JPH0433289B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an adhesive thermosetting resin molded article having electrical conductivity and heat resistance. (Prior art) Conventionally, when parts are bonded and fixed, a liquid or putty-like adhesive is created using a thermosetting resin and applied to the adhesive area, but the adhesive itself The shape of the adhesive is indeterminate, and a jig is required to temporarily position the adhesive area until the adhesive is cured and adhered. Furthermore, when thermosetting powder adhesives are used, a method is used in which they are preformed by means such as compression to help position the parts to be bonded, but this preformed product has weak strength and cannot be used for parts. There are problems in fixing the material, and since the material is powdered, the state after melt bonding contains many bubbles, so it cannot be said to be a highly reliable bonding method. On the other hand, hot-melt type adhesives using thermoplastic resins have good processability and are widely used, but due to their thermoplastic properties, they cannot be heat-resistant adhesives. Recently, there has been an increase in the need to bond small and minute parts such as electronic parts, but it is not possible to use the conventional adhesives mentioned above and apply them only to such relatively small areas. With difficult, liquid adhesives, extrusion or shortages can occur. In addition, in the case of a preformed thermosetting adhesive, it can be shaped into a shape that matches the area to which it is applied, but as mentioned above, it has the problem of low strength. Furthermore, when a thermoplastic resin is used, the above-mentioned shaping is easy, but there remains a drawback of low heat resistance. To improve this problem, adhesive resin molded products are known, for example, described in JP-A-55-90549 and JP-A-56-135580, in which a thermosetting epoxy resin and a thermoplastic resin are combined. Although the mechanical strength of the molded product has improved, its solvent resistance deteriorates and heat resistance inevitably decreases due to the addition of thermoplastic resin, which limits its range of use. Furthermore, in JP-A-56-135579, acrylonitrile containing a carboxyl group is added to a thermosetting epoxy resin.
Adhesive resin molded products containing thermosetting rubber such as butadiene copolymer have been described, but although this molded product has improved shape retention, it has poor adhesion and electrical properties, and It has the disadvantage that molding workability deteriorates because the melt viscosity increases during molding. Furthermore, none of the above-mentioned known techniques disclose or suggest the inclusion of a conductive filler. On the other hand, JP-A No. 58-225120 discloses an epoxy resin composition for semiconductor encapsulation which is made by mixing a bisphenol epoxy resin and a polyester elastomer with a mixture of a novolac type epoxy resin, a phenol novolac resin curing agent, and silica powder. described,
It is disclosed that other fillers such as carbon fibers can be used in combination. However, this technology aims to improve heat resistance, water resistance, and crack resistance using the above-mentioned specific composition, and also does not involve molding it into a shape that matches the required application area. There is nothing to write about. (Problems to be Solved by the Invention) An object of the present invention is to provide an adhesive thermosetting resin molded article having excellent conductivity, heat resistance, mechanical strength, and adhesiveness. Another object of the present invention is to provide an adhesive thermosetting resin molded article having excellent solvent resistance, electrical properties, and molding workability. (Means for Solving the Problems) The present invention consists of a long-chain amine with a molecular weight of 1,000 to 50,000 and having at least two or more active hydrogen atoms on nitrogen in one molecule, and an epoxy resin having at least three or more active hydrogen atoms in one molecule. By addition-reacting an epoxy resin having a group at an equivalent ratio of active hydrogen (A) and epoxy group (B) at (B)/(A) = 3 to 30, or with a phenolic hydroxyl group-terminated prepolymer and a trifunctional A polymer having a number average molecular weight of 2,000 to 50,000, an epoxy equivalent of 120 to 5,000, and having an average of at least two or more terminal epoxy groups in one molecule, obtained by reacting with an epoxy compound having the above epoxy groups. The present invention relates to an adhesive thermosetting resin molded article obtained by molding a composition in which a conductive filler and a curing agent are blended into a molecular weight polyfunctional epoxy resin in a substantially uncured state. The conductive adhesive thermosetting resin molded article of the present invention can be easily molded into a shape that matches the required application location, and has good heat resistance, mechanical strength,
Excellent electrical properties, etc. In the present invention, a substantially uncured state means a state where crosslinking has partially progressed but has not been completed. In the present invention, the high molecular weight polyfunctional epoxy resin includes, for example, a long chain amine with a molecular weight of 1,000 to 50,000 and having at least two or more active hydrogen atoms on nitrogen in one molecule, as described in Japanese Patent Application No. 1987-201554.
Obtained by addition reaction of an epoxy resin having at least three or more epoxy groups in the molecule at an equivalent ratio of active hydrogen (A) to epoxy group (B) of (B)/(A) = 3 to 30. Mention may be made of epoxy resins. The long-chain amine used in the above refers to a long-chain amine having at least two active hydrogen atoms on nitrogen in one molecule and a molecular weight of 1000 to 50000, preferably 2000 to 5000.
