JPH0713177B2 - Phenol resin composition - Google Patents

Description

The present invention relates to a phenol resin composition used as a molding material or a varnish.

<Prior Art> Phenolic resins are used in a wide range of fields because they have excellent heat resistance, chemical resistance, solvent resistance, and excellent electrical and mechanical properties. However, since the phenol resin has a rigid molecular structure, it is brittle and has a low impact resistance.

As a method of improving such a defect, a method of simply blending a rubber component (Br.Polym.J 15 , 76 (1983)) and a method of chemically bonding the rubber component to a phenol resin (Japanese Patent Publication No.
43-27492), or a method of modifying a phenol resin with a drying oil (Japanese Patent Publication No. 45-20507).

<Problems to be Solved by the Invention> However, in the method of blending a rubber component with a phenol resin, only a specific rubber such as a nitrile rubber can be used because of the problem of compatibility between the rubber component and the phenol resin. Easy phase separation during heat curing. Since the rubber component is easily extracted by the solvent, there is a problem that the solvent resistance is poor.

Further, the method of chemically bonding the rubber component to the phenol resin or the method of modifying with a drying oil has a problem that the process is complicated and the cost is high.

The present invention has been made as a result of extensive studies in view of such circumstances, and it is an object of the present invention to provide a phenol resin composition having excellent solvent resistance and impact resistance and easy to produce.

<Means for Solving Problems> The present inventors have found that when a radical polymerization catalyst is added to a mixture of a rubber component having a carbon-carbon unsaturated double bond in the molecule and a phenol resin and the mixture is heated, the rubber component is The present invention has been found to form an IPN (Interpenetrating Polymer Network: interpenetrating network) structure with a phenolic resin, leading to the present invention.

That is, the gist of the present invention is a phenolic resin composition containing a polymerizable monomer that polymerizes to give a rubber-like elastic material, a phenolic resin, and a radical polymerization catalyst as essential components.

The radically polymerizable monomer used in the present invention is a combination of a polyfunctional monomer having two or more carbon-carbon unsaturated double bonds in the molecule and a monofunctional monomer having only one. Polyfunctional monomers are for forming cross-linking points,
Specifically, it is ethylene glycol diacrylate, ethylene glycol dimethacrylate, divinylbenzene, diallyphthalate, or the like.

The monofunctional monomer forms a main chain skeleton connecting the cross-linking points, and specifically, acrylic acid ester, methacrylic acid ester, styrene, acrylonitrile vinyl acetate and the like are used. These monomers may be used alone or in combination of two or more.

Next, the phenol resin used in the present invention is a novolac type or resol type phenol resin derived from various phenols and formaldehyde. These phenol resins may be modified with a drying oil, a xylene resin, a melamine resin, or the like.

In the case of novolac type phenol resin, polyamine such as hexamine, epoxy resin, isocyanate compound,
A curing agent such as a polyporaldehyde compound or a resole type phenol resin is further used in combination. The amount of free phenol in the phenol resin does not matter in the present invention.

Next, the radical polymerization catalyst is not particularly limited, but an azo polymerization catalyst is preferable, and specifically, 2,2'-azobisisobutyronitrile (AIBN), dimethyl-2,2'-azobisbutyrate , 1,1'-Azobis (1-cyclohexasancarbonitonyl), or 2,2'-azobis (2,4,4-
Trimethylpentane) or the like is used. These polymerization catalysts may be used alone or in combination of two or more.

The ratio of the monomer component to the phenol resin is in the range of 10 to 75% by weight of the monomer component. The ratio of monomer components
If it is less than 10% by weight, there is no modification effect, and if it exceeds 75% by weight, the curing of the phenol resin is delayed, which is not preferable.

The proportion of the polyfunctional monomer in the monomer component is preferably 0.5 to 80% by weight, more preferably 1 to 50% by weight.

When the phenolic resin is of the novolak type, the amount of curing agent normally used for curing it is further added.

Next, the radical polymerization catalyst is used in a proportion of 0.05 to 15% by weight, preferably 0.5 to 5% by weight, based on the above mixture. If the catalyst concentration is less than 0.05%, the crosslinking reaction will not proceed easily, and if it exceeds 15%, the reaction will proceed so vigorously that a homogeneous cured product cannot be obtained.

