JPH0582862B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a synthetic resin composition containing powdered lead having properties such as soundproofing, vibration damping, shielding from X-rays and radiation, prevention of adhesion of marine organisms, and corrosion protection. [Prior Art] Conventionally, lead and lead compounds in the form of powder or filament are blended into thermoplastic synthetic resin or thermosetting synthetic resin (hereinafter simply referred to as synthetic resin), for example, according to JIS Z 4801.
"Lead-containing rubber sheet and lead-containing vinyl chloride sheet for X-ray shielding" JP-A-60-127254 and JP-A-60-
No. 127341 “Soft-combustible sound insulation material” Utility Model Application No. 1983-109921 “Thermoplastic synthetic resin molded product of metal flake composite”
It is well known that it is used for X-ray protection sheets, sound insulation materials, vibration damping materials, etc., as described in . Therefore, lead powder mixed for these purposes is usually produced using the atomization method (spray method), stamp mill method,
Alternatively, those manufactured by a ball mill method are used. The surface of lead powder produced by such a conventional method is oxidized during the production process or during storage, resulting in a dark gray or black-gray color. Therefore, there is a limit to the amount of lead powder blended with synthetic resin, which has an oxide film on its surface.
If the amount of lead powder is more than %, the dough will become hard.
Uniform dispersion could not be obtained. Therefore, conventional synthetic resin compositions containing lead have naturally had limited effectiveness in achieving the above-mentioned purposes. [Problems to be solved by the invention] The present invention advantageously solves the above problems,
It improves the effect of its original purpose several times,
It has also enabled new fields of effective use.
In other words, by blending lead powder with an active metal surface with almost no oxide film on its surface into a synthetic resin and arranging it in multiple layers, it has properties that are significantly different from those of conventional lead-blended synthetic resins. This is a synthetic resin composition having the following. [Means for Solving the Problems] The gist of the present invention is to add powdered lead, which has almost no oxide film on its surface, to a thermoplastic synthetic resin or a thermosetting synthetic resin at a volume fraction of 15 to 65.
%, and the synthetic resin composition is characterized in that the powdered lead is arranged in almost a layered manner. The powdered lead used in the present invention has a thickness of approximately 0.06~
More than 80% of the particles are 1.0 mm in size and between 4 and 325 meshes, and the apparent density is approximately 2.5 on average.
Refers to scaly lead of gr/cm ³ or less. The powdered lead laminated in the synthetic resin in the present invention is a powdered foil having a silvery white active metal surface with almost no oxide film (approximately 0.1% or less) on its surface. As the lead foil, for example, scaly powder lead obtained by Japanese Patent Application No. 153749/1984 (JP Patent Application No. 13504/1983) entitled "Method for Producing Powdered Lead Scale" is used. When lead of uniform weight is crushed along the sliding surface of its face-centered cubic crystal structure to produce foil, for example, metallic soaps are used as a crushing aid and antioxidant (hereinafter referred to as an auxiliary crushing agent). However, a lead foil whose surface is coated with this auxiliary crushing material at the same time as the active silvery white crushed surface is formed is particularly used. In the present invention, the auxiliary crushing agents used in producing powdered lead include "synthetic resin monomers, synthetic resin solutions,
In addition, it is selected from those suitable as compounding agents for synthetic resins, such as plasticizers for synthetic resins, stabilizers such as lead-based composite stabilizers, or compounds for synthetic resins having a melting point below the processing temperature of synthetic resins. Use lubricant etc. ”. In more detail, these organic compound auxiliaries include hydrocarbon-based liquid paraffin, natural paraffin, micro wax, synthetic paraffin, low molecular weight polyethylene (polyethylene wax), chlorinated hydrocarbons, fluorocarbon, etc. be. Furthermore, fatty acid-based fatty acids include higher fatty acids, oxyfatty acids, and derivatives thereof. In addition, fatty acid amide, alkylene bis fatty acid amide, etc. are examples of fatty acid amide. Furthermore, examples of esters include fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, fatty acid polyglycol esters, and the like.
In addition, examples of alcohols include polyhydric alcohols, polyglycols, polyglycerols, and the like. Also,
