JPH06145420A - Phenolic resin molding material - Google Patents

Abstract

PURPOSE:To provide a composition comprising a phenolic resin, hexamethylenetetramine microcapsules having a specific wall material and a filler, and excellent in thermal stability in a plasticized melted state in the cylinder of an injection molding machine on its injection molding and in curability in molds. CONSTITUTION:The objective composition comprises (A) a phenolic resin, (B) hexamethylenetetramine microcapsules having a wall material having a softening point of 10-150 deg.C (preferably polymethyl methacrylate and its copolymer), and (C) a filler, preferably in amounts of 100 pts.wt., 7-30 pts.wt. and 50-150 pts.wt., respectively. The component A is preferably an ordinary novolak phenolic resin. The component B is produced e.g. by dispersing fine powdery hexamethylenetetramine in a solution of polymethyl methacylate in ethylene dischloridecharging the dispersion in a large volume of water containing a dispersion stabilizer, evaporating the ethylene dichloride from the produced dispersion, and subsequently drying the residue.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol resin molding material excellent in molding processability and curability, and particularly in injection molding, the curing reaction hardly progresses in the cylinder of the injection molding machine, and The present invention provides a phenol resin molding material having extremely excellent molding processability that cures extremely quickly.

[0002]

2. Description of the Related Art Phenolic resin molding materials are excellent in heat resistance, electrical performance, mechanical performance and the like, and are therefore used in a wide range of applications such as automobile parts, electronic / electrical parts and mechanical parts. However, the conventional phenol resin molding material is 9
In the molten state plasticized to 0 to 125 ° C., the viscosity increases due to the progress of the curing reaction of the resin in the material.
It has the property of losing fluidity in minutes, and the thermal stability of the plasticized molten resin is extremely low. Therefore, when a conventional phenol resin molding material is injection-molded, there is a problem that the plasticization-melted molding material in the cylinder of the injection molding machine is significantly inferior in thermal stability and an appropriate molding condition range is extremely narrow. Conventionally, various methods such as increasing the fluidity of the molding material have been known as a method for solving this problem. However, if the thermal stability in the plasticized and molten state is improved, it is 150-
The curing reaction at 200 ° C. slows down, and conversely, when the curability in the mold is improved, the thermal stability becomes poor, and the thermal stability in the plasticized and molten state and the curability in the mold are reduced. It is difficult to obtain a phenol resin molding material in which both of the above are simultaneously improved.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides various kinds of phenol resin molding materials having excellent molding processability in which both thermal stability in a plasticized and molten state and curability in a mold are improved. The result of the study was that the purpose of the phenol is particularly excellent in the thermal stability in the plasticized molten state in the cylinder in injection molding, and the curability in the mold is extremely excellent. To provide a resin molding material.

[0004]

The present invention provides (a) a phenol resin, (b) hexamethylenetetramine microcapsules having a wall material having a softening point of 110 to 150 ° C., (c).
The present invention relates to a phenolic resin molding material containing a filler. The phenolic resin of the present invention is
A normal novolac type phenol resin obtained by the reaction of phenols and formaldehyde is used. As the phenols of the phenolic resin, one or more of monovalent and polyvalent phenols such as phenol, cresol, xylenol, naphthol, pt-butylphenol, bisphenol A, resorcin and their substitution products are used. It can be illustrated. Examples of the formaldehydes include formalin and paraformaldehyde. Further, as the phenol resin of the present invention, those modified with aromatic hydrocarbon resin, dimethoxyparaxylene, dicyclopentadiene and the like can be used.

The hexamethylenetetramine microcapsules having a wall material having a softening point of 110 to 150 ° C. according to the present invention are
Hexamethylenetetramine, which is strong at 110 ° C or lower, hardly dissolves in a phenol resin, softens at 110 to 150 ° C, and becomes fluid at higher temperatures, is hexamethylenetetramine, which is 0.5. One type or two or more types of spherical or flocked particles having a particle size of ˜30 μm can be used. As the wall material of the microcapsule, polystyrene, polycarbonate, ethyl cellulose, styrene butadiene copolymer, vinyl acetate ethylene copolymer, polyvinyl chloride, polyacrylic ester,
Polyamide etc. can be illustrated. The preferred wall material is polyacrylic acid ester, more preferably polymethylmethacrylate and its copolymer.

Such hexamethylenetetramine microcapsules are prepared, for example, by dissolving polymethylmethacrylate in ethylene dichloride, dispersing hexamethylenetetramine in fine powder form, and then dispersing this in a large amount of water containing a dispersion stabilizer. , Ethylene dichloride is evaporated under vacuum, followed by filtration and drying. In the present invention, the hexamethylenetetramine microcapsules are used by mixing 7 to 30 parts by weight with respect to 100 parts by weight of the phenol resin. If the content is 7 parts by weight or less, the curing of the resin will be insufficient, and if it is 30 parts by weight or more, the mechanical and electrical properties of the cured product will be deteriorated.

In the present invention, a phenol resin molding material having more excellent thermal stability and curability can be obtained by using a curing accelerator together. The curing accelerator is not particularly limited, and a usual curing accelerator can be used, such as magnesium oxide, calcium hydroxide,
Examples thereof include alkaline earth metal oxides or hydroxides such as barium hydroxide, and aromatic carboxylic acids such as salicylic acid and benzoic acid. These curing accelerators are used by appropriately blending them in a proportion of 0.5 to 20 parts by weight with respect to 100 parts by weight of the phenol resin. Examples of the filler of the present invention include wood powder, pulp powder, various pulverized products of woven fabric, organic products such as pulverized products of thermosetting resin laminates and molded products, silica, alumina, aluminum hydroxide, glass, talc, clay. Inorganic powders such as mica, calcium carbonate, and carbon, and inorganic fibers such as glass fiber, carbon fiber, and asbestos are used, and one or more of these can be used. These fillers are used by mixing 50 to 150 parts by weight with respect to 100 parts by weight of the phenol resin.

