferably 7 to 14.5 parts by weight, of the property enhancer based on 100 parts by weight of the main resin. If the physical property enhancer is less than 4 parts by weight per 100 parts by weight of the main resin, a problem may occur that cannot improve the shear strength, impact strength, and adhesion to the desired level, and if it exceeds 17 parts by weight, the water resistance is deteriorated. Can occur.

Next, the curing agent contained in the automotive adhesive composition according to the present invention will be described.

The curing agent may be used without limitation as long as it is a curing agent conventionally used to cure an epoxy resin in the art, and may be preferably dicyandiamide.

There is no limitation on the properties of the curing agent, and for example, the curing agent may be solid or liquid. When the properties of the curing agent are solid, the curing agent may have an average particle diameter of 45 μm or less, preferably an average particle diameter of 40 μm or less, but is not limited thereto.

In addition, the automotive adhesive composition according to the present invention may include 3 to 12 parts by weight of the curing agent, preferably 4 to 10 parts by weight, based on 100 parts by weight of the main resin. If the curing agent is less than 3 parts by weight with respect to 100 parts by weight of the main resin, the flowability increases, and as the automotive adhesive composition is not cured to the desired level, shear strength, impact strength, and peel strength may decrease. If exceeds 12 parts by weight, cracks may occur, and a problem of lowering the elongation may occur.

In addition, the automotive adhesive composition according to the present invention may further include a curing accelerator.

The curing accelerator may be used without limitation as long as it is a material commonly used as a curing accelerator in the art, and may be preferably phenyl dimethyl urea. In addition, the properties of the curing accelerator are not limited, and for example, the curing accelerator may be in a solid state or a liquid state, and preferably, the curing accelerator may be in a solid state.

The curing accelerator may be further included in an amount of 0.3 to 3 parts by weight, preferably 0.5 to 2.5 parts by weight, based on 100 parts by weight of the main resin. If the curing accelerator is less than 0.3 parts by weight with respect to 100 parts by weight of the main resin, it may not be cured to the desired level and there may be a problem in expressing the desired strength, and if it exceeds 3 parts by weight, a problem of deteriorating storage may occur. .

Next, the desiccant contained in the automotive adhesive composition of the present invention will be described. The hygroscopic agent may be used without limitation, as long as it is a material that can be used to absorb moisture in the art, preferably calcium oxide.

The desiccant may be included in an amount of 3 to 12 parts by weight, and preferably 4 to 10 parts by weight, based on 100 parts by weight of the main resin. If the desiccant is less than 3 parts by weight based on 100 parts by weight of the main resin, there may be a problem that the desired level of water resistance cannot be expressed, and if it exceeds 12 parts by weight, the viscosity increases, which adversely affects the ejection property of the final mixture. According to this, there may be a problem in workability, and shear strength and elongation may be lowered.

Next, a filler included in the automotive adhesive composition according to the present invention will be described.

The filler may include two or more selected from the group consisting of a first filler, a second filler, and a third filler having different shapes, and preferably, a first filler, a second filler, and a third filler having different shapes. It can be equipped with all.

The first filler has a function of controlling viscosity and specific gravity, and any filler having a shape that can be used to control viscosity and specific gravity in the art can be used without limitation. Preferably, the first filler is a needle-shaped filler. It can be a mold filler.

In addition, the first filler may have an average particle diameter of 7 to 15 μm, preferably an average particle diameter of 8 to 14 μm. If the average particle diameter of the first filler is less than 7 μm, the viscosity increases and there may be problems in ejection of the equipment, water resistance and impact strength may decrease. If the average particle diameter exceeds 15 μm, the viscosity decreases and flowability There may be a problem.

The second filler functions to control viscosity and specific gravity, and any filler having a shape that can be used to control viscosity and specific gravity in the art can be used without limitation, and preferably, the second filler is conceived. It can be a mold filler.

In addition, the second filler may have an average particle diameter of 6 to 14 μm, preferably an average particle diameter of 7 to 13 μm. If the average particle diameter of the second filler is less than 6 ㎛, there may be a problem of decreasing the impact strength because brittleness increases and becomes hard. If the average particle diameter exceeds 14 ㎛, the brittleness decreases and becomes flexible. There may be a problem that decreases.

The third filler has a function of improving the peeling strength, and any filler having a shape that can be used to improve the peeling strength generally in the art can be used without limitation, and preferably the third filler is a plate-shaped filler. I can.

