JP3107348B2 - Molding method for resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a resin molded article in which a thermosetting resin mixed with a crosslinking agent is molded by heating and pressing with a mold.

[0002]

2. Description of the Related Art Conventionally, a thermosetting resin mixed with a crosslinking agent has been heated and pressed using a mold.
There are dents and burning. Therefore, it has been proposed to provide a vacuum deaerator in a mold and perform vacuum deaeration at the time of molding.
It is disclosed in Japanese Patent Publication No. 2-50370. However,
When the styrene gas is degassed by vacuum degassing, there is a problem that the ratio of the crosslinking agent to the thermosetting resin decreases, and the performance of the formed resin molded product decreases. For example, there is a problem that a whitening phenomenon occurs in an immersion test in a hot water environment.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object the following.
It is an object of the present invention to provide a method for molding a resin molded article in which the ratio of the crosslinking agent to the thermosetting resin does not decrease even when vacuum degassing is performed, and the performance of the formed resin molded article does not decrease.

[0004]

In order to solve the above-mentioned problems of the prior art and achieve the object of the present invention, a method of molding a resin molded product of the present invention comprises a method of forming a thermosetting resin mixed with a crosslinking agent. In the method of molding a resin molded article obtained by heating and pressing with the mold 2 to obtain a resin molded article, after the thermosetting resin is disposed in the mold 2, the vacuum in the cavity 3 is performed in the process of closing the mold 2. The method is characterized in that the same amount as the amount of the cross-linking agent volatilized by degassing is compensated in advance and molding is performed.

In a method of molding a resin molded article by heating and pressing a thermosetting resin mixed with a crosslinking agent by a mold 2 to obtain a resin molded article, the method comprises the steps of: disposing the thermosetting resin in the mold 2; In the process of closing and closing the mold 2 ,
Close the mold while performing vacuum degassing and continuing this vacuum degassing.
During the process, the cavity 3 is filled with the gas of the crosslinking agent ,
It is also preferable to perform molding by heating and pressing after the mold is closed . Further, in a method for molding a resin molded product in which a thermosetting resin mixed with a crosslinking agent is heated and pressed by a mold 2 to obtain a resin molded product, after disposing the thermosetting resin in the mold 2, The gas concentration of the cross-linking agent in the gas that is vacuum-degassed from inside the cavity 3 during the closing process of the mold 2 is measured, and when the measured value of the gas concentration of the cross-linking agent becomes a predetermined value or more, the vacuum degassing is performed. It is also preferable to stop and carry out molding.

[0006]

According to the method of the present invention as described above, after the thermosetting resin mixed with the crosslinking agent is placed in the mold 2, the mold 2
In this process, the same amount as the amount of the cross-linking agent volatilized by the vacuum degassing in the cavity 3 performed in the closing process is supplemented in advance, and molding is performed. The amount of the cross-linking agent can be maintained at a predetermined amount or more.

