JPH01148545A - Interlaminar hybrid laminated material - Google Patents

Abstract

PURPOSE:To obtain a laminated body whose compression strength has been improved, by a method wherein a ratio of the tensile modulus of an inorganic fiber constituted of each element of Si, Ti or Zr and O to that of a carbon fiber is decided to fall within a range of a specific value. CONSTITUTION:An inorganic fiber constituted of a carbon fiber and each ele ment of Si, Ti or Zr, C and O is selected and prepared so that a ratio of the tensile modulus of the inorganic fiber to that of the carbon fiber falls within a range of 0.6-1.4. An epoxy resin is infiltrated into the carbon fiber which is wound up round a drum winder, heated and carbon fiber prepreg which is in a semi-cured state and arranged unidirectionally is prepared. The inorganic fiber prepreg which is in a semi-cured state and arranged unidirectionally is prepared similarly by making use of the inorganic fiber comprised of the Si, Ti or the Zr, C and O. Two kinds of the prepreg are superposed upon each other in a unidirectional direction under necessary constitution by making use of the two kinds of the prepreg and press lamination of them is performed at 100-250 deg.C, through which a laminated material whose interlaminar separation is rare and compression strength has been improved is obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a prepreg having particularly excellent compressive strength, which is manufactured by laminating prepregs in which carbon fibers and specific inorganic fibers are each impregnated with a thermosetting resin. Regarding the eyebrow hybrid laminated material ↓.

(Prior art and its problems) Carbon fiber-reinforced plastic composites have high specific strength and specific modulus, and are therefore used in sports and leisure goods. However, this material has technical problems such as low compressive strength or bending strength, low elongation and brittleness.

Therefore, attempts have been made to solve the above-mentioned problems by using a so-called hybrid laminate material that combines a carbon fiber layer and other fiber layers. Conventionally, glass fibers and aramid fibers have been preferably used as fibers to be combined with carbon fibers. However, glass fiber has the problem of low strength and elastic modulus, and is also heavy.
Aramid fibers have a problem of high elongation but low compressive strength and easy moisture absorption. Therefore, it is difficult to say that a plastics composite material obtained by using a combination of these fibers and carbon fibers is a material that is practically satisfactory.

JP-A-62-7737 discloses that Si, Ti or Zr
, a composite material obtained by laminating prepregs impregnated with plastics on inorganic fibers and carbon fibers each composed of the elements C and 0, and pressurizing and heating this laminate,
So-called interlayer hybrid composites have been disclosed. This composite material takes advantage of the excellent features of the above-mentioned inorganic fibers, namely good adhesion with the matrix resin and flexibility of the fibers themselves, and has a higher tensile strength than carbon fiber reinforced plastic composite materials. Excellent in interlaminar shear strength and Charpy impact strength.

In recent years, inorganic fiber-reinforced plastic composite materials are required to have high bending strength and compressive strength in addition to the above-mentioned excellent strength. From this point of view, the composite material described in the above publication has room for improvement in bending strength, as shown in the Examples of the publication.

(Objective of the Invention) The object of the present invention is to provide a laminate material that maintains the advantages of the glabellar hybrid laminate material described in JP-A-62-7737, while improving its compressive strength, which is its biggest problem. It's about doing.

(Technical Means for Solving the Problems) The above object of the present invention is to impregnate each of carbon fibers and inorganic fibers substantially composed of 5iXTi or each element of Zr, C and 0 with a thermosetting resin. In the interlayer hybrid laminate manufactured by laminating prepregs, the ratio of the tensile modulus of the inorganic fiber to the tensile modulus of the carbon fiber is 0.6.
This is achieved by a glabella hybrid laminate characterized in that it is within the range of ~1.4.

The carbon fiber in the present invention may be one using any of polyacrylonitrile, petroleum pitch, and coal pitch as its precursor. Further, it may be either carbonaceous fiber or graphite fiber, which are called depending on the firing temperature.

The tensile modulus of carbon fiber varies depending on the type of precursor, firing temperature, etc., but generally carbon fiber has a tensile modulus of 15 to 15.
30t/nun2, 30-50t/nun2 for graphite fibers
This is body 2.

The inorganic fiber in the present invention is US Patent No. 434271.
It can be prepared according to the method described in Specification No. 2 and Specification No. 4515742, the descriptions of which are incorporated herein by reference.

An example of the preparation method is shown below.

