JPH0699562A - Manufacture of composite vibration-damping steel plate - Google Patents

Abstract

PURPOSE:To obtain a method for manufacturing a composite vibration-damping steel plate having stable performance without irregularity in a cured state of intermediate resin and without aging change of the performance by press- bonding two skin steel plates to an intermediate resin layer and then supplying a current between the plates. CONSTITUTION:A composite vibration-damping steel plate is manufactured by the steps of adding predetermined conductive filler to mixture solution of saturated polyester resin and isocyanate curing agent, agitating them to obtain liquidlike mixture, then coating a cold rolled steel with it by using a roll coater, then thermally drying it, and then thermally press-bonding it by a heat medium roll. The thus obtained plate is conducted with a predetermined current density between the plates by a current supplying roller, then cooled to about an ambient temperature, and wound in a coil state by a coiler. Thus, performance such as aging change, irregularity of the plate can be reduced, and the plate which can be used widely as vibration.noise preventive material and has excellent heat resistance, spot weldability can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite type vibration-damping steel sheet in which a thermosetting resin is interposed between two steel sheets, which is particularly excellent in heat resistance and spot weldability and has excellent performance. Manufacturing method of composite vibration-damping steel sheet that can be widely used as a vibration / noise suppression material in parts that require heat resistance and spot weldability, such as automobiles, construction, electrical materials, etc. Regarding

[0002]

2. Description of the Related Art In recent years, with the widespread use of industrial machines and household electric appliances, noise and vibration generated from various devices have come to be regarded as a problem from the viewpoint of health and hygiene or environmental protection.
In particular, the spread of transportation equipment such as automobiles is remarkable, and the noise generated by them is a serious social problem.

As one of the countermeasures against this, there is the use of a damping steel plate or the like. The vibration-damping steel plate uses a vibration-damping alloy, the two-layer type (unconstrained type) in which the vibration-damping material is attached to one side of the steel plate,
Three-layer type (restraint type) with core resin sandwiched between two steel plates
Etc., and are being adopted in a wide range of fields. In particular, the composite restraint type vibration damping steel plate (hereinafter simply referred to as a vibration damping steel plate) attenuates vibration by utilizing internal friction due to shear deformation of the viscoelastic material of the intermediate layer, and is the most vibration damping type among the above. In addition to being excellent in performance, there is an advantage that secondary processing such as pressing can be performed as it is, and it can be handled in the same manner as ordinary steel plates.

By the way, most of the development themes relating to the manufacturing method of the vibration-damping steel sheet using the most general thermosetting resin as the resin of the intermediate resin layer for the vibration-damping steel sheet are related to the heat pattern, Almost limited to heat pattern control methods and line configurations. However, since the thermosetting reaction characteristics differ from resin to resin, strict control is required, and even if strictly controlled, it is difficult to complete the curing reaction in the line, and there are problems such as aging phenomenon. The problem was inherent.

On the other hand, the inventors of the present invention, as an intermediate resin for a vibration-damping steel sheet having a good balance of vibration-damping properties, adhesiveness, durability, heat resistance, etc., have a weight average molecular weight of 5,000 or more and a softening point of 50 ° C. or more.
A resin for a composite type vibration damping steel sheet comprising a saturated copolyester at 150 ° C. and a crosslinking agent for a polyvalent isocyanate compound has been developed, which is disclosed in JP-A-64-48813.

However, when a thermosetting resin such as an isocyanate cross-linked copolymerized saturated polyester is used, the control of the curing reaction in the manufacturing process is extremely complicated, and it is necessary to control the heat pattern according to the line speed. Become. Even if the process can be strictly controlled, it is impossible to manage the cured state of the resin without variation. Since the hardened state is directly reflected on the performance of the vibration-damping steel sheet, if the hardened state varies, the performance varies. In addition, depending on the resin, the curing reaction gradually proceeds at room temperature, and if the reaction is not completed within the manufacturing process, the performance immediately after manufacturing changes over time due to storage at room temperature, a so-called aging phenomenon occurs. However, we can not guarantee the performance when this steel sheet is actually used as a part,
Alternatively, there is a problem that it may deviate from the guaranteed range.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems, and in the production of a composite type vibration-damping steel sheet using a thermosetting resin as an intermediate resin, variations in the cured state of the intermediate resin and changes with time in performance are caused. The present invention provides a manufacturing method having stable performance.

