KR102138716B1 - 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, and no cracking, and excellent elongation and water resistance. 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 adhesive composition for automobiles having low flowability, excellent shear strength, impact strength, and peel strength, and no cracking, and excellent elongation and water resistance. will be.

The automobile industry has recently attempted to reduce the fuel consumption by vehicle type through a high fuel economy engine in accordance with strengthening legal regulations. Today's automotive lightweight designs require new bonding techniques with the increase of new materials or material mixtures, which allow the use of new materials, bonding new materials, and provide structural advantages to bonded components.

The technical development direction of structural adhesives is to improve the shortcomings of structural adhesives, which not only improves mechanical properties, but also lowers the price of one of the most important ones and increases the pot life after mixing and the curing time after bonding. It is the development of a short adhesive.

On the other hand, with adhesives that can be used throughout the automobile and aerospace industries, it should be possible to increase the strength of the bonded area by hardening the bonds between mechanical parts and increasing the stiffness of the bonds. do.

However, in the case of the conventional adhesive, the strength is relatively low when stress is applied perpendicularly to the adhesive surface. That is, the adhesive surface is high in strength, but is likely to fall in a direction perpendicular to the adhesive surface. Accordingly, there is an urgent need to develop a structural adhesive composition having low flowability, superior shear strength, impact strength, and peel strength, and no cracking, and excellent elongation and water resistance.

KR 10-1991-0015676 A (Public date: 1991.09.30)

The present invention has been devised to solve the above-mentioned problems, provides a low adhesiveness, excellent shear strength, impact strength, and peel strength, and provides an adhesive composition for automobiles having excellent elongation and water resistance while preventing cracking. There is a purpose.

In order to solve the above-mentioned problems, the present invention, the first resin having a second epoxy resin, a second epoxy resin and a third epoxy resin; And a curing agent, wherein the first epoxy resin, the second epoxy resin, and the third epoxy resin provide an automotive adhesive composition that satisfies the following conditions (1) and (2).

(One)

(2)

At this time, the a is the viscosity of the first epoxy resin at 25 ℃ (cps), b is the viscosity of the second epoxy resin at 30 ℃ (cps) and c is the viscosity of the third epoxy resin at 25 ℃ (cps) Indicates.

According to an embodiment of the present invention, the first epoxy resin, the second epoxy resin and the third epoxy resin may satisfy the following condition (1) and condition (2).

(One)

임.(2)

being.

In addition, 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 25°C. May be 300 to 1000 cps.

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

Further, 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 CTBN-modified epoxy resin in a weight ratio of 1: 0.05 to 0.3.

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

In addition, the calcium compound may further include 14 to 35 parts by weight based on 100 parts by weight of the main resin.

In addition, it may further include 0.3 to 3 parts by weight of a physical property enhancer with respect to 100 parts by weight of the main resin.

In addition, the viscosity modifier may be further included in an amount of 1.5 to 10 parts by weight based on 100 parts by weight of the main resin.

The adhesive composition for automobiles of the present invention has low flowability, excellent shear strength, impact strength, and peel strength, and does not crack, and has excellent elongation and water resistance.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily practice. The present invention can be implemented 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 subject resin having a first epoxy resin, a second epoxy resin, and a third epoxy resin; And a curing agent.

Prior to the description of each component included in the adhesive composition for an automobile according to the present invention, the first epoxy resin, the second epoxy resin and the third epoxy resin provided in the subject resin of the automotive adhesive composition of the present invention have the following conditions ( The reason for satisfying 1) and condition (2) will be explained first.

When the viscosity of the adhesive composition for automobiles is low, there may be a problem in that flowability is low to a desired level, and shear strength, impact strength, and peel strength cannot exhibit excellent effects. In addition, when the viscosity of the adhesive composition for automobiles is high, crack generation cannot be prevented at a desired level, elongation may be lowered, 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 provided in the main resin of the automotive adhesive composition of the present invention satisfy the following conditions (1) and (2) to solve these problems do.

