JP3972542B2 - Method for producing fiber reinforced thermoplastic resin molding material using continuous fiber nonwoven fabric - Google Patents

Description

【００３０】
【発明の効果】
本発明における複合繊維糸は樹脂被覆強化繊維糸に比べ、剛性が弱いため、連続繊維糸からなる不織布を作成した際、容易に強化繊維の坪量を高くすることができる。また、本発明の連続繊維不織布において、熱可塑性樹脂は強化繊維糸を被覆しているのではなく、繊維として強化繊維と複合繊維糸をなすため、ニードルパンチ加工が容易に行うことができる。そのため、この複合繊維糸からなる連続繊維不織布を用いた繊維強化熱可塑性樹脂成形材は、優れた機械的特性を得ることができ、かつ成形工程でマトリックス樹脂を添加する必要がないため、成形工程を簡素化することができる。
【図面の簡単な説明】
【図１】本発明に係る連続繊維不織布の製造装置の平面図
【図２】本発明に係る連続繊維不織布の製造装置の側面図
【符号の説明】
１、１’ 糸掛け用ピン
２、２’ ピン配列
３ コンベア
４、９ トラバースガイド
５、１０ トラバース具
６、１１ ガイド管
７、１２ 緯糸および斜交糸用の複合繊維糸
８、１３ 連続繊維糸集合体
１４、１５ 経糸用の複合繊維糸
１６ 熱ローラ
１７ 加圧ローラ
１８ ４軸組布の形態をなす連続繊維不織布[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous fiber nonwoven fabric used for a fiber reinforced thermoplastic resin molding material, and a method for producing a fiber reinforced thermoplastic resin molding material using the continuous fiber nonwoven fabric.
[0002]
[Prior art]
A sheet-like molding material composed of reinforcing fibers, a thermoplastic resin, and a filler is known as a stampable sheet and can be stamped. Stamping molding is a molding method in which the molding material is preheated and softened, then supplied into a heated mold, and pressurized to form, with advantages such as short molding time, small capital investment, and reduced weight of the molded product. This is a molding method that takes advantage of the characteristics of thermoplastic resins.
Conventionally, as a stampable sheet, a molding material in which a continuous fiber mat or a chopped strand mat subjected to needle punching is impregnated with a thermoplastic resin is known. However, since a thermoplastic resin generally has a high melt viscosity, the resin impregnation property into the reinforcing fibers is poor, and the resin impregnation property decreases more and more when the reinforcing fiber content is increased. For this reason, fiber reinforced thermoplastic resin molded products using these molding materials are characterized by a low direction of mechanical strength, but the content of reinforcing fibers cannot be increased and the molded product must be thick. If this is not the case, satisfactory mechanical properties may not be obtained.
[0003]
Therefore, a sheet obtained by laminating a reinforced fiber yarn woven fabric and a thermoplastic resin film, or a sheet obtained by laminating a woven fabric made of a resin-coated reinforced fiber yarn coated with a thermoplastic resin on the reinforced fiber yarn may be used as a molding material. Has been done. These molding materials can increase the content of reinforcing fibers, but they require a weaving process, and there are limits to improving the impregnation of reinforcing fibers and thermoplastic resin. There is a problem that sufficient mechanical strength in an oblique direction cannot be obtained.
[0004]
On the other hand, regarding continuous fiber non-woven fabric composed of continuous fiber yarns, JP-A-63-66362 comprises a bonded yarn obtained by twisting a heat-bonding yarn to a reinforcing fiber yarn, and the arrangement directions of the bonded yarns are orthogonal to each other. A non-woven fabric having a warp direction and a weft direction that are obliquely crossed is disclosed. However, in this non-woven fabric, the heat-sealing yarn is for maintaining the shape of the non-woven fabric, and is merely wound around the reinforcing fiber to the extent that the impregnation property of the matrix resin does not decrease, and the mechanical strength No further effect of the woven fabric can be expected for reducing the directionality of the fabric.
[0005]
Japanese Patent Application Laid-Open No. 8-325914 discloses a method for producing a molding base material in which glass long fibers and thermoplastic resin long fibers as reinforcing fibers are blown onto a nonwoven fabric from different supply devices. However, this requires a non-woven fabric as a mount and a dedicated supply device for long glass fibers and long thermoplastic resin fibers.