[0008]

In order to achieve the above object, the present invention is a method for producing a composite type vibration-damping steel sheet in which a thermosetting resin layer containing a conductive filler is interposed between two steel sheets. In the method of manufacturing a composite vibration-damping steel plate, the two skin steel plates and the intermediate resin are pressure-bonded to each other, and then an electric current is passed between the skin steel plates.

[0009]

[Function] Basically, the manufacturing of the vibration-damping steel sheet using the thermosetting resin as the intermediate resin is the coating of the resin solution, the drying, the preheating,
The process consists of heating and compression and cooling. In order to complete the curing reaction in the production line, control of heat input in the drying and preheating steps and heat input in the thermocompression bonding step becomes extremely strict. Also, when the resin is changed or the line speed is changed, it is necessary to control the heat pattern accordingly. For the type of resin whose curing reaction is slow, it is necessary to take measures on the facility side, such as lengthening the preheating furnace or installing a larger curing furnace after pressure bonding. The curing reaction rate of the resin can be adjusted to some extent by using a catalyst, but the heat pattern control for each line speed is still required. Further, when a catalyst is used, the curing rate tends to change from lot to lot, and there are problems such as variations in products.

From the above, it is difficult to strictly control the cured state in the production line, although it can be controlled to some extent. Therefore, a method for completing the curing reaction after the pressure bonding step is required. On the other hand, in order to give the vibration-damping steel plate spot weldability equivalent to that of a normal steel plate,
It is common practice to mix a conductive filler into the intermediate resin. In spot welding of vibration-damping steel plates, the conductive filler in the intermediate resin forms a current-carrying circuit, which generates Joule heat, heats the filler and the resin around the filler, and further eliminates the resin by pressing the welding electrode. It becomes possible by contact with the accompanying skin steel plate. The present invention applies this principle to form an electric circuit between two steel plates through a filler by passing an electric current between the skin plates of the vibration-damping steel plate after pressure bonding, and the heat generated by this is generated by the resin. It is used for the curing reaction.

The energizing condition cannot be uniquely determined because it depends on the curing reaction characteristics of the intermediate resin, but in general, it is not necessary to set it to a high temperature such as during welding, so at a current density of 50 A / cm ² or more. I wish I had it. In the manufacturing line, energization may be performed between any steps as long as it is after the crimping step, but from the viewpoint of thermal efficiency, it is desirable before the cooling step. Further, there is no problem even if it is outside the production line, and considering the stabilization of the cured state, it is rather preferable after the coil or sheet is commercialized. The energizing time also differs depending on the curing reaction characteristics of the resin, so it cannot be uniquely determined, but in the case of energizing after commercialization,
When it is at least the above value, the cured state of the resin is sufficiently uniform, which is preferable.

According to the present invention, the conductive filler to be mixed in the intermediate resin layer is not particularly limited, but metal powder such as iron, stainless steel, nickel, copper having a particle diameter of not less than the thickness of the intermediate resin layer, It is desirable to add 0.5 vol% or more in the intermediate resin. More preferably, 0.5 to 3.0 vol% of metal powder having a ratio (d / t) of particle diameter (d) to resin thickness (t) of 1.0 to 2.5 is blended. If it is out of these ranges, spot weldability, vibration damping performance, adhesive performance, etc. may deteriorate. On the other hand, if the blending amount is less than 0.5 vol%, the heat generated during energization after pressure bonding will be insufficient and the resin will not be sufficiently cured.

