JPS58136620A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:An injection-moldable epoxy resin composition useful in the preparation and sealing of electric and electronic parts and in the production of mechanical parts, prepared by mixing an epoxy resin, a novolak resin and urea. CONSTITUTION:The titled composition is obtained by mixing 100pts.wt. epoxy resin (e.g., polyglycidyl ether) with 20-120pts.wt., pref. 40-100pts.wt., novolak resin (e.g., one prepared by condensing a phenol with formaldehyde in the presence of an acid catalyst, preferably one having 2-10 nuclei and a softening point of about 50-140 deg.C) and 0.1-20pts.wt., pref. 1-10pts.wt., urea. It is further possible to accelerate curing in the mold without adversely affecting the stability in the cylinder of an injection molding machine by adding dicyandiamide. The amount of dicyandiamide added is preferably about 0.1-5pts.wt. per 100pts.wt. epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an epoxy resin composition that is highly stable in the screw of an injection molding machine and can be injection molded.

Because of its excellent electrical performance and adhesive properties, epoxy resin is used to seal elements such as coils, transistors, diodes, IC1 or iL, and S-electronic components. It is used for manufacturing. For example, an epoxy resin composition made by blending an epoxy resin and a phenol/novolac resin as a curing agent with an accelerator such as a tertiary amine or imidazole is poured into a transfer spot, and after melting, it is poured into a mold using a plunger. Through the discontinuous transfer molding method,
Electrical/electronic and child parts are manufactured by sealing coils, etc. However, this method has many problems, such as very low productivity, and this accelerator system causes large shrinkage during curing, causing distortion in the product.

In order to improve productivity, the inventor of the present invention considered manufacturing the electric/electronic parts by injection molding and tested various compositions, and found that the temperature dependence of gelation in the above epoxy resin composition was Due to its small size, gelation progresses in the cylinder of the injection molding machine, which is heated to approximately 60-120℃, and the stability is poor, such as not being able to maintain sufficient fluidity, making it difficult to continuously mold by injection molding method. Met. However, the inventor has discovered that along with novolak resin as a curing agent,
A composition containing a small amount of urea is highly stable, maintains sufficient fluidity for a sufficient period of time in the cylinder of an injection molding machine heated to approximately 60-120°C, and can be injection molded.
The present invention was completed by discovering that it hardens rapidly in a mold heated to a higher temperature and has less shrinkage, and that by further post-curing after molding, good electrical and electronic parts with less distortion can be obtained. This is what I came to do.

That is, the present invention uses 20 to 120 parts by weight of novolac resin and 0.1 parts by weight of urea to 100 parts by weight of epoxy resin.
The gist of the invention is an injection moldable epoxy resin composition containing up to 20 parts by weight.

The present invention will be explained in more detail below.

The epoxy resin used in the present invention includes, for example, 1.
A compound having a 2-epoxyethyl group, especially l
, 2-epoxyethyl group is preferably bonded to an oxygen, nitrogen or sulfur atom. Examples of such epoxy resins include polyglycidyl ethers, which are then treated with an alkali or acid catalyst in the presence of an alkali or acid catalyst. It is obtained by reacting a compound having at least two free alcoholic and/or phenolic hydroxyl groups in one molecule with epichlorohydrin or glycerol dichlorohydrin. The ethers include ethylene glycol, diethylene glycol, triethylene glycol, higher polyoxyethylene glycol, propane-1,2-diol, polyoxypropylene glycol, propane-1,3-diol, butane-1
, 4-diol, polyoxybutylene glycol, pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-triol, glycerol,
1% 1.1-trimethylolpropane, Pentaerys I
Acyclic alcohols such as J)-ol, poly(epichlorohydrin); resorcinol, cutol (quini
°Col), bis(4-hydroxycyclohexyl)-methane, 2,2-bis(4-hydroxycyclohexyl)
Cycloaliphatic alcohols such as propane, 1,1-bis(hydroxymethyl)cyclohexene-3; N%N-bis(
2-hydroxyethyl)anisu7.4.4'-bis(2
-Hydroxyethylamino)diphenylmethane can be obtained from alcohols having an aromatic nucleus, etc.

Alternatively, mononuclear phenols such as resorcinol, hydroquinone, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)sulfone, 1.11
．． 2,2-tetrakis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A), 2,2-bis(3,5-dibromo-4-hydroxy phenyl)
Obtained from polynuclear phenols such as polynuclear phenols, formaldehyde, acetaldehyde, chloral, aldehydes such as flumethylaldehyde and phenols such as phenol, 4-chlorophenol, 2-methylphenol, o-cresol, 4-tert-butylphenol. It can also be obtained from sources such as Novolac.