[0006]
Further, Japanese Patent Application Laid-Open No. 11-20059 discloses a resin-coated reinforcing fiber yarn obtained by coating a reinforcing fiber yarn with a thermoplastic resin in four directions of warp material, weft material, and two-way oblique material intersecting in opposite directions. Disclosed is a continuous fiber nonwoven fabric in which each material is fused at the intersection of each material, and a fiber reinforced thermoplastic resin molding material using this continuous fiber nonwoven fabric. Although this continuous fiber nonwoven fabric has excellent characteristics, it requires a resin coating treatment step on the reinforcing fiber yarn, and the resin-coated reinforcing fiber yarn has high rigidity, and there is a limit to increase the basis weight of the continuous fiber nonwoven fabric, Further improvements in work efficiency and mechanical properties are desired.
[0007]
[Problems to be solved by the invention]
The present invention relates to a method for producing a molding material using a continuous fiber nonwoven fabric for obtaining a fiber-reinforced thermoplastic resin molding material, that is, a stampable sheet, having excellent mechanical properties with high mechanical strength and low directionality. It is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, the nonwoven fabric provided for the fiber-reinforced thermoplastic resin molding material is a continuous fiber nonwoven fabric composed of continuous fiber yarns, and the continuous fiber yarns are composed of reinforcing fibers and thermoplastic resin fibers. It consists of a composite fiber yarn, The volume ratio of the said reinforced fiber is 40 to 60%, It is characterized by the above-mentioned.
[0009]
Furthermore, the continuous fiber nonwoven fabric according to the present invention includes a first fiber yarn layer composed of a first continuous fiber yarn group in which a plurality of continuous fiber yarns are arranged in parallel, and the first continuous fiber yarn group in order to enhance mechanical properties. A second fiber yarn layer composed of a second continuous fiber yarn group in which a plurality of continuous fiber yarns obliquely intersecting with each other, and obliquely intersecting the first continuous fiber yarn group from a direction opposite to the second continuous fiber yarn group continuous fiber yarns are provided with a third yarn layer comprising a third continuous fiber yarn groups being more parallel, and a continuous fiber nonwoven fabric in the form of a so-called three framing cloth.
[0010]
Furthermore, in order to further reduce the direction of mechanical strength, in the continuous fiber nonwoven fabric in the form of the above-described triaxial assembly fabric, a plurality of continuous fiber yarns orthogonal to the first continuous fiber yarn group are arranged in parallel. A continuous fiber non-woven fabric in the form of a so-called four-axis assemblage comprising a fourth fiber yarn layer consisting of four continuous fiber yarn groups is preferred.
[0011]
A method for producing a fiber-reinforced thermoplastic resin molding material, ie, a stampable sheet , according to the present invention is a production method characterized in that one or a plurality of the above-mentioned continuous fiber nonwoven fabrics are stacked and heated and pressed to form a sheet at the time of molding. The continuous fiber nonwoven fabric can be molded simply by heating and pressing without adding a thermoplastic resin such as a powder or powder.
[0012]
In the continuous fiber nonwoven fabric of the present invention, after the composite fiber yarn is disposed, the thermoplastic fiber is melted and the composite fiber yarns are temporarily bonded to each other to maintain the shape of the nonwoven fabric, or the composite fiber yarn is formed by needle punching. It is desirable to entangle each other . The continuous fiber nonwoven fabric obtained by needle punching can suppress adverse effects such as oxidation of the thermoplastic resin due to heat.
[0013]
The composite fiber yarn in the present invention only needs to be able to maintain the form of the above-mentioned continuous fiber nonwoven fabric, and may be appropriately selected from any of the forms (a) to (c) shown below.
(A) A mixed yarn obtained by combing reinforced fibers and thermoplastic resin fibers in a fiber state.
(B) A twisted yarn obtained by twisting a reinforcing fiber yarn and a thermoplastic resin fiber yarn.
(C) A combined yarn obtained by simply combining or winding a thermoplastic resin fiber yarn with a reinforcing fiber yarn.
