JPH068378B2 - Epoxy resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition, and particularly to an epoxy resin composition useful for optical applications.

[Prior Art] Generally, an acid anhydride-based curing agent is used as an optical epoxy resin composition, and it is necessary to select the type of curing accelerator, the optimum curing condition, or to add an antioxidant or the like. As a result, the transparency and heat resistant color stability of the cured product are improved.

On the other hand, air bubbles and voids remaining in the cured product cause deterioration of transparency and deterioration of mechanical and electrical characteristics due to light scattering. Therefore, normally, an operation of defoaming under reduced pressure is performed before heat curing, but at this time, it is preferable to add a silicone-based or fluorosilicone-based defoaming agent for the purpose of shortening the time of the defoaming operation. It is common. or,
When the cast material has a relatively large capacity, bubbles and voids tend to occur due to internal heat generation during heat curing, and burn coloring tends to occur.To prevent this, reduce the amount of curing accelerator or cure. Attempts have been made to reduce the temperature.

[Problems to be Solved by the Invention] However, when the above-mentioned silicone-based defoaming agent is used for optical applications, there is a drawback that the obtained cured product becomes cloudy or cloudy and impairs transparency. is there. Further, when the amount of the curing accelerator is reduced and the curing temperature is reduced, heat curing for a long time is required and workability deteriorates.

Therefore, the development of an epoxy resin composition that can shorten the time of the vacuum degassing step and heat curing step without impairing the cured material properties such as glass transition temperature, transparency, heat resistance color stability, and moisture resistance of the cured product Was strongly desired.

As a result of intensive studies to solve such a drawback, the present inventors have found that the defoaming property is remarkably improved by the specific addition of a saturated hydrocarbon and a polymer surfactant, and further a specific polyhydric alcohol in combination. However, it was found that heat generation during curing is suppressed and the curing time is shortened, and that a cured product excellent in various properties such as transparency, heat resistant color tone stability, and moisture resistance can be obtained, and based on such findings, The invention was completed.

That is, an object of the present invention is to provide a novel and useful epoxy resin composition having improved workability and particularly suitable for optical applications.

[Means for Solving the Problems] The epoxy resin composition according to the present invention is a composition that is liquid at room temperature and contains an epoxy resin, an acid anhydride-based curing agent, and a curing accelerator. And a saturated hydrocarbon having a freezing point of 20 ° C. or lower, and (2) an acrylic polymer surfactant and / or a vinyl polymer surfactant.

The epoxy resin recommended in the present invention is a colorless or light-colored transparent liquid epoxy resin among known epoxy resins. Typical examples are bisphenol type epoxy resins obtained from dihydric phenols such as bisphenol A and bisphenol F and epichlorohydrin, alicyclic epoxy resins, glycidyl ester type epoxy resins, novolac type epoxy resins, glycidyl ethers of long-chain polyols. Type epoxy resin, polyolefin type epoxy resin and the like, and they may be used alone or in combination of two or more kinds. Further, if necessary, a relatively low viscosity monoepoxide, polyepoxide or the like may be added as a reactive diluent. Further, flame retardation may be achieved by appropriately using halogenated polyepoxide.

The acid anhydride-based curing agent according to the present invention is not particularly limited as long as it can form an epoxy resin composition that is liquid at room temperature, but specifically, hexahydrophthalic anhydride, tetrahydrophthalic anhydride. Acid, phthalic anhydride, 3-
Methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, methylnadic acid anhydride, dodecenylsuccinic anhydride, decatriene such as α-terpinene and aloocimene Diels-Alder reaction product of carboxylic acid with maleic anhydride and hydrogenated products thereof,
Examples include structural isomers and geometric isomers as well as mixed modifications thereof, and saturated acid anhydrides are particularly preferable.

The amount of such an acid anhydride-based curing agent is not particularly limited as long as a predetermined curing can be obtained, but usually, the equivalent ratio of the acid anhydride group to the epoxy group is 0.7 to 1.2, It is preferably about 0.8 to 1.1. If the amount is more or less than this range, the cured properties such as glass transition temperature and moisture resistance tend to be remarkably lowered.

As the curing accelerator, conventionally known compounds, for example, tertiary amines such as benzyldimethylamine, tris (dimethylaminomethyl) phenol and dimethylcyclohexylamine; 2-ethyl-4-methylimidazole, 2-methylimidazole , 1-benzyl-2-methylimidazole and other imidazoles; 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter abbreviated as "DBU") and other diazabicycloalkenes, and their Salts, organic metal compounds such as zinc octylate, tin octylate and aluminum acetylacetone complex; quaternary ammonium compounds; organic phosphine compounds such as triphenylphosphine are fried and usually added to 100 parts by weight of the epoxy resin. It is used in an amount of about 01 to 10 parts by weight.

