JPH10156955A - Manufacture of fiber-reinforced plastic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of bubble or cavity in a layer and to prevent fluffing of fiber on a surface by combining resin composition injected from a first nozzle with fiber reinforcing material separately injected in the air, and then combining it with resin composition injected from a second nozzle by delaying a confluent point. SOLUTION: Molding resin composition injected from a first discharge nozzle 2 is combined with fiber reinforcing material injected separately from it in the air to a mixture. After the first combination, molding resin composition injected from a second discharge nozzle 3 is combined by delaying from the first combination. The nozzle 2 is a central nozzle, and the nozzle 3 is branched from the nozzle 2. The reinforcing material is passed between a rubber roller 5 and a rod 6, cut in a predetermined length by a cutter 7 opposed to the roller 5, fed to a discharge chute 8, and injected. Incidentally, the nozzle 2, the chute 8 and the nozzle 3 are aligned vertically in this order on one straight line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for molding and a fiber-reinforced plastic (hereinafter referred to as "resin") using the composition.
(May be referred to as FRP).

[0002]

2. Description of the Related Art Among the methods for producing fiber-reinforced plastic molded products such as septic tanks and bathtubs, the hand lay-up molding method and the open-mold molding method of spray-up molding method enable production of many kinds and small quantities at normal temperature and pressure. It is widely used because of its low equipment cost. Among them, the spray-up molding method is to provide a gel coat layer on the surface of a previously manufactured mold as needed, and apply a resin composition containing short fibers (fiber reinforcing material) such as glass fiber and unsaturated ester on the surface. It is a method of forming a fiber reinforcement layer by spraying, because large and small bubbles are mixed in the formed fiber reinforcement layer,
In curing the fiber reinforcement layer, a defoaming operation for removing bubbles using a defoaming roll is indispensable.

[0003] In such a spray-up molding method, scattering of a fiber reinforcing material and a resin composition for forming a fiber reinforcing layer, and dispersion of a solvent such as a styrene monomer contained in the resin composition occur. Molding work in an unfavorable environment is forced, and furthermore, it is difficult to mechanize the defoaming work and it must be performed manually, and it takes a long time to mold, and the defoaming work requires skill, so that productivity, There was a problem with quality assurance.

As a method for solving these problems, Japanese Patent Application Laid-Open No. 63-293038 discloses a method in which a fiber-reinforced plastic material, which is a kneaded product of a cut fiber and a resin composition, is pressure-fed into a hose by a pressure pump. There has been proposed a method for producing a fiber-reinforced plastic molded article that does not require defoaming work by applying the composition to the surface of a molding die with an application nozzle. However, in this method, since fibers cut to a length of 12.5 mm or more are entangled with each other and formed into a lump, it is difficult to uniformly apply the fiber-reinforced plastic material to the surface of the mold. In addition, since the glass content is small, the strength of the molded product is reduced, and the viscosity of the kneaded material is increased, so that there is a problem that air bubbles are apt to be mixed in when applied to a molding die.

In Japanese Patent Application Laid-Open No. 5-239259, a resin composition containing a thermosetting resin, a spherical hollow filler and / or a star-like filler, and a fiber reinforced material are sprayed using a spray-up machine. There has been proposed a method for producing a fiber-reinforced plastic molded article which does not require a defoaming step by using a roller or the like by applying it on the surface of a molding die. However,
In this method, when the content of the fiber reinforcing material is high, the wetting of the resin composition and the fiber reinforcing material is reduced, and the generation of fluffing of the fibers on the surface and the large bubbles remaining inside the molded product are left. A defoaming step is required. Further, when the amount of the fiber reinforcing material is small, there is a problem that the strength of the molded article is reduced although the fluff of the fibers and the large bubbles inside the molded article are reduced.

[0006]

According to the first and second aspects of the present invention, when the FRP is formed by the open molding method, the above-mentioned problems of the prior art are solved, and even if the conventional defoaming method is used. The formation of bubbles and cavities in the layer is remarkably suppressed, and a high-quality molded product can be obtained.In addition, even if the defoaming step is simplified, the formation of bubbles and cavities in the layer is suppressed, and An object of the present invention is to provide a resin composition for molding capable of obtaining a molded article having no fluff of fibers, excellent in appearance quality and excellent in strength, and a method for producing a fiber-reinforced plastic molded article using the composition.

