KR102320967B1 - Adhesive composition for automobility - Google Patents

Abstract

The present invention relates to an adhesive composition for automobiles, and more particularly, to an adhesive composition for automobiles having low flowability, excellent shear strength, impact strength and peel strength, at the same time not generating cracks and having excellent elongation.

Description

Adhesive composition for automobiles {Adhesive composition for automobility}

The present invention relates to an adhesive composition for automobiles, and more particularly, to an adhesive composition for automobiles having low flowability, excellent shear strength, impact strength and peel strength, at the same time not generating cracks and having excellent elongation.

Recently, the automobile industry is trying to reduce the weight through high fuel efficiency engines in order to significantly reduce fuel consumption by vehicle type in accordance with strengthened legal regulations. The lightweight design of today's automobiles requires new bonding technologies with an increasing number of new materials or material mixtures, which enable the use of new materials, the bonding of new materials, and provide structural advantages to the bonded components.

The direction of technological development of structural adhesives is to improve the shortcomings of structural adhesives, not only to improve mechanical properties, but also to lower the price, and to reduce the curing time after bonding while lowering the price. Short is the development of adhesives.

On the other hand, it is an adhesive that can be used throughout the automobile and aerospace industries. It should be able to increase the strength in the bonded area by making the bonding between mechanical parts hard and increasing the rigidity in the bonding, and it should have high elongation at break and impact resistance do.

However, in the case of the conventional adhesive, it was not possible to achieve all of the effects of low flowability, excellent shear strength, impact strength, and thin film strength, and no cracks and excellent elongation at the same time. Accordingly, there is an urgent need to develop an adhesive composition having low flowability, excellent shear strength, impact strength and peel strength, and at the same time no cracking and excellent elongation.

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

The present invention has been devised to solve the above-described problems, and it is an object of the present invention to provide an adhesive composition for automobiles having low flowability, excellent shear strength, impact strength and peel strength, at the same time not generating cracks, and having excellent elongation.

In order to solve the above problems, the present invention provides a main resin having a first epoxy resin, a second epoxy resin, a third epoxy resin, and a fourth epoxy resin having different viscosities; desiccant; and a filler; the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin provide an adhesive composition for automobiles that satisfies all of the following conditions (1) and (2).

(1) d < a < b < c

(2) The weight ratio of the first epoxy resin and the second epoxy resin is 1: 0.08 to 0.6.

At this time, a is the viscosity at 25 ℃ of the first epoxy resin (cps), b is the viscosity at 75 ℃ of the second epoxy resin (cps), c is the viscosity at 30 ℃ of the third epoxy resin (cps) and d represents the viscosity (cps) at 25° C. of the fourth epoxy resin.

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 25,000 to 65,000 cps at 75° C., and the third The epoxy resin may have a viscosity of 65,000 to 150,000 cps at 30° C., and the fourth epoxy resin may have a viscosity of 300 to 1,000 cps at 25° C.

In addition, the first epoxy resin may be a bisphenol A-type epoxy resin, the second epoxy resin may be a CTBN rubber-modified epoxy resin, the third epoxy resin may be a urethane-modified epoxy resin, and the fourth epoxy The resin may be a dimer acid-modified epoxy resin.

In addition, the main resin may include the first epoxy resin, the third epoxy resin, and the fourth epoxy resin in a weight ratio of 1: 0.6 to 1.4: 0.06 to 0.27.

In addition, 3 to 11 parts by weight of a curing agent and 0.3 to 2.5 parts by weight of a curing accelerator based on 100 parts by weight of the main resin may be further included.

In addition, the desiccant may include calcium oxide.

In addition, the moisture absorbent may be included in an amount of 3 to 11 parts by weight based on 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.

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

In addition, 0.3 to 2.5 parts by weight of a physical property enhancer and 2 to 9 parts by weight of a viscosity enhancer may be further included with respect to 100 parts by weight of the main resin.

The adhesive composition for automobiles according to the present invention has low flowability, excellent shear strength, impact strength and peel strength, and at the same time does not generate cracks and has excellent elongation.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

The adhesive composition for automobiles 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 having different viscosities; desiccant; and a filler;

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

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

Accordingly, the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin provided in the adhesive composition for an automobile of the present invention satisfy all of the following conditions (1) and (2).

