JP4187806B2 - Method for producing granular thermosetting resin molding material - Google Patents

Description

BACKGROUND OF THE INVENTION
[0001]
The present invention relates to a granular thermosetting resin molding material. In particular, the present invention relates to a granular thermosetting resin molding material that generates less dust, has excellent meterability, and has excellent molding processability such as injection molding, and a manufacturing method thereof.
[Prior art]
[0002]
Thermosetting resins, such as phenolic resin molding materials, are excellent in properties such as mechanical strength, electrical properties, heat resistance, etc., and have been conventionally used in the fields of automobiles, electricity, machinery, or general molded products. Used for resin products in a wide range of industrial fields. The phenolic resin molding material (thermosetting resin molding material) used as a raw material for such products is made of raw material resin, reinforcing material such as glass fiber, carbon fiber, wood powder, cloth chip, filler, curing agent. , Manufactured by mixing a mixture containing a release agent, a colorant, etc., kneading with a kneading apparatus such as a kneading roll, kneader or screw extruder, and pulverizing or pelletizing the kneaded product It is.
[0003]
As a method for producing such a phenolic resin molding material, a kneaded product obtained by kneading the above compound is extruded from a die attached to an extruder, and the extruded strand is cut into a predetermined length by a cutter. However, an extrusion granulation method for forming a granular material is known. For example, Japanese Patent Laid-Open No. 3-246011 proposes a method for producing a phenol-based resin molding material in which materials containing a thermosetting resin and glass fiber as main blending components are mixed and extruded and granulated with an extruder. Yes. Japanese Patent Laid-Open No. 6-192435 proposes a method for producing a phenolic resin molding material in which water is added to a phenolic resin molding material composition containing glass fiber as an essential component, kneaded, and extrusion granulated. . In JP-A-7-80829 and JP-A-7-80830, an extruder having a specific L / D after adding a chopped strand glass fiber of a specific length and a solvent to a phenol resin, kneading with a high-speed mixer A method for producing a phenolic resin molding material by extrusion granulation has been proposed.
In the extrusion granulation method as described above, a strand extruded from a die attached to an extruder is cut into a predetermined length with a cutter to form a granular material. However, since the target is a thermosetting resin material, the extruder die is likely to be clogged. And since it is intended for thermosetting resins, once clogging occurs, the recovery operation is very troublesome and productivity is poor. Furthermore, shredding is likely to occur in glass fibers and the like, resulting in a decrease in physical properties of the molded product.
[0004]
In addition, a granulation method is known in which the above-mentioned compound is granulated with a high-speed stirring mixer such as a Henschel mixer. For example, in JP-A-2-169206, a phenolic resin that is granulated with a high-speed stirring mixer by adding a low-boiling solvent having a boiling point of 100 ° C. or lower to a phenolic resin molding material kneaded and pulverized by a mixing roll or an extrusion kneader. A method for producing a molding material has been proposed.
However, granulation with a high-speed stirring mixer such as a Henschel mixer tends to shatter glass fibers and the like, which adversely affects physical properties such as a decrease in mechanical strength. There is also a problem that fine powder is easily attached.
[0005]
Further, the above-mentioned compound is kneaded with a pressure kneader or the like under heating, and is formed into a sheet or strand, dried, pulverized with a pulverizer, and sieved to obtain a granular material. There is also a method.
However, this method means that the shapes of the obtained particles are not uniform. This means that in the case of injection molding or the like, the meterability is poor, which causes a serious problem in molding processability. Note that if the sieving is strictly performed in order to make the shape of the granular material uniform, the productivity is extremely lowered.
Further, the above method has a problem that when the sheet is pulverized into a granular material, fine powder is generated and easily adheres to the surface of the granular material. If this fine powder is mixed, since the melting temperature differs greatly between the granular material and the fine powder when molding using this, the quality of the molded product is greatly deteriorated, which is not preferable. And generation | occurrence | production of fine powder causes environmental pollution, and also reduces productivity. Furthermore, there is a possibility that fine powder will be scattered during use, which is undesirable in handling.
[Problems to be solved by the invention]
[0006]
Therefore, the problem to be solved by the present invention is to solve the problems of the above-described conventional technology.
[0007]
That is, the first problem to be solved by the present invention is to provide a technique capable of producing granular thermosetting resin molding materials such as phenolic resin molding materials and unsaturated polyester resin molding materials without using an extruder. That is. That is, it is to provide a technique that does not cause the problem of die clogging and is difficult to cause the problem of productivity and the problem that the physical properties of the molded product are deteriorated because the glass fiber is shredded.
