KR101806739B1 - Composition for Tape Type Structural Adhesive - Google Patents

Abstract

The present invention relates to an adhesive composition of a tape-type structure and, more specifically, to an adhesive composition of a tape-type structure including a resin portion having an epoxy resin and a core-shell resin, a curing agent portion, and an additive portion for a common adhesive. The adhesive of the present invention is excellent in workability at a low temperature and a high temperature, a shear adhesive force, and an impact peel strength, and therefore is conveniently used for fastening components in a wide range of industrial fields including automobiles, aircraft, ships, space, civil engineering, and construction.

Description

TECHNICAL FIELD [0001] The present invention relates to a tape-shaped structural adhesive composition,

The present invention relates to a tape-form structural adhesive composition, and more particularly, to a tape-form structural adhesive composition comprising a resin portion containing an epoxy resin having a specific composition and a curing agent portion.

Structural Adhesive is a material used to bond two structures such as wood, composites or metals. Structural adhesives are a traditional mechanical fastening technique that has better force distribution than riveting or welding. Also, the use of adhesive bonding has the advantage of faster working speed. As a mechanical fastening technique, welding is a time-consuming and costly process. Hundreds of spot welds are required in a typical automobile assembly line, and since the selection of welding materials is limited, It is recommended to reduce the number of welds for specific areas. Particularly, in the transportation industry such as automobile, airplane or ship, it is advantageous to use a structural adhesive rather than a mechanical fastening technique to reduce weight.

 The structural adhesive increases the adhesion between the vehicle body, minimizes plastic deformation such as flaring at the time of impact, strengthens the strength to reduce spot welding, and has excellent water tightness. In the automotive sector, structural adhesives are applied to weld seams, weld flanges, and hem flanges.

Structural adhesives applied to the automotive field require impact-resistant and crack-free performance under conditions that can be experienced in the event of an accident such as a vehicle collision. Also, it is required to have a property to maintain excellent physical properties such as workability, adhesive force and impact peel strength even in a temperature range (-40 ° C to 80 ° C) which is wider than a temperature that can be commonly experienced.

General structural adhesives mainly consist of a resin part and a curing agent part. As the main resin constituting the resin part, three kinds of epoxy, polyurethane and acrylic are known.

In addition, general structural adhesives can be classified into paste type adhesives and tape type adhesives by product type. Tape adhesives may be used more advantageously than paste-type adhesives in the bonding of various types of materials, particularly metals, and metals and composites. In particular, when performing structural bonding in addition to laser welding in order to obtain a high adhesive effect, the paste type adhesive can not be used at the welded portion. Therefore, in contrast to the paste type adhesive, the tape type adhesive has an advantage that it is widely used and convenient to apply.

International Patent Publication No. WO 2009-124709, "Improvement in structural adhesives or improvements associated with structural adhesives" International Patent Publication No. WO 2011-033002, "Structural Adhesive Composition"

It is an object of the present invention to provide a tape-form structural adhesive composition which maintains excellent physical properties such as workability, adhesive force and impact peel strength in a wide temperature range of -40 캜 to 80 캜.

In order to solve the above problems, the present invention provides a tape-shaped structural adhesive composition comprising a resin part and a hardener part,

(1) 33 to 50% by weight of a liquid epoxy resin having a viscosity at 23 DEG C of 5,000 to 15,000 cps and an epoxy equivalent of 150 to 300 g / eq;

(2) 15 to 20% by weight of a solid epoxy resin having an epoxy equivalent of 400 to 480 g / eq;

(3) 25 to 40% by weight of a rubber-modified epoxy resin;

(4) 5 to 10% by weight of a urethane-modified epoxy resin; And

(5) 1 to 8% by weight of a core-shell resin in which the acrylic resin surrounds the rubber particle surface; By weight based on the total weight of the resin component.