In addition, the third filler may have an average particle diameter of 10 to 18 μm, preferably an average particle diameter of 11 to 17 μm. If the average particle diameter of the third filler is less than 10 μm, there may be a problem that the peeling state is poor during the T-peel test, and if the average particle diameter exceeds 18 μm, there may be a problem of reducing the impact strength.

The first filler, the second filler, and the third filler may be used without limitation as long as they are commonly used in the art to control viscosity and specific gravity and improve peel strength, and preferably the first filler, the second filler The filler and the third filler may be calcium carbonate.

Meanwhile, the filler comprises the first filler, the second filler, and the third filler in a weight ratio of 1: 0.5 to 1.5: 0.5 to 1.5, preferably the first filler, the second filler, and the third filler by 1: 0.7 ~ 1.4: It can be included in a weight ratio of 0.7 ~ 1.4. If the weight ratio of the first filler and the second filler is out of the above range, there may be a problem in that the desired level of viscosity and specific gravity of the automotive adhesive composition cannot be adjusted. In addition, if the weight ratio of the first filler and the third filler is less than 1:0.5, the improvement in peel strength may be insignificant, and if the weight ratio exceeds 1:1.5, the viscosity and specific gravity of the automotive adhesive composition can be adjusted to a desired level. There may be problems that cannot be done.

In addition, the automotive adhesive composition of the present invention may include 8 to 18 parts by weight of the filler, preferably 10 to 16 parts by weight, based on 100 parts by weight of the main resin to be described later. If the filler is less than 8 parts by weight based on 100 parts by weight of the main resin, the adhesive composition for automobiles cannot exhibit the desired appropriate viscosity and specific gravity, and the peel strength may be lowered. If the filler exceeds 18 parts by weight, the viscosity and As the specific gravity becomes excessive, the problem of overall strength reduction such as shear strength and impact strength may occur.

On the other hand, the automotive adhesive composition according to the present invention may further include a strength improving agent to improve the peel strength.

The strength improving agent may be used without limitation as long as it is a strength improving agent commonly used in the art, and preferably, it is easier to improve peel strength by using an epoxy silane.

The strength improving agent may be further included in an amount of 0.3 to 3 parts by weight, preferably 0.5 to 2.5 parts by weight, based on 100 parts by weight of the main resin. If the strength improving agent is less than 0.3 parts by weight with respect to 100 parts by weight of the main resin, the degree of improvement in peel strength may be insignificant, and if it exceeds 3 parts by weight, there may be a problem that the adhesive strength decreases due to the effect of the unreacted product in the composite.

In addition, the adhesive composition for automobiles according to the present invention may further include a viscosity modifier in order to improve viscosity and reduce flowability so that the composition does not flow.

The viscosity modifier may be used without limitation as long as it can improve viscosity and lower flowability in the art, and preferably fumed silica may be used.

There are no restrictions on the properties and shapes of the viscosity modifier, and for example, the viscosity modifier may be solid. When the viscosity modifier is a solid state, the viscosity modifier may have an average particle diameter of 0.1 to 0.5 μm, preferably 0.2 to 0.4 μm, but is not limited thereto.

The viscosity modifier may be further included in an amount of 1.5 to 10 parts by weight, preferably 3 to 9 parts by weight, based on 100 parts by weight of the main resin. If the viscosity modifier is less than 1.5 parts by weight based on 100 parts by weight of the main resin, a problem of increasing flowability may occur. If it exceeds 10 parts by weight, the viscosity of the adhesive composition becomes very high, resulting in poor workability, and the elongation after curing is reduced. There may be a problem of deterioration.

The automotive adhesive composition of the present invention has low flow properties, excellent shear strength, impact strength, and peel strength, and does not generate cracks, and has excellent elongation and water resistance.

The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, which should be interpreted to aid understanding of the present invention.

