JPH0664130A - Manufacture of weldable composite vibration-damping metal plate - Google Patents

Abstract

PURPOSE:To stabilize and improve weldability by removing resin between a skin metal sheet and a metal filler at the time of heat pressure welding and making the metal filler contained in an intermediate resin layer play a role of a conductive bridge between the skin metal sheets securely in the manufacture of a weldable composite vibration-damping metal plate by inserting resin containing the metal filler between two skin metal sheets and heat pressure welding the resin inserted skin metal sheets thus prepared. CONSTITUTION:A metal filler is dispersed uniformly between two skin metal sheets and resin contained is inserted therein, and the resin inserted metal sheets are heated until the viscosity of resin becomes 5X10<2>-5X10<4> poise and pressure welded. Resin cutting-out between the skin metal sheets and the metal filler, therefore, can be carried out securely by making the resin viscosity in the above-referred range at the time of heat pressure welding and also overflowing of resin can be avoided to prevent the uneven distribution of metal filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a weldable composite vibration-damping metal plate having excellent conductivity.

[0002]

2. Description of the Related Art In recent years, as awareness of environmental noise has increased, it has become stricter to prevent noises generated from various devices and buildings, and various noise prevention measures are being actively promoted. . Under such circumstances, it is widely known that a vibration-damping composite metal plate having a viscoelastic resin layer having a vibration damping property in the middle is effective for a site where a metal plate is used.

On the other hand, a conventional composite vibration-damping metal plate in which a resin layer is interposed between two skin metal plates has a drawback that resistance welding such as spot welding cannot be performed because the intermediate resin layer is an electric insulator. is there. Therefore, for applications where welding is required, a weldable composite damping metal in which conductivity is imparted between skin metal plates by dispersing and adding a conductive filler composed of metal particles to a resin layer interposed in the middle Boards are used.

[0004]

By the way, in these weldable composite vibration-damping metal plates, in order to secure stable weldability, the metal filler dispersed and added in the resin inserted in the middle is pressed and laminated. It must be evenly distributed between the latter two skin metal plates and surely contact both skin metal plates to form a conductive bridge. For this reason, various technical studies have been added from various fields.
The type, amount and size of the metal filler to be added are specified in correlation with the resin layer thickness, and further, the diameter of the metal filler to be added is made larger than the intermediate resin layer thickness, that is, the metal filler after pressure bonding. Many proposals have been made to electrically connect the skin metal plate and the metal filler by, for example, defining the flatness to provide conductivity between the two skin metal plates.

However, although these prior arts each have excellent effects, the weldability of the obtained weldable composite vibration-damping metal plate may become unstable depending on the type of resin interposed in between. Then, in that case, when the weldable composite vibration-damping metal plate was investigated in detail, there was a deviation in the distribution of the metal filler, which should be originally uniform,
The resin is caught and remains at the interface between the skin metal plate and the metal filler, and the metal filler added to the corner is in a state where it cannot fully fulfill the role of the conductive bridge, so the desired conductivity cannot be secured. It turned out that

This also means that the range of applications of the weldable composite vibration-damping metal plate has expanded further in recent years, and the types of intermediate resins that influence the adhesive strength and the vibration-damping characteristics have expanded accordingly. It is considered that, while the behavior of the resin during pressure bonding is important, the conventional technique does not give clear consideration to this point. Therefore, in order to confirm this, as a result of investigating the behavior of various resins containing a metal filler during thermocompression bonding with the skin metal plate, the viscosity of the resin once melted during thermocompression bonding falls within a certain range. When adjusting to the value within
We obtained the knowledge that the resin can be prevented from being caught and left at the interface between the skin metal plate and the metal filler, and that the distribution of the metal filler can be prevented from becoming uneven, and based on the conditions grasped by the investigation. And completed the present invention.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and it is possible to more reliably remove the resin between the skin metal plate and the metal filler at the time of heating and pressure bonding.
The metal filler contained in the intermediate resin layer can surely play the role of a conductive bridge between the skin metal plates,
An object of the present invention is to provide a method for manufacturing a weldable composite vibration-damping metal plate having stable and excellent weldability.

[0008]

In order to achieve the above object, the present invention has the following constitution. That is, the method for producing a weldable composite vibration-damping metal plate according to the present invention is such that a resin containing a metal filler uniformly dispersed therein is inserted between two skin metal plates and the viscosity of the resin is 5 × 10 ^2. ~ 5 x
It is characterized by heating to a temperature of 10 ⁴ poise and pressure bonding.