A polycarbosilane having a number average molecular weight of 200 to 10,000 and having a main chain skeleton represented by the formula R 1+5i-CH2+ (wherein R represents a hydrogen atom, a lower alkyl group, or a phenyl group), and a formula MX4 (However, M in the formula represents Ti or Zr, and X has 1 carbon number.
~20 alkoxy groups, phenoxy groups, or acetylacetoxy groups) of the polycarbosilane (total number of structural units of Si-CHz+ vs. At least one of the silicon atoms of the polycarbosilane is added at a quantitative ratio such that the ratio of the total number of structural units is within the range of 2=1 to 200:1, and heated and reacted in an atmosphere inert to the reaction. a first step in which a spinning stock solution of the above-mentioned copolymer is prepared; A manufacturing method consisting of a second step of spinning, a third step of making the spun fibers infusible, and a fourth step of firing the infusible spun fibers in a vacuum or in an inert gas atmosphere at a temperature range of 800 to 1500°C. In this way, the inorganic fibers of the present invention can be obtained.

The proportions of each constituent element in the inorganic fiber are: Si: 30 to 60% by weight, Ti or Zr: 0.5 to 35% by weight, preferably 1 to 1% by weight.
0% by weight, C: 25-40% by weight, and 0: 0.01-30% by weight.

Generally, the tensile modulus of the above inorganic fibers is 20 to 25 t/mm.
It is within the range of 2.

What is important in the present invention is the relative value of the tensile modulus of carbon fiber and inorganic fiber.

That is, the ratio of the tensile modulus of the inorganic fiber to the tensile modulus of the carbon fiber used is 0.6 to 1.4, preferably 0.6 to 1.4.
Must be within the range of 8 to 1.2. If the ratio of the elastic modulus of both is out of the above range, delamination between the carbon fiber layer and the inorganic fiber layer will occur in the interlayer hybrid laminate made using these fibers due to the difference in tensile modulus. As a result, the compressive strength of the laminate becomes low. Therefore, in the present invention, it is necessary to select inorganic fibers and carbon fibers so that the ratio of tensile modulus falls within the above range.

The ratio of inorganic fibers to the total of inorganic fibers and carbon fibers is preferably 1 to 80% by volume, particularly 3 to 70% by volume. If the above proportion is less than 1% by volume, the effect of improving the compressive strength of the laminated material is small, and if it is greater than 80% by volume, the proportion of carbon fiber decreases relatively, and the high tensile strength and lightweight properties of carbon fiber are added to the laminated material. It becomes difficult to grant.

The total proportion of carbon fibers and inorganic fibers in the laminate is usually 30 to 0% by volume, preferably 45 to 65% by volume.

Although carbon fibers and inorganic fibers are preferably used in the form of unidirectionally aligned fibers, they can also be used in the form of a woven fabric (fabric) formed by weaving the respective fibers.

Further, both fibers may be subjected to known surface treatment and sizing treatment.

The thermosetting resin in the present invention is not particularly limited, and examples include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenol resins, bismaleimide resins, and polyimide resins. Among these resins, epoxy resins are preferably used. The above epoxy resin is
It is a resin composition consisting of polyepoxide, a curing agent, a curing catalyst, etc.

Examples of polyepoxide include bisphenol A,
Examples include glycidyl compounds of F and S, glycidyl compounds of cresol novolak or phenol novolak, and alicyclic polyepoxides.

Other examples of polyepoxides include glycidyl compounds of polyhydric phenols, polyhydric alcohols or aromatic amines.

Among these polyepoxides, the glycidyl ether of bisphenol A, the glycidyl compound of talesol novolak or phenol novolak, the glycidyl compound of diaminodiphenylmethane, and the glycidyl compound of aminophenol are generally used. In addition, when the laminate material of the present invention is used as a member requiring high functionality such as a primary structural material of an aircraft, among the above polyepoxides,
Preference is given to using glycidyl compounds of polyfunctional amines such as diaminodiphenylmethane.

The laminate of the present invention is manufactured by laminating prepregs in which carbon fibers and inorganic fibers are each impregnated with a thermosetting resin, and then curing the thermosetting resin.

Methods for preparing prepreg include a method in which a large number of filament threads made of the above-mentioned fibers are aligned in one direction and sandwiched between thermosetting resins to make a prepreg, and a bundle of filament threads impregnated with thermosetting resin is wound around a drum. A method of preparing prepreg by pulling a large number of filament threads together and then melting and impregnating them with a thermosetting resin film. A method of introducing a woven or nonwoven fabric into a thermosetting resin reservoir, impregnating it, and drying it. Methods known per se can be appropriately employed, such as a method of preparing a prepreg by melting and impregnating a sheet-like material made of a thermosetting resin into a woven or nonwoven fabric.

There are no particular restrictions on the method of laminating prepreg.
All known methods such as hand layup method and automatic layup method can be employed.

The lamination form may be any of the commonly practiced symmetrical lamination, asymmetrical lamination, reverse symmetrical lamination, etc. Further, there is no particular restriction on the lamination order, and any repeating thickness can be used.

The method of forming a laminate from a prepreg laminate is not limited in any way, and may include known methods such as vacuum bag/autoclave curing method, hot press molding method, sheet winding method, sheet wrapping method, tape winding method, tape wrapping method, etc. The following methods can be adopted as appropriate.