As condition (1), d < a < b < c, as condition (2), the weight ratio of the first epoxy resin and the second epoxy resin is 1: 0.08 to 0.6, preferably, the weight ratio is 1: 0.15 to 0.35 can be

At this time, a is the viscosity at 25 ℃ of the first epoxy resin (cps), b is the viscosity at 75 ℃ of the second epoxy resin (cps), c is the viscosity at 30 ℃ of the third epoxy resin (cps) and d represents the viscosity (cps) at 25° C. of the fourth epoxy resin.

If d < a < b < c in the above condition (1) is not satisfied, the shear strength, peel strength and impact strength may decrease, and flowability may increase, and in the above condition (2), the first epoxy resin And if the weight ratio of the second epoxy resin is less than 1: 0.08, flowability may increase, impact strength and/or peel strength may decrease, cracks may occur, and if the weight ratio exceeds 1: 0.6, shear strength and/or impact strength may be reduced, and cracks may occur.

Hereinafter, each configuration included in the adhesive composition for automobiles will be described in detail.

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

The first epoxy resin serves to improve the shear strength of the adhesive composition for automobiles, and any epoxy resin that can be used to improve shear strength in general 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 10,000 to 15,000 cps at 25° C. to satisfy the condition (1), and preferably a viscosity of 11,500 to 13,500 cps. If the viscosity at 25° C. of the first epoxy resin is less than 10,000 cps, it may be difficult to uniformly mix due to insufficient dispersibility when mixed with calcium carbonate and a curing agent, and there is a problem 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, and there may be a problem that the desired level of shear strength cannot be expressed because uncured parts may remain after curing. have.

In addition, the second epoxy resin performs a function of improving the impact strength of the adhesive composition for automobiles, and can be used without limitation, as long as it is an epoxy resin that can be used to improve impact strength conventionally in the art, preferably CTBN It may be a rubber-modified epoxy resin.

In addition, the second epoxy resin may have a viscosity of 25,000 to 65,000 cps at 75° C. to satisfy the condition (1), and preferably a viscosity of 30,000 to 60,000 cps. If the viscosity at 75° C. of the second epoxy resin is less than 25,000 cps or exceeds 65,000 cps, a problem of lowering impact strength and/or shear strength may occur.

And, the third epoxy resin serves to improve the impact strength and elongation of the adhesive composition for automobiles, and if it is an epoxy resin that can be used to improve impact strength and elongation in the art, it can be used without limitation, Preferably, a urethane-modified epoxy resin can be used.

In addition, the third epoxy resin may preferably have a viscosity of 65,000 to 150,000 cps at 30° C. to satisfy the above condition (1), and more preferably a viscosity of 80,000 to 140,000 cps. If the viscosity at 30° C. of the third epoxy resin is less than 65,000 cps, the impact strength may be lowered, the flowability may be increased, and if the viscosity exceeds 150,000 cps, heat of mixing occurs to reduce thermal stability, It may reduce the equipment ejection property of the final mixture, and there may be a problem that cracks cannot be prevented after curing of the composition, and the elongation may be lowered.

And, the fourth epoxy resin functions to show a desired level of viscosity by controlling the viscosity of the adhesive composition for automobiles, and if it is an epoxy resin that can be used to control the viscosity in the art, it can be used without limitation, Preferably, it may be a dimer acid modified epoxy resin.

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

Meanwhile, the main resin may include the first epoxy resin, the third epoxy resin, and the fourth epoxy resin in a weight ratio of 1: 0.6 to 1.4: 0.06 to 0.27, preferably 1: 0.7 to 1.3: 0.1 to It may be included in a weight ratio of 0.24. If the weight ratio of the first epoxy resin and the third epoxy resin is less than 1: 0.6, there may be a problem that the desired level of impact strength and elongation cannot be expressed, and when the weight ratio exceeds 1: 1.4, the desired level of There may be a problem that shear strength cannot be expressed. In addition, if the weight ratio of the first epoxy resin and the fourth epoxy resin is less than 1: 0.06, the occurrence of cracks after curing of the adhesive composition for automobiles cannot be prevented, and the elongation may be reduced, and the weight ratio exceeds 1: 0.27. If you do, there may be a problem in that the desired level of shear strength cannot be expressed.