이고, 바람직하게는

일 수 있으며, 조건 (2)로써,

이고, 바람직하게는

일 수 있다.As condition (1),

Is, preferably

Can be, as condition (2),

Is, preferably

Can be

At this time, the a is the viscosity of the first epoxy resin at 25 ℃ (cps), b is the viscosity of the second epoxy resin at 30 ℃ (cps) and c is the viscosity of the third epoxy resin at 25 ℃ (cps) Indicates.

이 0.27 미만이면 목적하는 수준의 전단강도, 충격강도 및 신율을 발현할 수 없고, 자동차용 접착 조성물이 목적하는 점도 수준에 비하여 작은 점도를 나타내어 흐름성이 높아지는 문제가 발생할 수 있다. 또한, 만일 상기 조건 (2)에서

이 4.3 미만이면 목적하는 수준의 충격강도 및 신율을 발현할 수 없는 문제가 발생할 수 있다.If, in the condition (1) above

If it is less than 0.27, a desired level of shear strength, impact strength, and elongation cannot be expressed, and the adhesive composition for automobiles exhibits a small viscosity compared to a desired viscosity level, which may cause a problem of high flowability. Also, if the condition (2) above

If it is less than 4.3, a problem that a desired level of impact strength and elongation cannot be expressed may occur.

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

First, a main resin having a first epoxy resin, a second epoxy resin, and a third epoxy resin 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 can be used without limitation as long as it is an epoxy resin that can be generally used in the art to improve shear strength, preferably bisphenol A type It may be an epoxy resin.

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

In addition, the second epoxy resin serves to improve the impact strength and elongation of the adhesive composition for automobiles. Any epoxy resin that can be used to improve the impact strength and elongation in the art can be used without limitation. Preferably, it may be one or more selected from urethane-modified epoxy resins and CTBN (Carboxyl Terminated Butadiene Acrylonitrile)-modified epoxy resins, and more preferably, a urethane-modified epoxy resin and CTBN-modified epoxy resins may be mixed and used.

When using a mixture of urethane-modified epoxy resin and CTBN-modified epoxy resin as described above, the second epoxy resin is urethane-modified epoxy resin and CTBN-modified epoxy resin in a weight ratio of 1: 0.05 to 0.3, preferably 1: 0.1 ~ 0.25 weight ratio. If the weight ratio of the urethane-modified epoxy resin and CTBN-modified epoxy resin is less than 1: 0.05, toughness cannot be imparted to the epoxy cured product, impact resistance is lowered, and agglomeration and destruction ratio may be lowered, and the weight ratio is 1: If it exceeds 0.3, toughness may be imparted, but water resistance may be deteriorated 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 to satisfy the conditions (1) and (2), and more preferably 80,000 to 140,000 cps of viscosity. . If the viscosity of the second epoxy resin at 30° C. is less than 65,000 cps, there may be a problem that the flowability of the final adhesive composition increases, and when the viscosity exceeds 150,000 cps, mixed heat is generated to deteriorate thermal stability. It can reduce the equipment ejection property of the mixture, it is not possible to prevent the occurrence of cracks after curing the composition, there may be a problem that the elongation may be lowered.

In addition, the third epoxy resin serves to exhibit a desired level of viscosity by controlling the viscosity of the adhesive composition for automobiles. Any epoxy resin that can be used to control the viscosity in the art can be used without limitation. It may be preferably a dimer acid modified epoxy resin.

In addition, the third epoxy resin may preferably have a viscosity of 300 to 1,000 cps at 25°C to satisfy the condition (1), and more preferably a viscosity of 400 to 900 cps. If the viscosity of the third epoxy resin at 25° C. is less than 300 cps or exceeds 1,000 cps, it affects the equipment ejection property, and the peel strength can be lowered 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 1: 0.9 ~ 1.4: 0.1 ~ 0.25 in a weight ratio It can contain. 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 and elongation cannot be expressed, and if the weight ratio exceeds 1: 1.5, the desired level There may be a problem that 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, crack generation after curing of the adhesive composition for automobiles cannot be prevented, elongation may deteriorate, and the weight ratio exceeds 1: 0.3. If there is, there may be a problem that the desired level of shear strength cannot be expressed.