[0009]

The function of inserting the resin containing the metal filler evenly dispersed between the two metal plates and pressing them together as a single weldable composite vibration-damping metal plate is performed by using a pressure roll or the like. At the same time that the resin is once in a molten state, a pressure is applied to the upper and lower two skin metal plates to perform thermocompression bonding. At this time, the metal filler contained in the resin is pressed by the two upper and lower skin metal plates, and in the ideal state, the resin existing between the metal filler and the skin metal plates is removed (resin cutting), and A conductive path is formed in contact with the inner surface of each skin metal plate. Therefore, if the fluidity of the resin at the time of thermocompression bonding is good, the resin can be effectively cut by pressing, and if the residual rate of the resin at the interface between the skin metal plate and the metal filler after thermocompression bonding is low, Is ensured, the conductivity between the skin metal plates is stable, and the weldability is excellent.

However, the viscosity of the resin during thermocompression bonding is 5 × 10 5.
If it is higher than ⁴ poise, the resin surrounding the metal filler is hard and has low fluidity, so even if pressure is applied to the two upper and lower skin metal plates, the space between the metal filler and the skin metal plate will be high. The resin cannot be cut, and the conductivity between the skin metal plates becomes unstable.

On the other hand, when the heating temperature is adjusted so that the viscosity of the resin at the time of crimping is not more than 5 × 10 ⁴ poise, the fluidity of the resin is increased and the resin cutting between the metal filler and the skin metal plate is increased. Will be easier. However, if the viscosity of the resin is lower than 5 × 10 ² poise in order to enhance the fluidity, the resin will be in an over-melted state and maintain high fluidity even after pressure bonding. Even if it is possible to temporarily contact the skin metal plate with the metal filler,
Immediately after the pressurization is released, the resin again wraps around between the skin metal plate and the metal filler to hinder the conductivity. Furthermore, in the over-melted and low-viscosity resin layer, the metal filler that has been uniformly dispersed and contained is accompanied by and flows with the resin movement during pressurization to cause segregation, and its distribution state is The unevenness is likely to occur, resulting in unstable conductivity between the skin metal plates.

Here, in the present invention, a resin containing a metal filler uniformly dispersed therein is inserted between two skin metal plates, and the viscosity of the resin is 5 × 10 ² to 5 × 10 ⁴ poises. Since it is heated to a temperature and pressure-bonded, it is possible to prevent the resin from being caught and left at the interface between the skin metal plate and the metal filler, and it is also possible to prevent the distribution of the metal filler from being unbalanced. It is possible to obtain a weldable composite vibration-damping metal plate having stable conductivity and excellent weldability.

The metal filler to be contained in the above-mentioned resin is made of a metal having good conductivity, and has a particle size such that the flatness after pressure bonding (particle size before pressure bonding / resin layer thickness after pressure bonding) is 1.2 or more. Metal particles are used.

[0014]

EXAMPLES Examples of the present invention will be described below. Example 1 Between two skin steel plates made of steel strip having a plate thickness of 0.4 mm and a plate width of 914 mm, Ni particles made of a thermoplastic resin of polyolefin and having an average particle size of 65 μm were used as a conductive filler to obtain 3.0 volume. %, A resin sheet containing the particles evenly dispersed therein was inserted, and the sheets were thermocompression bonded by a pair of compression rolls having a built-in heating means, to fabricate a testable weldable composite damping steel plate A.

In the thermocompression bonding, the Ni particles added to the resin have an average flatness (particle size before pressure bonding / resin layer thickness after pressure bonding) of 1.2 or more, and an average value of 1.3. The target value of the resin layer thickness is set to 50 μm and the roll gap of the crimping roll is set, while the heating temperature of the crimping roll is changed from the low temperature side to the high temperature side in order to change the resin viscosity during the crimping from the high viscosity side. Thermocompression bonding was continuously performed while shifting to the low viscosity side, and the thermocompression bonding conditions were different in the longitudinal direction.

Then, it is possible to clearly understand the heating temperature which is sequentially changed from each portion in the longitudinal direction of the obtained testable weldable damping steel sheet A, that is, the viscosity of the resin in the molten state at that temperature. Samples were taken out from the No. 1 to No. 6 parts that had different thermocompression bonding conditions, and the weldability of the welding test pieces collected from these samples was compared by spot welding. went. In spot welding, two welding test pieces with a width of 30 mm and a length of 100 mm (thickness: approximately 0.8 mm) are stacked, and the stacked ends are weld current 8.5 kA, energization time 20 cycles, electrode pressure
Spot welding was performed under the welding condition of 200 kgf, and the weldability was comparatively evaluated by the incidence of welding defects. The results are shown in the graphs of [Table 1] and [Fig. 2].

