JP6443183B2 - Bagging film - Google Patents

Description

  The present invention relates to a bagging film, and more particularly to a bagging film used for molding a composite material having excellent heat resistance, high flexibility and elongation, and excellent bagging workability.

  Composite materials, especially composite materials reinforced with fibers (FRP), are materials in which high-strength fibers such as carbon fibers, glass fibers, aramid fibers, boron fibers, and metal fibers are impregnated with resins. It is used as a structural member for ship applications, building applications, aerospace applications, wind turbines for wind power generation, and the like.

  Especially, carbon fiber reinforced resin (CFRP) which uses carbon fiber as a reinforced fiber is a material useful as various components of civil aircraft because it is lightweight and has high strength.

  Known CFRP molding methods include vacuum (reduced pressure) bag molding, pressure bag molding, and autoclave molding. Vacuum (reduced pressure) molding method involves impregnating and laminating resin on reinforcing fibers on a mold, covering the outermost layer with a bagging film, sealing, and then depressurizing to adhere the film to the laminated surface and defoaming And then heat-curing. The pressure bag molding method is a method in which a reinforcing fiber is impregnated and laminated on a mold, covered with a bagging film, and air or steam is sent between the pressure plate and the bag and cured while being pressurized. There is a feature in that it can be pressurized to a higher pressure than the vacuum bag molding method is pressurized at atmospheric pressure. The autoclave molding method is a molding method that is generally widely used based on the same principle as the vacuum bag molding method. A laminated body in which prepregs composed of carbon fibers and a tough epoxy resin are stacked one by one in an autoclave. Pressurize and heat to cure. When curing in an autoclave, a bagging film is used to cover the prepreg and reduce the pressure inside.

  In recent years, a method called a VaRTM molding method has been used as a new molding method, and a large FRP structure having a length of 10 m or more has been put into practical use. In other words, a reinforcing fiber fabric is placed on the mold, the whole is covered with a bagging film, the inside is evacuated, and a low-viscosity thermosetting resin is injected at room temperature to diffuse and impregnate the resin between the fibers. This is a method of curing after curing.

  The bagging film used when molding fiber reinforced resin in the autoclave molding method is required to have flexibility and elongation in the operation of wrapping the prepreg, and if it is not flexible, it will follow the unevenness when it adheres to the prepreg by vacuuming. Without such a problem, there is a problem that it becomes a stretch, a bridge, or breaks. So far, workers have made a bag on the bagging film in advance and devised measures to prevent the bagging film from stretching and bridging when evacuated, but when manufacturing a three-dimensional composite material, Bagging work is troublesome and requires a lot of man-hours. On the other hand, at the time of evacuation, rapid partial elongation occurs at the stretched portion or bridge portion of the film due to reduced pressure, and tearing or pinholes are likely to occur at that portion. Similarly, tearing and pinholes are generated due to film elongation even under high pressure in an autoclave. Therefore, elongation is necessary in bagging work, but strength is also necessary. Furthermore, since the autoclave molding method maintains a high temperature for a long time, if the heat resistance of the film is inferior, deterioration due to thermal decomposition of the resin tends to occur.

  As an example of use of a bagging film, for example, Patent Document 1 has a description example of a bagging film made of a rubber sheet made of silicone. However, although it has excellent heat resistance and elongation, it has a drawback that it is generally expensive, and further vacuum It has the disadvantage of poor adhesion to the sealant tape used for sealing. Patent Document 2 discloses the use of nylon or polyolefin film as a bagging film, but there is a description of a film selected from gas permeability, heat resistant temperature, humidity, etc. There is no mention of detailed characteristics including characteristics.

JP 2003-11136 A JP 2011-83975 A

  The present invention relates to a bagging film, the purpose of which is flexible and easy to stretch, is easy to perform bagging work, and at the same time, it is difficult for high pressure breaks and pinholes to occur in the autoclave molding method, It is to provide a bagging film having thermal stability at high temperature.

In order to achieve the above object, the present invention has the following configuration.
(1) A bagging film comprising a resin composition comprising a polyamide resin and a thermoplastic elastomer as main components, wherein the bagging film is used for molding a fiber-reinforced composite material.
(2) The polyamide resin is at least one selected from nylon 6, a copolymer having nylon 6 as a main component, nylon 66, and a copolymer having nylon 66 as a main component. Bagging film.
(3) The bagging film according to (1) or (2), wherein the thermoplastic elastomer is a thermoplastic polyester elastomer and / or a thermoplastic polyamide elastomer.
(4) The bagging film according to any one of (1) to (3), wherein the content of the polyamide resin in the resin composition is 50 to 80% by weight and the content of the thermoplastic elastomer is 20 to 50% by weight.
(5) The bagging film according to any one of (1) to (4), wherein the resin composition contains at least one selected from hindered phenols and hindered amines as an antioxidant.

