JP2006265321A - Phenolic resin molding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phenolic resin molding material giving a molded article having excellent abrasion resistance while keeping original mechanical strengths. <P>SOLUTION: The phenolic resin molding material contains a phenolic resin and a high-molecular weight polyethylene having a viscosity-average molecular weight of ≥1,000,000. Preferably, the polyethylene has an average particle diameter of ≤150μm and the content of the polyethylene is 0.5-30 pts.wt. based on 100 pts.wt. of the phenolic resin. The material preferably further contains an inorganic filler having an average particle diameter of the primary particle of ≤500 nm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a phenol resin molding material.

  Conventionally, ceramics and metals are mainly used for mechanical parts such as automobiles and industrial equipment, but from the viewpoint of workability, high cost, and heavy solid weight, phenol resin molding containing glass fiber Alternatives to materials are drawing attention. However, the phenol resin molding material containing glass fiber has poor wear characteristics, and therefore it may be avoided to use it for parts that require wear resistance.

  For this reason, a technique for improving abrasion characteristics by blending polyethylene (for example, see Patent Document 1) is known. However, when the molecular weight of polyethylene is small, the heat resistance of polyethylene itself is inferior. In required parts applications (for example, compressor parts such as compressor pistons), it has been difficult to obtain sufficient wear resistance. On the other hand, a technique that can solve the above problem by blending high molecular weight polyethylene has been disclosed (for example, see Patent Document 2), but regarding the mechanical strength at the resin interface between the phenol resin and polyethylene. Further improvements are desired.

JP 2001-261828 A JP 2004-210837 A

  An object of the present invention is to provide a phenolic resin molding material capable of obtaining a molded article having more excellent wear resistance while maintaining the mechanical strength which is an originally required characteristic.

Such an object is achieved by the present invention described in the following (1) to (6).
(1) A phenol resin molding material containing a phenol resin and a high molecular weight polyethylene having a viscosity average molecular weight of 1,000,000 or more according to a solution viscosity method.
(2) The phenol resin molding material according to (1), wherein the high molecular weight polyethylene has an average particle size of 150 μm or less.
(3) The phenol resin molding material according to (1) or (2), wherein the content of the high molecular weight polyethylene is 0.5 to 30 parts by weight with respect to 100 parts by weight of the phenol resin.
(4) The phenol resin molding material according to any one of (1) to (3), further comprising an inorganic filler having an average primary particle diameter of 500 nm or less.
(5) The phenol resin molding material according to any one of (1) to (4), wherein the content of the inorganic filler is 0.5 to 30 parts by weight with respect to 100 parts by weight of the phenol resin.

(6) The phenol resin molding material according to any one of (1) to (5), wherein the inorganic filler is selected from silica, boehmite, and clay.

According to the present invention, a molded article having excellent wear resistance can be obtained without substantially impairing mechanical strength and dimensional stability, which are originally required characteristics.
Further, when the polymer contains a high molecular weight polyethylene having an average particle diameter of 150 μm or less and an inorganic filler having an average particle diameter of primary particles of 500 nm or less, the above characteristics can be further improved.

Hereinafter, the phenol resin molding material of the present invention (hereinafter simply referred to as “molding material”) will be described in detail.
The molding material of the present invention is characterized by containing a phenol resin and a high molecular weight polyethylene having a viscosity average molecular weight of 1,000,000 or more according to a solution viscosity method.

  Although it does not specifically limit as a phenol resin used for the molding material of this invention, A resol type phenol resin, a novolak type phenol resin, etc. are mentioned, These can be used individually or in combination. Among these, when considering heat resistance, a resol type phenol resin is often used, and a novolac type phenol resin is easy in that it is easy to select the resin viscosity and curability as appropriate and the material can be designed at low cost. Is often used.

When the resol type phenol resin is used, the type thereof is not particularly limited, and examples thereof include a methylol type resol phenol resin and a dimethylene ether type resol phenol resin.
In addition, the novolac type phenol resin is not particularly limited, but usually, phenols and aldehydes are combined with aldehydes against phenols (P) in the presence of an acidic catalyst such as oxalic acid, hydrochloric acid, sulfuric acid, toluenesulfonic acid ( F) can be obtained by reacting at a molar ratio (F / P) of 0.5 to 0.9.