Examples of metal soaps include lead stearate, zinc stearate, aluminum stearate, calcium stearate, cadmium stearate, and others, and mixtures of the above may be used as appropriate. These auxiliary crushing agents are in the form of fine powders or liquids, and in particular, in the case of fine powders, those that do not easily aggregate between particles are preferred. It is also effective to select the above-mentioned auxiliary crushing agents alone or in combination of two or more types. When manufacturing lead powder, the above-mentioned auxiliary pulverizing agents are used, and among these, pulverized lead using three of these as auxiliary pulverizing agents: stearic acid, lead stearate, and aluminum stearate, is synthesized. A synthetic resin composition was prepared by adding lead to the resin, and the physical properties, dispersibility, and lamination ratio of lead were measured. Almost the same results were obtained, and no influence of the type of auxiliary crushing agent on the synthetic resin composition was observed. Nakatsuta. Further, the powdered lead foil used in the present invention may be a dark gray or black gray foil having an oxide film on the surface, which is conventionally manufactured by Japanese Patent Publication No. 60-59282 "Method for producing scaly metal powder". The piece was subjected to reduction treatment to remove the oxide film, and if necessary, surface activation treatment was performed, and the lead foil with a silvery white active surface was immediately coated with an antioxidant that satisfied the following conditions. You can also use something. That is, as this antioxidant, a synthetic resin solution, a synthetic resin monomer,
In addition, it is selected from among those suitable as compounding agents for synthetic resins, such as plasticizers for synthetic resins, stabilizers such as lead-based composite stabilizers, or compounds for synthetic resins that have a melting point below the processing temperature of synthetic resins. Lubricants include higher fatty acids, metal soaps, paraffins, polyethylene glycol, low molecular weight polyethylene, and the like. An example of using the synthetic resin solution in the present invention as an antioxidant (auxiliary crushing agent) will be shown. That is, lead of uniform weight is placed in a container, and an epoxy resin adhesive, an epoxy casting resin, or a solution obtained by diluting these to a low concentration solution with an organic solvent, such as a 1 to 3% xylene solution, is crushed. After stirring thoroughly with the above-mentioned lead as an agent, the raw material is put into the hopper of the pressure rolling machine shown in the above-mentioned Japanese Patent Application No. 153745/1983, and pulverized, and the resulting powdered lead + solution is immediately heated. It was dried and the organic solvent was evaporated to obtain powdered lead whose surface was coated with epoxy resin. The thermoplastic synthetic resins of the present invention include polyolefin synthetic resins, such as polyethylene resins and polypropylene resins, ethylene-vinyl acetate copolymer resins, saturated polyester synthetic resins, vinyl synthetic resins and copolymer resins, and fluorine-based synthetic resins. , silicone-based synthetic resins, acrylic acid-based synthetic resins, methacrylic acid-based resins, polyamide-based resins, urethane-based resins, cellulose-based resins, acetal resins, polyimide resins, and polybutadiene-based resins. Further, the thermosetting synthetic resins of the present invention include epoxy resins, phenol resins, melamine resins, unsaturated polyester resins, urea resins, alkyd resins, silicone resins, and furan resins. Plasticizers, stabilizers, fillers, lubricants, antioxidants, etc. may be blended into the synthetic resin as appropriate and necessary. Furthermore, the term "laminated" as used in the present invention refers to the fact that as a result of uniformly dispersing lead powder into a synthetic resin, a large number of lead powder foils are arranged in a certain direction inside the resin in a substantially layered manner. In this case, the lamination is such that when the synthetic resin and the powdered lead are mixed, the powdered lead is arranged in a large number of substantially parallel layers during repeated passes between kneading rolls. In addition, the lamination rate can be improved by a mixing operation using a Banbury mixer, an extruder, a kneader, a Henschel mixer, etc., and especially a rolling operation using a calender or the like. In addition to these, extrusion work using an extruder, molding work using an injection molding machine,
Alternatively, the layers can be effectively laminated by a shaking operation using a vibration molding machine, an arrangement using polarity in an electromagnetic field, and these methods are selected as appropriate. To explain this lamination arrangement, the lamination ratio is shown in the examples of the present invention, which means that in the cross section of the synthetic resin composition containing powdered lead, the powdered lead is in a certain direction or within about 30 degrees from that direction. This refers to the ratio of multiple laminated layers arranged in layers at different angles, measured using a stereomicroscope, and expressed as a percentage. In the present invention, mostly lamination means, for example, the second