Next, a curing agent and a curing catalyst that may be further included in the adhesive composition for automobiles according to the present invention will be described.

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

There is no limitation on the properties of the curing agent, and for example, the curing agent may be in a solid or liquid phase. When the property of the curing agent is a solid phase, 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 adhesive composition for automobiles according to the present invention may contain 3 to 11 parts by weight of a 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 based on 100 parts by weight of the main resin, the flowability increases and the adhesive composition for automobiles is not cured to the desired level, so the shear strength, impact strength and peel strength may decrease, and the curing agent When is more than 11 parts by weight, cracks may occur and the elongation may decrease.

The curing accelerator may be used without limitation as long as it is a material that can be used as a curing accelerator conventionally in the art, and may preferably be phenyl dimethyl urea (Phenyl Dimethyl Urea). In addition, there is no limitation on the properties of the curing accelerator, and for example, the curing accelerator may be in a solid or liquid phase, and preferably, the curing accelerator may be in a solid phase.

The curing accelerator may be further included in an amount of 0.3 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 0.3 parts by weight based on 100 parts by weight of the main resin, it may not be cured to the desired level, so there may be a problem in expressing the desired strength, and if it exceeds 2.5 parts by weight, the storage property may be reduced. .

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

The desiccant may be included in an amount of 3 to 11 parts by weight, 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 water resistance is lowered, and if it exceeds 11 parts by weight, the viscosity increases and adversely affects the discharging property of the final mixture, and there is a problem in workability. There may be, and shear strength and elongation may be reduced.

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

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, and preferably a first filler, a second filler, and a third filler having different shapes. can all be provided.

The first filler serves to control the viscosity and specific gravity, and any filler having a shape that can be used to control the viscosity and specific gravity can be used without limitation, preferably, the first filler is needle-like in the art. It may be a type 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 may increase and there may be a problem in discharging the equipment, the impact strength may decrease, and if the average particle diameter exceeds 15 μm, there may be a problem of increasing the flowability. can

The second filler serves to control the viscosity and specific gravity, and any filler having a shape that can be used to control the viscosity and specific gravity can be used without limitation, preferably, the second filler is spherical It may be a type 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 μm, there may be a problem in that the impact strength is decreased because brittleness increases and becomes hard, and if the average particle diameter exceeds 14 μm, there is a property of reducing brittleness and flexibility, so shear strength There may be a problem with decreasing

The third filler serves to improve peel strength, and any filler having a shape that can be used to improve peel strength in general in the art can be used without limitation, and preferably, the third filler is a plate-shaped filler. 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 of lowering peel strength, and if the average particle diameter exceeds 18 μm, there may be a problem of reducing impact strength.

The first filler, the second filler and the third filler may be used without limitation as long as the fillers capable of expressing the above-described shape and the above-described effects are conventionally used in the art, and preferably, the first, second, and third fillers and The third filler may be calcium carbonate.

On the other hand, the filler is 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 1: 0.7 ~ 1.4: It may be included in a weight ratio of 0.7 to 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 that the viscosity and specific gravity of the adhesive composition for automobiles cannot be adjusted to a desired level. In addition, if the weight ratio of the first and third fillers 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 adhesive composition for automobiles can be adjusted to a desired level. There may be unsolvable problems.

In addition, the adhesive composition for automobiles of the present invention may contain 8 to 18 parts by weight of the filler, preferably 9 to 16 parts by weight of the filler, based on 100 parts by weight of the main resin. 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, peel strength may be reduced, and if the filler exceeds 18 parts by weight, viscosity and As the specific gravity becomes excessive, the problem of lowering the overall strength such as shear strength and impact strength may occur.

In addition, the adhesive composition for automobiles according to the present invention may further include a physical property enhancer to improve peel strength.