  Although it does not specifically limit as phenols used here, For example, phenols, such as phenol, orthocresol, metacresol, paracresol, xylenol, para tertiary butylphenol, paraoctylphenol, paraphenylphenol, bisphenol A, bisphenol F, resorcinol Usually, phenol and cresol are often used.

Similarly, aldehydes are not particularly limited. For example, aldehydes such as formaldehyde, acetaldehyde, butyraldehyde, acrolein, or a mixture thereof, and substances that generate these aldehydes or these aldehydes. In general, formaldehyde is often used.
The form of the phenol resin is not particularly limited, and any form of liquid, solid, or powder can be used.

The molding material of the present invention contains high-molecular-weight polyethylene (hereinafter sometimes simply referred to as “polyethylene”) having a viscosity average molecular weight of 1,000,000 or more according to the solution viscosity method. By making the molecular weight of polyethylene more than the said lower limit, the abrasion resistance of the molded product obtained can be improved dramatically. When the molecular weight of the polyethylene is below the lower limit, melt wear occurs due to the poor heat resistance of the polyethylene itself, and the resulting molded product cannot obtain a sufficient wear resistance improvement effect under high load. Sometimes.
For such purposes, the molecular weight of polyethylene is particularly preferably 1 million to 5 million. When the molecular weight of polyethylene exceeds the above upper limit, the elastic modulus of polyethylene itself tends to be too high. By setting the molecular weight of polyethylene within the above range, impact strength and toughness can be combined, and the balance between mechanical strength and wear resistance can be improved.

In the molding material of the present invention, the polyethylene is preferably used in the form of particles.
The average particle diameter of polyethylene is not particularly limited, but is preferably 150 μm or less. More preferably, it is 50 micrometers or less, Most preferably, it is 30 micrometers or less.
By setting the average particle diameter of polyethylene to the upper limit value or less, the wear resistance can be improved without reducing the mechanical strength. When the average particle diameter exceeds the upper limit, the wear resistance is improved, but the mechanical strength may be lowered or the molded appearance may be lowered. This is because the inherent compatibility between polyethylene and phenolic resin is low, and if the average particle size of polyethylene is increased more than necessary, the interface between the phenolic resin and polyethylene is likely to be the starting point of fracture, resulting in a decrease in mechanical strength. In addition, it is thought that the molded appearance is impaired because it tends to bleed out.
In addition, the lower limit of the average particle diameter of the polyethylene is not particularly limited, but is preferably 10 μm or more from the viewpoints of handleability and availability.

Next, content of a phenol resin and polyethylene is demonstrated.
Although it does not specifically limit in the molding material of this invention, It is preferable to contain 0.5-30 weight part of polyethylene with respect to 100 weight part of phenol resins (when it uses hexamethylenetetramine). . More preferably, it is 1-20 weight part, Most preferably, it is 2-10 weight part. By setting the polyethylene content within such a range, the wear resistance and the mechanical strength can be improved.
When the polyethylene content is below the lower limit, sufficient lubricity cannot be imparted to the surface of the molded product, and it may be difficult to obtain sufficient wear resistance. This is probably because the amount of polyethylene is relatively small compared to other materials such as resin and glass fiber, and its volume is insufficient to provide sufficient lubricity on the surface of the molded product. .
On the other hand, when the polyethylene content exceeds the upper limit, the mechanical strength, dimensional stability, and molded appearance of the molded product may be impaired. This is thought to be due to an increase in the volume of polyethylene, an increase in the interface between the resin and polyethylene, which can be the starting point of fracture due to stress, and an increase in the amount of bleed out during molding. Also, if the polyethylene content is excessive, the heat resistance of the molded product is inferior, and the amount of wear associated with the melt wear of polyethylene may increase, which may have an adverse effect on the wear resistance. It is necessary to select the content appropriately according to the use environment of the product.