Next, the curing agent 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 to cure epoxy resins in the art, and may be preferably dicyandiamide.

The properties of the curing agent are not limited, and for example, the curing agent may be solid or liquid. 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.

In addition, the adhesive composition for automobiles according to the present invention may contain 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 based on 100 parts by weight of the main resin, the flowability increases and the shear strength, impact strength, and peel strength may deteriorate as the adhesive composition for automobiles does not harden to the desired level. If it exceeds 12 parts by weight, cracks may occur, and a problem that the elongation decreases may occur.

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

The curing accelerator may be used without limitation as long as it can be used as a curing accelerator in the art, preferably phenyl dimethyl urea (Phenyl Dimethyl Urea). In addition, the properties of the curing accelerator are not limited, and for example, the curing accelerator may be solid or liquid, and preferably, the curing accelerator may be solid.

The curing accelerator may be further included in 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 based on 100 parts by weight of the main resin, there may be a problem in expressing the desired strength because it is not cured to a desired level, and if it exceeds 3 parts by weight, a problem that storage property may be deteriorated may occur .

In addition, the adhesive composition for automobiles according to the present invention may further include a calcium compound.

The calcium compound is not limited as long as it can function to improve moisture absorption, viscosity and specific gravity control, and peel strength. For example, the calcium compound is a calcium oxide for absorbent, calcium carbonate for viscosity and specific gravity control, and calcium carbonate for improving peel strength. Any one or more selected from the group consisting of may be used alone or in combination.

The calcium compound may be further included in 14 to 35 parts by weight, preferably 21 to 29 parts by weight based on 100 parts by weight of the main resin. If the calcium compound is out of the above content range, shear strength, impact strength, peel strength and water resistance may deteriorate.

In addition, the adhesive composition for automobiles according to the present invention may further include a 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 generally used in the art to improve the peel strength, and preferably, an epoxy silane is used to improve the peel strength.

The physical property enhancer 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 physical property enhancer is less than 0.3 parts by weight with respect to 100 parts by weight of the main resin, the degree of peel strength improvement may be insignificant, and if it exceeds 3 parts by weight, there may be a problem that adhesive strength decreases due to the influence in the complex of the unreacted material.

In addition, the adhesive composition for automobiles according to the present invention may further include a viscosity modifier in order to improve viscosity and lower 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.

The properties and shape of the viscosity modifier are not limited, and for example, the viscosity modifier may be solid. When the viscosity modifier is in the 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 modifier may be further included in 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 with respect to 100 parts by weight of the main resin, a problem of increasing flowability may occur, and if it exceeds 10 parts by weight, the viscosity of the adhesive composition becomes very high, resulting in poor workability and elongation after curing. The problem of deterioration may occur.

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

The adhesive composition for automobiles of the present invention has low flowability, excellent shear strength, impact strength, and peel strength, and does not crack, and has excellent elongation and water resistance.

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 interpreted to help understand the present invention.

<Example 1>

Bisphenol A type epoxy resin having a viscosity of 12,500 cps at 25°C as the first epoxy resin, and urethane-modified epoxy resin and CTBN-modified epoxy resin having a viscosity of 110,000 cps at 30°C respectively as the second epoxy resin, as the third epoxy resin A dimeric acid-modified epoxy resin having a viscosity of 650 cps at 25°C was uniformly mixed using a mixing equipment, a stirrer, in a weight ratio of 1: 1.15: 0.15 to prepare a main resin. At this time, the weight ratio of the urethane-modified epoxy resin and CTBN-modified epoxy resin was 1: 0.15. To the prepared main resin, 25 parts by weight of calcium carbonate with respect to 100 parts by weight of the main resin, 1.5 parts by weight of epoxy silane as a property enhancer and 6 parts by weight of fumed silica having an average particle size of 0.3 µm as a viscosity modifier were added. Then, it was mixed again using a stirrer. The mixed composition is stored in a low-temperature chamber (-10°C) to lower the temperature, and to the composition having a lower temperature, 6 parts by weight of dicyandiamide having an average particle diameter of 20 µm as a curing agent relative to 100 parts by weight of the main resin, and a curing accelerator After adding phenyl dimethyl urea to 1.5 parts by weight, the mixture was mixed using a stirrer, and the mixed composition was removed using a paste mixer to remove micro bubbles inside the sample to prepare an adhesive composition for automobiles. .

