JP2878044B2 - Phenolic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides a high balance between static strength such as bending strength and toughness or flexibility and heat resistance by blending a partially crosslinked NBR and an inorganic filler with a resole resin. The present invention relates to a phenolic resin composition which has properties and has good fluidity and excellent injection moldability.

[0002]

2. Description of the Related Art Phenolic resin molding materials are excellent in heat resistance, dimensional stability, moldability and the like, and have been used in basic industrial fields such as automobiles, electricity and electronics. In particular, recently, in the field of automobiles, attempts have been actively made to reduce costs by replacing metal parts using iron, aluminum, zinc or the like with glass fiber reinforced phenol resin molded products. However, thermosetting resin compositions, such as phenolic resins, have the advantage of excellent heat resistance, but also have the drawback of being very brittle and fragile due to their cross-linked structure, which is expanding their application to metal parts. Is a factor that has been alienated. Many attempts have been made in the past to remedy this drawback, i.e. toughness or flexibility. For example, a molding material generally called a chip material made into a material with a Henschel mixer, a super mixer, or a material obtained by impregnating a glass roving with a phenol varnish, drying the solvent, and removing a solvent, and cutting the prepreg into an appropriate length. there are, these molding materials Charpy impact strength at former 5~12kgcm / cm ^2, the latter in 50~100kgcm / cm ²
Shows a very high value. However, in any case, the adhesion between the filler and the substrate is reduced, and the static strength is extremely reduced. In the latter case, there is a drawback that the molding method is limited to only compression molding.

[0003] The present applicant discloses in Japanese Patent Application Laid-Open No. Hei 3-137151 that a carboxyl-modified NBR (acrylonitrile-butadiene rubber) is added to a system using a resole resin and a novolak resin together, and the system is strengthened with an inorganic filler to improve heat resistance. It was proposed that a molding material with excellent balance between high toughness and static strength could be obtained. It is recommended that the carboxyl-modified NBR used here has an SP value of 9 to 10. However, since the presence of a carboxyl group increases the SP value, a general NBR butadiene having the same SP value,
It has a binding ratio different from the allylonitrile binding ratio. Further, since the carboxyl group participates in the reaction when the resin is cured, the melt viscosity at the time of molding is very high as compared with the case where NBR having the same SP value is added. Therefore, in a mold having a complicated shape, poor filling may occur while having high thermal stability. As described above, a phenolic resin molding material having excellent heat resistance, a balance between static strength and toughness or flexibility, and further excellent flowability has not been obtained.

[0004]

The parts used in an engine room of a motor vehicle include vibrations of 3 to 40 G and 1
It is exposed to temperatures of 50 to 200 ° C. and environmental conditions such as stones jumping during running. Conventionally, in order to replace a metal part with a resin, it is necessary to have toughness to withstand these conditions. Further, as a material for a commutator as a motor component, a molding material having excellent shaft press-fitting property and excellent heat resistance is required. The inventor of the present invention has conducted intensive studies to provide a molding material that can respond to such parts, and as a result, has excellent heat resistance, and has a high balance between static strength and toughness or flexibility, and has a high production efficiency. They have found a way to obtain a material that can be injection molded with good quality.

[0005]

The present invention SUMMARY OF THE INVENTION may, resole resin 25 to 55 parts by weight, partially crosslinked NBR2~8 parts, mainly composed of inorganic filler 35-70 parts by weight (novolac trees
(Excluding those containing fat) is a phenolic resin composition that gives a high level of balance between static strength such as bending strength and tensile strength and toughness or flexibility and heat resistance, and has good fluidity, It is intended to provide a phenolic resin molding material having excellent injection moldability. The resole resin used here may be of the dimethylene ether type or the methylol type, and may be used alone or in combination. It is preferable to use the dimethylene ether type and the methylol type in a ratio of 20:80 to 60:40. The softening point (ball ring method) of the resole resin is preferably 70 ° C. or more in terms of handling of the resin and characteristics of the molded product.

[0006] The partially crosslinked NBR is generally obtained by crosslinking and polymerizing a double bond of butadiene and acrylonitrile at an appropriate ratio at the monomer stage, and is a crosslinked portion of normal acrylonitrile butadiene. Is usually 3% or less. However, if the cross-linking ratio is high, the compatibility with the resin deteriorates, so that the cross-linking at a ratio of 1% or less is preferable. Further, the bonding ratio between acrylonitrile and butadiene is preferably adjusted to an SP value of about 9 to 10 in consideration of compatibility with the resole resin. The molecular weight of the partially cross-linked NBR is not particularly limited, but is preferably about 200,000 to 500,000 in consideration of roll workability.

