JPH04142383A - Adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in the balance between the bonding strength and the flexibility and suitable particularly for filling a hemmed part by mixing a liquid epoxy resin, a specified modified polyolefin resin powder, a latent curing agent, and a latent curing agent comprising an amine adduct. CONSTITUTION:100 pts.wt. liquid epoxy resin is mixed with 5-50 pts.wt. modified polyolefin resin powder having a mean particle diameter of about 0.9 to 1.5 times the preset thickness of an adhesive and a melting point of 70-190 deg.C, 1-50 pts.wt. latent curing agent, and 0.5-20 pts.wt. latent curing agent comprising an amine adduct to give the title composition. It can be used in various applications as an adhesive excellent in the balance between the bonding strength and the flexibility. It is excellent particularly as an adhesive for the hemming of an automobile body. It can be utilized also as a sealant, a coating material, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an adhesive composition, and particularly to an adhesive composition suitable for being filled into a hemming portion of an automobile body.

(Prior Art) In recent years, adhesives have been used in everything from daily necessities to buildings, but the performance required of adhesives varies depending on the location where they are used.In some cases, strong adhesive strength is required. ,
There are cases where such strong adhesive force is not required.

Nowadays, machines and equipment are automated by robots, etc., and bonded objects are often subjected to vibrations and shocks after bonding, so they are required to have relatively high shearing force and elasticity, and have adhesive strength and flexibility. Adhesive is required. For example, conventionally, paste-type epoxy resin adhesives are mainly used for areas where it is difficult to apply anti-rust treatment due to the structure of an automobile body, such as door hemmings, hood inner edge hemmings, and rocker panels. is used. That is, as shown in FIG.
Adhesive 3 is applied to the edge of the interior plate 2, and the edge of the interior plate 2 is aligned therewith, and then the edge of the exterior plate 1 is folded back and press-formed to form a bent portion 1a, thereby forming a hemming structure. The panels with the second hemming structure are assembled by spot welding for temporary fixing, and are degreased and cleaned along with the entire vehicle body.
After undergoing chemical conversion treatment such as acid treatment, it is subjected to an electrodeposition coating process, and the adhesive is cured and fixed in a paint baking oven during this process.

However, with conventional paste-like epoxy resin adhesives, the adhesive tends to fall off or scatter during the degreasing, acid treatment, etc., and the processing solution is contaminated, and spot welding for temporary fixing is difficult to avoid dents. This is unfavorable in terms of the appearance of the car body. Furthermore, after conventional epoxy resin adhesives are baked and hardened in the electrodeposition coating process, they are highly rigid and dynamic stress such as vibrations during the car body assembly process or while driving can cause the terminals of the cured epoxy resin adhesive to break down. The electrodeposition coating may peel off from the edge 4a,
There is a problem that cracks form, and water and moisture can enter through the cracks, causing rust.

In addition, from the perspective of resource conservation, there is a great social need to improve the durability of automobiles and extend the lifespan of the car body. It is to protect from The parts mentioned above that are difficult to apply anti-rust treatment to due to the structure of the car body have a bag structure, so if moisture or moisture from rainwater etc. enters, the intruded moisture or moisture tends to accumulate, and from there rust can occur. This will shorten the life of the vehicle. From these points as well, an excellent adhesive is desired.

[Problem to be solved by the invention]

As mentioned above, adhesives in automated factories are required to have adhesive strength and flexibility after curing, and in particular, as adhesives for hemming in automobile assembly processes, (1) adhesives that form hemmed structures by coating and molding are It can be temporarily fixed by means other than spot welding, such as short-term low-temperature preheating, and (2) it does not fall off, scatter, or get stained by the processing solution during degreasing, cleaning, acid treatment, etc. in the next process. (3) Baking in the electrodeposition coating process is required to have sufficient adhesion and flexibility after curing, and (4) to satisfy all of the following requirements: (4) sufficient long-term adhesive durability and rust prevention. There is a high demand for something that can be used in assembly processes that require sufficient adhesion and flexibility not only at room temperature but also at high temperatures. Of course, it goes without saying that it is essential that these also satisfy appropriate viscosity for coating operations, storage stability, fixability to oil-surface steel plates, etc.

