JPS61190547A - Manufacture of vibration-controlling and sound-insulating high polymer material formed body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] industrial 1 The present invention relates to a method for manufacturing vibration damping and sound insulation materials.

In general, coatings consisting of mineral fillers bonded with resinous or polymeric materials are used on metal sheet structures, especially to reduce noise, which is increased due to the mutual porosity of the structure. . Generally, these coatings are referred to as damping materials and are applied as paints to the desired surface or as sheets with adhesives. It is also known that such coatings provide some degree of sound insulation.

In particular, the sound insulation efficiency of these materials is related to the thermoelastic or viscous properties of the resinous or polymeric binder, but also the selection of the mineral filler is important.

Polymers of vinyl acetate and related copolymers are known to have unusually high internal damping properties and are therefore known to be advantageous in the formulation of such materials.

The temperature range over which these materials are effective in providing sound insulation is related to their softness. The softness of materials containing vinyl acetate polymers and copolymers is easily controlled by using plasticizers such as those used with nitrocellulose.

One example of such plasticizers are low molecular weight heptatarate plasticizers, as they are generally known to be compatible with vinyl acetate polymers and copolymers.

Because vinyl acetate polymers and copolymers are readily soluble in polar solvents, damping materials made from such polymers and copolymers are generally used as paints for direct application or as solutions for casting sheet materials. Manufactured as. Some vinyl acetate polymers and copolymers can be dispersed in water as emulsions which can also be used in the production of damping materials in the form of paints and cast sheets.

Problems to be Solved by the Invention However, heretofore sheets of damping material or other shaped bodies have been produced from mineral-filled vinyl acetate polymers by thermoplastic processing, e.g. rolling, of these polymers. That had not been done. This is because the melting properties of these polymers, together with high filler loadings, have not been considered advantageous for the production of thick sheets or other shaped bodies by this method.

Means for Solving the Problems According to the present invention, a vinyl acetate polymer material, a filler, and a plasticizer are mixed, and then this mixture is subjected to thermoplastic processing to produce a molded article. A method for manufacturing a polymer material molded body for vibration damping and sound insulation is obtained.

Furthermore, the present invention provides, in the method, (a) the following components: 24% by weight of polyvinyl acetate as the vinyl acetate polymer material; 6% by weight of butylbenzyl phthalate as the plasticizer; 1% by weight of the lubricant; Blend 53 grams of slate powder as part of the filler; and 16" IL of mica as the remainder of the filler until well dispersed; transfer the blended mixture to a mixer; heated to a temperature of 170°C to 180°C: and (C) this heated mixture ft60°C to 120°C
The method comprises rolling at a roller temperature of .

By blending a mixture that can be rolled and subsequently producing a shaped body such as a sheet by thermoplastic processing, the shaped body obtained can be compared with similar products produced by painting or casting processes. It was found that it has a sound insulation performance that is comfortable to wear and has a large sound insulation performance. This is believed to be due to the fact that thermoplastic processing results in a high degree of dispersion of the mixture components in the molded body. Furthermore, thermoplastic processing is performed using solvents (
It has the advantage that its presence does not have to comply with anti-pollution regulations) or the use of expensive, energy-intensive water for its removal. Modified polyvinyl acetate is non-toxic.

The thermoplastic processing can be rolling, extrusion, or compression molding, but rolling is advantageous for producing sheet-like molded bodies.

It has been found that the shaped body can be directly rolled as a thin unlined sheet of around 600 μm.

Such sheet materials have a number of advantages over backed materials in terms of ease of handling and conversion, for example by laminating, cutting or applying pressure sensitive adhesives.

Vinyl acetate polymers, generally having a molecular weight of 60 to K80, can be homopolymers of vinyl acetate or copolymers of vinyl acetate and, for example, maleate or crotonic esters. This polymer is
The selection depends on the particular desired damping characteristics.

The extender resin can be mixed with the vinyl acetate polymer in a weight ratio of up to 1:5. The resin may be another vinyl resin, oxidized bitumen or pitch, or a mixture thereof with an ethylene polymer.

Preferably, the plasticizers are those commonly used in the production of nitrocellulose, ie highly solvating plasticizers, for example phthalate esters, such as dibutyl phthalate or butylbenzyl phthalate.

The amount of plasticizer used depends on the type of damping material to be manufactured.
and the temperature range in which the damping material needs to operate. Generally this amount is 4 to 9 times the total composition.

Advantageously, the filler consists of a mixture of clay and mica, with a filler content of 50 to 80% by weight of the total composition.

