JPS6228980B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a phenolic resin molding material for injection molding, transfer molding and compression molding which provides molded products with excellent moldability and impact strength. The phenolic resin molding material of the present invention provides molded products having excellent impact strength in addition to the heat resistance, heat creep resistance, and electrical properties that are the characteristics of phenolic resin. It can be suitably used for parts, mechanical parts such as gears, cams, bearing washers, and seal rings, automobile parts such as connectors and pulleys, and miscellaneous goods such as lacquerware. [Prior art and its problems] Conventionally, phenolic resin molding materials have excellent heat resistance, arc resistance, and electrical properties, but have the problem of relatively low impact strength; for example, the Charpy impact strength is It is about 2 to 3 kgf·cm/cm ² .
Therefore, glass fiber is widely used as a fibrous reinforcing material to improve this impact strength, but molded products obtained by compression molding molding materials using glass fiber have improved impact strength, but have poor sliding properties and Problems include poor abrasion resistance and low impact strength against falling balls. In addition, molded products obtained by injection molding or transfer molding of molding materials using glass fibers may rub due to friction between the fibers, or the fibers may become damaged due to shearing during the production of the molding material or during molding. Since it is easily cut, there is a problem in that the improvement in impact strength of the resulting molded product is substantially small, and the Charpy impact strength is about 4 to 5 Kgf·cm/cm ² . Other materials used as fibrous reinforcing materials include pulp, cotton fabric chips, and asbestos fibers, but each fiber itself has a weak tensile strength, so there is a problem in that the impact strength is not as improved as glass fibers. In addition, synthetic fibers such as polyvinyl alcohol fibers (hereinafter referred to as vinylon fibers) are rarely used as fibrous reinforcing materials due to their cost limitations, and molded products with high impact strength that are mainly blended with vinylon fibers. At present, there is no phenolic resin molding material that can provide this. In view of the problems of the above-mentioned prior art, the present inventors
First, we developed a phenolic resin molding material for injection molding (Tokugan Akira).
58-160407). This is a phenol for injection molding that gives high impact strength and is made by blending vinylon fiber with a phenolic resin with selected solubility parameters (according to "Adhesion Encyclopedia (Part 1)" written by Ichiro Shibasaki, published by Kobunshi Publishing Co., Ltd., 1951, p. 33). It concerns resin molding materials and was based on the discovery that the tensile strength of fibers and the impact strength of molded products are uniquely related, and that the solubility parameter of phenolic resin is uniquely related to the solubility of vinylon fiber. It is something that However, the phenolic resin molding material for injection molding according to the above-mentioned earlier application has a small apparent density (according to JISK6911), that is, a large volume (according to JISK6911) of the molding material. Although a molded product with high strength can be obtained, the molding material tends to form a bridge structure in the hopper of the injection molding machine, making it difficult to remove the material, making continuous molding somewhat difficult, and the impact value also varies. I found out that there was a problem. In addition, the minimum baking time during molding is slightly longer, resulting in a longer molding cycle, and the residence time range (hereinafter abbreviated as residence time) that enables stable long-term injection molding within the cylinder of an injection molding machine is also shortened. The appearance of the obtained molded product is not completely good, and therefore, the molding material according to the previous application is not suitable for molded products with relatively large sprues or runner diameters. It was highly effective. In view of the problems of the molding material related to the previous application, the present inventors conducted further intensive research and found that
The apparent density of the phenolic resin molding material is more than double that of the molding material related to the previous application, that is, the volume of the molding material is reduced to 1/2 or less, so that continuous injection molding can be performed stably, and the resulting molding We have discovered new factors that can improve moldability and Shapey impact strength, such as the fact that the Shapey impact strength of the product is always 2 to 3 kgf cm/cm ² better than commercially available phenolic resin molding materials, and we have also discovered new factors that can improve moldability and Shapey impact strength. It was also confirmed that an excellent molded product with high Charpy impact strength and good appearance can be obtained by compression molding, and the present invention was completed. [Object of the Invention] An object of the present invention is to provide a phenolic resin molding material that has good moldability, such as stable continuous molding, and can yield molded products with high Shapey impact strength. [Structure and operation of the invention] The phenolic resin molding material of the present invention was made to achieve the above object, and its structure consists of a phenolic resin 100% having a solubility parameter of 9.0 to 11.0.
