JPH09193150A - Production of glass fiber preform - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and inexpensively produce a glass fiber preform used in a closed system molding method of glass fiber reinforced plastic such as a resin transfer molding method, uniform in thickness and made as thin as possible in apparent thickness so as to be reasonably and simply received in a female and male matched mold to be well adapted to the mold. SOLUTION: A glass fiber preform is produced by bonding glass fibers and a binder compsn. to the outer surface of a preform mold, subsequently placing a press screen made of FRP on the binder compsn. bonded glass fibers before curing the resin in the binder compsn. to shape the binder compsn. bonded glass fibers, and curing the resin in the binder compsn. to integrate the glass fibers and the binder compsn.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for producing a glass fiber preform used in a closed system molding method for glass fiber reinforced plastic (FRP).

[0002]

2. Description of the Related Art Conventionally, FRP has been used for construction materials, housing equipment,
It is widely used as a member for boats, ships, automobiles, vehicles, industrial materials, miscellaneous goods, etc. Many molding methods are known for producing these FRP molded products, and the shape, size, An appropriate molding method is selected depending on the function, performance, and production quantity. Among these molding methods, when mass production is performed, molding is performed with a molding material such as a sheet molding compound or a bulk molding compound, which is the most efficient. On the other hand, large products and products with a small number are formed by an open mold method such as a hand lay-up method or a spray-up method. However, according to the hand lay-up method and the spray-up method, there is a problem that the working environment is poor due to generation of volatile substances, the molding time is long, and the production efficiency is poor.

Therefore, conventionally, instead of the above open molding method, a resin transfer molding method (RTM),
Increasingly, closed system molding methods such as Structural Reaction Injection Molding (SRIM), Resin Injection Vacuum Molding (RIVM), and Low Pressure Metal Die Molding (LPMDM) have been adopted.

The advantages of these closed system molding methods are as follows. That is, the equipment cost is low, the productivity is high, and it is possible to cope with the small and medium volume production. It can be used for the manufacture of FRP molded products for housing equipment, car exterior parts, boats, construction material parts, and the like. High degree of freedom in design, no generation of volatile substances, and good working environment. Both sides of the FRP molded product are smooth and the quality is stable. The working time can be greatly reduced as compared with the hand lay-up method or the spray-up method. In addition, a single resin injection machine can sequentially inject resin into a large number of molds, which is ideal for simultaneously molding many kinds of products. In such a closed system molding method, a continuous mat and a preform are used as the glass fiber reinforcement. Particularly, the preform is suitable for deep drawing or a shape having many curved surfaces.

[0005] By the way, the glass fiber preform used for forming the FRP by a closed system such as RTM is provided with a binder insoluble in the fiber. Must be wet out and free of air bubbles,
In addition, the thickness of the glass fiber preform is uniform, the apparent thickness is as thin as possible, and it fits easily and easily in the molds of both sexes. It is necessary. From an economical point of view, it is possible to produce glass fiber preforms for high-mix low-medium volume production with simple equipment and work without requiring large equipment. Establishing was one of the major challenges of the closed system molding method.

[0006]

However, in the conventional method for producing a glass fiber preform, the dispersed glass shavings are sprayed onto the preform mold by a powerful air suction device, and are sprayed with high temperature hot air to give an apparent thickness. It becomes a relatively thin glass fiber preform. According to such a conventional method, equipment that requires hot air at a high temperature is required to spray almost the same amount of an aqueous binder solution as the glass chop onto the glass chop and evaporate unnecessary moisture to cure the resin. However, there is a problem that it is not energy saving, such as adding heat and cooling.

The present applicant has previously developed and used a binder containing an organic solvent-type special unsaturated polyester resin as a main component, and sprayed glass fibers with a spray gun without using an aqueous solution to obtain an ordinary solution. A glass fiber preform method that cures at a temperature and fixes glass fibers without the need for high-temperature hot air was proposed. According to the previously proposed method, the resin cured product in the binder to which the glass fiber is fixed becomes insoluble in the matrix resin, and in the closed system FRP molding method such as RTM, the glass fiber preform formed in the molding die is set to form the matrix. The glass fiber does not flow when the resin is injected, and wrinkles do not occur, and a homogeneous FRP molded product can be obtained. Further, the method proposed in the future has a feature that it is energy-saving and can be performed by a relatively simple facility.

