KR102197041B1 - Foam-type adhesive composition for automobility - Google Patents

Abstract

The present invention relates to a foam-type adhesive composition for automobiles, and more particularly, a foam-type adhesive composition for automobiles that has a large foaming rate, excellent shear strength, impact strength and flexural strength, and does not generate cracks and has excellent water resistance. It is about.

Description

Foam-type adhesive composition for automobility

The present invention relates to a foam-type adhesive composition for automobiles, and more particularly, a foam-type adhesive composition for automobiles that has a large foaming rate, excellent shear strength, impact strength and flexural strength, and does not generate cracks and has excellent water resistance. It is about.

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 the conventional adhesive, the foaming rate was high and it was not possible to exhibit excellent impact strength. Accordingly, it is urgent to develop an adhesive composition having high foaming rate, excellent shear strength, impact strength and flexural strength, and excellent water resistance at the same time without cracking.

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

The present invention has been devised to solve the above-described problems, and has a large foaming rate, excellent shear strength, impact strength, and flexural strength, and provides a foam adhesive composition for automobiles that does not generate cracks and has excellent water resistance. There is a purpose.

In order to solve the above-described problem, the present invention includes a primary resin comprising a first epoxy resin, a second epoxy resin, a third epoxy resin, and a fourth epoxy resin; blowing agent; Desiccant; And a filler, wherein the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin satisfy all of the following conditions (1) and (2). do.

(1) (a+c+d)/b ≥ 0.23

(2) ad/bc ≥ 1.6.

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 fourth epoxy resin at 75°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 Epoxy resin may have a viscosity of 300 to 1000 cps at 25°C, and the fourth epoxy resin may have a viscosity of 25,000 to 65,000 cps at 75°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, and the fourth epoxy resin may be a CTBN rubber modified epoxy resin.

In addition, the main resin may include the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin in a weight ratio of 1: 0.8 to 1.5: 0.05 to 0.3: 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, 2 to 11 parts by weight of a curing agent and 0.2 to 2.5 parts by weight of a curing accelerator may be further included based on 100 parts by weight of the main resin.

In addition, 0.5 to 3.5 parts by weight of the foaming agent may be included based on 100 parts by weight of the main resin.

In addition, 3 to 11 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, 3 to 13 parts by weight of the filler may be included based on 100 parts by weight of the main resin.

In addition, 0.2 to 2.5 parts by weight of a physical property enhancer and 2 to 10 parts by weight of a viscosity modifier may be further included based on 100 parts by weight of the main resin.

The foamed adhesive composition for automobiles of the present invention has a high foaming rate, excellent shear strength, impact strength, and flexural strength, and does not generate cracks and has excellent 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.

A foam-type adhesive composition for a vehicle according to an embodiment of the present invention includes a main resin including a first epoxy resin, a second epoxy resin, a third epoxy resin, and a fourth epoxy resin; blowing agent; Desiccant; And a filler;

Prior to describing each component included in the foam adhesive composition for automobiles according to the present invention, the first epoxy resin, the second epoxy resin, and the third epoxy resin provided in the main resin of the foam adhesive composition for automobiles of the present invention And the reason why the fourth epoxy resin must satisfy the following conditions (1) and (2) will be described first.

When the viscosity of the foamed adhesive composition for automobiles is low, there may be a problem in that the shear strength, impact strength, and flexural strength at a desired level cannot exhibit remarkably excellent effects. In addition, when the viscosity of the foamed adhesive composition for automobiles is high, the occurrence of cracks cannot be prevented to a desired level, the buffering effect against external impact may be reduced, and the foaming rate may be low.

Accordingly, the first epoxy resin, the second epoxy resin, the third epoxy resin and the fourth epoxy resin provided in the main resin of the foam adhesive composition for automobiles of the present invention are the following conditions (1) And condition (2) are all satisfied.

