JP3339250B2 - Prepreg material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg material. More particularly, the present invention relates to a fiber-reinforced prepreg having a low resin content and excellent winding workability.

[0002]

2. Description of the Related Art Fiber-reinforced prepregs have been widely used in sports and leisure applications as intermediate materials for molded articles such as golf shafts, fishing rods, badminton shafts and tennis racket frames. In recent years, fiber reinforced prepregs having a low resin content have been developed to further reduce the weight of golf shafts, fishing rods and the like.

[0003] In general, a fiber-reinforced prepreg is provided with a release sheet on one side thereof in the form of a sheet or a roll for shape retention, storage or transportation. When the fiber-reinforced prepreg is formed into a cylindrical body, usually, the release sheet is cut together, the fiber-reinforced prepreg is attached to a core, and the release sheet is peeled and wrapped to obtain a desired molded product. At this time, the fiber reinforced prepreg cut before being wound around the core body is left for about several hours, during which the resin reinforced prepreg having a low resin content is partially peeled from the release sheet, and irregularities are generated on the surface of the prepreg. (Hereinafter, irregularities on the surface of the prepreg are referred to as bumps). In a fiber-reinforced prepreg having a high resin content, since the amount of resin is large, the adhesion between the release sheet and the fiber-reinforced prepreg was good, and such a problem hardly occurred. Wrapping the fiber-reinforced prepreg having such irregularities around the core causes wrinkles and voids, which cause problems such as a decrease in strength and a poor quality of the obtained molded product.

In order to suppress unevenness of the prepreg surface, Japanese Patent Publication No. 60-37811 discloses a dimensional stability having an elongation of 0.5% or less with respect to a dimension in a completely dry state at a relative humidity of 60%. The invention using a good release sheet is disclosed.

However, in the case of fiber-reinforced prepregs having a low resin content, it has not been possible to sufficiently suppress unevenness of the prepreg surface even by using such a technique. In addition, in order to prevent the occurrence of bumps after cutting the prepreg, it is also conceivable to take measures such as shortening the leaving time after cutting, or increasing the environmental temperature for leaving, etc. It is difficult to increase the production efficiency of the product, and there is a problem that a large capital investment is required.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a fiber-reinforced prepreg having a low resin content and little generation of sloppy even after being cut and left. I do.

[0007]

The present invention has the following structure to solve the above problems. That is, pull in one direction
In a unidirectional prepreg material in which a prepreg composed of aligned reinforcing fibers and a matrix resin is adhered on a release sheet, the content of the matrix resin in the prepreg is 13 to 32% by weight. A unidirectional prepreg material having a peel resistance between the prepreg and the release sheet of 10 to 250 g / 25 mm.

Hereinafter, the present invention will be described in detail.

The prepreg material of the present invention is obtained by adhering a prepreg comprising a reinforcing fiber and a matrix resin on a release sheet.

As the reinforcing fibers used in the present invention, glass fibers, aramid fibers, carbon fibers, etc. can be exemplified, but when formed into molded articles, carbon fibers are particularly preferred since they exhibit particularly excellent mechanical properties. preferable. As the carbon fibers, polyacrylonitrile-based or pitch-based carbon fibers can be used.

As the matrix resin used in the present invention, an epoxy resin is usually used. Examples of the epoxy resin include bisphenol A type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, glycidylamine type epoxy resin, alicyclic epoxy resin, urethane modified epoxy resin, and brominated bisphenol A type epoxy resin. Can be used. These epoxy resins can be used alone or in combination of two or more, and furthermore, a liquid to a solid can be used. Usually, a curing agent is often used after being added to the epoxy resin.

The prepreg of the present invention has a resin content of 13 to 32% by weight, preferably 15 to 27% by weight, more preferably 17 to 25% by weight. If the resin content is less than 13% by weight, the prepreg of good quality and quality cannot be obtained because the amount of the resin is too small, and if it exceeds 32 % by weight, the unevenness of the surface of the prepreg can be reduced without applying the present invention. Rarely occurs.

In the present invention, the peel resistance between the prepreg and the release sheet is 10 to 250 g / 25 mm, preferably 3 to 250 g / 25 mm.
It needs to be 0 to 220 g / 25 mm. If the peel resistance is less than 10 g / 25 mm, the surface of the prepreg will be uneven. On the other hand, if it exceeds 250g / 25mm,
It becomes difficult to peel off the prepreg from the release sheet, and the workability deteriorates, for example, the release sheet is broken.

The peel resistance between the prepreg and the release sheet is as follows:
It can be measured as follows.

