JP3915045B2 - Structural part molding material in machining center and structural part molding in machining center - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a technique capable of providing a carbon fiber-reinforced phenolic resin molded article having high strength, high rigidity, particularly high flexural modulus, dimensional stability, and low specific gravity. Furthermore, it has excellent fluidity, good moldability, for example, a molded product obtained by compression molding has high strength, particularly high impact strength, high rigidity, excellent sliding characteristics, and The present invention relates to a technique that has a low specific gravity and is useful as a metal substitute molding material, and can be suitably used for, for example, a tool change arm, a tool change holder, or various structural parts in a machining center.
[0002]
[Prior art]
  In recent years, replacement of a metal material with a plastic material has been attempted from the viewpoint of reducing the weight of materials such as molded products and molded parts and reducing costs. In other words, various plastics have been studied and used in the fields of molded products and molded parts that conventionally used metals.
  Among them, recently, phenol resins have been reviewed as metal substitute materials by taking advantage of the excellent properties of phenol resins. In general, phenol resin molding materials include cellulose fibers, plastic fibers, asbestos, glass fibers, carbon fibers, whiskers, and other organic fibers, or inorganic fibers, or talc, clay, mica, wood flour. Pulp or the like is used as a reinforcing material (filler).
[0003]
  By the way, when a phenol resin is used as a metal substitute material, the material is required to have excellent properties such as mechanical strength, heat resistance, dimensional stability, and sliding characteristics.
  In order to satisfy such required performance, chopped strands of glass fiber or carbon fiber are used as a reinforcing material.
  However, when glass fiber is used as a reinforcing material, even if a large amount of glass fiber is blended, the expected high rigidity cannot be obtained, and when it is used in a large amount, the moldability deteriorates, and Weight reduction is not achieved.
  On the other hand, when carbon fibers are used, the carbon fibers are more easily defibrated than the glass fibers, the wettability with the resin is poor, the handling is difficult, and a sufficient reinforcing effect cannot be exhibited.
[0004]
  Therefore, various methods are known when carbon fiber is used as a reinforcing material.
  For example, a so-called carbon fiber reinforced phenol resin molding material using carbon fiber as a structural material is impregnated with a phenol resin in a substrate such as carbon paper, carbon fiber woven fabric, carbon fiber mat, or non-woven fabric, and dried and precured. And used as a prepreg. In particular, most of the structural members are prepreg methods.
[0005]
  Moreover, when using what is called a chopped strand, without using base materials, such as a woven fabric of carbon fiber, a carbon fiber mat, and a nonwoven fabric, the method of giving a special surface treatment to carbon fiber and using it is proposed.
  For example, JP-A-1-172428 discloses the use of a PAN-based carbon fiber that has been subjected to an air oxidation treatment and a titanate-based coupling agent treatment.
  A method using special carbon fibers has also been proposed.
  For example, in JP-A-2-64132, carbon fibers having an onion structure and a crystal layer thickness of 25 to 200 mm are used as carbon fibers, and phenol resin and acrylonitrile-butadiene copolymer are used as matrix resins. It is disclosed to use.
  JP-A-2-255864 discloses the use of vapor grown carbon fiber having a fiber diameter of 0.05 to 5 μm.
  In Japanese Patent Laid-Open No. 2-298554, a vapor grown carbon fiber and / or a carbon fiber having a surface spacing d (Å) of 3.47 to 3.43, an aspect ratio of 50 to 500, and a diameter of 5 μm or less is heat-treated. It is disclosed that a graphite whisker having an interplanar spacing d (Å) of 3.43 to 3.35 is used.
  Japanese Patent Laid-Open No. 6-136142 discloses a method in which a carbon fiber is heated in air at 440 ° C. to introduce a carboxy group, and after being immersed in a toluene solution of diethylenetriamine, heated is kneaded with a phenol resin. .
  Japanese Patent Laid-Open No. 3-59060 discloses a method in which a string-like body composed of short fibers and / or long fibers is impregnated with a phenol resin liquid, and after drying by heating, this is cut and used.