As condition (1), (a+c+d)/b ≥ 0.23, preferably 0.29 ≤ (a+c+d)/b ≤ 0.95, and as condition (2), ad/bc ≥ 1.6 And, preferably, 2.5 ≤ ad/bc ≤ 26.

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 fourth epoxy resin at 75°C.

If (a+c+d)/b in the above condition (1) is less than 0.23, there may be a problem that the desired level of flexural strength, shear strength, and impact strength cannot be expressed, and cracking can be prevented. It may not be. In addition, if ad/bc is less than 1.6 in the above condition (2), there may be a problem in that the desired level of flexural strength, shear strength, and impact strength cannot be expressed, and there may be a problem in that the occurrence of cracks cannot be prevented. have.

Hereinafter, each configuration included in the foamed adhesive composition for an automobile will be described in detail.

First, a main resin comprising a first epoxy resin, a second epoxy resin, a third epoxy resin, and a fourth epoxy resin included in the foamed adhesive composition for an automobile according to the present invention will be described.

The first epoxy resin has a function of improving the shear strength of the foamed adhesive composition for automobiles, and any epoxy resin that can be used to improve the shear strength commonly in the art can be used without limitation, preferably bisphenol It may be a type A 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 functions to improve the impact strength of the foamed adhesive composition for automobiles, and any epoxy resin that can be used to improve the impact strength commonly in the art may be used without limitation, and preferably 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 is less than 65,000 cps at 30°C, the impact strength may be lowered, and if the viscosity exceeds 150,000 cps, heat of mixing is generated to lower thermal stability and reduce the equipment ejection property of the final mixture. And, there may be a problem that cannot prevent the occurrence of cracks after curing the composition.

In addition, the third epoxy resin functions to exhibit a desired level of viscosity by controlling the viscosity of the foamed adhesive composition for automobiles, and any epoxy resin that can be used to adjust the viscosity in the art can be used without limitation. And, 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 affects the ejection property of the equipment and is not good for wettability of the adherend, so that shear strength, flexural strength and impact strength may decrease.

In addition, the fourth epoxy resin performs a function of improving the impact strength and flexural strength of the foamed adhesive composition for automobiles, and any epoxy resin that can be used to improve impact strength and flexural strength in the art is not limited. It can be used, preferably a CTBN rubber-modified epoxy resin.

In addition, the fourth epoxy resin may have a viscosity of 25,000 to 65,000 cps at 75° C. to satisfy the conditions (1) and (2), and preferably, the viscosity may be 30,000 to 60,000 cps. If the viscosity of the fourth epoxy resin at 75° C. is less than 30,000 cps or exceeds 60,000 cps, the impact strength and flexural strength may decrease.

On the other hand, the main resin is the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin in a weight ratio of 1: 0.8 to 1.5: 0.05 to 0.3: 0.05 to 0.3, preferably 1: 0.9 to It may be included in a weight ratio of 1.4: 0.1 to 0.25: 0.1 to 0.25.

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 that the desired level of impact strength cannot be expressed, and if the weight ratio exceeds 1:1.5, the desired level of shear strength There may be a problem that 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, cracks cannot be prevented after curing of the foamed adhesive composition for automobiles, and if the weight ratio exceeds 1:0.3, the desired level There may be a problem that the shear strength cannot be expressed. And, if the weight ratio of the first epoxy resin and the fourth epoxy resin is less than 1:0.05, there may be a problem in that the desired level of impact strength and flexural strength cannot be expressed, and if the weight ratio exceeds 1:0.3, the target There may be a problem in that it is not possible to develop the level of shear strength.

Next, a curing agent and a curing catalyst that may be further included in the foamed adhesive composition for an automobile 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.

The foamed adhesive composition for a vehicle according to the present invention may contain 2 to 11 parts by weight of a curing agent, preferably 3 to 10 parts by weight, based on 100 parts by weight of the main resin. If the curing agent is less than 2 parts by weight based on 100 parts by weight of the main resin, the flowability increases, and the shear strength, impact strength, and flexural strength may decrease as the foamed adhesive composition for automobiles is not cured to the desired level. If the curing agent exceeds 11 parts by weight, cracks may occur.