The tape-like structural adhesive composition of the present invention further comprises 0.5 to 3.0 parts by weight of acicular alumina having an Aspect Ratio of 50 to 100 as a filler based on 100 parts by weight of the resin component. .

The resin part of the tape-form structural adhesive composition of the present invention is characterized by containing a liquid epoxy resin and a solid epoxy resin in a weight ratio of 1.5 to 2.5: 1.

The tape-like structural adhesive composition of the present invention is excellent in properties such as workability, adhesive strength and impact peel strength in a wide temperature range of -40 ° C to 80 ° C, and thus can be suitably applied to automobile, aircraft, And the like.

The structural adhesive composition of the present invention can be used as a tape type adhesive in a place where conventional paste type adhesives are difficult to apply, for example, in a narrow space (e.g., CTR FLR SIDE MBR) And the panel joining step is large, so that it can be easily applied to a part having a problem in flowability, a laser welding part, or the like. In addition, the tape-form structural adhesive composition of the present invention is superior to past past type adhesives in physical properties such as adhesive strength and impact peel strength.

 Hereinafter, the present invention will be described in more detail.

The present invention relates to a tape-type structural adhesive composition exhibiting excellent workability, adhesive strength, impact peel strength and the like in a wide temperature range (-40 ° C to 80 ° C).

The tape-like structural adhesive composition of the present invention largely comprises a resin part and a curing agent part. The resin part is composed of a resin component, a filler, and usual additives.

The tape-like structural adhesive composition of the present invention is characterized by the composition of the resin component constituting the resin part, and also characterized by including needle-shaped alumina together with the resin component as a filler.

First, the composition of the resin component constituting the resin portion of the tape-form structural adhesive composition of the present invention will be described in detail.

The resin component constituting the tape-form structural adhesive composition of the present invention comprises (1) 33 to 50% by weight of a liquid epoxy resin, (2) 15 to 20% by weight of a solid epoxy resin, (3) , (4) 5 to 10% by weight of a urethane-modified epoxy resin, and (5) 1 to 8% by weight of a core-shell resin.

That is, the tape-type structural adhesive composition of the present invention comprises an epoxy-based resin and a core-shell resin as a resin component.

The 'epoxy resin' in the present invention may be a monomeric, oligomeric or polymeric epoxy material comprising at least one epoxy functional group. Representative epoxy resins may include bisphenol A resins and bisphenol F resins as phenolic resins. The molecular weight of the epoxy resin is in the range of 100 to 50,000 g / mol. The epoxy resin having a small molecular weight may be a liquid at room temperature (23 DEG C) or the epoxy resin having a large molecular weight may be a solid at room temperature (23 DEG C).

In the present invention, a liquid epoxy resin present as a liquid at room temperature (23 DEG C) is used as the epoxy resin together with a solid epoxy resin present as a solid.

As the liquid epoxy resin, a bisphenol A resin having a viscosity at a room temperature (23 ° C) of 5,000 to 15,000 cps, a molecular weight of 100 to 900 g / mol and an epoxy equivalent of 150 to 300 g / eq may be used. As the solid epoxy resin, a bisphenol A resin having a melting point of 50 to 80 占 폚, a molecular weight of 15,000 to 50,000 g / mol and an epoxy equivalent of 400 to 480 g / eq may be used. That is, the liquid epoxy resin has a small molecular weight and a small epoxy equivalent as compared with the solid epoxy resin, and thus has a viscosity at room temperature. In the present invention, such a liquid epoxy resin is used in an excess amount of 1: 1.5 ~ 2.5 by weight based on the weight of the solid epoxy resin, and the effect of improving the shear adhesive force and impact peel strength of the adhesive through controlling the weight ratio therebetween is obtained.

