KR960016594B1 - Method for manufacturing thermoplastic composite - Google Patents

Abstract

laminating a polypropylene sheet(A) of a high fluidity, in which ethylene propylene diene terpolymer is dispersed, a non-oriented glass fibrous mat(B), unidirectionally oriented glass fibrous mat(C) woven by a glass long staple as a warp yarn and a polypropylene fiber as a filling yarn, a polypropylene resin(D) melted by an extruder, according to the order of A/B/C/D/C/B/A; laminating the non-oriented glass fibrous mat(B) and the mat(C) woven by a glass long staple as a warp yarn and a polypropylene fiber as a filling yarn, which experience needle punching; heat melting and impregnating the laminate under atmosphere of more than melting temperature of the risin.

Description

Manufacturing Method of Thermoplastic Composite Prepreg

1 is a longitudinal sectional view showing the internal structure of the composite material prepreg of the present invention.

* Explanation of symbols for main parts of the drawings

A: Highly flexible polypropylene sheet in which ethylene-propylene-diene terpolymer is dispersed

B: Oriented Glass Fiber Mat

C: Matte made of glass long fiber and weft made of polypropylene fiber

D: Polypropylene resin melted by extruder

The present invention relates to a method for producing a plate-shaped thermoplastic composite prepreg, and more particularly, using a thermoplastic resin and a fibrous or mat-like glass fiber reinforcement, reusable, excellent mechanical strength, and heat resistance, The present invention relates to a method for producing a thermoplastic composite prepreg for producing a thermoplastic prepreg molded article having excellent fluidity and impregnation.

In general, fiber-reinforced thermoplastics have been developed in which short fiber-reinforced materials have been shortened. However, in the pellet manufacturing process and injection molding process, glass fibers are cut off to improve strength and stiffness, but impact resistance is not improved. The dimensional stability of the molded product is reduced.

In addition, although the thermosetting composite material is excellent in heat resistance, the productivity decrease and impact resistance by the curing time are problematic.

Plate-shaped fiber-reinforced thermoplastics are usually molded by stamping molding, which is used to heat plate-shaped prepregs above the melting temperature of the resin to make the plate-like material flowable, It is a method of manufacturing an arbitrary molded article by cooling the mold after injection molding by compression molding. The thermoplastic composite resin produced by such a method is light and has high mechanical strength, and is widely used for automobile parts, civil engineering, building formwork, and the like.

When molding a plate-like thermoplastic composite material, prepreg is injected into a mold to make a molded article, and a fibrous reinforcing material flows like a resin and is filled in the mold, so it is easy to flow. It is common to use a needle punched (NEEDLE PUNCHING) glass fiber mat.

However, when the resin and the non-oriented glass fiber mat are used, the mechanical properties are improved, but the surface properties are not good, and in particular, the moldings are forced in one direction and the mechanical properties are insufficient. In addition, the properties of the composite material are determined by the shape and content of the MATRIX and the glass fiber mat, the arrangement state, and the aggregation state. It is also important that the interfacial adhesion between the substrate and the glass fiber mat and the resin are impregnated with the glass fiber mat. This is because porosity in the composite material affects the deterioration of physical properties.

SIZING method suitable for U.S. Patent Nos. 3,664,909, 3,684,645, etc. for the production of plate-shaped composite material prepregs, and U.S. Patents 3,883,333, 3,664,909, etc. for the special processing of glass fiber mats. Although described in U.S. Patent No. 3,849,148 and the like, these methods can produce a composite having excellent impact resistance and rigidity, but the resin impregnability is not sufficient enough to have a poor fluidity during molding.

In order to improve the impregnation of the numerical value, a method of using high flow polypropylene is proposed in EP 211,249. However, the surface characteristics are poor and the molded part has a complicated shape when compressing the composite prepreg. In the case of having a shape such as a rib or a rib, there is a disadvantage in that the fluidity is deteriorated and the resin is filled but the reinforcing effect is decreased.

In addition, a method of using a glass fiber mat mechanically combining an unoriented glass fiber layer and a general-oriented glass fiber layer as a reinforcing material is described in European Patent No. 434,846, but impregnation of the resin becomes a problem when the glass fibers are arranged in one direction. Due to the long fiber oriented glass fiber mat, there is a drawback of poor fluidity.

Accordingly, it is an object of the present invention to provide a method for producing a thermoplastic composite prepreg with enhanced fluidity, impregnation, surface properties, mechanical properties, in particular mechanical properties in one direction.