[0006]
  As described above, until now, when carbon fiber is used as a reinforcing material, a so-called prepreg obtained by impregnating a base material such as a woven fabric, a mat, or a nonwoven fabric with a resin, and preliminarily drying and curing is generally used. In particular, the prepreg method is mostly used as the structural member.
  However, the method of forming and using a prepreg is unsuitable for obtaining a molded product having a complicated shape using a molding die.
  In addition, as described above, even when carbon fiber is treated specially or special carbon fiber is used, the bending elastic modulus is 4000 kgf / mm by a molding method such as compression molding.²A molded product exhibiting the above high rigidity is not known. Even if a highly rigid molded product is obtained, the cost increases, which is not common.
[0007]
[Problems to be solved by the invention]
  Therefore, the problem to be solved by the present invention is that it is not necessary to perform a special surface treatment on the carbon fiber itself as a reinforcing material, and using a commercially available chopped strand carbon fiber, it is excellent in molding processability and fluidity. High elasticity, high rigidity, and excellent sliding characteristicsStructural parts in machining centersIt is to provide the technology that can be obtained.
[0008]
[Means for Solving the Problems]
  The above issues areA molding material for a structural part in a machining center, the molding material beingPhenolic resin molding material containing phenolic resin and carbon fiber as main componentsAnd
  The ratio of the phenolic resin and carbon fiber in the phenolic resin molding material is such that the carbon fiber is 50 to 80 parts by weight with respect to 20 to 40 parts by weight of the phenolic resin,
  The phenolic resin molding material is flaky or scaly,
  The carbon fiber isThe average fiber length is 3.0 to 8.0 mm, the average fiber diameter is 6 to 12 μm, the aspect ratio is 250 to 1500, and the density is 1.7 to 2.2 g / cm. ³ The tensile modulus is 2 × 10 ⁴ kgf / mm ² It is the above chopped strand
It is characterized byStructural part molding materials in machining centersSolved by.
[0010]
  That is, the phenol-based resin molding material having the above characteristics is obtained by using a commercially available chopped strand carbon fiber because the carbon fiber itself as a reinforcing material does not need to be subjected to a special surface treatment. Therefore, it can be obtained at a low cost. And molded products with excellent moldability, fluidity, high elasticity, high rigidity, and excellent sliding properties(Structural parts in machining centers)Is obtained.
[0011]
  Moreover, the said subject mixes 20-40 weight part phenolic resin, a predetermined amount of additive, and a carbon fiber with an average fiber length of 3.0-9.0 mm by 50-80 weight part. A mixing step;
  After the mixing step, a granulation step of granulating at a temperature of 40 ° C. or lower while adding a solvent;
  A drying step of drying at a temperature of 85 to 110 ° C. after the granulation step.
It solves by the manufacturing method of the phenol-type resin molding material characterized by comprising.
  Among them, after mixing 20 to 40 parts by weight of phenolic resin and a predetermined amount of additive, 50 to 80 parts by weight of carbon fiber having an average fiber length of 3.0 to 9.0 mm is mixed with this. A mixing step to
  After the mixing step, a granulation step of granulating at a temperature of 40 ° C. or lower while adding a solvent;
  A drying step of drying at a temperature of 85 to 110 ° C. after the granulation step.
It solves by the manufacturing method of the phenol-type resin molding material characterized by comprising.
[0012]
  In particular, 20 to 40 parts by weight of a phenolic resin, a predetermined amount of additives, 50 to 80 parts by weight, an average fiber length of 3.0 to 9.0 mm, an average fiber diameter of 6 to 12 μm, and an aspect ratio of 250-1500, density 1.7-2.2 g / cm³The tensile modulus is 2 × 10⁴kgf / mm²A mixing step of mixing the above chopped strand carbon fibers;
  After the mixing step, a granulation step of granulating at a temperature of 40 ° C. or lower while adding a solvent;
  A drying step of drying at a temperature of 85 to 110 ° C. after the granulation step.
It solves by the manufacturing method of the phenol-type resin molding material characterized by comprising.
