JPS58162324A - Manufacture of fiber reinforced plastic molded product - Google Patents

Abstract

PURPOSE:To obtain a molded product of high grade by a method wherein a gel coat layer and a mixture layer of hardened resin and reinforced fibers on said layer are formed on one of a pair of molds, then a core material and further a material of reinforced fiber layer are set and hardening resin is injected into the molds. CONSTITUTION:To take an example, a bottom force 21a for a left side panel 2 is sprayed with unsaturated polyester resin to form a gel coat layer 22, the upper part thereon is coated by the hand lay up method with glass fiber contained unsaturated polyester resin, and a core material 24 of machined hard polyurethane foam is put on it to be heated and precured. Then, the prefoam 25 sprayed with glass fibers and unsaturated polyester resin is set in the prefoam molds both forces 21a, 21b are closed, and unsaturated polyester resin is forced in from an injection hole and aftercured to obtain the molded product. This method causes no shrink, no offset, no crack and can elevate appearance.

Description

[Detailed description of the invention] This paper relates to a new koji method for molded products (called FILP).

More specifically, FR with a gel coat layer and a core material
The F molded product is processed using the resin injection method (hereinafter referred to as single KR).
/I method).

FRP is a strong structural material molded from wood, usually a combination of curable resin, catalyst, additives, and reinforcing fibers, and is relatively lightweight and can be molded into a wide variety of molded products. Therefore, it is used in a wide variety of applications, from automobiles and ships to bathtubs, septic tanks, and even flat plates and corrugated plates, and among them, it is used in relatively simple shapes.

FR? The main molding methods are the hand lay-up method, the spray-up method, and the contact pressure molding method represented by the VI method. This is a problem in manufacturing, but not only is the work efficiency slow and the molding cycle is long, but the flat surface of the molded product is not smooth due to the large shrinkage that occurs when the curable resin hardens, and the surface of the molded product has to be reinforced. The fibers stand out and cause a poor appearance.

On the other hand, the Matsushidodai method, the 11M0 method, and the BMO method.

Press molding methods such as the above are more efficient and produce fresh noodles compared to contact pressure molding methods such as the hand lay-up method and the spray-up method.

Compared to the contact pressure molding method, the equipment costs are higher, and there is a limit to the size of the product that can be molded, and the disadvantage is that reinforcing fibers come out on the surface of the molded product due to shrinkage during curing of the curable resin. It will be done.

Among the FRP molding and casting methods such as Jin, the R/I method is characterized by higher durability than other contact pressure molding methods, and the appearance of both sides of the molded product is relatively good. It can be said that this molding method is far more suitable for medium-sized mass production.

The Vx method generally uses a pair of male and female molds made of FRP, etc. A reinforcing fiber preform such as glass fiber is placed in the mold in advance, the mold is closed, and unsaturated polyester is then injected through injection holes placed at appropriate positions. After press-fitting a hardening resin such as resin, plug the injection hole and heat it at a low temperature (for example, room temperature to
This is a method of curing and molding at a temperature of approximately 50°C. The basic molding process includes (1) IJ! cleaning and mold release treatment (in some cases gel coat layer formation is also performed), (filling of 21 preforms (including filling of core material), (3) ) Mold closing, (4) Clamping, (5) Curing resin injection, (6) Curing, ()) Mold opening, (8) Mold removal, and (9) Post-processing (Paris processing, after-cure, etc.) Become.

However, the R/I method is currently only applied to molded products with a relatively simple shape, and is only applied to molded products with a complex shape and relatively large size that require high rigidity. That never happened.

However, the present inventor has proposed that each vehicle body member of a vehicle, which has a complicated shape and is relatively large, for example, has a cargo platform at the rear of the vehicle body and a rear pod that heats the cargo platform, has a νR.
We considered making them made of P, and tried molding them using the iL/I method described above.

That is, FIG. 1 is a perspective view of the body of the automobile, and (1) shows the main body made of steel, for example, the left side panel (Mai, right side panel (3), rear roof I4), back door (2), front roof (6)
, we attempted to make each component such as the sunroof (7) FIP.

