KR101561287B1 - Rtm molding method using sueface protecting layer - Google Patents

Abstract

More particularly, the present invention relates to an RTM molding method using a surface protective layer, and more particularly, to a method of molding an RTM using a surface protective layer, The present invention relates to an RTM molding method using a surface protection layer which does not require any special facility investment or modification and which does not require the development of a special purpose resin and thus has excellent appearance characteristics with suppressed visibility and pinholes without increasing the process cost.

Description

TECHNICAL FIELD [0001] The present invention relates to a RTM molding method using a surface protective layer,

More particularly, the present invention relates to an RTM molding method using a surface protective layer, and more particularly, to a method of molding an RTM using a surface protective layer, The present invention relates to an RTM molding method using a surface protection layer which does not require any special facility investment or modification and which does not require the development of a special purpose resin and thus has excellent appearance characteristics with suppressed visibility and pinholes without increasing the process cost.

Generally, fiber reinforced resin (FRP), among them carbon fiber reinforced resin (CFRP), is used in various fields as a composite material having light weight and high mechanical properties.

As a method for molding a fiber reinforced resin, there is known a method of loading a prepreg which is an intermediate material in which a reinforcing fiber base material is previously impregnated with a resin, onto a mold frame and curing the resin impregnated in the reinforcing fiber base material in an autoclave. A plurality of prepregs are stacked and stacked on a mold.

However, recently, as can be seen from FIG. 2 which is a process drawing according to a conventional resin transfer molding (RTM) molding method, a reinforcing fiber base material made of a reinforcing fiber fabric or the like is loaded on a mold frame (S100) ) After depressurizing the inside of a mold frame, a thermosetting resin having fluidity or a thermoplastic resin having fluidity is injected into the mold, the resin is impregnated into the reinforcing fiber base, and the resin is cured (S400) after the mold 300 is widely used because a high-quality molded article can be obtained with a short molding cycle.

This RTM molding method has a problem of low productivity because it takes a long time for molding. In order to improve the productivity, when resin is injected without controlling the flow rate, the resin flows into the mold at a flow rate depending on the pressure of the resin, so that the resin is filled in the mold in a relatively short time. However, since the reinforcing fiber base material is disturbed by the resin, There is a problem that a lot of voids and pin-holes are generated on the surface of the molded product.

Particularly, when the pressure of the resin is injected at a high pressure in order to shorten the molding time, the textile structure itself of the reinforcing fiber base is liable to be disturbed and the resin flows in the mold at high speed, In some cases, the order of the flow changes and large voids may occur. In addition, as the flow speed increases, the gas may not escape between the fabrics, and the fibers may stay and cause defects on the surface as a pinhole. In addition, a reaction gas may be generated from the reactive resin during the curing process, or a fine gas already contained in the resin may grow to grow into a void or a pinhole.

To solve this problem, a method has been proposed in which a plurality of injection ports of an RTM molding apparatus are designed and a random mat layer is introduced between the fiber reinforced substrates to adjust the flow rate of the resin (Korean Patent Laid-Open No. 10-2006-0134105) . However, this method requires a new RTM molding apparatus to be designed and manufactured, and there is a problem that the existing equipment needs to be replaced, and that the random matte layer is included in the reinforced base material, thereby causing the property of the FRP to deteriorate.

This problem is caused by a thermoplastic and thermosetting resin having a complicated temperature control and a long curing time. In order to solve such a problem, a method of using an energy ray-curable resin having a short viscosity and a short curing time has been proposed Open Patent Publication No. 10-2009-0018176). However, this method also requires capital investment for application of energy ray curing system, and there is a cost problem to design and purchase expensive energy ray curing resin. Further, in the case of a molded article molded from a low molecular weight energy ray-curable resin, there is a problem that the low molecular weight oligomer bonds are decomposed during prolonged use and the physical properties are lowered.

Korean Patent Publication No. 10-2006-0134105 Korean Patent Publication No. 10-2009-0018176

It is an object of the present invention to provide an RTM molding method using a surface protective layer having a small number of voids and pinholes and a good appearance property during a curing process of a resin .

