JPS6234775B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a resin composition that can adjust the tack of prepreg without reducing the physical properties of the composite material and can prevent the occurrence of cracks during storage of unidirectional prepreg, and this resin composition. The present invention relates to a carbon fiber prepreg impregnated with carbon fiber prepreg and a method for manufacturing the same.

Carbon fiber is known to be excellent as a reinforcing material for composite materials with synthetic resins, and one molding method is to form a so-called prepreg impregnated with uncured resin and then mold and harden it into a product.

This carbon fiber prepreg has mainly been made of epoxy resin from the viewpoint of the preservability of the prepreg due to its adhesive strength with carbon fibers and the stability of the matrix.

In addition, the present inventors have previously discovered the effectiveness of carbon fiber prepregs having an unsaturated polyester resin matrix, which are fast-curing and capable of being hybridized with glass fiber composite materials having an unsaturated polyester resin matrix. We have developed a method for producing carbon fiber prepreg using a resin matrix using the hot melt method. That is, an unsaturated polyester prepolymer whose constituent units are 20 to 60 moles of isophthalic acid, 80 to 40 moles of fumaric acid, and 100 moles of propylene glycol, and 10 to 10 moles of diallylphthalate or diacetone acrylamide.
A carbon fiber prepreg having excellent composite material properties is produced by a hot melt method using a resin composition consisting of 50% by weight and a curing catalyst.

On the other hand, as for the quality required for prepreg, it goes without saying that the physical properties of the composite material are excellent, but one of the important qualities is tack from the viewpoint of workability and handling. When using the same unsaturated polyester prepolymer, the tack must be adjusted by adjusting the amount of crosslinking monomer.

However, in this case, if the physical properties of the composite material are sacrificed or the tack of the prepreg is weakened by changing the amount of crosslinking monomer, the amount of diallyl phthalate monomer will be reduced, which will inevitably increase the melt viscosity and cause the hot melt to deteriorate. Prepreg production by this method has drawbacks such as difficulty in kneading the resin and impregnating carbon fibers with the resin.

Therefore, if there were a means to weaken the tack without increasing the melt viscosity of the resin mixture and without deteriorating the physical properties of the composite material, it would be extremely effective for carbon fiber prepregs using unsaturated polyester resin as a matrix by hot melting. be. Furthermore, unidirectional sheet-like carbon fiber prepregs using unsaturated polyester resin as a matrix are more likely to crack during storage than epoxy resin prepregs, which often poses quality problems.

As a result of intensive studies, the present inventors found that by adding a prepolymer of diallyl phthalate, it was possible to weaken the tack without reducing the physical properties of the composite material, and it was possible to manufacture the composite material by the hot melt method. The inventors have discovered that the occurrence of cracks in stored products is significantly reduced in the case of unidirectional prepreg, and have arrived at the present invention.

That is, isophthalic acid 20 to 60 as the dibasic acid component.
100 parts by weight of a solid unsaturated polyester prepolymer consisting of 80 to 40 moles of fumaric acid as ethylenically unsaturated dibasic acid and 100 moles of propylene glycol as the glycol component and 15 to 30 parts by weight of diallyl phthalate, 3 to 15 By using parts by weight of diallyl phthalate prepolymer, the tack of the prepreg is weakened without interfering with the prepreg manufacturing process by the hot melt method or deteriorating the physical properties of the composite material, and the occurrence of cracks during storage of the unidirectional prepreg can be prevented. I found out that it is possible.

If we try to weaken the toughness of the prepreg by reducing the amount of diallyl phthalate monomer added, the deterioration of physical properties and troubles in producing prepreg using the hot melt method will be unavoidable, as described above, but by adding diallyl phthalate prepolymer, The tack of the prepreg can be weakened without deteriorating the physical properties of the material and without causing any problems in producing the prepreg by the hot melt method. The diallyl phthalate prepolymer used here is a relatively linear polymer having polymerizable double bonds in the molecule obtained by initial polymerization of diallyl phthalate monomers, and is thermoplastic. For the purposes of this invention, the softening point is between 15 and 70.
℃, especially preferably 20 to 60℃. Softening point is 15
The effect of weakening the tack is small below 70℃.
The above materials are not preferred because the melt viscosity of the resin increases, making it difficult to knead the resin and impregnate carbon fibers with the resin during the prepreg manufacturing process.

If the amount of diallyl phthalate monomer is less than 15 parts by weight per 100 parts by weight of the unsaturated polyester resin prepolymer used in the present invention, the melt viscosity of the resin will be high, not only making it difficult to produce prepreg by the hot melt method, but also decreasing the physical properties of the composite material. Undesirable. Moreover, if it exceeds 30 parts by weight, the tack of the prepreg will be too strong and it will no longer be possible to weaken it to the desired tack even by adding diallyl phthalate prepolymer.

The amount of diallyl phthalate prepolymer added is 3
~15 parts by weight is suitable. If it is less than 3 parts by weight, the effect of weakening the tack and preventing the occurrence of cracks in the prepreg is small, and if it is more than 15 parts by weight, not only the tack of the prepreg becomes too weak, but also it becomes difficult to impregnate carbon fiber with resin in hot melt prepreg production.

