JPH0342317B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention has excellent vibration damping characteristics in a wide temperature range from low to high temperatures, has good workability when applied to damped panels, and is compatible with damped panels. This relates to panel vibration damping materials with excellent adhesion. (Conventional technology) Conventionally, vibration damping materials have been used for vehicle bodies such as automobiles and railway vehicles, engines,
In panel structures such as prime movers such as motors, housings of electrical equipment, and fluid transport ducts,
Damping material is attached to the panel surface to reduce vibration. Such panel damping materials are required to have a large loss coefficient (η) evaluated in a composite system with the damped panel [Noise Countermeasures Handbook, edited by Japan Acoustic Materials Association, p. 21], and It is desired to have a large loss coefficient (η) over a wide temperature range if possible. The reason for this is that the object to be damped is not necessarily used in an air-conditioned environment; for example, when considering use in an automobile panel, depending on the season,
In addition to the external environment due to solar radiation and region, the temperature of the damped panel changes depending on the internal environment such as the engine, exhaust, and air conditioning. Such temperature changes are generally considered to range from -40°C to 120°C, and a damping material having a large loss coefficient at least in a temperature range of about 0°C to 80°C is ideal. Furthermore, as the thickness of the damped panel becomes thicker and the thickness of the damping material becomes thinner, the damping effect deteriorates. Therefore, for automobiles, the maximum thickness of the vibration damping panel used is about 0.8 mm, and it is desired that sufficient vibration damping performance can be obtained even with this thickness. Also, the thickness of the damping material is required to be 3.5 mm or less, taking into consideration the weight of the vehicle. Furthermore, it is desired that the panel damping material can be easily adhered to the damped panel. For example, when the damped panel is an automobile floor panel, it has a complex surface shape by adding beads, embossing, and curved surfaces. It is a problem in terms of work that it takes a lot of effort to uniformly adhere the damping material to the surface of the damped panel. For example, as vibration damping materials for automobile floor panels, heat-melting point type materials have been known that are made mainly of asphalt, a thermoplastic material, with fillers and modifiers added (Unexamined Japanese Patent Publication No. Showa 57-
119553). In the automobile manufacturing process, thermosetting paint is used to paint the car body, so the car body is heated for about 30 minutes at a temperature of 140°C to harden the paint film. Asphalt-based damping materials utilize this heat to
The damping material sheet is placed in close contact with the vehicle body panel, and the worker simply places the damping material sheet on the damping panel, and the sheet melts due to heat, forming the complex shape of the damping panel using only its own weight. Follow and fuse. In this way, asphalt-based damping materials have self-adhesive properties that do not require the use of adhesives, and can be easily adhered to complex damped panels, making them excellent in terms of workability. (Problems to be Solved by the Invention) However, in conventional heat-sealing type vibration damping materials mainly composed of thermoplastic materials, the material must have sufficient fluidity at temperatures below 140°C. Therefore, the elastic modulus of the vibration damping material decreases significantly at temperatures above 40° C., and therefore, there is a drawback that sufficient vibration damping characteristics cannot be obtained at high temperatures. It is a well-known fact that in the case of exclusive damping materials, good damping characteristics cannot be obtained unless the damping material not only has a large loss coefficient (tanδ) but also a large elastic modulus. [Noise Countermeasures Handbook, edited by Japan Acoustic Materials Association, p. 443]. Therefore, the inventors aimed to achieve both excellent vibration damping properties from low to high temperatures and workability equivalent to that of conventional vibration damping materials whose main component is asphalt.