  Among them, after mixing 20 to 40 parts by weight of a phenolic resin and a predetermined amount of additives, 50 to 80 parts by weight, an average fiber length of 3.0 to 9.0 mm, and an average fiber diameter of 6 ~ 12μm, Aspect Ratio 250 ~ 1500, Density 1.7 ~ 2.2g / cm³The tensile modulus is 2 × 10⁴kgf / mm²A mixing step of mixing the above chopped strand carbon fibers;
  After the mixing step, a granulation step of granulating at a temperature of 40 ° C. or lower while adding a solvent;
  A drying step of drying at a temperature of 85 to 110 ° C. after the granulation step.
It solves by the manufacturing method of the phenol-type resin molding material characterized by comprising.
[0013]
  In other words, according to the above manufacturing method, a phenolic resin molding material that is excellent in molding processability, fluidity, high elasticity, high rigidity, and excellent in sliding characteristics can be obtained at a low cost. It is obtained by.
[0014]
  Also molded using the above molding materialsA structural part in a machining center,
  The structural component has a flexural modulus of 4000 kgf / mm. ² As described above, the specific bending elastic modulus is 2600 kgf / mm. ² Is more than
Structural parts in machining centers characterized bySolved by.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
  The molding material of the present invention is a phenolic resin molding material containing a phenolic resin and carbon fiber as main components, wherein the ratio of the phenolic resin and carbon fiber in the phenolic resin molding material is the phenolic resin. The carbon fiber is 50 to 80 parts by weight with respect to 20 to 40 parts by weight, and the phenolic resin molding material is flaky or scaly, and the carbon fiber has an average fiber length of 3 0.0 to 8.0 mm. In particular, the carbon fiber has an average fiber length of 3.0 to 8.0 mm, an average fiber diameter of 6 to 12 μm, an aspect ratio of 250 to 1500, and a density of 1.7 to 2.2 g / cm.³The tensile modulus is 2 × 10⁴kgf / mm²It is the above chopped strand.
[0016]
  The manufacturing method of the molding material of the present invention includes 20 to 40 parts by weight of a phenolic resin, a predetermined amount of additives, 50 to 80 parts by weight of carbon fibers having an average fiber length of 3.0 to 9.0 mm, Mixing step, granulating step of granulating at a temperature of 40 ° C. or less while adding a solvent after the mixing step, and drying step drying at a temperature of 85 to 110 ° C. after the granulating step It comprises. In particular, 20 to 40 parts by weight of a phenolic resin and a predetermined amount of additive are mixed, and then 50 to 80 parts by weight of carbon fiber having an average fiber length of 3.0 to 9.0 mm is mixed therewith. A mixing step, a granulation step of granulating at a temperature of 40 ° C. or less while adding a solvent after the mixing step, and a drying step of drying at a temperature of 85 to 110 ° C. after the granulation step. It has. As the additive, for example, a filler, a pigment, a release agent, and a curing agent as required are used. The carbon fiber used has an average fiber length of 3.0 to 9.0 mm, an average fiber diameter of 6 to 12 μm, an aspect ratio of 250 to 1500, and a density of 1.7 to 2.2 g / cm.³The tensile modulus is 2 × 10⁴kgf / mm²It is the above chopped strand.
[0017]
  The resin molded product of the present invention is molded using the phenolic resin molding material or the phenolic resin molding material obtained by the method for producing the molding material, and has a flexural modulus of 4000 kgf / mm.²As described above, the specific bending elastic modulus is 2600 kgf / mm.²That's all.
[0018]
  This will be described in more detail below.
  The molding material of the present invention has good moldability. A molded product obtained by, for example, compression molding the molding material has a low specific gravity and an impact strength (with an Izod and a notch) of 30 kgf-cm / cm.²With the above, the flexural modulus is 4000 kgf / mm²The specific bending elastic modulus is 2600 kgf / mm²This is a carbon fiber reinforced phenolic resin molded product having almost no molding shrinkage, high strength, high rigidity and excellent dimensional stability.
[0019]
  The molding material of the present invention comprises 20 to 40 parts by weight of a phenolic resin, a predetermined amount of filler, a predetermined amount of pigment, a predetermined amount of release agent, and a predetermined amount of curing agent as required. Is mixed using a mixer (for example, a low-speed rotary stirring mixer having a stirring blade (for example, an ordinary open kneader)), particularly while maintaining a temperature of 40 ° C. or lower, and 50 to 80 parts by weight. Carbon fibers (carbon fibers having an average fiber length of 3.0 to 9.0 mm) are added and mixed, and then dried, and the mixture is granulated (for example, a high-speed rotary stirring mixer (for example, a Henschel mixer, a spar mixer). )), And granulating while adding a low-boiling solvent such as methanol while maintaining a temperature of 40 ° C. or lower, followed by drying at a temperature of 85 to 110 ° C.