Coupled with the fact that even if diallyl phthalate prepolymer is added within the scope of the present invention, the adhesion strength of the unsaturated polyester resin matrix of the present invention to carbon fibers does not change at all, and the interlaminar shear strength (ILSS) shows 9 kg/mm ² or more. The resin composition of the invention is of great significance as it significantly improves the quality and commercial value of carbon fiber prepregs using unsaturated polyester resin as a matrix.

Next, a method for manufacturing the prepreg of the present invention will be explained.

A predetermined amount of unsaturated polyester prepolymer, diallyl phthalate, and diallyl phthalate prepolymer are melt-kneaded in a kneader at a temperature of 70 to 110°C. The resin mixture is kneaded with a predetermined amount of curing catalyst using a three-roll mill, and then coated onto a release paper in the form of a film using a film coater. Carbon fiber aggregates are placed on the release paper coated with this resin, and the release paper is further introduced on top of the release paper.
After passing through a heating plate heated to 140°C, the carbon fibers are pressed with a linear pressure of 0.1 to 100 kg/cm using a hot roller heated to 60 to 160°C to spread them out and form them into a sheet. Impregnate with resin. The carbon fiber aggregate can be used in any form such as unidirectional or random web.

The curing catalyst is preferably one that is stable at a constant temperature and has a high decomposition rate at high temperatures, such as t-butyl peroxybenzoate.

This will be explained below using examples.

Example 1 100 parts by weight of a solid unsaturated polyester prepolymer (Polymer X381 manufactured by Takeda Pharmaceutical Co., Ltd.) consisting of 40 moles of isophthalic acid, 60 moles of fumaric acid, and 100 moles of propylene glycol, 23 parts by weight of diallyl phthalate monomer, and 8 parts by weight Diaryl phthalate prepolymer (Daiso Tap L manufactured by Osaka Soda, softening point 40°C) was homogenized by kneading at 90°C in a kneader, and then transferred to a roll mill to make a t-
The mixture was kneaded with 6 parts by weight of butyl peroxybenzoate. The resin composition was coated on a release paper using a film coater, carbon fibers (Beshuite 7-6K manufactured by Toho Veslon) were introduced in one direction and at equal intervals, and a release paper was further introduced on top of this.
Pass it over a heating plate heated to 120°C for 30 seconds. Furthermore, 30Kg/cm is placed on a hot roller heated to 130℃.
A unidirectional sheet-like prepreg was manufactured by pressing the carbon fibers with a linear pressure of 100 mL to form a sheet, and at the same time impregnating the carbon fibers with a resin.

This prepreg had such a weak tack that it could be easily peeled off even when attached to each other at 25°C, and almost no cracking occurred even when left at room temperature for several days. In addition, this prepreg is laminated in one direction and heated to 150°C.
The physical properties of the molded product molded under curing conditions of 7 kg/cm ² for 30 minutes were as follows.

Bending strength 162Kg/mm ² Flexural modulus 12.9T ^/ mm Interlaminar shear strength (ILSS) 9.2Kg/mm ² Fiber volume content (V) 60% Comparative example 1 Isophthalic acid 40 mol, fumaric acid 60 mol, propylene glycol 100 Example 1 was repeated using 100 parts by weight of a solid unsaturated polyester prepolymer (Polymer X381, manufactured by Takeda Pharmaceutical Co., Ltd.), 18 parts by weight of diallyl phthalate monomer and 6 parts by weight of t-butyl peroxybenzoate. Although a unidirectional carbon fiber prepreg was produced, the melt viscosity of the resin composition was higher than in Example 1, making it difficult to knead the resin and impregnate the carbon fibers with the resin. Moreover, the tack of the obtained prepreg is as shown in Example 1.
However, many cracks appeared when left at room temperature for one day. This prepreg was laminated in one direction and molded under the same conditions as in Example 1. The properties of the molded product were as follows.

Bending strength 159Kg/mm ² Bending modulus 13.0T/mm ² ILSS 8.3Kg/mm ² V 60% Compared to Example 1, ILSS is lower.

Claims (1)

[Claims] 1. 20 to 60 mol of isophthalic acid, 80 to 60 mol of fumaric acid
A resin composition comprising 100 parts by weight of a solid unsaturated polyester prepolymer consisting of 40 moles of polypropylene glycol and 100 moles of propylene glycol, 15 to 30 parts by weight of diallyl phthalate, 3 to 15 parts by weight of diallyl phthalate prepolymer, and a curing catalyst. 2 Isophthalic acid 20~60mol, fumaric acid 80~
Impregnated with a resin composition consisting of 100 parts by weight of a solid unsaturated polyester prepolymer consisting of 40 moles and 100 moles of propylene glycol, 15 to 30 parts by weight of diallyl phthalate, 3 to 15 parts by weight of diallyl phthalate prepolymer, and a curing catalyst. Carbon fiber prepreg. 3 Isophthalic acid 20~60mol, fumaric acid 80~
A resin composition consisting of 100 parts by weight of a solid unsaturated polyester prepolymer consisting of 40 moles and 100 moles of propylene glycol, 15 to 30 parts by weight of diallyl phthalate, 3 to 15 parts by weight of diallyl phthalate prepolymer, and a curing catalyst is separated. It is characterized in that it is spread on a paper pattern to form a film, a carbon fiber aggregate is placed on top of this, and the resin composition is impregnated into the carbon fiber aggregate by heat-pressing at 60 to 160°C. A method for producing carbon fiber prepreg using unsaturated polyester as a matrix.