# (8) :! f and (1B) are window openings.

Hereinafter, the conversion of the left side panel (2) to F-BP will be explained as an example. The second one is an FRP reflex panel (
2) is a perspective view seen from the back side, Fig. s3 is a perspective view seen from the back side, Fig. 4 is a perspective view of Figs. This is an enlarged view of the circle (turn) part. In the drawing, Yiteng is FRP Peng, I is the preform of reinforcing fiber such as glass fiber, and II is the left side panel (the part shown on the front side of the circle). This is a gel coat layer provided on the outside of the rRPJII fist.The shaft is a core material placed in areas where strength and rigidity are required.

However, F with the above-mentioned gel coat layer and core material
It has been found that when RF molded products are manufactured by the l/I method, the following problem occurs.

That is, at the part where the core material H is inserted, the structure is sandwiched between the core materials a4tJ1PRPjIIla* as shown in FIG. 5, and the upper and lower y n plf of the core material I
l (l1m) and (llb) together form one FRP
It becomes layer (116), but 1np of the part where core material I exists
layer (11m) and the FRP layer in the area where core material a4 does not exist (
Even if an attempt is made to obtain a molded product in which the yap@ and the yap form the same plane, a step (8) will occur on the surface of the yap@ after curing.

The reason for this is that in the case of molding using the R/I method, gel coat JIi1- is formed on the lower mold, and then reinforcing fiber preform (12 m), core material No. 6, and reinforcing fiber preform (12 k) are set in order. After that, the lower and upper molds are closed, hardening resin is injected, and the mold is formed. R.P.
In the layer (l1m), the preform is 1 fat, while the FR
Since the preform is 2jll* in the P layer (lie), y RP II (lie) is the 1BP layer (l1m)
The thicker (FRP layer (l1m) and FRP layer (l1m)
The curing shrinkage of 7111(lle) occurs around the center planes (15m) and (15*) of those layers, respectively, but the FBF-(11·) is thicker than the FILP layer (11m), and their Center plane of curing shrinkage (15 m) and center plane (15 m)
・) is out of alignment. The size of the gap (8) is based on the center plane (15@), and is calculated using the formula: Rate, (attack),!
1., and! @ represents 717 layers (1
1m) thick rhinoceros (am) # and FILP pigeon (lie)! all).

In order to reduce this step (8), 717 layers (l1m
) and the thickness T(1) of F RP @ (11*) should be as small as possible, preferably I! @
You only need to set wg〒C, but if you do that, as shown in Figure 7, < F I P II (l1m) and (til
Sink marks are likely to occur on the surface of the molded product in the area where the +) is combined to form the FBF pigeon (11).

This is because in the part where the two layers y it p @ meet, a resin-rich part is inevitably created where the reinforcing fibers (12m) and (12b) are not present, but in that 5 part, there are no reinforcing fibers. Because there is no such thing, only 2 to 3% of the reinforced and fiber-strengthened parts are cured, whereas 5 to 10
% also shrinks. A molded product with surface sink marks AE cannot be used as a vehicle body panel or the like where appearance is important.

When a part rich in woven resin occurs, there is a large difference in curing shrinkage rate from the part reinforced with reinforcing fibers as described above, so internal cracks occur and the strength of that part decreases.

In order to prevent the above-mentioned step (8) or sink mark from occurring, the inventors have found that in order to prevent the occurrence of the above-mentioned step (8) or sink mark, as shown in FIG. #Yo(ll
We discovered that it is sufficient to use core material 0 having a fin (14 m) in the part where b) is combined to form the F RP layer (IIg), and recently filed an application (Patent No. 11i111856-15).
No. 97.61 M). However, the fin part (14m)
When using core material A4 with
F RP @ (lie,) f) side WiJ ni protruding L tee, so FIL Ta) with a thickness of 717 layers (l1m)
There is no risk of sink marks even if you get close to the rhinoceros of Fjll (lie). Therefore, the FBI' layer (11 m
) can be made as close as possible to the thickness of F RP @ (lie), and the step difference can be made as small as possible. However, it is difficult to manufacture the core material with fins by post-processing, and it is necessary to manufacture it by making a special mold and molding it into a predetermined shape, which increases the manufacturing cost of the core material. There is a problem that In addition, when using a core material with fins, in order to reduce the level difference to a level that cannot be seen with the naked eye, the thickness of the 717 layer (Ta) and the thickness of the FILF layer (lle) must be 717 (l1 m). 1
) Ta/'f's > 2/3, but it is difficult to position the core material so as to satisfy this condition.