In the present invention, additives such as a flame retardant, a coloring agent and a release agent can be appropriately blended and used. In the present invention, if necessary, a phenol compound such as a resole type phenol resin, resorcin, bisphenol F or biphenol may be added to the phenol resin 100.
It can be used by appropriately mixing within 20 parts by weight with respect to parts by weight. The phenol resin molding material of the present invention contains various additives such as a phenol resin, microcapsules of hexamethylenetetramine, a filler and a curing accelerator, melt-kneaded with a roll mill, a twin-screw kneader, etc., cooled, and then ground. It can be manufactured by a usual method such as a method of manufacturing. During the manufacturing process of such a molding material, the hexamethylenetetramine microcapsules retain their shape without breaking the wall material.

[0009]

The function of the phenol resin molding material of the present invention is 90 to 1
It is remarkably excellent in thermal stability in a plasticized and melted state at 25 ° C., and is extremely excellent in curability in a mold at 150 to 200 ° C. The reason for this is that in the molding material in a plasticized molten state at 90 to 125 ° C., the wall material of the hexamethylenetetramine microcapsules shields the contact between the phenol resin and hexamethylenetetramine to prevent the progress of the curing reaction. However, at 150 to 200 ° C., the wall material melts and breaks, and the curing reaction proceeds.

[0010]

EXAMPLES The present invention will be described below with reference to examples. Here, "parts" represent parts by weight. [Example 1] 44 parts of a novolak resin (number average molecular weight 800) obtained by the reaction of phenol and formaldehyde, hexamethylenetetramine microcapsules using polymethylmethacrylate as a wall material (the proportion of the wall material is hexamethylenetetramine 70). 10 parts by weight, which is 30 parts by weight with respect to heavy parts, 3.5 parts of calcium hydroxide, 30 parts of wood flour,
10 parts of calcium carbonate and 2 parts of a release agent were mixed, melt-kneaded with a two-roll mill, cooled and pulverized to obtain a phenol resin molding material. [Example 2] Instead of the hexamethylenetetramine microcapsules of Example 1, hexamethylenetetramine microcapsules containing polystyrene as a wall material (the ratio of the wall material is 30 parts by weight with respect to 70 parts by weight of hexamethylenetetramine). Was obtained) and a phenol resin molding material was obtained in the same manner as in Example 1. [Comparative Example 1] 44 parts of novolac resin (number average molecular weight 800) obtained by the reaction of phenol and formaldehyde, 7 parts of hexamethylenetetramine powder, and 4 parts of calcium hydroxide.
Parts, 32 parts of wood powder, 11 parts of calcium carbonate, and 2 parts of a release agent were mixed, melt-kneaded with a two-roll mill, cooled and pulverized to obtain a phenol resin molding material.

Table 1 shows the material properties of the phenolic resins obtained in Examples 1 and 2 and Comparative Example 1.

[Table 1]

The thermal stability in Table 1 represents the thermal stability of the molding material in the plasticized and molten state, and was measured by the following method. 28 g of a powdery molding material is charged into a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) kept at 100 ° C., the rotor is rotated to plasticize and melt the molding material, and the torque of rotor rotation is measured. The torque increases as the viscosity increases with the progress of curing of the resin, and finally the fluidity is lost and the torque rapidly increases. The time from the start of measurement to the sudden rise in torque was measured, and this time was defined as thermal stability. The longer the time, the better the thermal stability. The curability in Table 1 represents the curing speed of the molding material in the mold, and a transfer molding machine having a cavity with a diameter of 50 mm and a thickness of 3 mm and having a mold kept at 175 ° C. was used for high frequency. 40g was prepared by charging 30g of tablet-shaped molding material that was preheated to 100-105 ° C with a preheater.
Molded for 2 seconds, taken out of the molded product, and the hardness of the molded product after 10 seconds was measured by a Barcol hardness tester No. It was measured at 935. The higher the hardness, the faster the curing speed and the better the curability.

From Table 1, the phenolic resin molding materials of the present invention shown in Examples 1 and 2 are excellent in thermal stability and curability as compared with the conventional phenolic resin molding material of Comparative Example 1. You can see that Moreover, Examples 1-2
And injection molding the phenolic resin molding material of Comparative Example 1,
When the molding machine was stopped in the middle and the molding material in the plasticized and molten state was allowed to stand in the cylinder as it was, after leaving all the materials of Examples 1 and 2 for 90 minutes, when the molding machine was restarted, Although molding was possible, the material of Comparative Example 1 hardened in the cylinder after being left for 30 minutes, and it was difficult to restart.

[0014]

As can be seen from the above examples, the phenol resin molding material of the present invention has extremely excellent thermal stability in the plasticized and molten state and curability at high temperature. For this reason,
Particularly in injection molding, the progress of the curing reaction of the plasticized molten resin in the cylinder of the injection molding machine is significantly suppressed, and it rapidly cures in the mold, so it can be applied to a wide range of molding conditions and has excellent molding processability. ing. Further, the phenol resin molding material of the present invention is extremely suitable for sprue / runnerless molding because it has extremely excellent thermal stability in a plasticized and molten state.

Claims (1)

[Claims] 1. A phenolic resin (a), a softening point 1 (b)
A phenol resin molding material comprising hexamethylenetetramine microcapsules having a wall material of 10 to 150 ° C., and (c) a filler.