In addition, the existing facilities can be used as it is because of the introduction of the surface protection layer, so there is no need to invest in equipment or change, and there is no need to develop a special purpose resin, and the surface protection Layer molding method using the RTM molding method.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

The object of the present invention is achieved by a method for manufacturing a semiconductor device comprising the steps of: placing a cured surface protective layer in an RTM mold; a second step of laminating a reinforcing base material on the surface protective layer; And a fourth step of forming the surface protection layer.

Here, the surface protection layer is maintained in a B-stage state.

Preferably, the glass transition temperature of the surface protective layer is 20 ° C to 200 ° C.

Preferably, the thickness of the surface protection layer is in the range of 1 탆 to 1000 탆.

Preferably, the adhesive force of the surface protective layer is 1 gf / in to 200 gf / in.

Preferably, the reinforcing substrate is carbon fiber, glass fiber or aramid fiber.

Preferably, the resin forming the surface protective layer is a thermosetting resin or a thermoplastic resin.

Preferably, the surface protective layer is coated on a release film, dried and then laminated with another release film, wherein the release film is used in a state where the release film is removed in the first step.

Preferably, the release film is made of a material selected from the group consisting of polyester, transparent polyimide, polyamide, polyethersulfone, polyphenylene sulfide, polyether ketone, polyetheretherketone, preacetylcellulose, polyetheramide, polyethylene naphthalate, And polycarbonate is subjected to a release treatment.

Preferably, the releasing film has a difference in peeling force of 10 gf / in or more.

According to the present invention, it is possible to reduce the number of voids and pinholes generated in the curing process of the resin and to have excellent appearance characteristics, and the existing facilities can be used as it is by introducing the surface protective layer, It is possible to provide an RTM molding method using a surface protection layer which is excellent in appearance and in which the appearance and pinholes are suppressed without increasing the process cost.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a process diagram according to an RTM molding method according to an embodiment of the present invention.
Fig. 2 is a process diagram according to a conventional RTM molding method.
3 is a cross-sectional view of the surface protective layer prepared before being attached to the RTM mold.
4 is a cross-sectional view of a surface protective layer used when attached to an RTM form.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

Unless otherwise stated, all percentages, parts, and percentages are by weight. It will also be understood that when an amount, concentration, or other value or parameter is given in any one of a range, a preferred range, or a list of preferred upper limits and preferred lower limits, it is understood that any upper limit range, It should be understood that specifically all ranges formed from any pair of range limits or desirable values are to be understood. Where a range of numerical values is referred to in this specification, unless otherwise stated, the range is intended to include all the integers and fractions within the endpoint and its range. The scope of the present invention is not intended to be limited to the specific values that are mentioned when defining the scope.

When the term "about" is used to describe the endpoint of a value or range, it is to be understood that the present disclosure encompasses the particular value or endpoint mentioned.

As used herein, the terms "comprise," "include," "including," "including," "containing," " Having ", " having ", " having ", or any other variation thereof, are intended to cover an inclusion not exclusive. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to such elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus It is possible. Also, unless explicitly stated to the contrary, "or" does not mean " comprehensive " or " exclusive "

Where an applicant defines an invention or portion thereof in an open term such as "comprising ", it should be readily understood that the description should be interpreted as describing the invention using the term" consisting essentially & do.

1, which is a process diagram of an RTM molding method according to an embodiment of the present invention, a resin transfer molding method (RTM) molding method using a surface protective layer according to the present invention comprises: A second step S2 of laminating the reinforcing base material on the surface protective layer, a third step S3 of tightening the mold frame, and a fourth step S4 of injecting and hardening the resin Do the inclusion.

Hereinafter, this will be described in detail.

 [Preparation step of surface protective layer]

3, which is a cross-sectional view of the surface protective layer prepared before being attached to the RTM mold, and FIG. 4, which is a cross-sectional view of the surface protective layer used when attached to the RTM form, the surface protective layer 100 used in the present invention is a release film 200 ) May be preliminarily cured by applying a resin for RTM on the release film 300, and then the release film 300 having a different releasing force may be used. Specifically, the surface protective layer 100 refers to a resin layer on the B-stage previously cured between the release films.

The release film may be at least one of polyester, transparent polyimide, polyamide, polyether sulfone, polyphenylene sulfide, polyether ketone, polyether ether ketone, preacetyl cellulose, polyether amide, polyethylene naphthalate, polypropylene and polycarbonate It is preferable that one surface is subjected to a releasing treatment.

