JPH07251460A - Production of fiber reinforced unsaturated polyester resin molding - Google Patents

Abstract

PURPOSE:To produce a fiber reinforced unsaturated polyester resin molding excellent in strength and surface accuracy. CONSTITUTION:An unsaturated polyester resin compounded with a low temp. curing agent (A) and a high temp. curing agent (B) different from each other in radical generating temp. by 20 deg.C or higher is infiltrated into continuous reinforcing fiber bundles F. The impregnated reinforcing fiber bundles F are introduced into a semi-curing heating mold 7 to be heated to the temp. range from the radical generating temp. of the low temp. curing agent to below the radical generating temp. of the high temp. curing agent to be brought to a semi-cured state. This semi-cured unsaturated polyester resin impregnated reinforcing fiber layer is sent into the gap between steel belt presses 9, 10 to be shaped under pressure and heated to the radical generating temp. of the high temp. curing agent at the same time to be finally cured.

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 fiber-reinforced unsaturated polyester resin molding having excellent strength and surface accuracy.

[0002]

2. Description of the Related Art Conventionally, when continuously molding a continuous fiber-reinforced thermosetting resin molded article, various methods have been used to control the curing mode and shaping timing of the thermosetting resin. For example, in JP-A-55-37351, two or more kinds of curing agents having different curing rates are used in a mixed state, and a matrix resin is cured by a combination of curing in a mold and subsequent curing by heat treatment. The method of performing the method is described in JP-A-48-
No. 75674 describes a method in which a gel of resin is first formed in the die and the material emerges from the die before the maximum heat buildup of the resin and is also disclosed in JP-A-4-105923.
The publication describes a method in which a molded product is drawn out from a drawing die in a semi-cured state, and then the molded product is passed through an after-cure furnace while being received by a conveyor from the upper and lower surfaces to completely cure the molded product.

[0003]

However, in the above manufacturing method, the forming pressure when dispersing two or more curing agents is substantially the same or is low when decomposing the curing agent on the high temperature side. There is no pressure (normal pressure), that is, the pressure is released.

Therefore, when the curing on the low temperature side is insufficient, the surface is warped or deformed due to pressure release, and it is impossible to correct it at low pressure (normal pressure) during high temperature curing. . Further, if the hardening is advanced to some extent at a low temperature and the hardening is advanced to such an extent that there is no case described above, the hardening on the high temperature side becomes practically useless. In addition, if a high pressure is applied during low temperature curing, the resin has a low viscosity, so that only the resin flows and the resin / fiber ratio becomes non-uniform.

The present invention solves the above-mentioned conventional problems, has a uniform resin / fiber ratio, is excellent in strength, and is excellent in surface accuracy without surface roughness or deformation, and is a fiber-reinforced unsaturated polyester resin. The purpose of the present invention is to provide a method for producing a molded product.

[0006]

According to the present invention, a continuous reinforcing fiber is prepared by blending an unsaturated polyester resin with a low temperature side curing agent (A) and a high temperature side curing agent (B) having radical generation temperatures different by 20 ° C. or more. And then heated to below the radical generation temperature of the high temperature side curing agent above the radical generation temperature of the low temperature side curing agent to form a semi-cured state, and pressurize the unsaturated polyester resin reinforced fiber in this semi-cured state. It is a method for producing a fiber-reinforced unsaturated polyester resin molded body which is heated at a temperature higher than the radical generation temperature of the curing agent on the high temperature side to be finally cured while being shaped.

In the present invention, as the unsaturated polyester resin, all commonly used unsaturated polyester resins are used. That is, it is one obtained by heating ester copolymerization of glycols and unsaturated polybasic acid or saturated polybasic acid alone, or one obtained by dissolving the above unsaturated polyester resin in copolymerizable monomers.

As the unsaturated polybasic acid, for example, maleic anhydride, fumaric acid, itaconic acid, citraconic acid and the like are used. Examples of the saturated polybasic acid include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, adipic acid and sebacic acid.

Examples of glycols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, hydrogen. Bisphenol A, bisphenol A propyleneoxy adduct, dibromoneopentyl glycol, pentaerythritol diallyl ether, allyl glycidyl ether and the like are used.