In order to achieve the above object as well as another object easily expressed in the present invention, a highly flexible polypropylene sheet (A), which has improved impact resistance with ethylene propylene diene terpolymer, Unoriented glass fiber mat (B), inclined glass filament, weft yarns made of polypropylene fibers, that is, mats (C) with glass fibers arranged in one direction, and polypropylene resin (D) melted with an extruder. Prepreg is prepared by laminating in the order of B / C / D / C / B / A and heat-melting impregnating in the atmosphere above the melting temperature of the resin. Oriented glass fiber mat (B) and inclined glass filament and weft polypropylene mats with a fiber that is, one direction can be obtained a glass fiber is arranged mat (C) is a needle punching number of 20 to 70 times / cm ₂ with a needle having excellent various properties hameuroseo using the punched thermoplastic composite material prepreg The.

The present invention is described in more detail as follows.

Highly flexible polypropylene sheet (A) used in the present invention is a polypropylene having a melt index (MELT INDEX) in the range of 20 to 40 g / 10 min as measured by a load of 2.16 Kg at 230 ° C. in accordance with ASTM D 1238. The thickness of the sheet was adjusted so that the polypropylene resin used in the thermoplastic composite material by sheeting the resin was in the range of 50 to 70 wt% of the total weight.

In addition, polypropylene resin was modified with maleic acid, acrylic acid, etc. to improve adhesion to glass fiber, and increased needle punching number to improve fluidity, and also prevented glass fiber from being cut and lowered impact resistance. To this end, 1 to 20 wt% of the ethylene-propylene-diene terpolymer was mixed with the outermost polypropylene resin, more preferably 5 to 15 wt%, and used as a sheet.

As a reinforcing material, needle-punching was performed with an unoriented glass fiber mat (B) and a mat (C) with glass fibers arranged in one direction with a needle punching number of 20 to 70 times / cm ₂ , more preferably 30 to 50 times / cm ₂ . Was used. At this time, the glass fiber diameter of the non-oriented glass fiber mat (B) is 10-25 μm, more preferably 17-22 μm, and 100-500 glass fiber monofilaments, more preferably 300-400. An unoriented glass fiber mat surface-treated with an organosilane compound was used, and was in the range of 10 to 30 wt%, more preferably 15 to 20 wt%, based on the total weight of the composite material.

Mat (C) in which the glass fibers are arranged in one direction was used for the glass filament in the oblique direction, and the mat was prepared using polypropylene fibers in the weft direction. At this time, the glass filament was used in a monofilament having a diameter of 15 to 25 µm, more preferably 18 to 22 µm, and a collection speed of 300 to 400. The content of the glass fibers in the diagonal direction is preferably in the range of 10 to 30 wt%, more preferably 20 to 25 wt%, based on the total weight of the composite material.

When needle-punching an unoriented glass fiber mat (B) and a mat (C) in which glass fibers are arranged in one direction, they are entangled with each other and needle punched to cut glass fibers to produce short fibers. Depending on the size, shape, and number of needle punchings, needle punching is carried out so that the content of short glass fibers having a length of 3 cm or less is in the range of 40-80 wt%, more preferably in the range of 50 to 60 wt%, based on the total amount of unoriented glass fibers. .

The total content of glass fiber is 30 ~ 50wt% with respect to the thermoplastic composite prepreg, the content of non-oriented glass fiber mat (B) / slope is glass long fiber and weft is polypropylene fiber. Is adjusted to 40/60 to 60/40.

As described above, the prepreg of the thermoplastic composite material prepared according to the present invention has particularly excellent mechanical properties in the direction in which the glass fibers are arranged in one direction, and impregnation and flowability can be improved. It can be molded and used for bumper beams among automobile parts, and can be used for various fields such as building materials and mechanical parts.

The following examples and comparative examples further illustrate the invention but do not limit the scope of the invention. In Examples and Comparative Examples, the physical properties and properties of the prepared thermoplastic composite prepreg were evaluated by the following method.

1) Tensile Strength: ASTM D 638

2) Impact Strength: ASTM D 356

3) Heat Strain Strength: ASTM D 746

4) Impregnation of resin: Density measurement of composite prepreg with automatic density meter

5) Fluidity: The composite prepreg is cut into 10 × 50cm in width × length, preheated to 200 ° C for 20 minutes in an infrared oven (OVEN), and then 80bar in a mold with mold temperature of 70 ° C and width × length of 10 × 10cm. Compression molding at a pressure of Since the flowability of the composite material was calculated by the following equation.

