JPH0724922A - Manufacture of pultrusion molded item - Google Patents

Abstract

PURPOSE:To provide a method for manufacture of a thick wall pultruded molded item wherein a thickness of the molded item exceeds 10mm, and it is free from occurrence of interlayer separation, crack, and warpage which are caused by residual stress. CONSTITUTION:A central layer forming material 14 wherein reinforced fiber 11 is impregnated with setting resin 12 for forming of a central layer of a quick setting speed is conducted to a pultrusion molding metal die 15. Reinforced fiber 16 for forming of a front layer is laminated on an outer periphery of the central layer forming material 14 and conducted to the pultrusion molding metal die 15. The reinforced fiber 16 is impregnated with a front layer forming setting resin 19 in the pultrusion molding metal die 15 to make a front layer forming material 20. The central layer forming material 14 and the front layer forming material 20 are heated with the pultrusion molding metal die 15 while passing therethrough, shaped, set, continuously pulled out with a puller 21, and a pultrusion molded item wherein the front layer is laminated on the outer peripheral surface of the central layer to be integrated therewith, is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pultruded molded product having a large thickness such that the molded product has a thickness of, for example, more than 10 mm.

[0002]

2. Description of the Related Art Conventionally, when a reinforced fiber impregnated with a curable resin is drawn through a pultrusion molding die, that is, when a molded article is manufactured by a so-called pultrusion molding method, the molded article withdrawn from the die is exposed to the outside air or a pulling machine. There is a problem in that, when the grip portion is touched and rapidly cooled, residual stress is generated inside and delamination occurs or cracks occur, leading to deterioration in physical properties.

In view of this point, for example, JP-A-62-18
As described in Japanese Patent No. 7019, there has been proposed a method of controlling the pull-out gripping portion to a temperature that does not cause a rapid temperature drop in the molded product.

[0004]

However, in the case of molding a thin-walled pultruded product by the above method, when the curable resin-impregnated reinforcing fiber passes through the mold, the curing of the resin occurs in the thickness direction. Although it does not cause a problem because it progresses almost at the same time, as the thickness of the molded product increases, the heat supplied to the mold progresses from the surface part of the molded product toward the center part, so its curing also moves from the surface to the center. Proceed in sequence toward each other.

Therefore, in a thick-walled molded product, a time difference occurs in the thickness direction at the time of shrinkage due to a curing reaction in the molded product, and remains as internal stress in the molded product, resulting in delamination, cracks, warpage, etc. There is a problem that it appears as.

The present invention solves the above-mentioned conventional problems, for example, the thickness of a molded product exceeds 10 mm, and moreover, the drawing of a thick wall without the occurrence of delamination, cracks and warpage due to residual stress. It is an object to provide a method for producing a molded product.

[0007]

According to the present invention, a center layer forming material composed of a curable resin-impregnated reinforcing fiber is introduced into a pultrusion molding die, and a reinforcing fiber for forming a surface layer is superposed on the outer periphery thereof. In the pultrusion mold, the reinforcing fibers for forming the surface layer are impregnated with the curable resin for forming the surface layer, which has a relatively slower curing speed than the curable resin in the material for forming the center layer. As the surface layer forming material, the center layer forming material and the surface layer forming material are shaped and cured while passing through the pultrusion molding die, and the surface layer is integrally laminated on the outer peripheral surface of the center layer. Is a method for producing a pultruded product, in which P is continuously drawn.

In the present invention, examples of the reinforcing fiber forming the material for forming the center layer and the material for forming the surface layer include roving of glass fiber, organic fiber, carbon fiber, etc., cloth, continuous strand mat, chopped strand mat, etc. Among them, roving of glass fiber and continuous strand mat are preferably used.

In the present invention, examples of the base resin of the surface layer forming material and the curable resin forming the surface layer forming material include unsaturated polyester resin, epoxy resin,
Vinyl ester resin, phenol resin, etc. are used.

In the present invention, as the curable resin forming the surface layer forming material, it is necessary to use a curable resin having a relatively slower curing speed than the curable resin in the center layer forming material. Since this relationship is relative,
The curable resin in the material for forming the center layer may be set to have a faster curing rate than the curable resin for forming the material for forming the surface layer.

The curable resin forming the surface layer forming material is
As a method of setting the curing speed to be relatively slower than that of the curable resin in the material for forming the center layer, the following four types of methods can be mentioned, but each method may be used independently. Alternatively, two or more methods may be used in combination.

The first method is a method in which the polymerization inhibitor is added to the curable resin forming the surface layer forming material and the polymerization inhibitor is not added to the curable resin forming the center layer forming material.

The amount of the polymerization inhibitor added is selected according to the thickness of the molded product to be obtained, but is preferably 0.001 to 1.0 part by weight with respect to 100 parts by weight of the curable resin. When the addition amount is less than 0.001 part by weight, the curing rate of the curable resin forming the surface layer forming material is not significantly different from that of the curable resin forming the center layer forming material, and the curability of forming the surface layer forming material. The effect of delaying the curing of the resin cannot be expected, and conversely, when it exceeds 1.0 part by weight, the curing of the curable resin forming the surface layer forming material becomes extremely slow,
The surface layer may be poorly cured, and the surface properties of the pultrusion product obtained may be impaired.

