JPH0129204B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to vinyl ester resin compositions. Vinyl ester resin is a resin obtained by reacting an epoxy compound having two or more epoxy groups in the molecule with an unsaturated monobasic acid, and is also generally referred to as an epoxy ester resin. This resin has superior chemical resistance, mechanical properties, adhesive properties, and heat resistance compared to ordinary unsaturated polyester resins, so it is used in a wide range of fields including corrosion-resistant FRP and electrical insulation materials. . The vinyl ester resin in the present invention uses dihydrodicyclopentadienyl maleate, which is an adduct of dicyclopentadiene and maleic acid, as an unsaturated monobasic acid. This type of vinyl ester resin has the same features as mentioned above and is known from Japanese Patent Publication No. 14798/1983.
However, the vinyl ester resin shown therein is obtained by reacting carboxyl groups and epoxy groups in approximately equal amounts, and unfortunately has the drawback that its mechanical strength rapidly decreases in the high temperature range. The present invention has been made in view of the above circumstances, and its purpose is to provide a vinyl ester resin composition that has improved mechanical strength in a high temperature range without impairing its characteristics as a vinyl ester resin. It is in. In the present invention, the reason for using dihydrodicyclopentadienyl maleate as the unsaturated monobasic acid is as follows. In the present invention, first, an epoxy compound and an unsaturated monobasic acid are reacted, and the monobasic acid is bonded to the secondary hydroxyl group produced by this reaction by an esterification reaction. In order for this esterification reaction to proceed smoothly, it is necessary to carry out the reaction at a temperature of 150°C or higher while removing condensed water, but in the case of acrylic acid or methacrylic acid, which is commonly used as an unsaturated monobasic acid component Because double bonds are easily thermally polymerized, gelation occurs during the reaction. If the reaction temperature is lowered to prevent gelation, the esterification reaction will not proceed sufficiently and a large amount of acid components will remain in the system, leading to deterioration of properties.Additionally, if a large amount of polymerization inhibitor such as hydroquinone is used, the esterification reaction will not proceed sufficiently. Although esterification is possible, it is extremely disadvantageous industrially because a step of removing the polymerization inhibitor is required after the reaction. As a result of various studies, the present inventors found that an epoxy compound having two or more epoxy groups in the molecule and dicidorodicyclopentadienyl maleate were prepared with a carboxyl group/epoxy group ratio within the range of 1.2 to 2.0. The inventors have discovered that a vinyl ester resin composition obtained by dissolving a vinyl ester resin obtained by the reaction in a polymerizable monomer can satisfy the intended purpose, and have thus arrived at the present invention. The present invention is a vinyl ester obtained by reacting an epoxy compound having two or more epoxy groups in the molecule with dihydrodicyclopentadienyl maleate at a carboxyl group/epoxy group ratio of 1.2 to 2.0. The present invention relates to a vinyl ester resin composition containing a resin and a polymerizable monomer. Epoxy compounds having two or more epoxy groups in the molecule used in the present invention include bisphenol type epoxy resins obtained from bisphenol A, bisphenol F, etc. and epihalohydrin, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, etc. Glycidyl esters of polycarboxylic acids such as phthalic acid, adipic acid, sebacic acid, dodecanedioic acid, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-butanediol, 1,4-
Examples include glycidyl ethers of polyhydric alcohols such as butanediol, 1,6-hexanediol, and neopentyl glycol. The molecular weight of these epoxy compounds is preferably 174-1100. A molecular weight of 174 corresponds to diglycidyl ether of ethylene glycol, and there are practically no epoxy compounds with a molecular weight lower than that.
Furthermore, if the molecular weight exceeds 1100, the resulting vinyl ester resin will have fewer crosslinking reaction points, resulting in lower strength and higher viscosity, which is not preferred.
In addition, the molecular weight here refers to the value expressed by the product of the epoxy equivalent and the average number of epoxy groups. The dihydrodicyclopentadienyl maleate used in the present invention has the formula

It is a compound represented by the formula, and is
53-156998, patent application No. 157171, patent application No. 1983-
No. 5766, Japanese Patent Application No. 158240, US Patent No.
It is shown in the specification of No. 4264754. Dihydrodicyclopentadienyl maleate can be obtained, for example, by ring-opening esterification reaction of hydroxylated dicyclopentadiene and maleic anhydride. The carboxyl group/epoxy group ratio when reacting the above epoxy compound and dihydrodicyclopentadienyl maleate is limited to a range of 1.2 to 2.0. If this ratio is less than 1.2, the resulting vinyl ester resin will have low strength when heated, which is inappropriate. The reason for this is presumed to be that because the molecular weight of the vinyl ester resin produced is relatively large, the number of crosslinking points contained in a unit weight, ie, the density of crosslinking points, is low. On the other hand, when the ratio exceeds 2.0, carboxyl groups become stoichiometrically excessive,
This is unsuitable because dihydrodicyclopentadienyl maleate, which cannot react, remains in the system. Next, reaction conditions will be explained. It is well known that in unsaturated polyester resins using maleic acid or maleic anhydride as the unsaturated acid, if the fumarization rate is low, the performance of the cured product obtained is poor.
