JPH05112697A - Ordinary temperature adhesive epoxy resin composition and formation of vibration-damping material from the composition - Google Patents

Abstract

PURPOSE:To provide a composition comprising a specific epoxy resin, a conjugated diene copolymer rubber, an inorganic filler and a curing agent, capable of being readily coated on a target member for vibration damping, and giving cured products having good vibration-damping functions. CONSTITUTION:The objective epoxy resin composition comprises (A) 100 pts.wt. of an epoxy resin comprising 1-30 pts.wt. of an epoxy resin liquid at the ordinary temperature and an epoxy resin solid at the ordinary temperature, (B) 10-100 pts.wt. of a carboxyl group-containing acrylonitrile conjugated dienic copolymer rubber, (C) 50-500 pts.wt. of a scaly inorganic filler and (D) a curing agent. A liquid epoxy resin having an epoxy equipment of 150-600 and a solid epoxy resin having an epoxy equivalent of 450-2500 are preferably employed as the component A. The component B has preferably a carboxy group content of 0.01-0.2EPHR and contains preferably butadiene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature adhesive epoxy resin composition suitable for a vibration damping material having a vibration damping function in a high temperature region, and a method for forming a vibration damping material using the same.

[0002]

2. Description of the Related Art A vibration damping material is attached to a vibration-generating machine or equipment or a metal plate as a cover thereof for the purpose of preventing or reducing vibration or for preventing resonance or resonance. It has already been proposed to use a cured product of an epoxy resin composition as such a damping material. For example, JP-A-62-64854 proposes a composition for a vibration damping material, which comprises a butadiene oligomer having a carboxyl group, an amino group or an imino group in the molecule, an epoxy resin, an inorganic filler and a curing agent,
Further, Japanese Patent Application Laid-Open No. 03-759 also proposes a viscoelastic resin for a vibration damping material, which is composed of an epoxy resin, a curing agent and a thermoplastic resin.

However, in the epoxy resin composition which has been concretely proposed in the past, an epoxy resin which is solid at room temperature is exclusively used as the epoxy resin. The reason is that an epoxy resin which is liquid at room temperature usually has a low molecular weight, and the use of such an epoxy resin does not give a sufficient vibration damping function to the cured product. On the other hand, it is impossible at room temperature to apply a composition using an epoxy resin that is solid at room temperature to a member to be damped, and it is heated to plasticize the composition and develop self-adhesiveness. There was a need. In that case, of course, appropriate equipment is required, and the work and process become complicated, and the hardening progresses by heating to increase the viscosity, so that the work had to be performed within a short working time.

On the other hand, in order to damp vibration of high temperature members such as oil pans, rocker arm covers, cylinder blocks, manholds, etc. of automobiles, it is about 80 to 120 ° C.
However, it is hard to say that the conventional vibration-damping epoxy resin composition has sufficiently functioned.

[0005]

Thus, the object of the present invention is to easily adhere to a member to be vibration-damped at room temperature, and at the high temperature of 80 to 120 ° C., the cured product has a sufficient vibration-damping function. It is an object of the invention to provide such an epoxy resin composition having and to provide a method of forming a damping material from such a composition.

[0006]

According to the present invention, _{1 to} 30 parts by weight of an epoxy resin (A ₁ ) which is liquid at room temperature and 99 to 70 parts by weight of an epoxy resin (A ₂ ) which is solid at room temperature (herein). 100 parts by weight of an epoxy resin (A) consisting of 100 parts by weight of A ₁ and A ₂ ) and a carboxyl group-containing acrylonitrile conjugated diene copolymer rubber (B) 10
Provided is a room temperature adhesive epoxy resin composition having 100% by weight, 50 to 500 parts by weight of a scale-like inorganic filler (C) and a curing agent (D) and having a vibration damping function, and further the composition. Provided is a method for forming a vibration damping material on a member to be vibration-damped by self-adhesion, and heating the composition to heat the composition.

The present invention will be specifically described below. Epoxy Resin (A) As the epoxy resin (A) used in the composition of the present invention, a liquid epoxy resin (A ₁ ) at room temperature and a solid epoxy resin (A ₂ ) at room temperature are used together in specific amounts. By using a small amount of the epoxy resin (A ₁ ) which is liquid at room temperature, the composition becomes plastic and self-adhesive at room temperature.

The epoxy resin (A ₁ ) is 1 to 30 parts by weight,
The epoxy resin (A ₂ ) is used in an amount of 99 to 70 parts by weight (the total amount of (A ₁ ) and (A ₂ ) is 100 parts by weight), but the amount of the epoxy resin (A ₁ ) is too small. When (the amount of epoxy resin (A ₂ ) is too large), the plasticity of the composition is lost and the self-adhesiveness is lost. On the other hand, on the contrary, if the amount of the epoxy resin (A ₁ ) is too large (the amount of the epoxy resin (A ₂ ) is too small), the vibration damping function at high temperature of the cured product is poor. In this sense, the preferable blending amount of the epoxy resin (A ₁ ) is 10 to 30 parts by weight, and the preferable blending amount of (A ₂ ) is 90 to 70 parts by weight.