<Examples 2 to 15 and Comparative Examples 1 to 9>

Prepared in the same manner as in Example 1, but by changing the viscosity and weight ratio of each of the first epoxy resin, the second epoxy resin, the third epoxy resin, the content of the curing agent and the content of the viscosity modifier as shown in Tables 1 to 4 below. The adhesive compositions for automobiles as shown in Tables 1 to 4 were prepared.

<Experimental Example 1: Pre-curing properties of the adhesive composition for automobiles>

In order to evaluate the pre-curing properties of the automotive adhesive composition prepared in Examples and Comparative Examples, the following physical properties were evaluated and are shown in Tables 1 to 4 below.

1. Viscosity evaluation

Each of the adhesive composition for automobiles according to Examples and Comparative Examples was put in a container and left in a chamber such that the temperature of the sample was 20±1°C, and the temperature of the sample was kept uniform and stirred to prevent bubbles from entering. Thereafter, the spindle (Spindle NO.7) of the viscometer (DV-I PRIME, BROOKFIELD, U.S.A.) was brought to the center of the sample container, and then deposited to the immersion mark of the spindle. At this time, the number of revolutions of the spindle was set to 2 RPM and rotated for 1 minute 30 seconds, and the measured value was recorded.

2. Specific gravity measurement

First, the specific gravity cup (1127399, BYK, GERMANY) is weighed using a balance (AJ-4200E-C, SHINKO DENSHI, JAPAN), and the vehicle according to Examples and Comparative Examples maintaining a temperature of 20±1℃ 100 ml each of the adhesive composition for the solvent was carefully filled with a specific gravity cup to prevent air bubbles from entering, and the lid was closed. Then, after the sample was wiped out from the hole located in the center of the lid until the sample was not pushed out, the specific gravity cup was placed on the balance to measure the weight, and specific gravity was calculated according to the following equation.

[Mathematics]

3. Flow measurement

Each of the adhesive composition for automobiles according to Examples and Comparative Examples was applied to a steel plate having a thickness of 0.8 mm and a width × height of 75 × 150 mm in an inverted'a' shape with a thickness of 3 mm and a width × length of 50 × 100 mm to measure flowability. In order to fix each test piece at an angle of 70°, the flow after 30 minutes at room temperature was measured. Then, 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 manner.

<Experimental Example 2: After curing the adhesive composition for automobiles>

In order to evaluate the properties after curing of the adhesive composition for automobiles prepared in Examples and Comparative Examples, the following physical properties were evaluated and are shown in Tables 1 to 4 below.

1. Shear strength measurement

Each of the adhesive composition for automobiles according to Examples and Comparative Examples on a steel plate having a thickness of 0.8 mm and a width and a height of 25 × 150 mm is 0.2 mm in thickness and 25 × 12.5 mm in width and width, respectively, and a thickness is applied using a glass bead. After aligning, 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, the shear strength was measured by applying a tensile load at a speed of 5 mm/min and 180° in a universal test machine (ZWICK-Z50, GERMANY).

2. Water resistance (shear) measurement

Each of the adhesive composition for automobiles according to Examples and Comparative Examples on a steel plate having a thickness of 0.8 mm and a width and a height of 25 × 150 mm is 0.2 mm in thickness and 25 × 12.5 mm in width and width, respectively, and a thickness is applied using a glass bead. After aligning, 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, after exposure to water at 40° C. for 168 hours, it was left at room temperature for 30 minutes, and at a speed of 5 mm/min at a universal test machine (Universal test machine, ZWICK-Z50, GERMANY), a tensile load was applied in the direction of 180°. Water resistance (shear) was measured.