After the thermosetting resin is placed in the mold 2,
Vacuum deaeration in the cavity 3 during the closing process of the mold 2
The fill the cross-linking agent in the gas into the <br/> cavity 3 in the process closing the mold continues to the vacuum degassing performs, after the mold closing
In the case of molding by heating and pressing, the amount of the cross-linking agent in the resin molded product can be maintained at a predetermined amount or more even if vacuum degassing is performed. Further, after disposing the thermosetting resin in the mold 2, the gas concentration of the cross-linking agent in the gas degassed from the inside of the cavity 3 in the process of closing and closing the mold 2 is measured, and the gas concentration of the cross-linking agent is measured. Even in the case where the vacuum degassing is stopped and the molding is performed when the measured value becomes equal to or more than a predetermined value, the amount of the cross-linking agent in the resin molded product can be maintained at or above the predetermined amount.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on a first embodiment shown in the accompanying drawings. 1 and 2 show one embodiment of the present invention. In the figure, reference numeral 2 denotes a mold, and a lower mold 2a and an upper mold 2
b, and the thermosetting molding material 1
Is arranged. As the thermosetting molding material 1, a thermosetting resin such as an unsaturated polyester resin or a vinyl ester resin is used as a base resin, and a styrene monomer as a cross-linking agent mixed in a predetermined amount by weight with respect to the base resin is used. SMC (sheet mold compound) or BMC (bulk mold compound) that performs radical cross-linking polymerization is used. FIG. 1 shows a state during mold closing. That is, after disposing the thermosetting molding material 1 in the mold 2, the inside of the cavity 3 of the mold 2 is evacuated by the vacuum pump 4 to reduce the pressure in order to prevent void formation due to entrainment of air. In the drawing, reference numeral 5 denotes a vacuum packing, and reference numeral 6 denotes a vacuum deaeration hole provided in the mold 2. FIG. 2 shows a state in which the mold closing is completed, in which the vacuum degassing by the vacuum pump 4 is stopped. Here, when the vacuum packing 5 starts fitting while operating the vacuum pump 4 in the mold closing process, a state in which vacuum degassing is possible,
The styrene monomer as a cross-linking agent volatilizes. For this reason,
Although the amount of the cross-linking agent required for cross-linking the base resin is insufficient, in the present embodiment, the amount of the cross-linking agent in the thermosetting molding material 1 to be used is volatilized in advance during the evacuation. It is characterized in that an amount increased by the same amount as the volatilization amount of the crosslinking agent is used.

Next, a specific example of the first embodiment and a comparative example will be described. (Specific Example 1) An unsaturated polyester resin was used as a base resin, and 90% by weight of the base resin and styrene monomer
0% by weight, and 25% by weight of an unsaturated polyester resin thus mixed with a crosslinking agent, 65% by weight of a filler,
B, which is a thermosetting molding material 1 containing 7% by weight of a reinforcing material
10 kg of MC is placed in a mold 2 at 130 ° C. which has been divided in advance (in this case, 250 g of a styrene monomer as a crosslinking agent is contained in 10 kg of BMC). next,
If the pressure in the cavity 3 is reduced to 60 mmHg in order to prevent void formation due to entrainment of air, and 55 seconds are required for closing the mold in the process of closing the mold, 50 g of styrene monomer corresponding to about 20% by weight is volatilized. Was found by measurement. Therefore, in the specific example 1 of the present invention, the amount of the styrene monomer to be volatilized is increased in advance in the thermosetting molding material 1 (that is, 300 g of a styrene monomer as a crosslinking agent in 10 kg of BMC in advance, A mixture corresponding to a base resin weight ratio of 12% by weight is used), which is placed in the mold 2 and the above mold is closed and vacuum degassed. A resin molded product was molded. The resin molded product of Example 1 of the present invention thus formed did not show a whitening phenomenon for 300 hours or more in an immersion test in a hot water environment at 98 ° C.

(Comparative Example) An unsaturated polyester resin was used as a base resin, 90% by weight of the base resin was mixed with 10% by weight of a styrene monomer, and 25% by weight of the unsaturated polyester resin thus mixed with a crosslinking agent was used. , Filler 65
Thermosetting molding material 1 containing 7% by weight of reinforcing material
Is placed in a mold 2 at 130 ° C. which has been previously divided into 130 kg of BMC (in this case, 250 g of a styrene monomer as a crosslinking agent is contained in 10 kg of BMC). Next, the inside of the cavity 3 is decompressed to 60 mmHg in order to prevent void formation due to the entrainment of air.
50 g of styrene monomer corresponding to% by weight were volatilized. Then, after closing the mold, the resin molded article was molded by heating and pressurizing, and the resin molded article of the comparative example thus molded was whitened in 150 hours in a immersion test in a hot water environment of 98 ° C. .