Specifically, the resin component may contain the liquid epoxy resin in an amount of 33 to 50 wt%, and the solid epoxy resin may be contained in the content of 15 to 20 wt%. When the content of the liquid epoxy resin contained in the resin component is less than 33% by weight, the content of the solid epoxy resin is relatively increased, and the effect of improving the shear adhesion and impact peel strength can not be expected. If the content of the liquid epoxy resin contained in the resin component exceeds 50% by weight and is used in excess, the content of the solid epoxy resin may be relatively decreased, which may make it difficult to maintain the tape shape. Therefore, in constituting the adhesive composition for a tape-shaped structure of the present invention, it may be important to control the content of the liquid epoxy resin and the solid epoxy resin.

Further, in the present invention, a modified epoxy resin is included as a resin component, and specifically, a rubber-modified epoxy resin and a urethane-modified epoxy resin are used together.

The rubber-modified epoxy resin and the urethane-modified epoxy resin are included to reinforce the impact peel strength expected to be contained in the liquid epoxy resin and to improve the workability. The rubber-modified epoxy resin refers to a resin to which a conjugated diene rubber or a conjugated diene rubber substituted with a carboxylic acid is bonded to an epoxy terminal. For example, a conjugated diene rubber such as styrene, isoprene, butadiene, styrene-butadiene rubber (SBR), or an epoxy resin having a terminal-bonded butadiene rubber (CTBN) substituted with a carboxylic acid may be included. The rubber-modified epoxy resin may have a viscosity of approximately 4000 to 7000 cps.

In the resin component of the present invention, the rubber-modified epoxy resin may be contained in an amount of 25 to 40 wt%, and the urethane-modified epoxy resin may be contained in an amount of 5 to 10 wt%. If the content of the rubber-modified epoxy resin or the urethane-modified epoxy resin contained in the resin component is less than the above range, the effect of reinforcing the impact peel strength and improving the workability can not be expected. The impact peel strength may be excellent, but there may be a problem that the shear adhesive force is relatively lowered.

The present invention also includes a core-shell resin as a resin component. The core-shell resin may be composed of an elastic core polymer and a hard shell polymer. That is, a resin in which elastic rubber particles are present as a core and a surface of the rubber particles is surrounded by a hard acrylic resin to form a shell forms a core-shell structure can be used. Specifically, butadiene rubber particles or styrene-butadiene rubber particles can be used as the core material, and polymethyl methacrylate (PMMA) or acrylonitrile (AN) can be used as the shell material. The core-shell resin absorbs the impact of the rubber core during an external impact, thereby enhancing the shape-retaining effect and enhancing the impact strength.

In the resin component of the present invention, the core-shell resin may be included in the range of 1 to 8 wt%. If the content of the core-shell resin contained in the resin component is less than 1% by weight, the effect of reinforcing the impact peel strength at low temperatures may be insufficient. If the content is in excess of the above range, the impact peel strength is excellent However, there is a problem that the shear adhesive force is relatively lowered.

In addition, the resin part of the tape-form structural adhesive composition of the present invention may contain fillers and usual adhesive additives in addition to the resin components.

The filler may be any material that does not react with other components contained in the adhesive composition. For example, fillers commonly used in the production of adhesive compositions such as silica, alumina, diatomaceous earth, glass, clay, talc, carbon, and ceramic fibers may be included.

Preferably, it may include needle-shaped alumina as a filler. Specifically, needle-shaped alumina having an aspect ratio (aspect ratio) of 50 to 100, which shows a length / diameter ratio, can be used as a filler. Since the needle-shaped alumina is arranged and arranged in a horizontal direction in the structure, resistance to impact can be expected to be improved.

The filler may be included in the range of 15 to 30 parts by weight per 100 parts by weight of the resin component. The needle-shaped alumina may have a sufficient impact strength reinforcing effect even when a small amount of the filler is used together with a conventional filler.

As the usual additives, a water absorbent, a flow inhibitor, a rubber modified low viscosity epoxy, a heat stabilizer and the like may be included.

