KR20040105150A - Composition of expandable filler for filling vacant space in vehicles - Google Patents

Abstract

PURPOSE: Provided is a foaming filler composition for filling inside of voids in cars, which inhibits noises and vibrational sounds from being transferred into cars through the voids, and has improved heat resistance and anti-aging property. CONSTITUTION: The foaming filler composition for filling inside of voids in cars comprises: 25-35 wt% of EPDM(ethylene propylene diene monomer) rubber, 1-10 wt% of a thermoplastic rubber, 1-5 wt% of zinc oxide(ZnO), 1-5 wt% of stearic acid, 1-4 wt% of carbon black, 20-40 wt% of calcium carbonate, 18-30 wt% of clay, 5-25 wt% of a processing oil, 2-6 wt% of sulfur, 1-10 wt% of 2-mercaptobenzothiazolate disulfide, 4-10 wt% of azodicarbonamide and 1-6 wt% of urea. The thermoplastic rubber may be selected from the group consisting of styrene-butadiene copolymer and styrene-isoprene copolymer.

Description

Composition of expandable filler for automobile voids Filling vacant space in vehicles}

The present invention relates to a foaming filler composition for automobile interior pores, and more specifically, to use a mixture of EPDM (Ethylene Propylene Diene Monomer) rubber and thermoplastic rubber as raw material rubber, calcium carbonate as a functional filler, flow during foaming To prevent the clay, processing oils to give flexibility when mixing, zinc oxide, stearic acid, colorant as a color enhancer for imparting heat resistance and improving aging resistance, carbon black, azodicarbonamide for forming foam bubbles, urea, foams formed permanently Sulfur, 2-mercaptobenzothiazolate disulfide for fixing with a suitable ratio is mixed to prepare a foaming filler composition, which is mounted inside the car structure voids and foamed by heating to fill the inside of the structure voids while driving the car Sound and vibration transmitted inside to vehicle interior The present invention relates to a foam filler composition for automobile void internal filling for controlling sound.

In case of the product for filling inside the space of existing automobile structure, it is directly attached to the inside surface of structure structure by the adhesive force of the adhesive layer on one side of the product through manual labor of the worker. Could occur. In addition, due to this, the filling is not completely completed when passing through the electrodeposition paint drying oven, and the unfilled phenomenon frequently occurs. When applying the inner surface of the panel, certain spaces and areas are required. As a result of receiving a lot of cases, there are many cases that cannot be applied smoothly to the area that needs to be charged, thus affecting the quality of the automobile.

Therefore, the present inventors use a mixture of EPDM rubber and thermoplastic rubber as a raw material rubber to solve the above problems, 2-mercaptobenzothiazolate disulfide as a vulcanizing aid, and azodicarbonamide as a blowing agent By using urea and mixing other processing aids, coloring reinforcing agents, flow inhibitors, fillers, processing oils and vulcanizing agents in an appropriate ratio to prepare foam filler compositions, it has been found that it has excellent filling performance with high foaming rate and low thermal fluidity. The present invention has been completed.

Accordingly, the present invention provides a foam filler composition for filling the interior of the automobile cavity filling the interior of the structure voids by heating and controlling the noise and vibration sound transmitted to the interior of the vehicle through the interior of the structure voids when driving the vehicle. The purpose is to provide.

The present invention is EPDM (Ethylene Propylene Diene Monomer; ENB type) 25-35% by weight, thermoplastic rubber 1-10% by weight, zinc oxide (ZnO) 1-5% by weight, stearic acid 1-5% by weight, carbon black 1 to 4% by weight, 20 to 40% by weight of calcium carbonate, 18 to 30% by weight of clay, 5 to 25% by weight of processed oil, 2 to 6% by weight of sulfur, 1 to 10% by weight of 2-mercaptobenzothiazolate disulfide, It is characterized by a foaming filler composition for automobile void internal filling comprising 4 to 10% by weight of azodicarbonamide and 1 to 6% by weight of urea.

Referring to the present invention in more detail as follows.

The present invention relates to a material that is applied to the interior of the pores of automobile structures (pillar, sealside, wheelhouse, dashpannel, etc.), the composition for internal filling of the present invention is formulated After mixing a large amount of raw materials in the equipment, it is possible to extrude, fabricate a sheet (Sheet) fabric using a extruder, and then process into a uniform shape by using a press (Press) equipment.

Hereinafter, the components constituting the composition of the present invention will be described in detail.

EPDM (Ethylene Propylene Diene Monomer; ENB type) rubber used as a raw material rubber in the composition of the present invention is excellent in ozone resistance, weather resistance, heat aging resistance, and cold resistance, and is generally used as a material for automobile parts. In 25 to 35 weight% is used in the whole composition. If the content of EPDM is less than 25% by weight, it may not form a complete closed cell, and if it exceeds 35% by weight, foam formation may be suppressed to obtain a desired foaming rate.