As an adhesive that satisfies the above requirements, particularly as a material for an adhesive for a hemming part of an automobile body, an adhesive that can be formed into a pregel by blending a powdered thermoplastic resin with a liquid epoxy resin has been proposed. For example, in JP-A-56-82865, thermoplastic resins include polyethylene/polypropylene copolymers, ethylene/acrylic acid/acrylate ternary copolymers, polyamides, ethyl cellulose, polyvinyl formal, and polyvinyl butyral. Among the above requirements, (1) and (2) may be satisfied, but (3) sufficient adhesive strength, especially peel strength, is not satisfied. Historically, (4) sufficient adhesion strength under high temperatures is not satisfied.9 The present inventors: Well,
Focusing on the ability of modified polycarbonate resin to sufficiently bond steel plates together by short-term low-temperature heating, and providing flexibility,
As a result of intensive research to solve the above problems with an adhesive that satisfies the above requirements, in particular, this pasty epoxy adhesive composition, we have found that liquid epoxy resin, modified polyolefin resin powder with a specific particle size and specific melting point, and latent The inventors have discovered that the above-mentioned problems can be solved with a composition containing a curing agent and a latent amine adduct type curing agent, and have completed the present invention.

[Means for Solving the Problems] According to the present invention, (A) a liquid epoxy resin, (B) having an average particle size of about 0.9 to 1.5 times the set adhesive layer thickness, and having a melting point of 70 ~190°C modified polyolefin resin powder,
An adhesive composition is provided that includes (C) a latent curing agent and (D) a latent amine adduct type curing agent.

As the component (A) liquid epoxy resin of the present invention, a liquid epoxy resin having an average of two or more epoxy groups in the molecule, which is used as a component of ordinary epoxy resin adhesives, is used. Examples of such epoxy resins include bisphenol A epoxy resin, bisphenol F
Examples include type epoxy resins, novolak type epoxy resins, polyfunctional phenol type epoxy resins, and various halogenated epoxy resins. Further, diglycidyl ether compounds obtained by the reaction of redulcinol and epihalohydrin, glycidyl ester type epoxy resins, polyglycol type epoxy resins, cycloaliphatic epoxy resins, hydantoin type epoxy resins, glycidyl amine type epoxy resins, etc. can also be used. . Epoxy resins can be used alone or in combination of two or more.

The component (B) modified polyolefin of the present invention is ethylene,
Homopolymers of olefins such as propylene, random and block copolymers thereof, and copolymers containing some monomers that can be copolymerized with diene (in copolymers, the content of olefins is 40% by weight) Polyolefins such as (the above are preferred) are grafted with a graft monomer having a functional group. Examples of graft monomers include unsaturated carboxylic acids or derivatives thereof; examples of unsaturated carboxylic acids include acrylic acid, maleic acid,
Fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid [
F]
Examples of derivatives thereof include acid halides, amides, imides, anhydrides, and esters. Specifically, they include maleyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl maleate, and the like. Among these, unsaturated dicarboxylic acids or their derivatives are preferred, particularly maleic acid, nadic acid [F
], alkenylsuccinic acids, or acid anhydrides thereof are more preferred.

In addition to the above, acryloylbenzotria' seals and the like can also be used as graft monomers.

Various conventionally known methods can be employed to produce the modified polyolefin by graft copolymerizing the graft monomer with the polyolefin. For example, there is a method in which a polyolefin is melted and a graft monomer is added to perform graft copolymerization, and a method in which a polyolefin is melted in a solvent and a graft monomer is added to perform graft copolymerization.