It is characterized by containing 5 to 150 parts by weight of polyvinyl alcohol fibers having a tensile strength of 6 g/denier or more and 2 to 50 parts by weight of a lubricating filler. Here, the present inventors will explain the action of the lubricating filler, which is one of the constituent factors of the present invention.
We discovered the surprising phenomenon that when a lubricating filler is added to 11.0 phenolic resin, the shear peace impact strength does not decrease even during continuous injection molding. This seems to be because the lubricating filler allows the material to slide smoothly and minimizes the heat generated by friction.
Local heat generation of the material is suppressed in particularly high-temperature areas such as sprues and runners in the injection molding machine cylinder or mold, or in the Henschel mixer during material production, and the tensile strength of the vinylon fiber is maintained sufficiently. It is believed that a molding material that provides molded products with high impact strength can be obtained. Furthermore, adding a lubricating filler improves heat conduction when the molding material is filled into the mold, and has the effect of shortening the minimum baking time. Other lubricating fillers have the effect of improving the slipperiness, ie, fluidity, of the molding material within the cylinder of the injection molding machine, and increasing the residence time of the molding material in order to suppress heat generation due to friction. The vinylon fiber used in the present invention must have a tensile strength of 6 g/denier or more, more preferably 7.5 g/denier or more. tensile strength
If it is less than 6 g/denier, a molded article with high impact strength cannot be obtained even if a large amount of vinylon fiber is used. There is no particular limitation on the fiber length, but commonly used fibers of 1 to 6 mm can be suitably used. The vinylon fiber is preferably used in an amount of 5 to 150 parts by weight per 100 parts by weight of the phenol resin. When used for injection molding, the amount of fiber is preferably 5 to 100 parts by weight, more preferably
It is 30-70 parts by weight. When used for transfer molding or compression molding, the amount of fiber is preferably 5 to 150 parts by weight, more preferably
It is 30-110 parts by weight. If the amount of vinylon fiber used is less than the lower limit of the above range, the intended improvement in the shear py impact strength will be substantially smaller, and conversely, if the amount of vinylon fiber used is more than the upper limit of the range, the shar py impact strength will be even higher. However,
This is not preferable because it becomes a material that is difficult to mold. In addition, in the present invention, in addition to vinylon fiber, in consideration of heat resistance, bending strength, tensile strength, etc., organic and inorganic fillers such as cellulose and glass fiber, which are usually used in phenolic resin molding materials, are used in combination. is valid. As the lubricating filler used in the present invention, graphite, molybdenum disulfide, tungsten disulfide, etc. are preferably used, and these can be used alone or in the form of any mixture. Among them, graphite and molybdenum disulfide are more preferable. The amount of the lubricating filler is 2 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the phenolic resin. If the amount is less than 2 parts by weight, the minimum baking time during injection molding will not be shortened, and the lubricating effect will not be achieved, resulting in a large amount of heat generation in the cylinder, resulting in a molding material with poor residence time, etc. There is no substantial improvement in sexual performance. On the other hand, if the amount is more than 50 parts by weight, the proportion of vinylon fibers in the molding material decreases, making it impossible to obtain a molded product with high shear pea impact strength, which is not preferable. The solubility parameter used in the present invention is 9.0
Examples of phenolic resins in the range of ~11.0 include benzyl ether type phenolic resin, ammonia resol type phenolic resin, and bisphenol A.
Preferred examples include modified phenolic resins, aniline-modified phenolic resins, and amine-modified phenolic resins. These resins may be either novolac type or resol type, and can be used alone or in combination. The phenolic resin molding material of the present invention can be produced by a conventional method. For example, 100 parts by weight of a phenolic resin with a solubility parameter in the range of 9.0 to 11.0, 5 to 150 parts by weight of vinylon fiber having a tensile strength of 6 g/denier or more, 2 to 50 parts by weight of a lubricating filler, and Appropriate amounts of organic and inorganic base materials such as cellulose and glass fiber, as well as additives such as curing agents, curing catalysts, mold release agents, and coloring agents, are blended and uniformly dispersed and mixed in a Henschel mixer with an appropriate amount of solvent. By further kneading and granulating while heating and stirring at high speed, a granular phenolic resin molding material having a volume of 30 to 40 c.c./20 g and a diameter of 2 to 20 mm can be produced. [Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but it goes without saying that the technical scope of the present invention is not limited to these Examples. [Example 1] Part by weight Benzylic ether type phenolic resin vinylon fiber 100 (Tensile strength 6.0 g/denier, 1 mm cut product) 50 Graphite 20 Wood powder 30 Calcium hydroxide 10 Stearic acid 5 Methanol 80 The above mixture was mixed into Henschel The mixture was uniformly dispersed and mixed in a mixer, and further kneaded under heating and high-speed stirring to obtain a granular phenolic resin molding material. The apparent density of the obtained molding material (measured according to JISK6911) is
The volume of the molding material is 0.61 g/cc, which is more than twice as large as the phenolic resin molding material for injection molding according to the earlier application, and the volume of the molding material is 33 c.c./20 g, which is less than half of the molding material according to the earlier application. It was hot. Moreover, the spiral flow value was 380 mm. This molding material is used in an injection molding machine under the general molding conditions (injection molding pressure 1200 to 1500).