The release film used in the surface protective layer preparation step preferably has a difference in peel strength of 10 gf / in or more. If the difference in peel strength is less than 10 gf / in, the shape of the surface protective layer may not be maintained during the process of disposing the surface protective layer on the mold, which may result in deterioration of the appearance characteristics.

The surface protective layer is preferably a B-stage phase. When the surface protective layer is in the A-stage, the film is not kept in the form of a film, and thus a problem occurs. In the case of the C-stage, all of the resin is cured so that adhesion with the reinforced substrate is difficult. There arises a problem that a pinhole or pinhole occurs in the same manner.

The surface protective layer preferably has a glass transition temperature of 20 to 200 캜. If the glass transition temperature of the surface protective layer is less than 20 ° C, the surface of the molded article may be damaged easily due to the soft surface of the resin even after the resin is cured. If the glass transition temperature exceeds 200 ° C, the molded article becomes excessively hard There arises a problem that it is easily damaged by impact.

The thickness of the surface protective layer is preferably 1 m to 1000 m. When the thickness of the surface protective layer is less than 1 탆, it is difficult to control the thickness of the film in the manufacturing process. Thus, the uniformity of the product may be changed and the workability is poor. When the thickness exceeds 1000 탆, The physical properties are lowered.

It is also preferable that the adhesive strength of the surface protective layer on the B-stage is from 1 gf / in to 200 gf / in. If the adhesion of the surface protective layer is less than 1 gf / in, the surface protective layer may not be fixed to the mold when the surface protective layer is disposed on the mold, and the uniformity of the RTM molded article may be lowered. When the adhesive strength is more than 200 gf / in If the surface protective layer is misaligned, rework is difficult and workability is lowered.

The resin forming the surface protective layer is preferably a thermosetting resin or a thermoplastic resin. Examples of the thermosetting resin include polyimide resins such as epoxy resins, unsaturated polyester resins, unsaturated polyester resins, polyvinyl ester resins, phenol resins, guanamine resins and bismaleimide triazine resins, furan resins, polyurethane resins, A melamine resin, a urea resin, and an amino resin. Especially, it is more preferable to use an epoxy resin which is a thermosetting resin in view of excellent mechanical properties and heat resistance characteristics.

As the epoxy resin, a compound having a plurality of epoxy groups in the molecule is used. Particularly, amines, phenols and compounds having carbon-carbon double bonds are preferably used. For example, bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins and bisphenol S type epoxy resins, phenol novolak type epoxy resins and cresol novolak type epoxy resins, Or a combination thereof is preferably used.

As the curing agent to be used in such an epoxy resin composition, any compound having an active group capable of reacting with an epoxy group can be used, but a compound having an amino group, an acid anhydride group and an azide group is preferably used. Specifically, dicyandiamide, various isomers of diaminodiphenylsulfone, and amino benzoic acid esters are preferably used.

[RTM molding method]

The RTM molding method according to the present invention comprises a first step (S1) of arranging a cured surface protective layer in advance in an RTM mold, a second step (S2) of laminating a reinforcing base material on the surface protective layer, A third step (S3), and a fourth step (S4) of injecting and hardening the resin.

More specifically, the release film 200 of the surface protective layer 100 in a state of being laminated with the release film prepared in the above method is removed, and the release film 200 is placed on the bottom surface of the mold, and then the other release film 300 is removed (S1), the reinforcing base material is placed on the surface protection layer (S2), and the mold frame is tightened (S3). The resin is injected into the mold to cure the resin (S4) and demold (S5) to obtain a molded article.

The reinforcing base material in the second step is preferably at least one reinforcing base material selected from the group consisting of carbon fiber, glass fiber, aramid fiber, metal fiber, boron fiber, alumina fiber and silicon carbide high strength synthetic fiber. In particular, carbon fiber, glass fiber or aramid fiber is more preferable.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[Example 1]

To 100 parts by weight of a bisphenol A type epoxy resin, 30 parts by weight of a polyamine type polyamine curing agent was added and stirred for 30 minutes. The stirred tank liquid was applied to a 38 탆 PET release film (XD5BR, manufactured by Toray Industries, Inc.), and was pre-cured at 80 캜 for 3 minutes. Thereafter, a 50 탆 PET release film (XP3YP, To prepare a surface protective layer having a thickness of 5 mu m.