In any case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the reaction in the presence of a radical initiator. The graft reaction is usually 60
It is carried out at a temperature of ~350°C, and the amount of radical initiator used is usually 0.000 parts by weight per 100 parts by weight of polyolefin. OO
It is in the range of 1 to 1 part by weight.

Examples of the radical initiator include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2.
5-dimethyl-2,5-cy(ver-quinto\onsoate)hexyne-3,1,4-his(jerL-butylperoxyisopropyl)Hensen, lauroyl peroxyproquine, tert-butyl peracetate, 2.5 dimethyl -2,5-di(tert-butylperoxy)hexane-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylverhenzoate, tert-butylperphenyl Acetate, tert-butyl perisobutyrate, tert-butyl per5ec-octoate, tert-butyl pervivalate, cumyl pervivalate and tert-butyl perdiethyl acetate, organic peroquinides and organic peresters, as well as e.g. Examples include azo compounds such as isobutyronitrile and dimethylazoisobutyrate.

Among these, dicumyl peroxide, di-tert-
Butyl peroxide, 2,5-dimethyl-25-di(t
ert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(te'rt-butylperoxy)
Dialkyl peroxides such as hexane, 1,4-bis(tert-butylperoxyisopropyl)-, andne are preferred.

Further, the modified polyolefin of the present invention may be either a block copolymer or a random copolymer obtained by graft copolymerization of a polyolefin and a heptamer having the above functional group as described above.

Furthermore, the modified polyolefin of the present invention has a melting point of 70 to 1
A temperature range of 90°C is used.

If the melting point is less than 70° C., sufficient adhesive strength at high temperatures in accordance with the above requirement (4) cannot be obtained. On the other hand, the melting point is 1
If the temperature exceeds 90'C, the normal baking temperature in the electrodeposition coating process will be higher than the temperature (180'C), and the modified polyolefin in the adhesive composition will not melt in the electrodeposition coating process, so the above requirement (3) is met. Baking results in insufficient adhesion and flexibility after curing.

Furthermore, the modified polyolefin of the present invention has an average particle size of about 0.9 to 1.5 times the thickness of the adhesive layer that is preset to a predetermined thickness using the adhesive composition of the present invention. Use particles in the range of . If the average particle size is less than 0.9 times, the baking in the above requirement (3) will result in insufficient adhesion and flexibility after curing, whereas if it exceeds 1.5 times, baking will occur; The adhesive layer thickness after curing may become too thick or uneven compared to the predetermined thickness.1.
I don't like it.

The amount of the modified polyolefin resin powder used as component (A) of the present invention is preferably 5 to 50 parts by weight per 100 parts by weight of the liquid epoxy resin. If it is less than 5 parts by weight, the above requirements (3
) Baking does not provide sufficient adhesion and flexibility after curing, and if it exceeds 50 parts by weight, the viscosity of the adhesive increases and workability in application etc. decreases, which is undesirable.

As the component (C) latent curing agent used in the present invention, those commonly used as curing agents for epoxy resins are used. For example, guanidine derivatives, triazine derivatives,
Examples include 4,4'-diaminodiphenylsulfone, acid hydrazide compounds, imidazur compounds, N,N'-dialkyl urea derivatives, and N,N'-dialkylthiourea derivatives. The amount of these used is 10% of liquid epoxy resin.
1 to 0 parts by weight. 50 parts by weight, preferably 3-4
It is 0 parts by weight. If it is less than 1 part by weight, curing will be insufficient and no adhesive strength will be developed, and if it exceeds 50 parts by weight, the adhesive will become hard and brittle after being heated and cured.

Component (D) i-based amine adduct-type curing agent used in the present invention is an amine compound that is generally known to react with epoxy resins to form adducts, such as the product name manufactured by Ajinomoto Co., Ltd.: Amicure PN-23. Amicure M'y"-24 and the like are used. The amount of the latent amine adduct type curing agent used is preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight, based on 100 parts by weight of the liquid epoxy resin. If it is less than 1 part by weight, sufficient temporary adhesive strength will not be exhibited. If it exceeds 20 parts by weight, the adhesive will become hard and brittle after being heated and cured.