As is clear from the test results of the specific example 1 of the present example and the comparative example 1, it is understood that the specific example 1 of the present example is superior to the comparative example. Next, FIGS. 3 and 4
A second embodiment of the present invention shown in FIG. FIG. 3 shows a state during mold closing. That is, a thermosetting molding material 1 (unsaturated polyester resin, vinyl ester resin, or the like was used as a base resin, and a crosslinking agent composed of a styrene monomer in a weight ratio of 5 to 10% by weight of the base resin was mixed in the mold 2. After the SMC and BMC are arranged, the inside of the cavity 3 of the mold 2 is being evacuated by the vacuum pump 4 to reduce the pressure in order to prevent void formation due to the entrainment of air. Denotes a vacuum packing, and 6 denotes a vacuum deaeration hole provided in the mold 2. FIG. 4 shows a state in which mold closing is completed, in which vacuum degassing by the vacuum pump 4 is stopped. This embodiment is characterized in that after the thermosetting resin is placed in the mold 2, the cavity 3 is filled with the gas of the cross-linking agent in the process of closing and closing the mold 2 to perform molding. Therefore, the mold 2 (the lower mold 2 in the embodiment)
A styrene reservoir 10 is provided outside of (a), and the styrene reservoir 10 and a styrene supply port 12 provided in the lower mold 2a are connected by a pipe 11. Here, styrene pool 1
0 is formed in the high-temperature bath 13. When the vacuum degassing is continued until the mold closing is completed, the styrene monomer is maintained at a temperature higher than the boiling point of the styrene monomer by the high-temperature tank 13, and when the valve 14 of the pipe 11 is kept open, the gasified styrene monomer is filled in the cavity 3. In addition, it is possible to prevent the amount of the crosslinking agent in the thermosetting molding material 1 from decreasing.

Next, a specific example of the second embodiment will be described. (Specific Example 2) BMC that undergoes radical cross-linking polymerization with a styrene monomer as a cross-linking agent mixed at a weight ratio of 10% by weight using an unsaturated polyester resin as a base resin is placed in a previously divided mold at 130 ° C. When the pressure inside the cavity 3 is reduced to 60 mmHg in order to prevent the generation of voids due to the entrainment of air, and 55 seconds are required for closing the mold during the mold closing process, the styrene monomer becomes about 20% by weight.
The degree is volatilized. Therefore, in this embodiment, in order to make up for the amount of styrene monomer volatilized in advance, a styrene pool 10 is provided outside the mold, and the styrene pool 10 is heated to 70 ° C. or higher, which is the boiling point of the styrene monomer under a pressure of 60 mmHg. , And the valve 14 is kept open during the mold closing step, so that the gasified styrene monomer is filled in the cavity 3. After closing the mold, the resin molded article is molded by applying heat and pressure. The resin molded article of the specific example 2 of the present embodiment molded in this manner is subjected to a dipping test in a hot water environment at 98 ° C. for 300 hours or more. No whitening phenomenon occurred.

As is clear from the test results of the specific example 2 and the comparative example, it is understood that the specific example 2 of this embodiment is superior to the comparative example. Next, a third embodiment of the present invention shown in FIGS. 5 and 6 will be described. FIG. 5 shows a state in which the mold is being closed. That is, the thermosetting molding material 1 (unsaturated polyester resin or vinyl ester resin or the like is used as a base resin) in the mold 2 and the weight ratio of the base resin is 5 to 10
S mixed with a crosslinking agent consisting of
(MC or BMC), the cavity 3 of the mold 2 is being evacuated by the vacuum pump 4 to reduce the pressure in order to prevent void formation due to entrainment of air. Denotes a vacuum packing, and 6 denotes a vacuum deaeration hole provided in the mold 2. FIG. 6 shows a state in which the vacuum degassing by the vacuum pump 4 is stopped. In this embodiment, after the thermosetting resin is disposed in the mold 2, the gas concentration of the cross-linking agent in the gas degassed from the cavity 3 in the process of closing and closing the mold 2 is measured. However, it is characterized in that the vacuum degassing is stopped when the measured value of the gas concentration of the crosslinking agent becomes equal to or more than a predetermined value. For this reason, in this embodiment, a mass spectrometer 31 and a valve 32 are provided in the middle of the pipe 30 of the vacuum pump 4. Here, the nitrogen concentration (or oxygen concentration) is measured by the mass spectrometer 31, and when the nitrogen concentration (or oxygen concentration) becomes zero, it is considered that the air in the cavity 3 has been completely replaced by the styrene monomer. Vacuum deaeration is terminated. In this embodiment, by measuring the nitrogen concentration (or oxygen concentration),
In this embodiment, the styrene monomer concentration is measured indirectly, but in another embodiment, the volatilized styrene monomer concentration is directly measured by the mass spectrometer 31, and when the measured value exceeds a predetermined value, a vacuum pump is used. 4 is stopped.