The epoxy resin used may include epoxy resins derived from polyhydric phenols and epihalohydrins. Preferred epoxy resins include 2,2-bis (4-hydroxyphenyl) propane: (bisphenol A), 1,1-bis (4-hydroxyphenyl) ethane: (bisphenol AD), bis (4-hydroxyphenyl) methane. : An epoxy resin derived from a dihydric phenol exemplified by (bisphenol F) and epichlorohydrin. The epoxy resin (A ₁ ) which is liquid at room temperature has a low molecular weight among the above epoxy resins and has an epoxy equivalent of 15
It is about 0 to 600. In addition, the epoxy resin (A ₂ ) which is solid at room temperature is a high molecular weight epoxy resin having an epoxy equivalent of 450 or more, particularly 450 to 2500, among the above-exemplified epoxy resins.

Carboxyl group-containing acrylonitrile co
Role of diene copolymer rubber (B) The copolymer rubber (B) is compounded in the composition of the present invention in an amount of 10 to 100 parts by weight, preferably 15 to 90 parts by weight, based on 100 parts by weight of the epoxy resin. This copolymer rubber contains a carboxyl group, but this functional group reacts with the epoxy group of the epoxy resin during heat curing to bond with the epoxy resin chain, and as a result, crosslinks to a rigid polymer chain. It has a structure in which it is combined with a flexible rubber chain, and exhibits a vibration damping effect at high temperatures in combination with the compounding of a filler described later.

The carboxy content of the copolymer rubber (B) is 0.
001-0.3EPHR (COOH per 100g of rubber
(Equivalent weight), particularly 0.01 to 0.2 EPHR is preferable.
If the carboxy content is too high, the properties as a rubber will be lost, and if the carboxy content is too low, the epoxy resin and the copolymer rubber will be less bound, and in either case, the vibration damping effect at high temperatures will not be fully exerted.

Examples of the conjugated diene which is a constituent component of the copolymer rubber (B) include butadiene and isoprene, with butadiene being preferred. The content of acrylonitrile in the copolymer rubber (B) is 18 to 50% by weight, preferably 26 to 50% by weight.
It is 34% by weight. The copolymer rubber (B) has a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 25 to 80, especially 30.
The thing of -70 is preferable.

Such a carboquine-containing acrylonitrile / conjugated diene copolymer rubber (B) can be produced by a known method, and is commercially available, for example, from Ube Industries under the trade names CTBN and Nippon Zeon under the trade names Nipol 1072,
It is easily available.

The copolymer rubber (B) is added in an amount of 10 to 100 parts by weight, preferably 10 to 90 parts by weight, based on 100 parts by weight of the epoxy resin (A). If the blending amount of the copolymer rubber is too large or too small, a sufficient vibration damping effect cannot be obtained.

Incorporation of the scale-like inorganic filler (C) and the filler (C) provides the cured damping material with sufficient strength, and also the epoxy resin (A) and the copolymer rubber (B).
Synergistically works with high temperature to provide excellent damping effect.

The amount of the filler (C) blended is 50 to 500 parts by weight, preferably 75 to 300 parts by weight, based on 100 parts by weight of the epoxy resin (A). If the content is too large, the cured product will be brittle and will not function as a vibration damping material. If it is too small, the strength of the cured product will be reduced and the vibration damping property will be reduced.

The filler (C) is in the form of flakes, and examples thereof include mica, graphite, boron nitride, molybdenum disulfide, talc and the like, with mica being particularly preferred. A 20-mesh (Tyler) pass, particularly a 40-mesh pass is preferable.

Hardener The hardener is a hardener generally used for epoxy resins, and includes amines, polyamines, polyamine polyamides, acid anhydrides, basic active hydrogen compounds, tertiary amines, imidazoles. In the present invention, since the curing temperature is 140 to 160 ° C., a curing agent suitable for it may be appropriately selected. Particularly preferable curing agents include dicyandiamide, which is a latent curing agent, and polyadipic anhydride, which is an aliphatic acid anhydride.

The amount of the curing agent used is appropriately selected according to the type of the curing agent. For example, dicyandiamide is used in an amount of 5 to 15 parts by weight based on 100 parts by weight of the epoxy resin.

