JPS6187741A - Low-temperature-moldable sound-insulating composition - Google Patents

Abstract

PURPOSE:A low-temperature-moldable sound-insulating composition which can readily form a molding merely by pressing at room temperature, obtained by mixing a high-density polyethylene of a specific gravity in a specified range with a plasticizer, a metal (oxide) powder or an inorganic powder. CONSTITUTION:100pts.wt. high-density polyethylene of a specific gravity of 0.991-0.975 is mixed with 5-80pts.wt. plasticizer (e.g., dioctyl phthalate or aromatic rubber softener) and 60-700pts.wt. at least one additive selected from among metal powders, metal oxide powders and inorganic powders (e.g., aluminum powder, titanium oxide powder or calcium carbonate) to obtain the purpose low-temperature-moldable sound-insulating composition of a density of 1.3-3.2g/cm<3>. This composition can be suitably used for molding a sound- insulating material for industrial machines having an irregular, curved or like surface for attaching a sound-insulating material, for example, a sound-insulating material for cars.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sound insulating composition that can be formed into secondary molding at normal room temperature (5°C to 40°C) without requiring special heating. More specifically, a low-temperature formable sound insulation composition suitable for shaping sound insulation materials installed in industrial equipment such as automobiles, electrical equipment, etc., in which the mounting surface of the sound insulation material has various shapes such as uneven or curved surfaces. It's about providing things.

BACKGROUND OF THE INVENTION In recent years, various types of industrial equipment have been fitted with sound insulating materials, especially around their power parts, to prevent noise.

In the case of automobiles, sound insulating material is installed on the entire surface of the interface between the engine side and the interior of the vehicle to prevent engine noise.

These sound insulating materials are sometimes installed in the form of a sheet, but in general, the place where they are installed is rarely flat, but has an uneven or curved surface. A method is used in which the shaped article is previously shaped into the shape of , and then the shaped article is fitted onto the mounting surface.

Conventionally, as a sound composition for forming the above-mentioned sound insulating material, one of polyvinyl chloride, styrene butadiene rubber, polyethylene vinyl acetate, atactic polypropylene, or a mixture thereof is used as a base material. It is known that the density is increased by adding metal oxide powder and/or inorganic powder, and if necessary, a plasticizer is added.

Next, as a method for forming an excipient from the sound insulating composition, the composition is mixed in a super mixer to make a dung pound, and the dung pound is put into an extrusion molding machine or a calender molding machine to form an excipient into an appropriate shape. Form a thick sheet,
Next, the sheet is held between molds, heated and pressed in a range of 120°C to 120°C using a press molding machine, and left to cool in the atmosphere for a certain period of time to form a shaped object. Ta.

In this way, in order to form a shaped product from a conventional sound insulation composition, it is necessary to heat and press it with a press molding machine, so a heat source and heating device are required for shaping, and furthermore, Since it takes a considerable amount of cooling time to complete the process, there are disadvantages in that the productivity is low and the formed excipients are extremely expensive.

Therefore, in order to eliminate the low productivity and high cost caused by conventional shaping methods, it is conceivable to form a shaped product by simply pressing it at room temperature without heating it with a press molding machine. In the case of conventional sound insulation compositions, for example, the above-mentioned compositions using styrene-butadiene rubber as a base material, a shape is temporarily formed, but over time it restores itself to the original sheet shape, and polyethylene In the case of a composition having vinyl acetate or atactic polypropylene as a base material, the sheet was damaged by the pressing force of the press molding machine, and no excipient was obtained.

Problem to be Solved by B Therefore, the present invention eliminates the need for heating and cooling to form excipients, unlike conventional sound insulating compositions, and allows excipients to be easily formed by simply pressing at room temperature. An object of the present invention is to develop and provide a low-temperature moldable sound insulation composition.

Fiot! lL In view of the drawbacks of Somerai's sound insulation compositions as described above, the present inventors conducted extensive research and found that high-density polyethylene having a specific gravity in the range of α941 to α975 was used instead of the base material constituting the conventional composition. It was discovered that a sound insulating composition with excellent low-temperature formability can be obtained by using this as a base material, leading to the present invention.

The low temperature moldable sound insulation composition of the present invention has a specific gravity Q of 941 to Q
, 100 parts by weight of high-density polyethylene in the range of 975, 5 to 80 parts by weight of plasticizer, and one or more additives selected from the group consisting of metal powder, metal oxide powder, and inorganic powder. Consisting of 60 to 700 parts by weight, density 1.6 to
It is characterized by being in the range of 3.2%/cIn.

High-density polyethylene with a specific gravity in the range of 0.941 to α975 is used as the base material of the present invention, and metal powders include powders of lead, zinc, iron, copper, aluminum, etc., and metal oxide powders. For example, toughened lead, zinc oxide, iron oxide, titanium oxide, and magnesium oxide powders can be used, and as inorganic powders, powders such as calcium carbonate, barium sulfate, and aluminum hydroxide can be used, but in the present invention, these metal powders, 1 selected from the group consisting of metal oxide powder and inorganic powder
One species or two or more species can be arbitrarily selected and used as an additive.

