JP4647815B2 - Release sheet for prepreg material molding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a release sheet for molding a prepreg material that can be suitably used for continuous heat molding of carbon fiber reinforced plastics having various shapes such as a cylindrical shape, a U-shape, and an H-shape.
[Prior art]
A prepreg material in which a reinforcing material such as carbon fiber or glass fiber is impregnated with a thermosetting resin such as epoxy resin or phenol resin is thermoformed to continuously obtain a molded product having an arbitrary cross-sectional shape. Up to now, as a release sheet between the prepreg material and the mold, a fluorine sheet, a polymethylpentene resin sheet (including TPX), or a composite sheet obtained by bonding a polymethylpentene resin sheet and polyethylene terephthalate (PET) Has been used. However, when a fluorine sheet is used, there is a problem that the transfer of fluorine to the molded product adversely affects subsequent workability such as reducing the adhesiveness, and there is a problem that the cost becomes high. On the other hand, a polymethylpentene resin sheet is used. In addition, there is a drawback that mechanical properties such as bending elasticity and tensile strength during heating are insufficient.
On the other hand, when a laminated sheet laminated with PET and a polymethylpentene resin sheet is used to supplement the mechanical strength, the mechanical strength is improved, but due to oligomers and abrasion powder precipitated from the PET during heating. A new drawback has arisen that the mold is contaminated.
[0002]
[Problems to be solved by the invention]
An object of the present invention is to provide a release sheet for molding a prepreg material, which is excellent in mechanical strength and does not contaminate the mold with oligomers and abrasion powder precipitated from the release sheet during heat molding.
[0003]
[Means for Solving the Problems]
The present invention is a laminate of a heat-resistant and releasable polyolefin resin film such as a polymethylpentene resin sheet and a resin film such as a polyester resin film, and further has a phenyl group in a skeleton such as a polyphenylene sulfide film. This is based on the knowledge that when the heat-resistant engineering plastic film is provided and laminated on the resin film, particularly the polyester resin film, the above-mentioned problems can be efficiently solved.
That is, the present invention provides a prepreg material comprising a polyolefin resin film having heat resistance and releasability, a resin film, and a heat-resistant engineering plastic film having a phenyl group in the skeleton laminated in this order. A mold release sheet is provided.
The present invention also provides a prepreg characterized by disposing a prepreg material on a polyolefin resin film layer having heat resistance and releasability of the release sheet, heat-press molding, and then peeling the release sheet. A method for molding a material is provided.
[0004]
DETAILED DESCRIPTION OF THE INVENTION
The polyolefin resin film having heat resistance and releasability used in the present invention has heat resistance and releasability with respect to the prepreg material. Specific examples include polymethylpentene resin films and cycloolefin resin films. Of these, polymethylpentene resin films are preferable, and 4-methyl-1-pentene resin films are particularly preferable. These can be easily obtained as Opyuran TPX manufactured by Mitsui Chemicals. Although thickness is arbitrary, it is preferable that it is 10-150 micrometers, More preferably, it is 15-100 micrometers.
In the present invention, it is preferable to use a polyolefin resin film that has been subjected to easy adhesion treatment such as corona treatment, plasma treatment, and blast treatment, preferably corona treatment on one or both sides (preferably on one side). .
The resin film used in the present invention can be used without particular limitation, and examples thereof include films of polyethylene terephthalate (PET), polybutylene terephthalate, polycarbonate, acrylic resin, and the like. Of these, polyester resin films such as polyethylene terephthalate (PET) and polybutylene terephthalate are preferable, and PET is particularly preferable. These are easily available as Lumirror etc. manufactured by Toray Industries, Inc. Although thickness is arbitrary, it is preferable that it is less than 500 micrometers, More preferably, it is 5-120 micrometers.
[0005]
As the heat-resistant engineering plastic film used in the present invention, those having a low oligomer precipitation amount upon heating and excellent mechanical properties upon heating are preferable. As such a film, a polyphenylene sulfide film is preferable, and Torelina manufactured by Toray Industries, Inc. is exemplified. Although thickness is arbitrary, it is preferable that it is less than 100 micrometers, More preferably, it is 5-20 micrometers.