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 0.2 to 2.5 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the main resin. If the curing accelerator is less than 0.2 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 2.5 parts by weight, a problem of deteriorating storage may occur .

Next, a foaming agent contained in the foam adhesive composition for an automobile according to the present invention will be described.

The foaming agent performs the function of improving the foaming rate of the foamed adhesive composition for automobiles, and can be used without limitation, as long as it is a foaming agent commonly used in the art, preferably azodicarbonamide, p- TSH (p-toluenesulfonyl hydrazide), expandable blowing agent (Microcapsule or Microsphere), DPT (N,N`-Dinitroso pentamethylene tetramine), OBSH (4,4-Oxybis (benzenesulfonyl hydrazide)) and AZDN (2,2-Azobis ( It may be advantageous to further improve the foaming rate to include at least one selected from the group consisting of isobutyronitrile)).

Meanwhile, the foaming agent may be included in an amount of 0.5 to 3.5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the main resin. If the foaming agent is less than 0.5 parts by weight with respect to 100 parts by weight of the main resin, the foaming rate may be lowered, and if it exceeds 3.5 parts by weight, the foaming rate is greatly increased, causing cracks in the final cured product of the adhesive composition I can.

Next, a moisture absorbent contained in the foamed adhesive composition for an automobile 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 11 parts by weight, preferably 5 to 9 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 11 parts by weight, the viscosity increases, which adversely affects the equipment dischargeability of the final mixture. And workability problems, and shear strength may decrease.

Next, a filler included in the foamed adhesive composition for an automobile 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 with equipment ejection, water resistance and impact strength may be deteriorated. If the average particle diameter exceeds 15 µm, the flexural strength decreases. There may be.

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 functions to improve the ratio of fracture mode cohesive failure (CF), and any filler having a shape that can be used to improve the ratio of failure mode cohesive failure (CF) in the art can be used without limitation. In addition, preferably, the third filler may be a plate-shaped filler.

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 in that the ratio of fracture mode cohesive failure (CF) decreases, 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 the ratio of fracture mode cohesive failure (CF), and preferably The first filler, the second 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 foamed adhesive composition for an automobile 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 the ratio of fracture mode cohesive failure (CF) may be insignificant, and if the weight ratio exceeds 1:1.5, the viscosity of the foamed adhesive composition for automobiles And there may be a problem that the desired level of specific gravity cannot be adjusted.

In addition, the foam-type adhesive composition for automobiles of the present invention may include 3 to 13 parts by weight of the filler, preferably 5 to 11 parts by weight, based on 100 parts by weight of the main resin to be described later. If the filler is less than 3 parts by weight based on 100 parts by weight of the main resin, the foamed adhesive composition for automobiles cannot exhibit the desired appropriate viscosity and specific gravity, and the ratio of fracture mode cohesive failure (CF) may be lowered. If the filler exceeds 13 parts by weight, the overall strength such as shear strength and impact strength may be lowered due to excessive viscosity and specific gravity.

In addition, the foamed adhesive composition for a vehicle according to the present invention may further include a physical property enhancer to improve the ratio of the fracture mode cohesive failure (CF).

The physical property enhancer can be used without limitation as long as it is a physical property enhancer that can be used to improve the ratio of fracture mode cohesive failure (CF) in the art. Preferably, the use of epoxy silane is It is easier to improve the ratio.

The physical property enhancer may be further included in an amount of 0.2 to 2.5 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the main resin. If the physical property enhancer is less than 0.2 parts by weight based on 100 parts by weight of the main resin, the degree of improvement in the ratio of fracture mode cohesive failure (CF) may be insignificant, and if it exceeds 2.5 parts by weight, storage stability decreases due to the effect of the unreacted product in the composite There may be a problem.