The physical property enhancer can be used without limitation as long as it is a physical property enhancer that can be used to improve peel strength in general in the art, and preferably, it is easier to use epoxy silane to improve peel strength.

The physical property enhancer may be further included in an amount of 0.3 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 0.3 parts by weight based on 100 parts by weight of the main resin, the degree of improvement in peel strength may be insignificant. .

In addition, the adhesive composition for automobiles according to the present invention may further include a viscosity enhancer in order to improve the viscosity and reduce the flowability to prevent the composition from flowing.

The viscosity enhancing agent can be used without limitation as long as it can improve viscosity and reduce flowability in the art, and fumed silica can be preferably used.

There is no limitation in the properties and shape of the viscosity modifier, and for example, the viscosity modifier may be in a solid phase. When the viscosity modifier is in a solid phase, 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 enhancing agent may be further included in an amount of 2 to 9 parts by weight, preferably 3 to 8 parts by weight, based on 100 parts by weight of the main resin. If the viscosity reinforcing agent is less than 2 parts by weight based on 100 parts by weight of the main resin, the flowability may be excessive, and the shear strength and impact strength may be reduced. There may be a problem that the elongation is lowered afterward.

The adhesive composition for automobiles according to the present invention has low flowability, excellent shear strength, impact strength and peel strength, and at the same time does not generate cracks and has excellent elongation.

The present invention will be described in more detail through the following examples, but the following examples are not intended to limit the scope of the present invention, which should be construed 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 CTBN rubber-modified epoxy resin having a viscosity of 45,000 cps at 75 ° C as a second epoxy resin, and a third epoxy resin having a viscosity at 30 ° C. Urethane-modified epoxy resin of 110,000 cps and dimer acid-modified epoxy resin having a viscosity of 650 cps at 25°C as the fourth epoxy resin in a weight ratio of 1: 0.33: 1: 0.167 using a stirrer, a mixing equipment, uniformly The main resin was prepared by mixing thoroughly. Then, based on 100 parts by weight of the main resin, 6.67 parts by weight of calcium oxide as a moisture absorbent, 4 parts by weight of needle-shaped calcium carbonate filler having an average particle diameter of 11 μm as the first filler, and spherical particles having an average particle diameter of 10 μm as the second filler 4 parts by weight of a calcium carbonate filler, 4 parts by weight of a plate-like calcium carbonate filler having an average particle diameter of 14 μm as the third filler, 1.33 parts by weight of epoxy silane as a physical property enhancer, and fumed silica having an average particle diameter of 0.3 μm as a viscosity enhancer ) was added in 5.33 parts by weight and then mixed again using a stirrer. The mixed composition was stored in a low temperature chamber (-10°C) to lower the temperature, and 6.67 parts by weight of dicyandiamide having an average particle diameter of 20 μm as a curing agent based on 100 parts by weight of the main resin in the composition at which the temperature was lowered, and a curing accelerator. After adding 1.33 parts by weight of rhophenyl dimethyl urea and mixing using a stirrer, the mixed composition was removed by using a paste mixer to remove microbubbles inside the sample to prepare an adhesive composition for automobiles. .

<Examples 2 to 25 and Comparative Examples 1 to 6>

It was prepared in the same manner as in Example 1, except that the weight ratio of the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin, the viscosity of each, and whether they were included, etc. were changed as shown in Tables 1 to 5 An adhesive composition for automobiles was prepared.

<Experimental Example 1: Physical properties of adhesive composition for automobiles before curing>

In order to evaluate the physical 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 below.

1. Flow measurement

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

<Experimental Example 2: Physical properties of adhesive composition for automobiles after curing>

In order to evaluate the physical properties after 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 below.

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 × height of 25 × 150 mm was 0.2 mm thick and a width × length 25 × 12.5 mm, but the thickness using a glass bead 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. Then, the shear strength was measured by applying a tensile load in the 180° direction at a speed of 5 mm/min in a universal test machine (ZWICK-Z50, GERMANY).