20,000 compounds, such as polyurethane,
Polyurethaneurea, polyurea, polyamide resin, urea resin, polysiloxane having an amino group and/or imino group, polyimide resin having an amino group and/or imino group, polyamideimide, polyvinylamine, polyisopropenylamine, polyethyleneimine, poly Examples include triethyleneimine and polyaminostyrene, but preferably 2 active hydrogen atoms on nitrogen in one molecule.
Active hydrogen (C) and epoxy group
A long-chain amine (E) obtained by addition reaction with (D) at an equivalent ratio of (C)/(D)>1 is used. If the molecular weight of the long-chain amine is less than 1,000, the mechanical properties of the cured product will not be sufficient, and if it is greater than 50,000, it will have a high melting point, and the epoxy group in the next step will be reduced by at least 3.
Addition reaction with epoxy resins having more than 100% of epoxy resins becomes difficult. Representative examples of amines having two active hydrogens on nitrogen in one molecule include aniline, toluidine, ethylaniline, 0-3-xylidine, N,
N'-diphenyl-1,2-diaminoethane, N,
Examples include, but are not limited to, N'-dimethyl-p-phenylenediamine and aminophenol. Examples of epoxy resins having two epoxy groups in one molecule include bisphenol A type epoxy resin, halogenated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, Examples include cyclic epoxy resins, silicon-containing epoxy resins, phosphorus-containing epoxy resins, etc.
Alternatively, they can be used in combination. In addition, 1
The epoxy resin having two epoxy groups in the molecule is not limited to these. Epoxy resins having at least three or more epoxy groups in one molecule to be subjected to an addition reaction with the above-mentioned various long-chain amines include phenol novolac type epoxy resins, cresol novolac type epoxy resins, and brominated phenol novolac type epoxy resins. , glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, p-aminophenol glycidyl ether diglycidylamine, tetraglycidyl-1,3-bis(aminomethyl)cyclohexane, 2,6-(2,3 -epoxypropyl) phenylglycidyl ether, tetrakishydroxyphenylethane tetraglycidyl ether, trihydroxyphenylpropane triglycidyl ether, polyallylglycidyl ether, triglycidyl isocyanurate, bis(4-diglycidylaminophenyl)methane, etc. However, preferably a novolak type epoxy resin is used. These epoxy resins and long-chain amines are mixed in such a way that the equivalent ratio of the active hydrogen (A) of the amine to the epoxy group (B) of the epoxy resin is (B)/(A)=3 to 30, preferably (B)/(A). )=5～
The desired high molecular weight polyfunctional epoxy resin can be obtained very easily by carrying out the addition reaction in step 15. If (B)/(A) is less than 3, there is a possibility of partial gelation during synthesis, and if it is greater than 30, sufficient mechanical properties of the cured product cannot be obtained. In addition, as another example of the above-mentioned high molecular weight polyfunctional epoxy resin, a phenolic hydroxyl group-terminated prepolymer and 3
Examples include epoxy resins obtained by reacting with epoxy having a functional or higher epoxy group. Examples of the above prepolymers include those obtained by reacting bisphenol A with Epicote 828, ESB-400, etc.; examples of epoxies having trifunctional or higher functional epoxy groups include o-cresol novolac type epoxy, phenol novolac type epoxy, Examples include ELM-120 and ELM-434. If the number average molecular weight of the above epoxy resin is less than 2,000, the strength in the uncured state will be weak; if it exceeds 50,000, the melting temperature of the resin will be in the high temperature range (200℃
above), which is not desirable. Epoxy equivalent is 120
If it is less than that, the reactivity will be too high and synthesis will be difficult, and it will harden before being melted in the melt bonding process.
If it exceeds 5000, the crosslinking density of the cured product will be low and the heat resistance of the cured product cannot be expected. Furthermore, if one molecule does not have at least two or more terminal epoxy groups on average, three-dimensional crosslinking will not proceed during the curing reaction, resulting in low heat resistance. The above-mentioned high molecular weight polyfunctional epoxy resin of the present invention has an average molecular weight of 2000 or more, so it is different from conventional Epicoat.
Unlike 1001, 1004, etc., and because the number of terminal epoxy groups in one molecule is 2 or more, conventional Epicoat
It is also different from 1007, 1009, etc. Examples of conductive agents that can be added to the above-mentioned high molecular weight polyfunctional epoxy resin include gold, silver, copper, aluminum, nickel, carbon, conductive calcium carbonate powder, glass beads coated with silver, glass fibers, and carbon fibers. , graphite, etc. As the curing agent used in the present invention, various known compounds can be mentioned, and for example, amines, acid anhydrides, phenols, etc. can be used.