[0008]
The second problem to be solved by the present invention is to provide a technique capable of producing a granular thermosetting resin molding material without using a high-speed stirring mixer such as a Henschel mixer. That is, it is not necessary to use a high-speed agitation mixer such as a Henschel mixer, and therefore, it is to provide a technique in which glass fibers and the like are not easily shredded and problems such as deterioration of physical properties of a molded product hardly occur.
[0009]
The third problem to be solved by the present invention is to provide a technique capable of producing a granular thermosetting resin molding material without using a pulverizer. That is, since the pulverizer is not used, the shape of the obtained particles is uniform, and therefore, the meterability is good, the moldability is good, the productivity is good, and the fine powder is not easily generated. Providing a granular thermosetting resin molding material suitable as an injection molding material that is less likely to mix due to adhesion to the surface of the object, hardly deteriorates in the quality of the molded product, and also improves the risk of deterioration in molding processability It is to be.
[Means for Solving the Problems]
[0010]
In order to solve the above-mentioned problems, the present inventor has made various studies on a method for producing a granular thermosetting resin molding material with less generation of dust. As a result, the conventional high-speed stirring mixer and extrusion granulation method are completely different from each other, but an extremely simple method has been realized. Moreover, according to this method, a granular thermosetting resin molding material having a uniform shape and generating less dust can be obtained.
[0011]
That is, the above-mentioned problems include a kneading step of adding glass fiber , filler, curing agent, mold release agent, and colorant to a phenolic resin or unsaturated polyester resin , and mixing and kneading.
The kneaded product obtained in the kneading step is made into a sheet-like product having a thickness of 1 to 5 mm by a heating roll ,
The sheet-like material obtained in the sheet forming step is controlled to a temperature of 45 to 55 ° C., and the temperature-controlled sheet material is 1 to 5 mm wide by a cutting blade controlled to a temperature of 30 ° C. or less. A cutting process of cutting into objects,
The string-like material obtained in the cutting step is controlled to a temperature of 45 to 55 ° C, and the temperature-controlled string-like material is formed into a granular material having a length of 1 to 5 mm by a cutting blade controlled to a temperature of 30 ° C or less. It solves by the manufacturing method of the granular thermosetting resin molding material characterized by comprising the cutting process cut | disconnected.
[0013]
The present invention eliminates the need to use a high-speed agitating mixer or crusher such as an extruder or a Henschel mixer, and therefore, various kinds of problems that have occurred in the production of granular thermosetting resin molding materials using these apparatuses. The problem is solved. That is, the problem of die clogging, the problem of lowering the productivity, and the problem of lowering the physical properties of the molded product due to glass fiber shredding are improved. Furthermore, the problem of generation of fine powder is unlikely to occur, and deterioration of molding processability and quality of molded products due to variations in melting temperature during molding that occurs when fine powder is mixed in the granular thermosetting resin molding material. The problem is improved.
Furthermore, since it is only made into a sheet by, for example, a heating roll and then cut and cut, it can be obtained very easily.
[0015]
Moreover, the said subject is solved by the granular thermosetting resin molding material characterized by being obtained by the manufacturing method of the said granular thermosetting resin molding material.