Hereinafter, an example of measuring the nitrogen concentration (or oxygen concentration) will be described as a specific example 3, and an example of directly measuring the styrene monomer concentration will be described as a specific example 4. (Specific Example 3) BMC that undergoes radical cross-linking polymerization with a styrene monomer as a cross-linking agent mixed at a weight ratio of 10% by weight using an unsaturated polyester resin as a base resin is 10k.
g After being placed in a 130 ° C. mold that has been divided in advance, the inside of the cavity 3 is decompressed to 60 mmHg in order to prevent the generation of voids due to entrainment of air, and it takes 55 seconds to close the mold in the mold closing process. 50 g of styrene monomer corresponding to about 20% by weight are stripped off. Therefore, in this embodiment, a mass spectrometer 31 is provided in the middle of the pipe 30 of the vacuum pump 4, and when the nitrogen concentration (or oxygen concentration) is measured by the mass spectrometer 31, it becomes zero one minute later. At this time, it was assumed that the inside of the cavity 3 was completely replaced with the styrene monomer, the operation of the vacuum pump 4 was stopped, and the vacuum deaeration was terminated. After completion of the mold closing, a resin molded product was molded by applying heat and pressure. The resin molded product of Example 3 which was an example of the present invention thus formed did not show whitening for 300 hours or more in the immersion test in a 98 ° C. hot water environment.

As is clear from the test results of the specific example 3 and the comparative example, it is understood that the specific example 3 of the present embodiment is superior to the comparative example. (Specific Example 4) BMC that undergoes radical cross-linking polymerization with a styrene monomer as a cross-linking agent mixed at a weight ratio of 10% by weight using an unsaturated polyester resin as a base resin is 10k.
g After being placed in a 130 ° C. mold that has been divided in advance, the inside of the cavity 3 is decompressed to 60 mmHg in order to prevent the generation of voids due to entrainment of air, and it takes 55 seconds to close the mold in the mold closing process. 50 g of styrene monomer corresponding to about 20% by weight are stripped off. Therefore, in this embodiment, a mass spectrometer 31 is provided in the middle of the pipe 30 of the vacuum pump 4, and the concentration of the styrene monomer volatilized by the mass spectrometer 31 is measured. When it became (25 g for 10 kg of BMC), the operation of the vacuum pump 4 was stopped, and the vacuum deaeration was stopped. After completion of the mold closing, a resin molded product was molded by applying heat and pressure. The resin molded product of Example 4 molded in this manner did not exhibit whitening for 300 hours or more in a immersion test in a hot water environment at 98 ° C.

As is clear from the test results of the specific example 4 and the comparative example, it is found that the specific example 4 of the present embodiment is superior to the comparative example.

[0017]

According to the invention of claim 1 of the present invention, in the method of molding a resin molded product, a thermosetting resin mixed with a crosslinking agent is heated and pressed by a mold to obtain a resin molded product. after arranging a thermosetting resin in the mold, since the mold in advance compensate the same amount as the volatilization amount of the crosslinking agent volatilized by vacuum degassing in the cavity done in Shimekiri course of the mold, the resin The amount of the cross-linking agent in the molded article can be maintained at a predetermined amount or more, and as a result, a decrease in the resin cross-linking density can be prevented.

