JPS612780A - Adhesive composition - Google Patents

Abstract

PURPOSE:The titled composition that contains an epoxy resin composition which consists of a polyfluorated epoxy resin represented by a specific formula and allyl glycidyl ether, and a curing agent, thus giving uncuring composition and cured products good properties. CONSTITUTION:The objective composition is obtained by using an epoxy resin composition which is composed of (A) a polyfluorated epoxy resin represented by the formula (n is 0 or optional positive integer) and (B) an allyl glycidyl ether, preferably in an amount of 5-25wt% based on the epoxy resin composition, and a curing agent and, when needed, a curing accelerator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an epoxy resin adhesive composition, which is a novel adhesive composition containing a specific epoxy resin. More specifically, the present invention relates to an epoxy resin adhesive composition that has improved physical properties both when uncured and when cured.

[Conventional technology]

Epoxy-based adhesive compositions are generally known as adhesive compositions. Such an adhesive composition has adhesive strength, flexibility, heat resistance, wettability to adherends, optical transmission loss,
The refractive index is thicker (different. Also, the viscosity when uncured, the defoaming property after mixing, the pot life, the curing temperature and the curing time are also different. Traditionally, K and K are used to improve adhesive strength and heat resistance. Adhesive compositions have been developed that use additives such as Suphenol A-based epoxy resins, fillers, and compulsions, and that use polyglycol-type epoxy resins to improve flexibility and properties.Also, Adhesive compositions are mixed with low-viscosity diluents to reduce uncured viscosity and improve defoaming properties after mixing, and acid anhydride curing agents are used to extend pot life. Adhesive compositions used: Adhesive compositions using amine-based curing agents have been developed to lower the curing temperature and shorten the curing time.However, when using bisphenol A-based epoxy resin, Poly has the disadvantage of high viscosity when uncured. Addition of fillers and campling agents can lead to poor viscosity, and it is difficult to keep optical transmission loss low. The use of glycol-type epoxy resin has the disadvantage of poor heat resistance, adhesive strength, etc., and the addition of a low-viscosity diluent may also impair heat resistance.In particular, heat resistance and adhesive strength may deteriorate. It has been extremely difficult to obtain adhesive compositions that are excellent in both properties.Additionally, these adhesives that have been developed so far have a large refractive index and are suitable for use with quartz fibers, which are often used in optical communication line traps. Since refractive index matching cannot be achieved with optical members having a small refractive index such as BK7 glass, KzF2 glass, etc., if the optical members are not bonded together, the reflection of the optical signal at the end face will increase and the signal strength will decrease. There were drawbacks such as deterioration and unstable operation of the light emitting element.

[Problem to be solved by the invention 3 An adhesive composition containing a multifluorinated epoxy resin has been developed as an adhesive composition that solves the above drawbacks and has excellent wettability to adherends. , multifluorinated epoxy resins are solid or pasty liquids at room temperature, so it is difficult to mix them at room temperature, and it is necessary to heat them to around 70°C to mix them uniformly, and their pot life is short. There was a drawback.

Furthermore, when introducing an adhesive composition into the optical path, if bubbles remain in the cured product, scattering and reflection of transmitted light will increase, increasing transmission loss. It is necessary to completely defoamer. However, in many conventional adhesive compositions, it is difficult to defoam within the bond life after mixing with a curing agent, and it is necessary to introduce the composition into the optical path while leaving small bubbles, or to remove the bubbles in a vacuum. However, there was a disadvantage in that it required a device that could mix the two without generating any.

The object of the present invention is to provide adhesive compositions which do not have these disadvantages.

[Means to correct the problem]

In summary, the present invention is an invention of an adhesive composition, which is an adhesive composition having a composition represented by the following general formula I: [wherein n represents 0 or any positive number]. It is characterized by containing an epoxy resin composition consisting of a fluorinated epoxy resin and allyl glycidyl ether, and a curing agent.

Examples of the curing agent used in the present invention include amine compounds such as triethylenetetramine, polyamide resin compounds, and acid anhydride compounds such as methylnadic anhydride. The blending amount of such a curing agent provides a cured product with excellent adhesive strength, flexibility, heat resistance, and wettability to adherends, as well as low optical loss, low refractive index, and excellent mating properties with optical components. From this point of view, it is desirable that the amount of the curing agent be 08 to 18 per equivalent of epoxy group contained in the epoxy resin.

In addition, in the present invention, a curing accelerator such as benzyldimethylamine and 2-ethyl-4-methylimidazole may be blended as necessary. The amount of the curing accelerator to be blended is preferably 5 to 2 parts by weight of C.alpha. per 100 parts by weight of the epoxy resin. In addition, various modifiers, extenders, softeners, etc. can also be appropriately blended.