It has proven advantageous to include additives for lubricating, stabilizing and/or coloring purposes in the composition.

These components of the mixture are selected and selected such that a desired fracture performance of the compact is obtained and certain processing properties for the rolling operation are obtained when this thermoplasticization process is used. It is blended.

The breakage performance detailed below is based on British Industrial Standards (8riti).
sh 5 standard) AU 125: 19
It can be evaluated using the method described in 66. The noise attenuation rate at room temperature may be expected to be between sdbl and 2 odbl for a material having a weight of IKg/rl-12.

Workability in rolling processing is determined by thermodynamics (therm and m
mechanical) analysis and indentation test. The latter is described in British Industrial Standard No. 3260. Preferred compositions have a glass transition point below 10°C and soften gradually up to 200°C. The indentation hardness value is Q
, 5 rrm to l, Q rrm (0.02 in% to 0.04 inch) (25°C).

If thermoplastic processing is extrusion processing instead of rolling processing,
A shaped body of tubular cross-section can be extruded and subsequently cut and expanded to produce, for example, flat sheets. This only requires a relatively simple mold structure.

11th standing In the following, the invention will be explained in detail with reference to drawing examples.

Example 1 Mix the following ingredients together (in weight A%):
Vinyl hexate (PVA) (molecule 11 to 70) 24'I = butylbenzyl phthalate (plasticizer) 6th lubricant
1 Tislate powder (mineral filler) 53% mica (mineral filler)
Blend the 16 selected ingredients until well dispersed. The blended materials are then transferred to a high-intensity or continuous mixer where one
Heat to a temperature within the range of 190°C to 190°C.

This heated material is then fed to a calender or bank of calenders operating in a 20-mile mode. Advantageously, the calender roll temperature is set at a temperature below the temperature of the heated mass. Typical temperatures are in the range 60°C to 120°C, preferably 60°C to 80°C.

The gap between the calender rolls is set accordingly to the sheet thickness required to obtain a weight of IKg/rr 120.

The sheet' discharged from the calender is cooled and wound into rolls for further processing or cut into panels of the desired dimensions. The roll of sheet material can be used directly or converted to a pressure sensitive adhesive roll or sheet if desired.

In one experiment according to this example, the blended materials were heated to 180°C in a continuous mixer and fed to a two roll calender, with roll temperatures set at 80°C and 60°C. Calendar speed was 1 om/min. The resulting sheet was cut and cut into panels.

These panels are based on British Industrial Standard AU:125:1966.
Tested by. These had a noise attenuation rate of 16 dB/sec at 16°C. The damping rate of the comparative material produced by the casting method is 11 dB/sec at the same temperature.

Example 2 A sheet was prepared using the method of Example 1 with a weight of 1.25 Kg/m
2 and a thickness Q of 5 mm, and tested for suitability as a damping sheet material for use in automobiles. The properties of this material and the test methods applied are detailed below with reference to the accompanying figures 1 to 7.

In the drawings: FIG. 1 is a diagram showing the variation with temperature of the elastic modulus and dynamic loss rate of unmodified PVA and the material of Example 2; FIG. Fig. 3 is a chart showing the attenuation rate by Geiger plate test in comparison with temperature; Fig. 4 is a chart showing the
FIG. 5 is a chart showing the composite dynamic loss factor as compared to temperature according to a complex modulus test; FIG. Figure 6 is a diagram showing the composite dynamic loss factor compared to the frequency of vibration (Hz); and Figure 7 is a diagram showing the various fixing methods of sheet material. 2 is a chart showing the attenuation rate in comparison with temperature, and shows the effect of a fixing adhesive.

It is assumed that the damping materials adhere to the surface of the vibrating panel, emphasizing the physical properties of these damping materials that are important to their function. The basic condition is that a maximum amount of vibrational energy is removed from the panel and that the extracted energy is then converted as much as possible into an almost harmless form, for example heat.

The simple case of a single motion of the panel would induce a static deformation of the damping material. The ratio of the applied stress (σ) to the resulting strain (ε) determines the elastic modulus (E) of the material, or σ = Eε.

Therefore, the damping material must have a high modulus of elasticity in order to maximize the stresses necessary to create distortion, and therefore the panel energy utilized.