The next threshold is when there is a part with a complicated shape, such as a part of a corner, on the surface of the molded product, as shown in Figure 9 (corresponding to the enlarged view of the circle (B) in No. 4). Cracks are likely to occur in the gel coat layer in that area, impairing the appearance quality. Reinforcing fiber priome (12m
) is made by binding together short glass fibers, etc. with a length of about 5, Q mm, with a binder, so it is difficult to change the shape to match one corner part with a small radius of curvature, and it is difficult to change the shape to fit one corner part with a small radius of curvature. As mentioned above, the 6th place to set the reform is not very precise, so it will not be in the correct position or it will be misaligned, and a resin-rich part will occur in some corners. Since the 11up cured condensation M-tei is larger than the part where the reinforcing fibers are present, an internal crack will occur in this part aη, and with the occurrence of this internal crack, a crack will occur in the gel coat layer (2) in that part. be.

Furthermore, on top of the gel coat PM (total), reinforcing fiber preform (12 m), core material A4g, and reinforcing fiber preform I
J 7 ohms (12b) are set in this order, curable resin is injected, and cured. In the VI method Li1, it is generally difficult to position the core material a◆, and it tends to shift vertically and horizontally from a predetermined position. If the core material U deviates from the specified position, resin-rich areas are likely to occur, causing internal cracks.
In addition, if the core material 14 is made of polyurethane foam, gases such as carbon dioxide will come out from the cells due to heating and concentrate at the boundary with the INLF@ core material. Due to the deviation of O◆, ff1LP plow (l1m)
When the size of the rhinoceros becomes smaller, the FRP layer (l1m) cannot withstand the gas pressure and separates from the core material I.
It is celebrated as a sauce, and the quality of the appearance is impaired.

However, the present inventor has conducted intensive research in order to solve the above-mentioned problems in producing FRF molded products with complex shapes using the VI method. As a result, we succeeded in developing a completely new ily'1 method.

That is, the present invention includes a gel coat III and a core material. When manufacturing RF molded products using VI, a gel coat layer is formed on the mold 10,000, and the gel coat MII (
A layer of a mixture of curable resin and reinforcing fibers is formed on top of the JJ, then a core material is set, followed by a layered material of reinforcing fibers, after which the mold is closed, the curable resin is injected, and the curable resin is cured. The present invention relates to a method for manufacturing FRP molded products, which is characterized by the following:

Next, a case in which the method of the present invention is excessively used in molding the above-mentioned left side panel (2) will be explained with reference to the negative side.

FIG. 10 is a sectional view showing the state in which the left side panel (2) is molded, and (21 &) and (21b) are the lower and upper molds, respectively, of a mold made of FRP for the R/I method. be.

In the present invention, first, a curable resin for gel coat is sprayed onto the lower mold (21 m) and dried to form a gel coat layer (22).

Next, a mixture of curable resin and reinforcing fibers is applied onto the gel coat layer by hand lay-up method or spray-up method. After forming IjIga and setting the core material on the length, 1#1 of the mixture (
2) is precured. Next, after setting the reinforcing fibers, the upper mold (21b) is closed, and a curable resin is injected and hardened. After that, it is shaped and wrinkled to make a molded product as shown in Figure 11. In FIG. 11, (2) is an FRPil formed by injecting a curable resin.

In the present invention, a preform is set on a gel coat layer as shown in Figures 5 to 7 above,
Unlike the method of setting a core material on top of that, then setting a preform on top of that, and then injecting a curable resin and curing it all at once, the curable resin and reinforcing fibers are first formed on the gel coat layer. After pre-curing the shoelace of the mixture, the mixture layer (2) and the FIL are cured together with the FiLP layer (2) having the preform (2).
Each of PJllaIl is cured independently and the mixture layer @
Since the change in thickness due to curing shrinkage is almost constant in all parts, there is no risk that a step or an L will occur on the surface of the molded product. Therefore, there is no particular need to use a core material having a fin as the core material, and a core material formed by cutting can be used.