In addition, the foam-type 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 2 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 2 parts by weight based on 100 parts by weight of the main resin, a problem may occur that does not exhibit the desired level of viscosity, and if it exceeds 10 parts by weight, the viscosity of the adhesive composition is very high, resulting in poor workability. Can occur.

Meanwhile, the automotive adhesive composition according to the present invention may have a viscosity of 7,500 to 22,500 Pa·s, preferably 10,000 to 20,000 Pa·s, and a specific gravity of less than 1.3, preferably less than 1.25 at 20°C. I can.

The foamed adhesive composition for automobiles of the present invention has a high foaming rate, excellent shear strength, impact strength, and flexural strength, and does not generate cracks and has excellent 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 dimer acid-modified epoxy resin with a viscosity of 650 cps at 25°C, and a CTBN rubber flourishing epoxy resin with a viscosity of 45,000 cps at 75°C as a fourth epoxy resin in a weight ratio of 1: 1.15: 0.15: 0.15. Stirrer) was used to uniformly mix to prepare a main resin. At this time, the weight ratio of the urethane-modified epoxy resin and the CTBN-modified epoxy resin was 1:0.15. Thereafter, 2 parts by weight of an expandable foaming agent (Microsphere) as a blowing agent, 6.5 parts by weight of calcium oxide as a desiccant, 2.5 parts by weight of a needle-shaped calcium carbonate filler having an average particle diameter of 11 µm as a first filler, 2.5 parts by weight of a spherical calcium carbonate filler having an average particle diameter of 10 μm as a second filler, 2.5 parts by weight of a plate-shaped calcium carbonate filler having an average particle diameter of 14 μm as a third filler, 1.3 parts by weight of epoxy silane as a physical property enhancer, and a viscosity modifier. After 6 parts by weight of fumed silica having an average particle diameter of 0.3 μm was added, it was mixed again using a stirrer. Store the mixed composition in a low temperature chamber (-10℃) to lower the temperature, and add 6.5 parts by weight of dicyandiamide having an average particle diameter of 20 μm as a curing agent to 100 parts by weight of the main resin in the lowered temperature, and a curing accelerator. After 1.3 parts by weight of phenyl dimethyl urea was added and mixed using a stirrer, the mixed composition was removed using a paste mixer to remove microbubbles inside the sample to prepare a foam adhesive composition for automobiles. Was prepared.

<Examples 2 to 22 and Comparative Examples 1 to 9>

Prepared in the same manner as in Example 1, but as shown in Tables 1 to 5 below, the viscosity of each of the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin and their weight ratio, whether or not they are included, foaming agent By changing the content and the content of the filler, etc. to prepare a foam-type adhesive composition for automobiles as shown in Tables 1 to 5.

<Experimental Example 1: Physical properties of a foamed adhesive composition for automobiles>

In order to evaluate the physical properties of the foam-type adhesive composition for automobiles prepared in Examples and Comparative Examples, the following physical properties were evaluated and shown in Tables 1 to 5.

1. Shear strength measurement

Each of the foamed adhesive composition 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 a glass bead was used. The thickness was adjusted, the joint was fixed with a clip, and then 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 foamed adhesive composition 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 a glass bead was used. The thickness was adjusted, the joint was fixed with a clip, and then 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. Measurement of flexural strength

After applying the foam-type adhesive composition for automobiles according to Examples and Comparative Examples to a steel plate having a thickness of 0.8 mm and a width of 25 × 150 mm with a thickness of 1.5 mm and a length of 25 × 130 mm, respectively, at 180° C. using a hot air oven , After curing for 28 minutes, it was left at room temperature for 1 hour. And, the flexural strength was measured at a speed of 5 mm/min using a 3-point bending test method in a universal test machine (ZWICK-Z50, GERMANY).

4. Cold-resistant bending measurement

After applying the foamed adhesive composition for automobiles according to Examples and Comparative Examples to the center of a steel plate having a thickness of 0.8 mm and a width of 300 × 300 mm with a thickness of 1.5 mm and a width of 80 × 150 mm, using a hot air oven After curing at 180° C. for 28 minutes, it was left at room temperature for 1 hour. And, after standing at -30°C for 30 minutes, the amount of deformation of the corner is measured in an atmosphere of -30°C, and the average value is measured.

