JP2935893B2 - Long fiber-containing resin composition and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fiber-reinforced resin composition of a polyolefin-based resin and a method for producing the same, and particularly relates to a resin composition having high impact resistance, and It can be used as a component material in the fields of automobiles, building materials and industrial materials that require high mechanical strength and high elastic modulus.

[Prior Art] Various resins are supplied from the synthetic resin industry, and their uses are being expanded to various fields by utilizing their unique properties. As a general property of synthetic resins, it is well known that they are lighter than metals and the like, but lack strength. Therefore, as a remedy, fibers such as glass fibers and carbon fibers are kneaded to improve the strength, and the field of use is further expanded.

As for fiber-reinforced plastics, thermosetting plastics-glass fibers were first developed and used in various fields, but thermoplastic resin-fiber-based resin compositions have also been developed (US Pat. No. 3,993,726). , JP-B 63-376
No. 94).

Conventionally, glass fiber is mainly used as a reinforcing fiber of fiber reinforced plastics, but glass fiber reinforced plastics have remarkably improved mechanical strength such as rigidity and elastic modulus, but impact strength is not significantly improved. However, there remains a problem in use in fields where impact resistance is required.

On the other hand, among thermoplastics, polyolefin-based resin lacks heat resistance, but has appropriate mechanical properties, is excellent in workability, is lightweight, and is particularly advantageous at low cost. have.

Such polyolefin-based resins are used for various purposes. In some cases, more flexibility is required, and in other cases, rigidity is required.

Polyolefin-based resins as materials for fields requiring mass production, such as automobiles and building materials, generally have low rigidity as they are, and have taken measures such as reinforcement with fillers and glass fibers to meet this demand. Although the fiber reinforced polyolefin has a remarkable improvement in rigidity and elastic modulus, the improvement in impact resistance is still insufficient as in other fiber reinforced plastics.

[Problems to be Solved by the Invention] The present invention relates to a polyolefin-based resin which has significantly improved impact resistance without deteriorating properties such as high rigidity, high elastic modulus and high tensile strength which are characteristics of fiber reinforced plastics. The aim is to develop compositions and methods for their production.

[Means for Solving the Problems] The present invention provides: [1] a polyolefin, an organic fiber (a) having a fiber diameter of 10 to 300 μm, and an inorganic fiber (b);
/ (B) is in the range of 0.1 to 1.9, and is manufactured by the pultrusion method so that the total amount of (a) and (b) accounts for 10 to 60% by weight of the total weight. [2] The long fiber-containing resin composition according to [1], wherein the polyolefin contains 0.1 to 10% by weight of an unsaturated carboxylic acid graft-modified polypropylene, [3] the polyolefin is polypropylene The organic fiber (a) is a polyethylene terephthalate fiber, and the inorganic fiber is a glass fiber; the long fiber-containing resin composition according to the above [1] and [2]; [4] an organic fiber having a fiber diameter of 10 to 300 μm ( a) and the inorganic fiber (b), wherein the weight ratio (a) / (b) is in the range of 0.1 to 1.9, and the ratio of the total weight of (a) and (b) to the total weight is 10 to 60% by weight. % Together with the polyolefin resin A method for producing a long-fiber-containing resin composition characterized by being extruded by a extrusion method, and [5] the above-mentioned [4], wherein the organic fiber is polyethylene terephthalate fiber, the inorganic fiber is glass fiber, and the polyolefin is polypropylene resin. The above object has been achieved by developing a method for producing a long fiber-containing resin composition according to the present invention.

In the present invention, the polyolefin refers to a hard polyolefin such as polypropylene, high-density polyethylene, and linear low-density polyethylene.

The polypropylene may be a propylene homopolymer, a propylene-ethylene random copolymer in which a small amount of ethylene is copolymerized, a copolymer obtained by block copolymerizing propylene and ethylene, or a mixture thereof.

