JP2002144334A - Sheet-like preparatory molded body, method for manufacturing molded body using that and molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like preparatory molded body which can be suitably used for manufacturing a glass fiber reinforced molded body having a projected part and a projected line part and can suppress decrease of a strength of the part while a method for manufacturing the glass fiber reinforced molded body is provided. SOLUTION: The sheet-like preparatory molded body comprises SMC wherein glass fibers of various lengths are regularly distributed in a sheet. The method for manufacturing the glass fiber reinforced molded body is provided wherein when a plurality of sheet-like preparatory molded bodies are used, pressurized by heating in a mold and hardened to manufacture a molded body, the sheet-like preparatory molded body is set in the mold so that a projected part and/or a projected line part of the molded body become rich in a short glass fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-shaped preform, a method for producing a glass fiber reinforced molded product using the same, and a glass fiber reinforced molded product. More specifically, the present invention is suitably used for producing a glass fiber reinforced molded article having a convex portion or a convex ridge portion, and the convex portion or the convex ridge portion is sufficiently filled with glass fiber, and the strength of the portion is increased. A sheet-like preform capable of suppressing a decrease in the glass fiber reinforced molded article in which a decrease in the strength of the convex portion or the ridge portion was suppressed while securing the overall strength using the sheet-like preform. TECHNICAL FIELD The present invention relates to a method for efficiently producing a glass fiber reinforced molded article having the above characteristics and obtained by the method.

[0002]

2. Description of the Related Art Fiber reinforced plastics (Fiber Rein)
Forced Plastics (FRP) is widely used as a composite material in various fields, for example, a construction field, a transportation field, an electric field, an aerospace field, and the like. Various methods have been developed as a method for producing this FRP, and the SMC (short for Sheet Molding Compound) method is known as one of the methods. This SMC is obtained by impregnating a resin composition obtained by adding a low-shrinkage agent, a filler, various additives and the like into a resin matrix into a reinforcing material such as glass fiber, and having a thickness of 1 to 5 m.
It is a thermosetting molding material processed into a sheet or plate shape of about m, and is generally cured by heating and pressing in a mold, and an FRP molded body can be easily obtained.

[0003] In the SMC, an unsaturated polyester resin, a vinyl ester resin,
Epoxy resin, phenol resin, etc. are used,
Examples of the low shrinkage agent include polystyrene, polyvinyl acetate, polymethyl methacrylate, polyurethane, and styrene-butadiene block polymer. On the other hand, as the filler, calcium carbonate, talc, aluminum hydroxide, clay and the like are used. Among them, SMC using unsaturated polyester resin and glass fiber
Is used in various industrial fields because it has excellent characteristics such as excellent handling, fluidity, and curability, as well as excellent surface properties, mechanical strength, heat resistance, water resistance, and chemical resistance of the molded product. And form a big market. In particular, it is used for many purposes as a material for home building, such as a panel tank, a septic tank, a cooling tower, a unit bath, and a balcony. In the production of such a molded article by SMC,
When using SMC using long fibers (length 15 to 100 mm) as glass fibers, the mechanical strength of the whole molded body is increased, but the fluidity of the glass fibers is inferior.
There is a problem that the filling amount of the glass fiber into the convex portion or the convex portion such as the flange portion, the rib portion, and the boss portion of the molded body is reduced, and the strength of the portion is inevitably reduced. On the other hand, S using short fibers (less than 15 mm in length) as glass fibers
When using MC, the flowability of the glass fiber is good, and although the glass fiber is sufficiently filled in the convex portions and the ridge portions of the molded product, the strength of the entire molded product is inevitably reduced. The problem arises.