5. Impact strength measurement

Each of the foamed adhesive compositions for automobiles according to the Examples and Comparative Examples on two bent specimens having a thickness of 1.6 mm and a width of 20 × 90 mm was made into a thickness of 0.2 mm and a width of 20 × 30 mm, but the glass bead (glass bead) ) To adjust the thickness and fix the joint with a clip, and then 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%.

6. Fracture Mode Cohesive Failure (CF) Rate Measurement

Each of the foamed adhesive composition 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 a glass bead was used. The thickness was adjusted, the joint was fixed with a clip, and then 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.

7. Foaming rate measurement

Measure the weight in air (1) and weight in water (2) of a steel plate having a thickness of 0.8 mm and a width of 50 × 50 mm. The foamed adhesive composition for automobiles according to the Examples and Comparative Examples was applied to a steel sheet having a diameter of 10 mm in a length of 40 mm, and the weight in the air (3) and the weight in water (4) before curing were applied. Measure. After curing at 180°C for 28 minutes using a hot air oven, it was left at room temperature for 1 hour. Then, measure the weight in air (5) and weight in water (6) of the cured specimen. And, according to the following equation, the foaming rate was measured.

[Equation 1]

division Example
One Example
2 Example
3 Example
4 Example
5 Example
6 Example
7 First epoch
Sisuji Viscosity
(cps, 25℃) 12500 11500 13500 18000 12500 12500 12500 Second epoch
Sisuji Viscosity
(cps, 30℃) 110000 110000 110000 82000 50000 80000 140000 3rd epoch
Sisuji Viscosity
(cps, 25℃) 650 650 650 420 650 650 650 4th epoxy resin Viscosity
(cps, 75℃) 45000 45000 45000 61000 45000 45000 45000 Condition(1) (a+c+d)/b 0.53 0.52 0.53 0.97 1.163 0.73 0.42 Condition(2) ad/bc 7.9 7.2 8.5 31.9 17.3 10.8 6.2 Weight ratio of the first and second epoxy resins 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 Weight ratio of the first and third epoxy resins 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Weight ratio of the first and fourth epoxy resins 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Foaming agent content (parts by weight) 2 2 2 2 2 2 2 Filler content (parts by weight) 7.5 7.5 7.5 7.5 7.5 7.5 7.5 Shear strength (Mpa) 17 15 15 11 14 15 16 Water resistance (shear, Mpa) 10 9 9 6 7 9 9 Flexural strength ((kgf) 8 8 8 7 7 8 8 Cold-resistant bending (mm) 1.5 1.5 1.5 2 2 1.5 1.5 Impact strength (N/mm) 12 12 12 11 6 10 11 Breakdown mode (%, CF) 77 76 77 71 69 77 72 Foaming rate (%) 166 164 164 153 155 165 164

division Example
8 Example
9 Example
10 Example
11 Example
12 Example
13 Example
14 First epoch
Sisuji Viscosity
(cps, 25℃) 12500 12500 12500 12500 12500 12500 12500 Second epoxy resin Viscosity
(cps, 30℃) 110000 110000 110000 110000 110000 110000 110000 3rd epoch
Sisuji Viscosity
(cps, 25℃) 400 900 650 650 650 650 650 4th epoch
Sisuji Viscosity
(cps, 75℃) 45000 45000 30000 60000 75000 45000 45000 Condition(1) (a+c+d)/b 0.53 0.53 0.39 0.67 0.8 0.53 0.53 Condition(2) ad/bc 12.8 5.7 5.2 10.5 13.1 7.9 7.9 Weight ratio of the first and second epoxy resins 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:0.5 1:1.8 Weight ratio of the first and third epoxy resins 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Weight ratio of the first and fourth epoxy resins 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Foaming agent content (parts by weight) 2 2 2 2 2 2 2 Filler content (parts by weight) 7.5 7.5 7.5 7.5 7.5 7.5 7.5 Shear strength (Mpa) 15 15 16 16 14 14 10 Water resistance (shear, Mpa) 8 8 9 9 7 7 6 Flexural strength ((kgf) 6 7 6 7 3 6 6 Cold-resistant bending (mm) 1.5 1.5 1.5 1.5 3 2 1.5 Impact strength (N/mm) 11 10 11 10 6 6 10 Breakdown mode (%, CF) 76 77 76 74 71 73 72 Foaming rate (%) 163 165 164 165 158 159 157