However, according to the previously proposed method, the air suction force from the mold for attracting the glass chop or the glass mat to the preform mold is relatively gentle, and hot air is not blown to the mold. The apparent thickness of the glass fiber preform tends to be large, especially the general R part, small R part, uneven R part, or the joint part of the glass mat becomes thick and difficult to follow the preform mold. However, there is a problem that it may be difficult to adapt to a molding die in closed system molding such as RTM.

The present inventor, as a result of intensive studies in view of the above points, has solved the above-mentioned problems of the prior art by shaping glass fibers with a binder composition by using a holding screen made of FRP. The present invention has been found to be completed and the present invention has been completed.

An object of the present invention is to provide a glass fiber preform used in a closed system molding method for glass fiber reinforced plastics such as a resin transfer molding method (RTM), in which the glass fiber preform has a uniform thickness and an apparent appearance. The glass fiber preform that can be made as thin as possible and fits comfortably and easily in a molding mold that matches males and females, and that can easily and inexpensively manufacture a glass fiber preform that is familiar to the molding mold. To try to serve. Note that, in the method for producing a glass fiber preform, the knowledge of shaping the glass fiber with the binder composition by using the FRP holding screen is not known until now.

[0011]

In order to achieve the above object, a method for producing a glass fiber preform according to the present invention is a method for producing a glass fiber preform used in a closed system molding method for glass fiber reinforced plastic. That is, the glass fiber and the binder composition are attached to the outer surface of the preform mold, and then, before the resin in the binder composition is cured, the FRP holding screen is placed on the binder composition-attached glass fiber, After shaping the glass fiber with the binder composition, the resin in the binder composition is cured and the glass fiber is integrally bonded with the resin to form a glass fiber preform.

In the above description, glass fibers cut from glass rovings into glass chops are used. In this case, for example, a glass roving cut into glass chops using a FRP spray-up machine is supplied to a mold for preform production, and a binder supply device is used to spray the binder composition on the outer surface of the mold. Then, a glass chop having a uniform thickness is attached together with the binder composition. As such glass fiber, a glass chopped strand mat (glass mat) may be used or used in combination. The glass mat is JIS
It is specified in R3411, and its thickness is EM300.
There are grades from EM to EM900, and variations in thickness are small. The preform having a predetermined thickness is obtained by the selection and combination thereof. The width of the glass mat is also wide enough to accommodate the preforms of molded products.

In order to obtain the smoothness of the FRP surface in combination with the glass mat, a surface mat can be set on the surface. When the rigidity and strength of FRP are required, glass roving cloth (# 570, # 86
0), glass cloth (# 200, # 300) or the like may be put in the middle of the preform or on the side which becomes the back surface of the FRP. Furthermore, in order to have high strength and high rigidity, carbon cloth (as an example, manufactured by Toray, trade name; trading card Co
6343) and Kepler cloth (as an example, manufactured by Toray-Dupont, trade name; Kepler-K281) and the like can be used together with the glass fiber.

[0014]

Next, an embodiment of the present invention will be described. In the method of manufacturing a glass fiber preform according to the present invention, the preform manufacturing mold used is FR.
It is made of a metal plate such as P, an iron plate, a stainless steel plate, a casting, a wire mesh, or the like. A simple FRP mold can withstand long-term use. A hole having a diameter of 5 to 6 mm for air suction is made in the surface of the mold, and the opening ratio is changed between a vertical portion and a horizontal portion of the mold depending on the shape.
The preform manufacturing mold is connected to an air suction device (blow), and while the air is sucked from the inside of the mold, the glass chopping is used to sprinkle the cut glass chops. For example, a binder composition comprising an unsaturated polyester resin raw material, a curing agent, a curing accelerator, and an organic solvent is prepared in advance, and the binder composition is sprayed with a spray gun to attach the binder composition to glass fibers. Next, before curing the resin in the binder composition, a pressing screen made of FRP is placed on the glass fiber to which the binder composition is attached. After shaping the glass fiber with the binder composition in this way, the resin in the binder composition is cured and the glass fiber is integrally bonded with the resin to form a glass fiber preform.