Figure 1 shows that among the polyfluorinated epoxy resins (hereinafter abbreviated as FEp) represented by the structural formula I, an epoxy resin with an epoxy equivalent of 290 and n in the formula of α3 is combined with allyl glycidyl ether (hereinafter AC) E This shows the viscosity at 25°C of the epoxy resin composition when mixed with That is, the first
The figure shows the blending ratio (wt%) of AGE (horizontal axis) and viscosity η25
(cps) (vertical axis).

In the case of only FKp, it is paste-like (viscosity cannot be measured, 200.000 cps or more) at 25°C, so it is difficult to mix uniformly with the curing agent, and a heating operation is required for uniform mixing.

In this case, since the reaction with the curing agent is accelerated by heating, the pot life after mixing is shortened and workability is significantly inferior.

On the other hand, an epoxy resin composition containing AGE has a viscosity of 20,000 centipoise (cps) or less, and can be mixed with a curing agent at room temperature. It has features such as being able to be filled. Furthermore, it has the following five characteristics: the viscosity can be adjusted by changing the amount of AGE blended as necessary, and it is clear that the workability has been improved and the range of application has been expanded.

Here, when used as an adhesive, the viscosity is 50,000
As mentioned above, when the viscosity is higher than about 0 cps, it is difficult to mix uniformly with the curing agent, and the reverse K is 200 cps.
If the viscosity is lower than that, it will be difficult to apply thickly to the adherend, and there will be a possibility that it will flow out from the fixed part while being left under curing conditions.

From the above, the blending ratio of AGE is such that the viscosity of the epoxy resin composition is 200. It is desirable that the amount is 5 to 25% by weight in the composition so that the OD Ocps is in the range of cps to 5 i) and OD Ocps.

Table 1 below shows the viscosity and surface tension of epoxy resin compositions containing FEp Ic AGE.
Table Comparative Example 1 is a case of FEp only, and Comparative Example 2 is a case of Epicote 828 (Yuka Shell Epoxy Co., Ltd. jR), which is the most common liquid resin among commercially available bisphenol A type epoxy resins.
It is.

All three types of examples of the present invention have a low viscosity, and it is clear that by blending AGE, it is possible to mix uniformly with the curing agent at room temperature under pressure.

The wettability of the adhesive composition to the adherend depends on the surface tension of the composition, and the lower the surface tension, the easier it is to wet the adherend. The three compositions of the invention examples have a surface tension of 9 dyn compared to the control example 2.
/cm or more, and it is clear that it has excellent wettability to adherends.

Furthermore, since the viscosity of the examples of the present invention is low, it is clear that filling into fine structure parts is also possible. but not limited to.

Example 1 NIL2aycFwp and AGE? : Adhesive composition using two types of polyamide compounds (trade name: Persamide V-140, Persamide V-150, both manufactured by Henkel Nippon Co., Ltd.) as a mixed epoxy resin composition trap curing agent.
Optical loss at a wavelength of 13 μm when heated at c for 15 hours and cured at °C, refractive index (nD23) when sodium D line (wavelength 589.3 nm) is used as a light source, bot life, and vacuum when mixed at room temperature Indicates the time required for defoaming.

Comparative Example 11F This is a case in which only F and P are epoxy resins and the curing agent KV-140 is used, and Comparative Example 2 is a case in which Epikote 828 and V-140 are used as a comparison? ! I3 is a conventionally used commercially available optical adhesive (Rensbond M62,
(manufactured by Somers).

It can be seen that the light transmission loss of the example is equivalent to that of the comparative example, and the transmission loss is small even when used in the optical path.

The refractive index of the example is much smaller than that of comparative example 2.6, and is similar to that of quartz fiber (nD”=t46) or BK7 glass (n-=t
5164) and KzF 2 glass (np”=1.529
It is clear that the matching properties are excellent when optical members such as 4) are bonded together.

In addition, the pot life of the example at 25°C is 3 hours or more, which is longer than that of Comparative Example 1.3, and defoaming can be easily performed in 3 to 5 minutes at 25°C and 3 mHg conditions.
It is clear that workability is improved and scattering and reflection of transmitted light due to bubbles can be reduced.

Example 2 A polyamide-based compound (trade name: Persamide V-14) was added as a curing agent to an epoxy resin composition in which FEp and AGE were mixed.
0, manufactured by Henkel Japan Co., Ltd.) ft epoxy resin composition 100
Optical loss at a wavelength of 16 μm and refractive index (nD
FIG. 2 shows the results of an investigation on the dependence of AGE addition amount of zx). That is, FIG. 2 is a graph showing the relationship between the blending ratio (% by weight) of AGE (horizontal axis) and the refractive index nD23 or light transmission loss (%) (vertical axis) of the cured product. All measurements were performed at 23°C. The sample thickness at the time of optical loss measurement was 1 mm.

It can be seen that the optical loss is very small, about 1%, regardless of the amount of AGE. nD! From the examination results of j, FEp and ACE
It was found that the refractive index (nt,) of a composition containing AGE becomes smaller as the amount of AGE mixed increases.

