JPH0689219B2 - Phenolic resin molding material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a phenolic resin molding material excellent in mechanical strength, particularly bending strength.

[Conventional technology]

Phenolic resin has been used in various fields since it has excellent heat resistance and physical properties, but it is widely used as a molding material in electric equipment parts, automobile parts, communication equipment parts, etc. There is.

In recent years, in order to promote the weight reduction and integration of various metal parts used in automobiles, switching to plastic has been actively studied, and in particular, mechanical strength, heat resistance, dimensional stability, etc. are required. Phenolic resin molding materials have come to be used for parts such as carburetor bodies, commutators, and oil pump impellers.

Conventionally, in order to satisfy the above characteristics, a phenol resin molding material mainly containing asbestos has been used. However, from the viewpoint of safety, asbestos use is strictly regulated, which makes it difficult to use. Therefore, a phenol resin molding material mainly composed of glass fiber, which can obtain high strength, has come to be used. Investigations are in progress, and an example thereof is disclosed in JP-A-61-151260. This publication discloses a phenol resin molding material which is mainly composed of glass fibers and to which a metal hydroxide is added.

[Problems to be Solved by the Invention]

The phenolic resin molding material in the publication has excellent properties, and a bending strength of 17.0 to 18.0 kg f / mm ² is obtained. The present inventors pay particular attention to this bending strength,
We obtained a large number of commercially available phenolic resin molding materials and measured their bending strength. The highest value was 20-23 kg f / m.
m ² of the material has been found. However, in reality, automobile manufacturers demand higher strength values than the above values in terms of safety.

The present invention has been made in view of the above problems, and an object thereof is to obtain a phenol resin molding material having higher bending strength (especially strength at the time of heating) than conventional products.

[Means for Solving the Problems]

The present inventors have conducted various studies in order to achieve the above-mentioned object, and in addition to phenolic resin and glass fiber, when glycerin is used at the time of compounding, at room temperature and at the time of heating, which is even better than conventional products, It was found that a molding material having bending strength can be obtained, and the present invention has been completed.

That is, the present invention relates to a phenol resin molding material containing 100 parts by weight of a phenolic resin, 40 to 300 parts by weight of glass fiber and 0.5 to 10 parts by weight of glycerin.

The phenolic resin used in the present invention is a novolac type phenol resin obtained by reacting phenols and aldehydes in the presence or absence of a catalyst, a resole (alkaline resole, ammonia resol) type phenol resin, a benzylic ether. Examples include unmodified phenolic resins such as type phenolic resins, and modified phenolic resins obtained by reacting or mixing with an optional modifying agent as needed during the production of these unmodified phenolic resins.
These resins can be used alone or in combination.

The glass fiber used in the present invention has a diameter of 6 to 20 μm,
One having a length of 1 to 10 mm is mentioned as a suitable one, and it can be used alone or in a mixture. The shape thereof may be a short fiber chip shape or the like. When these glass fibers treated with a silane coupling agent are used, good strength results can be obtained.

The glass fiber content is preferably 40 to 300 parts by weight, more preferably 50 to 250 parts by weight, based on 100 parts by weight of the phenolic resin. If the amount is less than 40 parts by weight, the desired bending strength cannot be obtained, the workability at the time of kneading exceeding 250 parts by weight is deteriorated, the efficiency of material production is lowered, the amount of phenolic resin is decreased, and the strength is also reversed. Tends to decline.

The amount of glycerin used in the present invention is preferably 0.5 to 10 parts by weight, more preferably 2 to 8 parts by weight, based on 100 parts by weight of the phenolic resin. If it is less than 0.5 part by weight, the bending strength is not improved, and if it exceeds 10 parts by weight, workability during kneading is deteriorated, which is not preferable.

The glycerin may be blended alone or may be dissolved in a solvent such as methanol or acetone before use. Regarding the blending time of the glycerin when mixing the raw materials,
Although not particularly limited, before blending the glass fiber treated with the silane coupling agent and the phenol resin and other additives, first, glycerin is blended first and the both are well mixed with the glass fiber, and the surface of the glass fiber Good results are obtained by adopting the method of coating glycerol with glycerin.