After various studies, we first focused on the adhesive properties of epoxy resin and conducted research. However, the epoxy resin alone, the curing agent, or the glass transition temperature (Tg)
It is not possible to obtain good vibration damping characteristics over a wide temperature range with a mixture of multiple epoxy resins and curing agents with different epoxy resins, or with a plasticizer, or with an inorganic filler added to the mixture. Ta. (Means for Solving the Problems) As a result of further research, the inventors discovered an epoxy resin, a liquid resin that is compatible with the epoxy resin and has a methylol group as an end group, and a curing agent. By incorporating inorganic fillers and inorganic fillers, we have created a panel vibration damping material that not only has excellent vibration damping properties in a wide temperature range from low to high temperatures, but also has excellent workability and adhesion to the damped panel. The epoxy resin used in the present invention has an average of one or more reactive epoxy groups per molecule, and includes bisphenol type, ether ester type, and novolac type. It includes various types such as epoxy type, ester type, and cycloaliphatic type, and these epoxy resins are used alone or in combination of two or more types.These epoxy resins are solid at room temperature. The liquid resin must be compatible with the epoxy resin and must contain a terminal group that is a methylol group.The compatibility with the epoxy resin is determined by the separation of the resin. This is necessary not only to prevent a decrease in the epoxy resin, but also to plasticize the epoxy resin.Also, the methylol group at the terminal group is necessary to facilitate the reaction with the epoxy resin, but all molecules have methylol groups. Liquid resins with these characteristics can be manufactured in various types through organic synthesis, but xylene resins, phenolic resins, etc. are examples of those that are industrially mass-produced. These resins are compatible with epoxy resins, and in the industrial manufacturing process, molecules containing molecules with methylol groups at the end groups are simultaneously produced, so complex processes such as special reaction processes and modification are required. It has the advantage of being easily obtained without requiring any process.Also, the resin has a low hygroscopicity and low volatile content, which can cause unintentional foaming when the panel damping material is cured, and the uncured resin has a long lifespan. Considering storage stability, etc., xylene resin is suitable.For example, xylene resin is an unmodified xylene-formaldehyde resin obtained from the reaction of meta-xylene and formaldehyde, and meta-xylene is mixed with methylene, dimethylene ether, and acetal. It is an oligomer with a number average molecular weight of 300 to 600 connected by chemical bonds such as.Furthermore, as mentioned above, in the production stage, oligomers containing molecules having a methylol group at the end group are simultaneously produced. These liquid resins can be used alone or in combination of two or more. As the curing agent used for curing the epoxy resin and liquid resin, any known curing agent for epoxy resins can be used, and one that matches the thermal history conditions of the panel vibration damping material may be selected. For example, acid anhydrides, imidazoles, imidazolines, etc. may be used, but considering the long-term storage of the panel vibration damping material, materials that are stable at room temperature and exhibit activity at high temperatures are preferred; However, nitrogen-containing compounds that decompose at elevated temperatures to yield at least one active hydrogen-containing amine are preferred. Typical examples include monourea, polyurea, hydrazide, and thiourea.
-(p-chlorophenyl)-1,1-dimethylurea, dicyandiamide, 2,4-bis(N,N-
dimethylcarbamide) toluene, etc., and these may be used alone or in combination of two or more. Next, there are no particular restrictions on the inorganic filler, such as mica, graphite, asbestos, talc, glass flakes, glass fiber, clay, calcium carbonate, sand, silica, etc., and combinations of these may also be used. . Next, regarding the blending amount of each component, it is necessary that the epoxy resin is contained in 5 to 75 parts by weight out of 100 parts by weight of the total amount of the epoxy resin and liquid resin. Further, the amount of the curing agent to be blended varies depending on the blending ratio of the epoxy resin to the liquid resin and the type of the curing agent, but the amount that can be easily calculated from the chemical equivalent may be used as a guideline for blending. Here, if the epoxy resin is less than 5 parts by weight out of 100 parts by weight of the total amount of epoxy resin and liquid resin, the peak of the composite system loss coefficient (η) that occurs on the high temperature side will be too low. The vibration damping characteristics are unsatisfactory and inappropriate, and if the epoxy resin exceeds 75 parts by weight, the peak of the composite loss coefficient (η) that occurs on the low temperature side becomes too low, so the vibration damping characteristics in the low temperature region are It is still inappropriate because it makes people think that Further, the amount of the inorganic filler to be blended is 30 parts by weight or more based on 100 parts by weight of the total amount of the epoxy resin and liquid resin. The effect of blending an inorganic filler is to increase the elastic modulus of the panel damping material, and if it is less than 30 parts by weight, it is inappropriate because almost no filling effect can be obtained. In addition, the maximum amount of inorganic filler can be easily calculated from the oil absorption amount specified by the type of filler, up to the maximum amount that can be physically mixed, but if it exceeds 350 parts by weight, the vibration damping panel The upper limit is preferably 350 parts by weight since the adhesion with The panel vibration damping material of this invention can cure the paint film by simply placing an uncured sheet formed to the desired thickness using an extruder or calendar roll on the panel to be damped. For this purpose, the sheet melts using the heat applied to the panel structure, and due to its own weight, it follows the shape of the damped panel even if it has a complex surface shape, and then the adhesive hardens.