[0007]

According to the present invention, there is provided a method for producing a fiber-reinforced plastic molded article by a spray-up method, wherein two injection nozzles of a resin composition for molding are used, and the injection nozzle is ejected from a first ejection nozzle. The molding resin composition and the fiber reinforced material separately jetted therefrom are combined in the air to form a mixture, and thereafter, the joining point of the molding resin composition injected from the second discharge nozzle is delayed. When the mixture is mixed and mixed with the above mixture and sprayed on a molding die, a second discharge nozzle is provided on a side opposite to the molding resin composition sprayed from the first discharge nozzle when viewed from the fiber reinforcement being sprayed. The present invention relates to a method for producing a fiber-reinforced plastic molded product, which is adjusted so that a molding resin composition is sprayed from the mold. Also, the present invention provides a molding resin composition, wherein the molding resin composition injected from the second discharge nozzle is injected from the first discharge nozzle at a distance within a range of 100 to 300 mm from the tip of the first discharge nozzle. The present invention relates to a method for producing the above-mentioned fiber-reinforced plastic molded article to be combined with a mixture of a composition and a fiber reinforcement.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the resin composition for molding in the present invention, an unsaturated polyester resin composition, a vinyl ester resin composition and the like are used, and an unsaturated polyester resin composition is particularly preferred. The unsaturated polyester resin composition contains an unsaturated polyester, a polymerizable monomer, a curing agent, and, if necessary, various additives. The unsaturated polyester used in the present invention is prepared by a known method using an acid component containing an unsaturated dibasic acid and / or an acid anhydride thereof and other polybasic acid used as required, and an alcohol component. And obtained by synthesis.

As the unsaturated dibasic acid and its anhydride, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride and the like are used, and two or more of these may be used in combination. The unsaturated dibasic acid or its acid anhydride is preferably used in an amount of 1 to 100 mol% in the acid component. In addition, these impart moderate hardness to the molded product,
Moreover, in order not to be too brittle, 20 to 90%
More preferably, it is used in an amount of 30 to 70 mol%.

[0010] Other polybasic acids used as needed include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, trimellitic anhydride, succinic acid, azelaic acid, adipic acid, tetrahydrophthalic acid Acids, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, anthracene-maleic anhydride adduct, rosin-maleic anhydride adduct, hetic acid, hetic anhydride, tetrachlorophthalate Acids, chlorinated polybasic acids such as tetrachlorophthalic anhydride, and halogenated polybasic acids such as tetrabromophthalic acid and tetrabromophthalic anhydride are used. These may be used in combination of two or more. These are used by adjusting so that the entire acid component becomes 100% by weight.

As the alcohol component, ethylene glycol, diethylene glycol, propylene glycol,
Dipropylene glycol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol,
1,5-pentanediol, 1,6-hexanediol, dihydric alcohols such as triethylene glycol and neopentyl glycol, glycerin, trihydric alcohols such as trimethylolpropane, tetrahydric alcohols such as pentaerythritol, Two or more of these may be used in combination. The reaction between the acid component and the alcohol component is mainly performed by advancing a condensation reaction, and proceeds by desorbing a low molecular substance such as water generated when both components react to the outside of the system. The acid component and the alcohol component are preferably used in an amount of 1 to 1.3 equivalents, more preferably 1.03 to 1.2 equivalents, per equivalent of the acid component.

Examples of the polymerizable monomer include (meth) acrylic esters such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, divinylbenzene, and methyl methacrylate [(meth) acrylic acid is methacrylic acid and acrylic Means acid. The same applies to the following), and vinyl acetate and the like are used, and two or more of these may be used in combination.
The unsaturated polyester and the polymerizable monomer are preferably used in an amount of 30 to 80% by weight and in an amount of 20 to 70% by weight in consideration of the degree of curing and viscosity. It is preferable to use 35 to 65% by weight.

As the above-mentioned curing agent, an organic peroxide such as methyl ethyl ketone peroxide, benzoyl peroxide, cumene hydroperoxide, lauroyl peroxide can be used as a curing catalyst. These organic peroxides are usually added at a ratio of 0.5 to 3.0% by weight based on the unsaturated polyester resin. It is preferable that the curing agent is prepared separately and is mixed immediately before or at the time of using the molding resin composition. The curing agent is preferably used after being dissolved in an organic solvent such as xylene or toluene, or a liquid plasticizer such as dimethyl phthalate or dioctyl phthalate.