<Example 1>

A bisphenol A-type epoxy resin having a viscosity of 12,500 cps at 25°C as the first epoxy resin, a urethane-modified epoxy resin and CTBN-modified epoxy resin having a viscosity of 110,000 cps each at 30°C as a second epoxy resin, and a third epoxy resin. A main resin was prepared by uniformly mixing a dimer acid-modified epoxy resin having a viscosity of 650 cps at 25° C. using a stirrer, a mixing equipment, at a weight ratio of 1: 1.15: 0.15. At this time, the weight ratio of the urethane-modified epoxy resin and the CTBN-modified epoxy resin was 1:0.15. To the prepared base resin, 7 parts by weight of a polyurethane polyol (DY-965, Huntsman Advanced Materials) having a phenol group at the end having a viscosity of 870,000 cps at 40°C as a physical property enhancer per 100 parts by weight of the base resin was oxidized with a desiccant 7 parts by weight of calcium, 4 parts by weight of acicular calcium carbonate filler with an average particle diameter of 11 µm as a first filler, 4 parts by weight of spherical calcium carbonate filler with an average particle diameter of 10 µm as a second filler, and an average particle diameter of the third filler After adding 4 parts by weight of a 14 µm plate-shaped calcium carbonate filler, 1.5 parts by weight of epoxy silane as a strength improving agent, and 6 parts by weight of fumed silica having an average particle diameter of 0.3 µm as a viscosity enhancing agent, a stirrer was added again. And mixed. Store the mixed composition in a low-temperature chamber (-10℃) to lower the temperature, and add 6 parts by weight of dicyandiamide with an average particle diameter of 20 μm as a curing agent to 100 parts by weight of the main resin in the lowered composition, and a curing accelerator. 1.5 parts by weight of low phenyl dimethyl urea was added and mixed using a stirrer, and then the mixed composition was removed by using a paste mixer to remove microbubbles in the sample to prepare an automotive adhesive composition. .

<Examples 2 to 25 and Comparative Examples 1 to 5>

Prepared by carrying out the same manner as in Example 1, but the viscosity of each of the first epoxy resin, the second epoxy resin, the third epoxy resin, the physical property enhancer, the weight ratio of the first epoxy resin and the second epoxy resin, the content of the property enhancer, and the filler By changing the content, etc. to prepare an adhesive composition for automobiles as shown in Tables 1 to 5.

<Experimental Example 1: Characteristics before curing of an automotive adhesive composition>

In order to evaluate the properties before curing of the adhesive compositions for automobiles prepared in Examples and Comparative Examples, the following physical properties were evaluated and shown in Tables 1 to 5.

1. Viscosity evaluation

200 ml of each of the adhesive compositions for automobiles according to the Examples and Comparative Examples were put in a container and left in a chamber so that the temperature of the sample was 20±1° C., and the sample was stirred and mixed so that the temperature of the sample was kept uniform and no air bubbles entered. Thereafter, the spindle NO.7 of the viscometer (DV-I PRIME, BROOKFIELD, U.S.A.) was placed in the center of the sample container and then dipped to the immersion mark of the spindle. At this time, the number of rotations of the spindle was set to 2 RPM, rotated for 1 minute and 30 seconds, and then the measured value was recorded.

2. Specific gravity measurement

First, the weight of the specific gravity cup (1127399, BYK, GERMANY) is measured using a scale (AJ-4200E-C, SHINKO DENSHI, JAPAN), and the vehicle according to the Example and Comparative Example maintaining a temperature of 20±1℃ Each 100 ml of the adhesive composition was filled into the specific gravity cup, taking care not to enter air bubbles, and the lid was closed. Then, after wiping until the sample does not come out from the hole located in the center of the lid, the specific gravity cup was placed on the scale to measure the weight, and the specific gravity was calculated according to Equation 1 below.

[Equation 1]

3. Flowability measurement

Each of the automotive adhesive compositions according to Examples and Comparative Examples was applied to a steel plate having a thickness of 0.8 mm and a width of 75 × 150 mm in an inverted'a' shape of a thickness of 3 mm and a width of 50 × 100 mm, and flowability was measured. For this purpose, each test piece was fixed at an angle of 70° to measure the flow after 30 minutes at room temperature. And when the flowability was good at room temperature, the flowability of the cured adhesive composition was measured after standing at 180°C for 28 minutes using a hot air oven (OVEN, ESPEC, JAPAN) in the same way.

<Experimental Example 2: Characteristics after curing of the adhesive composition for automobiles>

In order to evaluate the properties after curing of the automotive adhesive compositions prepared in Examples and Comparative Examples, the following physical properties were evaluated and are shown in Tables 1 to 5.