It is a panel vibration damping material with excellent installation workability and adhesion to the damped panel. If a liquid low-viscosity epoxy resin is used and the amount of inorganic filler is small, the sheet will become paste-like, and if the uncured sheet is difficult to handle, the sheet should be heated slightly. In addition, so-called B-staging may be performed, or the material may be directly extruded onto the damped panel using an extruder or the like. (Function) In the panel damping material of the present invention, the cured product of the mixture of epoxy resin and liquid resin has a loss coefficient (η) evaluated in a composite system of the damped panel and the panel damping material.
Since it produces two or more peaks, it exhibits excellent vibration damping properties over a wide temperature range from low to high temperatures. Conventionally, as for the physical properties after curing of epoxy resin alone, there is one peak of the loss coefficient (η) of the composite system in the temperature range of around 100℃ to 170℃, but it is It is unsuitable as a material for vibration damping materials. On the other hand, in the damping material of the present invention, the cured product made by blending liquid resin with epoxy resin is a resin that is compatible with the epoxy resin, so it acts as a plasticizer for the cured epoxy resin product. It has the effect of lowering the peak of the composite loss coefficient (η) of the cured epoxy resin to below 80°C, which is the practical temperature range. Furthermore, the liquid resin reacts with the epoxy resin and has the effect of producing another peak of the composite loss coefficient (η) in the practical temperature range of 0° C. or higher. In other words, the peak of the composite loss coefficient (η) due to the plasticized epoxy resin is on the high temperature side below 80℃, and the peak of the composite system loss coefficient (η) due to the reaction between the epoxy resin and the liquid resin is on the low temperature side above 0℃. Therefore, excellent vibration damping properties can be exhibited over a wide temperature range from 0°C to 80°C. (Example) This invention will be explained by the following example and comparative example. The method for evaluating the damping properties of the panel damping material in the example, the shape followability for a damped panel having a complicated surface shape, and the adhesion to the damped panel are as follows. Evaluation method 1 [Vibration damping characteristics] On one side of a general automobile exterior steel plate with a length of 250 mm, a width of 15 mm, and a thickness of 0.8 mm, a plate of the same length and width and a thickness of 3.5 mm is placed on one side.
mm of uncured panel damping material, then heated to 140°C.
Heating was performed for 30 minutes to obtain a sufficiently adhered and hardened test piece for evaluating vibration damping characteristics. Using this test piece, the temperature dependence of the composite system loss coefficient (η) at the secondary resonance point of bending vibration is measured using the cantilever resonance method. Generally, it is said that it is preferable for the composite system loss coefficient (η) to be 0.05 or more in terms of damping characteristics. Evaluation method 2 [Shape followability] As shown in Figure 1, a=50mm, b=10mm, c=
Panel 1 with bead shape of 100mm, d=5mm
As shown in Figure 2, a panel damping material 2 with a length of 290 mm, a width of 100 mm, and a thickness of 3.5 mm was placed on top of the panel 1 and heated at 140°C for 30 minutes. Follow the bead shape and visually confirm that there are no gaps with the panel. Evaluation method 3 [Adhesion] As shown in Figure 3, the length is 20 mm, the width is 20 mm, and the thickness is
Prototype 3 yen of 3.5mm panel damping material test piece,
As shown in the figure, between two steel plates (panels) 4 with a length of 120 mm, a width (f) of 20 mm, and a thickness of 0.8 mm, d=20
mm, e = 100 mm, heated at 140°C for 30 minutes, cooled to room temperature, pulled in the direction of the arrow at a pulling speed of 100 mm/min, and the interface between panel damping material test peak 3 and panel 4 Measure the shear strength of 10Kgf/cm ² or more was considered excellent, 5Kgf/cm ² or less was considered poor, and 5 to 10Kgf/cm ² was considered good. Example 1 Epoxy resin (manufactured by Yuka Ciel Epoxy Co., Ltd., trade name "Epicote 1004") 5 parts by weight, xylene resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Nicanol H") 95 parts by weight
Parts by weight were mixed for 1 hour in a Burberry mixer heated to 150°C to ensure sufficient miscibility. This at 60℃
2 parts by weight of dicyandiamide, 3-(p-chlorophenyl)-1,1 as a curing agent
- 2 parts by weight of dimethyl urea and talc as an inorganic filler (manufactured by Kunimine Kogyo Co., Ltd., trade name "GTA")
150 parts by weight was added and kneaded at 60° C. for 1 hour. Next, it was formed into a sheet with a thickness of 3.5 mm using a calendar roll. The above evaluation method 1 for this sheet form
The results of the evaluation according to 3 are shown in curve 1 in FIG. 4 and in Table 1. In addition, the resin in the following examples and comparative examples,
The mixing method of the curing agent and the inorganic filler, and the sheeting method were the same as in Example 1 unless otherwise specified. The types of curing agents were dicyandiamide and 3-3, the same as those used in Example 1, considering that a sufficient cured product could be obtained by heating at 140°C for 30 minutes.