[0014]
The continuous fiber yarn in the present invention is a fiber yarn that is not substantially cut inside the nonwoven fabric, and the fiber length of the reinforcing fiber is long. Moreover, it consists of composite fiber yarns, and the thermoplastic resin is present in the form of fibers relatively uniformly around the reinforcing fibers. Therefore, the continuous fiber nonwoven fabric of the present invention is excellent in resin impregnation even though the reinforcing fiber content is high, and can increase the mechanical strength of a molded material molded using the same.
[0015]
In addition, the continuous fiber nonwoven fabric made of composite fiber yarn is a reinforcing fiber yarn in a molding process for obtaining a molding material, compared to a continuous fiber nonwoven fabric made of resin-coated reinforcing fiber yarn in which a resin is coated around the reinforcing fiber yarn. Since the air inside easily escapes, the resin impregnation property of the continuous fiber nonwoven fabric can be improved, and a molding material having excellent mechanical properties can be obtained.
[0016]
In addition, the volume ratio of the reinforced fiber in this invention can be represented by following Formula (1).
V ₁ = (W ₁ / ρ ₁ ) / (W ₁ / ρ ₁ + W ₂ / ρ ₂ ) × 100 Formula (1)
V ₁ ; volume ratio of reinforcing fiber (%)
W ₁ : Weight of reinforcing fiber (g)
ρ ₁ ; True specific gravity of reinforcing fiber W ₂ ; Weight of thermoplastic resin fiber (g)
ρ ₂ ; When the volume ratio of the true specific gravity reinforcing fiber of the thermoplastic resin fiber is less than 40%, the content of the reinforcing fiber is lowered, and when it exceeds 60%, the impregnation property of the thermoplastic resin into the reinforcing fiber is lowered. In both cases, satisfactory mechanical strength of the molding material may not be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The reinforcing fibers in the continuous fiber nonwoven fabric of the present invention are in the form of long fibers, and examples of the reinforcing fibers include glass fibers . The count of the reinforcing fiber is not particularly limited, and may be selected depending on the use of the continuous fiber nonwoven fabric .
[0018]
Examples of the thermoplastic resin constituting the thermoplastic resin fiber in the continuous fiber nonwoven fabric of the present invention include polyamide resins such as nylon 6, nylon 12, nylon 66, and aromatic nylon, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyethylene and polypropylene. Examples thereof include olefin resins such as polyether ether ketone resins, polyether imide resins, polyether sulfone resins, polyphenylene sulfide resins, and polycarbonate resins. In addition, you may add a coloring agent, a filler, a stabilizer, a flame retardant, an antistatic agent, a crystallization agent, etc. to the said thermoplastic resin fiber suitably.
[0019]
Hereinafter, a manufacturing apparatus and a manufacturing method for a continuous fiber nonwoven fabric in the form of a four-axis assemblage which is an embodiment of the present invention will be described with reference to FIGS.
[0020]
(1) Manufacturing apparatus for 4-axis assemblage The manufacturing apparatus for continuous fiber nonwoven fabric is mainly constructed on the conveyor 3 with an inclination of an angle α relative to the traveling direction of the conveyor 3 and the traveling direction of the conveyor 3. A set of two traverse guides 4, 4 ′ and a pair of traverse guides 9, 9 ′ laid on the conveyor 3 with an inclination α relative to the direction of travel of the conveyor 3, and the direction of travel of the conveyor The traverse tool 5 that reciprocates along the traverse guides 4 and 4 ′ and the traverse tool 10 that reciprocates along the traverse guides 9 and 9 ′ are maintained.
[0021]
The conveyor 3 has pin arrangements 2 and 2 'in which threading pins 1 and 1' are erected at a constant pitch at both ends in the traveling direction.
Further, the traverse tool 5 has a plurality of guide tubes 6 through which the composite fiber yarns 7 serving as oblique and weft threads are inserted, and the composite fiber yarn 12 serving as the oblique and weft threads is inserted into the traverse tool 10. There are a plurality of guide tubes 11, and the guide tubes 6 and 12 are arranged at the same pitch as the pin arrangements 2, 2 ′ standing on the conveyor 3.
[0022]
Further, as shown in FIG. 2, on the left side of the conveyer 3 in the figure, warp yarn rollers each wound with a composite yarn 14 and 15 for warp to be supplied to the conveyer 3 are arranged. . A heat roller 16 and a pressure roller 17 are provided on the right side of the guides 9 and 9 'in the drawing.