Specific examples of amines include diethylenetriamine, triethylenetetramine, methylhexamethylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenyl sulfone,
xylene diamine, metaphenylene diamine,
4,4'-methylenebis(2-chloroaniline) and adducts of these with epoxy resins, etc. Specific examples of acid anhydrides include phthalic anhydride, tetrahydrophthalic acid, hexahydrophthalic acid, tetrachlorophthalic anhydride, and anhydride. Specific examples of phenols include methylnadic acid, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, etc., and phenol, o-cresol novolak, phenol novolak, etc. The amount of the curing agent to be blended is preferably in the range of 0.7 to 1.2 in terms of equivalent ratio to the epoxy group. When producing the molded article of the present invention, in addition to the above-mentioned high molecular weight polyfunctional epoxy resin, other resins may be used in combination as long as the object of the present invention is not impaired. For example, bisphenol type epoxy resins, phenoxy resins, polyamide resins, polycarbonate resins, polyester resins, polyolefin resins, vinyl chloride resins, vinylidene chloride resins, vinyl acetate resins, and polyvinyl alcohol resins having a molecular weight of 400 or more, used alone or in combination or in combination. A polymer resin can also be used in combination. The amount of these combined resins is preferably 95 parts by weight or less based on 100 parts by weight of the polyfunctional epoxy resin. Further, among the above-mentioned combined resins, the proportion of thermoplastic resin used in combination is preferably 30 parts by weight or less, particularly preferably 5 to 25 parts by weight. When the combined use ratio is within the above range, it is preferable in terms of heat resistance, shape retention of uncured molded products, etc. The present invention also includes various known additives, such as curing accelerators, catalysts (dicyandiamide, tertiary amines, imidazole, Lewis acid amine complexes, etc.),
Fillers (inorganic fillers such as mica, glass fleta, glass powder, glass fiber, carbon fiber, silica, talc, calcium carbonate; organic fillers such as aramid fibers), pigments (red iron, titanium white, etc.), lubricants (stearin) Zinc acid, wax, etc.), other silane coupling agents, etc. can be added as necessary. In the present invention, a high molecular weight polyfunctional epoxy resin containing the conductive agent, a curing agent, additives, etc. are mixed, kneaded, cooled, coarsely pulverized, and classified into powder diameters of about 1 to 3 mm. injection molding, extrusion molding,
By molding in a substantially uncured state by a molding method such as transfer molding, compression molding, or casting, the desired adhesive thermosetting resin molded article can be obtained. The amount of the conductivity filler is 5 to 60 parts by volume based on 100 parts by weight of the total mixture obtained by mixing the epoxy resin containing the conductivity filler, curing agent, additives, etc.
The amount is preferably 20 to 50 parts by volume. The reason why the blending amount is expressed as parts by volume is because the specific gravity varies greatly depending on the material. When the blending amount is within the above range, it is preferable in terms of volume resistivity, green strength of uncured molded product, and adhesive strength. In addition, samples of 5 x 10 x 70 mm are made from all the above compounds by injection molding, transfer molding, casting, etc., and the bending strength of the samples is 50 Kg/cm ² or more, preferably 100 Kg/cm ² or more. This is suitable, and in that case a molded article can be easily made in an uncured state. The shape of the molded body can be any arbitrary shape, such as a rod shape, a ring shape, a branched pipe shape,
Examples of the shape include a cup shape, a sheet shape, a film shape, a hollow pipe shape, a pellet shape, and a semicircular donut shape. The method of using the molded article of the present invention is, for example, by placing it, inserting it, and fitting it into the bonded part of the parts to be bonded, and then heating it to a temperature equal to or higher than the melting point of the molded article, so that the molded article is melted and bonded and further hardened. (Effects of the invention) According to the molded article of the present invention, it is suitable for quantitative management of adhesive (=volume), positioning of objects to be adhered (=shape), and adaptation to automation such as robots (solid, high strength). This makes assembly by gluing very easy.
In addition, since the main component is epoxy resin, it has heat resistance,
It also has excellent chemical resistance, solvent resistance, electrical properties, adhesion, and adhesion. Furthermore, among electrical and electronic components, it is particularly suitable for applications such as Dan bonding materials for IC sealing, where the adhesive itself is required to have heat resistance and conductivity. (Example) Reference examples and examples will be described below.
Note that "parts" simply means parts by weight. Reference example 1 Epoxy resin (A) 500g of Epicoat 828 [bisphenol A type epoxy resin, epoxy equivalent 189, manufactured by Yuka Ciel Epoxy Co., Ltd.] was charged in a reactor, and the temperature was raised to 150°C.
While stirring, 141.7g of aniline was added dropwise over 1 hour.
After the dropwise addition was completed, heating and stirring was continued for an additional 0.5 hour. During the 1.5 hours required for the addition reaction, the temperature was 150-190℃.