A mixture of equal parts by weight of (p-chlorophenyl)-1,1-dimethylurea was used in the following Examples and Comparative Examples. For example, a description of 10 parts by weight of the curing agent indicates a mixture of 5 parts by weight of dicyandiamide and 5 parts by weight of 3-(p-chlorophenyl)-1,1-dimethylurea. Example 2 25 parts by weight of epoxy resin (manufactured by Yuka Ciel Epoxy Co., Ltd., trade name "Epicote 828"), xylene resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Nicanol HH")
75 parts by weight, 6 parts by weight of hardening agent, calcium carbonate as an inorganic filler (manufactured by Nitto Funka Kogyo Co., Ltd., product name: NS
A panel damping material consisting of 150 parts by weight (#200) was obtained.
The results of evaluation using evaluation methods 1 to 3 are shown in curve 2 in Figure 4.
and shown in Table 1. Example 3 45 parts by weight of epoxy resin (manufactured by Yuka Ciel Epoxy Co., Ltd., trade name "Epicote 1001"), xylene resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Nicanol LL")
55 parts by weight, 8 parts by weight of hardening agent, 100 parts by weight of clay as an inorganic filler (manufactured by Kunimine Industries Co., Ltd., trade name "Kunimine Clay"), mica (manufactured by Kuraray Co., Ltd., trade name "SUZORITE MICA 60S") A panel damping material consisting of 50 parts by weight was obtained. The results of evaluation by evaluation methods 1 to 3 are shown in Curve 3 in FIG. 4 and Table 1. Example 4 25 parts by weight of epoxy resin (“Epicote 1001”),
20 parts by weight of epoxy resin (manufactured by Yuka Ciel Epoxy Co., Ltd., trade name "Epicote 871"), 55 parts by weight of xylene resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Nicanol L"), 8 parts by weight of curing agent. A panel damping agent was obtained containing 100 parts by weight of talc (GTA) as an inorganic filler and 50 parts by weight of glass fiber (manufactured by Unitika U.M. Glass Co., Ltd., trade name "ES 25T"). The results of evaluation using evaluation methods 1 to 3 are shown in Curve 4 in FIG. 4 and Table 1. Example 5 50 parts by weight of epoxy resin (“Epicote 104”),
25 parts by weight of xylene resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Nicanol LLL"), 25 parts by weight of "Nicanol H", 8 parts by weight of curing agent, talc (manufactured by Kunimine Kogyo Co., Ltd., product name) as an inorganic filler. A panel damping material consisting of 150 parts by weight (named "GAT") was obtained. The evaluation results according to evaluation methods 1 to 3 are shown in Curve 5 in FIG. 5 and Table 1. Example 6 50 parts by weight of epoxy resin (“Epicote 828”),
50 parts by weight of phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., trade name "PR-51670") was mixed for 30 minutes in a Banbury mixer heated and depressurized to 20 mmHg at 40°C to remove low boiling point components in the phenolic resin. Thereafter, the pressure was returned to normal, and 8 parts by weight of a curing agent and 150 parts by weight of talc ("GTA") as an inorganic filler were added and mixed at 40°C for 1.5 hours. Next, it was formed into a sheet with a thickness of 3.5 mm using a calendar roll. The evaluation results according to evaluation methods 1 to 3 are shown in curve 6 in FIG. 5 and Table 1. Example 7 75 parts by weight of epoxy resin (“Epicote 1001”),
A panel damping material consisting of 25 parts by weight of xylene resin (Mikanol L), 10 parts by weight of a hardening agent, and 150 parts by weight of calcium carbonate (manufactured by Nitto Funka Kogyo Co., Ltd., trade name "NS#400") was used as an inorganic filler. The evaluation results according to evaluation methods 1 to 3 are shown in curve 7 in FIG.