The water absorbent absorbs moisture contained in the material to suppress the generation of bubbles during curing due to moisture contained in the filler when the filler is mixed with the epoxy resin, thereby improving the strength. Such a water-absorbing agent may include, for example, a silica-based water-absorbing agent. The content of the water absorbent may be appropriately controlled within a range of 1 to 10% by weight based on 100 parts by weight of the resin component.

The flow inhibitor prevents some of the components in the adhesive composition from sinking to prevent phase separation of the product during storage and movement. Such flow inhibitors may include, for example, silica butyl phthalate and the like. The content of the flow inhibitor may be appropriately controlled within a range of 5 to 20% by weight based on 100 parts by weight of the resin component.

The rubber modified low viscosity epoxy may be used to impart a solid phase shape and to complement the adhesive strength enhancement. Such a rubber-modified low-viscosity epoxy refers to a resin to which a conjugated diene rubber or a conjugated diene rubber substituted with a carboxylic acid is bonded to an epoxy terminal. For example, a conjugated diene rubber such as styrene, isoprene, butadiene, styrene-butadiene rubber (SBR), or an epoxy resin having a terminal-bonded butadiene rubber (CTBN) substituted with a carboxylic acid may be included. The rubber-modified low viscosity epoxy may have a viscosity in the range of 2000 to 3500 cps. The content of the rubber-modified low-viscosity epoxy may be suitably controlled within a range of 0.1 to 5% by weight based on 100 parts by weight of the resin component.

The heat stabilizer can be used to impart heat stability. Examples of the heat stabilizer include alumina oxide and the like. The content of the heat stabilizer may be appropriately controlled within the range of 0.1 to 5% by weight based on 100 parts by weight of the resin component.

In addition, the tape-form structural adhesive composition of the present invention includes a curing agent portion containing at least one curing agent capable of crosslinking an epoxy resin.

The curing agent may typically include an amine curing agent or an amide curing agent. The amine curing agent may include an aliphatic or aromatic amine compound having an -NH- group, and the amide curing agent may include an amide compound. The amine curing agent may be, for example, ethylene diamine, diethylene diamine, diethylene triamine, triethylene tetramine, propylene diamine, tetraethylene pentamine, hexaethylene heptamine, hexamethylene diamine, , 5-pentamethylene-diamine, 4,7,10-trioxatridecane-1,13-diamine, aminoethylpiperazine, and the like. The amide curing agent may include dicyandiamide and the like.

The content of the curing agent may be 20 to 40 parts by weight based on 100 parts by weight of the resin component.

In addition, a curing accelerator may be included together with the curing agent for the purpose of promoting curing at a low temperature. The curing accelerator may include imidazole and the like and may be used in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the resin component.

The adhesive composition described above can be fastened by applying between two parts to be fastened and curing the adhesive to form a joint. The substrate to which the adhesive of the present invention can be applied includes a metal such as steel, iron, copper, and aluminum and an alloy thereof, and may include carbon fiber, glass fiber, glass, epoxy fiber composite material, wood and the like. And can therefore be conveniently used as structural adhesives in processes for fastening components in a wide range of industries, including automotive, aircraft, marine, aerospace, civil engineering, and construction.

The present invention will now be described in more detail with reference to the following examples, but the present invention is not limited thereto.

[Example]

Examples 1 to 6 and Comparative Examples 1 to 8. Preparation of Tape Type Structural Adhesive

The adhesive compositions were prepared by blending the composition components and the composition ratios shown in Tables 1 and 2 below. That is, a resin component comprising a liquid epoxy resin, a solid epoxy resin, a rubber-modified epoxy resin, a urethane-modified epoxy resin and a core-shell resin was placed in an electric oven and stirred at 110 ° C for complete melt mixing. The molten mixture was placed in a blender, stirred while being filled with a filler, and dispersed evenly. Then, an additive and a curing agent were added and stirred to prepare an adhesive.

Then, when the produced adhesive came out through the roller, a releasing paper was attached to the surface of the adhesive to prepare a tape-like structural adhesive.