When a dynamic load in the form of an oscillatory motion is applied to a material, internal friction (viscous losses) resists the stress present. Taking this into account, the elastic modulus needs to be expressed as a complex equation. That is, E* = E' + jE. However, E* - complex modulus E' = modulus of elasticity E' = loss modulus j = r The dynamic loss modulus η of the material, which is a property that can be easily measured, is The ratio E''/E' is defined, and thus the above equation can be rewritten: gun = E'(1 + jη) By the way, it is important for the damping material not only to have a large modulus of elasticity, but also to reduce its loss. The elastic modulus or dynamic loss factor must be large in order to maximize the energy conversion due to internal friction. This type of material is called viscoelastic.

Under certain conditions, PVA exhibits the desired viscoelastic properties and is non-toxic.

Like most plastics, PVA undergoes a phase change when its temperature increases. At low temperatures, it is hard and brittle like glass. At a constant temperature, i.e. Above the freezing point, it gradually (softens), but still retains the properties of a solid material through a temperature range known as the 1 transition phase. As the temperature increases further, it weakens significantly. It begins to flow freely at the very edge and exhibits bimb behavior until it liquefies in the true sense of the term.

In the transition phase, the material maintains its toughness and exhibits viscoelastic properties. When it is deformed and therefore subjected to stress (the modulus of elasticity determines the magnitude of the stress), molecular rearrangement processes reduce the stress and the strain remains unchanged. This converts most of the molecular energy into heat. (Dynamic loss rate is a measure of a material's energy conversion ability).

FIG. 1 shows the variation of the elastic modulus and dynamic loss rate of unmodified PVA as a function of the main operating parameter, namely temperature. 1 transition phase is manifested by a sharp decrease in the elastic modulus (in the image of slow softening) and an increase in the dynamic loss rate passes through a maximum value.

The greatest effect as a damping material is at a temperature at which both the elastic modulus and dynamic loss rate are large, that is, 50°C to 60°C. PVA alone is of little practical use because its effective temperature range is not only extremely narrow but also does not encompass the standard room temperatures encountered in the end use.

Fortunately, the location and size of the effective range can be greatly improved through the selective use of plasticizers and fillers.
It's embarrassing. This also has the effect of widening this phase, ie making the slope of the elastic loop more gradual and widening the dynamic loss rate peak. The latter effect can be enhanced by adding fillers.

However, the maximum value of the dynamic loss rate decreases as the width of the peak increases, so there is a compromise between the maximum damping rate and the middle of the effective temperature range.

The formulations of Examples 1 and 2 are adapted so that the highest decay rates are obtained at standard room temperature. FIG. 1 represents the variation of the elastic modulus and dynamic loss rate of this material with temperature. PVA
The effect of the additive on can be clearly seen by comparing with the curve of the base polymer. 0-30
The high values of elastic modulus and dynamic loss factor in the °C range indicate the suitability of the standard product as a damping material for indoor conditions. Other temperature ranges can be provided by correspondingly developing the formulation.

The basic required performance of a damping material is a measure of its performance, and therefore judgments can be made from its effectiveness in the field. When considering installation performance, it is important to understand that the effectiveness of a damping material is not only determined by the properties of the product itself, but also depends on the panel to which it is installed. The effectiveness of a damping material may depend on the inherent damping of the panel, in which case a particular material may be more effective at damping a panel with very little damping than a panel that already has some damping. It has a great effect. Performance also depends on the mode or mode shape of the panel's vibration under operating conditions. The damping material is
Because its energy absorption effect is associated with bending stress, it becomes more effective as the mode shape of the panel becomes more pronounced. (The mode shape is represented by the panel shape and boundary conditions).

Following this point, if the panel is only partially coated with damping material, its performance can depend on its position relative to the mode shape of the panel, i.e. good results will be This can be obtained if the entire surface of the largest weld is covered with wadding, rather than being placed near the node points.

Therefore, even though the elastic modulus and dynamic loss factor of this damping material are known for a suitable frequency and temperature range, this cannot be taken as a measure of its performance when installed in a nosenel. Can not. In very simple cases it is possible to determine the mounting performance theoretically. Such calculations form the basis for laboratory measurements of dynamic loss modulus and elastic modulus of non-rigid materials. These materials, of which Example 2 is one example, were tested by mounting them on a simple shaped steel par. However, the structure and boundary conditions of a typical vehicle body panel are far from simple, so the only accurate measurement of combined panel and damping material performance is through direct measurement of the composite response.

In order to establish standard performance specifications and test the relative effectiveness of various materials, easily reproducible laboratory tests need to be available.

A large number of such tests exist, each emphasizing specific aspects, such as speed of testing, compatibility with specific materials, and the ability to measure performance variations with frequency/thickness/temperature. have Sample forms and test methods can each be divided into two categories.