3. Measurement of T peel strength

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples on two steel plates having a thickness of 0.8 mm and a width and a height of 25 × 150 mm is 0.2 mm in thickness and 25 × 100 mm in width and width, and glass beads are used. After fixing 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, open the joints without hardened material at 180° and fix each to the clamp part of the universal test machine (ZWICK-Z50, GERMANY), and apply a tensile load in the direction of 180° at a speed of 50 mm/min. Added. At this time, the T peel strength value was averaged from the load-displacement curve in the tensile tester.

4. Impact strength measurement

Each of the adhesive compositions for automobiles according to Examples and Comparative Examples on two bending specimens having a thickness of 1.6 mm and a width × length of 20 × 90 mm, each having a thickness of 0.2 mm and a width × length of 20 × 30 mm, but using a glass bead After using, the thickness of 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. Then, each specimen was impacted using a shock tester (CEAST9350, INSTRON, U.S.A.) under the conditions of 45 kg in weight, 0.2 m in height, and 2 m/s in speed. At this time, the impact strength value was recorded as the impact strength value of the average load of the point at which the peak is 25% from the starting point (time point) and the point at which it is 10% from the end point.

5. Fracture mode Coagulation failure (CF) ratio measurement

Each of the adhesive composition for automobiles according to Examples and Comparative Examples on a steel plate having a thickness of 0.8 mm and a width and a height of 25 × 150 mm is 0.2 mm in thickness and 25 × 12.5 mm in width and width, respectively, and a thickness is applied using a glass bead. After aligning, 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, the shear strength was measured by applying a tensile load at a speed of 5 mm/min and 180° in a universal test machine (ZWICK-Z50, GERMANY). And, there are three types of interface failure (Adhesion Failure, AF or Interfacial Failure, IF) of adhesive and adherend, cohesive failure (CF) in which adhesive itself is destroyed, and substrate failure (SF). The ratio of cohesive failure (CF) in the failure mode was measured.

6. Elongation measurement

Each of the adhesive composition for automobiles according to Examples and Comparative Examples was applied to a dumbbell-shaped tensile specimen frame having a thickness of 3 mm, a width × length of 20 × 160 mm, and a curing agent was cured at 180° C. for 28 minutes using a hot air oven. After standing at room temperature for 1 hour. Then, each tensile specimen was separated to mark the specimen's mark distance according to the specifications, and fixed to the clamp portions of both universal test machines (ZWICK-Z50, GERMANY) of the specimen. Thereafter, a load was applied at a tensile speed of 50 mm/min to measure the elongation at break.

division Example
One Example
2 Example
3 Example
4 Example
5 Example 6 1st epoxy
Suzy Viscosity
(cps, 25℃) 12,500 11,500 13,500 12,500 12,500 12,500 2nd epoxy
Suzy Viscosity
(cps, 30℃) 110,000 110,000 110,000 80,000 140,000 200,000 Third Epoxy
Suzy Viscosity
(cps, 25℃) 650 650 650 650 650 650 Condition (1) (a+b) ^1/2 /c 0.54 0.54 0.54 0.47 0.6 0.71 Condition (2) b/a 8.8 9.6 8.1 6.4 8.8 16 1st and 2nd epoxy resin weight ratio 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1st and 3rd epoxy resin weight ratio 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Curing agent content (parts by weight) 6 6 6 6 6 6 Viscosity modifier content (parts by weight) 6 6 6 6 6 6 Properties before curing Viscosity (Pa·s, 20℃) 15,000 14,700 15,300 10,500 19,500 24,500 importance 1.2 1.2 1.2 1.1 1.2 1.3 Flowability (mm) 2.5 2.5 2.5 2.8 2.5 2.4 Properties after curing Shear strength (Mpa) 21 20 20 21 21 20 Water resistance (shear, Mpa) 21 20 20 21 21 20 T Peeling Strength (N/25mm) 250 250 250 245 250 250 Impact strength (N/mm) 30 30 30 30 30 28 Destruction mode (%, CF) 90 90 90 90 89 79 Elongation (%) 5.1 5.1 5.1 5.1 5 4.2