When a glass chopped strand mat (glass mat) is used as the glass fiber, the glass mat is supplied to the outside of the mold. When the glass mat does not fit on the surface due to a locally uneven surface or a curved corner surface (R surface), the glass mat may be bonded to the surface. As the glass mat, one cut into a predetermined size with a cutter or scissors is used, and the bonding surface has a uniform thickness. The bonding width is preferably 10 to 30 mm. Then, for example, every time one or two glass mats are stacked on the outer surface of the mold, the binder composition is sprayed to adhere the binder composition to the glass fibers. Then
Before the resin in the binder composition is cured, a FRP holding screen is placed on the binder composition-attached glass fiber. In any of the above cases, a suction device of 1 to 5 horsepower is used for suctioning air, and the suctioned air amount is, for example, 60 to
It is set to 300 m ³ / min. The amount of the binder adhered to the glass fiber is changed depending on the use and shape of the final product. The amount of the binder adhered is a dry weight after curing and is in the range of 2 to 10 parts by weight based on 100 parts by weight of the glass fiber. It is a proper amount.

Next, the mold for producing a preform is separated from the air suction device, and the mold is left at room temperature or placed in a curing oven at 30 to 70 ° C. to remove the unsaturated polyester resin in the binder composition. Let it cure. Here, the curing time of the resin component in the binder composition was 30 minutes at room temperature.
Curing in the oven is completed in 20 to 30 minutes. Thereby, a glass fiber preform to which a hard binder has adhered can be obtained. When the glass fiber preform cools after the resin component in the binder composition is cured, the FRP press screen is removed, and the glass fiber preform is removed from the mold.

Using the glass fiber preform produced by the above method of the present invention, a glass fiber reinforced plastic can be advantageously molded by a closed system molding method such as ordinary RTM. That is, using a male / female FRP mold, the glass fiber preform manufactured by the above method is set in these molds, the mold is clamped, and RT is injected from the injection hole provided in the mold.
The unsaturated polyester resin raw material composition for RTM mixed with the curing agent is injected at a normal pressure of the RTM method (0.5 to 7 kg / cm ² ) using an M injection device, and a molding temperature of 30 to 70 kg is used.
The molding is performed in a temperature range of 60 ° C. here,
The glass fiber content is usually 20 to 30%, and the injected resin composition is prepared by adding the above-mentioned resin for RTM alone and a filler such as calcium carbonate, aluminum hydroxide and antimony oxide to the resin in an amount of 20 to 30%. Those added at a ratio of 50 parts by weight can be used. As molded products, uniform FR with no wrinkles and good smooth surface
A P-shaped product is obtained.

In the above description, it is desirable to use one FRP press screen for one preform type. However, the divided screens may be joined together or used in combination. .
The press screen is mainly made of FRP, but may be used in combination with a metal plate or a plastic plate. The material of the FRP is mainly glass fiber as a reinforcing material, and an unsaturated polyester resin, a vinyl ester resin, an epoxy resin or the like is used as a matrix resin. Improve heat conduction,
A filler which imparts flame retardancy may be added. Although materials other than FRP can be used, FRP is most suitable in consideration of easy production and economical aspects.

First, a molded article of FRP is made, and a hole is made in the molded article to form a screen. The diameter of the hole is generally larger than the hole formed in the preform mold, and the diameter is 6 to 30 m.
m holes. Depending on the shape of the screen, the diameter of the R portion is reduced, and the diameter is increased on a flat surface. The hole is preferably circular, but may be cut out into an appropriate square to form the hole. The porosity is 10 to 50%, which is generally larger than that of the preform type. When a glass mat is used, it may be possible that the flat portion has a hole diameter of 30 mm or more without a joint portion or the like.
The weight of the hold down screen is important to reduce the apparent thickness of the glass fiber preform. Heavy is better for compressing glass fiber, but lighter is easier to handle. Here, the weight of the presser screen is 5 to 13k.
A weight of g / m ² has been found to be suitable. When the weight is within the above range, the apparent thickness of the desired glass fiber preform can be sufficiently obtained.

The size of the FRP pressing screen varies depending on the weight of the glass fiber used for the preform. The size of the press screen used for a glass fiber weight of 1 kg / m ² is flat, vertical, and bent (R).
In which the distance between the outer surface of the preform die is 2.2 to 2.5 mm. In this case, the rising portion and the vertical surface of the press screen are 3 mm.
Can be tolerated. Such a holding screen is placed on a scattered glass chop or a stacked glass mat and compressed, and the resin in the binder composition is cured in the shape as it is at an ordinary temperature. The glass fiber preform is fixed as it is.