As shown in the figure, as a result of visual observation using a stereomicroscope at a magnification of 25 times, the arrangement of powdered lead is approximately 70% or more. Therefore, in the present invention, when powdered lead coated with a film that is an antioxidant film as described above and a film that is also a compounding agent for synthetic resin is blended into a synthetic resin, those films diffuse into the synthetic resin. However, it exhibits the behavior of an original compound, and at the same time, the active lead powder surface comes into contact with the synthetic resin component, preventing the generation of interfacial voids and exhibiting a unique binding force. To explain the relationship between the synthetic resin and the powdered lead when the powdered lead of the present invention is added to the synthetic resin, this powdered lead is extremely easy to disperse into the synthetic resin, and the powdered lead is different from the synthetic resin. Lead can be easily added up to a volume fraction of approximately 65%, and in terms of physical properties, tensile stress, tensile strength, and hardness maintain the performance required for practical use. An even more significant feature is that the powdered lead foil has no oxide film on its surface and has a scaly shape, so it forms an extremely good multi-layered arrangement. If lead powder with an oxide film on the surface formed by conventional methods or lead oxides such as lead circles (Pb ₃ O ₄ ) and litharge (PbO) are present in the synthetic resin, the polarity will be different from that of the powdered lead of the present invention. This increases the binding force of the synthetic resin molecules. Therefore, lead powder or lead oxide obtained by conventional methods maintains the physical properties of synthetic resin, and multiple filling is almost impossible. However, since the powder foil lead of the present invention has almost no oxide film on its surface, its polarity is small and there is no binding force of the synthetic resin polymer due to polarity, and as mentioned above, the particle size is approximately 4 to 325 mesh, which accounts for more than 80% of the particles. It is extremely easy to add powdered lead to a synthetic resin polymer while preserving a fresh metal surface with almost no oxide film, and it retains the original substance of the synthetic resin, and also reduces the volume fraction of lead powder to the synthetic resin. It has now become possible to achieve multiple blending in which up to approximately 65% of the amount is added. Then,
Powdered lead added to synthetic resin has almost no oxide film on its surface, and exhibits good and unique bonding properties with synthetic resin. That is, as described above, the present invention effectively fills a synthetic resin with powdered lead powder, which has almost no oxide film on its surface, in multiple layers. It exhibits good unique binding properties between the two, and based on the synergistic effect thereof, exhibits effective properties for achieving the object of the present invention. Next, in the present invention, the amount of powdered lead added to the synthetic resin is limited to approximately 15 to 65% in volume fraction.
The reason for this is as shown in Tables 3 and 4 of Examples, the sound insulation test and X
The results of the line shielding test show that the effect is not significant at a volume fraction of 15% or less. In addition, it is possible to add it to synthetic resins at a volume fraction of 65% or more, but the dough after kneading is too hard and the elongation is extremely reduced, making it difficult to perform molding processes such as calendaring, and it is difficult to use as a product. The upper limit is set at 65% as it reduces practicality. When the volume fraction is 15% or more, the multi-layered powdered lead is uniformly dispersed in the thermoplastic synthetic resin compound, has a large scaly shape, and has a spread surface, making it difficult for X-rays and radiation. The effect of shielding against noise and noise is significantly increased. The lamination rate of powdered lead in the synthetic resin composition of the present invention is approximately 70% after kneading with a kneading roll, and after kneading and further processing operations such as calendering, it increases to approximately 90% or more, and the conductivity suddenly decreases. Rise. The amount of lead powder added is appropriately selected within the range of volume fraction 15% to volume fraction 65%, taking into consideration the purpose of use and characteristics. The powdered lead foil of the present invention can be easily kneaded by the kneading method and addition order commonly used in this technical field, has uniform dispersion, and has