JP2008285612A - Hot melt resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic resin composition with reduced deterioration after a long time exposure to high temperature, releasable if required, useful as a sealant etc., of a frame of an electronic control unit for an automobile. <P>SOLUTION: The hot melt resin composition 1 is characterized by comprising a styrene based block copolymer, tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyethyl]methane, and tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4'-biphenylenediphosphonite. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an elastic resin composition that is less deteriorated even when exposed to a high temperature for a long period of time and can be peeled off as necessary, and is useful for sealing a frame of an electronic control unit for automobiles.

An automobile is equipped with an electronic control unit for optimizing operations such as an engine, an air bag, an anti-lock brake system, and a traction control, and the engine electronic control unit is particularly called an ECU. In the electronic control unit, an electronic circuit board is housed in a frame made of polybutylene phthalate resin (PBT resin), an aluminum frame, or the like, and silicone resin has been used to seal the frame. (Example, Patent Document 1)
Japanese Patent Laid-Open No. 2004-249883

  However, if there is a defect in the electronic circuit board that constitutes the electronic control unit, it cannot be removed if the frame is sealed with silicone resin, so only the defective electronic circuit board can be replaced. First, the entire electronic control unit had to be replaced. As a matter of course, the cost for replacement is expensive, and a normal electronic circuit board is also discarded, which increases the amount of waste.

  Due to such problems, a sealing material that can be peeled off has been demanded, and hot melt resins composed of thermoplastic resins and the like have been studied. On the other hand, in the case of electronic control units installed in automobiles, heat aging resistance is required because they are exposed to high temperatures for a long time, but hot melt resins are less heat resistant than silicone resins, so strength over time The decrease was great and was unsuitable for such applications.

  An object of the present invention is to provide an elastic composition which is less deteriorated even when exposed to a high temperature for a long time and can be peeled off as necessary.

  The present invention relates to a styrenic block copolymer, tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] methane, and tetrakis (2,4-di-t-butyl- A hot melt resin composition containing 5-methylphenyl) -4,4'-biphenylenediphosphonite. In particular, when the hot melt resin composition is used for sealing a frame of an electronic control unit for automobiles, a more remarkable effect can be obtained.

  The hot melt composition of the present invention has little deterioration even when exposed to a high temperature for a long period of time, and can be easily peeled off as necessary. Therefore, when used for sealing the frame of an electronic control unit for automobiles, it is excellent in durability, and even if a defect occurs in the electronic circuit board, only the electronic circuit board can be replaced, thus reducing the replacement cost. This eliminates the need to discard even a normal electronic circuit board, thus contributing to the reduction of waste.

  The hot melt resin composition of the present invention contains a styrene block copolymer as a thermoplastic resin. Specifically, SBS (styrene-butadiene-styrene block copolymer), SIS (styrene-isoprene-styrene block copolymer), SEBS (styrene-ethylene-butylene-styrene block copolymer), SEB ( Styrene-ethylene-butylene block copolymer), SEPS (styrene-ethylene-propylene-styrene block copolymer), SEP (styrene-ethylene-propylene block copolymer) SIBS (styrene-isobutylene-styrene block copolymer) Copolymer) and the like.

The hot melt resin composition of the present invention suppresses a decrease in strength when exposed to a high temperature for a long period of time. Therefore, the compound represented by the formula 1; tetrakis [3- (3,5-di-t-butyl) -4-hydroxyphenyl) propionyloxyethyl] methane, and a compound represented by Chemical formula 2; containing tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite It is characterized by doing. In addition to the above compounds, various antioxidants may be used, but excellent heat aging resistance cannot be obtained unless at least the above compounds are used. From the viewpoint of heat aging resistance, the compounding amount of the first-stage compound is preferably 2 to 10% by weight with respect to the entire hot melt resin composition.

  In addition to styrenic block copolymers, terpene resins, terpene phenol resins, rosin resins, petroleum resins and their modified resins, hydrogenated resins and other tackifying resins for the purpose of imparting tackiness, fluidity when melted, Atactic polypropylene, amorphous polyalphaolefin, paraffin wax, low molecular weight polyethylene, low molecular weight polypropylene, oils such as paraffin oil and naphthenic oil, liquid polymers such as liquid polybutadiene and liquid polybutene for non-adhesive control, etc. Can be blended.

  Moreover, fillers, such as talc, clay, silica, calcium carbonate, titanium oxide, may be mix | blended for the purpose of heat resistance, fluidity | liquidity, adjustment of a filling property, or coloring. Furthermore, hollow fillers such as shirasu balloons and glass foams may be blended for the purpose of preventing sedimentation of these fillers, suppressing dimensional changes, and improving heat insulation. Furthermore, adhesion to an adherend such as glass or metal can be greatly improved by blending a silane coupling agent such as amino, vinyl or epoxy.

  The hot-melt composition for sealing according to the present invention can be prepared by kneading each of the above compounded materials while heating with a Banbury mixer, a heating kneader, a uniaxial or biaxial extruder, and the like. The material kneaded under heating is formed into a string shape, an irregular shape, or the like by an extruder, or cast into a shape and molded into each shape, and then heated, melted and applied at the time of use. The Moreover, what was kneaded and melted under heating can also be applied directly.