In the present invention, a polyolefin resin film having heat resistance and releasability, a resin film, and a heat-resistant engineering plastic film having a phenyl group in the skeleton are laminated in this order. At this time, it is preferable to laminate the heat-resistant plastic film so that the surface subjected to the easy adhesion treatment faces the polyester resin film. The lamination method can be used without particular limitation as long as it gives heat resistance to the laminated release sheet. When no adhesive is used, there are an ultrasonic fusion method and a heat fusion method. In particular, it is preferable to apply an adhesive layer between the adhesive films.
[0006]
Here, for the adhesion between the heat-resistant plastic film surface and the resin film, polyester resin, urethane resin, polyester-polyurethane resin, acrylic-polyol resin, polyolefin resin, polyisocyanate The resin can be used in any combination, but it is particularly preferable to use the polyester polyol resin and the polyisocyanate resin in combination. On the other hand, polyester resin, urethane resin, polyester-polyurethane resin, acrylic-polyol resin, polyolefin resin, polyisocyanate resin, etc. can be used for adhesion between polyester resin film and heat-resistant engineering plastic film. Although it can be used in combination, it is particularly preferable to use a polyester polyol resin and a polyisocyanate resin in combination. Specifically, aliphatic isocyanate is preferable as the isocyanate resin. In particular, HDI isocyanate is desirable.
[0007]
More specifically, an adhesive composition comprising a polyester polyol resin and a polyisocyanate resin is preferably used for bonding the polyester resin film and the polyphenylene sulfide film.
As the polyisocyanate resin, aliphatic polyisocyanate or the like is preferably used, and HDI polyisocyanate is particularly preferable.
In the present invention, it is particularly preferable to use a solution in which an adhesive is dissolved or dispersed, apply the solution to one side of a resin film, dry the solvent, and then adhere the adherend film in layers.
Such a solution-like adhesive can be applied on a film substrate by a conventional method on a Mayer bar, applicator, silk screen, comma, reverse, direct gravure, microgravure, die, air knife, bar, curtain, spray, blade, etc. It can apply by the method using various coating apparatuses.
[0008]
In the present invention, the thickness of the adhesive layer is not particularly limited, but is preferably about 0.05 to 20 μm, more preferably 0.1 to 10 μm, and particularly preferably 0.5 to 5 μm.
The laminate thus prepared is preferably one that is 90 ° bent heat resistant (180 ° C. × 2 hr), does not float between the films, has high bending elasticity, and is not easily curled.
Although the thickness of the laminated body of this invention is arbitrary, it is preferable that it is 10-800 micrometers, More preferably, it is 25-250 micrometers, More preferably, it is less than 100-200 micrometers.
In the present invention, the prepreg material is formed by placing the prepreg material on the polyolefin resin film layer having heat resistance and releasability of the release sheet, molding by heating and pressing, and then peeling the release sheet. It is good to do. At this time, two release sheets are prepared, arranged so that the heat-resistant engineering films of each sheet face each other, and prepreg material is sandwiched between them to perform heat and pressure molding, and then the release sheet is peeled off. Good. The heat and pressure molding is preferably performed by hot pressing in a mold, but the molding method can be used without any particular limitation, and in particular, the molding is more preferably performed by the pultrusion method.
[0009]
The prepreg material used here may be any material that can be suitably used to form a fiber reinforced plastic, for example, phenol-epoxy resin, bismaleimide-triazine resin, polyimide resin, epoxy resin, phenol resin, Either triazine resin or polyamide resin may be used alone or in combination, and may be combined with carbon fiber, synthetic fiber, glass fiber or the like. Moreover, when making it multilayer, you may combine. Among these, it can use suitably for the prepreg using an epoxy resin especially.
In the above molding method, one or more release sheets may be used depending on the shape of the final molded product.
[0010]
【The invention's effect】
According to the present invention, there is provided a release sheet for molding a prepreg material that is excellent in mechanical properties and does not contaminate the mold with oligomers or abrasion powders precipitated from the release sheet during heat molding. And the reinforcement | strengthening member of various forms can be shape | molded efficiently by using this release sheet and prepreg.
Next, an example explains the present invention.
[0011]
【Example】
Example 1
A laminate having the following three-layer structure was prepared as follows.
(1) TPX: Mitsui Chemicals, Opulan TPX, X44B # 50 (thickness 50 μm) was used as the polyolefin resin film having the lowest layer heat resistance and releasability.