The prepreg material is cut into a strip having a width of 25 mm and a length of 270 mm to obtain a test piece. The prepreg side of the test piece is adhered to the surface of a stainless steel jig via a double-sided tape as shown in FIG. Fig. 2 shows the jig with the test piece attached.
Attached to the tensile tester as shown in
As a minute, the force required to peel the prepreg and the release sheet is measured. The measurement is performed at a measurement environment temperature of 23 ° C. and a humidity of 50%. The average value of the maximum load and the minimum load at the time of performing such a measurement is defined as the peel resistance.

The release sheet used in the present invention can have the peel resistance between the prepreg and the release sheet within the above range by appropriately adjusting the type and amount of the silicone release agent, for example. Preferably, the release degree of the release sheet is 110 to 400 g / 20 mm, preferably 150 to 340 g / 20 mm.
mm, more preferably a release sheet having a thickness of 180 to 300 g / 20 mm.

The degree of release of the release sheet is measured as follows.

A release sheet as a sample is fixed on a smooth glass plate, and a permanent adhesive acrylic emulsion type pressure-sensitive adhesive is applied using an applicator (125 μ / wet). Immediately after coating, bake and dry at 100 ° C. for 120 seconds. Immediately, another release sheet of the same kind is placed on the upper side, and is bonded to the surface of the adhesive using a rubber roller. After leaving it for about 30 minutes, it was cut into a 2 cm width test piece, and the upper release sheet was pressed at a pulling speed of 1 m / min.
The force at the time of peeling by 0 ° peel is measured, and the measured value is defined as the degree of release of the release sheet. The measurement length is 10 cm.

The release sheet used in the present invention has a dimensional change at room temperature of 0.6% or less (at a temperature of 20 ° C.,
Dimensional change when left in an environment of 65% humidity for 20 hours)
The use of such a material has an effect of further preventing the occurrence of unevenness.

Further, as the reinforcing fiber in the present invention,
In order to reduce the resin content of the prepreg, it is preferable to use one in which fiber bundles are aligned in one direction. In such a case, the ratio of the width to the thickness of the fiber bundle is 5 to 20.
0, preferably 8 to 150, more preferably 10 to 1
It is preferred to be in the range of 20. When the ratio is less than 5, the fiber bundle is hardly spread in the prepreg-forming step, the resulting prepreg may be cracked, or the matrix resin may be hardly impregnated into the fiber bundle. on the other hand,
Fiber bundles with a fiber bundle width to thickness ratio of more than 200 may be difficult to obtain in practice. Here, the width D (mm) of the fiber bundle is obtained by actual measurement, and the thickness t (mm) of the fiber bundle is a value obtained by the following equation.

T = (f × d) / (D / d) Here, f represents the number of filaments of the fiber bundle, and d (mm) represents the diameter of a single fiber.

[0022]

EXAMPLES The present invention will be described more specifically with reference to the following examples. In addition, the evaluation method of the prepreg in this example is as follows.

(1) Roughness of prepreg surface 1 m of prepreg material on which release sheet and prepreg are adhered
After cutting into a 1 m square and left for 1 hour, the number of convex portions having a major axis of 3 mm or more on the prepreg surface is counted. (2) Winding properties The prepreg material on which the release sheet and the prepreg are adhered is cut in the fiber direction to a width of 100 mm and a length of 300 mm, the release sheet is peeled from the prepreg material, and the prepreg has a diameter of 15 mm.
It is wound by hand around a cylindrical core of 500 mm in length. After winding, the prepreg is observed for wrinkles or projections.

Example 1 Epikote 828 and Epikote 1001 (bisphenol A glycidyl ether (epoxy equivalent: 189): Yuka Shell Epoxy Co., Ltd.)
100 parts by weight, 5 parts by weight of dicyandiamide and 3 parts by weight
5 parts by weight of (3,4-dichlorophenyl) -1,1-dimethylurea were uniformly mixed to obtain a one-part cured epoxy resin composition. This one-part cured epoxy resin composition was demolded by 2
A resin film is prepared by coating on release paper of 10 g / 20 mm. In a direction substantially parallel to the longitudinal direction of the resin film, the carbon fiber bundle having a ratio of the width to the thickness of the fiber bundle of 20 is uniformly aligned with a uniform tension, and then passed between hot rollers to be impregnated and simultaneously B-staged. A prepreg material was prepared in which a carbon fiber reinforced prepreg having a width of 600 mm and a resin content of 19% by weight was adhered to release paper. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 92 g /
It was 25 mm. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like.

Example 2 The prepreg had a resin content of 2
A prepreg material was prepared in the same manner as in Example 1 except that the amount was 2% by weight. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 127 g / 25 mm. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like.