The unsaturated polyester resin composition of the present invention may contain, if necessary, a polymerization inhibitor such as hydroquinone, pyrocatechol, 2,6-di-tert-butylparacresol, a curing accelerator, a dye, a plasticizer, UV absorbers, silica powder, asbestos powder, hydrogenated castor oil, known thixotropic agents such as fatty acid amides, calcium carbonate, a filler having a large specific gravity such as titanium, a silica balloon, a filler having a small specific gravity such as a glass balloon, Various additives such as a stabilizer may be blended.

As a curing accelerator, cobalt naphthenate;
Metal soaps such as cobalt octenoate; quaternary ammonium salts such as dimethylbenzylammonium chloride;
Β-diketones such as acetylacetone, amines such as dimethylaniline, N-ethyl-metatoluidine, and triethanolamine can be used. The blending ratio of the curing accelerator is not particularly limited and is appropriately determined depending on the required curability, but is preferably 0.005 to 5 based on the total amount of the unsaturated polyester and the polymerizable monomer. Used by weight.

In the unsaturated polyester resin composition of the present invention, a molding resin composition comprising an unsaturated polyester, a polymerizable monomer and various additives as necessary is prepared. Preferably, a curing agent is prepared and mixed immediately before or during use of the molding resin composition. The curing agent is preferably used after being dissolved in an organic solvent such as xylene or toluene, or a liquid plasticizer such as dimethyl phthalate or dioctyl phthalate.

The method for producing an FRP molded article of the present invention is performed by a spray-up molding method. In this method, a mold release agent is applied to the surface of a previously produced mold, if necessary.
Form a gel coat layer, spray the fiber reinforcing material and the molding resin composition on the surface thereof, and cure after performing defoaming work such as rolling using an aluminum or pig hair defoaming roll. To manufacture FRP molded products.

The fiber reinforcement is not particularly limited, and various known fiber reinforcements and fiber reinforcements surface-treated with a coupling agent can be used. Examples thereof include glass fibers, carbon fibers, and organic synthetic fibers. Whiskers, ceramic fibers, metal fibers, natural plant fibers and the like. In consideration of the strength and moldability of the molded product, the fiber reinforcing material is used in an amount of 40 to 10 with respect to the total amount of the molding resin composition of 60 to 90 wt%.
%, Preferably 15 to 35% by weight. In addition, it is preferable that the total amount of the molding resin composition and the fiber reinforcement is sprayed onto the molding die at a discharge rate of 2 to 15 kg / min.

Using two discharge nozzles for the resin composition for molding, the resin composition for molding ejected from the first ejection nozzle and the fiber reinforced material ejected separately therefrom are combined in the air to form a mixture. It is said. This merge is called a first merge. After the first merging, the molding resin composition injected from the second discharge nozzle is merged later than this. This merge is called a second merge. The first merging is preferably as close as possible to the first discharge nozzle, particularly preferably at a point within about 10 cm from the first discharge nozzle.
The second confluence may be immediately before the mold.

The molding resin composition sprayed from the second discharge nozzle is mixed with a mixture of the molding resin composition and the fiber reinforcing material (hereinafter referred to as a first mixture) sprayed from the first discharge nozzle. 100 to 300 mm from the tip of the discharge nozzle
It is preferable that they are merged at a distance within the range. More preferably, the distance is in the range of 150 to 250 mm. If the distance is too short, scattering of the resin composition discharged from the upper portion increases, the resin content in the molded product decreases, and bubbles increase. If the distance is too long, the leakage of the fiber reinforcing material and the resin composition becomes worse, and air bubbles tend to increase during molding.

In the present invention, the molding resin composition is
The ejection is performed from the individual ejection nozzles, and the ejection nozzles may be ejection nozzles of separate spray guns or ejection nozzles installed in one spray gun. It is preferable that all the discharge nozzles are installed in one spray gun from the viewpoint of easy forming operation. As the spray gun, if classified according to the mixing system of the molding resin composition containing no curing agent and the curing agent, any of an internal mixing system and an external mixing system can be used.

