JPH0912840A - Phenol resin molding material - Google Patents

Abstract

PURPOSE: To obtain a highly flame-retardant phenol resin molding material which exhibits a good mold flow, a low shrinkage, and an improved warpage or distortion. CONSTITUTION: This material contains as the essential ingredients a liq. resole type phenol resin as the binder, a novolak type phenol resin as the flowability- imparting agent, polyvinyl acetate as the shrinkage-reducing agent, and aluminum hydroxide as the flame retardant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid resol-type phenol resin molding material used for various molded articles such as building members, vehicle members and automobile members.

[0002]

2. Description of the Related Art In recent years, in response to the demand for weight reduction of building members, vehicle members, and automobile members, phenol resin molding materials using a phenol resin excellent in flame retardancy and low smoke generation as a binder have been developed. Research and development are actively conducted. As an example, in Japanese Patent Laid-Open No. 62-96556,
(a) Resol type phenolic resin, (b) hydroxide or oxide of alkaline earth metal, or silane compound, and (c)
Disclosed is a phenolic resin molding material characterized in that it comprises a mixture of fillers consisting of clay and talc or microspheres.

However, a drawback of the phenol resin molding material is a problem of dimensional stability such as warpage and deformation caused by a condensation reaction during heat and pressure molding. Therefore, lactones are used to improve the dimensional stability. As an example, in JP-A-63-291945, (a) a resole type phenolic resin, (b) a hydroxide or oxide of an alkaline earth metal, or a curing agent selected from the group of silane compounds,
A low-shrinkage phenolic resin molding material characterized by comprising (c) a filler and (d) a lactone is disclosed. Furthermore, with the recent demand for higher flame retardancy of materials, increasing the blending ratio of flame retardants and fillers, and the demand for low-temperature low-pressure molding conditions, conventional phenol resin molding materials have complicated shapes. In the case of, there was a problem that the fluidity in the mold at the time of molding was lowered, which impaired the appearance of the product.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the conventional phenolic resin molding materials, that is, the problems of poor fluidity in the mold at the time of heat and pressure molding, and further warpage and deformation. It is the result of various studies. Its purpose is to keep the fluidity in the mold during molding, workability, less warpage and deformation of the molded product after molding, excellent molding fluidity, low shrinkage, and high flame retardance. It is to provide a phenolic resin molding material.

[0005]

The essential components of the phenolic resin molding material of the present invention having excellent molding fluidity, low shrinkage and high flame retardancy are novolac type phenolic resin as a molding fluidity imparting agent, low Polyvinyl acetate as a shrinking agent and aluminum hydroxide as a flame retardant.

The compounding amount of the novolac type phenol resin used as the molding fluidity-imparting agent in the present invention is 2 to 3 relative to the non-volatile content of the liquid resol type phenol resin.
It is 0% by weight, preferably 5 to 20% by weight. The non-volatile content described here is JIS K 6833.
It is obtained by the method specified in. If the blending amount is less than 2% by weight, the effect of imparting molding fluidity cannot be sufficiently obtained.
If it exceeds 0% by weight, the curability will be impaired. The number average molecular weight of the novolac type phenol resin is 200 to 7
It is preferred to use one of 00. When the number average molecular weight is less than 200, the flame retardancy is impaired,
If the number average molecular weight exceeds 700, the viscosity when mixing the resin paste increases and the workability deteriorates. In addition, novolac-type phenol resin is an ortho-polymer when fast curing is required.
A type with many ortho bonds can also be used.

Further, the novolac type phenol resin is generally used by dissolving it in a solvent such as methanol, but hexamethylenetetramine is used as a curing agent in order to improve curability by 2 to 10% by weight based on the novolac type phenol resin.
Can be blended. Here, hexamethylenetetramine is previously supplied as a methanol solution with a novolak type phenolic resin, but in order to suppress chemical change over time,
It may be added in powder form when the resin paste is mixed.

Here, an example of obtaining a phenol resin molding material having low shrinkage and high flame retardancy is described in Japanese Patent Application No. 770085, but heating and pressing of a complex deep-drawing molded article is performed. There was a problem with the in-mold fluidity during molding. As a result of diligent studies to solve such a drawback, the appearance defect of the molded article could be improved by compounding the novolac type phenol resin as the fluidity-imparting agent. The main feature of the present invention is that the fluidity-imparting agent is added.

The compounding amount of polyvinyl acetate used as a low-shrinking agent in the present invention is 2 to 30% by weight, preferably 5 to 20% by weight based on the non-volatile content of the liquid resol type phenol resin. . If the blending amount is less than 2% by weight, the effect of low shrinkage cannot be sufficiently obtained, and if it exceeds 30% by weight, the flame retardancy is impaired. Further, it is preferable to use polyvinyl acetate having a polymerization degree of 600 or more. When the degree of polymerization is less than 600, it takes a long time to age the molding material. Regarding the end group, when comparing those having a partial carboxylic acid group at the end with those having no carboxylic acid group, both are effective in low shrinkage, but the one having a partial carboxylic acid group at the end group Is more effective.