On the other hand, the unsaturated monobasic acid used in the present invention is dihydrodicyclopentadienyl maleate in terms of ease of reaction, yield, and prevention of gelation during vinyl esterification reaction when obtaining an unsaturated monobasic acid. limited to. For this reason, during the vinyl esterification reaction with an epoxy compound, it is preferable to promote fumarization by reacting at a temperature range of 170 to 230° C. for 2 hours or more until the reaction is completed. The vinyl ester resin composition in the present invention contains a polymerizable monomer, but from the viewpoint of performance and ease of handling, when the vinyl ester resin composition is 100 parts by weight, the vinyl ester resin is 45 to 80 parts by weight, It is preferable to use a vinyl ester resin composition containing 20 to 55 parts by weight of a polymerizable monomer.
If the vinyl ester resin is less than 45 parts by weight, the mechanical properties, heat resistance, etc. tend to deteriorate, and the inherent toughness of the vinyl ester resin is impaired, which is undesirable. If it exceeds 80 parts by weight, the viscosity of the vinyl ester resin composition This is not desirable because it increases the amount of water and makes handling difficult. For the same reason, the amount of the polymerizable monomer is also preferably within the above range. Examples of the polymerizable monomers used in the present invention include styrene monomers such as styrene, chlorostyrene, vinyltoluene, t-butylstyrene, and divinylbenzene, methyl methacrylate, butyl methacrylate, and β-hydroxy methacrylate. Ethyl, β-hydroxypropyl methacrylate, lauryl methacrylate, β-hydroxyethyl acrylate, ethyl acrylate and ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,
Polyhydric alcohols such as 4-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol, tris (β-hydroxyethyl) isocyanurate and esters of methacrylic acid or acrylic acid, vinyl acetate, Examples include diallyl phthalate and triallyl isocyanurate. A filler, a flame retardant, a reinforcing material, etc. may be added to the vinyl ester resin composition of the present invention, if necessary. Fillers include calcium carbonate, aluminum hydroxide, silica, talc, clay, silica sand, etc.; flame retardants include organic halides, phosphate esters, antimony trioxide, red phosphorus, aluminum hydroxide, molybdenum compounds, etc.; reinforcing materials; Examples include glass fiber, vinylon fiber, carbon fiber, asbestos, and wollastonite. Furthermore, the composition of the present invention contains cobalt naphthenate, manganese naphthenate, cobalt octenoate,
Curing accelerators such as N,N-dimethylaniline, peroxide curing agents such as methyl ethyl ketone peroxide, benzoyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyoctoate, benzophenone, benzoin isopropyl ether, etc. Although curing is performed using a photopolymerization initiator or the like, the curing agent and curing method are not limited at all. The present invention will be explained below with reference to Examples. In the following description, "parts" represent parts by weight. Example 1 A four-necked flask with a stirrer and a seal,
A reflux condenser, a thermometer, and a nitrogen inlet tube were attached, and 405 parts of hydroxylated dicyclopentadiene (Sidecanol, registered trademark of Hitachi Chemical Co., Ltd.) and 265 parts of maleic anhydride were added to this apparatus, and the mixture was heated at 120°C under a nitrogen stream for 30 minutes. After reacting for hours, dihydrodicyclopentadienyl maleate was obtained. Next, in this flask, 344 parts of Epicote 807 (bisphenol type epoxy resin manufactured by Yuka Ciel Japan Co., Ltd., epoxy equivalent: 172, number of epoxy groups: 2, molecular weight: 344), 4.1 parts of tetramethylammonium chloride, and hydroquinone were added.
0.20 part was added and reacted under a nitrogen stream at 150°C for 2 hours and then at 200°C for 3 hours to obtain vinyl ester resin R-1 with an acid value of 15.5. Add 40 parts of styrene to 60 parts of this resin, and then add benzoyl peroxide paste (NOF
JIS
Bending tests were carried out in accordance with K 6911. Bending strength is 960Kgf/cm ² at 23℃, 300Kgf/cm ² at 80℃, 110
It was 110 kgf/cm ² at ℃. Comparative Example 1 300 parts of hydroxylated dicyclopentadiene,
A vinyl ester resin Rf-1 having an acid value of 2.4 was obtained in the same manner as in Example 1 except that 196 parts of maleic anhydride was used. When a bending test was conducted in the same manner as in Example 1, the bending strength was 910Kgf/cm ² at 23℃ and 910Kgf/cm 2 at 80℃.