  According to the present invention, since a resin composition containing a polyamide resin and a thermoplastic elastomer is used as a bagging film at the time of fiber reinforced resin molding, it has a high elongation and a low Young's modulus. Because of its high strength and high strength at the same time, it is not subject to tearing or pinholes due to abrupt stress in autoclave molding and pressure, and it has excellent thermal stability at high temperatures. Thus, a bagging film free from embrittlement by the method can be obtained.

  The bagging film of the present invention is a film made of a resin composition comprising a polyamide resin and a thermoplastic elastomer.

  Polyamide resin is generally called nylon, but nylon 6, nylon 66, nylon 46, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer (nylon 6,66), nylon 6/12 copolymer Examples include coalescence (nylon 6,12), nylon 6/66/610 copolymer (nylon 6,66,610), nylon MXD6, nylon 6T copolymer, nylon 6 / 6T copolymer, etc. Without limitation, mixtures thereof are also included. Among these, nylon 6, a copolymer containing nylon 6 as a main component, nylon 66, and a copolymer containing nylon 66 as a main component are selected in terms of balance of physical properties, availability, cost, and handleability. It is preferable to use at least one, and specifically, for example, nylon 6, nylon 66, and nylon 6/66 copolymer are preferable.

  In addition, as a polyamide copolymer, monomers such as aliphatic dicarboxylic acid, aromatic dicarboxylic acid, aliphatic diamine, aromatic diamine, and aminocarboxylic acid other than the monomers constituting the copolymer described above are copolymerized. It can be used as a component.

  Specific polyamide resins include “Amilan” and “Rilsan” manufactured by Toray Industries, Inc. “UBE Nylon”, “UBE Nylon” 6, “UBE Nylon” 66 manufactured by Ube Industries, Ltd., “Asahi Kasei Chemicals Corporation” Leona, Mitsubishi Engineering Plastics Co., Ltd. “Reny”, “Novamid”, Unitika Ltd. Unitika Nylon 6, Unitika Nylon, “Maraniel”, Toyobo Co., Ltd. Toyobo Nylon Co., Ltd. Examples thereof include “Ultramid”, Polyplastics Co., Ltd. and Polyplastic Nylon.

  The thermoplastic elastomer in the present invention may be polyester, polyamide, styrene, olefin, vinyl chloride, urethane, nitrile, fluorine, silicone, etc., depending on the type of polymer forming the hard segment. Polyesters and polyamides are preferred in terms of dispersibility, film-forming properties, heat resistance, and heat stability when mixed with polyester, and polyesters are more excellent because of their excellent mechanical properties such as high elongation and high melting point. preferable.

  As polyester-based and polyamide-based thermoplastic elastomers, a resin constituting a hard segment is an aromatic polyester or polyamide, and a component constituting a soft segment is a block copolymer made of a polyether or an aliphatic polyester.

  Specific examples of thermoplastic polyester elastomers include “Hytrel” manufactured by Toray DuPont Co., Ltd., “Perprene” manufactured by Toyobo Co., Ltd., “Primalloy” manufactured by Mitsubishi Chemical Co., Ltd., “Teijin Chemicals Co., Ltd.” "Nuberan", Riken Technos Co., Ltd. Hyperalloy "Actimer", DMS "Arniter", etc., as the thermoplastic polyamide elastomer, Daicel Evonik "Daiamide" PAE, Ube Industries, Ltd. Ube Polyamide Elastomer PAE, “Grillon” ELX, “Grillamide” ELY, manufactured by EMS Showa Denko Co., Ltd., Pebax (registered trademark) manufactured by Atofina Japan Co., Ltd. DIC Corporation "Glax" A, Mitsubishi Engineering Plastics Co., Ltd. ) “Novamid” PAE and the like.