division Example
15 Example
16 Example
17 Example
18 Example
19 Example
20 Example
21 First epoch
Sisuji Viscosity
(cps, 25℃) 12500 12500 12500 12500 12500 12500 12500 Second epoxy resin Viscosity
(cps, 30℃) 110000 110000 110000 110000 110000 110000 110000 3rd epoxy resin Viscosity
(cps, 25℃) 650 650 650 650 650 650 650 4th epoxy resin Viscosity
(cps, 75℃) 45000 45000 45000 45000 45000 45000 45000 Condition(1) (a+c+d)/b 0.53 0.53 0.53 0.53 0.53 0.53 0.53 Condition(2) ad/bc 7.9 7.9 7.9 7.9 7.9 7.9 7.9 Weight ratio of the first and second epoxy resins 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 Weight ratio of the first and third epoxy resins 1:0.01 1:0.5 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Weight ratio of the first and fourth epoxy resins 1:0.15 1:0.15 1:0.01 1:0.5 1:0.15 1:0.15 1:0.15 Foaming agent content (parts by weight) 2 2 2 2 0.1 5 2 Filler content (parts by weight) 7.5 7.5 7.5 7.5 7.5 7.5 1.5 Shear strength (Mpa) 15 11 15 11 15 14 14 Water resistance (shear, Mpa) 8 5 8 6 8 8 8 Flexural strength ((kgf) 6 6 3 6 6 6 6 Cold-resistant bending (mm) 2 2 3 1.7 1.7 2 2 Impact strength (N/mm) 9 9 7 9 10 8 8 Breakdown mode (%, CF) 57 72 71 72 69 52 53 Foaming rate (%) 151 154 152 153 122 173 154

division Example
22 Comparative example
One Comparative example
2 Comparative example
3 Comparative example
4 Comparative example
5 Comparative example
6 First epoch
Sisuji Viscosity
(cps, 25℃) 12500 5000 11500 9500 10500 12500 - Second epoch
Sisuji Viscosity
(cps, 30℃) 110000 130000 180000 155000 145000 110000 110000 3rd epoch
Sisuji Viscosity
(cps, 25℃) 650 800 400 150 960 1200 650 4th epoch
Sisuji Viscosity
(cps, 75℃) 45000 26000 26000 24000 18000 45000 45000 Condition(1) (a+c+d)/b 0.53 0.24 0.21 0.22 0.20 0.26 - Condition(2) ad/bc 7.9 1.3 4.2 9.8 1.3 1.4 - Weight ratio of the first and second epoxy resins 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 Weight ratio of the first and third epoxy resins 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Weight ratio of the first and fourth epoxy resins 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Foaming agent content (parts by weight) 2 2 2 2 2 2 2 Filler content (parts by weight) 15 7.5 7.5 7.5 7.5 7.5 7.5 Shear strength (Mpa) 12 10 11 10 9 11 8 Water resistance (shear, Mpa) 6 5 6 5 4 6 4 Flexural strength ((kgf) 5 3 3 3 3 3 5 Cold-resistant bending (mm) 2 3 3 3 3 3 2 Impact strength (N/mm) 8 7 7 8 7 8 10 Breakdown mode (%, CF) 69 59 58 59 57 61 67 Foaming rate (%) 151 147 145 144 143 145 156