[0020]
  The mixing time by the low-speed rotary stirring mixer after adding the carbon fiber is generally around 30 minutes. That is, the time required for the mixture to change from clay (paste) to scale or flake is usually 20 to 40 minutes. When the mixing time is long, the carbon fiber is cut frequently, and the desired predetermined physical properties cannot be obtained.
[0021]
  The obtained mixture is dried (primary drying) using a drier such as a hot air circulating drier at a temperature of about 100 ° C., usually 85 to 110 ° C., until a target flow value (spiral flow) is reached. The time required for this drying is usually around 60 minutes. When the drying temperature is low, the time required for drying becomes long, which is not preferable in terms of work operation. On the other hand, when the drying temperature is too high, it is difficult to carry out work operations such as adjustment of the flow value of the material, and variations in drying are likely to occur.
[0022]
  Using a high-speed rotary stirring mixer (eg, Henschel mixer, Spur mixer), maintaining a temperature of 40 ° C. or lower while adding a low-boiling organic solvent such as methanol or acetone to a scaly or flaky mixture, Stir and granulate. The time required for granulation is within 10 minutes, usually 4 to 6 minutes. In a dryer such as a hot-air circulating dryer after granulation, drying is performed (secondary drying) at a temperature of about 100 ° C., usually 85 to 110 ° C. This drying mainly volatilizes the remaining solvent. The time required is usually around 40 minutes, and a target flow value (spiral flow) is obtained.
[0023]
  The amount of the low-boiling organic solvent used is 3.0% by weight or less, usually 1.0 to 2.0% by weight, based on the weight of the mixture charged in the mixer. When the amount of the solvent used is large, the shape of the granulated product tends to be large. On the other hand, when the amount is small, the granulated product is poorly shaped and it is difficult to obtain a molding material having a good shape.
[0024]
  In the molding material of the present invention, the phenolic resin is used in the range of 20 to 40 parts by weight in the total blend. When the blending ratio of the phenolic resin is less than the above range, the kneading operation cannot be performed satisfactorily, the resin is not sufficiently dispersed, and a molding material having a good flow cannot be obtained. On the contrary, when the ratio of the resin is large, it is difficult to obtain sufficient mechanical strength. Therefore, the proportion of phenolic resin used is within the above range, but is preferably in the range of 25 to 35 parts by weight in the total formulation.
[0025]
  In the present invention, the phenolic resin is used as a liquid resin having a resin concentration of 65 to 75%. When a solid resin is used, it is used after adjusting to a predetermined resin concentration with a solvent (for example, methanol, acetone, etc.).
[0026]
  In the present invention, as described above, the charging order in the low-speed rotary stirring mixer is very preferably that the phenolic resin and the predetermined additive are first mixed and then the carbon fiber is added and mixed. When carbon fiber is charged from the beginning, the carbon fiber is easily cut and it is difficult to obtain a predetermined performance (physical property) as a target.
[0027]
  In the present invention, in order to obtain a molded product having the above-described high impact strength, high rigidity and high elasticity, the damage of carbon fibers is suppressed as much as possible, and the average fiber length in the molding material is 3.0-8. It is important to be within the range of 0.0 mm. When the fiber length is shorter than the above range, it is difficult to obtain a highly rigid and highly elastic molded product, and when the fiber length is longer than the above range, the moldability is poor and a stable molded product cannot be obtained. Even when high strength and high rigidity are exhibited, there are defects such as poor surface condition of the molded product.
[0028]
  The carbon fiber used in the present invention has an average fiber length of 3.0 to 9.0 mm, an average fiber diameter of 6 to 12 μm, an aspect ratio of 250 to 1500, and a density of 1.7 to 2.2 g / cm.³The tensile modulus is 2 × 10⁴kgf / mm²It is the above chopped strand.