1. Shear strength measurement

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples on a steel plate having a thickness of 0.8 mm and a width of 25 × 150 mm was made into a thickness of 0.2 mm and a width of 25 × 12.5 mm, but the thickness using a glass bead. Then, after fixing the joint with a clip, it was cured at 180° C. for 28 minutes using a hot air oven and left at room temperature for 1 hour. And, the shear strength was measured by applying a tensile load in the direction of 180° at a speed of 5 mm/min in a universal test machine (ZWICK-Z50, GERMANY).

2. Water resistance (shear) measurement

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples on a steel plate having a thickness of 0.8 mm and a width of 25 × 150 mm was made into a thickness of 0.2 mm and a width of 25 × 12.5 mm, but the thickness using a glass bead. Then, after fixing the joint with a clip, it was cured at 180° C. for 28 minutes using a hot air oven and left at room temperature for 1 hour. And, after exposing it to water at 40℃ for 168 hours, let it stand at room temperature for 30 minutes, and apply a tensile load in the direction of 180° at a speed of 5mm/min in a universal test machine (ZWICK-Z50, GERMANY). Water resistance (shear) was measured.

3. T peel strength measurement

Each of the adhesive composition for automobiles according to Examples and Comparative Examples on two steel plates having a thickness of 0.8 mm and a width of 25 × 150 mm is a thickness of 0.2 mm and a length of 25 × 100 mm, but a glass bead is used. After adjusting the thickness and fixing the joint with a clip, it was cured at 180°C for 28 minutes using a hot air oven and left at room temperature for 1 hour. Then, spread the joint part without the hardened material at 180° and fix each to the clamp part of the universal test machine (ZWICK-Z50, GERMANY), and fix the tensile load in the direction of 180° at a speed of 50 mm/min. Added. At this time, the T peel strength value was obtained from the load-displacement curve of the tensile tester.

4. Impact strength measurement

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples on two bent specimens having a thickness of 1.6 mm and width × length 20 × 90 mm is 0.2 mm thick and 20 × 30 mm horizontally × vertically, and a glass bead After adjusting the thickness by using, and fixing the joint with a clip, it was cured at 180°C for 28 minutes using a hot air oven and left at room temperature for 1 hour. And each specimen was subjected to impact under conditions of 45 kg in weight, 0.2 m in height, and 2 m/s in speed using an impact tester (CEAST9350, INSTRON, U.S.A.). At this time, the impact strength value was recorded as the impact strength value at the point at which the peak is 25% from the start point (start point) and the point at which the end point becomes 10%.

5. Fracture Mode Cohesive Failure (CF) Rate Measurement

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples on a steel plate having a thickness of 0.8 mm and a width of 25 × 150 mm was made into a thickness of 0.2 mm and a width of 25 × 12.5 mm, but the thickness using a glass bead. Then, after fixing the joint with a clip, it was cured at 180° C. for 28 minutes using a hot air oven and left at room temperature for 1 hour. And, the shear strength was measured by applying a tensile load in the direction of 180° at a speed of 5 mm/min in a universal test machine (ZWICK-Z50, GERMANY). In addition, there are three types of interfacial failure (Adhesion Failure, AF or Interfacial Failure, IF) between the adhesive and the adherend, Cohesive Failure (CF) in which the adhesive itself is destroyed, and Substrate Failure (SF). The proportion of cohesive failure (CF) in the failure mode was measured.

6. Elongation measurement

Applying each of the adhesive compositions for automobiles according to Examples and Comparative Examples on a dumbbell-shaped tensile specimen frame having a thickness of 3 mm and 20 × 160 mm in width and height to which the release agent is sufficiently applied, and curing at 180° C. for 28 minutes using a hot air oven After that, it was left at room temperature for 1 hour. In addition, each tensile specimen was separated and the gage distance of the specimen was marked according to the standard and fixed to the clamp portion of the universal test machine (ZWICK-Z50, GERMANY) of the specimen. Thereafter, a load was applied at a tensile speed of 50 mm/min, and the elongation at break was measured.

7. Elongation uniformity evaluation

For each specimen prepared through the automotive adhesive composition according to Examples and Comparative Examples, 10 specimens were prepared for each specimen, and the elongation was measured by the elongation measuring method. In addition, the uniformity of the elongation was evaluated according to Equation 2 below through the average elongation of each of the 10 specimens according to Examples and Comparative Examples and the elongation of the specimen having the largest difference in the average elongation and elongation. At this time, a small uniformity value indicates that the composition has been prepared to have uniform mechanical properties, and a large uniformity value indicates that the composition has been prepared to have non-uniform mechanical properties.