Curing conditions such as curing temperature, curing pressure, and curing time are determined by the thermosetting resin used.

For example, when using an epoxy resin as the thermosetting resin, the general curing temperature is 100 to 250'C.

Preferably it is 120-200°C. Moreover, pre-cure or post-cure can be performed as appropriate.

The glabellar hybrid laminate material of the present invention can be easily produced with good reproducibility into products with three-dimensional shapes of various sizes having curved surfaces or irregularities, in addition to products with simple shapes such as plates and pipes.

(Example) Examples and comparative examples are shown below. The physical properties of the glabellar hybrid laminate on each side were measured using Tensilon UTM5T manufactured by Orientic ■ at a temperature of 23°C for the following test pieces.
1 each along the length of the fiber under conditions of 50% relative humidity at °C1.
Measured 0 times. The bending test is a three-point bending test at span/width=32.

-5 Vertical: Torso Test speed ■Tension test 12.7 200 1.5 2 mm
7 minute compression test 10 60 2 0.5mm
/min bending test 12.7 85 2 2mm/
The fiber volume content (Vf) of the fractionally laminated material is ASTM D317
Measured according to 1. Its unit is volume %.

In the following, all parts are by weight.

Example 1 Bisphenol A epoxy resin (manufactured by Ciba Geigy,
After uniformly mixing 100 parts of XB2879A) and 20 parts of a dicyandiamide curing agent (manufactured by Ciba Geigy, XB2879B), the mixture was dissolved in a mixed solvent of methyl cellosolve and acetone at a weight ratio of 1:1 to obtain 28 parts of the above mixture. A % weight solution was prepared.

Carbon fiber (manufactured by Toho Rayon ■, Besphite HTA60
00: Tensile modulus 24t/+nm2, specific gravity 1°77
) was impregnated with the above solution, then wound in one direction using a drum winder and heated in a hot air circulation oven at 100°C for 14 minutes to prepare a semi-cured unidirectionally aligned carbon fiber prepreg. This prepreg had a resin content of 38% by weight and a thickness of 0.2 mm.

Inorganic fiber consisting of Si, Ti, C and 0 (manufactured by Ube Industries, Tyranno fiber: tensile modulus 21 t/mm", specific gravity 2
．． A unidirectionally aligned tyranno fiber prepreg in a semi-cured state was prepared using 35) in the same manner as above. The resin content of this prepreg is 30% by weight, and the thickness is 0.2 mm.
Met.

Using the above two types of prepregs, overlap them in one direction with the configuration shown in Table 1, and
By press forming for 250mm x 250mm
A unidirectional interlayer hybrid laminate with a size of mm was produced. Various test pieces were cut out from this laminated material using a diamond saw and subjected to tests. The results are shown in Table 2.

Example 2 Example 1 except that the laminated structure was changed as shown in Table 1.
The same method was repeated. The results are shown in Table 2.

Example 3 The same method as Example 2 was repeated except that the thickness of the tyranno fiber prepreg was changed to 0.15 nnn. Second result
Shown in the table.

Example 4 The same method as Example 2 was repeated except that the thickness of the tyranno fiber prepreg was changed to 0.1 mm. The results are shown in Table 2.

Comparative Example 1 As carbon fiber, carbon fiber with tensile modulus of elasticity 42t 7mm2 and specific gravity 1.83 (manufactured by Toho Rayon ■, Besphi)
The same method as in Example 1 was repeated except that HM40) was used. The results are shown in Table 2.

Comparative Example 2 The same method as in Example 2 was repeated except that the carbon fiber used in Comparative Example 1 was used as the carbon fiber.

The results are shown in Table 2.

Comparative Example 3 Example 1 except that tyranno fiber prepreg was not used
The same method was repeated. The results are shown in Table 2.

Table 1 Tensile Elasticity T Ratio Composition Ratio "Left Bond X Month Example 1 0.9 31 TCTCCCC
TCTN 2 0.9 13' TCC
CCCCCCT〃3 0.9 10 TC
CCCCCCCT" 4 0.9 6
TCCCCCCCCCT Comparative Example 1 0.5 3
1 TCTCCCCT〃2 0.5
13 TCCCCCCCCCT // 3 -
OCCCCCCCCCCC In the structure column of Table 1, T indicates a tyranno fiber layer, and C indicates a carbon fiber layer.

Claims (1)

[Claims] In the interlayer hybrid laminate material manufactured by laminating prepregs in which carbon fibers and inorganic fibers substantially composed of Si, Ti, or each element of Zr, C, and O are impregnated with a thermosetting resin, the above-mentioned The ratio of the tensile modulus of the inorganic fiber to the tensile modulus of the carbon fiber is 0.6 to 1.
An interlayer hybrid laminate material characterized by being within the range of 4.