After the release film (XP3YP) of the prepared surface protective layer was removed, the surface protective layer was uniformly arranged on a mold and then the other release film (XD5BR) was removed to complete the arrangement of the surface protective layer. The UD fabric was placed thereon at 0 ° / 90 ° / 90 ° / 0 °, and then the mold was clamped. Then, the prepared RTM resin was injected at 25 캜 for 10 minutes at a vacuum pressure of -0.1 MPa and an injection pressure of 0.4 MPa. After the injection was completed, the mold was heated to 150 DEG C and cured at 150 DEG C for 3 minutes. After the curing was completed, the mold was cooled to room temperature and then demolded to prepare RTM molded articles having a thickness of 1 mm, a width of 300 mm and a length of 400 mm.

[Example 2]

A surface protective layer having a thickness of 100 mu m was prepared with the same liquid as in Example 1. [

After the release film (XP3YP) of the prepared surface protective layer was removed and uniformly placed on a mold, the other release film (XD5BR) was removed to complete the arrangement of the surface protective layer. The UD fabric was placed thereon at 0 ° / 90 ° / 0 ° / 90 ° / 90 ° / 0 ° / 90 ° / 0 ° and the mold was clamped. The prepared RTM resin was then injected at 25 캜 for 20 minutes at a vacuum pressure of -0.1 MPa and an injection pressure of 0.4 MPa. After the injection was completed, the mold was heated to 150 DEG C and cured at 150 DEG C for 3 minutes. After the curing was completed, the mold was cooled to room temperature and then demolded to prepare an RTM molded product having a thickness of 2 mm, a width of 300 mm and a length of 400 mm.

[Comparative Example 1]

An RTM molded article having a thickness of 1 mm, a width of 300 mm and a length of 400 mm was prepared in the same manner as in Example 1, without introducing the surface protective layer.

[Comparative Example 2]

An RTM molded article having a thickness of 2 mm, a width of 300 mm and a length of 400 mm was prepared in the same manner as in Example 2 without introducing the surface protective layer.

[Comparative Example 3]

In Example 1, the surface protective layer was pre-dried at 150 占 폚 for 3 minutes to prepare a C-stage surface protective layer. An RTM molded article having a thickness of 1 mm, a width of 300 mm and a length of 400 mm was prepared in the same manner as in Example 1.

[Comparative Example 4]

In Example 1, the surface protective layer was pre-dried at 50 占 폚 for 3 minutes to prepare an A-stage surface protective layer, and an RTM molded article having a thickness of 1 mm, a width of 300 mm and a length of 400 mm was prepared in the same manner as in Example 1.

[Comparative Example 5]

An RTM molded article having a thickness of 1 mm, a width of 300 mm and a length of 400 mm was prepared in the same manner as in Example 1,

The properties of the RTM molded articles according to Examples 1 to 2 and Comparative Examples 1 to 5 were measured through the following experimental examples, and the results are shown in Table 1 below.

 [Experimental Example 1: Surface void and pinhole size measurement test]

The sizes of the vias and pinholes formed on the surface of the RTM molded articles prepared in the above Examples and Comparative Examples were checked by a microscope and evaluated according to the following criteria according to the size of the vaults or pinholes generated on the surface.

○: the largest of the voices and pinholes, the average of 10 is less than 500 μm

[Delta]: the largest of the voids and pinholes, the average of 10 is 500 [mu] m or more and less than 1000 [

Χ: the largest of the voices and pinholes, the average of 10 is more than 1000 μm

[Experimental Example 2: Surface void, pinhole count test]

The surfaces of the RTM molded articles prepared in the above Examples and Comparative Examples were examined by a microscope and evaluated according to the following criteria according to the number of voids and pinholes generated on the surface.

∘: Less than 10 pieces of 500 ㎛ or more of the board or pin hole

[Delta]: More than 500 mu m in the void or pinhole was 10 or more and less than 50

Χ: 50 or more of 500 ㎛ or more of the board or pinhole

[Experimental Example 3: Surface resin impregnability test]

The surfaces of the RTM molded articles prepared in the above Examples and Comparative Examples were confirmed by a microscope and evaluated according to the following criteria. Herein, a portion of the surface of the molded product which was not impregnated with 500 mu m or more was defined as the non-impregnated portion.