The addition of polyvinyl acetate as a low-shrinking agent is already known in the case of unsaturated polyester resin molding compositions. On the other hand, in the case of a phenol resin molding material, an example can be found in JP-A-3-174465, but the flame retardancy is reduced as in the case of an unsaturated polyester resin molding material. Therefore, a phenol resin molding material having low shrinkage and high flame retardancy can be obtained only when used in combination with aluminum hydroxide.

The amount of aluminum hydroxide used as a flame retardant / filler in the present invention is 100 to 450% by weight based on the non-volatile content of the liquid resol type phenol resin. If the blending amount is less than 100% by weight, it is difficult to obtain good flame retardancy. If the blending amount exceeds 450% by weight, the viscosity of the resin paste at the time of manufacturing the molding material is too high and it is difficult to make it uniform, so that a smooth and sufficient strength is obtained. It becomes difficult to obtain a molded article having the same. Here, aluminum hydroxide also serves as a filler. As an example of blending aluminum hydroxide to obtain a nonflammable composite material, JP-A-50-3156, JP-A-50-3183, and JP-A-50-345.
1, JP-A-50-5471, JP-A-50-
26852, JP-A-58-149939,
Also, there are JP-A-3-189110 and the like, but in both cases, it was not possible to obtain a molded article that has both low shrinkage and high flame retardancy.

The liquid resol type phenolic resin which is the matrix used in the present invention is prepared by reacting phenols with an excess molar ratio of aldehydes in the presence of an alkaline catalyst. The molar ratio of aldehydes to phenols is usually 0.8-3.0,
It is preferably within the range of 1.1 to 2.5. As the alkaline catalyst, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, barium hydroxide or the like is used, but it is not particularly limited. The liquid resol type phenolic resin usually has a viscosity of 1 to 60 poise / 25.
° C, molecular weight (number average molecular weight) 140 to 400, pH 5 to
11, water content 1 to 30% by weight, and nonvolatile content according to JIS
The method specified in K 6833 is used in the range of 50 to 85% by weight.

The fillers used in the present invention include calcium carbonate, barium sulfate, talc, clay, silicon oxide, etc. in addition to the above-mentioned aluminum hydroxide, and they are used together with aluminum hydroxide. In the phenol resin molding material of the present invention, calcium hydroxide, magnesium oxide or the like is used as a curability adjuster, and generally used zinc stearate or the like is used as an internal release agent.

The fiber reinforcement used in the present invention is
It is glass fiber, carbon fiber, aramid fiber or the like, and the fiber length thereof is usually 1.5 to 51 mm. Especially when made into a sheet-shaped molding material, about 10-30m
m, about 1.5 to 15 mm when using bulk molding material
Is preferred. The amount of fiber reinforcement used is 5 to the total amount of molding material.
70% by weight.

In order to produce, for example, a sheet-shaped molding material using the molding material of the present invention thus obtained, a liquid resol-type phenol resin is a novolac-type phenol resin as a molding fluidity imparting agent, and a polycondensation agent as a low-shrinking agent. Vinyl acetate, flame retardant / aluminum hydroxide as a filler, a curability modifier, and an internal release agent are added and mixed to obtain a resin paste. Next, in the same manner as in the method for producing a general unsaturated polyester resin sheet-shaped molding material, fibers such as glass roving cut into a certain length by a sheet impregnating machine are sprinkled and impregnated with a resin paste to form a sheet. Roll up. The obtained sheet-like material is aged at room temperature to 50 ° C.
A molding material that is easy to handle is obtained by aging for 2 to 5 days and, if necessary, further aging.

To produce, for example, a bulk molding material using the molding material of the present invention, a conventional kneading device (eg, kneader, planetary mixer, etc.) is used, and a molding fluidity imparting agent is added to the liquid resol type phenol resin. As a novolac type phenolic resin, polyvinyl acetate as a low-shrinking agent, aluminum hydroxide as a flame retardant / filler, and if necessary a curability modifier, an internal release agent, etc. are mixed, and then a fiber reinforcement is added. Add, mix, and bag.

The phenol resin molding material thus obtained can be easily molded by pressurizing at high temperature to produce various molded articles used as building members, vehicle members, automobile members and the like. be able to.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments. The present invention is not limited by these examples. In addition, "part" and "%" described here
Unless otherwise specified, all are "parts by weight" and "% by weight".