As the polymerization inhibitor, for example, generally known polymerization inhibitors such as hydroquinone, benzoquinone, pt-butylcatechol, chloranil, m-dinitrobenzene, nitrobenzene, p-phenylamine and sulfur are used. It

In the second method, the addition amount of the curing catalyst added to the curable resin forming the center layer forming material is the addition amount of the curing catalyst added to the curable resin forming the corresponding surface layer forming material. Is a way to do more.

The ratio of the addition amount of the curing catalyst added to the curable resin forming the center layer forming material to the addition amount 1 of the curing catalyst added to the curable resin forming the surface layer forming material is 1.1 to. A value of 5 is suitable. When the ratio of the added amount is less than 1.1, the effect of accelerating the curing of the curable resin that forms the material for forming the center layer cannot be expected. Curing of the curable resin forming the layer forming material becomes rapid, which causes cracks to occur inside the pultrusion product obtained.

As the curing catalyst, bis- (4-t-butylcyclohexyl) peroxydicarbonate, benzoyl peroxide, t-butyl peroctoate, methyl ethyl ketone peroxide, t-butyl perbenzoate, dicumyl peroxide, t Commonly known organic peroxides such as -butylcumyl peroxide, and commonly known azo compounds such as azoisobutyronitrile and azobisvaleronitrile are used.

In the third method, as a curing catalyst added to the curable resin forming the surface layer forming material, the difference in decomposition temperature is higher than that of the curing catalyst added to the curable resin forming the center layer forming material. This is a method of using a material having a temperature higher than 3 ° C.
When the difference in decomposition temperature is less than 3 ° C., the curing rate of the curable resin forming the surface layer forming material is not so different from that of the curable resin forming the center layer forming material, and the curable resin forming the surface layer forming material. The effect of delaying the curing of can not be expected.

An example of a combination of a curing catalyst added to the curable resin forming the surface layer forming material and a curing catalyst added to the curable resin forming the center layer forming material is, for example, t-butylperoxy. ─2-Ethylhexanoate (decomposition temperature 70 ℃) and bis (4-t-butylcyclohexyl) peroxydicarbonate (decomposition temperature 50 ℃)
And the like.

The fourth method is the addition amount of the curing accelerator added to the curable resin forming the center layer forming material with respect to the addition amount of the curing accelerator added to the curable resin forming the surface layer forming material. Is a way to increase. The ratio of the addition amount of the curing accelerator added to the curable resin forming the central layer forming material to the addition amount 1 of the curing accelerator added to the curable resin forming the surface layer forming material is 1.1 to 5 Is preferred.

When the ratio of the addition amount of the curing accelerator is less than 1.1, the effect of accelerating the curing of the curable resin forming the center layer forming material cannot be expected, and conversely,
When it exceeds 5, the hardening of the curable resin forming the center layer forming material becomes rapid, causing cracks to occur inside the obtained molded product. Incidentally, the curing accelerator may be added to the curable resin forming the center layer forming material without adding the curing accelerator to the curable resin forming the surface layer forming material.

As the curing accelerator, for example, commonly known organic acid salts of metals such as cobalt naphthenate, cobalt octenoate, cobalt acetate and manganese acetate are used.

[0023]

The method for producing a pultruded article of the present invention is such that a core layer forming material composed of a curable resin-impregnated reinforcing fiber is introduced into a pultrusion mold and is reinforced for forming a surface layer by being superposed on the outer periphery thereof. Introducing fibers into the pultrusion mold, impregnating the reinforcing fibers for surface layer formation with the curable resin for surface layer formation, which has a relatively slower curing speed than the curable resin in the center layer formation material. Then, the surface layer forming material is formed, the center layer forming material and the surface layer forming material are shaped and cured while passing through the drawing mold, and the surface layer is integrally laminated on the outer peripheral surface of the center layer. By pulling this continuously, the thickness is 10m
Even if the molded product has a thickness of more than m, even if there is a time lag between the surface layer and the central layer of the molded product, the curing reaction of the curable resin Can be adjusted so that they proceed in the surface layer and the central layer almost at the same time, so that it is possible to obtain a thick-walled pultruded product which is free from delamination, cracks and warpage due to residual stress.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view for explaining the steps of an example of the method for producing a pultruded product of the present invention. By passing the reinforcing fiber 11 such as glass roving for forming the center layer through the impregnation tank 13 containing the curable resin 12 for forming the center layer having a high curing rate, the reinforcing fiber 11 is impregnated with the curable resin 12. The center layer forming material 14 is formed, and this is introduced into the pultrusion molding die 15. Further, the reinforcing fibers 16 for forming the surface layer are introduced into the pultrusion molding die 15 so as to overlap the outer periphery of the material 14 for forming the center layer.