  Such carbon fiber may be any of pitch-based carbon fiber, polyacrylonitrile-based carbon fiber, aromatic-based carbon fiber, etc., and does not require any special surface treatment. Any commercially available product that has undergone normal treatment and has a fiber diameter, fiber length, aspect ratio, density, and tensile elastic modulus within the above ranges can be used. Examples of commercially available carbon fibers include Besfight HTA-C6-S, Besfight HTA-C3-S (manufactured by Toho Rayon Co., Ltd.), Besfight HTA-C12-S (manufactured by Toho Rayon Co., Ltd.), Granox And XN-50C-06C (manufactured by Nippon Graphite Fiber Co., Ltd.).
[0029]
  In this invention, the compounding quantity of carbon fiber is the range of 50 to 80 weight% normally in all the compounds, Preferably it is 55 to 75 weight%. When the blending amount of the carbon fiber is less than the above range, a molded product having excellent mechanical properties such as strength, rigidity and elastic modulus cannot be obtained. On the other hand, when the amount is large, molding processability and fluidity are deteriorated, and the surface state of the molded product is also deteriorated.
[0030]
  The phenolic resin in the present invention is an aromatic compound having a phenolic hydroxyl group, specifically, phenolic compounds such as phenol, cresol, xylenol, alkylphenol, resorcinol, and formaldehyde, acetaldehyde, paraformaldehyde, furfural, cyclic formal A synthetic resin obtained by a condensation reaction with an aldehyde such as an acid catalyst or an alkaline catalyst, or a modified resin of the resin, and another thermosetting resin (for example, epoxy resin, amino resin, etc.) And a resin alloy subjected to the co-condensation reaction, a partially thermoplastic resin or a polymer alloy with another resin. Usually, so-called phenolic resins are used.
  In the present invention, the phenolic resin may be any of resol type, novolac type solid and liquid. However, when blended with carbon fiber, it is usually preferred to use it in liquid form. That is, when carbon fiber is kneaded in a solid state, the carbon fiber is greatly broken and the adhesion between the resin and the carbon fiber is also deteriorated.
[0031]
  The molding material according to the present invention can further contain a small amount of inorganic filler such as clay, talc, mica, etc. (about 5 to 10% by weight in the total formulation), if necessary. In addition, various additives blended in the phenolic resin molding material can be used as long as the characteristics of the molding material according to the present invention are not impaired.
[0032]
  Specific examples of the present invention are shown below.
[Example 1]
  As the phenol resin, a liquid resin (resin concentration: 70% by weight) in which a novolak type phenol resin having a number average molecular weight of 1200 was dissolved in 30% methanol was used. As carbon fiber, Toshou Rayon Co., Ltd. Besfight HTA-C6-S (trade name) chopped strand (fiber length 6 mm, fiber diameter 7 μm, density 1.77 g / cm^Three, Tensile modulus 2.4 × 10⁴kgf / mm² ) Was used.
  First, 30 parts by weight of the above phenolic resin (including solids and 4.5 parts by weight of hexamine), 5 parts by weight of filler (mica), 5 parts by weight of the pigment and the release agent are charged in a kneader, Pre-mixed.
  Thereafter, 60 parts by weight of carbon fiber was added and mixed at 30 ° C. for about 30 minutes.
  After mixing, the mixture was dried with a hot air dryer at 95 ° C. for 60 minutes. Then, using a high-speed rotary stirring mixer (Henschel mixer), granulation was carried out while maintaining the temperature at 40 ° C. or lower while adding 2 parts by weight of methanol to the dried mixture.
  This granulated product was dried with a hot air dryer at 95 ° C. for 40 minutes to obtain a flaky molding material.
  Table 1 shows the physical properties of the obtained molding material and molded product.
[0033]
[Example 2]
  As carbon fiber, Toshou Rayon Co., Ltd. Besfight HTA-C6-S (trade name) chopped strand (fiber length 6 mm, fiber diameter 7 μm, density 1.77 g / cm^Three, Tensile modulus 2.4 × 10⁴kgf / mm² ) And Besfight HTA-C3-S (fiber length 3 mm, fiber diameter 7 μm, density 1.77 g / cm, manufactured by Toho Rayon Co., Ltd.)^Three, Tensile modulus 2.4 × 10⁴kgf / mm² ) Was used in the same manner as in Example 1 to obtain a flaky molding material.