2. Measurement of failure mode cohesive failure (CF) ratio

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 × height of 25 × 150 mm was 0.2 mm thick and a width × length 25 × 12.5 mm, but the thickness using a glass bead 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. Then, the shear strength was measured by applying a tensile load in the 180° direction 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, the Cohesive Failure (CF) in which the adhesive itself is destroyed, and the Substrate Failure (SF) in which the adherend itself is destroyed. The ratio of cohesive failure (CF) among failure modes was measured.

3. T peel strength measurement

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples on two steel plates having a thickness of 0.8 mm, width × height 25 × 150 mm, thickness 0.2 mm, width × length 25 × 100 mm, but using a glass bead (glass bead) 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 cured product at 180° and fix each to the clamp part of a universal test machine (ZWICK-Z50, GERMANY), and apply a tensile load in the 180° direction at a speed of 50 mm/min. added. At this time, the T peel strength value was averaged from the load-displacement curve on the tensile tester.

4. Elongation measurement

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples was applied to a dumbbell-shaped tensile specimen frame with a thickness of 3 mm and a width × length of 20 × 160 mm to which a release agent was sufficiently applied, and cured at 180° C. for 28 minutes using a hot air oven. Then, it was left at room temperature for 1 hour. Then, each tensile specimen was separated, the gage distance of the specimen was marked according to the standard, and the specimen was fixed to the clamp part of the universal test machine (Universal test machine, ZWICK-Z50, GERMANY) on both sides. Thereafter, a load was applied at a tensile rate of 50 mm/min and the elongation at break was measured.

5. 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 a width of 20 × 90 mm had a thickness of 0.2 mm and a width of 20 × 30 mm, and a glass bead was applied. 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. And each specimen was impacted using an impact tester (CEAST9350, INSTRON, U.S.A.) under the conditions of a weight of 45 kg, a height of 0.2 m, and a speed of 2 m/s. At this time, the impact strength value was recorded as the impact strength value at the point where the peak was 25% from the starting point (time point) and the average load at the point where it was 10% from the end point.

division Example
One Example
2 Example
3 Example
4 Example
5 Example
6 No. 1 epoxy resin Viscosity (cps, 25℃) 12,500 8,000 11,500 13,500 17,000 12,500 2nd epoxy resin Viscosity (cps, 75℃) 45,000 45,000 45,000 45,000 45,000 18,000 3rd epoxy resin Viscosity (cps, 30℃) 110,000 110,000 110,000 110,000 110,000 110,000 4th epoxy resin Viscosity (cps, 25℃) 650 650 650 650 650 650 Weight ratio of the first and second epoxy resins 1:0.33 1:0.33 1:0.33 1:0.33 1:0.33 1:0.33 Weight ratio of the first and third epoxy resins 1:1 1:1 1:1 1:1 1:1 1:1 1st, 4th epoxy resin weight ratio 1:0.167 1:0.167 1:0.167 1:0.167 1:0.167 1:0.167 Physical properties before curing Flowability (mm) 3 3.9 3.1 2.9 2.8 3.1 Physical properties after curing Shear strength (Mpa) 22 15 21 20 14 12 Destruction mode (%, CF) 90 91 90 90 88 80 T peel strength (N/25mm) 265 221 258 260 252 240 Elongation (%) 5 5 5 4.9 2.8 5 Impact strength (N/mm) 27 26 27 27 27 14

division Example
7 Example
8 Example
9 Example
10 Example
11 Example
12 No. 1 epoxy resin Viscosity (cps, 25℃) 12,500 12,500 12,500 12,500 12,500 12,500 2nd epoxy resin Viscosity (cps, 75℃) 30,000 60,000 75,000 45,000 45,000 45,000 3rd epoxy resin Viscosity (cps, 30℃) 110,000 110,000 110,000 50,000 80,000 140,000 4th epoxy resin Viscosity (cps, 25℃) 650 650 650 650 650 650 Weight ratio of the first and second epoxy resins 1:0.33 1:0.33 1:0.33 1:0.33 1:0.33 1:0.33 Weight ratio of the first and third epoxy resins 1:1 1:1 1:1 1:1 1:1 1:1 1st, 4th epoxy resin weight ratio 1:0.167 1:0.167 1:0.167 1:0.167 1:0.167 1:0.167 Physical properties before curing Flowability (mm) 3.0 3.0 2.8 5.6 3.2 3.0 Physical properties after curing Shear strength (Mpa) 20 22 19 20 21 22 Destruction mode (%, CF) 90 90 86 90 90 90 T peel strength (N/25mm) 260 262 246 253 260 265 Elongation (%) 5 5 5 4.7 5 4.9 Impact strength (N/mm) 26 25 13 19 26 26