The saturated hydrocarbon (A) according to the present invention is a compound having a boiling point of 200 ° C or higher and a freezing point of 20 ° C or lower. When a saturated hydrocarbon whose boiling point is less than 200 ° C is used,
It is not practical because abrupt internal heat generation occurs during curing, and bubbles and voids are generated in the resulting cured product, and those with a freezing point above 20 ° C have poor miscibility with the epoxy resin composition and defoamability. Inferior to. As a suitable saturated hydrocarbon, n-paradecane such as n-dodecane, n-tetradecane, n-hexadecane, etc .; trade name IP Solvent 20
28, 2835 (manufactured by Idemitsu Petrochemical Co., Ltd.) and the like; trade name Daphne Oil KP-15, KP-
Liquid paraffins such as 32 (manufactured by Idemitsu Petrochemical Co., Ltd.), trade names Moresco White P-70, P-150, and P-350P (manufactured by Matsumura Petroleum Research Institute Co., Ltd.) are exemplified, and each of them is independent. Or in combination of two or more.

The amount of such a saturated hydrocarbon to be added is about 0.1 to 5 parts by weight, preferably 0.5 to 100 parts by weight of the epoxy resin.
It is about 3 parts by weight. If the amount is less than this range, bubbles are often entrained during stirring and mixing of the liquid composition to lower the defoaming property, and the effect of improving the moisture resistance becomes insufficient. On the other hand, if it exceeds the above range, the glass transition temperature of the cured product is lowered, which is not preferable.

Of the polymer surfactant (B) according to the present invention, the acrylic polymer surfactant is an oligomer having an acrylic compound such as (meth) acrylic acid ester as a main polymerization component, and specifically, Product name Disparon # 1970, L
-1982-50 (manufactured by Kusumoto Kasei Co., Ltd.) and the like.

The vinyl-based polymer surfactant is an oligomer having, for example, an alkyl (C ₃ -C ₁₈ ) vinyl ether as a main polymerization component, and specifically, trade name Disparlon #
1920, P-410 (manufactured by Kusumoto Kasei Co., Ltd.) and the like.

These polymeric surfactants are used alone or in combination of two or more, and the compounding amount thereof is 0.005 to 0.05 part by weight, preferably 0.01 part by weight with respect to 100 parts by weight of the epoxy resin. It is about 0.03 parts by weight. When the amount is less than this range, defoaming property is deteriorated because it becomes difficult to break, and when the amount is more than the range, turbidity tends to occur in the cured product, which is not preferable.

In the case of preparing a relatively large volume cast product by applying the epoxy resin composition containing the components (A) and (B), internal heat generation during heat curing may not be sufficiently suppressed. .

In this case, it has three or more alcoholic hydroxyl groups in the molecule, and the molecular weight per one alcoholic hydroxyl group (hereinafter referred to as "hydroxyl equivalent") is 200 or less, preferably 1
It is effective to add a polyhydric alcohol (C) of 20 or less in combination. When the hydroxyl equivalent is larger than 200 or when a monohydric or dihydric alcohol is used, the glass transition temperature of the cured product is remarkably lowered and the moisture resistance is lowered, which is not preferable.

Specific examples of suitable polyhydric alcohols include glycerin, polyglycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, or propylene oxide 3 of glycerin.
Examples thereof include alkylene oxide adducts of polyhydric alcohols such as mole adducts, trimethylolpropane ethylene oxide 9 mole adducts, and the like, and these may be used alone or in combination of two or more.

The compounding amount of such polyhydric alcohol is 100% epoxy resin.
It is preferably about 20 parts by weight or less based on parts by weight, and if it is more than 20 parts by weight, the glass transition temperature of the cured product tends to decrease and the moisture resistance tends to decrease, which is not desirable.

Saturated hydrocarbon (A), polymer surfactant (B) and polyhydric alcohol (C) may be used after premixing with epoxy resin or acid anhydride type curing agent and / or curing accelerator, respectively. However, they may be mixed all at once just before use.

In the epoxy resin composition according to the present invention, various additives such as an antioxidant, a dye, a pigment, a plasticizer, a release agent, a light diffusing material, and a filler, and a base material are adversely affected to the predetermined effects of the present invention. It can be appropriately blended within the range not exceeding.

The epoxy resin composition thus obtained is used for optical applications,
For example, optical equipment such as lenses and prisms, optical adhesives used for optical fibers, optical coating materials used for solar cell surfaces, light emitting elements such as light emitting diodes, light receiving elements such as photodiodes and phototransistors, and ultraviolet erasing type It is particularly useful as a sealing material for LSIs such as EP-ROMs and ICs.

[Examples] The present invention will be described in detail below with reference to Examples and Comparative Examples.

The properties of the epoxy resin composition obtained in each example were measured and evaluated by the following methods.

Defoaming Property 20 g of a predetermined epoxy resin composition, which was sufficiently stirred and mixed, was placed in a polypropylene beaker (φ60 mm) of 150 m, and decompressed at room temperature by reducing the pressure so that bubbles of the composition would not spill out of the beaker. The time from the start of defoaming until finally no bubbles are completely generated under a reduced pressure of about 10 mmHg (defoaming time) is measured.

Glass transition temperature (° C) A differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-30) of a sample obtained by curing the defoaming-treated epoxy resin composition under the condition of 100 ° C for 6 hours. ) Is used for measurement.