(Example 3) A prepreg material was produced in the same manner as in Example 1 except that release paper having a release degree of 180 g / 20 mm was used. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 53 g / 25 mm. Table 1
The evaluation results are shown together with the ruggedness and winding property of the prepreg material.

Example 4 A prepreg material was prepared in the same manner as in Example 1 except that release paper having a degree of release of 250 g / 20 mm was used. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 206 g / 25 mm. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like.

(Example 5) The ratio of the width to the thickness of the fiber bundle is 96.
A prepreg material was produced in the same manner as in Example 1 except that the carbon fiber bundle was used. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 104 g / 25 mm.
Met. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like.

Example 6 A prepreg material was produced in the same manner as in Example 1 except that a carbon fiber bundle having a width to thickness ratio of 4 was used. In the obtained prepreg material,
The peel resistance between the prepreg and the release paper was 62 g / 25 mm. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like.

(Example 7) The ratio of the width to the thickness of the fiber bundle is 23.
A prepreg material was produced in the same manner as in Example 1 except that a carbon fiber bundle of 0 was used. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 74 g / 25.
mm. Table 1 shows the evaluation results together with the ruggedness, winding property and the like of the prepreg material.

Comparative Example 1 The resin content of the prepreg was 1
A prepreg material was prepared in the same manner as in Example 1 except that the amount was 2% by weight. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 8 g / 25 mm. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like. There was a lot of bumps and wrinkles occurred when wound around the core.

Comparative Example 2 A prepreg material was prepared in the same manner as in Example 1 except that release paper having a degree of release of 95 g / 20 mm was used. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 2 g / 25 mm. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like. There was a lot of bumps and wrinkles occurred when wound around the core.

Comparative Example 3 A prepreg material was prepared in the same manner as in Example 1 except that release paper having a release degree of 370 g / 20 mm was used. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 262 g / 25 mm. Table 1
The evaluation results are shown together with the ruggedness and winding property of the prepreg material. Although no squealing occurred, it was difficult to peel off the release paper from the carbon fiber reinforced prepreg when wound around the core body, and the winding took a very long time.

(Comparative Example 4) The resin content of the prepreg was 3
A prepreg material was produced in the same manner as in Example 1 except that the amount was 4% by weight. In the obtained prepreg material, the peel resistance between the prepreg and the release paper was 119 g / 25 mm. Table 1 shows the evaluation results together with the prepreg material's unevenness, winding property and the like. Although no bumps occurred, the amount of resin was too large, and the weight of the composite material member could not be reduced by using this prepreg.

[0035]

[Table 1]

[0036]

The prepreg material of the present invention has a peel resistance between the prepreg and the release sheet within the above range,
Despite the low resin content of the prepreg, the surface of the prepreg has little unevenness, thereby giving an effect of, for example, excellent workability when the prepreg is wound around a core.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a jig to which a prepreg material is attached, which is used when measuring a peel resistance between a prepreg and a release sheet in the present invention.

FIG. 2 is a schematic side view showing a state of a tensile test when measuring a peel resistance between a prepreg and a release sheet in the present invention.

[Explanation of symbols]

 1: double-sided adhesive tape 2: prepreg 3: release sheet 4: stainless steel plate 5: thread 6: clip 7: upper gripper of tensile tester 8: lower gripper of tensile tester

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-48343 (JP, A) JP-A-56-10532 (JP, A) JP-A-59-114046 (JP, A) JP-A-60-48 11315 (JP, A) JP-A-61-287936 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (5)

(57) [Claims] 1. A one- way prepreg material comprising a prepreg made of a reinforcing fiber and a matrix resin aligned in one direction adhered on a release sheet, wherein the content of the matrix resin in the prepreg is 13 to 32% by weight. %
The peel resistance between the prepreg and the release sheet is 10 to 250 g.
/ One-way prepreg material characterized by being 25 mm. 2. Reinforcing fibers and matrices aligned in one direction
Prepreg made of resin is stuck on release sheet
In a single unidirectional prepreg material
The matrix resin content in the
Yes, peel resistance between prepreg and release sheet is 10 to 2
50 g / 25 mm unidirectional prep
Leg material. 3. The matrix resin comprises an epoxy resin.
The one-way pre-charge according to claim 1 or 2, wherein
Preg material . 4. The degree of release of the release sheet on the prepreg sticking side is
110-400g / 20mm
The unidirectional prepreg material according to any one of claims 1 to 3. 5. The unidirectional prepreg according to claim 1, wherein the ratio of the width to the thickness of the fiber bundle is in the range of 5 to 200.