[0004] Therefore, for example, in the case of manufacturing a molded article with ribs, conventionally, S-glass using long fiber glass fiber has been used.
MC and SMC using short fiber glass fiber are prepared respectively, and SMC using short fiber glass fiber on the lower side
Are arranged to improve the filling property of the glass fiber into the ribs. However, in this case, since SMCs having different glass fiber lengths must be prepared, it is unavoidable that the cost is high, and it is necessary to identify each of them. . Attempts have also been made to use panel SMCs in which long fiber glass fibers and short fiber glass fibers are randomly distributed to ensure fluidity and exhibit strength. However, also in this SMC, for example, when manufacturing a molded article having a flange, the flowability of the long fiber glass fiber is inferior, so that the filling amount of the glass fiber in the flange portion is also low, and the strength of the portion is reduced. And
In addition, waves (when the resin flows on a plane and then flows at a right angle, the glass fiber undulates, the surface also undulates) and welds (a trace where the two flows meet where they meet) remains. Even if it is not visible, the weld portion has insufficient glass fiber and thus has poor strength.), And the like, so that the reliability of the strength of the flange portion is low.

[0005]

Under such circumstances, the present invention is suitably used for producing a glass fiber reinforced molded article having a convex portion or a convex ridge portion. A sheet-like preform that is sufficiently filled with glass fibers and can suppress a decrease in the strength of that portion. Using this sheet-like preform, the overall strength is secured, and the strength of the protrusions and ridges is secured. It is an object of the present invention to provide a method for efficiently producing a glass fiber reinforced molded article in which the decrease in the temperature is suppressed, and a glass fiber reinforced molded article having the above characteristics obtained by this method.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have obtained an SMC in which glass fibers having different lengths are regularly distributed in a sheet. Was found to be achieved. The present invention
It has been completed based on such knowledge. That is,
The present invention provides (1) a sheet strip preform made of SMC in which glass fibers having different lengths are regularly distributed in a sheet, and (2) a plurality of the sheet preforms, which are used in a mold. When heating and pressurizing and curing to produce a molded body,
A method for producing a glass fiber reinforced molded article, comprising setting the sheet-shaped preform in a mold so that the convex portions and / or convex ridge portions of the molded article are glass fiber rich in short fibers; And (3) a glass fiber reinforced molded article obtained by the above method.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The sheet-like preform of the present invention comprises:
It is made of SMC, and it is necessary that glass fibers having different lengths are regularly distributed in the sheet. In this sheet-like preformed body, as a preferred embodiment of the regular distribution of glass fibers having different lengths, (1) In an SMC having glass fibers composed of long fibers and short fibers, one end or both ends of the sheet And (2) SMC having glass fibers composed of long fibers and short fibers, the short fibers are richly arranged on one side of the sheet, and the long fibers are arranged on the opposite side. A fiber can be used in which the fibers are arranged in a rich manner and the outer peripheral edge of the sheet is arranged to be a short fiber rich. Here, the long fiber is usually 15 to 100 m in length.
m, preferably glass fibers in the range of 20 to 50 mm, while short fibers are usually 3 mm or more and 15 m in length
m, preferably in the range of 6 to 13 mm.

FIGS. 1 (a) to 1 (c) are plan views showing different examples of the sheet-like preform of the present invention, and FIG. 1 (a) shows a short fiber on both sides of a glass fiber portion 1 of a long fiber. Glass fiber part 2
a and 2b are shown, and (b) shows a structure in which a short fiber glass fiber part 2 is arranged on one side of a long fiber glass fiber part 1. On the other hand, in (c), a short fiber glass fiber portion is disposed on one side of the sheet, and a long fiber glass fiber portion 1 is formed on the opposite surface side, and a short fiber glass fiber portion 2c is formed on the outer peripheral end of the sheet. 1 shows a structure arranged in such a manner. The long fiber portion may contain short fibers so that the long fibers become rich, and the short fiber portion may contain long fibers so that the short fibers become rich.