Hollow boxes and hollow breakers were injection molded at a temperature of 160-170° C. (Kg/cm ² and a mold temperature of 160-170° C.), and their minimum baking time and residence time were measured. In addition, in this specification, "minimum baking time" refers to dimensions 99 x 32
×29mm, 2mm thick hollow box and dimensions 88×45
When simultaneously injection molding hollow breakers with a diameter of 19 mm and a thickness of 4 mm in the same mold, the material was completely injected into the mold, the mold was heated and pressed, and when the mold was opened and the molded product was taken out, the molded product The minimum heating and pressurizing time after injection and filling until no gas blisters are seen at the gate. As a result of the test, the minimum baking time was that of the earlier application.
80 seconds, while the molding material of the present invention had a heating time of 35 seconds.
The residence time was reduced to 3 seconds, compared to about 1 minute in the previous application. Further, injection molding was performed using this molding material under the above conditions to obtain a JIS test piece for measuring Charpy impact strength. As a result of the test, the Charpy impact strength of this test piece was 7.5 Kgf·cm/cm ² . Further, other physical properties were as shown in Table 1. Note that the physical properties were measured based on JISK6911. [Example 2] In Example 1, the blending amount of graphite was increased to 40
A molding material was obtained in the same manner as in Example 1, except that the amount of wood flour was changed to 10 parts by weight. The apparent density of the obtained molding material was 0.59g/
cc, volume was 34c.c./20g, and spiral flow value was 410mm. Using this molding material, injection molding was carried out in the same manner as in Example 1, the minimum baking time and residence time were measured, and JIS test pieces for Charpy impact strength were obtained. As a result, the minimum baking time was 33 seconds and the residence time was 3 minutes. Further, the Charpy impact strength of the test piece was 7.1 Kgf·cm/cm ² , and other physical properties were as shown in Table 1. [Example 3] In Example 1, the blending amount of graphite was 5
A molding material was obtained in the same manner as in Example 1, except that the amount of wood flour was changed to 45 parts by weight. The apparent density of the obtained molding material was 0.56g/
cc, volume was 36c.c./20g, and spiral flow value was 400mm. Using this molding material, injection molding was carried out in the same manner as in Example 1, the minimum baking time and residence time were measured, and JIS test pieces for Charpy impact strength were obtained. As a result, the minimum baking time was 45 seconds and the residence time was 2 minutes. Further, the Charpy impact strength of the test piece was 6.3 Kgf·cm/cm ² , and other physical properties were as shown in Table 1. [Example 4] In Example 1, the blending amount of vinylon fiber was changed to 30
A molding material was obtained in the same manner as in Example 1, except that the amount of wood flour was changed to 50 parts by weight. The apparent density of the obtained molding material was 0.63g/
cc, volume was 32c.c./20g, and spiral flow value was 360mm. Using this molding material, injection molding was carried out in the same manner as in Example 1, the minimum baking time and residence time were measured, and JIS test pieces for Charpy impact strength were obtained. As a result, the minimum baking time was 33 seconds and the residence time was 3 minutes. Further, the Charpy impact strength of the test piece was 5.3 Kgf·cm/cm ² , and other physical properties were as shown in Table 1. [Example 5] In Example 1, the blending amount of vinylon fiber was increased to 70%.