The polypropylene preferably has an MFR measured under JIS K 7210 Table 1 condition 14 of 35 to 200 g / 10 min, particularly 35 to 150 g / 1.
Those within the range of 0 minutes are preferred for handling.

Polypropylene having an MFR of less than 35 g / 10 minutes is inferior in moldability, and if the MFR exceeds 200 g / 10 minutes, the moldability is good, but the mechanical properties of the obtained composition (particularly impact resistance) Tend to be inferior.

In the case of a random copolymer, the copolymerization ratio of ethylene is at most 10% by weight, preferably 6% by weight or less. As the ethylene copolymerization ratio increases, the flexural modulus of the resulting composition decreases.

The block copolymer is usually referred to as block PP, which is said to consist of a mixture of 90 to 70% homopolypropylene and 10 to 30% ethylene-propylene copolymer. The polymer may contain 30 to 60% of homopolypropylene.

As the high-density polyethylene and the linear low-density polyethylene, the melt flow index (measured under JIS K 7210 Table 1 condition 4) is 15 g / 10 min to 100 g / 10 min, especially 25 to 1
00g / 10 minutes is preferred.

The density is preferably 0.910 g / cm ³ or more. Density 0.91
If it is less than 0 g / cm ³ , there is a problem in heat resistance, and the temperature dependence of mechanical properties increases.

Polyolefin has low adhesion to reinforcing fibers,
The improvement can be achieved by including 0.1 to 10% by weight of a polyolefin modified with an unsaturated carboxylic acid.

Examples of unsaturated carboxylic acids include monobasic unsaturated carboxylic acids, dibasic unsaturated carboxylic acids, and derivatives thereof, for example, metal salts, amides, imides or anhydrides.

Of these, the monobasic unsaturated carboxylic acid is generally a carboxylic acid having at most 30 (preferably 25 or less) carbon atoms. In addition, the carbon number of the derivative is usually at most
There are 20 (preferably 15 or less). Further, the dibasic unsaturated carboxylic acid generally has at most 30 (preferably 25 or less) carbon atoms. The derivative usually has at most 30 (preferably 25 or less) carbon atoms.

These unsaturated carboxylic acids and representative examples thereof are disclosed in
No. 10,107, page 3, lower right column, line 8 to page 4, upper right column, line 12.

Among these unsaturated carboxylic acids and derivatives thereof, acrylic acid, methacrylic acid, maleic acid and anhydride thereof, 5-norbornene-2,3-dicarboxylic acid and anhydride thereof, and glycidyl methacrylate are preferred, and maleic anhydride is particularly preferred. Acids and 5-norbornenecarboxylic anhydrides are preferred.

Radical reaction initiators used in the production of graft-modified polyolefin resins include dicumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tertiary Organic peroxides such as tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane-3, lauroyl peroxide, and tert-butylperoxybenzoate Is mentioned.

In producing the modified polyolefin resin, the ratio of the unsaturated carboxylic acid and / or its derivative and the radical initiator to 100 parts by weight of the polyolefin resin is generally 0.01 to 5.0 parts by weight as a total amount, and is particularly preferably 0.02 to 5.0 parts by weight.
~ 2.0 parts by weight is preferred.

The ratio of the radical reaction initiator is usually 0.001 to 1.0
Parts by weight, preferably 0.005-1.0 parts by weight, especially
0.005 to 0.5 parts by weight are preferred. When the ratio of the radical reaction initiator is less than 0.001 part by weight, the effect of the graft modification is poorly exhibited, and not only a long time is required to complete the graft modification, but also unreacted substances are mixed. On the other hand, if it exceeds 1.0 part by weight, an excessive decomposition or a crosslinking reaction is caused, which is not preferable.

In the production, it can be produced by treating a polyolefin resin, an unsaturated carboxylic acid and / or a derivative thereof, and a radical initiator within the above-mentioned ratio. As described in JP-A-62-10170 and JP-A-61-132345, the polyolefin resin to be treated is kneaded in a molten state using an extruder, a Banhary mixer, a kneader, or the like. Methods, a solution method in which the polyolefin resin is dissolved in an appropriate solvent, a slurry method in which the polyolefin resin particles are suspended, or a so-called gas phase grafting method can be employed.