  Table 1 shows the physical properties of the obtained molding material and molded product.
[0034]
[Example 3]
  25 parts by weight (as a solid content) of a liquid resin obtained by diluting a solid resol type phenol resin having a number average molecular weight of 500 as methanol to 30% as a phenol resin, and Besphite HTA-C6-S manufactured by Toho Rayon Co., Ltd. as a carbon fiber. (Product Name) Chopped strand (fiber length 6 mm, fiber diameter 7 μm, density 1.77 g / cm^Three, Tensile modulus 2.4 × 10⁴kgf / mm² The mixture was made into a mixture in the same manner as in Example 1, and the mixture was dried in the same manner as in Example 1. Then, the mixture was granulated with a Henschel mixer while adding 2 parts by weight of methanol, and dried at 90 ° C. Thus, a flaky molding material was obtained.
  Table 1 shows the physical properties of the obtained molding material and molded product.
[0035]
[Example 4]
  As the phenol resin, a liquid resin obtained by diluting 50% xylene-modified phenol resin with 30% methanol was used. As carbon fiber, Nippon Graphite Fiber Co., Ltd. Granox XN50-C-06C (trade name) chopped strand (fiber length 6 mm, fiber diameter 10 μm, density 2.10 g / cm)^Three , Tensile modulus 5.0 × 10⁴kgf / mm²) Was used.
  First, 25 parts by weight of the above phenolic resin (including solid content and 3.7 parts by weight of hexamine), 5 parts by weight of the pigment and the release agent were charged in a kneader and mixed in advance.
  Thereafter, 70 parts by weight of carbon fiber was added and mixed at 30 ° C. for about 30 minutes.
  After mixing, the mixture was dried with a hot air dryer at 95 ° C. for 60 minutes. Then, using a high-speed rotary stirring mixer (Henschel mixer), granulation was performed while maintaining the temperature at 25 ° C. while adding 2 parts by weight of methanol to the dried mixture.
  This granulated product was dried with a hot air dryer at 95 ° C. for 40 minutes to obtain a flaky molding material.
  Table 1 shows the physical properties of the obtained molding material and molded product.
[0036]
[Comparative Example 1]
  In Example 1, the same procedure as in Example 1 was performed except that the amount of phenol resin used was 15 parts by weight (including 2.5 parts by weight of hexamine) and the amount of carbon fiber used was 80 parts by weight.
  However, in this example, the resin was not sufficiently impregnated, and a good flaky product was not obtained. And the flow value was small, the moldability was poor, and a good molded product could not be molded.
[0037]
[Comparative Example 2]
  In Example 1, it carried out like Example 1 except the usage-amount of carbon fiber having been 40 weight part and the usage-amount of filler (mica) having been 25 weight part.
  In this example, unlike the case of Comparative Example 1, a flaky molding material was obtained. Table 2 shows the physical properties of the obtained molding material and molded product. As can be seen from Table 2, the comparative example has low mechanical strength, particularly impact strength, and the target strength (30 kgf-cm / cm²Is not obtained.
[0038]
[Comparative Example 3]
  In Example 1, as carbon fiber, 30 parts by weight of Besphite HTA-C3-S and 30 parts by weight of Besphite HTA-C1.5-S chopped strand (fiber length 1.5 mm, fiber diameter 7 μm, density 1 .77 g / cm^Three, Tensile modulus 2.4 × 10⁴kgf / mm²) Was carried out in the same manner as in Example 1 except that.
  The molding material obtained in this example had a small major axis of the flakes and a small shape as a whole. Table 2 shows the physical properties of the obtained molding material and molded product. As can be seen from Table 2, in this comparative example, the fiber length of the carbon fiber in the molding material is short, the target mechanical strength cannot be obtained, and the molding shrinkage is large.
[0039]
[Comparative Example 4]
  In Example 1, as carbon fiber, Besphite HTA-C12-S chopped strand (fiber length 12 mm, fiber diameter 7 μm, density 1.77 g / cm^Three, Tensile modulus 2.4 × 10⁴kgf / mm²) Was carried out in the same manner as in Example 1 except that.