Here, the glass fiber preform produced by the method of the present invention preferably has an apparent thickness of 1.5 times or less the thickness of the mold. When an FRP molded product of 30% glass fiber standard is made by using the FRP press screen described in detail above, the apparent thickness of the preform is set to 1.0 to the thickness of the FRP mold.
It can be suppressed within 1.5 times.

The glass fiber preform manufactured by the above method of the present invention can be easily used as a glass fiber preform having an appropriate shape and thickness in the FRP closed system molding method.

[0023]

EXAMPLES Examples of the present invention will be described below.

Example 1 (1) Production of FRP Pressing Screen First, the top surface diameter was 60 cm, the bottom surface diameter was 30 cm, and the height was 3
We devised a mold to match the preform mold of a 0 cm washbasin-like container (capacity of about 150 L), and made a 7 mm thick FRP molded product whose inner diameter was 2 mm and 4 mm larger than the Brifom mold on each surface into a glass mat and heat-resistant unsaturated polyester. A resin (trade name; Rigolac 150HRBQT, manufactured by Showa High Polymer Co., Ltd.) was used and made by a hand lay-up method. Next, an 8 mm diameter hole was formed in the FRP molded product at a porosity of 30%.
, And a press screen made of FRP was manufactured almost entirely. The weight of the press screen was 7 kg / m ² .

(2) Preparation of glass fiber preform Next, a basin-shaped preform mold having a smooth surface with a capacity of about 150 L (pore diameter 5 mm, opening ratio 25%) was used.
A 1-horsepower air suction device was connected to this mold, and while suctioning air from the inside of the mold while sucking and removing air with a suctioned air amount of 60 m ³ / min, an FRP spray-up machine (HIS model 80, ChoperUnit, VenusPro
duct Inc. And cut into glass chops from a glass roving and supplied, and a binder composition is sprayed from a resin supply device to provide a uniform thickness of glass chops 900 g / m ² (type a) and 1800 g / A glass fiber preform according to the present invention having m ² (type b) applied thereto and pressed using a pressing screen and a glass fiber preform of a comparative example not using a pressing screen were prepared. Next, the preform-manufacturing mold is separated from the air suction device, and this mold is subjected to F.
The unsaturated polyester resin in the binder composition was cured by placing it in a curing furnace for RP. At this time, curing in the furnace is 2
It took 5 minutes. As a result, a dried glass fiber preform to which a hard binder was adhered was obtained. The amount of the attached binder was 8% by weight.

(3) Production of FRP molded product From the glass fiber preform produced by the method of the present invention (2), a glass chop of 1800 g / m ^{2 was used.}
A glass fiber reinforced plastic (FRP) molded product was produced by the closed system molding method of RTM using the glass fiber preform according to the present invention, which was adhered and pressed using a pressing screen, as follows. That is, male and female FRP molds of FRP containers made for RTM were used, and the glass fiber preform was set in these molds and clamped. Then
An injection device (Hydrajec) is injected from an injection hole provided in the mold.
ter VenusProduct Inc. 3) using an unsaturated polyester resin raw material composition for RTM (trade name: Rigolac 162R, manufactured by Showa Polymer Co., Ltd.)
The injection was performed at a pressure of kg / cm ² . The molding temperature of the mold was 45 ° C., and the curing time was 50 minutes. The FRP molded product thus obtained had no wrinkles on the surface, had a smooth surface, and was uniform and had a good surface condition. Note that FR
The glass fiber content of the P molded product was 25% by weight.

Example 2 (1) Manufacture of FRP presser screen The FRP presser screen manufactured in exactly the same manner as in Example 1 was used.

(2) Preparation of glass fiber preform Next, a glass fiber preform was manufactured in the following manner by using the same preform manufacturing mold as that used in Example 1. 1 for the mold for preform manufacturing
A horsepower air suction device was connected, and the glass mat was supplied to the outside of the mold while sucking air from the inside of the mold. Here, the glass mat has a thickness of EM450.
(JIS R3411) is used, and four mats are wrapped in a width of 25 mm and connected to each other. One ply is used as a ply, and a mat of three plies is superposed on the outside of the mold. The composition is sprayed, the binder composition is adhered to the glass fiber, and the outer surface of the mold has a uniform thickness of 1800 g / m.
² (type c) was adhered and a glass fiber preform according to the present invention, which was pressed using a pressing screen, and a glass fiber preform of a comparative example, which did not use the pressing screen, were prepared. At this time, the air of a suction air amount of 60 m ³ / min was sucked and removed from the inside of the mold by the air suction device.
Then, the glass fiber preform to which the binder composition was attached was cured in the same manner as in Example 1 above to cure the unsaturated polyester resin in the binder composition attached to the glass fiber, and the glass fiber preform to which the hard binder was attached. I got a reform. The amount of the attached binder was 3% by weight.