PCT Moisture resistance A cured product having a diameter of 75 mm and a thickness of 1.6 mm obtained by curing the defoaming-treated epoxy resin composition under the conditions of 100 ° C. for 6 hours is put in saturated steam of 121 ° C. and 2.2 atm. Upon exposure, the appearance change is observed, and the time until the test piece becomes cloudy is measured.

Appearance of cured product After defoaming the epoxy resin composition, a cured product (7 g [thickness 5 mm], 30 g [thickness 15 mm]) of different size is prepared under the condition of 100 ° C for 6 hours. Then, each appearance is visually judged.

Curing exothermic temperature (℃) 30g of defoamed epoxy resin composition φ50mm
The maximum exothermic temperature at the center of the cured product is measured when it is placed in an aluminum container and cured at 100 ° C.

Example 1 Bisphenol A diglycidyl ether (epoxy equivalent 188, hereinafter abbreviated as "DGEBA") as an epoxy resin, 4-methylhexahydrophthalic anhydride as an acid anhydride-based curing agent, and 2-ethyl- as a curing accelerator. 4-
Methylimidazole, "IP Solvent 2835" as saturated hydrocarbon (A) (boiling point: about 300 ° C, freezing point: -1)
(2 ° C. or less) and a predetermined amount of “Disparlon # 1920” as a polymer surfactant (B) were mixed to prepare an epoxy resin composition. Table 1 shows the defoaming time (minutes) of this product, the glass transition temperature (° C), the PCT moisture resistance (hours), the appearance and the curing exothermic temperature (° C) of the obtained cured product.

Examples 2 to 3 An epoxy resin composition was prepared by variously changing the acid anhydride type curing agent, the curing accelerator and the saturated hydrocarbon (A).
Table 1 shows various properties of the resin composition and a cured product obtained from the resin composition. The characteristics of the saturated hydrocarbon applied in each example are as follows.

N-Dedocaine boiling point = 216 ° C., freezing point = -10 ° C.-Molesco White P-150 boiling point = 300 ° C. or more, freezing point = -12 ° C. or less Example 4 Ethylene oxide 3 mol adduct of trimethylolpropane (hydroxyl equivalent = 90 or less "TMP / EO3 mol"
Is abbreviated. Table 1 shows various properties of the epoxy resin composition prepared by adding the above) and a cured product obtained therefrom.

Example 5 Various properties of an epoxy resin composition prepared by adding propylene oxide 9 mol adduct of pentaerythritol (hydroxyl equivalent = 165, hereinafter abbreviated as “PNT / PO 9 mol”) together and a cured product obtained therefrom. Is shown in Table 1.

Comparative Example 1 Table 1 shows various properties of an epoxy resin composition prepared without adding a saturated hydrocarbon (A) and a polymer surfactant (B) and a cured product obtained therefrom.

Comparative Example 2 Various characteristics of the epoxy resin composition prepared without blending the polymer surfactant (B) and the cured product obtained therefrom are described below.
Shown in the table.

Comparative Example 3 Table 1 shows various properties of the epoxy resin composition prepared without blending the saturated hydrocarbon (A) and the cured product obtained therefrom.

Comparative Example 4 n-decane (boiling point = 174 ° C, freezing point = -12 ° C or less)
Table 1 shows various properties of the epoxy resin composition prepared by blending and the obtained cured product.

Comparative Example 5 Propylene oxide 16 mol adduct of glycerin (hydroxyl equivalent = 333, hereinafter "glycerin / PO 16 mol")
Is abbreviated. Table 1 shows various properties of the epoxy resin composition prepared by blending) and the resulting cured product.

Comparative Example 6 Polypropylene glycol # 20 which is a dihydric alcohol
Table 1 shows the properties of the epoxy resin composition prepared by blending 0 (hydroxyl equivalent = 100, abbreviated as "PPG # 200" hereinafter) and the cured product obtained.

[Effects of the Invention] The epoxy resin composition according to the present invention has improved defoaming property (shortening the time required for defoaming operation), and further suppresses internal heat generation at the time of curing, thus increasing the amount of the curing accelerator. As a result, the curing time can be significantly shortened by selecting a high curing temperature, and as a result, the workability is significantly improved without deteriorating various properties such as the glass transition temperature, transparency, heat-resistant color stability and humidity resistance of the cured product. Can be improved.

Claims (2)

[Claims] 1. A composition which is liquid at room temperature and contains an epoxy resin, an acid anhydride-based curing agent and a curing accelerator, wherein (A) a saturated hydrocarbon having a boiling point of 200 ° C. or higher and a freezing point of 20 ° C. or lower; (B) An epoxy resin composition comprising an acrylic polymer surfactant and / or a vinyl polymer surfactant. 2. The epoxy resin composition according to claim 1, which further has 3 or more alcoholic hydroxyl groups in the molecule (C) and has a molecular weight of 2 per alcoholic hydroxyl group.
An epoxy resin composition comprising a polyhydric alcohol of 00 or less added.