  The hot melt resin composition according to the present invention is excellent in adhesion and heat resistance to various metals, glass, resin base materials, etc., so that the aluminum sash and the glass plate in the window material for building in addition to the frame of the electronic control unit It is suitable for a connecting portion between a metal opening of a vehicle body and a glass plate in a vehicle, a seal of a connecting portion between a frame body made of aluminum or stainless steel and a glass plate in a solar cell, and the like.

  The method of using the hot melt resin composition according to the present invention is, for example, a method of applying and filling a connecting part such as a frame and a glass plate or a connecting part of an assembled part, or a peripheral part of a one-side assembly part of a frame or a part. It is possible to employ a method in which a glass plate or other parts are brought into contact with and connected to the peripheral edge to which the hot melt composition for sealing is applied after being applied and directly or reheated immediately before attachment or immediately before assembly. Therefore, in addition to processing procedures to be applied at the assembly plant for various products, processing is carried out in which parts applied to one part at another factory are brought in and brought into contact with the part where other parts are applied directly or after reheating. Procedures can also be adopted.

  For application and filling of the hot melt resin composition according to the present invention, hand gun type, block melting type, bulk type and foam type applicator equipment is used. As specific examples of the applicator equipment, a bulk melter BM-505 manufactured by Nordson, Commercially available products such as a tank type applicator MX-4412 for applying a product melted in a tank manufactured by the same company.

  In addition, when mass-manufacturing processed parts in factories, etc., if the discharge part of the hot-melt resin composition coating and filling device is attached to a numerically controlled industrial robot, etc., even for complicated shapes, it can be done quickly. It can be applied, and a significant improvement in production efficiency can be expected.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not restrict | limited to these Examples.

Example 1
Septon 4055 (trade name, manufactured by Kuraray Co., Ltd.) which is a polystyrene-poly (ethylene-ethylene / propylene) block-polystyrene copolymer, Septon which is a polystyrene-poly (ethylene / propylene) block-polystyrene copolymer 2002 (made by Kuraray Co., Ltd., trade name) 3 parts by weight, PW-90 which is a paraffinic process oil (made by Idemitsu Kosan Co., Ltd., trade name), 50 parts by weight, Noryl SA-120 which is a mixture of polyphenylene ether and polystyrene ( GE Plastics, trade name: 7 parts by weight, Glass Bubbles K-37, a hollow filler (trade name, 3M), 10 parts by weight, α-methylstyrene ENDEX155 (Eastman Chemicals, trade name) ) Escole, 6 parts by weight, alicyclic tackifying resin Tsuki ECR-235E (trade name, manufactured by Tonex Co., Ltd.) 25 parts by weight, Dioxide TR92 (product name) manufactured by Titanium Dioxide, 0.6 part by weight, Asahi Thermal Carbon (Asahi Carbon, a carbon black) Product name: 0.03 parts by weight, SOGNNOX 1010 (commercial name, manufactured by Sumitomo Chemical Co., Ltd.), which is a compound represented by Formula 1, 2.5 parts by weight, a compound represented by Formula 2 A hot melt resin composition of Example 1 was obtained by heating and mixing 2.5 parts by weight of GSY-P101 (trade name, manufactured by Sakai Chemical Industry Co., Ltd.) with a sigma blade type kneader.

Example 2
In Example 1, the hot-melt composition of Example 2 was obtained in the same manner as in Example 1 except that the blending amounts of SOGNNOX 1010 and GSY-P101 were each 5 parts by weight.

Comparative Example 1
In Example 1, the blending amount of SOGNNOX 1010 was 3 parts by weight, 3 parts by weight of Sumitizer GP (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant and Tinuvin 144 (trade name, manufactured by Ciba Specialty Chemicals, Inc.) ) A hot melt composition of Comparative Example 1 was obtained in the same manner as in Example 1 except that 1.5 parts by weight was blended and GSY-P101 was not blended.

Comparative Example 2
Comparative Example 2 was performed in the same manner as in Example 1, except that the amount of GSY-P101 was 3.5 parts by weight, 3.5 parts by weight of Sumitizer GP was added, and SOGNNOX 1010 was not added. A hot melt composition was obtained.

Evaluation Assuming the application for sealing the frame material of the electronic control unit for automobiles, the performance was evaluated by the following method.
Each hot melt composition was molded into a length of 19 mm, a width of 20 mm, and a thickness of 2 mm, spacers having a thickness of 1 mm were set at both ends in the width direction, and PBT plates were bonded to both sides to prepare a test specimen. The specimen was fixed in a state compressed by 50% in the thickness direction (thickness: 1 mm) (see FIG. 1) and cured for 1000 hours in an atmosphere of 125 ° C. After curing, it was left to stand in a 23 ° C. atmosphere for 1 day, and in a 23 ° C. atmosphere, the PBT plate was pulled in the 180 ° direction at 20 mm / min, and the tensile shear strength was measured and listed in Table 1.

  Each of the hot melt compositions of the examples showed little decrease in strength even when exposed to a high temperature for a long time. On the other hand, each hot-melt composition of the comparative example has a large decrease in strength, and is not suitable for applications exposed to a high temperature for a long time.

The figure which shows the state which compressed the test body

Explanation of symbols

1 Hot melt composition 2 Spacer 3 PBT board

Claims (2)

Styrenic block copolymer, compound represented by Chemical formula 1; tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] methane, and a compound represented by Chemical formula 2; A hot melt resin composition comprising tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite.

  The hot melt resin composition according to claim 1, wherein the hot melt resin composition is used in an electronic control unit for automobiles.

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