10 parts by weight of xylene resin (Nicanol L), 10 parts by weight of curing agent, talc ("GTA") as an inorganic filler
A panel damping material consisting of 150 parts by weight was obtained. The evaluation results according to evaluation methods 1 to 3 are shown in curve 11 in FIG. 5 and Table 1. Example 8 40 parts by weight of epoxy resin (“Epicote 1001”),
60 parts by weight of xylene resin (Nicanol H), 8 parts by weight of hardening agent, talc ("GTA") as an inorganic filler
A panel damping material consisting of 30 parts by weight was obtained. Evaluation method 1
The evaluation results from curve 8 and curve 1 in Figure 6 are
Shown in the table. Example 9 Among the formulations shown in Example 8, only the inorganic filler talc ("GTA") was increased to 250 parts by weight to obtain a panel damping material. The evaluation results from evaluation methods 1 to 3 are shown in the 6th
It is shown in curve 9 in the figure and in Table 1. Example 10 Among the formulations shown in Example 8, only the inorganic filler talc ("GTA") was increased to 350 parts by weight to obtain a panel damping material. The evaluation results from evaluation methods 1 to 3 are shown in the 6th
It is shown in curve 10 in the figure and in Table 1. Comparative Example 2 A panel damping material was obtained from the formulation shown in Example 8, which did not contain an inorganic filler and was composed of an epoxy resin, a xylene resin, and a hardening agent. The evaluation results according to evaluation methods 1 to 3 are shown in curve 12 in FIG. 6 and Table 1. Comparative Example 3 Asphalt-based heat-adhesive sheet (manufactured by Japan Tokushu Toyo Co., Ltd., trade name: Melsheet), which is currently widely used as a damping material for automobile floor panels (thickness: 3.5 mm) cm ² , Tests were conducted according to evaluation methods 1 to 3. The results obtained are shown in curve 13 in FIG. 6 and in Table 1.

【table】

[Table] (Effects of the Invention) The panel vibration damping material of the present invention is composed of an appropriate amount of a mixed resin of an epoxy resin and a liquid resin including one having a methylol group, and a curing agent and an inorganic filler. It exhibits good damping characteristics with a loss coefficient of 0.06 or more over a wide temperature range, that is, a highly practical temperature range of 0°C to 80°C, and also has excellent shape followability and adhesion, making it easy to attach to the panel to be damped. It also has the advantage of being easy.

[Brief explanation of drawings]

Figure 1 is a perspective view of the bead-shaped panel used in evaluation method 2, Figure 2 is a perspective view of the panel damping material temporarily placed on the bead-shaped panel in Figure 1, and Figure 3 is the test used in evaluation method 3. A perspective view of the piece, Figure 4 is evaluation method 1
Figure 5 is a curve diagram showing the damping characteristics of Examples 1 to 4 according to the evaluation method 1.
and a curve diagram showing the damping characteristics of Comparative Example 1, Figure 6 shows Examples 8 to 10 according to Evaluation Method 1, and Comparative Example 2.
and a curve diagram showing vibration damping characteristics of Comparative Example 3. 1...Bead-shaped panel, 2...Panel vibration damping material, 3
...Panel damping material test piece, 4... Steel plate or panel.

Claims (1)

[Claims] 1 A mixture of an epoxy resin, a liquid resin that is compatible with the epoxy resin and whose terminal group is a methylol group, a curing agent, and an inorganic filler, and is the sum total of the above epoxy resin and liquid resin. quantity 100
The composition is composed of 5 parts by weight to 75 parts by weight of epoxy resin, and 30 parts by weight or more of the inorganic filler based on 100 parts by weight of the epoxy resin and liquid resin. Characteristic panel vibration damping material.