  The composition ratio of the polyamide resin and the thermoplastic elastomer of the resin composition in the present invention is preferably a matrix component that forms a continuous phase of the polyamide resin, and the content of the polyamide resin is 50 to 80% by weight. The range whose content rate is 20 to 50 weight% is preferable. When the content of the thermoplastic elastomer is less than 20% by weight, the Young's modulus increases, resulting in a decrease in flexibility and inferior bagging workability. When the content exceeds 50% by weight, the strength gradually decreases and after bagging work. In some cases, excessive elongation may occur under reduced pressure or autoclave pressure, and pinholes and tears may occur.

  The resin composition in the present invention is mainly composed of a polyamide resin and a thermoplastic elastomer, and does not impair the characteristics. If necessary, other thermoplastic resins and various additives may be added in the range of 0 to less than 50% by weight. Can be blended. Examples of the thermoplastic resin include polyolefin resins, polyacrylic resins, polyester resins, and polyamide resins, and examples of additives include organic or inorganic particles, fillers, dispersants, and plasticizers.

  The “main component” in the present invention means that the total content is 100% by weight and the component is contained in an amount of more than 50% by weight.

  The film comprising the resin composition in the embodiment of the present invention is used at a high temperature depending on the molding conditions of FRP. In order to suppress thermal degradation and improve thermal stability when exposed to high-temperature heating for a long time, it is preferable to add a thermal stabilizer to the resin composition. Antioxidants are preferably used as heat stabilizers, and “Irganox” 1010, “Irganox” 1098 (manufactured by Ciba), “Irganox” 1330, phosphite-based, phosphonite-based as hindered phenol-based antioxidants. "Irgaphos" 168 (manufactured by Ciba), "Irgaphos" P-EPQ (manufactured by Clariant or Ciba, "Lowinox" DSTDP (manufactured by Great Lakes) as a thiosine dyst system), and "Nauguard" 445 (manufactured by a Hindered amine system) Uniloy Chemical), “Chimasorb” 944 (Ciba), and others include hydroxylamine, benzofuranone derivatives, acryloyl-modified phenols, etc. Hindered phenolic antioxidants and hindered amine antioxidants are preferred because of their excellent performance as heat stabilizers, and hindered phenolic antioxidants are more preferred because they are less colored at high temperatures. is there.

  The addition amount of the heat stabilizer is in the range of 0.05% by weight to 5.0% by weight with respect to the resin composition. If it is less than 0.05% by weight, the effect as a heat stabilizer is small, and if it exceeds 5.0% by weight, bleeding tends to occur or the resin tends to be colored, which is not preferable.

  In the film made of the resin composition of the present embodiment, a colorant such as a pigment or a dye can be blended as necessary for color matching.

  The method for dispersing the heat stabilizer, colorant and various additives in the resin composition is not particularly limited, but a composition in which these additives are separately dispersed in advance in a polyamide resin or a thermoplastic elastomer (hereinafter referred to as additive master). In general, a method is used in which an additive master is mixed with a resin composition serving as a base at a predetermined concentration when the film is formed. Although there is a method of dispersing each additive alone or mixed in the resin composition or the like, it is preferable to use a master dispersed separately in terms of optimization of dispersion conditions, freedom of added concentration, and the like. The shape is preferably in the form of pellets in terms of transportability to the film forming apparatus, etc., and preferably the same as the pellet size of the polyamide resin or the thermoplastic elastomer base resin.

  A dispersion method is not particularly limited, and a method of melt-kneading the additive and the resin, a method of removing the dispersion medium at the same time of melt-kneading the additive dispersion and the resin, and the like are used. For example, the additive and resin are melt-kneaded by mixing the additive and resin pellets with a tumbler, ribbon blender, “Nauta mixer”, “Henschel” mixer, planetary mixer, etc. A method of melting and kneading with an extruder and cutting the extruded strand to form a master pellet, or a powdered resin and additives are primarily kneaded with a high shear kneader such as a Banbury mixer, kneader, calendar roll, heating kneader, etc. There is a method in which a resin composition is prepared in advance, and this resin composition is mixed with the above-mentioned resin or the other resin to obtain a master pellet as described above.

  The additive concentration in the additive master is not particularly limited, but is preferably a master chip dispersed at a concentration 2 to 100 times the concentration added to the film. The higher the concentration of the master chip, the more advantageous in terms of dispersion processing costs, etc. However, if it is 100 times or more, the master chip may be unevenly distributed when blended with the base resin, which may result in a non-uniform particle dispersion film. Absent.