(2) As an intermediate layer resin film, PET: manufactured by Toray Industries, Inc., Lumirror, # 100S10 (thickness: 100 μm) was used.
[0012]
(3) A polyphenylene sulfide film (PPS: manufactured by Toray Industries, Inc., Torelina, # 9-3030 corona (thickness 9 μm)) was used as a heat-resistant engineering plastic film having a phenyl group in the uppermost layer skeleton.
First, polyester-polyol resin (Adlock RU-77, manufactured by Rock Paint Co., Ltd.) / Aliphatic polyisocyanate (H-7, manufactured by Rock Paint Co., Ltd.) = 87/13 in terms of solid content mass ratio, as a dilution solvent A toluene / methyl ethyl ketone = 1/1 mixed solvent was prepared by stirring and dissolving so that the weight ratio was 26/74. This was applied to a PET film as an intermediate layer by a usual method using a Meyer bar and dried (thickness: 4 μm). A PPS film was laminated thereon and heat-pressed to prepare a two-layer laminate. Next, polyether polyurethane resin (Takelac A-610, manufactured by Takeda Pharmaceutical Co., Ltd.) / HMDI-based isocyanate (Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.) = 87.8 / 12.2 in terms of solid content mass ratio, As a diluent solvent, a mixed solvent of ethyl acetate / toluene = 1/1 was prepared by stirring and dissolving so that the weight ratio was 26/74. This was applied to the PET film layer side of the three-layer laminate formed earlier by a usual method using a Mayer bar and dried (thickness 4 μm). On top of that, a sticky release film (NT25, manufactured by Panac Co., Ltd.) was attached to one side of the TPX film to prevent corona show-through, and after the corona discharge treatment was performed on the TPX film side, The treated surfaces were stacked and heat-pressed, and the release film having adhesiveness was peeled off to prepare a release sheet composed of a 5-layer laminate.
[0013]
When the 180 ° turn-back test was performed on the PPS side, it was 3.82 N / 15 mm at room temperature and 1.67 N / 15 mm in hot air at 100 ° C.
Moreover, the 100 ° C. tear evaluation results were 85 ° under the aging conditions (45 ° C. × 2 days) and 85 ° under the aging conditions (45 ° C. × 7 days).
After heating in hot air at 190 ° C. for 3 hours, the surface of the PPS film was visually observed, and the surface state before and after heating was compared.
[0014]
Example 2
A release sheet composed of the three-layer laminate of the present invention was prepared in the same manner as in Example 1 except that the amount of aliphatic isocyanate (manufactured by Adlock Co., Ltd.) was 20 parts by weight.
When the 180 ° turn-back test on the PPS side was performed, it was 3.63 N / 15 mm at room temperature and 1.47 N / 15 mm in hot air at 100 ° C.
Moreover, the 100 ° C. tear evaluation result was 90 ° under the aging condition (45 ° C. × 2 days) and 85 ° under the aging condition (45 ° C. × 7 days).
[0015]
Comparative Example 1
In the same manner as in the examples, a release sheet composed of a two-layer laminate composed of the lowermost layer and an intermediate layer was prepared.
After heating in hot air at 190 ° C. for 3 hours, the surface of the PET film was visually observed, and the surface state before and after heating was compared. As a result, white powder-like oligomers were deposited on the entire surface of the intermediate layer. It was.
[0016]
Example 3
When an epoxy prepreg using a roll-shaped carbon fiber cloth is continuously molded using a conventionally known method using the release sheet prepared in Examples 1 and 2, the release film and the prepreg are closely adhered to each other during molding. In addition, it could be processed without entrainment of air that would cause inconvenience in practical use and appearance, while exhibiting good mold releasability. After molding, the release film could be removed without difficulty from between the molded products, showing good release properties. Also, the mold was not soiled.

Claims (3)

A release sheet for molding a prepreg material, wherein a polyolefin resin film, a polyester resin film, and a polyphenylene sulfide film having heat resistance and releasability are laminated in this order.   The release sheet according to claim 1, wherein the polyolefin resin film is subjected to easy adhesion treatment on one side. The release sheet according to claim 1 or 2 , wherein each film is bonded with an adhesive.