In the case of the external mixing system, the hardening agent injected from the hardening agent nozzle is mixed with the molding resin composition containing no hardening agent injected from the first and second discharge nozzles. You. The curing agent can be merged only once or twice before either the first merging or the second merging. The resin may be mixed and mixed with the molding resin composition containing no curing agent ejected from the first and second discharge nozzles, respectively, but is preferably mixed before the first mixing.
The molding resin composition is preferably heated to 20 to 50 ° C. in order to improve the wetting with the fiber reinforcement. Attention should be paid to the problem that sagging occurs if the heating temperature at this time is too high.

The ratio of the molding resin composition injected from each discharge nozzle is preferably set as follows. Second
The weight of the molding resin composition injected from the discharge nozzle is preferably adjusted to be 25 to 100% with respect to the weight of the molding resin composition injected from the first discharge nozzle. If the ratio of the molding resin composition from each discharge nozzle is out of the above range, the fibers of the mixture sprayed on the molding die tend to be noticeable, and bubbles are easily entrapped. The operations for foaming tend to increase.

In the present invention, the molding resin composition is sprayed from the second discharge nozzle on the side opposite to the molding resin composition sprayed from the first discharge nozzle when viewed from the fiber reinforcing material being sprayed. It is necessary for the mixture to be adjusted so that the fibers of the mixture sprayed onto the mold do not fluff and reduce the entrapment of air bubbles.

As the fiber reinforcing material to be sprayed, glass roving is preferable. The length of the fiber reinforcing material (cut length of the glass roving) is preferably in the range of 5 to 50 mm, particularly from the viewpoint of preventing dripping of the mixture sprayed on the mold and reducing entrapment of air bubbles. It is preferably 40 mm, more preferably 12 to 25 mm.

In the present invention, the distance between the mold and the spray gun is not particularly limited, but if the distance is too long, air bubbles are likely to be mixed, and if the distance is too short, the resin composition and the fiber reinforcing material are scattered. 400 ~ 1200mm
And more preferably 500 to 700 mm.

The present invention will be described with reference to the drawings. FIG.
FIG. 2 is a side view showing an example of a spray gun for carrying out the present invention, and FIG. 2 is a front view of the spray gun shown in FIG. The molding resin composition is transported from a tank (not shown) of the molding resin composition through the pipe 1 and transported to the first nozzle 2 and the second nozzle 3. The first nozzle 2 is a central nozzle (main nozzle), and the first nozzle 2
And the second nozzle 3 is branched. The fiber reinforced material (glass roving) passes between the rubber roller 5 and the rod 6 supported by the support plate 4, is cut into a predetermined length by a cutter (chopper rotor) 7 facing the rubber roller 5, and is discharged by a discharge shooter 8. It is sent to and injected. The cutter 7 is driven by a motor 9. The curing agent is transported from a curing agent tank (not shown) by a pipe 10 and is ejected from a discharge port 11. When the lever 12 is pulled, the motor 9 is turned on and the molding resin composition, the curing agent, and the fiber reinforcing material are injected in synchronization with each other. In this example, the curing agent is the first
To join the molding resin composition injected from the nozzle. The pressure (gauge pressure) on the transport pipe at the time of injection of the molding resin composition is usually about 1 to 6 kgf / cm ² .

As shown in FIG. 2, the first nozzle 2, the discharge shooter 8, and the second nozzle 3 are preferably arranged in a straight line vertically in this order when viewed from the front. As a result, the molding resin composition is mixed with the glass fibers so as to sandwich the resin composition from above and below, and more uniform mixing can be performed. Further, it is preferable that each nozzle has a structure in which the resin composition to be injected spreads left and right when viewed from the front, and does not spread so much up and down.

[0029]

Next, the present invention will be described by way of examples, which should not be construed as limiting the present invention. In addition,
In the examples, “parts” means “parts by weight” and “%” means “% by weight” unless otherwise specified.

Reference Example (Unsaturated polyester resin composition A)
Production of 5 mol of maleic anhydride, 5 mol of phthalic anhydride, 4 mol of diethylene glycol and 7 mol of propylene glycol in a 2 liter four-necked flask equipped with a stirrer, a condenser, a thermometer and an inert gas inlet, were charged with nitrogen. The reaction was carried out at 210 ° C. by a conventional method under gas introduction. To 55 parts of the obtained unsaturated polyester, 45 parts of styrene and 200 ppm of hydroquinone based on this mixture were added to obtain an unsaturated polyester resin composition A.