Except for changing the parts by weight and not adding wood flour,
A molding material was obtained in the same manner as in Example 1. The apparent density of the obtained molding material was 0.50g/cc, and the volume was
40c.c./20g, and spiral flow value is 430mm
It was hot. Using this molding material, injection molding was carried out in the same manner as in Example 1, the minimum baking time and residence time were measured, and JIS test pieces for Charpy impact strength were obtained. As a result, the minimum baking time was 38 seconds and the residence time was 2 minutes. Further, the Charpy impact strength of the test piece was 85 Kgf·cm/cm ² , and other physical properties were as shown in Table 1. [Example 6] A molding material was obtained in the same manner as in Example 1 except that molybdenum disulfide was used instead of graphite. The resulting molding material had an apparent density of 0.61 g/cc, a volume of 33 c.c./20 g, and a spiral flow value of 370 mm. Using this molding material, injection molding was performed in the same manner as in Example 1, and the minimum baking time and residence time were measured.
In addition, JIS test pieces for Shapey impact strength were obtained. As a result, the minimum baking time was 34 seconds and the residence time was 3 minutes. Further, the Charpy impact strength of the test piece was 7.3 Kgf·cm/cm ² , and other physical properties were as shown in Table 1. [Example 7] Part by weight Aniline modified phenolic resin 100 Vinylon fiber (tensile strength 6.0 g/denier, 1 mm
Cut products) 50 Graphite 20 Wood flour 30 Hexamethylenetetramine 20 Magnesium oxide 10 Stearic acid 5 Methanol 80 A molding material was obtained using the above blend in the same manner as in Example 1. The apparent density of the obtained molding material was 0.59g/
cc, volume was 34c.c./20g, and spiral flow value was 390mm. Using this molding material, injection molding was performed in the same manner as in Example 1, and the minimum baking time and residence time were measured.
In addition, JIS test pieces for Shapey impact strength were obtained. As a result, the minimum baking time was 48 seconds, the residence time was 3 minutes, and the Charpy impact strength of the test piece was 7.2 Kgf·cm/cm ² . Other physical properties were as shown in Table 1. [Example 8] Weight part Benzyl ether type phenolic resin 100 Vinylon fiber (tensile strength 6.0 g/denier, 1 mm
Cut products) 80 Graphite 20 Calcium hydroxide 10 Stearic acid 5 Methanol 80 The above mixture was uniformly dispersed and mixed in a Henschel mixer, and further kneaded under heating and high speed stirring to obtain a granular phenolic resin molding material. The spiral flow value of the molding material obtained was 430 mm. Using this molding material, 160℃, 400Kg/cm ² and 5
Transfer molding was performed under conditions of 1 minute to obtain JIS test pieces for measuring Shapey impact strength. As a result of the test, the Shapey impact strength of this test piece was 11.5
It was Kgf・cm/ ^cm2 . Other physical properties were as shown in Table 1. [Example 9] Part by weight Benzyl ether type phenolic resin 100 Vinylon fiber (tensile strength 6.0 g/denier, 1 mm cut product) 100 Graphite 20 Calcium hydroxide 10 Stearic acid 5 Methanol 80 The above mixture was mixed in a Henschel mixer. The mixture was uniformly dispersed and mixed, and further kneaded while heating and stirring at high speed to obtain a granular phenolic resin molding material. The spiral flow value of the molding material obtained was 310 mm. Using this molding material, 160℃, 200Kg/cm ² and 5
Compression molding was carried out under conditions of 1 minute to obtain JIS test pieces for measuring Shapey impact strength. As a result of the test, the Shapey impact strength of this test piece was 13.7Kgf・cm/
It was warm in ^cm2 . Other physical properties were as shown in Table 1. [Comparative Example 1] A molding material was obtained in the same manner as in Example 1 except that the amount of wood flour blended was changed to 50 parts by weight and graphite was not blended. The apparent density of the molding material obtained was 0.63 g/cc, the volume was 32 c.c./20 g, and the spiral flow value was 380 mm. Using this molding material, injection molding was carried out in the same manner as in Example 1, the minimum baking time and residence time were measured, and JIS test pieces for measuring Charpy impact strength were obtained. As a result, the minimum baking time was 78 seconds and the residence time was about 1 minute. Further, the Charpy impact strength of the test piece was 4.3 Kgf·cm/cm ² , and other physical properties were as shown in Table 1. [Comparative Example 2] A molding material was obtained in the same manner as in Example 1, except that the amount of graphite blended in Example 1 was changed to 60 parts by weight, and wood flour was not blended. The apparent density of the obtained molding material was 0.59 g/cc, and the volume was 34