In addition, the present invention is characterized by using 1 to 10% by weight of the thermoplastic rubber (Thermoplastic rubber) with the EPDM as a raw material rubber in the total composition, the thermoplastic rubber is excellent compatibility with the EPDM, foam It gives the effect of improving the tensile strength and elongation necessary for formation. In particular, since the thermoplastic rubber contributes to the formation of a stable close cell after expansion due to decomposition of the foaming agent, a foam having excellent physical properties that are differentiated from the composition using the conventional EPDM rubber alone. This is possible. As the thermoplastic rubber, styrene-butadiene copolymer and styrene-isoprene copolymer may be used. If the content is less than 1% by weight, the tensile strength and elongation may not be improved. If the tensile strength exceeds 10% by weight, the tensile strength is increased, but the elongation is reversed and the foaming rate is decreased.

In the present invention, zinc oxide (ZnO) and stearic acid are used in the composition as a processing aid, respectively, in an amount of 1 to 5% by weight. The zinc oxide promotes the reaction of the vulcanizing agent, the vulcanizing aid, the foaming agent, the foaming aid, and the like, when the content is less than 1% by weight, it does not exhibit a reaction promoting effect, and when it exceeds 5% by weight, the reaction promoting effect is no longer improved. It is not economical. In addition, the stearic acid improves the compatibility of the composition of the present invention, if the content is less than 1% by weight, there is a problem in compatibility when mixing, if it exceeds 5% by weight is not mixed stably inside the mixture and leaching to the product surface There is a problem.

Carbon black used as a color enhancer in the present invention improves the anti-pollution resistance and aging resistance of the product, and is used in the total composition 1 to 4% by weight, if the content is less than 1% by weight, 4 weight is not displayed, If it exceeds%, there is a problem of roughening the product surface because it is not evenly dispersed in the mixture.

The calcium carbonate used as the filler in the present invention prevents deformation of the product and stabilizes dimensions, so 20 to 40% by weight of the total composition is used. If the content is less than 20% by weight, the moldability of the product is lowered and deformation occurs. And, if it exceeds 40% by weight there is a problem that the hardness of the product increases and the foaming rate is reduced.

In the present invention, the flow preventing effect is excellent to prevent the flow down when forming the foam to form a stable cell, that is, the clay used as a flow inhibitor is used 18 to 30% by weight in the total composition, if the content is less than 18% by weight There is no flow resistance effect on the back, and if it exceeds 30% by weight, the flow resistance is increased but the foaming rate is reduced.

In the present invention, the process oil for lubricating upon mixing the various components of the composition and improving the elongation at the time of foam formation is used in the total composition 5 to 25% by weight, if the content is less than 5% by weight It does not evenly disperse and exceeds 25% by weight increases the fluidity during foam formation to reduce the filling effect. It is preferable to use naphthylene-based processing oil as the processing oil.

In the present invention, sulfur, which is a vulcanizing agent for permanently fixing the shape after foam formation by forming a crosslinked structure of the raw material rubber, is used in the total composition of 2 to 6% by weight. If the content is less than 2% by weight, the crosslinked structure is coarse to form a foam. No. If it exceeds 6% by weight, the crosslinked structure becomes dense and there is a problem of suppressing foam formation.

In the present invention, 2-mercaptobenzothiazolate disulfide (MBTS, 2-mercaptobenzothiazolate disulfide) as a vulcanizing aid to improve the vulcanization rate and crosslinking density to prevent the flow during foam formation and to promote the formation of high foams, ~ 10% by weight, if the content is less than 1% by weight, the foaming gas is decomposed before forming the crosslinked structure to form a foam, if the content exceeds 10% by weight the crosslinked structure is formed before decomposition of the foamed gas foam Inhibits formation.

Azodicarbonamide (AC) and urea used as blowing agents in the present invention are used in the total composition of 4 to 10% by weight and 1 to 6% by weight, respectively. The azodicarbonamide has a greater amount of gas at the time of loading than other blowing agents, is not toxic to decomposition gas, and the reaction occurs stably so that it is safe to use in an automobile production process, and if the content is less than 4% by weight, the desired foaming rate is achieved. If it is not obtained, if it exceeds 10% by weight excess foaming gas is generated, there is a problem that a stable foam is not formed. In addition, the urea improves the foaming speed, if the content is less than 1% by weight does not achieve the desired foaming rate, if the content exceeds 6% by weight the foaming gas is decomposed before the cross-linked structure is formed to form a foam There is.

Looking at the method for producing a foam filler composition of the present invention using the above components are as follows.