Examples of the copolymerizable monomers capable of dissolving the unsaturated polyester resin include styrene, vinyltoluene, α-methylstyrene, methyl methacrylate, vinyl acetate, allyl phthalate, diallyl isophthalate, triallyl isocyanurate, Diallyl tetrabrom phthalate, phenoxyethyl acrylate, 1,6
-Hexanediol diacrylate, trimethylolpropane acrylate, 2-hydroxyethyl acrylate, etc. are used. The mixing ratio of the copolymerizable monomers is
Usually, it is 20 to 60% by weight of the unsaturated polyester resin.

If desired, the unsaturated polyester resin may contain additives such as stabilizers, lubricants, processing aids, plasticizers and colorants, and fillers such as calcium carbonate and metal oxides. May be.

In the present invention, the radical generation temperature of 2 is used.
Low temperature side curing agent (A) and high temperature side curing agent (B) different by 0 ° C or more
Is used. Here, the radical generation temperature refers to a temperature at which the half-life is 10 hours or less. Therefore, as the low temperature side curing agent (A) and the high temperature side curing agent (B), peroxides having different 10-hour half-life temperatures of 20 ° C. or more are used. When this 10-hour half-life temperature difference is less than 20 ° C., the temperature control becomes delicate, and the high temperature side curing agent (B) is considerably decomposed when the low temperature side curing agent (A) is decomposed, so it is necessary to use a plurality of curing agents. Is less.

The 10-hour half-life temperatures of the low temperature side curing agent (A) and the high temperature side curing agent (B) are 20 ° C. or higher and 190 ° C. for both the low temperature side curing agent (A) and the high temperature side curing agent (B). The following is preferable. If the temperature is lower than 20 ° C, a refrigerator and a manufacturing apparatus equipped with a special cooling device are required, and an abnormal reaction is apt to occur, which makes the production very dangerous. In addition to being necessary and uneconomical, voids, cracks and the like occur in the molded product obtained by volatilizing the copolymerizable monomer in the unsaturated polyester resin, and the molding performance is deteriorated.

Low temperature side curing agent (A) and high temperature side curing agent (B)
When the 10-hour half-life temperature of the above is 20 ° C or more and 190 ° C or less, the 10-hour half-life temperature difference between the two is different by 20 ° C or more. Therefore, the low-temperature side curing agent (A) has a 10-hour half-life. The temperature is 20 to 170 ° C., the high temperature side curing agent (B) is 10
The time half-life temperature will be selected within the range of 40 to 190 ° C.

Low temperature side curing agent (A) and high temperature side curing agent (B)
Examples of the combination of are as follows. (1) (A): t-butylperoxy (2-ethylhexanoate) (10-hour half-life temperature 72.5 ° C) (B): t-butylperbenzoate (10-hour half-life temperature 104 ° C) ( 2) (A): Benzoyl peroxide (10-hour half-life temperature of 74 ° C) (B): Dicumyl peroxide (10-hour half-life temperature of 117 ° C)

(3) (A): t-butylperoxyisopropyl carbonate (10-hour half-life temperature of 97 ° C.) (B): di-t-butylperoxide (10-hour half-life of 126 ° C.) (4) (A ): Methyl ethyl ketone peroxide (10
(Time half-life temperature 105 ° C) (B): t-butyl hydroperoxide (10-hour half-life temperature 171 ° C)

(5) (A): Cyclohexanone peroxide (10-hour half-life temperature 90 ° C.) (B): Diisopropylbenzene hydroperoxide (10-hour half-life temperature 150 ° C.) (6) (A): 2,2 -Bis (4,4-di-t-butylperoxycyclohexyl) propane (10-hour half-life temperature 92 ° C) (B): t-butylcumyl peroxide (10-hour half-life temperature 121 ° C)

(7) (A): t-butylperoxypivalate (10-hour half-life temperature 56 ° C.) (B): 2,2-di- (t-butylperoxy) -butane (10-hour half-life) (Temperature 102 ° C) (8) (A): methyl isobutyl ketone peroxide (10-hour half-life temperature 88 ° C) (B): 2,4,4-trimethylpentyl-2-hydroperoxide (10-hour half-life temperature 135) ℃)

(9) (A): Methylcyclohexanone peroxide (10-hour half-life temperature 96 ° C) (B): Acetylacetone peroxide (10-hour half-life temperature 130 ° C) (10) (A): p-cyclobenzoyl Peroxide (1
(0-hour half-life temperature 75 ° C) (B): tris- (t-butylperoxy) triazine (10-hour half-life temperature 110 ° C)

The compounding amount of the low temperature side curing agent (A) is preferably 0.03 to 2 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin. If the blending amount is less than 0.03 parts by weight, it takes time to reach a semi-cured state, and the production is difficult. If the blending amount exceeds 2 parts by weight, final curing is effected only with the low temperature side curing agent.