The adhesive composition of the present invention includes alkaline earth metal carbonates or sulfates such as calcium carbonate, barium carbonate, magnesium carbonate, calcium sulfate, barium sulfate or magnesium sulfate, silica, clay, titanium oxide, aluminum powder, etc. fillers can be blended. The amount used is preferably 10 to 200 parts by weight per 100 parts by weight of the liquid epoxy resin. If the amount is less than 10 parts by weight, the cohesive force of the adhesive after heat curing is insufficient, and if it exceeds 200 parts by weight, the adhesive after heat curing becomes too hard and its flexibility is impaired.

Furthermore, various other additives such as softeners, titanium-imparting agents, etc. can be added to the composition of the present invention. Examples of the softener include various liquid rubbers.

The liquid rubber used is one that does not have a functional group that can react with the liquid epoxy resin at room temperature in order to ensure storage stability of the viscosity of the adhesive composition. Examples of titanium-imparting agents include fine silica, organic bentonite, and ultrafine calcium carbonate. Further, when the adhesive composition contains water, it is also possible to add and mix a relatively small amount of powder such as calcium oxide, mag2sium oxide, silicon oxide, etc. as a water adsorbent.

Furthermore, colorants such as carbon black and hengara can be optionally added.

The adhesive composition according to the present invention can be obtained by kneading the above-mentioned components using a kneading machine typified by a two-coul mixer, a two-dough mixer, a paddle mixer, a plastic terry mixer, a disper mixer, etc., by conventional means.

The composition of the present invention can be used for various purposes as an adhesive with an excellent balance between adhesive strength and flexibility, and is particularly excellent as an adhesive for hemming automobile bodies in the automobile industry. In addition to being used as an adhesive, it can also be used in various industrial applications such as sealants and paints.

[Effects of the Invention] The composition of the present invention has the following advantages: (1) A panel with a hemmed structure formed by coating and molding can be bonded to a hemmed structure without the need for spont welding for temporary fixing, and with sufficient adhesion strength especially by short-term low-temperature preheating. (2) No falling off, scattering, or contamination of the processing solution during the next process of degreasing, cleaning, acid treatment, etc. (3) Baking is possible after curing, especially not only at room temperature but also at high temperatures. It has sufficient adhesion strength and flexibility, and satisfies all of (4) sufficient adhesion durability and rust prevention, making it an extremely useful adhesive for industrial applications. Suitable as a dressing agent.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

However, the present invention is not limited to the following examples.

The test and evaluation method was as follows.

(Storage stability viscosity of 11 viscosity was determined using a capillary extrusion viscometer at 35°C and a shear rate of 62
The value was taken as 5ec-'. Storage stability was evaluated as O if the viscosity change rate was within 30% after holding the adhesive composition at 40'C for 7 days, and × if it exceeded 30%.

(2) Adhesive strength Using oiled steel plate (SPC-D @ plate) coated with anti-rust oil, heat cure at 150'C for 10 minutes and at 170'C for 20 minutes to determine shear adhesive strength and peel adhesion. JI power each
23℃ according to S K6850 and JIS K6854
It was measured with The adhesive layer thickness was 150 pm. 15
The adhesion strength when cured for 0'CIO minutes is used as a guideline for 1 retardation property.Also, the adhesive strength under high temperature is determined by curing at 170℃ for 20 minutes. The force was measured.

(3) After applying flexible adhesive to an oil surface steel plate in the shape of 150 x 25 x j'mm, heat harden it at 170'C for 20 minutes, and bend the steel plate at a 45° angle using a 1 inch diameter mandrel at room temperature. let In this case, the case where the cured adhesive layer did not crack was marked as ○, and the case where it cracked was marked as ×.