[0007] The inorganic filler includes calcium carbonate, calcined clay, unfired clay, mica, silica, wollastenite,
Magnesium hydroxide, aluminum hydroxide, glass fiber, alumina fiber and the like can be used alone or in combination. In particular, if at least 50 to 60% of the inorganic filler is made of glass fiber or alumina fiber, it is more effective to improve the static strength and impact strength. Furthermore, if a coupling agent such as aminosilane or epoxysilane is used to increase the adhesion between the filler and the resin, it is effective in improving the strength and heat resistance.

[0008]

According to the present invention, there is provided a phenol resin composition which is capable of performing stable injection molding, and has a property in which static strength such as bending strength and tensile strength and toughness or flexibility and heat resistance are well balanced. 25 to 55 parts by weight (preferably 25 to 40 parts by weight) of the resole resin, partially crosslinked NB
R2 to 8 parts by weight (preferably 3 to 6 parts by weight), 35 to 70 parts by weight (preferably 55 to 65 parts by weight) of an inorganic filler as a main component, and further a pigment usually used for a phenolic resin molding material After uniformly mixing raw materials such as a release agent and a curing accelerator, the mixture is heated and kneaded by a kneader such as a roll, a co-kneader, a twin-screw extruder and the like, and then pulverized. When the content of the resole resin is 25 parts by weight or less, moldability tends to be deteriorated due to a small amount of the resin component, and various characteristics of a molded product are deteriorated. On the other hand, when the amount is 55 parts by weight or more, workability at the time of manufacturing a molding material is inferior, and volatile matter at the time of curing increases, so that injection molding becomes difficult. In addition, molding shrinkage is large, and the strength of the molded product tends to decrease. If necessary, the above-mentioned kneaded product can be pelletized by using an extrusion granulator before cooling.

When the content of the partially crosslinked NBR is less than 2% by weight, the effect of improving the toughness is small, and when it is more than 8% by weight, the melt viscosity is high when the material is formed into a molding material. Sexuality is reduced. When the compounding amount of the inorganic filler is 35% by weight or less, the proportion of the inorganic filler is small, so that the workability during the production of the molding material is inferior, and the volatile matter at the time of curing increases, so that injection molding becomes difficult. In addition, molding shrinkage is large, and the strength of the molded product also decreases. On the other hand, when the content is 70% by weight or more, the moldability deteriorates, and various characteristics of the molded product deteriorate. The thus obtained phenolic resin composition having excellent toughness, flexibility and static strength of the present invention can be used as a starter motor component mounted in an automobile engine room, a commutator requiring heat resistance, and the like. Applicable.

[0010]

The present invention will be described below with reference to examples and comparative examples. “Parts” is “parts by weight”. << Example 1 >> (A) 18 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) dimethylene ether type resole 17 (PR-53529 manufactured by Sumitomo Durez Co., Ltd.) (C) Partially cross-linked NBR PNC-383 (manufactured by Nippon Synthetic Rubber Co., Ltd .: crosslinking ratio: 0.8%, SP value: 9.7) (D) Glass fiber (ECSO15B154H manufactured by NEC Corporation) 50 (E) Fired clay 10 (F) ) Pigment, release agent, etc. 4 were uniformly mixed and kneaded with a heating roll to form a molding material.

Example 2 (A) 18 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) dimethylene ether type resole 17 (PR-53529 manufactured by Sumitomo Durez Co., Ltd.) (C) Partially cross-linked NBR PNC-38 (manufactured by Nippon Synthetic Rubber Co., Ltd.) 4.5 (D) Glass fiber (ECSO15B154H manufactured by NEC Corporation) 40 (E) Fired clay 20 (F) Pigment, release agent, etc. 4 Were uniformly mixed and kneaded with a heating roll to form a molding material.

Example 3 (A) 20 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) dimethylene ether type resole 10 (PR-53529 manufactured by Sumitomo Durez Co.) (C) Partially crosslinked NBR PNC-38 (manufactured by Nippon Synthetic Rubber Co., Ltd.) 3 (D) Glass fiber (ECSO15B154H manufactured by NEC Corporation) 55 (E) Fired clay 10 (F) Pigment, mold release agent, etc. 4 They were mixed and kneaded with a heating roll to form a molding material.

Example 4 (A) 30 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) Partially cross-linked NBR PNC-38 (manufactured by Nippon Synthetic Rubber Co., Ltd.) 3 (C) Glass Fiber (ECSO15B154H, manufactured by NEC Corporation) 55 (D) Fired clay 10 (E) Pigment, release agent, etc. 5 were uniformly mixed and kneaded with a heating roll to form a molding material.

Comparative Example 1 (A) 20 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) dimethylene ether type resole 18 (PR-53529 manufactured by Sumitomo Durez Co., Ltd.) (C) Glass fiber (ECSO15B154H, manufactured by NEC Corporation) 50 (D) Fired clay 10 (E) Pigment, release agent, etc. 4 were uniformly mixed and kneaded with a heating roll to form a molding material.