Sample form: a) Sample mounted on a metal plate for support at nodal points and vibration at a specific resonant frequency.

b) A sample in the form of a simple par, or mounted on a metal par, clamped at one/both ends to enable measurements to be made over a range of resonant frequencies.

Test method: a) Attenuation rate measurement method: remove the external excitation force at the resonant frequency,
And the amplitude attenuation is measured in units of dB/sec.

b) Frequency Response Measurement Method Two variable frequency sinusoidal forces are applied to the sample and the amplitude of the vibration is plotted as a function of total frequency. The dynamic loss factor for a particular common frequency is obtained from the position and width of the resonant peak.

The attenuation rate and dynamic loss rate have the following relationship: η=D/s, 7/7f However, D = attenuation rate (dB/sec) f=resonant frequency (H2) Three standard tests are outlined below.

Node Test (BSAU125) - This test consists of a 0.25-in.
6,4 mm) thick steel par, its fundamental frequency 100
Includes measurement of attenuation rate in Hz. FIG. 2 is a diagram of the decay rate versus temperature of a par provided with the material of Example 2 (pressure sensitive adhesive). This curve exists around 18 degrees Celsius,
It has a wide peak with a maximum attenuation rate of 16 dB/sec.

Geiger plate test (Geiger Plate T
e5t) - This device is very similar to the Parr test, except that the panel to which the damping sheet is attached is a 20 inch (50, s cm) square plate and the resonant frequency is approximately 160 H2. The test results are shown in Figure 3. The absolute value of the attenuation factor is the second one because the plate structure is different.
Although it is different from the figure, the shape of the performance curve against temperature is extremely similar.

Complex Modulus Test - This test applies the frequency response method of measuring with a specimen clamped at its upper ends. This test is more versatile than the other tests mentioned above because it allows damping factor measurements to be made over a range of frequencies as well as temperatures. This test also uses a thin substrate that can be considered a more typical automotive body panel. Generally, to obtain the data for Representative Example 2, the average diameter dimensions were selected to be 280 rrm x 10 mm x 1 mm gold. This dimension is also determined by the only standard test method available.
That is, it falls within the specifications set forth in ASTM E756-80. In this manner, testing of the pressure-sensitive adhesive material according to Example 2 was carried out using pars made of mild steel.

FIG. 4 is a diagram of composite dynamic loss rate versus temperature. The equivalent attenuation factor is plotted on the vertical axis. Again, a wide peak is observed. This is mainly due to the fact that in the complex modulus test, the thickness of the damping sheet is greater than the thickness of the base holes.

The importance of the thickness ratio can be seen in the equation below, starting from Nono's classical analysis, making appropriate assumptions and ignoring very small terms.

However, η0 = compound dynamic loss rate (damping material + par) η1 =
Dynamic loss rate of the control material M = elastic modulus ratio -E, /E E1 = elastic modulus of the vibration damping material E = elastic modulus of the material T = thickness ratio = 81/) (H1 = vibration damping material thickness The relationship between the thickness composite dynamic loss factor and the damping sheet/par thickness was determined experimentally by testing Example 2 materials of various thicknesses. The results are shown in Figure 5. Also, equation (1)
, and a close agreement was obtained as expected.

The effect of vibration frequency on the composite dynamic loss rate was investigated by carrying out measurements at various resonant frequencies of the par. The measurements were carried out at four temperatures and the results are shown in the diagram of FIG.

It is clear that over standard operating conditions the performance of the material of Example 2 is completely independent of frequency.

For best effect when fixed directly to the panel,
It is necessary that the damping material undergoes the same bending deformation as the panel surface. Therefore, the fixing method dictates the composite limiting performance, since any deformation that takes place in the adhesive layer reduces the strain created in the damping sheet.

The effect of the type of fixing adhesive used with the material of Example 2 was tested using standard Nono equipment. FIG. 7 shows the decay rate as a function of temperature using three adhesive systems. As expected, the best results are obtained with structural adhesives (epoxy resins), while semi-solid contact adhesives and standard pressure sensitive adhesives give similar results.

Therefore, with a view to obtaining the best performance from this material, the adhesive fixation system needs to be as rigid as possible.

However, when considering the practical fixing methods for automotive applications, pressure sensitive adhesives are most appreciated. In the case of the embodiment of Example 2, its inherent performance is so high that high damping rates are obtained even in its pressure-sensitive adhesive state.