[Ingredients Used]

(1) Liquid epoxy resin: bisphenol A epoxy resin having a viscosity at 23 캜 of 9,000 cps, a molecular weight of 500 g / mol and an epoxy equivalent of 210 g / eq

(2) Solid epoxy resin: Bisphenol A epoxy resin having a molecular weight of 30,000 g / mol and an epoxy equivalent of 440 g / eq

(3) Rubber-modified epoxy resin: an epoxy resin having a butadiene rubber bonded to its end, a viscosity of 5,000 cps

(4) Urethane modified epoxy resin

(5) Core-shell resin: The core-shell resin in which the acrylonitrile resin surrounds the surface of the butadiene rubber particles

(6) Filler:

  ① Carbon: Spherical carbon

  ② spherical alumina: spherical alumina

  (3) Needle-like alumina: Needle-like alumina having an aspect ratio of 50 to 100

(7) Additive:

  ① Water absorbent: Silica absorbent

  ② Flow inhibitor: Silica butyl phthalate

  ③ Rubber modified low viscosity epoxy: Epoxy resin with butadiene rubber bonded at the end, viscosity 3,000 cps

  ④ Heat stabilizer: Alumina oxide

(8) Hardener: Amide hardener

division Example One 2 3 4 5 6 Suzy
(weight%) Liquid epoxy resin 38 38 38 38 38 38 Solid epoxy resin 18 18 18 18 18 18 Rubber-modified epoxy 31 31 31 31 31 31 Urethane-modified epoxy 9 9 9 10 9 7 Core shell resin 4 4 4 3 4 6 Filler
(Parts by weight) Carbon 11 11 11 11 11 11 Spherical alumina 9 9 9 9 9 9 Acicular alumina 0.8 1.5 2.5 0 0 0 additive
(Parts by weight) Water absorbent 3.5 3.5 3.5 3.5 3.5 3.5 Flow inhibitor 6.5 6.5 6.5 6.5 6.5 6.5 Rubber modified low viscosity epoxy 2 2 2 2 2 2 Heat stabilizer 1.8 1.8 1.8 1.8 1.8 1.8 Curing agent (parts by weight) 30 30 30 30 30 30  Weight part: Represents the content of filler, additive or hardener based on 100 parts by weight of resin

division Comparative Example existing
(PASTE type) One 2 3 4 5 6 7 8

Suzy
(weight%) Liquid epoxy resin 24 24 24 24 24 30 38 42 24 Solid epoxy resin 12 15 18 21 25 18 18 14 0 Rubber-modified epoxy 51 48 45 42 38 35 31 31 63 Urethane-modified epoxy 9 9 9 9 9 13 13 9 13 Core shell resin 4 4 4 4 4 0 0 4 0
Filler
(Parts by weight) Carbon 11 11 11 11 11 11 11 11 11 Spherical alumina 9 9 9 9 9 9 9 9 9 Acicular alumina 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 0
additive
(Parts by weight) Water absorbent 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 Flow inhibitor 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 Rubber modified low viscosity epoxy 2 2 2 2 2 2 2 2 2 Heat stabilizer 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 Curing agent (parts by weight) 30 30 30 30 30 30 30 30 30 Weight part: Represents the content of filler, additive or hardener based on 100 parts by weight of resin

[Experimental Example]

The physical properties of the tape-form structural adhesive prepared in Examples and Comparative Examples 1 to 8 were measured by the following methods, and the results are shown in Tables 3 and 4 below.

(1) Specific gravity: Specific gravity measured value

(2) Intrusion degree: Measured by penetration into the sample for 5 seconds using an intrusion meter with a total load of 200 ± 0.06 gf falling down including the cone and needle.

(3) Hardness: The value measured with a Shore D type hardness meter

(4) Workability: It is judged that steel plate is attached at 5 ℃ in winter, and easiness of removal of release paper at 35 ℃ in summer.