Comparative Example 2 (A) 18 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) dimethylene ether type resole 17 (PR-53529 manufactured by Sumitomo Durez Co., Ltd.) (C) Carboxylated NBR PNC-25 3 (Nippon Synthetic Rubber Co., Ltd .: Carboxyl group 4 mol%, SP value 9.3) (D) Glass fiber (ECSO15B154H manufactured by NEC Corporation) 50 (E) Fired clay 10 (F) Pigment, release agent, etc. 4 were uniformly mixed and kneaded with a heating roll to form a molding material.

Comparative Example 3 (A) 20 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) dimethylene ether type resole 10 (PR-53529 manufactured by Sumitomo Durez Co.) (C) Normal NBR PN-20HA3 (manufactured by Nippon Synthetic Rubber Co., Ltd .: SP value 9.6) (D) Glass fiber (ECSO15B154H manufactured by NEC Corporation) 55 (E) Fired clay 10 (F) Pigment, mold release Agent 4 was uniformly mixed and kneaded with a heating roll to form a molding material.

Comparative Example 4 (A) 20 parts of methylol type resole (PR-51141 manufactured by Sumitomo Durez Co., Ltd.) (B) Novolak (weight average molecular weight 6500) 10 (C) partially cross-linked NBR PNC-38 (Nippon Gosei) 3 (D) Glass fiber (ECSO15B154H manufactured by NEC Corporation) 55 (E) Fired clay 10 (F) Pigment, release agent, etc. 4 Uniformly mix, knead with heated roll, and mold Materialized.

The following evaluations were carried out on Examples 1 to 4 and Comparative Examples 1 to 4, and the results are shown in Table 1 together with the composition of the molding material.

[Table 1]

(1) Monohole flow The measurement was performed according to JIS K 6911. However, the mold temperature is 140 ° C,
The pressure was 150 kgf / cm ² . (2) Flexural strength 18 test pieces which were transfer-molded according to JIS K 6911
After heating and aging at 0 ° C. for 8 hours, measurement was carried out using Tensilon of Toyo Baldwin Co., Ltd. (3) Heat deformation temperature
After heat aging at 0 ° C. for 8 hours, the temperature was measured with a thermal deformation temperature tester of Toyo Seiki Co., Ltd. (4) Shaft press-fitting An outer diameter of 33 mm, which is transfer-molded according to JIS K 6911,
A copper wire is wound around the outer periphery of a cylindrical molded product having an inner diameter of 11 mm and a length of 35 mm, and a taper pin having a taper of 0.5 / 80 is press-fitted into the molded product at a speed of 5 mm / min. The press fit (bulge of the inner diameter at the time of breaking, that is, the inner diameter at the time of breaking minus the original inner diameter (11 mm)) was measured.

In Examples 1 to 3, the dimethylene ether type resole and the methylol type resole are used in combination as the resole resin, and an appropriate amount of partially crosslinked NBR is blended, so that the bending strength is good without deteriorating other properties. Thus, a molding material having excellent heat resistance was obtained. In Example 4, only a methylol type resole was used as a resole resin, and an appropriate amount of partially crosslinked NBR was blended with the resole resin. Although the bending strength is slightly reduced, other characteristics are as good as in Examples 1 to 3.

Comparative Example 1 is a case in which the partially crosslinked NBR is not blended. Although the bending strength and the heat resistance are good, the flexibility is extremely inferior, so that the shaft press-fitting property is poor and the object of the present invention is not to be considered. It cannot be used for any purpose. Comparative Example 2 was partially crosslinked N
Although carboxy-modified NBR was used instead of BR, the bending strength and shaft press-fitting properties were good, but
The moldability is remarkably reduced and the practicality is poor. Comparative Example 3 uses normal NBR instead of partially cross-linked NBR, and is inferior in bending strength and heat resistance. Comparative Example 4 is a case where a methylol-type resole and a novolak resin are used in combination,
Both have practical problems because of their poor heat resistance.

[0022]

The phenolic resin composition of the present invention is obtained by mixing a methylol type or dimethylene ether type resole resin with an inorganic filler such as partially cross-linked NBR and glass fiber to provide mechanical strength and toughness or toughness. It has good flexibility, excellent heat resistance, and excellent fluidity during molding, and is suitable for molding molded products with complicated shapes.
It greatly promotes the replacement of metal parts such as automobile parts with plastic parts. Furthermore, it is very suitable for commutators.

Claims (3)

(57) [Claims] (1) 25 to 55 parts by weight of a resole resin,
(2) 2-8 parts by weight of partially crosslinked NBR, (3) inorganic filler 40
Up to 70 parts by weight (including novolak resin
Except in) a phenolic resin composition. 2. The phenolic resin composition according to claim 1, wherein the resole resin comprises a dimethylene ether type resole and a methylol type resole. 3. The phenolic resin composition according to claim 1, wherein the glass fiber content of the inorganic filler is 50% by weight or more.