JPS5948155A - Both-surface exfoliating sheet and prepreg material containing said sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a double-sided release sheet that is particularly excellent in moisture-resistant dimensional stability and heat-resistant dimensional stability, and a prepreg of catching fibers supported on one side of such a release sheet. Regarding prepreg materials.

Release sheets are widely used in the manufacture of carbon fiber and other reinforcing fiber prepreg materials. For example, in the production of a unidirectional carbon fiber prepreg material, carbon fibers arranged parallel to each other in one direction in a sheet shape are impregnated with a thermosetting resin, a release sheet is attached to this, and the resin is applied. Preparation. When producing a fiber-reinforced resin material, a release sheet-attached prepreg, that is, a prepreg material, is cut into an arbitrary shape, the required number of sheets are laminated in a predetermined direction excluding the release sheet, and the resin is cured by heating.

The release sheet used in making one of such prepreg materials is generally required to have the following properties. (
a) It should have removability on both sides and exhibit appropriate temporary adhesion to the prepreg. (h) To withstand the heat encountered in the manufacturing process of prepreg materials (e.g., 100 to 17
Can withstand 0C heat. ). (C> low heat shrinkage rate,
Good heat resistance and dimensional stability. (d) Good moisture resistance and dimensional stability.

Conventionally, there is no known sheet that satisfies the above-mentioned requirements among the pane sheets used in the manufacturing process of open fiber prepreg materials for reinforcement. For example, a release sheet that has been widely used in the past is made of kraft paper, a coating layer of anchor material formed on both +nr of this kraft paper, and a coating layer of @release formed on the surface of each coating layer. Something is known. This spit release sheet is mainly composed of kraft paper that is easily wetted by 1 vol and has a low elastic modulus, so the elongation of the sheet at 90 degrees due to moisture absorption and the frequent use of release sheets in the manufacturing process of prepreg materials, Afterwards, the tension is released and the contraction is large, causing the reinforcing fibers to lift up from the surface of the release sheet (
(sagging) or meandering (sagging) within the surface of the release sheet, resulting in disordered alignment.

Further, if the prepreg material is a prepreg material bonded with scrim cloth, the scrim cloth will rise and separate from the reinforcing fibers. Therefore,
When the prepreg is peeled off from the release sheet during use, the prepreg becomes like a corrugated sheet, which makes it difficult to handle, and it is not possible to obtain an m# strong reinforced resin material with high physical properties.

JP-A-5/+-10532 proposes a unidirectional prepreg material using a paper release sheet that has an elongation of 0.5% or less with respect to its bone-dry dimensions under 60% relative humidity. has been done. However, the inventors have found that even if paper with good moisture-resistant dimensional stability is used, curling and channeling cannot be avoided during production, and paper that has both moisture-resistant dimensional stability and heat-resistant dimensional stability is particularly important. Satisfactory results cannot be obtained without a release sheet.

The object of the present invention is to provide a release sheet that satisfies the above-mentioned requirements and, in particular, has both moisture-resistant dimensional stability and heat-resistant dimensional stability, as well as a release sheet that supports a reinforcing fiber prepreg on such a release sheet. Our goal is to provide prepreg materials that can

Therefore, in one aspect, the present invention includes a paper base material, a coating layer of a peeling agent formed on one surface of the paper base material, an aluminum foil laminated to the other surface of the paper base material, and a coating layer of a peeling agent formed on one surface of the paper base material; Provided is a double-sided release sheet characterized by having a coating layer of a release agent formed on the surface.

In another aspect, the present invention provides a prepreg material comprising a reinforcing fiber prepreg supported on one side of a release sheet as described above.

Attached is a sectional view showing a typical example of the double-sided release sheet of the present invention. As shown in the figure, a release agent coating layer 5' is formed on one side of the paper base material 1 via an undercoat layer 4', and an adhesive layer 3' is formed on the opposite side of the paper base material 1. An aluminum foil (hereinafter referred to as "At foil") 2 is pasted together via the . Furthermore, on the surface of the At foil, a coating layer 5 or 119 of an AF agent is peeled off via an undercoat layer 4.
It has been widened.

As the paper base material used in the present invention, one that can withstand the heat (generally 100 to 170p) encountered during the helical forming process of the prepreg material and does not undergo large dimensional changes upon absorption of moisture is used.

Generally, high-quality paper, kraft paper, glassine paper, roll paper, etc. with a basis weight of about 5o to 1501/- are used. especially,
Single-glazed bleached kraft paper with a thickness of about O, OS ~ 0.21 is preferable because it has low elongation upon moisture absorption. Both surfaces of the paper base are coated with starch,
They are sealed with a tree-friendly polymer material such as polyvinyl alcohol or an anchor material such as polyethylene.