(5) Shear bond strength:

  ① Adhesion at room temperature: Measured at 23 ℃.

  ② High temperature contact force: Measured at 80 ℃.

  ③ Water resistance: Measured after immersing in water at 40 ~ 50 ℃ for 100 ~ 200 hours.

  ④ Aging resistance: Measured after immersing in water at 80 ℃ for 300 ~ 400 hours.

  ⑤ Heat cycle: Heat cycle: 70 ~ 80 ℃ → 20 ~ 25 ℃ → -30 ~ 20 ℃ → 20 ~ 25 ℃ → 40 ~ 50 ℃ → 20 ~ 25 ℃ for one hour, Measured later.

(6) Impact peel strength: Measured using impact impact tester at room temperature (23 ° C), high temperature (80 ° C) and low temperature (-40 ° C)

(7) T-peel strength:

A 20 x 30 mm adhesive prepared on one side of a 90 x 20 x 1.6 mm steel sheet was applied and the steel sheet was bonded to the other side. The joints were fixed with CLIP (compression force: approx. 0.3 kg) and cured at 155 ° C for 23 minutes. After that, the specimens were left for 1 hour under the standard conditions of 22 ° C and relative humidity of 65%. The fabricated specimens were subjected to a tensile load at a tensile speed of 50 mm / min and a direction of 180 degrees using a tensile tester (Zwick / Roell Z050). The T-Peel Strength (N / 25 mm) was recorded from the load-displacement curves of the automatic recorder attached to the tensile tester to a mean value of 50 mm after the initial maximum value.

Evaluation items Requirements Example One 2 3 4 5 6 importance 1.4 or less 1.22 1.22 1.23 1.24 1.24 1.24 Intrusion 40 to 70 62 63 64 64 64 64 Hardness (Hs) 70 ± 10 77 79 78 74 76 80 Workability Winter season Good Good Good Good Good Good Good Summer Good Good Good Good Good Good Good
shear
Adhesion
(MPa) Room temperature
(23 ° C) 25 or more 33.8 34.1 34.2 34.2 33.7 27.0 High temperature
(80 DEG C) 18 or more 24 24.2 24.5 22.9 23.5 24.1 Water resistance 25 or more 31.3 31.8 32.4 31.1 30.8 30.9 Aging resistance 25 or more 31.1 31.6 32.1 32.6 32.8 32.9 HEAT CYCLE 25 or more 35.1 35.6 36.6 33.6 34.4 34.6
Shock
Exfoliation
burglar
(N / mm) Room temperature
(23 ° C) 35 or more 49.7 50.0 49.8 46.2 47.5 48.2 High temperature
(80 DEG C) 30 or more 52.4 52.1 52.4 51.2 51.9 52.5 Low temperature
(-40 ° C) 20 or more 35.3 35.6 36.1 37.6 37.2 38.5 T-peel strength
(N / 25 mm) 250 or more 320 318 316 330 322 314

According to the results shown in Table 3, the adhesive compositions of Examples 1 to 6 satisfied the composition components and the composition ratio ranges proposed by the present invention were excellent in workability at low temperature and high temperature, shear adhesive strength, and impact peel strength. In particular, it is confirmed that the impact peel strength is superior to the conventional paste adhesive in the entire temperature range of high temperature and low temperature.

Examples 1 to 3 and Examples 4 to 6 are adhesives having a difference in the content of needle-like alumina as a filler. In Examples 1 to 3, the shear adhesive force tended to increase as the content of acicular alumina was increased. In contrast to Example 5 in which the acicular alumina was not included, Examples 1 to 3 showed that the acicular alumina It can be confirmed that the shear adhesive strength is improved.