<< Examples 1 to 5 >> Various phenolic resin sheet-shaped molding materials were prepared in the following manner to obtain molded products. First, liquid resol type phenolic resin (non-volatile content 7
5% by weight) at a ratio shown in Table 1 as a molding fluidity imparting agent, a novolac type phenol resin (number average molecular weight 40).
0), polyvinyl acetate as a low-shrinking agent, aluminum hydroxide, calcium carbonate, talc, clay as a flame retardant / filler, calcium hydroxide as a curability adjusting agent, and zinc stearate as an internal release agent. Then, if necessary, methanol for lowering the viscosity was added, and the mixture was mixed in a mixer for about 30 minutes until it became uniform to obtain a resin paste mixture. The weight ratio of the obtained resin paste mixture to the resin paste mixture was 7 by a sheet impregnation machine.
Glass fibers having a fiber length of 25 mm were dispersed while adjusting the ratio to 2:28, the resin paste mixture was impregnated into the glass fibers, and the two polymer films were molded into a sandwich type sheet. The film was aged at 45 ° C. for 3 days until it could be peeled off. Next, mold temperature 150 ℃,
After compressing for 15 seconds under a pressure of 100 kg / cm ² , degassing was performed once. Subsequently, compression molding was performed for 5 minutes at the same temperature and the same pressure to obtain a flat plate molded product of 30 × 30 × 3 mm.

Comparative Examples 1 to 3 Various phenolic resin sheet-shaped molding materials were prepared in the following manner to obtain molded products. First, liquid resol type phenolic resin (non-volatile content 7
5% by weight), in the proportions shown in Table 1, a novolac-type phenol resin as a molding fluidity imparting agent, polyvinyl acetate as a low-shrinking agent, aluminum hydroxide as a filler, talc,
Calcium hydroxide as a curability modifier, zinc stearate as an internal mold release agent, and, if necessary, methanol for making the viscosity low, and mixed with a mixer for about 30 minutes to prepare a resin paste mixture. Got Hereinafter, a flat plate molded product of 30 × 30 × 3 mm was obtained in the same manner as in the examples.

<Measurement and Evaluation Method of Molding Fluidity> Molding fluidity is obtained by cutting SMC into 22 cm squares and keeping the SMC weight W ₀ before molding constant. Next, under the conditions described in the example, 30 ×
A 30 × 3 mm flat plate molded product is obtained. Here, when the weight W _{1 of the} burr portion protruding from the 30 cm square is defined as (W ₁ / W ₀ ) × 100 (%). The obtained results are shown in Table 1, ○ (good) ~ △ ~
It was shown by x (bad). As is clear from these data, it was confirmed that the molding fluidity of the molded product to which the novolac type phenol resin was added was improved as compared with the molded product to which the novolac type phenol resin was not added.

<Measurement and Evaluation Method of Warp> Warp is JIS K
It measured according to 6911. Table 1 shows the obtained results. As is clear from these data, it was confirmed that the molded product to which the polyvinyl acetate was added had lower warpage and deformation, and improved low shrinkage, as compared with the molded product to which the polyvinyl acetate was not added.

<Evaluation Method of Flame Retardancy> The flame retardancy was measured according to the “Ministry of Transport Law” specified in Iron Transport No. 81 of the Ministry of Transport. Table 1 shows the obtained results. As is clear from these data, it was confirmed that the molded product to which aluminum hydroxide was added had improved flame retardancy as compared with the molded product to which aluminum hydroxide was not added.

[0024]

[Table 1]

[0025]

EFFECTS OF THE INVENTION According to the present invention, a phenol resin molding material having a low shrinkage property and a high flame retardance, in which molding fluidity defects, warpage, deformation, etc., which are defects of conventional phenol resin molding materials, are improved, is provided. can do.

Claims (6)

[Claims] 1. A molding material using a liquid resol-type phenol resin as a binder, wherein novolac-type phenol resin as a molding fluidity imparting agent, polyvinyl acetate as a low-shrinking agent, and aluminum hydroxide as a flame retardant are essential components. Phenolic resin molding material characterized by being mixed. 2. The phenol resin molding material according to claim 1, wherein the compounding amount of the novolac type phenol resin is 2 to 30% by weight based on the non-volatile content of the liquid resol type phenol resin. 3. The phenol resin molding material according to claim 1 or 2, wherein the novolac type phenol resin has a number average molecular weight of 200 to 700. 4. The phenol resin molding material according to claim 1, 2 or 3, wherein the blending amount of polyvinyl acetate is 2 to 30% by weight based on the nonvolatile content of the liquid resol type phenol resin. 5. The phenol resin molding material according to claim 1, wherein the average degree of polymerization of polyvinyl acetate is 600 or more. 6. The blending amount of aluminum hydroxide is 100 to 100 relative to the nonvolatile content of the liquid resol-type phenol resin.
The phenol resin molding material according to claim 1, which is 450% by weight.