Phenolic resin molding material of the present invention, a curing agent, a curing accelerator, a coloring agent, a release agent, if necessary, in addition to the above-mentioned main raw materials.
Alternatively, additives such as a plasticizer can be blended.

The phenolic resin molding material of the present invention can be produced by a commonly used ordinary method, and the obtained molding material is molded by injection molding, transfer molding, and compression molding. You can

[Work]

Although the action of glycerin, which is an important raw material used for the phenolic resin molding material of the present invention, is not clear,
It is estimated as follows.

Glycerin has reactivity with silane coupling agents,
Also, since it has good compatibility with the phenolic resin, the sizing agent adhering to the glass fiber is removed by adding and mixing the glass fiber and glycerin, and the phenolic resin with the silane coupling agent intervening. It is thought that it plays a role of promoting the adhesive force between the glass fiber and the glass fiber. As a result, the mechanical strength of the phenolic resin molding material,
In particular, it is considered that the bending strength is significantly increased.

In addition, since it does not volatilize during manufacturing and can impart high fluidity to the molding material, it is considered that heat resistance is improved because a polymerized phenolic resin can be used.

〔Example〕

Next, the present invention will be described in more detail with reference to Examples.
The invention is not limited by these examples. In the examples and comparative examples, “part” means “part by weight”.

Example 1 Novolak type phenol resin (molecular weight 700) 40 parts Glass fiber (silane treated product, 6 μmφ, 3 mm) 60 parts Hexamethylenetetramine 6.4 parts Glycerin 0.8 parts Magnesium oxide 2.8 parts Slaked lime 1.2 parts Calcium stearate 1.2 parts Dye 1.0 part Above Among the respective raw materials, glass fiber and glycerin are first mixed in a mixer, then the other raw materials and a necessary amount of organic solvent are added and the mixing is further continued. The obtained mixture is sufficiently kneaded with a heated roll, and a sheet-shaped material is taken out and cooled. Next, the sheet material was crushed by a crusher to obtain a granular molding material. The spiral flow of the material was 460 mm.

Examples 2 to 3 Molding materials were obtained in the same manner as in Example 1 with the formulations shown in Table 1. The spiral flow of the material was 600 mm and 740 mm, respectively.

Comparative Example 1 Example 1 with a composition excluding glycerin shown in Table-1
A molding material was obtained in the same manner as in. The spiral flow of the material was 390 mm.

Bending pieces and impact pieces were formed using the molding materials obtained in Examples 1 to 3 and Comparative Example 1, and bending strength at room temperature and heat and Charpy impact strength were measured based on JIS K6911. The obtained results are as shown in Table-1.

The bending strength value during heating is a value measured at the temperature immediately after standing for 1 hour in each temperature atmosphere.

As can be seen from Table-1, the molding materials of the present invention obtained in Examples 1 to 3 are remarkably excellent in bending strength at room temperature and heat as compared with the comparative example material of the same class as the conventional product. . The Charpy impact strength also shows a slightly high value. Also, looking at the spiral flow of each material,
It can be seen that the material using glycerin has better fluidity.

〔The invention's effect〕

As explained above, the phenolic resin molding material of the present invention is excellent in bending strength by 30 to 50% at room temperature, especially when compared with the conventional product, and when heated, the rate of increase at room temperature is 200 ° C. or less, which is different from the room temperature. 90 to 120 at 250 ℃ and 300 ℃
% Is also an excellent material, and it is understood that it is a material suitable for the above-mentioned automobile parts and the like. In addition, since glycerin remains in the material without volatilizing, it is possible to obtain an effect that low-pressure molding can be performed as compared with the conventional product.

Claims (1)

[Claims] 1. A phenolic resin 100 parts by weight and a glass fiber 4
A phenol resin molding material containing 0 to 300 parts by weight and glycerin 0.5 to 10 parts by weight.