The molding material of the present invention preferably contains an inorganic filler having an average primary particle diameter of 500 nm or less (hereinafter sometimes referred to as “fine inorganic filler”) in addition to the above-described polyethylene. By containing the fine inorganic filler, the mechanical strength can be improved and the wear resistance can be further improved.
The average particle size of the fine inorganic filler is more preferably 100 nm or less, and particularly preferably 50 nm or less. By setting the average particle diameter of the fine inorganic filler within such a range, the mechanical strength can be further improved. This is presumed to be because the smaller the average particle size of the fine inorganic filler contained, the more the molded product is reinforced in a minute matrix unit.
In addition, since the surface hardness of the molded product is increased, the surface of the molded product is hardly scraped. Therefore, when polyethylene and the above-mentioned fine inorganic filler are contained in combination, the surface of the molded product has lubricity and the resin is difficult to be scraped, so that it is presumed that the wear resistance is further improved.
In addition, the lower limit of the average particle diameter of the primary particles in the fine inorganic filler is not particularly limited, but is preferably 10 nm or more from the viewpoints of handleability and availability.

  The fine inorganic filler used in the molding material of the present invention is not particularly limited, and examples thereof include calcium carbonate, clay, talc, wollastonite, silica, glass beads, boehmite, glass powder, metals, rare earths and sub-metals. Examples thereof include oxides and hydroxides, and fillers having high Mohs hardness such as silica and zirconium oxide are preferable in terms of increasing the hardness of the surface of the molded article and making it difficult to wear. However, if the Mohs hardness is higher than necessary, the self-abrasion property is low, but the aggressiveness to the counterpart material may be high. Therefore, it is necessary to select appropriately according to the counterpart material and the use environment. Among these, silica is particularly preferable because it is inexpensive and easily available. On the other hand, clay is preferable in terms of excellent heat resistance and chemical resistance of the molded product. This is because the clay in the form of a minute plate is oriented innumerably on the surface of the molded product, so that oxygen and chemicals inside the molded product are Presumed to prevent intrusion and suppress deterioration. Further, although the mechanism is not clear, boehmite is preferable in that an effect of improving mechanical strength is easily obtained.

The content of the fine inorganic filler used in the molding material of the present invention is not particularly limited, but is 0.5 to 30 with respect to 100 parts by weight of phenol resin (including hexamethylenetetramine when used). It is preferable that it is a weight part. More preferably, it is 1-20 weight part, Most preferably, it is 2-15 weight part. By setting the content of the fine inorganic filler in such a range, it is possible to provide a molding material capable of improving mechanical strength and wear resistance and reducing cost.
If the content of the fine inorganic filler is below the above lower limit, the fine inorganic filler volume is insufficient, the reinforcement by the fine matrix is weak, and sufficient effects of improving mechanical strength and wear resistance are obtained. There may not be. On the other hand, even if the content of the fine inorganic filler exceeds the above upper limit, the effect of further improving the mechanical strength and wear resistance is low and the cost is high. Must be selected.

  In addition to the raw materials described so far, the molding material of the present invention includes inorganic fillers other than those described above, such as glass fibers and powdered inorganic fillers, as long as the objects and effects of the present invention are not adversely affected. In addition to the filler, those generally used as a molding material such as a plasticizer and a release agent can be used.

  The molding material of this invention can be manufactured by a normal method. That is, it contains a predetermined amount of the above raw materials, premixed using a ribbon blender, planetary mixer, etc., and then melt-kneaded using a heating roll or a twin-screw kneader and further granulated or cooled and pulverized -It can be used as a molding material through operations such as classification.

The molding material of the present invention can be molded by a normal molding method. For example, it can be molded into a predetermined molded product shape by compression molding, transfer molding, injection molding or injection compression molding.
As an example of injection molding, cylinder temperature 60-110 ° C., injection pressure 50-200 MPa, injection speed 1-20 mm / sec, mold temperature 150-200 ° C., curing time 15-120 seconds, mold clamping pressure 50-400. However, the above molding conditions are appropriately selected according to the melt viscosity of the phenol resin used, the type and content of the curing agent, the release agent, and the size of the molded product. .

