JP4062286B2 - Phenolic resin molding materials and molded products - Google Patents

Description

  The present invention relates to a molded product used as a heat-resistant component and a phenol resin molding material for producing the molded product. In particular, the present invention relates to a heat-resistant component such as a motor commutator used for an electrical component mounted around the engine portion of an automobile. The present invention relates to a phenol resin molding material suitably used for forming.

  Conventionally, phenol resin molding materials are excellent in heat resistance, dimensional stability, and moldability, and have a track record of being used for motor electrical commutators for automobiles and surrounding structural parts (for example, see Patent Document 1). Recently, from the viewpoint of global environmental protection, etc., each unit has been electrified for the purpose of reducing the fuel consumption of automobiles, and the demand for motors has increased due to the change from hydraulic control to motorized motorization. There is a need for improvements in quality.

  In particular, in terms of motor quality, there is a need to respond to the need for noise reduction in automobiles to pursue comfort in the vehicle environment. Since the commutator is a sliding part, its dimensional accuracy has a great influence on motor noise. Therefore, the molding material used to form the commutator used in the motor is the dynamics during and after parts processing. There is a demand for materials that have little dimensional change due to mechanical load and thermal history.

However, molded products made from conventional phenolic resin molding materials satisfy the required quality in terms of motor characteristics, but there is a problem of large dimensional changes due to mechanical loads and thermal history during parts processing and after processing. There was a case where the noise generated when the motor was driven became louder.
JP-A-6-345853

  The present invention has been made in view of the above points, and provides a phenolic resin molding material capable of forming a molded product with a small dimensional change due to mechanical load and thermal history during and after parts processing. It is the purpose. It is another object of the present invention to provide a molded product having a small dimensional change due to mechanical load and thermal history during and after parts processing.

The phenolic resin molding material of the present invention is a phenolic resin molding material in which a filler is blended with a phenolic resin, and the filler is a structure of the following formula (1) or (2) and m is an integer of 1 to 10 Using alkyl ester-based material or methacrylic acid alkyl ester-based material , phenol resin content is 25-35 mass%, filler content is 0.5-10 mass%, SBR or NBR content is 0.1 -5 mass%, the compounding quantity of glass fiber is 40-65 mass%, and the compounding quantity of an inorganic mineral is 1-15 mass% , It is characterized by the above-mentioned.

  In the present invention, the filler preferably has a graft layer on the surface.

In the present invention, the graft layer is preferably any one of an acrylonitrile / styrene copolymer, a methacrylic acid alkyl ester / styrene copolymer, and a methacrylic acid alkyl ester polymer .

  Moreover, it is preferable that this invention is 0.5-10 mass% of compounding quantities of a filler.

  The molded article of the present invention is characterized by being formed by molding the above-mentioned phenol resin molding material by a hot press.

  According to the present invention, it is possible to suppress the shrinkage of the phenol resin after curing by the elastic filler during the annealing process performed after molding, and at the same time, it can be expanded even in a hot atmosphere environment. It becomes possible to suppress the dimensional change of the molded product, and this stress relaxation action can reduce the dimensional change due to the mechanical load and the thermal history during parts processing from the molded product and after the processing.

  In addition, the graft layer on the surface of the filler can increase the dispersibility of the filler in the molding material, and can increase the effect of reducing the dimensional change of the molded product by the filler.

In addition, when the graft layer is a polymer of acrylonitrile / styrene copolymer, alkyl methacrylate ester / styrene copolymer, or alkyl methacrylate ester , the impact resistance and wear of the filler can be increased. Is.

  Moreover, when the compounding quantity of a filler shall be 0.5-10 mass%, it will become easy to relieve the stress concerning a molded article with a filler.

Moreover, the compounding quantity of a phenol resin is 25-35 mass%, the compounding quantity of a filler is 0.5-10 mass%, the compounding quantity of SBR or NBR is 0.1-5 mass%, and the compounding quantity of glass fiber is 40. When the blending amount of the inorganic mineral is 1 to 15% by mass, the performance as a motor commutator can be easily obtained.