Preparation of Composition The composition of the present invention can be prepared by adding the components (A) to (D) in any order. At this time, the kneader,
A mixer such as a Banbury mixer can be used, but when a roll such as an open roll is used, after the mastication of the copolymer rubber (B) is performed, the epoxy resin (A) is added, and (A) is added. And (B) are uniformly dispersed. After this,
Add filler (C). Further, an appropriately selected curing agent (D) is added. Finally, the composition can be prepared as a sheet of several mm.

[0021] Since the deposition thus prepared composition to a subject member has a self-adhesive, members to be damping, cold example automotive oil pan, rocker arm cover, cylinder Glock, manifold to such Can be applied with. Although it can be done manually by humans,
It can be performed using a device such as a roll or a press. Since the pot life can be made sufficiently long, it is possible to perform the work of carefully attaching even a complicated shape. When applied, the thickness of the composition is selected from the most preferable value from the material of the adherend and the thickness of the adherend so as to exert its vibration damping effect. For example, in the case of a steel plate, it is preferably about 1 to 1.25 times the thickness of the steel plate.

Formation of Damping Material After the composition is applied to the member to be damped, the composition is cured to form the damping material in close contact with the member. Usually, this curing is carried out by heating, and at that time, it is carried out by using an apparatus such as an oven or a hot-air oven, and the heating temperature is usually 140, although it depends on the kind of the curing agent.
The composition is heated to ~ 160 ° C.

The member formed with the vibration damping material as described above exhibits excellent vibration damping properties.

[0024]

EXAMPLES The present invention will be described in more detail below with reference to examples.

(Examples 1 to 7 and Comparative Examples 1 to 24) Sheet-shaped compositions comprising epoxy resin, rubber filler and dicyandiamide in the proportions shown in Table 1 were prepared using an open roll. (Although the amount of dicyandiamide is not shown in Table 1, it is 20% with respect to 100 parts by weight of the epoxy resin.
Parts by weight were used. Further, the ratio of each component in Table 1 is shown in parts by weight. )

However, each component in Table 1 has the following composition and physical properties.

Measurement of vibration damping performance A steel plate having a width of 11 mm, a length of 250 mm and a thickness of 1.6 m was coated with the uncured sheet having a thickness of 2 mm prepared above, and 1
It was cured at 50 ° C. for 30 minutes, and a measurement sample in which the vibration damping material was adhered to the steel plate was prepared. Material technology v
The loss coefficient η at 80 ° C., 100 ° C. and 120 ° C. was measured by the one-end fixed forced vibration resonance method described in ol 2, No. 6, page 328.

That is, one end of the test piece is fixed at 50 mm, vibration is applied from the free end by an electromagnetic exciter, the displacement of the test piece is picked up, a frequency-dB curve is drawn by a high speed level coder, and resonance is performed. Point f ₀ and point f 3 dB lower than f _{0
The full} width at half maximum was measured from ₁ and f ₂ and the loss coefficient was calculated by the following formula. η = Δf / f ₀ (Δf = f ₂ −f ₁ ) A large η means that vibration damping performance is excellent.

Measurement of adhesiveness (self-adhesiveness) The self-adhesive sheet is adhered to a steel plate with a roll. This steel sheet was inserted into an oven set to 140 ° C. to 160 ° C., which is the curing condition, and fixed with the sheet surface facing downward and in the vertical direction. Adhesion between the sheet and the steel sheet during and after the curing treatment. Was evaluated. That is, when the sheet was not visually observed to be slipped down,
○, when a slight deviation was observed, it was evaluated as ×.
The above results are shown in Table 1.

From this table, it is understood that the composition of the present invention has excellent self-adhesiveness and that the cured product thereof has an excellent function as a vibration damping material at a temperature of 80 to 120 ° C.

[0031]

[Table 1]

[Table 2]

[Table 3]

[0032]

Since the composition of the present invention is plastic at room temperature and has self-adhesiveness, it can be applied to a member to be vibration-damped at room temperature. A damping material having an excellent damping function at high temperature is obtained, and the damping material is firmly adhered to the member.

Claims (2)

[Claims] 1. An epoxy resin (A ₁ ) 1-3 which is liquid at room temperature.
0 parts by weight, and epoxy resin (A ₂ ) 9 which is solid at room temperature
100 parts by weight of epoxy resin (A) consisting of 9 to 70 parts by weight (here, the total amount of A ₁ and A ₂ is 100 parts by weight), 10 to 100 parts by weight of carboxyl group-containing acrylonitrile conjugated diene copolymer rubber (B) Part, 50 to 500 parts by weight of scale-like inorganic filler (C) and a curing agent (D), which is a room temperature adhesive epoxy resin composition having a vibration damping function. 2. A method for forming a vibration damping material on a member to be vibration-damped by applying the composition according to claim 1 to the member to be damped by self-adhesive force, and heating and curing the deposited composition. ..