Blending components other than the above components in the composition according to the present invention is not limited at all and various fillers,
Additives such as antioxidants, curing accelerators, plasticizers, mold release agents, flame retardants, and coloring agents are free to be added.

A mixer having a stirrer, an ordinary kneader, or the like can be used as a device for mixing the above components.

When the mixture obtained as described above is heated, the polymerizable monomer undergoes cross-linking polymerization by the radical polymerization catalyst and is entangled with the chains of the phenol resin molecule, so-called interpenetrating polymer networks (hereinafter abbreviated as IPN). ) Form a structure.

A polymer mixed system having an IPN structure has been reported by, for example, Shibayama (Polymer Chemistry, 23, 24-29, 1966), but unlike conventional polymer blends and gloft polymers, two types of polymers The meshes penetrate each other,
It has a tangled structure.

In each polymer mixture system forming the IPN structure, at least one kind of polymer is crosslinked, but there is substantially no crosslinkage between different kinds of polymers. Therefore, a polymer mixed system with an IPN structure has a homogeneous structure without phase separation because the networks of the two polymers are entangled with each other as described above even when the component polymers are incompatible. A cured product having is obtained.

The identification method of the IPN structure can be confirmed by combining observation with an electron microscope, measurement of viscoelasticity / mechanical properties, measurement of solvent extraction, etc. Also, it was observed by measuring the tensile strength of the cured product.

<Examples> The present invention will be further described based on examples.

Examples 1 and 2 Resol type phenolic resin (formaldehyde / phenol molar ratio of 1.2 and reaction under an ammonia catalyst, gel time at 160 ° C. was 175 g having a gel time of 2.5 minutes, to 175 g of ethylene glycol diacrylate 30 g of 2-ethylhexyl acrylate. 45 g (Example 1) or 30 g of propylene glycol diacrylate, 45 g of n-butyl acrylate (Example 2) and 2.5 g of AIBN were placed in a flask and stirred and mixed at room temperature until they became homogeneous to obtain a pale yellow transparent liquid material. This liquid composition was filled in a mold and heated at 170 ° C. for 90 minutes to obtain a cured product, which was used in the test.

On the other hand, a blend obtained by excluding AIBN from Example 1 above was designated as Comparative Example 1. In addition, reference example 1 was prepared by curing only the above-mentioned phenol resin under the same conditions.

Table 1 shows the properties of the cured product.

Examples 3 to 4 175 g of novolac type phenol resin (synthesized with a hydrochloric acid catalyst with a formaldehyde / phenol molar ratio of 0.8 and having a softening point of 80 ° C.), 30 g of ethylene glycol diacrylate and 45 g of 2-ethylhexyl acrylate
(Example 3) or 30 g of propylene glycol diacrylate, 45 g of n-butyl acrylate (Example 4) and
A cured product was obtained in the same manner as in Examples 1 and 2 except that 2.5 g of AIBN and 25 g of hexamine were used.

Further, a blend obtained by excluding AIBN from Example 3 above was designated as Comparative Example 2, and 10 wt% of hexamine equivalent to the above phenol resin was further added and cured under the same conditions as Reference Example 2.

Table 1 shows the properties of the cured product.

As is clear from the results shown in Table 1, the cured product obtained from the phenol resin composition according to the present invention has a homogeneous structure and is excellent in solvent resistance and impact resistance.

<Effects of the Invention> As described in detail above, the phenol resin composition according to the present invention is a cured product having a structure in which the rubber component and the phenol resin are entangled with each other, so that the solvent resistance and impact resistance are improved. Since it is extremely easy to manufacture, it is excellent in economic efficiency and is useful as a molding material or a resin for laminated plates.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihisa Kumakura 1500 Ogawa, Shimodate, Ibaraki Shimodate Research Laboratory, Hitachi Chemical Co., Ltd. (72) Yukio Yoshimura 1500 Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Research Institute, Ltd. (56) Reference JP-A-59-71302 (JP, A)

Claims (3)

[Claims] 1. A monomer having radical polymerizability, a phenol resin and a radical polymerization catalyst, which are composed of a combination of a monomer containing two or more carbon-carbon unsaturated double bonds in the molecule and a monomer containing only one monomer. A phenol resin composition containing as a component. 2. The phenolic resin composition according to claim 1, wherein the phenolic resin is a resol type phenolic resin. 3. The phenol resin composition according to claim 1, wherein the phenol resin is a novolac type phenol resin.