  The thickness of the bagging film in the embodiment of the present invention is not particularly limited because it depends on the process used, but is preferably 10 to 500 μm, more preferably 20 to 300 μm. If it is less than 10 μm, the waist becomes weak, the strength is insufficient, and the handleability is poor. On the other hand, if it exceeds 500 μm, the strength becomes high, and the weight per area becomes large, so that the handleability is poor.

  The bagging film according to the embodiment of the present invention may have a single layer structure or a laminated film composed of a plurality of layers.

  In film formation, melt extrusion film formation is preferred from the viewpoints of film thickness control, productivity, additive dispersibility, and the like. The film may be any of the methods such as non-stretching with a T die, uniaxial stretching, biaxial stretching, and inflation film formation with a ring die, but non-stretched film formation with a T die and inflation film formation are preferred in terms of physical properties for bagging applications. Used for.

  Since the bagging film of the present invention is excellent in elongation at normal temperature, it is suitably used as a bagging film for use in forming a fiber-reinforced composite material. The fiber-reinforced composite material in the present invention is a material in which a thermosetting resin or a thermoplastic resin is reinforced by a fibrous material composed of long fibers and / or short fibers, and the types of fibers and resins to be used are not particularly limited. . Especially, it is used suitably for the fiber reinforced composite material whose resin is a thermosetting resin.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, it is not limited to a following example.

  Each characteristic was evaluated based on the following measurement method.

(1) Breaking strength, breaking elongation and Young's modulus Using a tensile testing machine ("Tensilon" universal testing machine manufactured by A & D Co., Ltd.), tensile speed 300mm / min breaking strength, breaking elongation and Young's modulus It was measured.

(2) Bagging workability H-shaped steel 10 cm long x 10 cm wide x 30 cm long x 5 mm thick is placed on a 50 cm square x 3 mm thick stainless steel plate as an alternative to the composite material so that the H-shaped steel is covered. After placing a fluorine film (Toyoflon FV, Toray Film Processing Co., Ltd., 50 μm) and breather cloth (OSE-135, OSE Co., Ltd.), and then covering with a bagging film fitted with a vacuum valve The stainless plate and the bagging film were sealed with a sealant tape (SM-5142 manufactured by Cytec) so that air did not leak. The bagging workability at that time was evaluated according to the following rank.
In addition, since the film of this invention is used for both a longitudinal (MD) direction and a width (TD) direction, it is desirable that it is isotropic, and there exists a possibility that it may deteriorate when anisotropy is remarkable. Therefore, the following (circle) -x are judged by a more favorable value about a longitudinal (MD) direction and a width (TD) direction.
○: If the elongation at break is 550% or more and the Young's modulus is 800 MPa or less, the film is easily stretched and has flexibility, and is excellent in bagging work.
Δ: In cases other than ○ or ×, the film stretch and flexibility are slightly inferior, and the bagging workability is good, but the work is somewhat difficult.
X: When the breaking elongation is less than 500% or the Young's modulus exceeds 900 MPa, the film is difficult to stretch and is inferior in bagging workability because it is hard.

(3) Autoclave test Subsequently, after reducing the pressure to 0.01 MPa or less with a vacuum pump connected to a vacuum valve, the temperature was raised from room temperature to 180 ° C. in 4 hours while performing air pressurization at 4 atm in the autoclave. After maintaining at 180 ° C. for 4 hours, the temperature was lowered to room temperature over 4 hours.
After taking out from the autoclave and leaving it in an environment of 23 ° C. and 50% RH for 24 hours, the flexibility and the deterioration state of the bagging film were evaluated according to the following ranks.
○: Flexibility is the same as or slightly lower than before the autoclave is charged, but it has toughness and is difficult to tear.
Δ: When peeled from the stainless steel plate, the film easily breaks due to embrittlement or thinning.
X: Flexibility is reduced due to embrittlement, and air is leaked due to pinholes due to tearing or partial stretching.

[Examples 1 to 15]
(1) Preparation of heat stabilizer masterbatch A mixture of “Irganox” 1330 powder, which is a hindered phenolic antioxidant, and a thermoplastic polyester elastomer (“Hytrel” 4777 manufactured by Toray DuPont Co., Ltd.) in a ribbon blender After thorough mixing, the mixture was supplied to a vented twin-screw extruder, extruded into a strand, and cut to produce a pellet-shaped heat stabilizer masterbatch containing 10% by weight of “Irganox” 1330.