Evaluation items Requirements Comparative Example Paste type
glue One 2 3 4 5 6 7 8 importance 1.4 or less 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.23 Intrusion 40 to 70 58 61 65 69 71 62 66 70 - Hardness (Hs) 70 10 72 75 77 81 84 78 75 72 75 Workability Winter season Good Bad Good Good Good Good Inadequate Good Good - Summer Good Bad Bad Good Good Good Good Good Inadequate -
shear
Adhesion
(MPa) Room temperature
(23 ° C) 25 or more 17.1 18.2 21.7 22.3 21.2 31.5 24.5 37.9 33.5 High temperature
(80 DEG C) 18 or more 16.8 18.1 19.4 21.1 22.8 21.5 22.7 23.9 24.2 Water resistance 25 or more 27.1 29.4 29.4 29.1 29.7 30.2 20.3 31.5 29 Aging resistance 25 or more 24.8 27.3 28.4 29.2 29.9 29.1 29.9 31.2 32.2 HEAT CYCLE 25 or more 30.4 31.1 32.7 34.4 36.7 33.4 34.8 36.2 33.7
Shock
Exfoliation
burglar
(N / mm) Room temperature
(23 ° C) 35 or more 33.5 36.7 40.1 41.8 43.5 33.2 33.6 44.2 42.5 High temperature
(80 DEG C) 30 or more 42.1 45.8 48.7 49.3 51.2 30.1 30.4 50.5 49.8 Low temperature (-40 ℃) 20 or more 31.4 33.8 33.2 32.1 30.7 18.6 19.4 35.1 35.2 T-peel strength
(N / 25 mm) 250 or more 285 295 305 315 325 315 318 321 310

In Comparative Examples 1 to 8, it was confirmed that the adhesive composition deviates from the range proposed by the present invention in terms of the content and the weight ratio of the liquid epoxy resin and the solid epoxy resin. According to Table 4, workability and shear adhesive strength at room temperature are poor have. Particularly, in Comparative Example 5 in which the content of the solid epoxy resin is relatively high in the weight ratio of the liquid phase and the solid phase epoxy resin, it can be confirmed that the shear adhesive strength at room temperature is low.

In addition, in Comparative Examples 6 to 7, it was confirmed that the impact peel strength was poor as an adhesive containing no core-shell resin.

In addition, in Comparative Example 8, the liquid epoxy resin was relatively high in the weight ratio of the liquid epoxy resin to the solid epoxy resin.

Claims (7)

A tape-type structural adhesive composition comprising a resin part and a curing agent part, wherein the resin part
(1) 33 to 50% by weight of a liquid epoxy resin having a viscosity at 23 DEG C of 5,000 to 15,000 cps and an epoxy equivalent of 150 to 300 g / eq;
(2) 15 to 20% by weight of a solid epoxy resin having an epoxy equivalent of 400 to 480 g / eq;
(3) 25 to 40% by weight of a rubber-modified epoxy resin;
(4) 5 to 10% by weight of a urethane-modified epoxy resin; And
(5) 1 to 8% by weight of a core-shell resin in which the acrylic resin surrounds the rubber particle surface,
Wherein the liquid epoxy resin (1) and the solid epoxy resin (2) are contained in a weight ratio of 1.5 to 2.5: 1.
The method according to claim 1,
Wherein the resin part further comprises 0.5 to 3.0 parts by weight of acicular alumina as a filler based on 100 parts by weight of the resin component.
3. The method of claim 2,
Wherein the acicular alumina has an aspect ratio of from 50 to 100.
delete The method according to claim 1,
Wherein the rubber-modified epoxy resin is an epoxy in which a conjugated diene rubber or a conjugated diene rubber substituted with a carboxylic acid is bonded to the terminal.
The method according to claim 1,
Wherein the core-shell resin is a resin in which rubber particles are present as a core and the surface of the rubber particle is surrounded by an acrylic resin to form a shell.
The method according to claim 6,
The core-shell resin is a resin in which butadiene rubber particles or styrene-butadiene rubber particles are present as a core and polymethylmethacrylate (PMMA) or acrylonitrile (AN) resin forms a shell By weight of the adhesive composition.