The treatment temperature is appropriately selected in consideration of the deterioration of the polyolefin resin, the decomposition of the unsaturated carboxylic acid or its derivative, the decomposition temperature of the radical initiator to be used, and the like. The method of kneading in the molten state is taken as an example. And usually 100 ~ 350 ℃
It is preferably from 150 to 300 ° C, and particularly preferably from 180 to 300 ° C.

Examples of the organic fibers (a) as the reinforcing fibers include polyester fibers such as thermoplastic polyethylene terephthalate, polyamide fibers such as nylon 6,6 and nylon 6, and aramid fibers. In particular, since the organic fiber (a) is used for improving impact resistance, which is a weak point of conventional fiber reinforced plastics, 20 to 2,000 monofilaments having an average diameter of 5 to 300 μm, preferably about 10 to 150 μm. It is preferable that about 30 to 300 rovings are preferably used in accordance with the size of the product.

Aramid is excellent in performance, but expensive, so usually polyethylene terephthalate fiber, nylon
It is good to use 6,6 fiber because it is balanced in performance including price.

As the reinforcing inorganic fiber (b), various inorganic fibers used in fiber reinforced plastics can be used. As a reinforcing inorganic fiber used for plastics, a commonly used glass fiber is most excellent in terms of a balance between price and performance. The thickness of the fiber is preferably 5 to 20 μm.

In the present invention, the organic fiber (a) and the inorganic fiber (b) are used in a weight ratio of (a) / (b) = 0.1 to 1.9.
And the total weight of the reinforcing fibers is 10 to 60% by weight based on the total weight of the resin composition.

When the weight ratio of (a) / (b) does not reach 0.1, the properties of the resin composition such as rigidity, elastic modulus, and tensile strength are improved as in the case of the inorganic fiber (b) alone, The improvement in impact resistance becomes insufficient.

Conversely, when the weight ratio of (a) / (b) exceeds 1.9, the impact resistance can be greatly improved, but the rigidity, elastic modulus,
The tensile strength and the like decrease, and fiber reinforcement becomes insufficient.

When the mixing ratio of the fiber to the resin composition is less than 10% by weight, the reinforcing effect becomes insufficient. The blending ratio is 60
When the content is more than% by weight, the properties as a synthetic resin are often impaired, and the processability is greatly reduced.

Hereinafter, one embodiment of the method for producing the resin composition of the present invention will be described with reference to the drawings.

In the present invention, a different fiber material reinforced resin composition is produced by using an apparatus as shown in FIG. 1 in order to impregnate a fiber with a high molecular weight resin.

The equipment is (1) an extruder, (2) a drawing die,
(3) A cooling tank, (4) is a take-off machine, and (5) is a strand cutter, which has a function of cutting a strand to any length up to 30 mm.

The drawing die has a structure as shown in FIG.
Fiber inlets are (2a), (2b), (2c), (2d), (2
e), (2f), (2g), and (2h). There are several types. Since the temperature on the resin inflow side of the die is high, the fiber inlet (2a),
For (2b), (2c), and (2d), it is preferable to use inorganic fibers with low leakage at the resin interface, and to use organic fibers with relatively low heat resistance on the resin outlet side of the die. The distance from the inorganic fiber inlets (2a), (2b), (2c) and (2d) to the die discharge is preferably the ratio of the diameter d of the die to the passing length l, l / d of 100 or more. The l / d ratio is preferably between 30 and less than 100.

Resin extrusion temperature from 190 ° C to 250 for polyethylene
℃, about 200 ℃ to 250 ℃ for polypropylene is good,
It is desirable to seal the entire extruder with an inert gas because it is easily decomposed.

[Operation] In the present invention, an inexpensive resin composition was developed with the aim of improving the impact resistance of fiber reinforced plastics.