[Equation 2]

division Example
One Example
2 Example
3 Example
4 Example
5 Example
6 First epoch
Sisuji Viscosity
(cps, 25℃) 12,500 8,000 11,500 13,500 18,000 12,000 Second epoch
Sisuji Viscosity
(cps, 30℃) 110,000 110,000 110,000 110,000 110,000 50,000 3rd epoch
Sisuji Viscosity
(cps, 25℃) 650 650 650 650 650 850 Properties
Enhancer Viscosity
(cps, 40℃) 870,000 870,000 870,000 870,000 870,000 1,200,000 content 7 7 7 7 7 7 Condition(1) (ac+b)/d 9.47 6.1 8.72 10.21 13.58 8.54 Condition(2) ab/cd 2.43 1.56 2.24 2.63 3.5 0.59 1st, 2nd epoxy
Resin weight ratio 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 Filler content (parts by weight) 12 12 12 12 12 12 Properties before curing Viscosity
(Ps,20℃) 16,000 15,600 15,850 16,150 16,500 14,100 importance 1.2 1.2 1.2 1.2 1.2 1.1 Flowability (mm) 2.5 2.5 2.5 2.5 2.5 2.8 Properties after curing Shear strength (Mpa) 24.5 17.5 23.4 23.4 16.5 22.5 Water resistance
(Shear, Mpa) 24 17 23 23 16 22 T peeling strength (N/25mm) 260 220 260 260 244 248 Impact strength (N/mm) 33 32 33 33 21 22 Breakdown mode (%, CF) 90 97 90 90 88 89 Elongation(%) 9.1 8.9 9.1 9.1 5.3 5.4 Elongation uniformity (%) 0.7 2.4 0.9 0.9 1.3 1.2

division Example
7 Example
8 Example
9 Example
10 Example
11 Example
12 First epoch
Sisuji Viscosity
(cps, 25℃) 12,000 12,500 12,500 13,000 12,000 13,000 Second epoch
Sisuji Viscosity
(cps, 30℃) 80,000 140,000 170,000 110,000 85,000 135,000 3rd epoch
Sisuji Viscosity
(cps, 25℃) 850 650 650 150 400 900 Properties
Enhancer Viscosity
(cps, 40℃) 1,250,000 870,000 870,000 750,000 1,250,000 490,000 content 7 7 7 7 7 7 Condition(1) (ac+b)/d 8.22 9.5 9.53 2.75 3.91 24.15 Condition(2) ab/cd 0.9 3.1 3.76 12.71 2.04 3.98 1st, 2nd epoxy
Resin weight ratio 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 Filler content (parts by weight) 12 12 12 12 12 12 Properties before curing Viscosity
(Ps,20℃) 15,000 17,000 18,000 15,750 15,900 16,100 importance 1.1 1.2 1.2 1.2 1.2 1.2 Flowability (mm) 2.6 2.5 2.4 2.5 2.5 2.5 Properties after curing Shear strength (Mpa) 24.5 24.5 23.5 24.5 24.5 24.5 Water resistance
(Shear, Mpa) 24 24 23 19 23 24 T peeling strength (N/25mm) 255 260 260 198 252 253 Impact strength (N/mm) 33 33 30 33 33 33 Breakdown mode (%, CF) 90 89 79 90 90 90 Elongation(%) 9.1 9 7.2 9.1 9.1 9.1 Elongation uniformity (%) 1.1 1.6 2.1 0.7 0.8 0.7

division Example
13 Example
14 Example
15 Example
16 Example
17 Example
18 First epoch
Sisuji Viscosity
(cps, 25℃) 12,500 13,000 13,000 12,500 12,500 12,500 Second epoxy resin Viscosity
(cps, 30℃) 110,000 120,000 135,000 110,000 110,000 110,000 3rd epoch
Sisuji Viscosity
(cps, 25℃) 1,200 800 450 650 650 650 Properties
Enhancer Viscosity
(cps, 40℃) 870,000 300,000 440,000 1,300,000 1,800,000 870,000 content 7 7 7 7 7 2 Condition(1) (ac+b)/d 17.37 35.07 13.6 6.34 4.58 9.47 Condition(2) ab/cd 1.32 6.5 8.86 1.63 1.18 2.43 1st, 2nd epoxy
Resin weight ratio 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 Filler content (parts by weight) 12 12 12 12 12 12 Properties before curing Viscosity
(Ps,20℃) 16,300 11,950 14,900 19,600 23,500 13,350 importance 1.2 1.1 1.2 1.2 1.2 1.2 Flowability (mm) 2.7 3.7 2.8 2.3 2.0 2.5 Properties after curing Shear strength (Mpa) 21 18.9 23.5 24.2 24.2 23 Water resistance
(Shear, Mpa) 18 18.5 23 23.8 23.9 22 T peeling strength (N/25mm) 191 260 259 260 260 263.5 Impact strength (N/mm) 30 21 32 33 33 31 Breakdown mode (%, CF) 88 90 90 90 90 90 Elongation(%) 7.6 9.0 9.1 8.8 6.8 6 Elongation uniformity (%) 0.9 0.7 0.7 0.9 4.2 0.9