It was 95Kgf/cm ² and 25Kgf/cm ² at 110°C. Example 2 620 parts of dihydrodicyclohentadienyl maleate obtained in the same manner as in Example 1 and tetrahydrophthalic acid diglycidyl ester (epoxy equivalent: 176,
The number of epoxy groups is 2 (therefore, the molecular weight is 352), and 352 parts are heated to 150% in the presence of 4.9 parts of tetramethylammonium chloride and 0.19 parts of hydroquinone under a nitrogen stream.
℃ for 3 hours, then 190℃ for 4 hours, acid value
Vinyl ester resin R-2 with a weight of 28.5 was obtained. When this material was subjected to a bending test in the same manner as in Example 1, the bending strength was 1010Kgf/cm ² at 23℃ and 285Kgf/cm 2 at 80℃.
Kgf/cm ² and 55 Kgf/cm ² at 110°C. Comparative Example 2 Dihydrodicyclopentadienyl maleate
A vinyl ester resin Rf with an acid value of 8.6 was prepared in the same manner as in Example 2 using 496 parts of tetrahydrophthalic acid diglycidyl ester, 359 parts of tetrahydrophthalic acid diglycidyl ester, 1.7 parts of tetramethylammonium chloride, and 0.17 parts of hydroquinone.
-2 was obtained. When this material was subjected to a bending test in the same manner as in Example 1, the bending strength was 880 at 23°C.
Kgf/cm ² , 50Kgf/cm ² at 80℃, 9Kgf/cm 2 at 110℃
It was warm in ^cm2 . Example 3 Dihydrodicyclopentadienyl maleate
635 parts, 1,6-hexanediol diglycidyl ether (epoxy equivalent: 165, number of epoxy groups: 2,
Therefore, synthesis was carried out by a solvent method using 264 parts of molecular weight (330), 3.6 parts of tetramethylammonium chloride, 0.09 parts of hydroquinone, and 27 parts of toluene as an azeotropic solvent. The reaction was carried out at 150°C for 2 hours under a nitrogen stream, then at 200°C for 2 hours, and then at 180°C for 2 hours while recovering toluene to obtain vinyl ester resin R-3 having an acid value of 2.13. Add 30 parts of styrene and 10 parts of trimethylolpropane trimethacrylate to 60 parts of this resin,
Further, 2 parts of t-butyl peroxyoctoate (Percure O, manufactured by Nippon Oil & Fats Co., Ltd.) was added, and the test piece was cured at 80°C for 2 hours and then at 110°C for 2 hours, and a bending test was conducted using the test piece. Bending strength is 1180Kg at 23℃
f/cm ² , 340Kgf/cm ² at 80℃, 80Kgf/cm ² at 110℃
It was hot. Example 4 Using the same materials as in Example 1, under a nitrogen stream at 160 °C
The reaction was carried out at °C for 5 hours to obtain vinyl ester resin R-4 having an acid value of 21.5. A bending test was conducted on this in the same manner as in Example 1. Bending strength is 870 at 23℃
Kgf/cm ² , 220Kgf/cm ² at 80℃, 60Kgf/cm 2 at 110℃
It was warm in ^cm2 . Table 1 summarizes the carboxyl group/epoxy group ratio and bending test results of the vinyl ester resins obtained in Examples 1 to 4 and Comparative Examples 1 and 2 above.

[Table] As is clear from the above examples, the vinyl ester resin composition of the present invention can be used in the high temperature region of the cured product obtained by adjusting the ratio of carboxyl group/epoxy group within the above range. It is expected that the strength of FRP and electrical insulation materials will improve significantly.

Claims (1)

[Scope of Claims] 1. An epoxy compound having two or more epoxy groups in the molecule and dihydrodicyclopentadienyl maleate are mixed with a carboxyl group/epoxy group ratio.
A vinyl ester resin composition containing a vinyl ester resin and a polymerizable monomer, which are obtained by reacting within the range of 1.2 to 2.0. 2. The vinyl ester resin composition according to claim 1, which contains 45 to 80 parts by weight of vinyl ester resin and 55 to 20 parts by weight of polymerizable monomer. 3. The vinyl ester resin composition according to claim 1 or 2, wherein the epoxy compound has a molecular weight of 174 to 1100. 4. Claim 1, wherein the vinyl ester resin is a vinyl ester resin obtained by finally reacting an epoxy compound and dihydrodicyclopentadienyl maleate at 170 to 230°C for 2 hours or more.
The vinyl ester resin composition according to item 1, 2 or 3.