a dense and ideal multilayer arrangement ( (See Figure 2). This ideal and precise multi-layered arrangement has remarkable effects in sound insulation, vibration damping, X-ray and radiation shielding, etc. compared to conventional lead powder, which is present almost as dots in synthetic resin. Compared to conventional synthetic resin formulations containing powdered lead with an oxide film on the surface and having a volume fraction of 43%, for example, the synthetic resin composition of the present invention, in which powdered lead is added at a volume fraction of 43%, has a thickness of 43%. Synthetic resin compositions exhibit the same effects as described above even with half the thickness, and at the same time, they are far superior when compared to the physical properties of synthetic resins, making it easier to achieve objectives that were previously impossible. On the other hand, it is also possible to achieve significant weight reduction. A notable effect of the invention is also the sound insulation effect of this formulation, especially at low frequencies. That is, conventionally used lead plates and lead foils, or laminates using them, have poor restorability and are difficult to maintain smoothness. In comparison, the synthetic resin composition of the present invention is easy to process even when pasting a sheet even at a high filling rate, and has excellent workability, so its practical effects are extremely large. Furthermore, in sound insulation tests, it is natural that the greater the amount of lead powder added, the better the sound insulation effect, as the number of laminated layers increases and the density of lead in the synthetic resin increases. Moreover, when comparing the sound insulation test (Table 3) of the 2 mm lead plate (see Comparative Example 8) and the present invention examples 1 to 4 of the present invention, it was found that the sheet of synthetic resin composition of 1 mm was The difference from the dB value is large, and in particular, sheets containing powdered lead at a volume fraction of 43% or more show performance almost close to that of a 2 mm lead plate. It was found that the effect is particularly remarkable at low frequencies below 110Hz. In addition, when comparing a 1 mm thick sheet of a synthetic resin composition containing powdered lead at a volume fraction of 43% in the conventional method, the difference between the sheet containing powdered lead of the present invention and the sheet containing powdered lead of the present invention is small, but the low frequency The sound insulation effect is excellent. In addition, the former has a volume fraction as in the present invention.
Since it is almost impossible to fill a large amount of 50% or more, the synthetic resin composition of the present invention, which can be blended in a large amount, opens up a field of new effects that could not be realized in the past. In other words, it has almost the same effect as a lead plate of the same thickness in terms of sound insulation, X-ray and radiation shielding, vibration damping, etc., and is smoother and lighter in terms of ease of handling, workability, and workability. It has several superior beneficial effects based on the synergistic effect with the base synthetic resin. [Example] The present invention will be specifically explained below with reference to Examples. The evaluation methods of the sound insulation test and the X-ray test in Examples are as follows. Evaluation method of sound insulation test Test equipment: (1) A sound insulation sheet is pasted on the circumference and bottom of the wooden box.
Sound insulation test equipment with the top open. A sound source that generates various frequencies was housed inside. (2) Sound level meter NA-09 model manufactured by Rion Co., Ltd. Test conditions: (1) Temperature: 25°C (2) Location: Closed room (3) For hard materials such as lead plates, an iron frame was used as a presser. Test method: Place the sample on top of a sound insulation test device with a sound source inside, make the device completely sealed, and measure the decibel value (dB) with A-weighting by placing a sound level meter at a distance of 70 cm from the top of the device. did. Evaluation method of X-ray test Test device: X-ray diffraction device JDX-7E model manufactured by JEOL Ltd. Test method: The X-rays were adjusted to travel straight, and the sample was inserted between the radiation source and the Geiger counter. The count number (c/sec) of a Geiger counter was measured by emitting X-rays. Test conditions: (1) Temperature: 25°C (2) Angle: 0 Example 1 Tables 1-1 and 1-2 show the results of powdered lead on thermoplastic synthetic resin compositions based on vinyl chloride resin. Examples and comparative examples showing the amount of compounded are shown below. In each case, a 6-inch mixing roll was used for kneading, and each product was molded to a thickness of 1 mm using a calender. The physical properties, lamination rate, and dispersibility of the obtained compound sheet were measured.