From the above results, it is clear that it is possible to adjust the refractive index (nD23) by adjusting the amount of AGE added.
It is clear that the mating property is excellent when two optical members such as glass are bonded together.

Example 6 A composition in which AGE was mixed with FEp K in a ratio of 15% by weight with respect to 85% by weight of FEp was used as an epoxy resin composition, and two types of polyamide compounds Persamide V-140 and Persamide V were used as curing agents. -150 (manufactured by Henkel Japan Co., Ltd.) Shear adhesive strength to copper when cured at 60°C for 15 hours, shear adhesive strength to quartz, and factors that define the heat resistance of the adhesive composition Table 3 shows the results of studies regarding the glass transition temperature (Tg), which is , and Young's modulus, which is a factor that determines flexibility. Comparative Example 4 is a commercially available flexible liquid adhesive (trade name: Pernosox MG-155, manufactured by Nihon Vernonx Co., Ltd.), and the epoxy resin includes a mixture of bisphenol A epoxy resin, polyglycol epoxy resin, and a curing agent. uses a mixture of a modified heterocyclic polyamine and a modified aliphatic polyamine.

In conventional adhesive compositions, 5KTg as shown in Comparative Examples 1 to 4
A cured product with a high Young's modulus also has a large Young's modulus (it was difficult to obtain a cured product with excellent both heat resistance and flexibility. However, in Example 6, a Young's modulus of t5 It is clear that the cured product having the same has a high Tg of 62°C, and a cured product having excellent both flexibility and heat resistance can be obtained.

In the examination of the shear adhesive strength of Examples and Comparative Examples, for quartz used as an example of an optical member, a large shear adhesive strength that would lead to breakage of the adherend was obtained in all cases.

From the results of examining the shear adhesive strength to copper, it was found that the adhesive strength of Example 3 was higher than that of Comparative Example 1 except for Comparative Example 2, which had a large Young's modulus.
．． It can be seen that it is larger than 6.4. In addition, Example 6
The Young's modulus of Example 6 is smaller than that of Comparative Example 1.2.5, and the decrease in Tg due to the reduction of the Young's modulus is small in Example 6.

From the above results, it is clear that the examples provide cured products that are superior in the three properties of adhesive strength, heat resistance, and ductility compared to the comparative examples.

Example 4 FIG. 3 shows the results of examining the shear adhesive strength to steel when the amount of AGE added was varied in an epoxy resin composition containing a mixture of FEp and AGR.

In other words, Figure 6 shows the blending ratio (wt%) of AGR (horizontal axis).
It is a graph showing the relationship between and the shear adhesive strength (ky f /cm2) (vertical axis) of the cured product. The curing agent was added in an amount of 50 parts by weight per 100 parts by weight of the Persamide V-140)i epoxy resin composition, and the curing conditions were 60° C. for 15 hours. Moreover, the measurement was performed under conditions of 23° C. and 65% relative humidity.

From FIG. 5, it can be seen that the adhesive strength reaches its maximum value when 15% by weight of AC)E is added, and when more than 15% by weight is added, the adhesive strength begins to decrease. In particular, the decrease is remarkable when 35% by weight or more is added.

When AGE was added in an amount of 5 to 25% by weight, the adhesive strength varied in the range of 90 to 110 kyf/cm'', but no rapid decrease occurred, and in all regions it was 60 to 9 f.
It can be seen that an adhesive strength of /lyn'' or more can be obtained.In addition, in Fig. 6, the composition of only FEp and curing agent without AGEz-mixing needs to be mixed after heating to 70°C.
It is difficult to use below ℃.

From the above results, it is clear that the composition containing 5 to 25% by weight of AGE is an adhesive composition that can be mixed at room temperature and has excellent adhesive strength.

In this example, n = 0.5, but similar results were obtained when n = 0 to 7.

〔Effect of the invention〕

As detailed above, the present invention has excellent adhesive strength, flexibility, heat resistance, and wettability to adherends, as well as low optical loss and
It provides a cured product with a low refractive index and excellent mating properties with optical fibers, optical lenses, etc. It also has low viscosity at room temperature when uncured, has excellent defoaming properties, has a long pot life, and can be cured even at low temperatures. This has the remarkable effect of being able to provide a highly adhesive composition.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the blending ratio of the mixed epoxy resin composition and viscosity; Figure 2 is a graph showing the relationship between the blending ratio of the mixed epoxy resin composition and the refractive index or light transmission loss of the cured product; FIG. 3 is a graph showing the relationship between the blending ratio of the mixed epoxy resin composition and the shear adhesive strength of the cured product.

Claims (1)

[Claims] 1. The following general formula I: ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) [However, n in the formula represents 0 or any positive number] An adhesive composition comprising an epoxy resin composition comprising a polyfluorinated epoxy resin and allyl glycidyl ether, and a curing agent. 2. The adhesive composition according to claim 1, wherein the allyl glycidyl ether is blended in a proportion of 5 to 25% by weight in the epoxy resin composition.