That is, it is preferable to have a coating layer of the anchor material.

The thickness of At foil is 50μ or less, generally 3 to 50μ,
Preferably, one with a diameter of 5 to 20 μm is used.

If the At foil is too thick, the prepreg material will undergo plastic deformation. The At foil is attached to one side of the paper using a heat-resistant adhesive such as acrylic resin.

This adhesion can be carried out in a conventional manner by using an adhesive of 1 to 20 S'/ltt' (in terms of solid content) and pressing with a roll coater or the like, followed by drying and curing.

On both surfaces of the At foil paper base material laminate, a @removal coating layer is formed via a JLlf undercoat layer.

As the undercoat layer, a hydrophilic polymeric substance such as polyvinyl alcohol having good heat resistance and peelability may be used in the form of an emulsion or a solution. The application rate is 1-2
0 f/lr? (solid content conversion vI).

As release agents, conventional non-silicone resins such as silicone/based resins or long chain alkyl acrylate polymer resins are used. Preferred stripping! -'A [agent is a condensation reaction type or addition reaction type silicone resin of polydimethylsiloxane and polydimethylhydrodiene siloxane. Application of release agent: 0.3~2y/)1? (based on solid content), and coating can be carried out according to commonly used methods.

A/ of the '+dJ M sheet produced as described above, 1 m on the opposite side from the foil forming surface, the tab υ coating layer 5'
WIIM ill+ prepreg for supplementary 1jl is temporarily attached and supported on top of it.

The reinforcing fibers include carbon fibers, glass fibers, and organic high-elastic fibers (for example, polyaramid fibers such as "KEVLAR" manufactured by DuPont in the United States), and one of these may be used. Two or more types may be used in combination.

Prepreg is made by pulling strands of reinforcing fibers each having a number of single threads in the order of several thousand in one direction, or by aligning them in one direction so that the fiber axes intersect with each other at any angle between 0 and 90 degrees. B-stage epoxy resins, unsaturated polyester resins, phenolic resins, and polyimides can be used in multi-layer laminations, cross-layers, or unidirectional and cross-layer laminates. It is impregnated with thermosetting resin such as resin. A scrim cloth made of carbon fiber, glass fiber, organic hexaelastic fiber, etc. may be bonded to the surface thereof, that is, the surface opposite to the surface supported by the peeling sheet.

Two or more types of reinforcing fibers 01, for example, carbon fibers, glass fibers, organic high modulus fibers, etc., are alternately arranged in several rows with regularity and pulled in one direction, or carbon fibers are pulled in one direction. Cross-laminate fiberglass fibers or organic high-modulus fibers aligned in one direction, or mix carbon fibers with glass fibers or organic high-modulus fibers, or create woven cloth. Used in combination.

The thickness of the prepreg is 0.02 to 1.0 mm, preferably 0.03 to 0.5 mm, and the reinforcing fiber content is 50 to 85%, preferably 40 to 60%.
Weight%.

When using scrim cloth, if it is made of glass (substitute fiber), the thickness should be 0.01 to 0.1, preferably 0.02 to 0.02 o, osw, and weight per unit area of 1.0 to 30.
fl/m', preferably 15-40 ff/? 11
', and when it is made of carbon fiber or organic high elastic fiber, the thickness is 0.02 to 0.15 mm, preferably 0.1 mm.
03~0,1 dragon, weight 10~90f! -/) 11 Preferably 20-60W/n? It is.

Since the 'Nl ii+1 sheet of the present invention has aluminum foil bonded to the side opposite to the prepreg supporting surface, the aluminum foil prevents the paper base material from absorbing moisture, and also slows down the rate of moisture absorption. Therefore, stretching due to moisture absorption can be prevented. Also,
Shrinkage due to dehumidification and thermal shrinkage are also very small. Additionally, aluminum foil has a higher modulus of elasticity than kraft paper and the like, and can withstand stress during the manufacturing process of prepreg materials. Therefore, it is possible to prevent sagging, sagging, or lifting of the scrim cloth, and it is possible to obtain an easy-to-handle scale or a fiber-reinforced resin material with high physical properties.

Hereinafter, the present invention will be described and explained in more detail with reference to Examples.