Using the sheet-shaped preform of the present invention having such a glass fiber distribution, for example, a flange portion,
When manufacturing a molded body having a convex portion or a convex ridge portion such as a rib portion or a boss portion, as described later, the convex portion or the convex ridge portion of the molded body is made to be rich in short fiber glass fibers. By setting a plurality of sheet-shaped preforms in a mold, heating and pressurizing, and curing, the convex portions and the convex portions are also filled with glass fiber satisfactorily, and the strength of the portions decreases. Can be obtained. The sheet-shaped preformed body shown in FIG. 1A can be used, for example, for manufacturing a formed body having flanges on both sides (eg, both sides of a C-shaped trough). It can be used for the production of a molded article having a peripheral flange (such as an outer peripheral portion of a panel water tank), and the sheet-like preformed article shown in (b) is used, for example, for producing a molded article having a flange on one side. Can be. If the preform of (b) is alternately laminated, it can be used for producing a molded body having flanges on both sides. further,
The sheet-shaped preform shown in (c) can be used, for example, for producing a molded product with ribs or a molded product with bosses. As the molding material of the sheet-shaped preform of the present invention,
Usually, an unsaturated polyester resin-based molding material is used.
The unsaturated polyester resin-based molding material is not particularly limited, and a material conventionally used for SMC can be used. This unsaturated polyester resin-based molding material is generally composed of an unsaturated polyester resin, a low shrinkage agent, an inorganic filler, a polymerization initiator, a thickener, and a curing accelerator and other additives used as necessary. I have.

The unsaturated polyester resin is obtained by dissolving an unsaturated polyester obtained by subjecting a dicarboxylic acid component containing an unsaturated dicarboxylic acid and a glycol component to an esterification reaction in a liquid vinyl monomer. The unsaturated polyester has a number average molecular weight of 1,000 to 1,000.
It is a polymer of about 3000, and as the unsaturated dicarboxylic acid, maleic anhydride or fumaric acid is usually used. The liquid vinyl monomer functions as a solvent for the unsaturated polyester and also functions as a crosslinking agent. As the liquid vinyl monomer, a styrene monomer is generally used, and other monomers such as methyl methacrylate, vinyl toluene, α-methylstyrene, divinylbenzene, ethylene glycol di (meth) acrylate, trimethylolpropanetri ) Polyfunctional monomers such as acrylates can be used according to the purpose. Examples of the low shrinkage agent include thermoplastic resins such as polystyrene, polyethylene, polyvinyl acetate, polymethyl methacrylate, saturated polyester, styrene-butadiene copolymer, and styrene-methacrylic acid copolymer.

Examples of the inorganic filler include calcium carbonate, silica, talc, aluminum hydroxide, clay, mica, hollow balloon (glass, shirasu, cement), ferrite, zinc white, and the like.
Calcium carbonate is preferred. This inorganic filler can be subjected to a surface treatment in order to improve dispersibility. Examples of the polymerization initiator include organic peroxides such as methyl ethyl ketone peroxide, acetylacetone peroxide, t-butylperoxybenzoate, benzoyl peroxide, dicumyl peroxide and cumene hydroperoxide. If necessary, cobalt naphthenate; cobalt octoate; N, N-dimethylaniline; N, N-diethylaniline; N, N-dimethyl-
A curing accelerator such as p-toluidine; acetylacetone; ethyl acetoacetate can be used.

As the thickener, magnesium oxide is usually used. Other additives, for example, release agents, antioxidants, ultraviolet absorbers, polymerization inhibitors, colorants,
An impregnating agent, an antifoaming agent, a thixotropic agent and the like can be used as desired. Examples of the polymerization inhibitor include hydroquinone; p-benzoquinone; methylhydroquinone; trimethylhydroquinone; t-butylhydroquinone; catechol; t-butylcatechol; . On the other hand, in the present invention, long fibers and short fibers obtained by cutting a roving are used as the glass fibers to be impregnated with the unsaturated polyester resin-based molding material. The long fiber has a length of usually 15 to 100 mm, preferably 2 to 100 mm.
It is in the range of 0 to 50 mm, and the short fiber has a length of
Usually 3 mm or more and less than 15 mm, preferably 6-13 mm
Of the range. The above roving is usually obtained by bundling about 50 to 4000 single fibers of 5 to 25 μm in fiber with a sizing agent such as polyvinyl acetate, polyester, epoxy resin or polyurethane. The method for producing the sheet-shaped preform of the present invention is not particularly limited, and a known method conventionally used for producing an SMC using an unsaturated polyester resin-based molding material can be employed. . For example, a compound paste is prepared by first kneading the unsaturated polyester resin, a low-shrinkage agent, an inorganic filler, a polymerization initiator, a curing accelerator used as required, and other additives. Next, the unsaturated polyester resin-based molding material obtained by mixing the thickening agent magnesium oxide is immediately supplied to the SMC impregnating machine.