  A molded product formed by molding the molding material of the present invention has high mechanical strength and excellent wear resistance. For example, excellent wear resistance is required even under a high load. It is suitably used for a compressor component such as a compressor piston.

  Hereinafter, the present invention will be described by way of examples.

1. Production of molding material (1) Example 1
Novolak-type phenolic resin 40.0% by weight, hexamethylenetetramine 8.0% by weight, glass fiber 45% by weight, polyethylene resin powder (A) 2.5% by weight, colloidal silica (solid content) 2.5 wt%, magnesium oxide 1.0 wt% as a curing catalyst, and 1.0 wt% stearic acid as a release agent were premixed for 3 minutes using a Henschel mixer.
The obtained mixture was melt-kneaded for 3 minutes with a heating roll at 90 ° C., cooled in a sheet form, and pulverized to obtain a granular molding material.

(2) Example 2
A molding material was obtained in the same manner as in Example 1 except that boehmite was blended instead of colloidal silica.

(3) Example 3
A molding material was obtained in the same manner as in Example 1 except that the glass fiber was reduced to 42.5% by weight and the colloidal silica was increased to 5% by weight.

(4) Example 4
A molding material was obtained in the same manner as in Example 2 except that the glass fiber was reduced to 38.5% by weight and the boehmite was increased to 9% by weight.

(5) Example 5
The molding material was obtained in the same manner as in Example 1 except that the glass fiber was increased to 45.5% by weight, the polyethylene resin powder (A) was increased to 4.5% by weight, and no colloidal silica was added. It was.

(6) Example 6
A molding material was obtained in the same manner as in Example 1 except that the polyethylene resin powder (B) was blended in place of the polyethylene resin powder (A).

(7) Comparative Example 1
40.0% by weight of novolak-type phenolic resin, 8.0% by weight of hexamethylenetetramine, 50% by weight of glass fiber, 1.0% by weight of magnesium oxide as a curing catalyst, and stearic acid as a release agent 1.0% by weight was premixed for 3 minutes using a Henschel mixer.
The obtained mixture was melt-kneaded for 3 minutes with a heating roll at 90 ° C., cooled in a sheet form, and pulverized to obtain a granular molding material.

(6) Comparative Example 2
A molding material was obtained in the same manner as in Example 5 except that the polyethylene resin powder (C) was used instead of the polyethylene resin powder (A).

(7) Comparative Example 3
A molding material was obtained in the same manner as in Example 5 except that the polyethylene resin powder (D) was used instead of the polyethylene resin powder (A).

  The blending of the molding materials obtained in Examples and Comparative Examples, and the characteristics of molded products using these molding materials were evaluated. The results are shown in Table 1.

3. Notes to the table [Materials used]
(1) Novolac type phenolic resin: A-1082 manufactured by Sumitomo Bakelite Co., Ltd.
(2) Hexamethylenetetramine: Mitsubishi Gas Chemical Co., Ltd. Hexamine (3) Glass fiber: Nippon Sheet Glass Co., Ltd. Chopped strand RES (fiber length 1 to 4 mm, fiber diameter 10 to 13 μm)
(4) Polyethylene resin powder (A): Miteron (viscosity average molecular weight 1.3 million, average particle diameter 25 μm) manufactured by Mitsui Chemicals, Inc.
(5) Polyethylene resin powder (B): Hi-Zex (viscosity average molecular weight 1.3 million, average particle diameter 150 μm) manufactured by Mitsui Chemicals, Inc.
(6) Polyethylene resin powder (C): Fluxen UF20 manufactured by Sumitomo Seika Co., Ltd. (viscosity average molecular weight 40,000, average particle diameter 25 μm)
(7) Polyethylene resin powder (D): Sunwax LEL-250P (viscosity average molecular weight 3000, average particle diameter 75 μm) manufactured by Sanyo Chemical Industries
(8) Colloidal silica: PL-3 (average particle diameter of primary particles: 35 nm) manufactured by Fuso Chemical Industry Co., Ltd.
(9) Boehmite: CAM9010 manufactured by Sakai Kogyo Co., Ltd. (average particle diameter of primary particles: 15 nm)
(10) Magnesium oxide: Kyowa Mug 30 manufactured by Kyowa Chemical Co., Ltd.
(11) Stearic acid: Lunac S40 manufactured by Kao Corporation