division Example
7 Example
8 Example
9 Example
10 Example
11 Example
12 1st epoxy
Suzy Viscosity (cps, 25℃) 12,500 12,500 12,500 12,500 12,500 12,500 2nd epoxy
Suzy Viscosity (cps, 30℃) 110,000 110,000 110,000 110,000 110,000 110,000 Third Epoxy
Suzy Viscosity (cps, 25℃) 150 400 900 650 650 650 Condition (1) (a+b) ^1/2 /c 2.33 0.88 0.39 0.54 0.54 0.54 Condition (2) b/a 8.8 8.8 8.8 8.8 8.8 8.8 1st and 2nd epoxy resin weight ratio 1:1.15 1:1.15 1:1.15 1:0.5 1:2 1:1.15 1st and 3rd epoxy resin weight ratio 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 1:0.01 Curing agent content (parts by weight) 6 6 6 6 6 6 Viscosity modifier content (parts by weight) 6 6 6 6 6 6 Properties before curing Viscosity (Pa·s, 20℃) 13,500 14,200 15,700 9,500 21,000 24,000 importance 1.2 1.2 1.2 1.1 1.3 1.2 Flowability (mm) 2.5 2.5 2.5 3.2 2.8 2.7 Properties after curing Shear strength (Mpa) 21 21 21 21 14 20 Water resistance (shear, Mpa) 18 20 21 21 14 20 T Peeling Strength (N/25mm) 194 241 242 248 249 224 Impact strength (N/mm) 30 30 30 21 29 20 Destruction mode (%, CF) 90 90 90 90 90 79 Elongation (%) 5.1 5.1 5.1 2.8 4.8 2.9

division Example
13 Example
14 Example
15 Example
16 Example
17 Comparative example
One 1st epoxy
Suzy Viscosity (cps, 25℃) 12,500 12,500 12,500 12,500 12,500 3000 2nd epoxy
Suzy Viscosity (cps, 30℃) 110,000 110,000 110,000 110,000 110,000 65,500 Third Epoxy
Suzy Viscosity (cps, 25℃) 650 650 650 650 650 980 Condition (1) (a+b) ^1/2 /c 0.54 0.54 0.54 0.54 0.54 0.267 Condition (2) b/a 8.8 8.8 8.8 8.8 8.8 21.8 1st and 2nd epoxy resin weight ratio 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1:1.15 1st and 3rd epoxy resin weight ratio 1:0.5 1:0.15 1:0.15 1:0.15 1:0.15 1:0.15 Curing agent content (parts by weight) 6 One 15 6 6 6 Viscosity modifier content (parts by weight) 6 6 6 0.5 12 6 Properties before curing Viscosity (Pa·s, 20℃) 6,500 14,500 16,000 9,000 26,000 13,200 importance 1.2 1.2 1.2 1.2 1.2 1.2 Flowability (mm) 3.7 3.9 2.5 4.8 2.4 3.7 Properties after curing Shear strength (Mpa) 15 14 20 20 19 14 Water resistance (shear, Mpa) 14 14 20 19 19 14 T Peeling Strength (N/25mm) 239 193 248 251 235 210 Impact strength (N/mm) 28 21 22 29 30 29 Destruction mode (%, CF) 90 90 88 89 89 97 Elongation (%) 4.9 5.2 2.2 4.8 1.9 5.0