The completion of the reaction was confirmed by infrared absorption spectrum (disappearance of absorption at 910 cm ^-1 by epoxy groups). The amine equivalent of this sub-amine prepolymer was 2,700. This material was crushed to a size that could pass through a 3 mm mesh. 300 g of ESCN-220HH [cresol novolak type epoxy resin, epoxy equivalent 220, manufactured by Sumitomo Chemical Industries, Ltd.] was charged into a reactor, the temperature was raised to 180°C, 283.2 g of pulverized amine-terminated prepolymer was added, and the temperature was lowered. The mixture was maintained at 180 to 190°C and stirred for 1.5 hours to carry out an addition reaction. Completion of the reaction was confirmed when the amine equivalent weight became practically zero. The epoxy equivalent of the obtained epoxy resin was 465. The number average molecular weight was 7000-8000. Molecular weight measurement was performed using GPC manufactured by Waters. The bending strength of this resin was measured using a Shimadzu IM-100 autograph at a head speed of 5 mm/min and a span of 56 mm (hereinafter referred to as
It was measured at 252 kg/cm ² (same). Reference Example 2 Epoxy resin (B) A phenolic hydroxyl group-terminated prepolymer with a molecular weight of 5000 to 6000 made by reacting bisphenol A and Epicote 828 under a catalyst, and o-cresol novolak type epoxy ESCN-220L (manufactured by Sumitomo Chemical Co., Ltd.) ) in such a way that the equivalent ratio of phenolic hydroxyl group to epoxy group is 1:7 and reacted at 160 to 180°C to obtain an epoxy equivalent of 745, a number average molecular weight of 8000 to 9000,
An epoxy resin with a bending strength of 104 Kg/cm ² was obtained. Examples 1 to 5 To 100 parts of epoxy resin (A), 11 parts of diaminodiphenylmethane (DDM) and 10 parts of polyester elastomer are blended as a curing agent. Furthermore, as a conductive agent, 350 mesh of nickel powder was added at 5% (48 parts), 10% (99 parts), and 20% of the total volume.
(222 parts), 30% (381 parts), and 60% (1335 parts) were added, and after melt-kneading in a kneader at 100℃ for 5 minutes and then melt-kneading at 120℃, extrusion molding was performed to form an uncured rectangular conductive plate. An adhesive thermosetting resin molded article having properties was obtained. This sample piece was placed in two copper plates and heated at 180℃.
The adhesive was cured under pressure for 10 minutes. After curing, the electrical resistance between the copper plates was measured and the volume resistivity was calculated, and the results are shown in Table 1. The electrical resistance value is 16008A manufactured by Yokogawa Huuretsu Card Co., Ltd.
Measured using RESISTIVITY CELL. Furthermore, when the adhesive strength of the cured samples was examined using the following test method, cohesive failure of the resin was observed in all samples. Test method Two sheets of mild steel with a width of 25 mm, a length of 60 mm, and a thickness of 3 mm are heated to 180℃ in an oven.A test piece of 25 mm width and 12.5 mm length is placed between the two sheets of mild steel and heated to 180℃. in 10
The adhesive was allowed to cure for a few minutes. After cooling, a tensile shear test was conducted using an Instron tensile tester. Examples 6 to 9 To 100 parts of epoxy resin (B), 7 parts of diaminodiphenylmethane (DDM) and 10 parts of polyester elastomer are blended as a curing agent. Furthermore, carbon black powder (manufactured by Tokai Carbon Co., Ltd., Toka Black #4500) was added as a conductive agent at 5% (10 parts), 10% (20 parts), and 20% (45 parts) of the total volume.
and 30% (77 parts), melt-kneaded in a kneader at 100°C for 5 minutes, then extruded at 120°C,
An uncured rectangular plate-shaped conductive adhesive thermosetting resin molded body was obtained. This test piece was adhesively cured in the same manner as in Example 1, and the volume resistance was measured. The results are shown in Table 1.
Further, when the adhesive strength was examined in the same manner as in Example 1, cohesive failure of the resin was observed in all samples, and each sample had sufficient adhesive strength. 【table】

Claims (1)

[Claims] 1. A long chain amine with a molecular weight of 1,000 to 50,000 that has at least two active hydrogens on nitrogen in one molecule and an epoxy resin that has at least three or more epoxy groups in one molecule are combined with active hydrogen (A) and epoxy group (B) at an equivalent ratio of (B)/(A) = 3 to 30, or by reacting a phenolic hydroxyl group-terminated prepolymer with an epoxy compound having a trifunctional or more functional epoxy group. The number average molecular weight obtained by this is 2000~50000 and the epoxy equivalent is 120~
5000, which is formed by molding a composition in a substantially uncured state, which is a composition in which a conductive filler and a curing agent are blended with a high molecular weight polyfunctional epoxy resin having an average of at least two or more terminal epoxy groups in one molecule. Adhesive thermosetting resin molded body.