JPH09235457A - Molding resin composition and production of fiber-reinforced plastic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding resin composition which can give fiber-reinforced plastic moldings freed from contamination with bubbles in spite of the decreased times of deaeration, freed from fiber fluffs, and having excellent strength by employing conventional deaerating operation in the open mold method. SOLUTION: This composition comprises an unsaturated polyester, a polymerizable monomer, a hydroxylated polybutadiene or its derivative, and a fatty acid. The weight ratio of the polybutadiene or its derivative to the fatty acid is 0.98/0.02 to 0.75/0.25. The production process comprises molding this composition by the open mold method.

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 although the fiber fluffing and large air bubbles inside the molded article are reduced, the strength of the molded article is reduced.

Further, there is a method of adding silicone to the resin composition. However, in this method, although the bubble removal is slightly faster, it is not sufficient, and a long-time defoaming operation using a roller or the like is performed, but the void ratio (remaining bubble ratio) of the molded product is high. Further, when the defoaming operation is simplified, large bubbles inside the molded article are slightly reduced, but small bubbles remain innumerably, resulting in a problem that the strength of the molded article is reduced.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art when molding an FRP by the open molding method, and even if the conventional defoaming work method is used, bubbles and cavities in the layer are eliminated. It is possible to obtain a molded product of excellent quality by significantly suppressing the occurrence of, and to suppress the generation of bubbles and cavities in the layer even if the defoaming process is simplified, and there is no fiber fuzz on the surface. Provided are a molding resin composition capable of obtaining a molded product excellent in appearance quality and strength, and a method for producing a fiber-reinforced plastic molded product using this composition.

[0008]

The present invention comprises an unsaturated polyester, a polymerizable monomer, a polybutadiene having a hydroxyl group or a derivative thereof and a fatty acid, and (A) a polybutadiene having a hydroxyl group or a derivative thereof. B) fatty acid, (A) :( B) = 0.98: 0.02-0.7
The present invention relates to a resin composition for molding which is compounded in a weight ratio of 5: 0.25 and a method for producing a fiber-reinforced plastic molded product which is molded by the open molding method using the resin composition.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The unsaturated polyester used in the present invention comprises an acid component containing an unsaturated dibasic acid and / or its acid anhydride and optionally other polybasic acid, and an alcohol component. And can be obtained by synthesizing by a known method. As the unsaturated dibasic acid and its acid anhydride, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride and the like are used, and two or more of them may be used in combination. The unsaturated dibasic acid or its acid anhydride is
It is preferable to use 1 to 100 mol% in the acid component.
Further, in order to impart appropriate hardness to the molded component and not to be too brittle, these are 20 to 90 mol% in the acid component.
It is more preferably used, and particularly preferably 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 adjusted and used so that the whole acid component may be 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 the former 30 to 80% by weight and the latter 20 to 70% by weight, in particular the former 45 to 65% by weight and the latter in consideration of the curing degree and the viscosity. It is preferable to use 35 to 5% by weight.

As the polybutadiene having a hydroxyl group in the present invention, 1,4-polybutadiene, 1,2-polybutadiene, and polybutadiene containing a mixture of 1,4-bond and 1,2-bond have a hydroxyl group at or near the terminal. The introduced polybutadiene derivative having a hydroxyl group includes a hydrogenated product of a polybutadiene having a hydroxyl group. For example,

Embedded image (In the formula, n is an integer of 1 or more),

Embedded image (In the formula, n is an integer of 1 or more),

Embedded image (In the formula, n is an integer of 1 or more),

Embedded image (In the formula, n is an integer of 1 or more),

Embedded image (In the formula, n is an integer of 1 or more) and the like.

The polybutadiene having a hydroxyl group or its derivative has a number average molecular weight (value measured by gel permeation chromatography and converted using a calibration curve of standard polystyrene) in the range of 1,000 to 5,000. Preferably. If the number average molecular weight is too large or too small, bubbles tend to be caught and bubbles may escape during spraying.

Examples of the fatty acid used in the present invention include soybean fatty acid, linseed oil fatty acid, castor oil fatty acid, tall oil fatty acid and the like.

In the present invention, (A) a polybutadiene having a hydroxyl group or a derivative thereof and (B) a fatty acid are (A) :( B) = 0.98: 0.02 to 0.75: 0.
25 weight ratio, preferably 0.95: 0.05 to 0.8
Used in a weight ratio of 0: 0.20. (A): (B) = 0.
Outside the range of 98: 0.02 to 0.75: 0.25, bubbles are often entrained during spraying, and if the number of defoaming operations in the defoaming work is reduced, the effect of bubble removal cannot be obtained. The blending amount of the total amount of the components (A) and (B) in the above ratio is 0.01 based on the total amount of the unsaturated polyester and the polymerizable monomer in view of the degree of bubble entrapment and bubble escape during molding. ~ 2.
The range is 0% by weight, preferably 0.05 to 0.8% by weight, and more preferably 0.1 to 0.5% by weight. When the content is less than 0.01% by weight, the effect of defoaming cannot be obtained by reducing the number of defoaming operations in the defoaming work, and when it is more than 2.0% by weight, the curability is poor. It becomes worse, thixotropic property is lowered, and sagging easily occurs during molding.

For curing the molding resin composition according to the present invention, an organic peroxide such as methyl ethyl ketone peroxide, benzoyl peroxide, cumene hydroperoxide or lauroyl peroxide can be used as a curing catalyst. These organic peroxides are usually added in a proportion of 0.5 to 3.0% by weight based on the total amount of unsaturated polyester and polysynthetic monomer. Further, as a curing accelerator, metal soaps such as cobalt naphthenate and cobalt octenoate, quaternary ammonium salts such as dimethylbenzylammonium chloride, β-diketones such as acetylacetone, dimethylaniline, N-ethyl-
Amines such as metatoluidine and triethanolamine can be used. The mixing ratio of the curing accelerator is not particularly limited and may be appropriately determined depending on the required curability, but is preferably 0.1 to 5 relative to the total amount of the unsaturated polyester and the polymerizable monomer. Used by weight percent.