Example 1

The outermost polypropylene sheet used was an ethylene-propylene-diene terpolymer obtained by dispersing 15 wt% of monomer in a polypropylene resin grafted with maleic acid as an initiator and having a thickness of 0.5 mm (A). A high flow polypropylene resin having a melt index of 22 g / 10 min and a maleic acid grafted between the fiber mats was extruded and laminated by melting the polypropylene (D) melted to a thickness of 2.5 mm using an extruder having a flat sheet die. In addition, an unoriented glass fiber mat (B) of continuous strand surface-treated with glycidyl ether trimethoxysilane and having a weight of 450 g / m ₂ per unit area was 20 wt% based on the total weight of the thermoplastic composite prepreg, and the diameter was 22 Laminate mat (C) woven with a glass fiber having a collecting speed of 350 μm, a polypropylene fiber with a weft yarn, and a glass fiber content of 22 wt% based on the total weight of the thermoplastic composite prepreg. -Highly flexible polypropylene sheet (A) / non-oriented glass fiber mat (B) / slanted fiber long fiber, weft mat (C) / polypropylene sheet woven from polypropylene fiber D) / Slant fiberglass, Weft fiberglass mat (C) / Oriented glass fiber mat (B) / Highly flexible polypropylene sheet in which ethylene-propylene-diene terpolymer is dispersed (A ). The non-oriented glass-fiber mat (B) and the slope was used to needle into the mat (C) is a 1cm ₂ needle be 30 times / cm ₂ per punched woven polypropylene fiber, glass fiber sheet living above, punching. In the lamination order described above, the resin was cooled by heating and pressing under a condition of 210 ° C. and 30 psi by a double belt press (DOUBLE BELT PRESS) to prepare a thermoplastic composite material prepreg of 3.7 mm.

Physical properties of the thermoplastic composite prepreg prepared by the above method are shown in Table 1 below.

Example 2

The sub-orientated glass fiber mat is 18wt% of the total weight of the thermoplastic composite material prepreg, the glass long fiber with a diameter of 22 µm and the collecting speed of 350 is inclined. Except for 24wt% of the total weight of the composite material prepreg was carried out in the same manner as in Example 1, the physical properties are shown in Table 1 below.

Example 3

The polypropylene sheet of the outermost layer was carried out in the same manner as in Example 1 except that the ethylene-propylene-diene terpolymer was dispersed in 10wt% of the polypropylene resin content, and the physical properties thereof were evaluated. It is shown in Table 1 below.

Example 4

The non-oriented glass fiber mat (B) and the warp yarn are the same as those in Example 1 except that the number of punchings of the mat (C) woven from polypropylene fiber was 50 times / cm ₂ . It was carried out, and the physical properties are shown in Table 1 below.

Comparative Example 1

The needle punching number is 10 times / cm by using only one direction of glass filaments having a diameter of 20 µm and a collecting speed of 350 in one direction instead of a mat (C) in which the glass filaments are inclined and the polypropylene fibers are woven with a weft. Except that ₂ was carried out in the same manner as in Example 1, the physical properties were evaluated and shown in the following Table 1.

Comparative Example 2

The non-oriented glass fiber mat is 20wt% of the total weight of the thermoplastic composite material prepreg, the glass long fiber with a diameter of 13 µm and the focal speed of 350 is inclined, and the polypropylene fiber is woven with a weft yarn. times / cm to ₂ was and is the same manner as that conducted in example 1 except that the content of the glass fibers to 22wt% for the total weight of the thermoplastic composite material prepreg, to evaluate its physical properties are indicated in Table 1 .

Comparative Example 3

The polypropylene sheet of the outermost layer was carried out in the same manner as in Example 1 except that the ethylene-propylene-diene terpolymer was not dispersed, and the physical properties thereof were shown in Table 1 below.

TABLE 1

Claims (5)

Highly flexible polypropylene sheet (A), non-oriented glass fiber mat (B) in which ethylene-propylene-diene terpolymer is dispersed, inclined glass fiber and weft yarn are woven from polypropylene fiber Is laminated in order of A / B / C / D / C / B / A with the mat (C) and the polypropylene resin (D) melted by an extruder, but the unoriented glass fiber mat (B) and the inclined glass filament The manufacturing method of the thermoplastic composite material prepreg characterized in that the weft weaving mat (C) made of polypropylene fibers is needle punched and laminated, and thermally melt-impregnated in an atmosphere at or above the melting temperature of the resin. The method of claim 1, wherein the polypropylene resin has a melt index of 20 to 40g / min, the polypropylene resin of the thermoplastic composite material prepreg, characterized in that the total content is 50 to 70wt% of the total weight of the thermoplastic composite material prepreg Manufacturing method. The method according to claim 1, wherein the content of the ethylene-propylene-diene terpolymer is 1 to 20 wt% with respect to the outermost polypropylene sheet. The method of claim 1, wherein the slope is a glass fiber, the weft yarn is a mat woven from polypropylene fiber, the diameter of the glass fiber is 15 to 25㎛, the focusing speed is used to focus to 300 to 400 nofilament Method for producing a thermoplastic composite prepreg, characterized in that. According to claim 1, the total content of the glass fiber is 30 to 50wt% with respect to the thermoplastic composite prepreg, the non-oriented glass fiber mat (B), the inclined glass filament, the weft yarn mat woven from polypropylene fiber ( C) and the content ratio is 40/60 to 60/40 and the needle punching number is 20 to 70 times / cm ₂ method for producing a thermoplastic composite material prepreg.