DETAILED DESCRIPTION OF THE INVENTION
[0016]
The method for producing a granular thermosetting resin molding material of the present invention is obtained by a kneading step of adding a filler, a reinforcing agent, a curing agent, and other additives to a thermosetting resin, mixing and kneading, and the kneading step. The kneaded product into a sheet-like material, a cutting step for cutting the sheet-like material obtained in the sheet-forming step into a string-like material, and the string-like material obtained in the cutting step with a predetermined length And a cutting step of cutting into a granular material. The temperature of the sheet-like material in the cutting process is controlled to 25 to 100 ° C. The temperature of the cutting blade is controlled to a temperature of 85 ° C. or lower. The temperature of the string-like object in the cutting step is controlled to 25 to 100 ° C. The temperature of the cutting blade is controlled to a temperature of 85 ° C. or lower. The sheet-like material has a thickness of 1 to 5 mm, a cutting width of 1 to 5 mm, and a cutting length of 1 to 5 mm. In particular, after adding a filler, reinforcing agent, curing agent, and other additives to the thermosetting resin, mixing and kneading, the kneaded product is sheeted to a thickness of 1 to 5 mm, and the sheet is 1 to 5 mm in width. This is a method of cutting the string-like material into a length of 1 to 5 mm. Further, a filler, a reinforcing agent, a curing agent, and other additives are added to the thermosetting resin, mixed and kneaded, and then formed into a sheet shape having a thickness of 1 to 5 mm with a heating roll, and the sheet has a width of 1 to 5 mm. This is a method of cutting into a string shape and cutting it to a length of 1 to 5 mm in a direction perpendicular to the longitudinal direction of the string-like object. In addition, a filler, a reinforcing agent, a curing agent, and other additives are added to and mixed with powdered or liquid phenolic resin or unsaturated polyester resin, kneaded, and then sheeted to a thickness of 1 to 5 mm. In this method, the sheet is cut into a string having a width of 1 to 5 mm, and the string is cut into a length of 1 to 5 mm. In addition, fillers, reinforcing agents, curing agents, and other additives are added to and mixed with thermosetting resins such as powdered or liquid phenolic resins or unsaturated polyester resins, and after kneading, 1-5 mm with a heating roll. The sheet is formed into a thickness, and the sheet is continuously cut into a string having a width of 1 to 5 mm by a cutting device equipped with a rotary blade, and the length is 1 to 5 mm in a direction perpendicular to the longitudinal direction of the string. It is a method of cutting.
[0017]
This will be described in detail below.
In the present invention, when cutting or cutting a sheet-like material, it is preferable to cut or cut the sheet-like material by controlling the temperature of the sheet-like material and the temperature of the cutting blade or the cutting blade within a certain temperature range. The temperature of the sheet-like material at this time is set depending on the properties of the resin used, the reinforcing material, the filler, and the type and amount of other additives, but generally room temperature (usually about 25 ° C.) It is preferable to be set in a range of ˜100 ° C. More preferably, it is 45-55 degreeC. In general, the temperature of the cutting blade or the cutting blade is preferably set to a temperature of 85 ° C. or lower. More preferably, the temperature is 30 ° C. or lower. That is, if the temperature of the sheet-like material is too lower than the above temperature range, a large amount of fine powder is likely to be generated at the time of cutting or cutting, and conversely, if it is too high, the sheet tends to adhere to the cutting blade or cutting blade. Good cutting / cutting is difficult. In addition, there is a possibility that the objects after cutting and cutting adhere to each other, and the productivity is lowered. When the temperature of the cutting blade or the cutting blade is too higher than the above temperature range, the sheet is likely to adhere to the cutting blade or the cutting blade, and it is difficult to perform good cutting, and productivity is lowered.
[0018]
In addition, the rectangular granular material obtained by cutting and cutting the sheet-like material of the present invention may be processed by a granulator such as a Malmerizer. In such a case, the sharp corners of the square shape are slightly rounded, the workability and the meterability are improved, and the generation of fine powder during handling is suppressed.
[0019]
The shape of the granular thermosetting resin molding material of the present invention is generally a rectangular parallelepiped having a thickness of 1 to 5 mm, a width of 1 to 5 mm, and a length of 1 to 5 mm. This thing is excellent in the meterability in injection molding. More preferably, the thickness is 2 to 3 mm, the width is 2 to 3 mm, and the length is 2 to 3 mm. That is, in such a case, more stable weighing can be performed, and continuous injection molding can be performed more efficiently. In order to bring the shape of the granular thermosetting resin molding material into the above range, it is possible to adjust the shape of the cutting blade and the cutting blade, the interval between the cutting blade and the cutting blade, the cutting / cutting temperature, and the like.
[0020]
Examples of the thermosetting resin in the present invention include novolak-type or resol-type phenolic resins, unsaturated polyester resins, and diaryl phthalate resins. These resins are synthetic resins used for molding materials and are used in solid or liquid form, but they are solid resins with good dispersibility when mixed with other fillers, reinforcing materials and other additives. A shape (powder) is preferred.
The apparatus provided with the cutting blade and the cutting blade used in the present invention can use an apparatus capable of continuously cutting and cutting a sheet. For example, an apparatus such as a commercially available sheet pelletizer equipped with a rotary blade is used.
Hereinafter, the present invention will be specifically described by way of examples. “Parts” represents parts by weight.