The molding resin composition of the present invention may contain hydroquinone, pyrocatechol, 2,6-
Polymerization inhibitors such as di-tert-butyl para-cresol, curing accelerators, dyes, plasticizers, UV absorbers, silica powder, asbestos powder, hydrogenated castor oil, known thixotropic agents such as fatty acid amides, fillers, You may mix | blend various additives, such as a stabilizer. 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.

FRP using the molding resin composition of the present invention
The method for producing a molded product is as follows. A mold releasing agent and a gel coat layer are applied to the surface of a prefabricated mold if necessary, and a molding resin composition in which a fiber reinforcement and the above-mentioned various additives are blended on the surface is used. Pile or spray at the same time a molding resin composition containing a fiber reinforcement and the above various additives, cured after performing defoaming work using a defoaming roll made of aluminum or pig hair, It consists of manufacturing FRP molded parts. These methods are open mold construction methods such as the well-known hand lay-up molding method and spray-up molding method.

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 fiber, carbon fiber, and organic synthetic fiber. Whiskers, ceramic fibers, metal fibers, natural plant fibers and the like. Considering the strength and moldability of the molded product, the fiber reinforcing material is preferably 15 to 40% by weight based on the total amount of this and the resin composition for molding. In the spray-up molding method, the fiber reinforcing material is added in an amount of 20 to 3 with respect to the total amount of the fiber reinforcing material and the molding resin composition.
It is particularly preferable to be 5% by weight.

[0021]

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
Preparation of 5 mol of maleic anhydride, 5 mol of phthalic anhydride, 4 mol of diethylene glycol and 7 mol of propylene glycol were charged into a 2-liter four-necked flask equipped with a stirrer, a condenser, a thermometer and an inert gas inlet, and nitrogen was introduced. The reaction was carried out at 210 ° C. by a conventional method while introducing gas. 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 The unsaturated polyester resin composition A produced in Reference Examples, thixotropic agent (silica powder, trade name Aerosil # 200, manufactured by Nippon Aerosil Co., Ltd.), polybutadiene glycol derivative (Nippon Soda Co., Ltd.) ), Trade name PBG-2000, the above [Chemical formula 2]
, The number average molecular weight of 2,000, soybean oil fatty acid (manufactured by NOF CORPORATION), cobalt naphthenate and dimethylaniline are mixed in the composition shown in Table 1 and dissolved.
A molding resin composition having the viscosity, thixotropic degree and gelation time shown in Table 1 was obtained. JIS, viscosity, thixotropy and gelation time
It was measured according to K6901. When measuring the gelation time, 1.0% of a 55% methyl ethyl ketone peroxide in dimethyl phthalate solution was used as a curing agent for the molding resin composition.

Using the molding resin composition and 100 parts by weight of the molding resin composition obtained, 1 part by weight of a 55% methyl ethyl ketone peroxide in dimethyl phthalate solution was used to obtain 500 mm (width) × 700 mm (length) Sa) x 1
A glass plate of 0 mm (thickness) is used as a mold, and a fiber reinforced material (glass roving manufactured by Nitto Boseki Co., Ltd., product name 2310TEX-A
-673) was applied with a spray-up machine (trade name: HL5000) manufactured by Togiken Co., Ltd. so that the content of 33% was 33%, and a spiral roll made of pig hair (outer diameter 50 mm, length 150)
mm), a defoaming step consisting of rolling a predetermined number of times shown in Table 1 was immediately performed to cure at room temperature and then demolded to obtain a fiber-reinforced plastic molded product. The mold at this time was worked upright. Presence or absence of fluff due to the fibers of the obtained molded product and the central part of the mold surface (150 mm × 150 mm)
The number of bubbles with a diameter of 1.5 mm or more in the above was visually observed, and the flat surface of the molded product was cut out to JIS K70.
The void ratio was measured according to 53 and the strength was measured according to JIS K7055, and the results are shown in Table 1.

[0025]

[Table 1]

Comparative Examples 1 and 2 By the same method as described in Examples, molding resin compositions and fiber reinforced plastic moldings having the formulations shown in Table 2 were produced, their properties were measured, and the results are shown. It shows in Table 2.

[0027]

[Table 2]

[0028]

By using the molding resin composition of the present invention,
Even if the defoaming process is simplified by using the conventional defoaming work method in the open mold method (for example, the number of rolls for defoaming is reduced), it is possible to prevent bubbles from being mixed in and to cause fiber fluffing. It is possible to obtain a molded product having no strength and excellent strength, and it is possible to improve quality and productivity such as prevention of defects due to defective defoaming and reduction of manufacturing cost.

Claims (3)

[Claims] 1. An unsaturated polyester, a polymerizable monomer, a polybutadiene having a hydroxyl group or a derivative thereof and a fatty acid, and (A) a polybutadiene having a hydroxyl group or a derivative thereof and (B) a fatty acid, : (B) =
A molding resin composition, which is compounded in a weight ratio of 0.98: 0.02 to 0.75: 0.25. 2. A total amount of (A) hydroxyl group-containing polybutadiene or its derivative and (B) fatty acid is 0.01 to 2.0% by weight based on the total amount of unsaturated polyester and polymerizable monomer. The resin composition for molding according to claim 1, wherein 3. A method for producing a fiber-reinforced plastic molded product, which comprises molding the resin composition for molding according to claim 1 or 2 by an open molding method.