【table】

【table】

【table】

【table】

[Table] Invention Example No. 1 shown in Tables 1-1 and 1-2
The measured values shown in Table 3 were obtained using the sheets of Comparative Examples Nos. 1 to 4 and Comparative Examples Nos. 1 to 9.

[Table] From the above data, the synthetic resin composition of the present invention is 2
Even a 1 mm sheet has a considerable effect compared to a mm lead plate. When handled as a sheet, lead plates have poor workability, and unless an iron frame is used, there is a gap between the lead plate and the equipment, making it ineffective. In contrast, the sheet made of the synthetic resin composition of the present invention was extremely soft and flexible and easy to handle. Furthermore, it is found that the effect at low frequencies is particularly excellent, and has an effect equivalent to that of a lead plate, and is significantly more effective than a general commercially available urethane sound absorbing material. Figure 1 shows the equipment used in this test. In the figure, 1 is a sound source, 2 is a sound insulation measurement box, 3 is a lead plate lined with a lining, 4 is a sample sheet, and 5 is a sound level meter. Fig. 2 shows a stereoscopic microscope photo of a cross section of the synthetic resin composition sheet (Example 2 of the present invention) used in the sound insulation test.
Further, the same photograph of Comparative Example 5 is shown in FIG. Invention Example No. 1 shown in Tables 1-1 and 1-2
Using the sheets of Comparative Examples Nos. 1 to 5 and Comparative Examples Nos. 1 to 8, the thicknesses were adjusted to 0.25 mm and 0.1 mm, respectively, and the measured values showing the X-ray blocking effect shown in Table 4 were obtained.

[Table] As a result of the X-ray shielding test, it was found that when 500 parts or more of powdered lead was added, it had a considerable shielding effect, and when 1,500 parts or more was added, the shielding effect was close to that of a lead plate. Example 2 Table 5 shows examples of the present invention and comparative examples showing the blending amount of powdered lead in thermosetting synthetic resin compositions containing epoxy resin as the main material. In either case, the resin curing agent is placed in a container equipped with a stirrer, the powdered lead is mixed in while stirring, and after thorough mixing, the composition is cast into a mold and heat-pressed.
The mixture was heated under pressure at a temperature of 140°C for 5 minutes and formed into a sheet. In the case of adding 1500 parts by weight or more of powdered lead, the epoxy resin was diluted with a solvent, and after mixing, the solvent was evaporated and sheet-formed under the same conditions as above. Table 6 shows the measurement of physical properties, lamination ratio, and dispersibility.

【table】

【table】

[Table] Invention examples No. 5 to 8 and comparative example No. 10 shown in Table 5
-13 sheets were used to obtain the measurements in Table 7.

[Table] Comparing the above data with the measured data of the vinyl chloride resin composition (Table 3), almost the same measured values were obtained. Similar to vinyl chloride resin compositions, it is extremely effective at low frequencies. Invention examples No. 5 to 8 and comparative example No. 10 shown in Table 5
~13 sheets were used, the thickness was adjusted to 1 mm, and the 8th
Measured values showing the X-ray blocking effect shown in the table were obtained.

〔Effect of the invention〕

As mentioned above, the synthetic resin composition of the present invention has the effect of arranging a large amount and uniformly multiple layers of powdered lead having an active metal surface and producing good binding force between the polymer molecules and the powdered lead. Due to the synergistic effect of these, it exhibits extremely remarkable effects in sound insulation, vibration damping, X-ray shielding, radiation shielding, prevention of marine organisms adhesion, corrosion prevention, etc. that cannot be achieved with conventional products.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the sound insulation test equipment used in the examples, and Fig. 2 is the powdered lead obtained by the present invention.
Stereomicrograph diagram showing the cross-sectional structure of the vinyl chloride resin composition (Example 2 of the present invention) containing 1500 parts by weight (×
25), Figure 3 is a stereoscopic micrograph (x25) showing the cross-sectional structure of a vinyl chloride resin composition (Comparative Example 5) containing 1500 parts by weight of conventional commercially available lead powder (atomized, passed through 200 meshes). It is. 1... Sound source, 2... Sound insulation measurement box, 3... Lead plate lined, 4... Sample sheet, 5... Sound level meter.

Claims (1)

[Claims] 1. Thermoplastic synthetic resin or thermosetting synthetic resin contains 15 to 65% by volume of powdered lead with almost no oxide film, and most of the powdered lead is arranged in layers. A synthetic resin composition containing powdered lead.