division Example
19 Example
20 Example
21 Example
22 Example
23 Example
24 First epoch
Sisuji Viscosity
(cps, 25℃) 12,500 12,500 12,500 12,500 12,500 12,500 Second epoxy resin Viscosity
(cps, 30℃) 110,000 110,000 110,000 110,000 110,000 110,000 3rd epoxy resin Viscosity
(cps, 25℃) 650 650 650 650 650 650 Properties
Enhancer Viscosity
(cps, 40℃) 870,000 870,000 870,000 870,000 870,000 870,000 content 11 14.5 20 7 7 7 Condition(1) (ac+b)/d 9.47 9.47 9.47 9.47 9.47 9.47 Condition(2) ab/cd 2.43 2.43 2.43 2.43 2.43 2.43 1st, 2nd epoxy
Resin weight ratio 1:1.15 1:1.15 1:1.15 1:0.5 1:1.8 1:1.15 Filler content (parts by weight) 12 12 12 12 12 5 Properties before curing Viscosity
(Ps,20℃) 16,900 24,100 33,200 14,100 18,200 15,000 importance 1.2 1.2 1.2 1.2 1.2 1.2 Flowability (mm) 2.5 2.5 4 3.2 2.8 2.5 Properties after curing Shear strength (Mpa) 25.3 24.5 21.4 24.5 16.7 17 Water resistance
(Shear, Mpa) 25.5 24 18.1 24 16.5 17 T peeling strength (N/25mm) 257.5 255 221 256 257 184 Impact strength (N/mm) 34 34 27 23 31 26 Breakdown mode (%, CF) 90 90 70 90 90 79 Elongation(%) 10.6 10.7 11 5.2 8.5 9 Elongation uniformity (%) 0.8 0.7 0.7 0.8 1.1 1.2

division Example
25 Comparative example
One Comparative example
2 Comparative example
3 Comparative example
4 Comparative example
5 First epoch
Sisuji Viscosity
(cps, 25℃) 12,500 12,500 8,500 16,500 9,000 16,500 Second epoxy resin Viscosity
(cps, 30℃) 110,000 110,000 55,000 160,000 55,000 160,000 3rd epoxy resin Viscosity
(cps, 25℃) 650 650 250 900 1,100 350 Properties
Enhancer Viscosity
(cps, 40℃) 870,000 - 1,600,000 350,000 1,600,000 350,000 content 7 - 7 7 7 7 Condition(1) (ac+b)/d 9.47 - 1.36 42.89 6.22 16.96 Condition(2) ab/cd 2.43 - 1.17 8.38 0.28 21.55 1st, 2nd epoxy
Resin weight ratio 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 Filler content (parts by weight) 20 12 12 12 12 12 Properties before curing Viscosity
(Ps,20℃) 18,000 15,000 13,250 16,800 13,350 16,750 importance 1.2 1.2 1.2 1.2 1.2 1.2 Flowability (mm) 2.5 2.5 3.1 2.5 3.1 2.5 Properties after curing Shear strength (Mpa) 17 21 19.5 19.6 19.7 19.5 Water resistance
(Shear, Mpa) 17 21 18.5 19 18.6 18.8 T peeling strength (N/25mm) 232 250 182 188 183 186 Impact strength (N/mm) 26 30 31 23 31 23 Breakdown mode (%, CF) 80 90 90 72 90 73 Elongation(%) 9 5.1 6.0 6.2 6.1 6.2 Elongation uniformity (%) 0.8 0.6 4.4 0.9 4.4 1.0