(4) Adhesive durability Test piece heat cured at 170°C for 20 minutes in (2) above at 50°C.
After being held at 195% RH for 30 days, the adhesive strength was measured at 23°C, and a case where the strength was 80% or more of the initial strength was rated as ○, and a case where it was less than 80% was rated as ×.

(5) Rust prevention After applying the adhesive of the present invention to the lower part of the exterior plate ■ at the hemming part O of the automobile body shown in Figures 1 and 2, press the interior machine 2 against it, and then , 1 was bent and caulked. Then heat this at 150℃ for 10
After curing the adhesive by heating for a minute, the protruding portion from the edge 2a toward the interior panel was removed and electrocoated. The baking conditions were 170°C for 20 minutes. The hemming model thus obtained was subjected to a rust prevention test. Rust resistance is 50
One cycle is immersed in a 5% NaCl aqueous solution for 4 hours at 80°C, air-dried for 2 hours at 80°C, and left at room temperature for 2 hours. The case where the occurrence of O1 was slight and the case where O1 was significant were marked as ×.

Examples 1 to 6 and Comparative Examples 1 to 6 Predetermined parts by weight of the raw materials shown in Table 1 were placed in a planetary mixer, kneaded, and defoamed to obtain adhesive compositions. Table 2 shows the various test results of the obtained adhesive composition.

As shown in Table 2, the adhesive composition of the present invention shown in the Examples satisfies the characteristics required for a hemming adhesive,
In particular, it not only has high adhesive strength even when cured at low temperatures, but also has high peel strength even during main curing at 170°C for 20 minutes.It also has high adhesive strength at high temperatures. or 6 years old was approved.

The physical properties of the main raw materials shown in Table 1 were as follows.

(+) O5-resin lPtl-22G epoxy equivalent;
270-310 Viscosity (25°C, psl): 1-2 (2) Epicron TS [l-960 (rubber modified epoxy resin) Epoxy equivalent = 232 Viscosity (25°C, ps): 610 (3) Hycar @ CTBN 1300X13 ( Contains carnexy groups at both ends? Acrylonitrile bond amount (χ): 27 Viscosity (27°C 1 ps): 6250 (4) TX-171 (maleated propylene/ethylene fluoride polymer powder) Specific gravity: 0.895 Melting point = 160°C Average particle size: L'a5um 5] NS 101 tMaleinated linear (livestock-modified polyester powder) Specific gravity: O9 3 Melting temperature: 120°C Average particle size: 180μm f6 ) IJ-25H maleated linear I density polyethylene powder) Specific gravity: 0.93 Melting point: 120'C Average particle size: 120 μm (7) Nibol 1312 (jffl-shaped futazen-7
Krylo = January Recom) 7 Crylonitrile bond amount (X)
:33.5 Viscosity (30℃, ps): 1000 (Hereafter, margin)

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the structure of an automobile body hemming part using the adhesive of the present invention, and FIG. 2 is a perspective view thereof. ■...Exterior plate 1a...Bending part 2...
・Interior board 2a...Edge 3...Adhesive

Claims (3)

[Claims] (1) (A) liquid epoxy resin, (B) has an average particle size of about 0.9 to 1.5 times the set adhesive layer thickness, and has a melting point of 7
An adhesive composition comprising a modified polyolefin resin powder having a temperature of 0 to 190°C, (C) a latent curing agent, and (D) a latent amine adduct type curing agent. (2) (A) 100 parts by weight of liquid epoxy resin; (B) modified polyolefin resin powder having an average particle size of approximately 0.9 to 1.5 times the set adhesive layer thickness and a melting point of 70 to 190°C. (C) 1 to 50 parts by weight of a latent curing agent; and (D) 0.5 to 20 parts by weight of a latent amine adduct type curing agent. (3) An adhesive composition, wherein the adhesive composition according to claim (1) or (2) is an adhesive composition for a hemming part of an automobile body.