Further, in the invention according to claim 2 of the present invention, in the method for molding a resin molded product, a thermosetting resin mixed with a crosslinking agent is heated and pressed by a mold to obtain a resin molded product. After arranging the thermosetting resin in the mold, and performing vacuum degassing in the cavity in the process of closing and closing the mold.
Meets gas in the vacuum degassing mold closing has continued to the crosslinking agent into the cavity during the process, since the heating and pressing after mold closing performing forming <br/> shape, even if the vacuum degassing, the resin The amount of the cross-linking agent in the molded article can be maintained at a predetermined amount or more, and as a result, a decrease in the resin cross-linking density can be prevented.

Further, in the invention according to claim 3 of the present invention, in the method of molding a resin molded product, a thermosetting resin mixed with a crosslinking agent is heated and pressed by a mold to obtain a resin molded product. After arranging the thermosetting resin in the mold, measure the gas concentration of the cross-linking agent in the gas that is vacuum degassed from the cavity performed in the process of closing and closing the mold, and the measured value of the gas concentration of the cross-linking agent Since the vacuum degassing is stopped and the molding is performed at the time when the value exceeds a predetermined value, the amount of the cross-linking agent in the resin molded product can be maintained at a predetermined value or more, and as a result, a decrease in resin cross-linking density is prevented. Is what you can do.

[Brief description of the drawings]

FIG. 1 is a sectional view of a state in which a mold is being closed according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state where the vacuum pump is stopped.

FIG. 3 is a cross-sectional view illustrating a state in which a mold is being closed according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a state where the vacuum pump is stopped.

FIG. 5 is a cross-sectional view showing a state in which a mold is being closed according to still another embodiment of the present invention.

FIG. 6 is a sectional view showing a state where the vacuum pump is stopped.

[Explanation of symbols]

 2 mold 3 cavity

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Yamauchi 1048 Kadoma Kadoma, Osaka Pref.Matsushita Electric Works, Ltd. Inventor Masami Matsumoto 1048 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. Tomo Shigeru Oka 5-8, Nishiomibashi-cho, Suita-shi, Osaka Inside of Nippon Shokubai Resin Technology Laboratory Co., Ltd. (56) References JP-A-63-268608 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) B29C 43/00-43/58

Claims (3)

(57) [Claims] In a method of molding a resin molded article, wherein a thermosetting resin mixed with a crosslinking agent is heated and pressed by a mold to obtain a resin molded article, after disposing the thermosetting resin in the mold,
A molding method for a resin molded product, wherein the molding is performed by previously supplementing the same amount as the amount of the cross-linking agent volatilized by vacuum degassing in the cavity performed in the process of closing the mold. 2. A method for molding a resin molded product, in which a thermosetting resin mixed with a crosslinking agent is heated and pressed by a mold to obtain a resin molded product, wherein the thermosetting resin is disposed in the mold.
Vacuum deaeration inside the cavity is performed during the mold closing process.
At the same time, the cavity is filled with the gas of the crosslinking agent during the mold closing step in which the vacuum degassing is continued, and after the mold is closed, heating is performed.
A method for molding a resin molded product, comprising molding by pressing. 3. A method for molding a resin molded product by heating and pressurizing a thermosetting resin mixed with a cross-linking agent using a mold to obtain a resin molded product, wherein the thermosetting resin is disposed in the mold.
Measure the gas concentration of the cross-linking agent in the gas that is vacuum degassed from the cavity performed in the mold closing process, and perform vacuum degassing when the measured value of the gas concentration of the cross-linking agent becomes a predetermined value or more. A method for molding a resin molded product, wherein the molding is stopped and the molding is performed.