In the pultrusion molding die 15, a groove 151 is provided along the circumferential direction on the inner peripheral surface of the die surface near the inlet, and the groove 151 is formed by an external resin tank 17. The curable resin 19 for forming the surface layer can be supplied through the pipe 18. Then, in the pultrusion molding die 15, the surface layer-forming reinforcing resin 16 is incorporated into the surface layer-forming curable resin 19.
Is pressed and impregnated to obtain the surface layer forming material 20.

A heating means (not shown) is provided on the outlet side of the pultrusion mold 15. The center layer forming material 14 and the surface layer forming material 20 are heated by a heating means to be shaped and cured while passing through the pultrusion molding die 15 and continuously drawn by a take-up device 21 and a cutting device. 22
And cut it to an appropriate length by using the center layer 3 as shown in FIG.
A pultruded product 3 is obtained by integrally curing the surface layer 32 on the outer peripheral surface of 1.

Examples 1 to 4 and Comparative Example By the process described with reference to FIG. 1, as shown in FIG.
A pultruded product having a width of 10 cm and a thickness of 2 cm was obtained. As the reinforcing fibers 11 for forming the central layer, 250 glass rovings ("4450" manufactured by Asahi Fiber Co., Ltd.) were used. As reinforcing fibers for forming the surface layer, 250 pieces of glass roving (manufactured by Asahi Fiber Co., Ltd., “4450”) and continuous matte (manufactured by Asahi Fiber Co., Ltd., “450”) were used for 5 parts by weight per 95 parts by weight of glass roving. Used in part ratio.

As the curable resin 12 for forming the central layer and the curable resin 19 for forming the surface layer, those shown in Table 1 were used in the addition amounts shown in Table 1. In the case of Example 1, hydroquinone, which is a polymerization inhibitor, was added to the curable resin 19 for forming the surface layer to slow the curing rate.

In the case of Example 2, the addition amount of the curing catalyst in the curable resin 12 for forming the central layer is made larger than the addition amount of the curing catalyst in the curable resin 19 for forming the surface layer. The curing speed of the curable resin 12 for forming the central layer was increased. In the case of Example 3, a curing catalyst in the surface layer-forming curable resin 19 having a higher decomposition temperature than that of the curing catalyst in the center layer-forming curable resin 19 is used to form the surface layer. The curing speed of the curable resin 19 was slowed down.

In the case of Example 4, a curing accelerator was added only to the curable resin 12 for forming the central layer to increase the curing speed. In the case of the comparative example, the curable resin 12 for forming the central layer and the curable resin 19 for forming the surface layer have the same composition and addition amount.

Further, as the pultrusion molding die 15, a total length of 10
00 mm and the concave groove 151 were provided at the position of the mold surface 100 mm from the inlet, and the temperature distribution used was 100 ° C. to 150 ° C. The injection amount of the curable resin for forming the surface layer is 300
The injection pressure was 0 ml / min, and the injection pressure was 3.0 kgf / cm ² .
The take-up speed of the take-up device 21 was 50 cm / min.

With respect to the pultruded products obtained in Examples 1 to 4 and Comparative Example, the bending strength and the bending elastic modulus were measured, and the appearance was evaluated. The results are shown in Table 1.
Regarding bending strength and bending modulus, JIS K7
It was measured according to 055. The appearance was evaluated by observing the presence or absence of delamination, cracks and warpage of the obtained pultrusion molded product.

[0033]

[Table 1]

As is clear from Table 1, in each of Examples 1 to 4 of the present invention, the bending strength and the bending elastic modulus were excellent, and delamination, cracking and warpage did not occur. On the other hand, in the case of Comparative Example, the flexural strength and flexural modulus were low, and delamination and cracking were observed.

[0035]

Since the pultrusion molded article manufacturing method of the present invention is configured as described above, the molded article has a thickness of 10 mm.
It is possible to obtain a thick-walled pultruded product which exceeds the above range and is free from delamination, cracks and warpage due to residual stress.

[0036]

[Brief description of drawings]

FIG. 1 is a partially cutaway front view illustrating a process of an example of a method for manufacturing a pultrusion molded product of the present invention.

FIG. 2 is a cross-sectional view showing an example of a pultrusion molded product obtained by the method for manufacturing a pultrusion molded product of the present invention.

[Explanation of symbols]

 3 Pulsation Molded Products 11, 16 Reinforcing Fibers 12, 19 Curable Resin 13 Impregnation Tank 14 Center Layer Forming Material 15 Pulsation Molding Mold 17 Resin Tank 20 Surface Layer Forming Material 21 Pulling Device 22 Cutting Device 31 Center Layer 32 Surface Layer 151 Groove

Claims (1)

[Claims] 1. A center layer forming material comprising a curable resin-impregnated reinforcing fiber is introduced into a pultrusion mold, and
Introducing the reinforcing fibers for forming the surface layer on the outer periphery thereof, and in the pultrusion mold, the reinforcing fibers for forming the surface layer have a relatively higher curing rate than the curable resin in the center layer forming material. A slow surface layer forming curable resin is impregnated to form a surface layer forming material, and the center layer forming material and the surface layer forming material are shaped and cured while passing through a pultrusion molding die to form the center layer. A method for producing a pultruded product, characterized in that a surface layer is integrally laminated on the outer peripheral surface and is continuously drawn out.