The material of Example 2 effectively damps resonant vibrations within the standards for metals used in most automotive body panels, such as doors, roofs, wings, bonnets, and boot lids. On thick nosenels such as floor pans, or in areas where vibration levels are particularly high, a slightly thicker sheet may be required (1 mm thick, weight 2.0 Kg/m2) .

Complete coverage of the panel is unnecessary. Generally, a small pad placed near the center of the non-deformable area is sufficiently effective.

Due to their light weight, the form of sheet material with the greatest potential in the automotive industry is with pressure-sensitive adhesive fixing systems. This eliminates the need for a separate, typically solvent-based adhesive. This allows the component to be easily attached to the back side of a vertical or horizontal surface and produces a permanent bond without any post-curing.

If the body panels are more easily cleaned on the final assembly line, if desired, high temperature pressure sensitive adhesives can be used to attach the parts before the first paint bake.

PVA is a thermoplastic material, so the sheet tends to conform to the contours of the back side when heated when placed on a horizontal surface. In a test using the material of Example 2 and the hot melt adhesive, the samples produced were adapted to deep drawn panels with heating conditions of 5 minutes at 190°C.

[Brief explanation of the drawing]

The figures show the properties of the material according to the invention; Figure 1 shows the elastic modulus and dynamic loss rate in relation to temperature compared to that of unmodified PVA; Figure 2 shows the characteristics of the standard Parr test. Figure 3 is a diagram showing the damping rate by Geiger plate test in relation to temperature. Figure 4 is a diagram showing the complex dynamic loss rate by complex modulus test in relation to temperature. The diagram shown in
FIG. 5 is a diagram showing the composite dynamic loss rate in relation to the material thickness/steel plate thickness ratio; FIG. 6 is a diagram showing the composite dynamic loss rate at various temperatures in relation to the vibration frequency;
and FIG. 7 is a diagram showing the damping rate as a function of temperature for various 7-tone fixing methods. 7jIS in the drawing (no change in 6) Temperature (C) Ftc, 2°Fta, J. Temperature (C) RG, 4゜Thickness ratio (Material of Example 2 ÷ Steel/ξNel) Fta, 5゜Frequency (Hz) Temperature (℃) /47G, 7 Procedural amendment (method) % formula % 2. Invention Name: Method of manufacturing a molded polymer material for vibration damping and sound insulation 3/Relationship with the case of the person making the amendment Name of patent applicant Title: W.V. Strays, LLC 4, Agent 6, Subject of amendment

Claims (1)

[Claims] 1. A vibration damping and sound insulating product comprising mixing a vinyl acetate polymer material with a filler and a plasticizer, and then subjecting this mixture to thermoplastic processing to produce a molded article. A method for producing a molded article of a polymeric material. 2. The method for producing a molded article of a polymeric material for vibration damping and sound insulation according to claim 1, wherein the thermoplasticization process is a rolling process, and therefore the molded article is in the form of a sheet. 3. The method for producing a molded polymer material for vibration damping and sound insulation according to claim 1 or 2, wherein the vinyl acetate polymer material has a molecular weight of K60 to K80. 4. Furthermore, the extender resin and the vinyl acetate polymer material are mixed into 1:
A method for producing a molded polymeric material for vibration damping and sound insulation according to any one of claims 1 to 3, comprising the step of mixing at a weight ratio of up to 5:5. 5. The control according to any one of claims 1 to 4, wherein the plasticizer is a highly solvating plasticizer constituting 4% to 9% of the total composition weight. A method for manufacturing a molded polymer material for vibration and sound insulation. 6. Claims 1 to 5, characterized in that the filler is a mixture of clay and mica ore, and the filler content is 50% to 80% of the total composition weight. A method for producing a molded polymer material for vibration damping and sound insulation according to any one of the above. 7. A method comprising mixing a vinyl acetate polymer material, a filler, and a plasticizer, and then subjecting this mixture to thermoplastic processing to produce a molded article, in which the mixing step is: (a) The following: Ingredients: 24% by weight of polyvinyl acetate as the vinyl acetate polymeric material; 6% by weight of butylbenzyl phthalate as the plasticizer; 1% by weight of a lubricant; 53% by weight of slate powder as part of the filler; and blending 16% by weight of mica as the remainder of the filler until well dispersed; (b) transferring the blended mixture to a mixer and heating it to a temperature of 170°C to 180°C; and ( C) A method for producing a molded polymer material for vibration damping and sound insulation, which comprises rolling the heated mixture at a roller temperature of 60°C to 120°C.