Examples 1 to 3 Unsaturated polyester resin composition A1 produced in Reference Example
00 parts, thixotropic agent (silica powder, trade name Aerosil # 20)
1.7 parts, 0.4 parts of 6% cobalt naphthenate, 0.01 parts of 5% copper naphthenate and 0.1 part of dimethylaniline were mixed and dissolved to obtain a viscosity of 0.00. 4
A molding resin composition B having Pa · S, a degree of thixotropicity of 4.4, and a gelling time of 10 minutes was obtained. Viscosity, thixotropic degree and gel time are J
It was measured according to IS K6901. When measuring the gelation time, the molding resin composition B was used as a curing agent.
1.0% of a 55% solution of methyl ethyl ketone peroxide in dimethyl phthalate was used.

The obtained molding resin composition B was further mixed with 40 parts of calcium carbonate based on 100 parts of the molding resin composition. This molding resin composition, a fiber reinforced material comprising a 55% methyl ethyl ketone peroxide dimethyl phthalate solution at a ratio of 1% of a curing agent to the molding resin composition B and glass roving (glass roving manufactured by Nitto Boseki Co., Ltd. (Trade name: 2310TEX-A-673, used to be 33% based on the total amount of the molding resin composition and the fiber reinforcing material) and a spray gun as shown in FIGS. 1 and 2 and shown in Table 1. Sprayed on the mold under the conditions, spiral roll made of pig hair (outer diameter 50 mm, length 150
mm), a defoaming step consisting of rolling a predetermined number of times was immediately performed, followed by curing at room temperature, followed by demolding to obtain a fiber-reinforced plastic molded product. The mold at this time was worked upright. Note that the spray distance is a distance from the tip of the discharge nozzle 2 to the molding die. However, the point of the first merge was set to be about 80 mm from the first discharge nozzle 2. Table 1 shows the points of the second merging.

The obtained molded article is visually inspected for the presence or absence of fluffing due to fibers, and the number of air bubbles having a diameter of 1.5 mm or more in the central portion (150 mm × 150 mm) of the mold surface, and the flat part of the molded article is cut out. The porosity was measured according to JIS K7053 and the strength was measured according to JIS K7055, and the results are shown in Table 1.

[0034]

[Table 1]

Comparative Examples 1 and 2 By applying the method shown in Table 2 in the same manner as in the example, the presence or absence of fluffing of fibers of the FRP molded article according to the example
Table 2 shows the measurement results of the number of air bubbles, the void ratio, and the strength on the mold surface.

[0036]

[Table 2]

[0037]

According to the method of the present invention, even if the defoaming step is simplified (for example, the number of rolls for defoaming is reduced), the incorporation of air bubbles can be prevented. In addition, a molded product having excellent strength without fluffing of fibers can be obtained, and quality and productivity can be improved, such as prevention of defects due to poor defoaming and reduction of manufacturing costs.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a spray gun for implementing the present invention.

FIG. 2 is a front view of the spray gun shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe 2 1st nozzle 3 2nd nozzle 4 Support plate 5 Rubber roller 6 Rod 7 Cutter (chopper rotor) 8 Discharge shooter 9 Motor 10 Pipe 11 Discharge port 12 Lever

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masahiro Kimura 4-3-1-1, Higashicho, Hitachi City, Ibaraki Pref. Hitachi Chemical Co., Ltd. Yamazaki Factory

Claims (2)

[Claims] 1. A method for producing a fiber-reinforced plastic molded article by a spray-up method, wherein two molding resin composition discharge nozzles are used, and a molding resin composition injected from a first discharge nozzle and And a fiber reinforcing material that is separately injected is combined in the air to form a mixture, and thereafter, the molding resin composition injected from the second discharge nozzle is joined to the mixture by delaying the junction point and mixed. When spraying the molding resin, the molding resin composition is ejected from the second discharge nozzle on the side opposite to the molding resin composition ejected from the first ejection nozzle when viewed from the fiber reinforcing material being ejected. A method for producing a fiber-reinforced plastic molded product, characterized in that it is adjusted so as to be performed. 2. A molding resin composition sprayed from a second discharge nozzle is supplied from the tip of the first discharge nozzle at a distance of 100 to 30.
The method for producing a fiber-reinforced plastic molded product according to claim 1, wherein the mixture with the mixture of the molding resin composition and the fiber reinforcement injected from the first discharge nozzle at a distance within a range of 0 mm.