As can be seen from Tables 1 to 5,

Satisfying all the viscosity of each of the first epoxy resin, the second epoxy resin, the third epoxy resin, and the physical property enhancer according to the present invention, the weight ratio of the first epoxy resin and the second epoxy resin, the content of the property enhancer, and the content of the filler. Examples 1, 3, 4, 7, 8, 11, 12, 15, 16, 19, and 20 are omitted; Examples 2, 5, 6, 9, 10, 13, 14, 17, 18 , Compared to 21 to 25 and Comparative Examples 1 to 5, the composition did not flow, the composition did not flow, the rate of cohesive failure was high, the shear strength, water resistance, T peeling strength, impact strength and elongation were excellent, and uniform elongation was achieved. It was confirmed that the effect shown could be achieved.

Although an embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in the present specification, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same idea. It will be possible to easily propose other embodiments by changing, deleting, adding, etc., but it will be said that this is also within the scope of the present invention.

Claims (14)

A main resin comprising a first epoxy resin, a second epoxy resin, and a third epoxy resin;
A physical property enhancer comprising a polyurethane polyol having a phenol group at the terminal;
Desiccant; And
Including, the first epoxy resin, the second epoxy resin, the third epoxy resin, and the physical property enhancer satisfy all of the following conditions (1) and (2),
The second epoxy resin has a viscosity of 80,000 to 140,000 cps at 30°C for an automotive adhesive composition:
(1) 3.5 ≤ (ac+b)/d ≤ 28
(2) 0.78 ≤ ab/cd ≤ 10.8
In this case, a is the viscosity of the first epoxy resin at 25°C (cps), b is the viscosity at 30°C of the second epoxy resin (cps), and c is the viscosity at 25°C of the third epoxy resin (cps) And d represents the viscosity (cps) at 40°C of the physical property enhancer. The method of claim 1,
The first epoxy resin has a viscosity of 10,000 to 15,000 cps at 25°C,
The third epoxy resin has a viscosity of 300 ~ 1000 cps at 25 ℃ automotive adhesive composition. The method of claim 1,
The physical property enhancer has a viscosity of 400,000 to 1,500,000 cps at 40°C for an automotive adhesive composition. The method of claim 1,
The first epoxy resin is a bisphenol A type epoxy resin,
The second epoxy resin is at least one resin selected from a urethane-modified epoxy resin and a CTBN (Carboxyl Terminated Butadiene Acrylonitrile) modified epoxy resin,
The third epoxy resin is a dimer acid-modified epoxy resin for automobile adhesive composition. The method of claim 1, wherein the main resin is
An automotive adhesive composition comprising the first epoxy resin, the second epoxy resin, and the third epoxy resin in a weight ratio of 1: 0.8 to 1.5: 0.05 to 0.3. The method of claim 1,
The second epoxy resin comprises a urethane-modified epoxy resin and a CTBN-modified epoxy resin in a weight ratio of 1: 0.05 to 0.3. The method of claim 1,
An automotive adhesive composition comprising 4 to 17 parts by weight of the physical property enhancer based on 100 parts by weight of the main resin. The method of claim 1,
An automotive adhesive composition further comprising 3 to 12 parts by weight of a curing agent and 0.3 to 3 parts by weight of a curing accelerator based on 100 parts by weight of the main resin. The method of claim 1,
An automotive adhesive composition comprising 3 to 12 parts by weight of the desiccant containing calcium oxide based on 100 parts by weight of the main resin. The method of claim 1,
The filler is a vehicle adhesive composition comprising two or more selected from the group consisting of a first filler, a second filler, and a third filler having different shapes. The method of claim 10,
The first filler is a needle-shaped filler having an average particle diameter of 7 ~ 15㎛,
The second filler is a spherical filler having an average particle diameter of 6 ~ 14㎛,
The third filler is a plate-shaped filler having an average particle diameter of 10 ~ 18㎛ for automobile adhesive composition. The method of claim 10,
The filler is an automotive adhesive composition comprising the first filler, the second filler and the third filler in a weight ratio of 1: 0.5 to 1.5: 0.5 to 1.5. The method of claim 1,
An automotive adhesive composition comprising 8 to 18 parts by weight of the filler based on 100 parts by weight of the main resin. The method of claim 1,
An automotive adhesive composition further comprising 0.3 to 3 parts by weight of a strength improving agent and 1.5 to 10 parts by weight of a viscosity modifier based on 100 parts by weight of the main resin.