The core material with the final fins mentioned above needs to be molded using a special mold, which makes it expensive, and in order to improve the appeal with the Poi IJF 凰P@ which uses molded products. Sanding to remove surface dirt and after-curing to completely harden unreacted components are required, but cutting-processed core materials are inexpensive and do not require sanding or after-curing.

In addition, since the mixture layer formed on the gel coated shoe wheel according to the second aspect of the present invention is an FRP layer made of a homogeneous mixture of hardening resin and reinforcing fiber, one corner part as shown in Fig. 9 is made of resin. This prevents cracks in the gel coat layer from forming in rich areas to a certain extent.

Furthermore, in the present invention, since the core material is set by placing it on top of 1filH of the mixture, positioning is easy, and after setting the core material, the mixture layer is By pre-curing, the core material 124 is fixed, so the core material 124 is injected, and during curing, the core material 124 is not accustomed to shift, and the shift of the core material causes a resin-rich part and the occurrence of internal cracks due to this. Moreover, since it is easy to ensure the thickness of the FRP layer (mixture layer) between the gel coat layer (2) and the core material, the occurrence of sagging on the surface of the molded product can be easily prevented.

As described above, according to the present invention, it has a complicated shape,
This is extremely advantageous because rRPlffl-shaped products with good initial and aging quality can be manufactured at low cost and with high reliability.

In the present invention, none of the curable resins used in the conventional VI method are used, such as Gelco, JiiiCl, FiLP, etc. Saturated polyester! Mjlill
.

Examples include epoxy resins, urethane-polyester resins, epoxy-acrylate resins, diallyl phthalate-fats, and unsaturated polyester-fats are particularly preferred. The unsaturated polyester in 8 of the unsaturated polyester resins includes a polyhydric alcohol component such as ethylene gelcol and propylene glycol, and a polybasic acid component such as maleic anhydride fumaric acid and a mixture of these and 7-talol. Examples of crosslinking agents include styrene, etc., and curing agents include methyl ethyl ketone peroxide, pen, zoyl peroxide, cyclophenylene nonperoxide, and cumene hydrogen peroxide. You can open something like that. Others: cobalt naphthenate, manganese naphthenate, vanadium octoate,
Accelerators such as copper naphthenate may also be used.

Examples of reinforcing fibers used in the preform (c) include inorganic fibers such as glass fiber, carbon fiber, asbestos, ceramic fiber, and metal fiber, and organic fibers such as animal fiber and synthetic fiber, with glass fiber being particularly preferred. . These reinforcing fibers may be used in forms other than preforms such as wooden mats and various cloths.

As the curable resin used to form the gel coat layer, for example, an unsaturated polyester resin is used, and the unsaturated polyester includes polyhydric alcohol components such as ethylene glycol and propylene glycol, maleic anhydride, fumaric acid, and Ikuftal. Examples include those obtained by condensation polymerization with a polybasic acid component such as a mixture with an acid, and the same one as in the unsaturated polyester resin for FRP@@ can be used as the crosslinking 7-mer 1 curing agent. The thickness of the gel coat M*a is preferably about 0.3 to 0.6 am,
A molded product with a beautiful appearance can be obtained.

As the curable resin used for the mixture layer (2), the above-mentioned F
Something similar to that for the IP layer (2) is used. The same reinforcing fibers as those for the preform (2) are also used. The thickness of 1 m (2) of the mixture is F IL 7
Although it is related to the thickness of 7111@, it is preferably lam or more in order to sufficiently prevent appearance defects such as steps, sink marks, and blisters, and to ensure mechanical strength.

A resin foam is usually used as the core material, and examples of the resin foam include polyurethane foam and acrylic resin foam.