In addition, the plasticizers used in the present invention include phthalate esters containing DOP, which are generally used for plastics;
Polyester-based, phosphoric ester-based, fatty acid ester-based, and halogenated paraffinic plasticizers, as well as paraffinic, naphthenic, aromatic, and subclass plasticizers commonly used as rubber softeners, can also be used. It is preferable to use a phthalate ester plasticizer or an aromatic softener.

Next, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Examples 1-3 and Comparative Examples 1-2 In Table 1 below, Examples 1-3 show the low temperature moldable sound insulation composition of the present invention, and Comparative Examples 1-2 show the implementation of the conventional sound insulation composition. Give an example. In the physical properties column, the composition materials shown in the formulation column of Table 1 are mixed in a Super Miki F- (1100 RPM) to make a dung pound, and then the dung pound is put into an extruder to form a 1-inch thick sheet. mold, 24
The results of measuring the physical properties of the sheet after being left in the atmosphere for a period of time are shown below. The above sheet was made using a 65u5i5 extruder, the die was 500111jl, the thickness of the sheet was adjusted to 1U using a 1-width T-type die, and the cylinder temperature was 1U.
400~170°C 1 die temperature 150°~160°C
It was molded under extrusion conditions.

In addition, since the composition of the present invention contains a large amount of metal powder, metal oxide powder, etc. as a filler for the purpose of improving sound insulation, the molding machine used to form the sheet may be restricted depending on the ratio of the amount added. Ru. In other words, if the amount added is 200 parts by weight or less with respect to 100 parts by weight of the base material, both an extrusion molding machine and a calendar molding machine can be used, but if 200 parts by weight or more is added, molding with an extrusion molding machine is possible. do.

*1: Santic F180 manufactured by Asahi Kasei Corporation Specific gravity (l1954*2
: Santic J240 manufactured by Asahi Kasei Kogyo ■ Specific gravity α969*6: NUC-8122 manufactured by Nippon Unicar ■ Specific gravity 0.924 *4: 5G-iioo manufactured by Nippon Carbide Industries ■ Specific gravity 1.4 *5: Measured by the underwater substitution method.

*6: Measured according to JISK6732.

*7: Performed based on the permanent elongation test of JIS K6301, the tension is immediately released after 50% stretching, and the elongation percentage remaining after 24 hours is considered the residual elongation.

Next, a sheet material with a thickness of 1 u having the composition and physical properties shown in Table 1 was placed at a room temperature of 24°C, with a minimum of 1
A male mold with a protrusion of 5u1 maximum of 801u1 is sandwiched between a female mold with a concave portion corresponding to the male mold, and a surface pressure of 150 k is applied using a press molding machine not equipped with a heating device.
In Table 2, 24 hours have elapsed since the pressure was released after 5 seconds, and "good" refers to a state in which the mold is well reproduced. This refers to a state in which a number of breaks have occurred in the sheet due to pressure, and "unsatisfactory" refers to a state in which a sheet that has been once shaped by pressure recovers over time and returns to its original sheet shape before forming.

As shown in Tables 1 and 2 above, the compositions of the present invention shown in Examples 1 to 6 form excipients that faithfully reproduce the mold, but the compositions of Comparative Example 1 Sound insulating materials made of compositions with density polyethylene as a base material have extremely low tensile strength and elongation rate, and the elongation of the sheet cannot cope with the pressure applied by the molding die, resulting in breakage and making it impossible to put it into practical use. Ta. In addition, the sound insulation material made of the composition having vinyl chloride as a base material in Comparative Example 2 was
Although it was once shaped along the mold, it gradually recovered after the pressure was released, and about 15 minutes later it returned to its original flat sheet shape, failing to reach the desired target. .

Effects of the Invention As detailed in the above Examples, the low-temperature moldable sound insulation composition of the present invention is formed into a sheet using an extrusion molding machine or a calendar molding machine, and then pressed using a press molding machine at normal room temperature. Since it has the characteristic that a molded object that reproduces a mold can be easily formed by simply using a mold, it requires less heat source and heating equipment to form the molded object than a sound insulation material made from a conventional sound insulation composition. Since this is not necessary and the cooling time is also significantly shortened, productivity is greatly improved and costs are reduced, which has great economic effects.

Claims (1)

[Claims] 100 parts of high-density polyethylene with a specific gravity in the range of 0.941 to 0.975, 5 to 80 parts by weight of plasticizer, metal powder,
Contains 60 to 700 parts by weight of one or more additives selected from the group consisting of metal oxide powder and inorganic powder, and has a density in the range of 1.3 to 3.2 g/cm^3 A low-temperature moldable sound insulation composition characterized by: