KR20020086346A - Foaming composition for protecting noise in body frames of vehicles - Google Patents

Abstract

PURPOSE: Provided is a foaming composition which is used for blocking voids between frames of car body or attached to frame wall, so as to remove an engine noise of car, and a driving noise owing to tire and wind. CONSTITUTION: The composition predominantly comprises 50-60 wt%(based on total weight of the composition) of mixture of 85-95 wt% of ethylene acetic vinyl copolymer(EVA) and 5-15 wt% of any one of low density or high density polyethylene(PE), as main ingredient; 7-10 wt% of 2,2'-azobisisobutyronitrile as blowing agent; 1-2 wt% of t-butylhydroperoxide as a vulcanizing agent; and 3-8 wt% of any one of polyethylene wax or paraffin wax as a softening agent. Also, the composition further comprises stearic acid and zinc oxide as a processing aid; carbon black as a colorant; clay as an antiflow agent; calcium carbonate as a filler; process oil as a softening agent; sulfur as a vulcanizing agent; p-quinonedioxime as an accelerator; and OBSH(oxybisbenzene sulfonyl hydrazide) or DPT(dinitroso pentamethylene tetramine) as a blowing agent.

Description

Foaming composition for protecting noise in body frames of vehicles

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a foam composition for blocking air gaps between a vehicle body frame or adhering to a frame wall to remove vehicle noise caused by engine noise, tires and wind noise of a vehicle. A composition of sound insulation foam of a vehicle body frame fixed to the vehicle body frame together with a support plate to block the frame gap, or directly attached to the vehicle body frame wall without a support plate to be adhered to the vehicle body frame while being foamed by heat during electrodeposition coating. It is about.

The conventional foam composition for noise prevention (sound insulation) of the vehicle body frame is mainly made of EPDM (Ethylene Propolene Diene Monomer) as a processing aid, stearic acid and zinc oxide, as a coloring agent, carbon black, clay as a flow inhibitor, It is made by adding calcium carbonate as a filler, process oil as a processing oil, sulfur as a vulcanizing agent, and P-quinone dioxime as a vulcanizing agent, and OBSH (Oxy Bisbenzenesulfonyl Hydrazide) or DPT (Dinitroso pentamethylene tetramine) as a blowing agent. In order to make the foam of the vehicle body frame sound insulation foam consistently adhere to or adhere to the steel sheet in the vehicle body frame, the tackifier is commonly adhesive at room temperature and then adhesively cured by heat. That is, the adhesive material at room temperature is added to the composition or otherwise prepared It is applied to the surface of the foam to protect it with release paper, and when it is attached (adhesive) to the steel plate (hereinafter referred to as the body steel plate) in the double frame of the body, the release paper is attached and adhered. Such foam is flexible and flexible. This defect is not good and can not stick to every corner of the curved body frame, so that the foam does not adhere to the body frame. Also, if only one foaming agent is used, it is decomposed and foamed at too high a temperature or decomposed and foamed at a too low temperature. In order to remove the closed edges that are too fast or too slow, the foaming aid must be added and various additives such as other additives must be added.

The present invention improves the drawbacks of the above-mentioned body frame sound insulation foam composition to insert or attach to a support plate that blocks the gap between the body frame, or directly attached to the body frame wall with a bolt, foamed by heat during electrodeposition coating And to provide a vehicle frame soundproof foam composition to prevent various noises of the vehicle and to remove resonance by hardening, and to reduce the type of material constituting the composition of the soundproof foam of the car body frame. Inserting or attaching to the support plate to be inserted into and fixed to the space between the body frames or bolting directly to the wall of the body frame without the need to add or apply separately, the foam hardening and adhesion is easily performed by heat during electrodeposition coating of the vehicle. Under the foam even without adding special foaming aid If only a reduced nose provides a composition of the vehicle body frame for a sound insulation foam which is foamed in an easy fit with the heat and time at the time of electrodeposition coating it is for instance described in detail as follows.

1 is an exemplary embodiment of the present invention applied to a support plate for a vehicle body frame with a foam composition according to the present invention.

Explanation of symbols on the main parts of the drawings

1: foam 3: body frame

5: support plate 6: elastic fastening piece

5a, 5b: upper and lower plate 7: groove

A composition of a vehicle body frame sound insulation foam which is interpolated or fixed to a support plate to block the space between the vehicle body frames or bolted to the body frame wall by itself as a support plate, wherein stearic acid, zinc oxide, and colorant are used as processing aids in the main material of the composition. Low carbon black, clay as a flow inhibitor, calcium carbonate as a filler, process oil as a softener for processing, sulfur as a vulcanizing agent and P-quinone dioxime as a vulcanizing agent and OBSH (Oxy Bisbenzene Sulfonyl Hydrazide) as a foaming agent or DPT (Dinitroso Pentamethylene) In the composition of the foam sound insulation foam of a vehicle body made by adding Tetramine),

As a main material, a mixture of 85 to 95 wt% of ethylene vinyl acetate copolymer (EVA) having hot melt adhesiveness with respect to the total composition weight and 5 to 15 wt% of either low density or high density polyethylene (PE) is used as a main material. 50 to 60 wt% with respect to the composition, but instead of the foaming agent OBSH, foaming agent that is capable of foaming according to the temperature and time during heating of the electrodeposition coating without foaming aid in the foaming of the EVA and PE mixture foaming agent (AZDN: Azobisisobutyroni trile) 7 to 10 wt% of the total composition weight, and instead of sulfur and vulcanization accelerator P-quinone dioxime, vulcanizing accelerator and vulcanization accelerator of vulcanization and vulcanization accelerator showing excellent performance only vulcanization accelerator 1 to 2 wt% of the organic peroxide, such as cbenhydroperoxide, is added to the total composition weight, Instead of oil, any one of polyethylene wax and paraffin wax added to EVA and PE with excellent processability, compatibility, and mold release property is added in an amount of 3 to 8 wt% based on the total weight of the composition. Composition.

2,2'- azoisobutyronitrile, which is a foaming agent used in the present invention, is characterized in that the foam made of EVA and PE mixture without foaming aid is most suited to the temperature and time during electrodeposition coating of the vehicle body. Polyethylene wax and paraffin wax, which impart vulcanization (acceleration) and flexibility and processability, are characterized by their function only in the mixture of EVA and PE, while sulfur and vulcanizing agent P, which have been used previously, -The quinone dioxime is not vulcanized well in the foam composition mainly composed of EVA and PE mixture in the present invention, the process oil as a softening agent is also used in the composition of the present invention is a disadvantage that the processability, compatibility and releasability is reduced there was.

The body frame soundproof foam 1 made of the composition constituted as described above is formed of a support plate 5 of various forms, wherein the foam is formed of double upper and lower plates 5a and 5b similar to the spaces between the body frames 3. Inserted or fixed to the groove 7 or the inner surface, and then inserted into the air gap between the body frame 3 and fixed to the wall of the frame 3 of the vehicle body using the various types of elastic fasteners 6 of the support plate 5. When the foam itself is screwed to the wall with bolts, the vehicle body is completely assembled and the foam is foamed and adhesively cured by heating during vehicle electrodeposition coating, so the foam (1) can be easily replaced without requiring complicated processes and materials. It is characterized in that the soundproofing effect of the frame 3 of the vehicle body can be maximized by allowing the foaming to be securely and completely fixed so as not to be separated.

In the above, the mixture of EVA and PE as the main material of the foam composition of the present invention is that EVA and PE have excellent hot melt adhesiveness (hot melt adhesiveness), so that the foams made of them using the properties of the metal sheet of the vehicle body frame It is inserted or fixed to the support plate (5) to be supported on, and then it is inserted into and fixed to the gap between the body frames or the foam (1) itself is fixed to the wall of the frame by a mechanism such as a bolt to be heat-bonded and hardened by heat during electrodeposition coating. In this case, the EVA has excellent hot melt adhesiveness and PE which improves the crosslinking density, and has strong adhesion to the metal by heat, and has excellent crosslinkability by the vulcanizing agent and foamability by the foaming agent. When it is added more than 85 ~ 95wt%, the hot melt adhesiveness is good but the curing speed is delayed. The impact resistance is lowered, and in the case of PE, the addition amount of EVA decreases relative to the addition amount of 5-15 wt%, so that the heat-melt adhesion property is lowered. This results in an increase in defects due to such excess of EVA.