division Example
13 Example
14 Example
15 Example
16 Example
17 Example
18 No. 1 epoxy resin Viscosity (cps, 25℃) 12,500 12,500 12,500 12,500 12,500 12,500 2nd epoxy resin Viscosity (cps, 75℃) 45,000 45,000 45,000 45,000 45,000 45,000 3rd epoxy resin Viscosity (cps, 30℃) 170,000 110,000 110,000 110,000 110,000 110,000 4th epoxy resin Viscosity (cps, 25℃) 650 200 1200 650 650 650 Weight ratio of the first and second epoxy resins 1:0.33 1:0.33 1:0.33 1:0.16 1:0.33 1:0.33 Weight ratio of the first and third epoxy resins 1:1 1:1 1:1 1:1 1:0.5 1:0.7 1st, 4th epoxy resin weight ratio 1:0.167 1:0.167 1:0.167 1:0.167 1:0.167 1:0.167 Physical properties before curing Flowability (mm) 2.9 3 2.9 3 3.8 3.1 Physical properties after curing Shear strength (Mpa) 21 22 21 25 22 22 Destruction mode (%, CF) 75 90 90 90 90 90 T peel strength (N/25mm) 265 188 177 250 263 265 Elongation (%) 3.7 5 4.3 5 2.8 4.8 Impact strength (N/mm) 25 27 25 30 18 25

division Example
19 Example
20 Example
21 Example
22 Example
23 Example
24 No. 1 epoxy resin Viscosity (cps, 25℃) 12,500 12,500 12,500 12,500 12,500 12,500 2nd epoxy resin Viscosity (cps, 75℃) 45,000 45,000 45,000 45,000 45,000 45,000 3rd epoxy resin Viscosity (cps, 30℃) 110,000 110,000 110,000 110,000 110,000 110,000 4th epoxy resin Viscosity (cps, 25℃) 650 650 650 650 650 650 Weight ratio of the first and second epoxy resins 1:0.33 1:0.33 1:0.33 1:0.33 1:0.33 1:0.33 Weight ratio of the first and third epoxy resins 1:1.3 1:1.5 1:1 1:1 1:1 1:1 1st, 4th epoxy resin weight ratio 1:0.167 1:0.167 1:0.03 1:0.1 1:0.24 1:0.3 Physical properties before curing Flowability (mm) 3.0 2.9 2.8 2.9 3.2 4.2 Physical properties after curing Shear strength (Mpa) 20 14 21 22 20 14 Destruction mode (%, CF) 90 90 77 90 90 90 T peel strength (N/25mm) 265 264 231 255 264 252 Elongation (%) 5 4.9 2.9 4.8 5 4.9 Impact strength (N/mm) 27 26 23 26 27 25

division comparative example
One comparative example
2 comparative example
3 comparative example
4 comparative example
5 comparative example
6 No. 1 epoxy resin Viscosity (cps, 25℃) 12,500 12,500 12,500 12,500 12,500 - 2nd epoxy resin Viscosity (cps, 75℃) 75,000 45,000 45,000 45,000 45,000 45,000 3rd epoxy resin Viscosity (cps, 30℃) 50,000 110,000 110,000 - 110,000 110,000 4th epoxy resin Viscosity (cps, 25℃) 650 650 650 650 - 650 Weight ratio of the first and second epoxy resins 1:0.33 1:0.33 1:0.33 1:0.33 1:0.33 - Weight ratio of the first and third epoxy resins 1:1 1:0.03 1:0.8 - 1:1 - 1st, 4th epoxy resin weight ratio 1:0.167 1:0.167 1:0.167 1:0.167 - - Physical properties before curing Flowability (mm) 4.7 5 2 6.8 3 3.1 Physical properties after curing Shear strength (Mpa) 19 22 17 21 21 11 Destruction mode (%, CF) 88 60 70 90 75 90 T peel strength (N/25mm) 252 180 250 259 261 258 Elongation (%) 4.9 5 2 2 1.7 5 Impact strength (N/mm) 11 30 18 12 17 30