(2) Production of bagging film Nylon 6 (“UBE nylon” 1030B2 manufactured by Ube Industries, Ltd.), nylon 66 (Toyobo nylon T-660X-2 manufactured by Toyobo Co., Ltd.), nylon 6/66 copolymer resin (( 1) “Amilan” CM6021M (nylon 6: 66 = 95: 5 wt%) manufactured by Toray Industries, Inc. (2) “Amilan” CM6151M (nylon 6: 66 = 90: 10 wt%) manufactured by Toray Industries, Inc. 3) “UBE Nylon” 5033B (Nylon 6: 66 = 85: 15 wt%) manufactured by Ube Industries, Ltd. (4) “UBE Nylon” 5034B (Nylon 6: 66 = 80: 20 weight) manufactured by Ube Industries, Ltd. %)) And thermoplastic polyester elastomer (“Hytrel” 4777 manufactured by Toray DuPont Co., Ltd.) and heat stabilizer masterbatch are uniformly mixed in a ribbon blender. After a single screw extruder, filter, ring die, air ring, stabilizers, and supplies the air upward inflation film forming apparatus comprising a winding device, to obtain a film by inflation film forming thick 80 [mu] m.

  The composition of each raw material and the characteristics of the obtained film are shown in the table. The Young's modulus was low, the elongation at break was excellent, the flexibility was good, and the bagging workability was good. Also, good characteristics were maintained after the autoclave test.

[Example 16]
A film having a thickness of 80 μm was obtained in the same manner as in Example 1 by using the raw material composition shown in the table. As shown in the table, the obtained film has a low Young's modulus, excellent elongation at break, good flexibility, excellent bagging workability, but slightly low strength, so it is used in vacuuming and subsequent autoclaves. When the film was stretched partially and adhered to the H-shaped steel by pressurization at, the film was partially thinned and the film strength tended to decrease.

[Example 17]
A film having a thickness of 80 μm was obtained in the same manner as in Example 5 except that the heat stabilizer master batch was not added. As shown in the table, the obtained film was excellent in bagging workability, but after the autoclave test, although there was no hindrance to the peeling work, there was a tendency that it was somewhat easy to tear.

[Comparative Example 1]
An inflation film-forming film having an average thickness of 80 microns was obtained in the same manner as in Example 1 except that nylon 6 resin ("UBE nylon" 1030B2 manufactured by Ube Industries, Ltd.) was used alone. As shown in the table, the obtained film was inferior in bagging workability because of its high Young's modulus and low elongation and hardness.

[Comparative Example 2]
Using nylon 6 resin ("UBE nylon" 1030B2 manufactured by Ube Industries, Ltd.) and nylon 66 (Toyobo nylon T-660X-2 manufactured by Toyobo Co., Ltd.), an average thickness of 80 is obtained in the same manner as in Example 1. A micron inflation film was obtained. As shown in the table, the obtained film was inferior in bagging workability because of its high Young's modulus and low elongation and hardness.

[Comparative Example 3]
An inflation film-forming film having an average thickness of 80 μm was obtained in the same manner as in Example 1 except that a thermoplastic elastomer (“Hytrel” 4777 manufactured by Toray DuPont Co., Ltd.) alone was used. As shown in the table, the obtained film has high elongation at break and low Young's modulus, so it is excellent in bagging workability, but due to its low strength, vacuum drawing and subsequent pressurization in an autoclave As a result, when the film suddenly partially stretched and adhered to the H-shaped steel, the film was partially thinned to generate pinholes.

  The film comprising the resin composition of the present invention has heat resistance and thermal stability, and is excellent in flexibility and elongation characteristics. Therefore, it is suitably used as a bagging film used in the process of producing a fiber-reinforced composite material. .

Claims (4)

A film comprising a resin composition mainly composed of a polyamide resin and a thermoplastic elastomer, wherein the thermoplastic elastomer is a thermoplastic polyester elastomer and / or a thermoplastic polyamide elastomer, and is used when a fiber-reinforced composite material is molded. A bagging film characterized by that. 2. The bagging film according to claim 1, wherein the polyamide resin is at least one selected from nylon 6, a copolymer having nylon 6 as a main component, nylon 66, and a copolymer having nylon 66 as a main component. The bagging film according to claim 1 or 2 , wherein the content of the polyamide resin in the resin composition is 50 to 80% by weight and the content of the thermoplastic elastomer is 20 to 50% by weight. The bagging film according to any one of claims 1 to 3 , wherein the resin composition contains at least one selected from hindered phenols and hindered amines as an antioxidant.