  Further, by molding the phenol resin molding material with a hot press, it is possible to obtain a molded product with a small dimensional change due to a mechanical load and a thermal history during and after processing the part.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The phenol resin used in the present invention is not particularly limited, and a novolac type phenol resin and a resol type phenol resin can be used alone or in combination. In addition, it is preferable to use a phenol resin having a weight average molecular weight of 2000 to 4000.

The filler used in the present invention is formed using an acrylic acid alkyl ester material or a methacrylic acid alkyl ester material having the structure shown in (1) or (2) above, and has elasticity. . The carbon number m of the structure shown in the above (1) or (2) is an integer of 1 to 10. If m is less than 1, there may be a problem that a sufficient effect of suppressing the dimensional change cannot be obtained. If m is larger than 10, the dispersibility with respect to the phenol resin is deteriorated and the appearance of the molded product is deteriorated. The problem of becoming may occur. Further, the (1) or (2) the number of repetitions n of the structure shown in is not particularly limited, the actual molecular weight is considered to be about 10,000 to 300,000, n is estimated to be 100 to 30 0. The filler of the present invention can be formed of an acrylic acid alkyl ester material or a methacrylic acid alkyl ester material having only the structure shown in the above (1) or (2). A copolymer of the structure shown in 2) with ethylene, acrylonitrile rubber, dimethylsiloxane, or the like can be formed as an alkyl acrylate ester material or an alkyl methacrylate ester material. In addition, when formed with an acrylic acid alkyl ester material or a methacrylic acid alkyl ester material having only the structure shown in (1) or (2), the terminal of the structure shown in (1) or (2) is hydrogen. (H).

The filler of the present invention is a substantially spherical granular material having an average particle diameter of 2 μm to 1 mm. Moreover, as a filler of this invention, what provided the graft layer on the surface can be used. This filler is formed by covering the entire surface of the core portion with a graft layer. In this case, the core portion can be formed of the above-mentioned alkyl acrylate ester material or alkyl methacrylate ester material, and the graft layer is an acrylonitrile / styrene copolymer, methacrylic acid alkyl ester / styrene copolymer, methacrylic acid. It can be formed of any alkyl ester polymer . A polymer of methacrylic acid alkyl ester used in the graft layer has the same structure as the above (2) as the core part.

In the present invention, in addition to the phenol resin and filler, SBR or NBR , glass fiber, inorganic mineral, curing agent, lubricant, dye, and the like can be blended as required. In particular, a phenol resin molding material for a commutator is used. When preparing, it is preferable to mix | blend SBR or NBR , glass fiber, and an inorganic mineral. SBR or NBR can be used alone or in combination. Although it does not specifically limit as glass fiber, A fiber diameter is 9-13 micrometers and a fiber length can use 90-150 micrometers. The inorganic mineral is not particularly limited, and wollastonite, calcium carbonate, talc, kaolin, mica, clay, silica, calcium hydroxide and the like can be used alone or in combination. Although it does not specifically limit as a hardening | curing agent, Phenolic resin hardening | curing agents, such as hexamethylenetetramine, can be used.

And the phenol resin molding material of this invention can be prepared by knead | mixing the said phenol resin, a filler, and another material with a biaxial kneader etc. FIG. Further, it may be cooled and pulverized and granulated after kneading. Here, the blending amount of the filler is preferably 0.5 to 10% by mass with respect to the total amount of the phenol resin molding material. When the blending amount of the filler is less than 0.5% by mass, it is difficult to obtain the effect of the present invention, and when the blending amount of the filler exceeds 10% by mass, it is difficult to ensure moldability. There is. The securing of moldability means that the molding material has a curing rate or a molding material viscosity in an appropriate range during molding such as injection molding or transfer molding, and molding without molding defects such as unfilled or scraped. Say what you can do. In the case of a phenol resin molding material for a commutator, the blending amount of the phenol resin is 25 to 35% by mass, the blending amount of the filler is 0.5 to 10% by mass, and the SBR is based on the total amount of the phenol resin molding material. Alternatively, the NBR content is preferably 0.1 to 5 mass%, the glass fiber content is 40 to 65 mass%, and the inorganic mineral content is preferably 1 to 15 mass%. When the blending amount of the phenol resin deviates from the above range, the strength of the commutator that is a molded product may be lowered, or it may be difficult to knead uniformly, making it difficult to make a material. When the blending amount of SBR or NBR is less than 0.1% by mass, it becomes difficult to suppress the dimensional change of the molded product due to mechanical load or thermal history, and when the blending amount of SBR or NBR exceeds 5% by mass, it is uniformly It is difficult to knead and materialization may be difficult. If the blending amount of the glass fiber is less than 40% by mass, the strength of the commutator as a molded product may be lowered. If the blending amount of the glass fiber exceeds 65% by mass, it is difficult to knead uniformly. May become difficult. When the blending amount of the inorganic mineral is less than 1% by mass, it may be difficult to uniformly knead and there is a risk that the productivity may be reduced. When the blending amount of the inorganic mineral exceeds 15% by mass, There is a risk that the mechanical strength may decrease and the product characteristics may not be satisfied.