[0023]
(2) Manufacturing method of continuous fiber nonwoven fabric In order to manufacture a continuous fiber nonwoven fabric by the continuous fiber nonwoven fabric manufacturing apparatus shown in FIGS. 1 and 2, the conveyor 3 is circulated in the traveling direction while supplying the warp 14 onto the conveyor 3. Let The composite fiber yarns 7 and 12 are inserted into the guide tubes 6 and 11 provided in the traverse tools 5 and 10, and the traverse tools 5 and 10 are reciprocated. When the traverse tools 5 and 10 change direction, each composite fiber yarn is hooked on the yarn hooking pins 1 and 1 '. At this time, by adjusting the circulation speed of the conveyor 3, the reciprocating speed of the traverse tools 5 and 19, and the angles of the traverse guides 4, 4 ′ and 9, 9 ′ with respect to the conveyor 3, the angle of the oblique yarn is ± 45. The continuous fiber yarn assembly 13 can be formed by arranging an oblique yarn that is oblique to the warp and a weft perpendicular to the warp on the warp. Further, the warp yarn 15 is supplied onto the continuous fiber yarn assembly 13, closely contacted with the heat roller 16, removed from the yarn hooking pins 1, 1 ′, heated to a predetermined temperature by the heat roller 16, and turned into a composite fiber yarn. Melt the containing thermoplastic resin. Then, it is pressed down by the pressure roller 17, and the composite fiber yarns are pressure-bonded to form a continuous fiber nonwoven fabric that is a four-axis assembly fabric.
[0024]
In addition, the continuous fiber nonwoven fabric in the form of a triaxial assembly fabric is formed by adjusting the angle -α of the traverse guides 4, 4 ′ and the angle α of 9, 9 ′ of the above-described continuous fiber nonwoven fabric manufacturing apparatus. Can do. Further, the traverse guides 4, 4 ′ or 9, 9 ′ can be used only when the angle is 90 °.
[0025]
【Example】
(1) Creation of 4-axis assembly [Example 1]
A composite yarn consisting of 570 tex glass fiber roving (product name: RS57PR481 manufactured by Nitto Boseki Co., Ltd.) as the reinforcing fiber and 280 tex nylon 6 fiber (filament diameter: 48 μm, number of filaments: 123) as the thermoplastic fiber is combined. 1 and 2 as a warp, a weft and an oblique yarn, and the weft and the oblique yarn are sandwiched between every other upper and lower warps by a device shown in FIG. And a pressure roller are used to heat-seal the thermoplastic resin fibers to produce a four-axis assembly fabric in which warp yarns, weft yarns and oblique yarns are temporarily bonded to each other. Got.
In the obtained continuous fiber nonwoven fabric, the number of yarns arranged was 30 / 10cm in the warp direction, 29 / 10cm in the weft direction, and 22 / 10cm in the two oblique yarn directions, and the basis weight was It was 703 g / m ² .
[0026]
[Comparative Example 1]
A glass fiber roving of 570 tex as a reinforcing fiber (trade name: RS57PR481 manufactured by Nitto Boseki Co., Ltd.) was coated with nylon 6 as a thermoplastic resin to obtain a 840 tex resin-coated reinforced fiber yarn.
The resin-coated reinforcing fiber yarn is used as warps, wefts and skew yarns by the apparatus shown in FIGS. 1 and 2, and the weft yarns and the oblique yarns are sandwiched between every other warp yarns, and heated with the heat roller. By passing between the pressure rollers, the thermoplastic resin was thermally fused, and a four-axis assembly fabric in which warp yarns, weft yarns and oblique yarns were temporarily bonded to each other was produced, and a continuous fiber nonwoven fabric of Comparative Example 1 was obtained. .
In the obtained continuous fiber nonwoven fabric, the number of yarns arranged is 20 / 10cm in the warp direction, 19 / 10cm in the weft direction, and 14 / 10cm in the two oblique yarn directions, and the basis weight is It was 563 g / m ² .