(3) Manufacture of FRP molded product With the glass fiber preform manufactured by using the pressing screen by the method of (2) above, the closed system molding method of RTM was performed in exactly the same manner as in Example 1. A glass fiber reinforced plastic (FRP) molded product was manufactured. The obtained FRP molded product has no wrinkles on the surface,
It had a smooth surface and was homogeneous and had a good surface condition.

The characteristics of the glass fiber preforms in the first and second examples are summarized in Table 1. As is clear from the results in Table 1, the FR according to the method of the present invention
The apparent thickness of the glass fiber preform produced by using the P-made holding screen could be suppressed to 1.0 times the thickness of the FRP mold. In this way, the glass fiber preform has a uniform thickness, an apparent thickness is thin, and it is reasonably possible in a molding mold that matches male and female,
It had a thickness that fits easily and was a good match for the mold.

On the other hand, according to the method of the comparative example not using the FRP presser screen, the apparent thickness of the glass fiber preform is 1.5 to 2.5 times when the glass chop is used, and When the glass mat was used, the ratio was 1.25 to 1.5 times, and the glass fiber preform did not fit in the molding die and was difficult to set in the male / female FRP type.

[0032]

As described above, the present invention is a method for producing a glass fiber preform used in a closed system molding method for glass fiber reinforced plastic, wherein the glass fiber and the binder composition are provided on the outer surface of the preform mold. Before the resin in the binder composition is cured, a FRP holding screen is placed on the binder composition-attached glass fiber to shape the glass fiber with the binder composition, and then in the binder composition. Let's cure the resin of
Glass fibers are integrally bonded with resin to form a glass fiber preform, and according to the method of the present invention, a glass fiber preform for use in glass fiber reinforced plastic can be manufactured by a closed system molding method. Moreover, the thickness of the glass fiber preform is uniform, and the apparent thickness can be made as thin as possible,
A glass fiber preform having a thickness that fits comfortably and easily in a male and female mold, and which is well suited to the mold, can be manufactured easily and inexpensively.

Further, by using the glass fiber preform obtained by the method of the present invention, all the FRP molded products are homogeneous, have no wrinkles and have a smooth surface, and the quality of the molded products is high. A product with satisfactory appearance and physical properties can be obtained. In addition, it does not require a large-scale facility as in the past and can be carried out by a simple operation using a simple facility. Also, it does not require high temperature and hot air,
Since energy saving can be achieved, there is an effect that the economic merit is very large.

[0034]

Claims (7)

[Claims] 1. A method for producing a glass fiber preform used in a closed system molding method for glass fiber reinforced plastics, which comprises depositing glass fiber and a binder composition on the outer surface of a preform mold, and then applying the binder composition in the binder composition. Before curing the resin of 1., a FRP pressing screen is placed on the binder composition-attached glass fiber to shape the glass fiber with the binder composition, and then the resin in the binder composition is cured to form the glass fiber. A method for producing a glass fiber preform, which comprises integrally bonding the above with a resin to form a glass fiber preform. 2. A glass chop cut from glass roving is used as the glass fiber.
A method for producing the glass fiber preform described. 3. The method for producing a glass fiber preform according to claim 1, wherein a glass chopped strand mat (glass mat) is used as the glass fiber. 4. The FRP presser screen has a hole diameter of 6 to 30.
The method for producing a glass fiber preform according to claim 1, which has a hole of mm. 5. The opening ratio of the FRP presser screen is 10
The method for producing a glass fiber preform according to claim 1, which is -50%. 6. The weight of the FRP presser screen is 5 to 1
The method for producing a glass fiber preform according to claim 1, wherein the glass fiber preform has a pressure of 3 kg / m ² . 7. The size of the FRP presser screen is such that the distance between the horizontal surface, the vertical surface, and the outer surface of the preform mold at the bent portion (R portion) is 2.2 for a glass fiber weight of 1 kg / m ^2. The method for producing a glass fiber preform according to claim 1, wherein the glass fiber preform has a thickness of about 2.5 mm.