In manufacturing a molded product such as a commutator and its peripheral parts using the phenol resin molding material, the phenol resin molding material is molded by a hot press. As a molding method, injection molding, transfer molding, compression molding, or the like can be employed, but the molding method is not limited thereto. In the case of injection molding, the molding conditions may be a temperature of 150 to 190 ° C., a pressure of 88 to 137 MPa (900 to 1400 kgf / cm ² ), and a time of 20 seconds or more, but are not limited thereto. In the case of other molding methods, molding can be performed according to these molding conditions.

  As mentioned above, the required level in terms of dimensions of each part has been increased due to the need for noise reduction of automobiles. Especially, among automobile parts, commutators that are sliding parts are mounted after the commutator processing and after the automobile is mounted. Therefore, there is a demand for reduction of abnormal noise generated due to dimensional changes caused by the use of the above. Factors that cause dimensional changes that occur during mounting after commutator processing are due to molding shrinkage during molding and dimensional changes during annealing performed after processing. As a result, commutator molded products (resins) and copper There may be gaps between the segments. In conventional molding materials, this gap is large, and the roundness as a commutator is reduced by local mechanical load and electrical / thermal load on the terminal part due to the fusing process performed in the mounting process. The deterioration of the step between the molded product and the copper segment occurs due to the deterioration and the centrifugal force at the time of rotation of the motor, increasing the noise when the motor is driven.

  Moreover, as a factor of the dimensional change of the commutator that occurs after being mounted on a vehicle, there is a dimensional change due to heat received from the engine part of the vehicle or heat generated when the motor itself generates heat. With conventional molding materials, the dimensional change of the molded product in a hot atmosphere environment is greatly generated, and the thermal history received after mounting on the automobile causes deterioration of the step generated between the commutator molded product and the copper segment. Abnormal noise during driving is increased.

  Therefore, the phenol resin molding material of the present invention is blended with the filler as described above, whereby a cured phenol resin (molded product) generated during an annealing process performed after the commutator is molded. It is possible to suppress the shrinkage of the material, and at the same time, it may be possible to expand, and as a result, it is possible to suppress the gap generated between the molded product and the copper segment when processing the commutator. In addition, it is possible to suppress the dimensional change of the molded product even in a hot atmosphere environment, which can greatly improve the deterioration of roundness after mounting the commutator and the deterioration of the step after mounting the car. is there. Therefore, it is possible to suppress the generation of abnormal noise when the motor is driven from these two points.

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

A predetermined amount of materials shown in Table 1 were blended (unit: mass%) and mixed for 1 minute. Next, this mixture was kneaded at a product temperature of 100 to 110 ° C. for 3 minutes with a twin-screw kneader. Thereafter, the kneaded material was cooled and pulverized, granulated, and Examples 1, 2, 6, 8, 10, 11, 12, 15, Reference Examples 3, 4, 5, 7, 9, 13, 14 and Comparative Examples. 1 to 3 phenolic resin molding materials were obtained. The materials used are as follows.