[0027]
(2) Preparation of laminated plate Three continuous fiber nonwoven fabrics of Example 1 were stacked, and four continuous fiber nonwoven fabrics of Comparative Example 1 were stacked, each being heated and pressed at a temperature of 270 ° C. and a pressure of 10 kg / cm ² for 10 minutes. The laminated board of Example 1 and Comparative Example 1 was obtained by molding.
The thickness of the laminated board of Example 1 was 1.2 mm, and the thickness of the laminated board of Comparative Example 1 was 1.3 mm.
In addition, in the continuous fiber nonwoven fabric of the comparative example 1, since the rigidity of the resin-coated fiber yarn was too strong, the basis weight of the four-axis assembly fabric could not be made the same as that of the continuous fiber nonwoven fabric of Example 1. Therefore, in order to make the content of reinforcing fibers per unit area in the laminated board substantially equal between Example 1 and Comparative Example 1, the laminated board of Example 1 was prepared by laminating three continuous fiber nonwoven fabrics, and Comparative Example The laminate 1 was prepared by laminating four continuous fiber nonwoven fabrics.
[0028]
(3) Evaluation of mechanical properties of laminates The laminates of Example 1 and Comparative Example 1 were subjected to warp direction (0 ° direction), weft direction (90 ° direction), and oblique yarn direction (± 45 ° direction). Based on JIS K7055, bending strength and bending elastic modulus were measured.
The measurement results are shown in Table 1.
[0029]
[Table 1]

[0030]
【The invention's effect】
Since the composite fiber yarn in the present invention has a lower rigidity than the resin-coated reinforcing fiber yarn, the basis weight of the reinforcing fiber can be easily increased when a nonwoven fabric made of continuous fiber yarn is prepared. Further, in the continuous fiber nonwoven fabric of the present invention, the thermoplastic resin does not cover the reinforcing fiber yarn but forms the reinforcing fiber and the composite fiber yarn as the fiber, so that the needle punching can be easily performed. Therefore, the fiber reinforced thermoplastic resin molding material using the continuous fiber nonwoven fabric composed of this composite fiber yarn can obtain excellent mechanical properties, and it is not necessary to add a matrix resin in the molding process. Can be simplified.
[Brief description of the drawings]
FIG. 1 is a plan view of a continuous fiber nonwoven fabric manufacturing apparatus according to the present invention. FIG. 2 is a side view of a continuous fiber nonwoven fabric manufacturing apparatus according to the present invention.
DESCRIPTION OF SYMBOLS 1, 1 'Thread pin 2, 2' Pin arrangement 3 Conveyor 4, 9 Traverse guide 5, 10 Traverse tool 6, 11 Guide pipe 7, 12 Composite fiber yarn for weft and diagonal yarn 8, 13 Continuous fiber yarn Aggregate 14, 15 Composite fiber yarn 16 for warp Heat roller 17 Pressure roller 18 Continuous fiber nonwoven fabric in the form of a 4-axis assembly

Claims (3)

A first continuous fiber in which a plurality of continuous fiber yarns are arranged in parallel by disposing continuous fiber yarns composed of composite fiber yarns of glass fibers and thermoplastic resin fibers whose volume ratio of glass fibers is 40 to 60%. A first fiber yarn layer comprising a yarn group; a second fiber yarn layer comprising a second continuous fiber yarn group in which a plurality of the continuous fiber yarns obliquely intersecting the first continuous fiber yarn group; A continuous fiber nonwoven fabric comprising a third fiber yarn layer comprising a third continuous fiber yarn group in which a plurality of the continuous fiber yarns obliquely intersecting the first continuous fiber yarn group from the opposite direction to the second continuous fiber yarn group. Get
Next, a method for producing a sheet-like stampable sheet, in which one or a plurality of the continuous fiber nonwoven fabrics are stacked and heated and pressed. In the continuous fiber nonwoven fabric, stampable of claim 1 comprising the first fourth filament layer, wherein the continuous fiber yarns perpendicular to the continuous fiber yarn group a fourth consecutive fiber yarn groups being more parallel Sheet manufacturing method. In the continuous fiber nonwoven fabric, the composite fiber yarns are temporarily bonded or entangled to maintain the form of the continuous fiber nonwoven fabric,
Then, the manufacturing method of the stampable sheet of Claim 1 or Claim 2 which heats and press-molds the said continuous fiber nonwoven fabric 1 sheet or several sheets .

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