[0013] Next, after applying a predetermined amount of the above molding material to each of the two carrier films, the glass fiber roving is chopped with a cutter on the coating layer of the lower film, and the long fibers and short fibers are distributed in a predetermined distribution. Let go down. Next, an upper film having a coating layer thereon is overlaid so that the coating layer is on the inner side, and rolls are pressed on the upper and lower sides of the overlaid film to impregnate the sandwiched glass fiber with the molding material. Thereby, the sheet-shaped preform of the present invention is obtained. The thickness of the sheet-like preformed body of the present invention thus obtained is
Normally, 1
10 mm, preferably 1 mm to 5 mm. The glass fiber content in the sheet-shaped preform is usually 10 to 70% by weight, preferably 20 to 5% by weight.
It is selected in the range of 0% by weight. Next, a method for producing the glass fiber reinforced molded article of the present invention will be described. About 3 to 4 sheets of the sheet-shaped preform obtained as described above are usually used, and a mold is formed so that the protruding portions and the protruding portions of the obtained glass fiber reinforced formed product are rich in short fiber glass fibers. The glass fibers were sufficiently filled in the convex portions and the convex portions by heating and pressing for about 3 to 5 minutes under the conditions of 5 to 10 MPa and 130 to 150 ° C. A glass fiber reinforced molded article is obtained. The above-mentioned protrusions and protrusions are, for example, flanges, ribs, bosses and the like. The present invention also provides a glass fiber reinforced molded product obtained in this manner. In this glass fiber reinforced molded body, the entire strength is secured, and at the same time, the projections and ridges such as the flanges, the ribs, and the bosses are sufficiently filled with the glass fibers, and the reduction in the strength of the parts is suppressed. In addition, the occurrence of waves and welds is small.

[0014]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 (1) Preparation of unsaturated polyester resin-based molding material 70 parts by weight of an unsaturated polyester resin (a solution of unsaturated polyester in a styrene monomer), 30 parts by weight of a low-shrinkage agent (polystyrene solution), and 100 parts by weight of calcium carbonate Parts by weight, a polymerization initiator (t-butylperoxybenzoate) 1 part by weight, a polymerization inhibitor (p-benzoquinone) 0.01
Parts by weight, 4 parts by weight of a release agent (zinc stearate) and 4 parts by weight of a pigment were kneaded to prepare a compound paste.
Next, 0.22 parts by weight of magnesium oxide as a thickener was mixed with this compound paste to prepare 210 parts by weight of an unsaturated polyester resin-based molding material, which was immediately supplied to an SMC impregnating machine. (2) Production of sheet-shaped preformed body After applying the molding material obtained in the above (1) to each of two 40 μm-thick polypropylene carrier films, the glass roving ( A bundle of 400 single fibers of 13 μm in diameter)
While chopping with a cutter for 5 mm and a cutter for 12 mm, as shown in FIG. 1 (a), it was lowered so that short fiber portions having a length of 12 mm were arranged on both sides of a long fiber portion having a length of 25 mm. The ratio of the total amount of glass fibers to the molding material is 30:70 by weight.

Next, an upper film having a coating layer on the glass fiber is overlaid so that the coating layer is on the inside, and rolls are pressed on the upper and lower sides of the laminated film to form a sandwiched glass. The fibers were impregnated with a molding material to produce a sheet-shaped preform having a thickness of 2 mm. (3) Production of Glass Fiber Reinforced Molded Product Using the sheet-shaped preformed product obtained in the above (2), a panel water tank with a flange height of 75 mm and a full circumference flange was produced as follows. In the sheet-shaped preform of the above (2), the tackiness was lost about one day after the preparation, so the two carrier films were peeled off, and three sheet-shaped preforms were alternately laminated, and a flange was formed. The part was set in a mold so that the short fiber glass fiber was filled.
Next, the panel was heated and pressurized for 4 minutes under the conditions of 7 MPa and 140 ° C. to be cured, thereby producing a panel water tank with a flange around the entire circumference. As shown in FIG. 2, the filling of the glass fiber into the flange portion was good, and the generation of ripples and welds was hardly observed.