division Comparative example
2 Comparative example
3 Comparative example
4 Comparative example
5 Comparative example
6 Comparative example
7 1st epoxy
Suzy Viscosity (cps, 25℃) 20,000 12,500 12,500 - 12,500 12,500 2nd epoxy
Suzy Viscosity (cps, 30℃) 75,000 40,000 110,000 110,000 - 110,000 Third Epoxy
Suzy Viscosity (cps, 25℃) 650 950 1,500 650 650 - Condition (1) (a+b) ^1/2 /c 0.42 0.24 0.23 0.51 0.17 - Condition (2) b/a 3.75 3.2 8.8 - - 8.8 1st and 2nd epoxy resin weight ratio 1:1.15 1:1.15 1:1.15 - - 1:1.15 1st and 3rd epoxy resin weight ratio 1:0.15 1:0.15 1:0.15 - 1:0.15 - Curing agent content (parts by weight) 6 6 6 6 6 6 Viscosity modifier content (parts by weight) 6 6 6 6 6 6 Properties before curing Viscosity (Pa·s, 20℃) 8,300 6,300 23,900 26,000 5,000 28,000 importance 1.2 1.2 1.2 1.2 1.1 1.2 Flowability (mm) 3.1 6.1 2.7 2.6 6.6 2.5 Properties after curing Shear strength (Mpa) 13 19 19 10 20 20 Water resistance (shear, Mpa) 13 19 16 9 20 20 T Peeling Strength (N/25mm) 233 239 186 243 244 249 Impact strength (N/mm) 18 19 27 30 14 19 Destruction mode (%, CF) 88 89 88 90 90 77 Elongation (%) 2.7 2.9 4.3 5 2.1 1.6

As can be seen from Tables 1 to 4 above,

Examples 1 to 5, 8, and 9 satisfying the viscosity and weight ratios of each of the first epoxy resin, the second epoxy resin, and the third epoxy resin according to the present invention, the content of the curing agent and the content of the viscosity modifier, etc. Compared to Examples 6, 7, 10 to 17, and Comparative Examples 1 to 7, which were missing rado, the flowability was low and the composition did not flow, and the ratio of cohesive failure was high. Shear strength, water resistance, T peel strength, impact strength and elongation All of these were 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 to understand the spirit of the present invention may add elements within the scope of the same spirit. However, other embodiments may be easily proposed by changing, deleting, adding, or the like, but this will also be considered to be within the scope of the present invention.

Claims (10)

The first epoxy resin, bisphenol A-type epoxy resin, urethane-modified epoxy resin and CTBN (Carboxyl Terminated Butadiene Acrylonitrile) modified epoxy resin of at least one selected from the second epoxy resin and dimer acid-modified epoxy resin third epoxy resin 1 : 0.8 ~ 1.5: subject resin provided in a weight ratio of 0.05 to 0.3; And
Curing agent; and
The first epoxy resin, the second epoxy resin and the third epoxy resin satisfy the following condition (1) and condition (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, and the third epoxy resin has a viscosity of 300 to 1000 cps at 25°C. Adhesive composition:
(One)

(2)

At this time, the a is the viscosity of the first epoxy resin at 25 ℃ (cps), b is the viscosity of the second epoxy resin at 30 ℃ (cps) and c is the viscosity of the third epoxy resin at 25 ℃ (cps) Indicates. According to claim 1,
The first epoxy resin, the second epoxy resin and the third epoxy resin automotive adhesive composition that satisfies the following conditions (1) and (2):
(One)

(2)

being. delete delete delete According to claim 1,
The second epoxy resin is urethane-modified epoxy resin and CTBN-modified epoxy resin automotive adhesive composition comprising a weight ratio of 1: 0.05 to 0.3. According to claim 1,
The adhesive composition for automobiles comprising 3 to 12 parts by weight of the curing agent, and 0.3 to 3 parts by weight of the curing accelerator with respect to 100 parts by weight of the main resin. According to claim 1,
An adhesive composition for automobiles further comprising 14 to 35 parts by weight of a calcium compound with respect to 100 parts by weight of the main resin. According to claim 1,
An adhesive composition for automobiles further comprising 0.3 to 3 parts by weight of a physical property enhancer for improving peel strength with respect to 100 parts by weight of the main resin. According to claim 1,
The adhesive composition for automobiles further comprising 1.5 to 10 parts by weight of a viscosity modifier with respect to 100 parts by weight of the main resin.