Some poly(N-glycidyl) compounds contain at least two amino acids, such as epichlorohydrin and aniline, n-butylamine, bis(4-aminophenyl)methane, and bis(4-methylaminophenyl)methane. N%N'-diglycidyl derivatives of amines containing hydrogen atoms, triglycidyl isocyanurates, and cyclic ureas such as ethylene 7-urea, 1,3-propylene urea, hydantoins such as 5,5-dimethylhydantoin; Also included are those obtained by dihydrocrination with reaction products of.

Examples of poly(S-glycidyl) compounds include dithiol dithiols such as ethane-1,2-dithiol and bis(4-mercaptoethylphenyl) ether.
There are S-glycidyl derivatives.

Also included are polyglycidyl esters obtained by reacting a compound having two or more carboxyl groups in one molecule with epichlorohydrin or glycerol dichlorohydrin in the presence of an alkali. Such polyglycidyl esters include aliphatic acids such as oxalic acid, acetic acid, glutaric acid, adipic acid, pinelic acid, suberic acid, azelaic acid, sebacic acid, trimerized or trimerized linoleic acid. Polycarboxylic acids; cycloaliphatic polycarboxylic acids such as tetrahydroheptalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid, 4-methylhexahydrophthalic acid; such as phthalic acid, isophthalic acid, terephthalic acid It can be obtained from aromatic carboxylic acids.

The terminal 1,2-epoxide group has various hetero (hθte)
Epoxy resins bonded to the ro) element can also be used. Examples of these include p-aminophenol N, N
, 0-triglycidyl derivatives, or glycidyl ether-glycidyl esters of salicylic acid or phenolphthalein. In the present invention, a mixture of these epoxy resins can be used. In the present invention, glycidyl ether of novolac obtained by reacting phenol or cresol with formaldehyde is particularly preferred because the cured product has good heat resistance.

The epoxy equivalent is preferably 100 to 300.

Next, the novolac resin referred to in the present invention includes phenol, alkyl-substituted phenol, such as 0-cresol, p-
It is obtained by condensing phenols such as cresol, t-butylphenol, cumylphenol, and vinylphenol with formaldehyde under an acidic catalyst, and among them, it has 2 to 10 nuclei and a softening point of about 50 to 140°C. Preferably.

Novolac resins are required as curing agents in the compositions of this invention.

The composition of the present invention also contains a small amount of urea.

Urea has a hardening accelerating effect.

The blending ratio of the composition is 20 to 120 parts by weight, preferably 4 parts by weight, of novolak resin per 100 parts by weight of epoxy resin.
0 to 100 parts by weight is used. Curing is sufficiently achieved with this blending amount, and if curing is not achieved with more or less, urea is used in an amount of 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight. . If it is less than 0.1 parts by weight, the curing accelerating effect will be poor, and if it exceeds 20 parts by weight, curing will proceed too rapidly, resulting in large shrinkage of the molded product, and the molded product will also become brittle.

Furthermore, in the present invention, by further adding dicyandiamide, curing within the mold can be promoted without impairing stability within the cylinder of the injection molding machine. In this case, the amount of dicyandiamide blended is preferably about 01 to 5 parts by weight per 100 parts by weight of the epoxy resin.Additives commonly used in epoxy resin molding materials are also optionally added to the injection molding composition. You can also. For example, fillers such as mica, short asbestos fibers, calcium carbonate, alumina, silica, talc, glass fibers or aluminum hydroxide can be added to
00 parts by weight, about 01 to 10 parts by weight of a mold release agent such as carnauba wax or stearic acid, about 01 to 5 parts by weight of a coloring agent such as carbon black, or a compound such as antimony oxide or tetrabromobisphenol A. 10
An appropriate amount of flame retardant such as genated polyhydric phenol can also be blended.

The components in the composition are mixed, for example, using rolls such as two rolls, a twin-screw extruder, etc.
After kneading at a temperature of °C, it is ground after cooling. After triblending at room temperature in a tumbler mixer, the mixture may be compression molded into pellets or granules and supplied to an injection molding device.

As the injection molding device, a known device for thermosetting resin can be used. Since the composition of the present invention is a thermosetting type, it is necessary to use a long press that allows the curing reaction to proceed in a heating cylinder, and on the other hand, it is necessary to increase the molding cycle by making curing in the mold as fast as possible. Preferably, the temperature inside the cylinder or the cylinder head is 60 to 120°C, and the mold temperature is 120 to 200°C.

Hardening in a mold is done to the extent that it can be taken out into the desired shape. The temperature is as described above (120 to 200°C, and the curing time is about 20 seconds to 3 minutes).

Furthermore, the molded product taken out from the mold is usually open,
Vostokairing is performed at a temperature of 100 to 200'C for about 2 to 10 hours to completely cure. As a result, a molded product with less cracks and less distortion after curing can be obtained.

As described above, the composition of the present invention can be injection molded, has greatly improved productivity, and can be cured with less shrinkage, cracks, distortion, etc. than when molded by conventional transfer molding manufacturing methods. It is something that gives something.