Example 2 An unsaturated polyester resin-based molding material was prepared in the same manner as in Example 1 (1), and then, as shown in FIG. 1 (c), according to Example 1 (2). A glass fiber portion of a short fiber having a length of 12 mm is disposed on one side of the sheet, and a glass fiber portion of a long fiber having a length of 25 mm is disposed on the opposite side thereof. A sheet-shaped preform having a thickness of 2 mm, which was arranged so as to be a fiber portion, was produced. The ratio of the total amount of glass fibers to the molding material is 20:80 by weight. Next, a unit bath having a main body thickness of 3 mm, a rib height of 20 mm, and a rib width of 4 mm was prepared using the three sheet-shaped preforms according to Example 1 (3). This product had good filling of the glass fiber into the rib portion, and almost no weld was generated.

Comparative Example 1 An unsaturated polyester resin-based molding material was prepared in the same manner as in Example 1 (1), and only a 25 mm roving cutter was used. A 2 mm-thick sheet-shaped preform consisting solely of 25 mm long fibers was produced. The ratio of glass fiber to molding material is 20:80 by weight. Next, using these three sheet-shaped preforms, a panel water tank with flanges on both sides was produced in the same manner as in Example 1 (3). In this case, as shown in FIG. 3, a resin-rich unfilled portion A was observed, the flange was not sufficiently filled with glass, and undulation B and weld were observed.

[0018]

According to the present invention, the sheet-shaped preform is a SMC.
And glass fibers having different lengths are regularly distributed in the sheet, and are suitably used for manufacturing a glass fiber reinforced molded article having a convex portion or a convex ridge portion. The ridges can be sufficiently filled with glass fibers to suppress a decrease in strength at those portions. Further, according to the method of the present invention, it is possible to efficiently produce a glass fiber reinforced molded article in which a decrease in the strength of a convex portion or a ridge portion is suppressed, using the above-mentioned sheet-like preformed product.

[Brief description of the drawings]

FIG. 1 is a plan view of another example of the sheet-shaped preform of the present invention.

FIG. 2 is a schematic diagram showing a state of filling glass fibers in an example.

FIG. 3 is a schematic diagram illustrating a state of filling glass fibers in a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass fiber part of long fiber 2 Glass fiber part of short fiber 2a, 2b, 2c Glass fiber part of short fiber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F072 AA02 AA07 AB09 AB14 AB22 AB34 AD38 AG03 AH02 AH25 AK05 AK14 AL06 AL07 4F204 AA41 AB25 AC03 AD16 AM36 FA01 FA15 FB01 FB21 FN11 FN15 FQ15

Claims (7)

[Claims] 1. A sheet-shaped preform comprising a sheet molding compound (hereinafter abbreviated as SMC) in which glass fibers having different lengths are regularly distributed in a sheet. 2. The sheet-shaped preform according to claim 1, wherein the SMC having glass fibers composed of long fibers and short fibers has short fibers richly arranged at one end or both ends of the sheet. 3. An SMC having glass fibers composed of long fibers and short fibers, wherein the short fibers are richly arranged on one side of the sheet, the long fibers are rich on the opposite side, and the outer peripheral edge of the sheet is short. The sheet-shaped preform according to claim 1, which is arranged so as to be fiber-rich. 4. The sheet-shaped preform according to claim 2, wherein the short fibers have a length of 3 mm or more and less than 15 mm, and the long fibers have a length of 15 to 100 mm. 5. The sheet-shaped preform according to claim 1, wherein the molding material for SMC is an unsaturated polyester resin-based molding material. 6. A plurality of the sheet-shaped preforms according to claim 1, which are heated and pressed in a mold,
In producing a molded body by curing, the sheet-shaped preform is set in a mold such that the convex portions and / or convex ridge portions of the molded body are rich in short fiber glass fibers. Of producing a glass fiber reinforced molded article. 7. A glass fiber reinforced molded product obtained by the method according to claim 6.