The semi-cured state of the unsaturated polyester resin is
The proportion of the copolymerizable monomer polymerized by polymerization is 0.
It is preferably from 01 to 25%. When the proportion of polymerized is less than 0.01%, there is no effect of semi-curing in the liquid state, and when it exceeds 25%, the resin hardness becomes high and post-forming becomes difficult.

The total amount of the low temperature side curing agent (A) and the high temperature side curing agent (B) is the same as the amount of the ordinary unsaturated polyester resin, that is, unsaturated polyester resin 1
0.5 to 5 parts by weight is preferable with respect to 00 parts by weight.

In the present invention, as the reinforcing fiber, a fiber stable at the temperature of the curing step of the unsaturated polyester resin used is used, and for example, glass fiber, carbon fiber,
Examples thereof include silicon / titanium / carbon fibers, boron fibers, fine metal fibers, and organic fibers such as aramid fibers, econol fibers, polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, and vinylon fibers. As the reinforcing fiber, a monofilament having a diameter of 1 to 50 μm is preferably used.

The form of the reinforcing fiber includes a roving in which a large number of filaments are bundled, a continuous strand mat in which the strands of the filament bundle are two-dimensionally randomly arranged and bonded with a binder, and the strand bundle is arranged in a circle (swirl). Then, the swirl mat and the roving which were combined with the needle punch were plain woven and satin woven,
A roving cloth or the like is used alone or in combination.

The compounding amount of the reinforcing fiber is preferably 50 to 500 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin. If the blending amount is less than 50 parts by weight, the mechanical strength of the obtained molded article is insufficient, and if it exceeds 500 parts by weight,
It is difficult to obtain a molded product in which the reinforced resin is uniformly dispersed in the unsaturated polyester resin, and the occurrence of voids or the like significantly reduces the strength of the resulting molded product.

In the present invention, the semi-cured polyester resin reinforced fiber is heated and heated at a temperature higher than the radical generation temperature of the curing agent on the high temperature side to be finally cured, at the same time as heating and heating to high temperature. A method, specifically, a method of shaping by a shaping jig heated to a temperature higher than the radical generation temperature of the high temperature side curing agent (A) is adopted.

As the method for infiltrating the unsaturated polyester resin into the continuous reinforcing fiber, the continuous reinforcing fiber is dipped in a tank filled with the unsaturated polyester resin so as to pass therethrough, and the mold to which the reinforcing fiber is supplied. A commonly used method such as a method of injecting an unsaturated polyester resin into the above can be appropriately adopted.

The present invention will be described below with reference to the drawings.
FIG. 1 is a front view illustrating the steps of an example of the method for producing a fiber-reinforced unsaturated polyester resin molded product of the present invention together with an apparatus.

First, the apparatus will be described. This apparatus is configured as follows. As shown in FIG. 1, this device comprises a roving stand 1 in which a plurality of reinforcing fiber bundles F aligned in one direction are arranged, and a continuous strand mat f arranged randomly in a plane.
And a rewinding roll 2 for rewinding. still,
In FIG. 1, only two reinforcing fiber bundles F and continuous reinforcing fiber mats f are shown for the sake of convenience, but in reality, a large number of reinforcing fiber bundles and continuous reinforcing fiber mats are used in parallel as needed. To be

This apparatus also comprises a tank 3 filled with an unsaturated polyester resin liquid, a guide 4, a dipper 4 ', an infeed 5 for guiding and taking out the reinforcing fiber bundle F into the tank 3, and a reinforcement. The fiber bundle F and the continuous strand mat f are provided with a drawing die 6 having a scraper function for adjusting the amount of the unsaturated polyester resin liquid adhering to the constant amount and a function for adjusting the tension of the entire system. .