Novolac-type phenolic resin ... BRP590P manufactured by Showa Polymer Co., Ltd.
Resol-type phenol resin: manufactured by Matsushita Electric Works, Ltd. The molar ratio of formaldehyde F to phenol P is F / P = 1.84, and these are reacted at 110 ° C. for 6 hours using a zinc acetate catalyst, and obtained by dehydration under reduced pressure. With a molecular weight of GPC and a number average molecular weight of 650
SBR: Nippon Zeon Styrene Butadiene Rubber
NBR: Nitrile rubber made by ZEON, Nippon 1411
Inorganic mineral (inorganic filler): manufactured by NYCO, Wollastonite NYAD400
Glass fiber: CS3E-479S manufactured by Nittobo Co., Ltd. (fiber diameter average φ12 μm, fiber length 3 mm)
Hardener ... Mitsui Toatsu Co., Ltd. S-4, Hexamethylenetetramine Lubricant ... Carnauba wax, Dainichi Chemical Co., Ltd. Carnauba F-1
Dye ... Solvent Black, Orient Chemical Industry Co., Ltd. SAP-L
Filler A (without graft layer): Paracron produced by Negami Co., Ltd., alkyl acrylate, m = 4 carbon atoms
Filler B (without graft layer): Paracron produced by Negami Co., Ltd., alkyl acrylate, carbon number m = 10
Filler C (without graft layer): Mitsubishi Rayon Co., Ltd. Sumipex, alkyl methacrylate, carbon number m = 1
Filler D (with graft layer): Mitsubishi Rayon Co., Ltd. SRK-200, alkyl methacrylate, carbon number m = 4, type of graft layer acrylonitrile rubber, dimethylsiloxane copolymer Phenol resin molding material obtained above A test piece was prepared using. The test piece was formed by injection molding using a test piece mold having a JIS bending test shape. The mold temperature at this time was 170 ° C., the curing time was 90 seconds, and the injection pressure was 128 MPa.

  The following performance was evaluated using the above-mentioned phenol resin molding material and test piece.

(1) Dimensional change during annealing (shrinkage rate)
The dimensional change rate with respect to the mold size after annealing of the test piece was measured. This value is preferably smaller in absolute value. The annealing conditions were set to 210 ° C. × 7 hours after 180 ° C. × 3 hours.

(2) Dimensional Change after Standing at High Temperature The test piece annealed in (1) was treated at 200 ° C. for 500 hours, and the dimensional change rate before and after the treatment was measured.

(3) Formability (cutting time s)
Extrusion flow test [JIS K 6911] was performed. The implementation conditions were 40 g / 160 ° C./29.4 MPa. This evaluation is preferably 60 to 80 seconds in actual molding processability.

(4) Molded product strength (bending strength) MPa
The strength evaluation was performed according to JIS bending strength [JIS K 6911]. This evaluation is preferably 150 MPa or more in view of product characteristics.

  The results are shown in Table 1.

As is apparent from Table 1, the phenol resin molding materials of Examples 1, 2, 6, 8, 10, 11, 12, 15 and Reference Examples 3 , 4 , 5 , 7 , 9 , 13, and 14 are comparative examples 1. The dimensional change during annealing and the dimensional change after standing at high temperature were smaller than those of ˜3.

Claims (5)

In a phenol resin molding material in which a filler is blended with a phenol resin, the filler is a structure of the following formula (1) or (2) and m is an integer of 1 to 10 or an alkyl acrylate ester material or an alkyl methacrylate ester System material is used , phenol resin content is 25-35% by mass, filler content is 0.5-10% by mass, SBR or NBR content is 0.1-5% by mass, glass fiber content A phenol resin molding material characterized in that the amount is 40 to 65% by mass and the amount of inorganic mineral is 1 to 15% by mass .

  The phenol resin molding material according to claim 1, wherein the filler has a graft layer on the surface. The phenol resin molding material according to claim 2, wherein the graft layer is any one of acrylonitrile / styrene copolymer, methacrylic acid alkyl ester / styrene copolymer, and methacrylic acid alkyl ester polymer .   The phenol resin molding material according to any one of claims 1 to 3, wherein a blending amount of the filler is 0.5 to 10% by mass. A molded product comprising the phenol resin molding material according to any one of claims 1 to 4 molded by a hot press .