[0017]

[Table 1]

On the other hand, when observing the state of the molten resin pool (resin bank) formed on the inlet side of the pair of pressure-bonding rolls during the heat-pressure bonding, the heating temperature was raised to increase the resin viscosity at the time of pressure bonding to 5 × 10 ^2. It was confirmed that when the poise was made lower than the poise, the generation of the resin bank was increased and the movement of the Ni particles became conspicuous with the flow of the molten resin.

Therefore, regarding this weldable damping steel plate A,
No. 1 with resin viscosity of 5 × 10 ² poise or more at the time of thermocompression bonding
The distribution state of Ni particles in the width direction of each of the sample 3 and the sample No. 6 in which the resin viscosity was made lower than 5 × 10 ² poise by raising the heating temperature was investigated. The results are shown in the graph of FIG. In the graph, curve A3 shows the results of No. 3 trial material, and curve A6 shows the results of No. 6 trial material.

As shown in the graphs of [Table 1] and [FIG. 2], the resin viscosity during thermocompression bonding was set within the range of 5 × 10 ² to 5 × 10 ⁴ poise satisfying the conditions of the present invention. No welding defects were observed in No. 2 to No. 4, whereas in No. 1 with high viscosity exceeding 5 × 10 ⁴ poise and 5 × 10 ² poise. With No. 5 to No. 6 having lower viscosity, welding defects occurred at a high rate in all cases.

When the cross sections of the welded test pieces were observed with a microscope, No. 2 to No. 2 satisfying the conditions of the present invention were obtained.
In No. 4, the Ni particles F in the resin R are deformed under pressure to have a predetermined flatness while the Ni metal particles F in the resin R are pressed and deformed as shown in (a) of FIG. The resin R remaining at the interface with the plate S was very small, that is, the resin cutting was effectively performed, and the two skin metal plates S were surely in contact with each other.

On the other hand, in the case of No. 1 in which the resin viscosity at the time of thermocompression bonding is higher than the conditions of the present invention, the Ni particles F have a predetermined flatness as illustrated in FIG. Despite being deformed under pressure, the resin R was caught and remained at the interface with the skin metal plate S, and was blocked by the resin R, making contact with the skin metal plate S uncertain. . Also,
This tendency was more noticeable as the resin viscosity increased. This is because the resin surrounding the Ni particles is hard and has low fluidity, so even if the Ni particles are deformed by the pressure applied during pressure bonding, the resin existing between the Ni metal and the skin metal plate is not extruded and captured. That is, it is presumed that the resin cannot be cut, and the resin remains as it is.

On the other hand, in No. 5 to No. 6 having a resin viscosity at the time of thermocompression bonding lower than that of the conditions of the present invention, the resin cutting is easy and the Ni particles F and the skin metal plate S are brought into contact with each other more reliably. However, as illustrated in the same figure (c), the resin R remains at the interface with the skin metal plate S,
The contact between the Ni particles F and the skin metal plate S was uncertain. This is because if the heating temperature is raised to lower the resin viscosity in order to increase the fluidity of the resin, the resin will be in an over-melted state and will maintain high fluidity even after pressure bonding. Cut the resin and temporarily cut the surface metal plate and N
It is presumed that even if the i particles can be brought into contact with each other, the resin again wraps between the skin metal plate and the Ni particles immediately after the pressure is released.

Further, when the resin viscosity is excessively reduced, the Ni particles largely fluctuate from the uniform distribution state at the time of addition and segregation occurs, and as shown by the curve A6 in the graph of FIG. The distribution state is uneven in the width direction,
This also makes the weldability unstable. On the other hand, when the resin viscosity is within the appropriate range,
Excessive fluidization of the resin could be avoided, and as shown by the curve A3 in the graph, the Ni particles maintained a substantially even distribution state as in the case of addition.

As described above, in the weldable vibration-damping steel plate satisfying the conditions of the present invention, the Ni particles contained in the intermediate resin layer can surely play the role of the conductive bridge between the skin metal plates. In addition, it is possible to prevent the distribution of the Ni particles from being biased, so that the conductivity between the skin metal plates is stable and the weldability is excellent.

[Example 2] While a steel strip S'having a plate thickness of 0.4 mm and a plate width of 400 mm which has been subjected to galvannealing is prepared as a skin steel plate, it is different from the resin of [Example 1] A resin sheet made of two types of polyolefin-based thermoplastic resins R1 and R2 having different characteristics described above and a resin sheet made of a polyester-type thermosetting resin R3 were prepared. Also, these three kinds of resins R1, R2, and R3, as in [Example 1], contain Ni particles having an average particle size of 65 μm as a conductive filler evenly dispersed at 3.0% by volume. did.