In this apparatus, the unsaturated polyester resin-impregnated reinforcing fibers that have passed through the drawing die 6 are heated to a temperature above the decomposition temperature of the low temperature side curing agent (A) and below the decomposition temperature of the high temperature side curing agent (B). Heating die 7 and a take-up roll 8 for taking up the semi-cured unsaturated polyester resin infiltrated reinforcing fiber,
It is provided with a pair of upper and lower steel belt presses 9 and 10 heated above the decomposition temperature of the high temperature side curing agent (B), and a cutter 11 for cutting the molded body.

Next, an example of the method for producing the fiber-reinforced unsaturated polyester resin molded product of the present invention using the above-mentioned apparatus will be described with reference to FIG. As shown in FIG. 1, the reinforced fiber bundle F and the continuous strand mat f are fed from the roving stand 1 and the rewinding roll 2 by driving the take-up roll 8, and the unsaturated polyester resin liquid is discharged by the guide 4 and the dipper 4 ′. The unsaturated polyester resin liquid is made to penetrate into the reinforcing fiber by passing through the filled tank 3.

The unsaturated polyester resin-impregnated reinforcing fiber obtained by passing through the tank 3 is introduced into the drawing die 6 via the infeed 5. By adjusting the clearance of the drawing die 6, the unsaturated polyester resin liquid excessively attached to the unsaturated polyester resin infiltrated reinforcing fibers is squeezed out,
The infiltration amount is adjusted to a constant amount.

The unsaturated polyester resin-impregnated reinforcing fiber is introduced into the heating mold 7 for semi-curing with a constant tension applied by the drawing mold 6, and the temperature is higher than the decomposition temperature of the curing agent (A) on the low temperature side. Heating below the decomposition temperature of the side curing agent (B),
Semi-cure the unsaturated polyester resin.

The obtained semi-cured unsaturated polyester resin-impregnated reinforcing fiber is passed through a take-up roll 8 and between a pair of upper and lower steel belt presses 9 and 10 heated above the decomposition temperature of the high temperature side curing agent (B). It is fed, shaped, and finally cured, and it is led out between the steel belt presses 9 and 10 and cut to a suitable length with a cutter 11,
A fiber-reinforced unsaturated polyester resin molding is obtained.

[0036]

According to the method for producing a fiber-reinforced unsaturated polyester resin molding of the present invention, a low temperature side curing agent (A) and a high temperature side curing agent (B) having radical generation temperatures different by 20 ° C. or more are blended with an unsaturated polyester resin. After being infiltrated into the continuous reinforcing fiber, it is heated to a temperature above the radical generation temperature of the low temperature side curing agent and below the radical generation temperature of the high temperature side curing agent to form a semi-cured state. By shaping the reinforcing fiber under pressure and at the same time heating it above the radical generation temperature of the curing agent on the high temperature side and finally curing it, the unsaturated polyester resin reinforcing fiber is shaped with a high pressure after it is in a semi-cured state. During molding, it is possible to apply sufficient internal pressure while maintaining the resin / fiber ratio in a uniform state, and it is excellent in strength. It is possible to obtain the sum polyester resin molding.

[0037]

EXAMPLES The present invention will be described below with reference to examples. Example 1 As an unsaturated polyester resin, a terpolymer of maleic anhydride, neopentyl glycol, and phthalic anhydride was added.
Styrene added so as to be 40% by weight of the whole was used.

To 100 parts by weight of unsaturated polyester resin,
As the low temperature side curing agent (A), t-butylperoxy (2
-Ethyl hexanoate) (10-hour half-life temperature 72.
5 ° C.) 0.7 parts by weight, and as the high temperature side curing agent (B), t
An unsaturated polyester resin composition was prepared by adding 1 part by weight of butyl peroxybenzoate (10-hour half-life temperature 104 ° C.).

As the reinforcing fiber bundle F, 50 pieces of 4450 tex glass fiber roving, and as the continuous strand mat f, a glass fiber continuous strand mat having a basis weight of 450 g / m ² was used. I used one.

According to the process described with reference to FIG. 1, the reinforcing fiber bundle F and the continuous strand mat f are
The unsaturated polyester resin composition was passed through the tank 3 filled with the unsaturated polyester resin composition, and the infiltration amount was adjusted by the drawing die 6 so that the total glass fiber content was adjusted to 40% by weight. Fibers were prepared.