In addition, the mixture of EVA and PE at 50 to 60 wt% with respect to the total weight of the composition is intended to improve foamability even without a foaming aid, that is, above that, the foaming is delayed or suppressed, and the vulcanization (crosslinking) density is lowered. This is because the foaming speed is too fast and vigorous and does not match the electrodeposition coating time.

The addition of 2-10 wt% of 2,2'-azoisobutyronitrile as a blowing agent is the most suitable blowing agent for EVA and PE, and the electrodeposition without the need for a separate blowing temperature and foaming time control agent is required. In order to make foaming according to the time and temperature at the time of coating, the foaming power is significantly lowered in the amount below the added amount, and in the above amount, the foaming power is not foamed in accordance with the electric coating condition, and foamed and hardened in advance. Peeling phenomenon may occur.

In the present invention, as a vulcanization accelerator, organic peroxides such as tertiary-butyl hydroperoxide or cbenhydro peroxide are most suitable for crosslinking the radical structure of EVA and PE, and other vulcanizing agents are not well crosslinking. Or a slow curing or no curing reaction, and the addition amount is most suitably 1 to 2wt%, and above that, the vulcanization is too fast and the vulcanization (crosslinking) is slower, so that the hot melt adhesion and curing rate It is difficult to match the temperature and time during electrodeposition coating.

In addition, by using polyethylene wax or paraffin wax as the softening agent in the present application, the processability of the sheet, the compatibility of the composition, the mold release property and the flexibility of the sheet, which cannot be obtained by the addition of process oil, are uniformly obtained. It is most preferable to set it as 8 wt%, and when adding more or less, there existed a tendency for compatibility, mold release property, flexibility, and workability to fall.

Since the two materials are hot-melt adhesive (heat-melt adhesive) according to the use of EVA and PE as the main materials in the above, the present invention does not need to add an adhesive material to the foam composition or apply the surface of the prepared foam to the present invention. Grooves 7 formed on the outer circumferential surface of the support plate 5 for fastening the foam 1 molded from the composition into the elastic fastening pieces 6 in the voids between the vehicle body frames 3 or the plate 5a and 5b which are doubled up and down. ) Is inserted into or fixed to an inner surface of a single plate (not shown), and then the support plate 5 is inserted into the air gap between the frames 3 of the vehicle body to be fixed to the vehicle body frame 3 with the elastic fastening pieces 6 or to a foam ( 1) If the body is fixed (not shown) to the vehicle body frame 3 by bolts or the like, after the assembly of the vehicle body is completed, the vehicle body is foamed by the heat that is heated during the electrodeposition coating at high temperature. It is strongly bonded by the adhesive force, so that the gap between the frames of the vehicle body is firmly blocked, and thus the resonance phenomenon caused by the driving noise such as the engine noise of the vehicle or the wind noise due to the tire and the driving is also prevented.

Claims (1)

A composition of a vehicle body frame sound insulation foam which is interpolated or fixed to a support plate to block the space between the vehicle body frames or bolted to the body frame wall by itself as a support plate, wherein stearic acid, zinc oxide, and colorant are used as processing aids in the main material of the composition. Low carbon black, clay as a flow inhibitor, calcium carbonate as a filler, process oil as a softener for processing, sulfur as a vulcanizing agent and P-quinone dioxime as a vulcanizing agent and OBSH (Oxy Bisbenzene Sulfonyl Hydrazide) or DPT as a blowing agent In the composition of the foam soundproofing agent for the frame of the vehicle body, 50 to 60 wt% of the mixture of 85 to 95 wt% of ethylene vinyl acetate copolymer (EVA) and 5 to 15 wt% of either low density or high density polyethylene (PE) as the main material as a main material. 2 to 2 azoisobutyronitrile was added thereto as a blowing agent, based on the total weight of the composition, and 7 to 10 wt% of the vulcanization and vulcanization accelerator was selected from tertiary-butyl hydroperoxide or kbenhydroperoxide. 1 to 2 wt% of an organic peroxide is added to the total composition weight, and then 3 to 8 wt% of the total composition weight is added to any one selected from polyethylene wax or paraffin wax as a softener. Composition of the frame sound-proofing agent.