The above components are mixed in a compounding equipment (kneader, open roll, etc.) and extruded through an extruder to prepare a sheet, and then the foam filler composition is molded using a press facility.

The molded foam filler composition is made of resins (PA; Polyamaid, PC; Polycarbonate, PET, Polyester, etc.) having heat resistance at 120 to 230 ° C., which is a temperature of paint drying in a conventional automobile manufacturing process, through an injection molding machine. It is inserted into the fixing aid, or the foam filler composition is injected into the fixing aid (the foam filler composition supports the foam until the filler fills the air gap inside the structure, and serves to fix the foam on the vehicle panel. Noise that is transferred to the interior of the vehicle through the interior of the structure cavity when the vehicle is driven by foaming by heating and filling the interior of the structure void when passing through the paint drying after a series of self-assembly And vibration sound.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Examples and Comparative Examples

Next, the composition was prepared in the following manner with the ingredients and contents shown in Table 1.

Next, the components shown in Table 1 were blended using a compounding equipment (kneader), and a sheet processed through an extruder was molded in a press to prepare a composition for foam filling.

Ingredient (% by weight) Example Comparative example Raw material rubber EPDM 27 26 TPR ¹ 3 - Processing aid Stearic acid 2 One ZnO 2 5 Peptizer - 6 Color Enhancer Carbon black 2 3 Flow inhibitor Clay 20 21 Filler CaCO ₃ 22 7 Processing oil Processing oil 9 16 Vulcanizer S 3 One Vulcanization p-quinone-dioxime - 0.5 EUR ² - 0.5 TMTM ³ - 2 MBTS 3 - blowing agent OBSH ⁴ - 7 DPT ⁵ - 4 AC 5 - Urea 2 - TPR: styrene-butadiene copolymer 2. EUR: diethyl thiourea 3. TMTM: Tetramethylthiuram monosulfide4. OBSH: p, p-oxybis benzene sulfonyl hydrazide 5. DPT: N, N-dinitroso pentamethylene tetramine

Test Example

In order to confirm that the compositions for foam charging prepared according to the above Examples and Comparative Examples had a filling performance, the test was carried out by the test method shown in Table 2 below, and the results are also shown in Table 2.

Test Items Test Methods Requirements Comparative example Example Specific gravity (g / cm 3) MS 256-33, section 4.2 1.2 ± 0.2 1.2 1.2 Absorption rate (%) MS 256-33, paragraph 4.5 100 or less 30 25 Volume change rate (%) MS 256-33, section 4.6 More than 800 850 1000 stability(%) MS 256-33, paragraph 4.7 720 or more 730 800 Foam magnification ⁴ Standard BAKE ¹ MS 256-33, section 4.8 over 10 10 11 OVER BAKE ² 10 11 UNDER BAKE ³ 10 11 Thermal fluidity (mm) MS 256-33, paragraph 4.9 50 or less 30 20 Corrosion resistance MS 256-33, paragraph 4.11 No rust and corrosion products none none Standard BAKE: 185 ± 2 ° C. X 20 minutes 2. OVER BAKE: 215 ± 2 ℃ X 20 minutes 3. UNDER BAKE: 170 ± 2 ° C. X 20 minutes 4. Foam ratio = thickness of the sheet after curing (mm) / thickness of the sheet before foaming (mm)

As shown in Table 2, it was confirmed that the composition according to the present invention has a higher filling ratio and a higher thermal fluidity than the comparative example of the conventional filling composition having a filling performance.

As described above, the foam filler composition for automobile void internal filling of the present invention is a mixture of EPDM rubber and thermoplastic rubber as a raw material rubber, 2-mercaptobenzothiazolate disulfide as a vulcanizing aid, and azodicarbonamide as a blowing agent. Using urea, it has a high expansion ratio and low thermal fluidity, so it has better filling performance than existing filling products.

Therefore, the foam filler composition of the present invention can be usefully used as a material applied to the interior of the pores of automobile structures (Phillar, Sillside, Wheelhouse, dashpannel, etc.).

Claims (2)

25% to 35% by weight of EPDM rubber, 1 to 10% by weight of thermoplastic rubber, 1 to 5% by weight of zinc oxide (ZnO), 1 to 5% by weight of stearic acid, 1 to 4% by weight of carbon black, 20 to 20% of calcium carbonate 40 wt%, clay 18-30 wt%, processing oil 5-25 wt%, sulfur 2-6 wt%, 2-mercaptobenzothiazolate disulfide 1-10 wt%, azodicarbonamide 4-10 wt% and Foam filler composition for automobile void interior filling, characterized in that containing 1 to 6% by weight of urea. The foam filler composition of claim 1, wherein the thermoplastic rubber is selected from a styrene-butadiene copolymer and a styrene-isoprene copolymer.