○: Less than 5 non-impregnated parts on the surface.

[Delta]: Less than 10 non-impregnated portions on the surface at 5 or more points.

Χ: More than 10 non-impregnated parts on the surface.

[Experimental Example 4: Test of surface protective layer reworkability]

When the prepared surface protective layer was placed in a mold, the number of times of uniform reworking was measured and evaluated according to the following criteria.

○: 3 times or more

?: 1 to 2 times

Χ: No rework

[Experimental Example 5: Measurement of Adhesion at Room Temperature]

The surface of the copper foil (Mitsui: 3EC-THE-AT) to be used as an adherend was washed with acetone, and then the surface protective layer Are laminated by reciprocating twice with a 2 kg rubber roller. Thereafter, the samples were left to stand for 20 minutes, and the adhesion was measured at a rate of 300 mm / min at 180 °.

Measure void and pinhole Impregnability Reworkability adhesiveness
(gf / in) size Count Example 1 ○ ○ ○ ○ 16 Example 2 ○ ○ ○ ○ 53 Comparative Example 1 Χ Χ Χ - - Comparative Example 2 Χ Χ Χ - - Comparative Example 3 △ △ Χ Χ 0 Comparative Example 4 Inoperable Inoperable Inoperable Inoperable Not measurable Comparative Example 5 Χ Χ Χ Χ 0.1

As can be seen from the above Table 1, by introducing the surface protection layer according to the present invention, the existing facilities can be used as it is and the appearance characteristics with suppressed voids and pinholes It can be confirmed that this excellent RTM molded article can be manufactured.

However, as can be seen from Comparative Examples 1 and 2, when the surface protective layer is not provided, it can be confirmed that it is difficult to manufacture an RTM molded article having a large void and pinhole, a large number, a reduced surface impregnability and an excellent appearance characteristic.

Also, as can be seen in Comparative Example 3, when the surface protective layer is fully cured to form a C-stage state, voids and pinholes are partially generated, and the surface protective layer is broken It is difficult to rework and the fixed and reinforced base material can not be fixed to the mold frame, so that the resin impregnability is lowered.

Also, as can be seen in Comparative Example 4, when the A-stage state occurs due to insufficient pre-curing of the surface protective layer, the film shape is not maintained and the surface protective layer can not be formed.

As can be seen in Comparative Example 5, when the thickness of the surface protective layer is less than 1 占 퐉, the surface protective layer is also damaged at the time of removing the release film, and such a damaged portion serves as a factor further lowering the appearance characteristics .

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

100: surface protective layer
200: Lower release film
300: upper release film

Claims (10)

A first step of placing a cured surface protective layer in an RTM mold,
A second step of laminating a reinforcing base material on the surface protective layer,
A third step of clamping the mold,
And a fourth step of injecting and hardening the resin,
Wherein the surface protective layer is coated on a release film, cured and then laminated with another release film, wherein the release film is used in a state where the release film is removed in the first step. Way. The method according to claim 1,
Wherein the surface protection layer is maintained in a B-stage state. The method according to claim 1,
Wherein the surface protective layer has a glass transition temperature of 20 占 폚 to 200 占 폚. The method according to claim 1,
Wherein the surface protective layer has a thickness of 1 占 퐉 to 1000 占 퐉. The method according to claim 1,
Wherein the surface protective layer has an adhesive strength of 1 gf / in to 200 gf / in. The method according to claim 1,
Wherein the reinforcing base material is carbon fiber, glass fiber or aramid fiber. The method according to claim 1,
Wherein the resin forming the surface protective layer is a thermosetting resin or a thermoplastic resin. delete The method according to claim 1,
The release film may be formed of a material selected from the group consisting of polyester, transparent polyimide, polyamide, polyether sulfone, polyphenylene sulfide, polyether ketone, polyetheretherketone, preacetylcellulose, polyetheramide, polyethylene naphthalate, polypropylene and polycarbonate Wherein at least one side is subjected to mold releasing treatment. The method according to claim 1,
Wherein the release film has a difference in peel force of 10 gf / in or more.

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