As can be seen from Tables 1 to 5 above,

Examples 1, 3, 4, 7, 8, which satisfy all of the weight ratio of the first epoxy resin, the second epoxy resin, the third epoxy resin, and the fourth epoxy resin, each viscosity and whether or not according to the present invention, 11, 12, 16, 18, 19, 22 and 23, Examples 2, 5, 6, 9, 10, 13, 14, 15, 17, 20, 21, 24 and Comparative Example 1 in which any one of them is omitted ~ 6, the composition did not flow due to low flowability, the ratio of cohesive failure was high, and the shear strength, T-peel strength, impact strength and elongation were all excellent at the same time.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same spirit. , changes, deletions, additions, etc. may easily suggest other embodiments, but this will also fall within the scope of the present invention.

Claims (12)

A first epoxy resin having a viscosity of 10,000 to 15,000 cps at 25°C, a second epoxy resin having a viscosity of 25,000 to 65,000 cps at 75°C, a third epoxy resin having a viscosity of 65,000 to 150,000 cps at 30°C, and a viscosity at 25°C Main resin having a fourth epoxy resin of 300 ~ 1,000 cps;
desiccant; and
Including; filler;
The first epoxy resin, the second epoxy resin, the third epoxy resin and the fourth epoxy resin is an adhesive composition for automobiles satisfying all of the following conditions (1) and (2):
(1) d < a < b < c
(2) A weight ratio of the first epoxy resin and the second epoxy resin is 1: 0.08 to 0.6.
In this case, a is the viscosity (cps) at 25 ° C. of the first epoxy resin, b is the viscosity (cps) at 75 ° C. of the second epoxy resin, c is the viscosity at 30 ° C. of the third epoxy resin (cps) and d represents the viscosity (cps) at 25° C. of the fourth epoxy resin. delete According to claim 1,
The first epoxy resin is a bisphenol A type epoxy resin,
The second epoxy resin is a CTBN rubber-modified epoxy resin,
The third epoxy resin is a urethane-modified epoxy resin,
The fourth epoxy resin is a dimer acid-modified epoxy resin adhesive composition for automobiles. According to claim 1,
The main resin is an adhesive composition for automobiles comprising the first epoxy resin, the third epoxy resin, and the fourth epoxy resin in a weight ratio of 1: 0.6 to 1.4: 0.06 to 0.27. According to claim 1,
The adhesive composition for automobiles further comprising 3 to 11 parts by weight of a curing agent and 0.3 to 2.5 parts by weight of a curing accelerator based on 100 parts by weight of the main resin. According to claim 1,
The moisture absorbent is an adhesive composition for automobiles comprising calcium oxide. According to claim 1,
An adhesive composition for automobiles comprising 3 to 11 parts by weight of the moisture absorbent based on 100 parts by weight of the main resin. According to claim 1,
The filler is an adhesive composition for automobiles having at least two types selected from the group consisting of a first filler, a second filler, and a third filler having different shapes. 9. The method of claim 8,
The first filler is a needle-shaped filler having an average particle diameter of 7 to 15㎛,
The second filler is a spherical filler having an average particle diameter of 6 to 14 μm,
The third filler is an adhesive composition for automobiles that is a plate-shaped filler having an average particle diameter of 10 to 18㎛. 9. The method of claim 8,
The filler is an 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. According to claim 1,
An adhesive composition for automobiles comprising 8 to 18 parts by weight of the filler based on 100 parts by weight of the main resin. According to claim 1,
The adhesive composition for automobiles further comprising 0.3 to 2.5 parts by weight of a physical property enhancer and 2 to 9 parts by weight of a viscosity enhancer based on 100 parts by weight of the main resin.