Example paper The base material was single gloss bleached kraft paper (1318051'/
n? , thickness 85μ) high quality paper (basis weight 80p/7, thickness 85μ)
μ) and unbleached kraft paper (Tsuboit B OS'/n
? , thickness 85μ) were used, respectively. It was. Acrylic adhesive (Cypinol Re-902)
, Seiden Kagakusha + (, Il), and applied the adhesive with a roll coater to At/lr? (Solid content) Coated At foil (
(thickness: 7 μm) was laminated on one side of each paper base material and dried. Next, polyvinyl alcohol (Denka Poval 17E, air,
(manufactured by Ki Kagaku Kogyo Co., Ltd.) was applied in an amount of 21/- and dried. Then apply a silicone release agent for light release (8RX-357, manufactured by Toray Silicone Co., Ltd.) on the foil surface, and a silicone release agent for heavy printing (SRX-[70:)-manufactured by Toray Silicone Co., Ltd.] on the paper surface. Each ISF/i (solid content) was coated with a roll coater and dried and cured (Sample AI, 2
゜3). As a comparative sample, a sample treated in the same manner as above except that no aluminum foil was laminated was produced (sample A4, 5.6).

The heat resistance and moisture resistance dimensional stability of the release sheet obtained by the above treatment were measured and are shown in Table 1.
:e? ! “7. Yo-F7.

Table 1 * After heating the sample to 150C, cool it to 20 [4' AI].
Measure the shrinkage rate (%).

*Chapter (A) J, TAPPI gauze pulp trial method B2B-
According to 18, temperature 20C1 humidity 33%RH~85
Measured at %RH.

Medium *Chapter (b) RH60% f, f according to the method specified in JP-A No. 56-10532, using the π1 method in an absolutely dry state.
The dimensions of the top are shown as %(stretched).
.

The numbers in parentheses are RH 60% and moisture content %.

****C) indicates the elongation of the base material (%) East 1↑5 (The company's carbon fiber "Trega T-300 (average Φ thread diameter 71t, number of single lines 6,000) is q in one direction. 5A oily shell flavor
, 4-layer epoxy grease-resistant "Epicoat °'1004,"
Boron fluoride and monoethylamine are 10 j 1
1i'# dissolved in methyl ethyl ketone in a 0:1 ml ratio
Then, the resin was impregnated with 1f of resin containing 601% resin, and then the resin was placed on two types of release sheets, and 150C
After evaporating the methyl ethyl ketone by passing it through an air-drying oven, the carbon fiber assembly was pressed between a pair of hot rolls with a surface rrII wet IW of 110C to press and spread the carbon fiber assembly to produce a prepreg material. In this prepreg material, the thickness of the prepreg excluding the release sheet is *4J O,12+1!1.
1, carbon rip, 41p (7) M content is about 6
Furthermore, the two types of release sheets of the prepreg are one-sided bleached kraft paper/At (sample A1) and one-sided bleached kraft paper (sample A4) in the P1λ1 table. ), and the one using single gloss bleached kraft paper/At has prepreg supported on the surface opposite to the surface of the At foil.

Next, the above two types of prepreg materials were left in a room with a temperature of 25C and a humidity of 70% RH, and changes in shape over time were observed. The observation results are shown in Table 2.

Table 2 From Table 2 above, prepreg materials of the present invention (sample & 7
) Id, it can be seen that the occurrence of curling and the lifting of the scrim cloth are extremely rare.

[Brief explanation of the drawing]

The figure is a sectional view showing a typical example of a double-sided release sheet according to the present invention. ? rp+number is as in F. DESCRIPTION OF SYMBOLS 1... Paper base material, 2... Aluminum foil, 3... Adhesive layer, 4,4'... Undercoat layer, 5.5'... Child l
I ablation layer. Oji Paper Co., Ltd. (Jishi Co., Ltd.) Representative Patent Attorney: Roben Aoki, 31μm Attorney Kazuyuki Nishidate, Attorney Yukio Uchida, Patent Attorney Akiyuki Yamaguchi

Claims (1)

[Claims] 1. A paper base; a release agent coating layer formed on one side of the paper base; and an aluminum foil laminated on the other side of the paper base; 11, characterized in that it has a coating layer of a release agent formed thereon.
11 release sheet. 2. For reinforcing on one side of a release sheet: In a prepreg material supporting a fiber prepreg, as a release sheet, a paper base material and a φ0 release agent coated in the shape of 11η on one side of the paper base material are used as a release sheet. 1 and aluminum laminated to the curved surface of the above paper material!・Both 11 having a foil and a coating layer of a peeling agent formed on the surface of this aluminum foil
1i Ill A prepreg material characterized in that it is made by using four sheets and holding the above prepreg on the 1111 side opposite to the aluminum foil bonding side.