The unsaturated polyester resin-impregnated reinforcing fiber is passed through the heating mold 7 heated to 98 ° C. to obtain a semi-cured unsaturated polyester resin-impregnated reinforcing fiber,
This was sent through a take-up machine 8 between a pair of upper and lower steel belt presses 9 and 10 moving at a speed of 2 m / min and a temperature of 1
After shaping and final curing under the conditions of 45 ° C. and a compressive force of 2.5 kg / cm ² , a flat plate-shaped molded body having a thickness of 3 mm and a width of 100 mm was formed from the tips of the pair of upper and lower steel belt presses 9 and 10. Obtained.

The surface smoothness of the obtained molded product was
10-point average roughness (Rz) according to JIS K5400
Was measured. The results are shown in Table 1.

Example 2 As an unsaturated polyester resin, a terpolymer of maleic anhydride, propylene glycol and isophthalic acid was mixed with styrene and diallyl phthalate at a weight ratio of 1: 1 to prepare a mixed monomer as a whole. Unsaturated polyester resin 100, which was added so as to be 45% by weight
0.6 parts by weight of benzoyl peroxide (10-hour half-life temperature 74 ° C.) as a low-temperature side curing agent (A) and dicumyl peroxide (10-hour half-life period) as a high-temperature side curing agent (B). (Temperature 104 ° C.) 1.2 parts by weight was added, and a flat plate-shaped molded product similar to that of Example 1 was obtained in the same manner as in Example 1 except that the unsaturated polyester resin composition was used. The surface smoothness of the obtained molded body was measured in the same manner as in Example 1. The results are also shown in Table 1.

Comparative Example 1 An unsaturated polyester resin composition obtained by adding 1.7 parts by weight of t-butylperoxybenzoate alone as a curing agent to 100 parts by weight of an unsaturated polyester resin was used.
A flat plate-shaped molded product similar to that of Example 1 was obtained in the same manner as in Example 1 except that the temperature was set to room temperature (25 ° C.) without heating by the heating mold 7. The surface smoothness of the obtained molded body was measured in the same manner as in Example 1. The results are also shown in Table 1.

Comparative Example 2 An unsaturated polyester resin composition prepared by adding 1.8 parts by weight of benzoyl peroxide alone as a curing agent to 100 parts by weight of the unsaturated polyester resin of Example 2 was used. The heating was 145 ° C., and the compressive force between the pair of upper and lower steel belt presses 9 and 10 was 0.
A flat plate-shaped molded product similar to that of Example 1 was obtained in the same manner as in Example 1 except that the amount was ² kg / cm ² . The surface smoothness of the obtained molded body was measured in the same manner as in Example 1. The results are also shown in Table 1.

[0046]

[Table 1]

As is clear from Table 1, in the cases of Examples 1 and 2, the surface smoothness was excellent, whereas in the cases of Comparative Examples 1 and 2, the surface smoothness was excellent. Is inferior.

[0048]

Since the method for producing a fiber-reinforced unsaturated polyester resin molded article of the present invention is configured as described above, it is possible to obtain a fiber-reinforced unsaturated polyester resin molded article excellent in strength and surface accuracy. it can.

[0049]

[Brief description of drawings]

FIG. 1 is a front view illustrating a process of an example of a method for producing a fiber-reinforced unsaturated polyester resin molded product of the present invention together with an apparatus.

[Explanation of symbols]

 F Reinforced fiber bundle f Mat 1 Roving stand 2 Rewinding roll 3 Tank 4 Guide 4'Dipper 5 Infeed 6 Drawing die 7 Semi-curing heating die 8 Take-up roll 9,10 Endless steel belt press 11 Cutter

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Claims (1)

[Claims] 1. An unsaturated polyester resin containing a low-temperature side curing agent (A) and a high-temperature side curing agent (B) different in radical generation temperature of 20 ° C. or more is mixed into a continuous reinforcing fiber, and then the low-temperature side Heating to below the radical generation temperature of the high temperature side curing agent above the radical generation temperature of the curing agent to form a semi-cured state, pressurizing the unsaturated polyester resin reinforced fiber in this semi-cured state and at the same time A method for producing a fiber-reinforced unsaturated polyester resin molded product, which comprises heating at a temperature higher than a radical generation temperature and finally curing.