【Example】
[0021]
[Example 1]
Glass fiber 100 parts powdery phenolic resin (fiber length: 6 mm, diameter: 13μ m) 70 parts, 70 parts of calcium carbonate, a curing agent (hexamethylene tetramine) 15 parts, other additives (release agents, coloring agents) Was blended in a desired amount, kneaded under heating with a kneader, and a sheet having a thickness of 3 mm and a width of 300 mm was produced with a heating roll at 50 ° C.
The sheet was cut into a 3 mm wide string with a disk-shaped rotary blade with a sheet temperature of 55 ° C. and a blade interval of 3 mm. The string-like material was cut to a length of 3 mm with a rotary cutter. The cutting blade and the blade of the rotary cutter were controlled at 25 ° C.
The phenol resin molding material thus produced was a rectangular parallelepiped shape having a length of 3 mm, a width of 3 mm, and a height of 3 mm. The granular phenolic resin molding material was easy to handle with little generation of fine powder, there was almost no variation in measurement during injection molding, and the molding processability was good, and a good molded product was obtained.
[0022]
[Example 2]
In Example 1, the sheet temperature was set to 53 ° C., the blade interval was set to 4 mm, and cut into a 4 mm wide string, and the string was cut into a length of 5 mm with a rotary cutter, and 3 mm × 4 mm × 5 mm. A rectangular resin-shaped phenolic resin molding material was obtained.
This granular phenolic resin molding material is easy to handle with little generation of fine powder, has almost no variation in measurement at the time of injection molding, and has good molding processability, and a good molded product was obtained.
[0023]
[Example 3]
100 parts of unsaturated polyester resin, 80 parts of glass fiber, 150 parts of filler (calcium carbonate), 30 parts of diallyl phthalate prepolymer, and other additives are blended and mixed, kneaded under heating, and 50 ° C. A sheet having a thickness of 3 mm and a width of 300 mm was produced with a heating roll.
The sheet was cut into a 3 mm wide string with a disk-shaped rotary blade with a sheet temperature of 52 ° C. and a blade interval of 3 mm. Then, the string-like material was cut into a length of 3 mm with a rotary cutter. The cutting blade and the blade of the rotary cutter were controlled at 25 ° C.
The unsaturated polyester resin molding material produced in this way was a rectangular parallelepiped shape having a length of 3 mm, a width of 3 mm, and a height of 3 mm. And this granular unsaturated polyester resin molding material is easy to handle with little generation of fine powder, there is almost no measurement variation at the time of injection molding, and the molding processability is good, and a good molded product was obtained. .
[0024]
[Comparative Example 1]
The same formulation as in Example 1 was kneaded to obtain a sheet. The sheet was cooled to room temperature, and then pulverized with an impact pulverizer equipped with a 3 mm screen to obtain a granular phenol resin molding material.
The granular phenolic resin molding material obtained in this way has a large amount of fine powder generated during handling, is difficult to handle, has a large measurement variation during injection molding, and cannot be molded satisfactorily.
[0025]
[Comparative Example 2]
The same formulation as in Example 3 was kneaded to obtain a sheet. The sheet was cooled to room temperature, and then pulverized with an impact pulverizer equipped with a 3 mm screen to obtain an unsaturated polyester resin molding material.
The unsaturated polyester resin molding material obtained in this manner has a large amount of fine powder generated during handling, is difficult to handle, has a large measurement variation during injection molding, and cannot be molded satisfactorily.
【The invention's effect】
[0026]
The granular thermosetting resin molding material of the present invention is hardly accompanied by generation of dust, has good productivity, and is easy to handle. The granular material has a uniform shape and good meterability, and is a molding material suitable as an injection molding material.

Claims (1)

A kneading step of adding glass fiber , filler, curing agent, mold release agent, colorant to the phenolic resin or unsaturated polyester resin , and mixing and kneading;
The kneaded product obtained in the kneading step is made into a sheet-like product having a thickness of 1 to 5 mm by a heating roll ,
The sheet-like material obtained in the sheet forming step is controlled to a temperature of 45 to 55 ° C., and the temperature-controlled sheet material is 1 to 5 mm wide by a cutting blade controlled to a temperature of 30 ° C. or less. A cutting process for cutting into objects,
The string-like material obtained in the cutting step is controlled to a temperature of 45 to 55 ° C, and the temperature-controlled string-like material is formed into a granular material having a length of 1 to 5 mm by a cutting blade controlled to a temperature of 30 ° C or less. The manufacturing method of the granular thermosetting resin molding material characterized by including the cutting process cut | disconnected.