The composition of the present invention is suitably used in the production of electric/electronic parts, sealing, production of mechanical parts, and other production of epoxy resin molded products by injection molding.

It goes without saying that the composition of the present invention can also be applied to transfer molding.

Example 1 A compound with the following composition was kneaded with two rolls to give a powder of 90 to 100.
After cooling, the mixture was ground into granules, and the gelation time was measured using the Gravender Plastograph method (using Labo Plastomill manufactured by Toyo Seiki Co., Ltd.) (Table 1).

EOCN-1028 (Nippon Kayaku Co., Ltd. product, 0-cresol novolac epoxy resin, epoxy equivalent 210-2
40) 30 parts by weight phenol novolac resin (Showa Union product, OTM-0
07, softening point 85-95°C) 13.5 parts by weight Fuselex RD-8 (■Tatsumori product, fused silica) 7
0 parts by weight Stearic acid 0.5 parts by weight Carbon black 0.3 parts by weight Urea 3 parts by weight Comparative Example 1 In the formulation of Example 1, 2-ethyl-4-methyl-imidazole-azine complex ( The gelation time was measured in the same manner as in Example 1 except that 1 part by weight (product of Shikoku Kasei Co., Ltd.) was used.

The results are shown in Table 1.

Table 1 It is clear that the composition of Example 1 has a greater temperature dependence of gelation than the composition of Comparative Example 1 and is suitable for injection molding.

Example 2 and Comparative Example 2 The following formulation (parts by weight) was kneaded for 5 minutes using two rolls at a temperature of 90-100°C, cooled, and ground into granules to obtain a molding material. Ta.

In Example 2, the obtained molding material was injection molded using a Thermosetter injection molding machine (Thermosetter, mold clamping pressure 100 t) under the following conditions.

Cylinder head temperature: 80'C.

Screw rotation speed: 37r, p, m.

Injection pressure 4ooK//crn2 Injection speed 7.3 cml sec Mold temperature 180'c Mold holding time (
Compatible with molding cycle) 50sθC, then molded product 160℃
A test piece based on JIS K 6911 was prepared by post-keying for 8 hours.

Regarding Comparative Example 2, injection molding was attempted under the same conditions as Example 1, but the viscosity of the composition increased significantly in the injection molding machine.
Continuous molding was difficult. Therefore, transfer molding was performed under the following conditions (using a transfer molding machine manufactured by Matsuda Kikai, mold clamping pressure of 50 t).

Plunger pressure 70 Ky/cm2 Plunger descending speed 3 cml sec
Mold temperature: 180°C Mold holding time: 180 seconds Then, the molded product is
Post-curing was performed at 60° C. for 8 hours, and a test piece was prepared.

The physical properties of the test pieces obtained in Example 2 and Comparative Example 2 were measured, and the results are shown in Table 2. Measurement is JIS K
6911. However, the glass transition temperature was determined by a linear expansion coefficient measurement method.

From the above results, the molded product of Example 2 has less curing shrinkage than the conventional molded product of Comparative Example 2.

Table 2 Example 3 In Example 1, instead of KOON-1028, T
! , OCN-103El (Nippon Kayaku Co., Ltd. product, O-cresol novolac epoxy resin, epoxy equivalent ?10
-235), and the gelation time was measured in the same manner as in Example 1 except that The results are shown in Table 3.

Procedural amendment dated March 13, 1982 1. Indication of the case Patent Application No. 18579 of 1985 2. Name of the invention Epoxy resin composition & person making the amendment Relationship to the case Patent applicant address Kasumigaseki, Chiyoda-ku, Tokyo 3-2-5 Name (5
8B) Mitsui Oil - Kagaku Kogyo Co., Ltd. Representative Shimono Tanawa 4, Agent Address 1601-63 Nagara, Hayama-machi, Miura-gun, Kanagawa Prefecture
Column ``Detailed Description of the Invention'' of the specification to be amended (1) ``Epoxyethyl group'' on page 3, line 15 of the specification is amended to ``epoxyprobyl group.''

(2) “Dihydrocrination” on page 6, line 8 of the same page
is corrected as "dihydrochlorination".

(3) In the first line from the bottom of page 15, ``Using and otherwise the same as Example 1'' was replaced with ``The same as Example 1 except that dicyandiamide was used and 1 part by weight of dicyandiamide was further blended.''"Go to ``,'' he corrected.

Agent: Patent attorney Masao Inoue

Claims (1)

Claims: 1. An injection moldable epoxy resin composition comprising 20 to 120 parts by weight of novolac resin and 0.1 to 20 parts by weight of urea to 100 parts by weight of epoxy resin. 2. An injection moldable epoxy resin composition comprising 20 to 120 parts by weight of novolac resin, 1 to 20 parts by weight of urea o, and 1 to 5 parts by weight of dicyandiamide o to 100 parts by weight of epoxy resin.