  The molding material obtained in this example had a large flake diameter, a large shape as a whole, a long fiber length in the molding material, poor moldability, and a good molded product could not be obtained.
[0040]
[Comparative Example 5]
  In Example 1, it carried out like Example 1 except the mixing time by the kneader having been 50 minutes.
  Table 2 shows the physical properties of the obtained molding material and molded product. As can be seen from Table 2, the average fiber length of the carbon fibers is short, and the target mechanical strength is not obtained.
[0041]
【Characteristic】
                                      Table 1
                Example 1 Example 2 Example 3 Example 4
Flow (cm) 48 50 38 35
Average fiber length (mm) 5.0 3.8 5.2 5.2
Formability Good Good Good Good
Specific gravity (g / cm^Three1.54 1.54 1.56 1.58
Impact strength (notched, kgf-cm / cm²)
                  35 31 38 40
Bending strength (kgf / mm²) 30 28 33 35
Flexural modulus (kgf / mm²)
                4500 4200 4900 5010
Specific flexural modulus (kgf / mm²)
                2900 2730 3140 3170
Mold shrinkage (%) 0.05 0.05 0.03 0.01
Smoothness Good Good Good Good
                                      Table 2
                              Comparative Example 2 Comparative Example 3 Comparative Example 5
Flow (cm) 55 50 40
Average fiber length (mm) 5.6 2.1 2.4
Formability Good Good Good
Specific gravity (g / cm^Three1.55 1.54 1.54
Impact strength (kgf-cm / cm with notch²) 21 25 26
Bending strength (kgf / mm²) 26 30 28
Flexural modulus (kgf / mm²) 3500 3000 3600
Specific flexural modulus (kgf / mm²2260 1940 2340
Mold shrinkage (%) 0.12 0.20 0.13
Smoothness Good Good Good
(1) Flow (cm): Spiral low method, using a mold engraved with a length (100 cm) in a spiral shape, and tophan-spher molding at a predetermined temperature, pressure, time and material input amount, and extruded. The maximum length of a spiral product.
(2) Average fiber length (mm): The resin content in the molding material is extracted and removed with a solvent, and the remaining carbon fiber is observed and measured with an electron microscope.
(3) Moldability: The filling property and appearance of a molded product compression-molded according to JIS K6915 were visually observed and judged.
(4) Specific gravity (g / cm^Three): According to JIS method.
(5) Impact strength, bending strength, flexural modulus, specific flexural modulus: A test piece was prepared by compression molding and measured according to JIS K6915.
(6) Mold shrinkage (%): A test piece was prepared by compression molding and measured according to JIS K6915.
(7) Smoothness: The surface of a molded product molded by compression molding was visually observed and judged.
[0042]
【The invention's effect】
  The molding material of the present invention has good moldability.
  For example, a molded product obtained by compression molding has low specific gravity, excellent mechanical strength such as impact strength and flexural modulus, extremely low molding shrinkage, high strength, high rigidity, and excellent dimensional stability. Carbon fiber reinforced phenolic resin molded product.

Claims (2)

A molding material for a tool exchange arm or a tool exchange holder that is a structural part in a machining center, the molding material being a phenolic resin molding material containing phenolic resin and carbon fibers as main components,
The ratio of the phenolic resin and carbon fiber in the phenolic resin molding material is such that the carbon fiber is 50 to 80 parts by weight with respect to 20 to 40 parts by weight of the phenolic resin,
The phenolic resin molding material is flaky or scaly,
The carbon fiber has an average fiber length of 3.0 to 8.0 mm, an average fiber diameter of 6 to 12 μm, an aspect ratio of 250 to 1500, a density of 1.7 to 2.2 g / cm ³ , and a tensile elastic modulus. A structural part molding material in a machining center, which is a chopped strand of 2 × 10 ⁴ kgf / mm ² or more. A tool change arm or a tool change holder which is a structural part in a machining center formed by using the molding material of claim 1,
The structural part in a machining center having a flexural modulus of 4000 kgf / mm ² or more and a specific flexural modulus of 2600 kgf / mm ² or more .