[Evaluation of molded products]
The molding materials obtained in the examples and comparative examples were transferred and molded at a mold temperature of 175 ° C. and a curing time of 3 minutes to prepare test pieces.

(1) Abrasion resistance (conforms to JIS K 7218)
A wear test was performed under the following conditions using a thrust friction and wear tester, and the amount of wear and the dynamic friction coefficient of the test piece were measured. The test conditions are as follows.
Test pressure: 4.9 MPa
Sliding speed: 0.2m / sec
Test environment: normal temperature, in dry atmosphere Test time: 4 hr

(2) Bending strength, flexural modulus, compressive strength (normal temperature and 120 ° C when heated)
Measured according to JIS K 6911 “General Thermosetting Plastics Test Method”.

(1) Compressive strength The opening of the molded product was placed downward, and the breaking load when compressed was measured.

(2) Abrasion resistance As shown in FIG. 1b, a 10 mm square × 3 mm thick test piece was cut out from the side of the molded product, and the dynamic friction coefficient was measured with a thrust type frictional wear tester.

From the result of Table 1, Examples 1-6 are the molding materials of this invention containing the high molecular weight polyethylene whose viscosity average molecular weight is 1 million or more, and the fine inorganic filler whose average particle diameter of a primary particle is 500 nm or less. In addition, the wear amount and the dynamic friction coefficient of the obtained molded product were both low, and the wear resistance was good. Also, the mechanical properties were good.
Particularly in Examples 1 to 3, since the blending amount of the high molecular weight polyethylene, the blending amount of the fine inorganic filler, and the average particle diameter of the high molecular weight polyethylene used were optimal, the wear resistance and the mechanical strength were particularly excellent. It became a thing.
On the other hand, Comparative Example 1 does not contain high-molecular-weight polyethylene having a viscosity average molecular weight of 1,000,000 or more, so that the resin wear amount and the dynamic friction coefficient are high and the wear resistance is poor.
In Comparative Example 2 and Comparative Example 3, since low molecular weight polyethylene is contained, the abrasion resistance is better than that of Comparative Example 1, but since the molecular weight is small, the effect is slight, and in particular heat The mechanical strength was low and the heat resistance was poor.

The present invention is a phenol resin molding material containing a phenol resin and a high molecular weight polyethylene having a viscosity average molecular weight of 1,000,000 or more as essential components, and a molded article having excellent wear resistance without impairing mechanical strength. Obtainable. In addition, since the molding material contains a fine inorganic filler having an average primary particle diameter of 500 nm or less, these characteristics can be further improved, for example, a compressor component such as a compressor piston, etc. It can be suitably used for mechanical parts used at high loads.

Claims (6)

A phenol resin molding material comprising a phenol resin and high molecular weight polyethylene having a viscosity average molecular weight of 1,000,000 or more according to a solution viscosity method. The phenol resin molding material according to claim 1, wherein the high molecular weight polyethylene has an average particle size of 150 μm or less. The phenol resin molding material according to claim 1 or 2, wherein a content of the high molecular weight polyethylene is 0.5 to 30 parts by weight with respect to 100 parts by weight of the phenol resin. Furthermore, the phenol resin molding material in any one of Claim 1 thru | or 3 which contains the inorganic filler whose average particle diameter of a primary particle is 500 nm or less. The phenol resin molding material according to any one of claims 1 to 4, wherein a content of the inorganic filler is 0.5 to 30 parts by weight with respect to 100 parts by weight of the phenol resin.
The phenol resin molding material according to any one of claims 1 to 5, wherein the inorganic filler is selected from silica, boehmite, and clay.