division Comparative example
7 Comparative example
8 Comparative example
9 First epoch
Sisuji Viscosity
(cps, 25℃) 12500 12500 12500 Second epoch
Sisuji Viscosity
(cps, 30℃) - 110000 110000 3rd epoch
Sisuji Viscosity
(cps, 25℃) 650 - 650 4th epoch
Sisuji Viscosity
(cps, 75℃) 45000 45000 - Condition(1) (a+c+d)/b - - - Condition(2) ad/bc - - - Weight ratio of the first and second epoxy resins 1:1.15 1:1.15 1:1.15 Weight ratio of the first and third epoxy resins 1:0.15 1:0.15 1:0.15 Weight ratio of the first and fourth epoxy resins 1:0.15 1:0.15 1:0.15 Foaming agent content (parts by weight) 2 2 2 Filler content (parts by weight) 7.5 7.5 7.5 Shear strength (Mpa) 15 15 15 Water resistance (shear, Mpa) 7 7 7 Flexural strength ((kgf) 5 6 3 Cold-resistant bending (mm) 2 2 3 Impact strength (N/mm) 4 9 4 Breakdown mode (%, CF) 68 51 69 Foaming rate (%) 155 156 148

As can be seen from Tables 1 to 5, the viscosity of each of the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin, and their weight ratio, whether or not they are included, the content of the foaming agent, and Examples 1 to 3 and 6 to 11 satisfying all the content of the filler, etc., compared to Examples 4, 5, 12 to 22 and Comparative Examples 1 to 9, in which any one of them is omitted, shear strength, water resistance, flexural strength, At the same time, the impact strength and foaming rate were excellent, the rate of cohesive failure was high, and the cold-resistant bending was low.

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 (13)

A main resin comprising a first epoxy resin, a second epoxy resin, a third epoxy resin, and a fourth epoxy resin;
blowing agent;
Desiccant; And
Including, the first epoxy resin, the second epoxy resin, the third epoxy resin and the fourth epoxy resin satisfy all of the following conditions (1) and (2),
The first epoxy resin has a viscosity of 10,000 to 15,000 cps at 25°C,
The second epoxy resin has a viscosity of 65,000 to 150,000 cps at 30°C,
The third epoxy resin has a viscosity of 300 ~ 1000 cps at 25 ℃,
The fourth epoxy resin has a viscosity of 25,000 ~ 65,000 cps at 75 ℃ foam adhesive composition for automobiles:
(1) (a+c+d)/b ≥ 0.23
(2) ad/bc ≥ 1.6.
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) of the fourth epoxy resin at 75°C. delete 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,
The fourth epoxy resin is a CTBN rubber-modified epoxy resin, an automotive foam adhesive composition. The method of claim 1, wherein the main resin is
The foamed adhesive composition for automobiles comprising the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin in a weight ratio of 1: 0.8 to 1.5: 0.05 to 0.3: 0.05 to 0.3. The method of claim 1,
The second epoxy resin includes 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,
Foam adhesive composition for automobiles further comprising 2 to 11 parts by weight of a curing agent and 0.2 to 2.5 parts by weight of a curing accelerator based on 100 parts by weight of the main resin. The method of claim 1,
Foam adhesive composition for automobiles comprising 0.5 to 3.5 parts by weight of the foaming agent based on 100 parts by weight of the main resin. The method of claim 1,
Foam adhesive composition for automobiles comprising 3 to 11 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 foam-type adhesive composition for automobiles having 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 9,
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 to 18 μm. The method of claim 9,
The filler is a foam adhesive composition for automobiles 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,
Foam-type adhesive composition for automobiles comprising 3 to 13 parts by weight of the filler based on 100 parts by weight of the main resin. The method of claim 1,
Foam-type adhesive composition for automobiles further comprising 0.2 to 2.5 parts by weight of a physical property enhancer and 2 to 10 parts by weight of a viscosity modifier based on 100 parts by weight of the main resin.