cc/20g, and the spiral flow value was 360mm. Using this molding material, injection molding was carried out in the same manner as in Example 1, the minimum baking time and residence time were measured, and JIS test pieces for measuring Charpy impact strength were obtained. As a result, the minimum baking time was 32 seconds and the residence time was 3 minutes. Further, the Charpy impact strength of the test piece was 4.6 Kgf·cm/cm ² , and other physical properties were as shown in Table 1. [Comparative Example 3] A molding material was prepared in the same manner as in Example 1, except that instead of the vinylon fiber with a tensile strength of 6.0 g/denier in Example 1, vinylon fiber with a tensile strength of 3.5 g/denier and a 1 mm cut product was used. I got it. The resulting molding material had an apparent density of 0.63 g/cc, a volume of 32 c.c./20 g, and a spiral flow value of 410 mm. Using this molding material, injection molding was carried out in the same manner as in Example 1, the minimum baking time and residence time were measured, and JIS test pieces for measuring Charpy impact strength were obtained. As a result, the minimum baking time was 36 seconds and the residence time was 3 minutes. The test piece had a Charpy impact strength of 4.1 Kgf·cm/cm ² . Other physical properties were as shown in Table 1. [Comparative Example 4] In Example 8, a 1 mm cut vinylon fiber with a tensile strength of 3.5 g/denier was used instead of the vinylon fiber with a tensile strength of 6.0 g/denier, and graphite was not blended. A molding material was obtained in the same manner as in Example 8. The spiral flow value of the molding material obtained was 400 mm. Using this molding material, transfer molding was performed in the same manner as in Example 8 to obtain a JIS test piece for measuring Shapey impact strength. As a result of the test, the Charpy impact strength of this test piece was 3.7 Kgf·/cm/cm ² . Other physical properties were as shown in Table 1. [Comparative Example 5] Novolac type phenolic resin ( parts by weight ) 100 Hexamethylenetetramine 20 Vinylon fiber (tensile strength 3.5 g/denier, 1 mm cut product) 50 Wood flour 30 Magnesium oxide 10 Stearic acid 5 Methanol 80 The above formulation was used as Example 9. A phenolic resin molding material was obtained by mixing and kneading in the same manner. The spiral flow value of the molding material obtained was 290 mm. Compression molding was performed using this molding material in the same manner as in Example 9 to obtain a JIS test piece for measuring Charpy impact strength. As a result of the test, the Charpy impact strength of this test piece was 3.9 Kgf·cm/cm ² . Other physical properties were as shown in Table 1.

〔Effect of the invention〕

The phenolic resin molding material of the present invention has the following effects compared to the phenolic resin molding material for injection molding of the earlier application. 1 The apparent density has more than doubled, meaning the volume of the molding material has been reduced to less than half, so the material falls out easily in the popper of the injection molding machine and has good lubricity. Therefore, the moldability is very stable, and a phenolic resin molding material with a high impact strength that is always superior to commercially available products by 2 to 3 Kgf·cm/cm ² in Charpy impact strength can be obtained by continuous molding. 2 Minimum baking time during injection molding ranges from 60 to 80 seconds to 30 seconds
~50 seconds, which is about 1/2 or less, and the molding cycle can be shortened. 3. The thermal stability, that is, the residence time in the cylinder is from about 1 minute to about 3 minutes, and the moldability is good. 4. Beautiful and good-quality molded products with a glossy appearance can be obtained. In addition, moldability is improved in transfer molding and compression molding, and molded products with high Shapey impact strength can be obtained. In addition, it has excellent sliding properties and abrasion resistance that cannot be obtained with glass fiber reinforced materials, and has the advantage that a lightweight molded product can be obtained because the material itself has a low specific gravity.

Claims (1)

[Scope of Claims] 1. Polyvinyl alcohol fibers having a tensile strength of 6 g/denier or more based on 100 parts by weight of a phenolic resin having a solubility parameter of 9.0 to 11.0.
A phenolic resin molding material comprising 150 parts by weight and 2 to 50 parts by weight of a lubricating filler. 2. The phenolic resin molding material according to claim 1, wherein the lubricating filler is graphite, molybdenum disulfide, or tungsten disulfide. 3. The phenolic resin molding material according to claim 1 or 2, wherein the phenolic resin is a benzyl ether type phenolic resin or an ammonia aresol type phenolic resin. 4. The phenolic resin molding material according to claim 1 or 2, wherein the phenolic resin is a bisphenol A-modified phenolic resin, an aniline-modified phenolic resin, or an amine-modified phenolic resin.