According to the present invention, since the heat input to the thermosetting resin is Joule heat, the manufacturing line length can be shortened as compared with the conventional heating furnace type, and the curing reaction can be stabilized before the product is shipped. It will be possible to complete it, and it will bring significant effects in terms of both cost and quality. Also,
It also eliminates the need for detailed handling according to the manufacturing conditions (line speed), which has the effect of facilitating operation.

[0014]

EXAMPLES The present invention will be specifically described below based on examples. First, the damping steel plate of this example was manufactured by the following procedure. A predetermined amount of the filler as shown in Table 1 is added to the mixed solution of the saturated polyester resin and the isocyanate curing agent,
The mixture was thoroughly stirred with a mixer to obtain a liquid mixture. This liquid mixture is applied to a degreased pre-treated cold rolled steel strip having a thickness of 0.5 mm by using a roll coater, and then the steel strip is carried into a drying oven at 150 ° C. and heated and dried for 2 minutes, and then, Other steel strips 1
A composite type vibration damping steel plate was manufactured by thermocompression bonding with a heating medium roll under the conditions of 80 ° C. and a linear pressure of 20 kgf / cm. The final intermediate resin thickness at this time was set to 50 μm. The composite type vibration damping steel plate thus obtained was energized between the skin steel plates at the current density shown in Table 1 by a power feeding roller, then cooled to about room temperature by a water cooling type cooling roll and air cooling, and coiled by a coiler. I wound up.

In addition, as a comparative example, a device in which power was not supplied by the power feeding roller was also manufactured. For each of the steel sheets of Examples 1 to 3 and Comparative Examples 1 to 6 manufactured in this way, the following items were measured. Curing degree After the lamination and adhesion, the resin was peeled off, and the gelling rate was calculated from the residual amount after the intermediate resin was extracted with acetone using a Soxhlet extractor for 24 hours, and was taken as the curing degree.

Spot Weldability Direct spot welding was performed under the conditions of a pressing force of 200 kgf, a current of 8 kA, an energization of 8 cycles, and an electrode tip 8R ball, and the welding success rate (%) was evaluated when the number of samples n = 100. Damping property It was processed into a size of 20 mm × 300 mm, and the loss coefficient (η) at 1000 Hz was measured by the mechanical impedance method.

Adhesiveness The adhesive strength (T-type peel strength) between the steel sheet and the intermediate resin is JIS K-
Measured according to 6854. The results are shown in Table 1.

[0018]

[Table 1]

As is clear from this table, the respective performances of the respective samples had satisfactory values, including the change with time after one month of the production, in Comparative Examples 1, 2 and 3.
In Nos. 3 and 5, deterioration of spot weldability and vibration damping property due to aging was large, and in Comparative Examples 4 and 6, there were problems such as low T-type peel strength. On the other hand, in each of the examples, the spot welding success rate was 100%, and it was confirmed that the variation was reduced.

[0020]

As described above, according to the method for manufacturing the composite type vibration damping steel sheet of the present invention in which the thermosetting resin is used for the intermediate layer, it is possible to reduce the time-dependent change and variation of each performance of the steel sheet. As a vibration and noise prevention material, heat resistance that can be widely used in the automobile industry, civil engineering and construction industry, electrical industry, etc.
There is an effect that it is possible to obtain a composite type vibration damping steel sheet having excellent spot weldability.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F16F 15/02 Q 9138-3J (72) Inventor Seiji Sakamoto 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel (72) Inventor Hidetaka Suganabe 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Co., Ltd.

Claims (1)

[Claims] 1. A method for manufacturing a composite vibration-damping steel sheet in which a thermosetting resin layer containing a conductive filler is interposed between two steel sheets, and two skin steel sheets and an intermediate resin layer are pressure-bonded to each other. After that, a method for producing a composite vibration-damping steel sheet is characterized in that an electric current is passed between the skin steel sheets.