In the above, the method of the present invention has been explained by taking as an example a case where the method of the present invention is applicable to molding a left side spring 7J/(2) in an automobile having a rear podium that covers several brackets. The method of invention is similar to the light side panel (3),! J+#-7141, which can be used to mold parts such as hack doors (5), front roofs (6), and sunroofs (7), as well as other Hashiwa car parts, daily life items such as bathtubs, boats, etc. It can also be used for molding leisure goods.

Next, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Examples 2 to 35 A left side panel (2) having the shape shown in QK was manufactured.

Glass fiber # in preform mold! (Fiber diameter 1o#.

m fiber length approximately 50 mm) unsaturated polyester resin (ethylene glycol, maleic anhydride and phthalic anhydride).

Unsaturated polyester obtained from acid 100@(parts by weight,
A glass fiber preform was prepared by spraying the glass fiber with a glass fiber preform (same below), 30 parts of styrene, and 1 part of methyl ethyl ketone peroxide).

FRP lower W (21m) unsaturated polyester resin (
(consisting of 100 parts of unsaturated polyester obtained from ethylene glycol, maleic anhydride and isophthalic acid, 30 parts of styrene, 1 part of methyl ethyl ketone peroxide, 0.5 part of cobalt naphthenate). !
! A gel coat layer (2) having a thickness of 0.3 mm was formed.

Contains glass fiber on top of the gel coat layer (2)! 130111 was coated with a small amount of unsaturated polyester resin using the hand lay-up method so that the thickness after curing was 11, and then a core material made by cutting hard polyurethane foam was placed on top of it. The mixture layer (2) was precured at 5000 for 20 minutes.

Next, the preform (2) is set and the lower mold (21
m) and the upper mold (21b) are closed, and unsaturated polyester resin (same as that used for making the preform) is injected through the injection hole at an injection pressure of (S kg/e-), and after 30 minutes, it is separated. It was molded and after-cured under the conditions of 70°1OX3hr to obtain an FRP left side panel (2).

No sink marks, steps, or cracks were observed in the resulting product.

Comparative Example A preform (produced in the same manner as preform (2)), a core material O4, and a preform (2) were set on top of the gel coat layer (to) in this order, and a curable resin was injected. A left side panel (2) was produced in the same manner as in the example except that the left side panel (2) was cured.

In the obtained product 2, a step was observed on the surface of the core material (2), and a crank was observed on the gel coat layer at a part of the corner.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the body of an automobile that has a loading platform at the rear of the vehicle body and a rear body that respects this loading platform, Figures 2 and 3 are views of the Y-O PI111 left side panel from the front and back sides, respectively. Perspective views and s4 figures are from 2nd to
Figure 3 is an enlarged sectional view along the line (Zen-(Xuan), and Figure S is a partial cross-section II (No. 4
(corresponding to an enlarged view of circle (4) in the figure), No. 611 is an explanatory diagram explaining the cause of the step, s7E is a partial cross-sectional view showing a state where sink marks have occurred on the surface of the FIP molded product, Fig. 8 9E is a partial cross-sectional view of a L-P molded product using L-shaped core material as the core material. (B)
Fig. 10 is a partial sectional view showing a state in which an FRF molded product is molded by the method of the present invention, and Fig. 11 is an IFRF molded product obtained by the method of the present invention. FIG. (Main figures and symbols in the drawing) (21m) : Lower mold (Plan 1b) : Upper mold (2) Nigel coat layer @ : Mixture layer c141 : Core material @ Nibri form @ : IF'BP layer (Fig. 1, Fig. 2) Figure 3-1 2: Figure 4 ′ Figure 5 O 6 yen off figure ~ Age 8 Figure 1 1 Figure 22 23

Claims (1)

[Claims] 1. When manufacturing a fiber-reinforced plastic molded product having a gel coat layer and a core material by the resin injection method, a gel coat layer is formed on one side of the mold, and a mixture of a curable resin and reinforcing fiber is applied on the gel coat layer. A method for producing a fiber-reinforced plastic molded product, which is characterized by forming fat, then setting a core material, setting reinforcing fiber footwear, then closing the mold, injecting a curable resin, and allowing it to harden. .