Then, the above resin sheet is inserted between two skin steel sheets S ', and they are thermocompression-bonded with a pair of pressure-bonding rolls having a built-in heating means, and the resin R1 is used as an intermediate resin layer. Weldable damping steel sheet C having resin R2 as an intermediate resin layer, and welding damping steel sheet D having resin R3 as an intermediate resin layer were manufactured.

In the thermocompression bonding, the Ni particles have a flatness of 1.2 or more (average 1.
The target value of the intermediate resin layer thickness is 50 μm so that the value of 3) is obtained.
As a result, while setting the roll gap of the pressure-bonding roll, the resin temperature during pressure-bonding is selected so that different weldable damping steel plates are obtained within the scope of the conditions of the present invention, and the heating temperature by the pressure-bonding roll is selected to perform heat pressure bonding. It was For comparison, the resin viscosity at the time of thermocompression bonding deviates from the condition of the present invention, and the resin is pressure-bonded. Weldable damping steel plate B'having resin R1 as an intermediate resin layer and resin R2 as an intermediate resin layer. Weldable damping steel plate C'and weldable damping steel plate D'with resin R3 as an intermediate resin layer were also manufactured.

Then, for each of the obtained weldable and vibration-damping steel plates, comparative evaluation of weldability was carried out by a welding test under the same conditions as in [Example 1]. The results are summarized and shown in [Table 2]. In addition, B-1 to B-5 in [Table 2]
Examples are the weldable damping steel plates B and C-1 of the present embodiment in which the resin R1 is an intermediate resin layer. The examples are the weldable damping steel plates C and D-1 of the present embodiment in which the resin R2 is an intermediate resin. Shows the results for each of the weldable vibration damping steel plates D of this embodiment using resin R2 as an intermediate resin. Further, B'-1 example is a weldable damping steel sheet B ', C'-1 to C'-2 examples of comparative examples in which resin R1 is an intermediate resin layer,
Weldable damping steel plates C'and D'-1 to D'-2 of the comparative example using resin R2 as the intermediate resin are the results of the weldable damping steel plates D'of the comparative example using resin R3 as the intermediate resin. Indicates.

[0030]

[Table 2]

As shown in Table 2, the resin viscosity during thermocompression bonding, and that of Comparative Example A was a high viscosity of greater than 5 × 10 ⁴ poise (B'-1), from 5 × 10 ² poise In the comparative examples (C'-1, C'-2, D'-1, D'-2) having low viscosity,
Except that the C'-1 case had a slightly low incidence of 10% or less,
Weld defects occurred at a high rate of 10% or more. On the other hand, in the case of the present embodiment, no occurrence of welding defects was observed, which means that the present invention is effective even when resins having different characteristics are used as the intermediate resin layer, and has an excellent effect. It was confirmed that it was possible to obtain.

Here, the evaluation results in the above-mentioned [Example 1] and [Example 2] are summarized in the graph of [Fig. 1] in terms of the relationship between the resin degree and the heating temperature during thermocompression bonding. In addition,
In the same graph, the plots with white outlines show examples in which no welding defects were observed, the plots with black symbols show examples in which welding defects occurred, and the two-dot chain line indicates the The upper limit and the lower limit of the invention conditions are shown.

As shown in the graph of FIG. 1, in each of the examples where the resin viscosity at the time of thermocompression bonding was set within the range satisfying the conditions of the present invention, no welding defects were observed, but in the range exceeding the upper limit value. And welding failure has occurred in each of the regions where the lower limit value has not been reached. From this, the limiting conditions of the present invention are appropriate, and by satisfying the conditions, weldability is stable and excellent. It turns out that a metal plate can be obtained.

[0034]

As described above, according to the method of the present invention, the resin between the skin metal plate and the metal filler can be more surely removed at the time of thermocompression bonding, and the resin is contained in the intermediate resin layer. The metal filler can surely play the role of the conductive bridge between the skin metal plates, and the uneven distribution of the metal filler can be prevented, so that the weldability is stable and excellent. A vibrating metal plate can be manufactured.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between resin viscosity, heating temperature, and occurrence of welding defects according to an example of the present invention.

FIG. 2 is a graph showing a relationship between a resin viscosity and a welding defect occurrence rate in Example 1 of the present invention.

FIG. 3 is a graph showing the relationship between the resin viscosity and the distribution state of the metal filler in the plate width direction according to Example 1 of the present invention.

FIG. 4 is a diagram schematically showing a microscopic observation result of a cross section of a weldable damping steel sheet according to Example 1 of the present invention.

Claims (1)

[Claims] 1. A resin containing a metal filler uniformly dispersed therein is inserted between two skin metal plates and heated to a temperature at which the viscosity of the resin is 5 × 10 ² to 5 × 10 ⁴ poises. A method for manufacturing a weldable composite vibration-damping metal plate, which comprises crimping.