First, the reinforcing effect of the conventional inorganic fiber is almost satisfactory except for the impact resistance. Without lowering this performance,
It was recognized that this improvement was possible by blending organic fibers to improve impact resistance.However, when kneading reinforcing fibers, polyamide, polyester, etc., which are high-performance thermoplastic resins, were mixed in a matrix. When used as a resin, the organic fibers of the reinforcing fibers were melted or the orientation was disturbed, and the reinforcing performance was significantly reduced.

On the other hand, polypropylene, high-density polyethylene, and the like have a low melting point and a low processing temperature, and can avoid a decrease in the performance of the organic fiber for reinforcing them. Fortunately, polyolefins are inexpensive and the resulting resin compositions are inexpensive, and the present invention has been selected based on the balance between workability and reinforcing properties.

In the method of the present invention, since the resin composition is produced by the pultrusion method, the organic fibers and the inorganic fibers are not kneaded in an extruder. Therefore, unlike the conventional method of manufacturing a resin composition using an extruder or a Banbury mixer, the fibers are not cut in advance, and the cut fibers are vigorously kneaded with the resin in an extruder or a Banbury mixer. Since there is no fiber is not cut or rounded, it becomes a resin composition containing long fibers cut with a cutter,
Impact resistance can be greatly improved without deteriorating properties such as high rigidity, high elastic modulus and high tensile strength.

[Example] (Example 1) A roving of 50 µ twisted glass fiber having a fiber diameter of 10 µm and a roving of polyethylene terephthalate having a fibrous diameter of 20 µm and 50 twist were performed by the same number ｛(a) / ( b)
Was used as a matrix resin, and was extruded by a pultrusion and cut into a length of 25 mm to obtain pellets.

According to JIS K 7113, a presson and a dumbbell were punched out and subjected to a bending test.
It was Kg / cm ² .

When this is reheated and compression molded with a press, 60,000Kg / c
It became m ^2.

A drop weight test with a head of 130 mm in length and a curvature of 6.35 mm from the tip of the molded product was measured for breaking strength using a test piece 130 mm in width and 3 mm in thickness.The energy at the position was 340 kg / cm ₂ . It showed high impact properties.

(Examples 2 to 6) In Examples, as shown in Table 1, the proportions of polyethylene terephthalate roving and glass fiber roving (both used the same as in Example 1) were changed to change the ratio (a) / ( After adjusting b), molding was performed using another resin material. As a result, high creep performance and impact resistance were exhibited as in Example 1.

The roving of the organic fiber (a) in Example 6 was a polyamide 66 fiber diameter of 20 μm and 50 strands.

(Comparative Examples 1-2) In Example 1, a polypropylene having a melt flow rate of 60 g / 10 min was used, and the ratio of (a) / (b) was 0.09.
When a test piece was prepared from the same molded body at 2.0 and the fracture energy was measured, the impact strength was low.

The impact strength was 100 kg · cm and 180 kg · cm, both of which were lower than those in Example 1.

[Effects of the Invention] The present invention uses an inexpensive polyolefin as a matrix resin, and comprises an organic fiber (a) and an inorganic fiber (b).
The present invention has succeeded in the development of a resin composition having high rigidity, high mechanical strength, and high elastic modulus by adding a reinforcing long fiber consisting of, and further imparting higher impact resistance to this property.

When this resin composition is manufactured by the pultrusion method, it is also possible to make a long extruded material such as a long extruded material contain a long fiber having the same length as the extruded material by selecting a shape of a sizer. Also, when producing pellets, it is easy to incorporate long fibers by selecting the pellet length.

When the resin composition of the present invention contains 10 to 60% by weight of a specific proportion of the reinforcing filaments of the organic fibers (a) and the inorganic fibers (b), it has particularly excellent resistance without deteriorating other mechanical properties. It exerts impact properties.

Further, since the manufacturing method is a pultrusion method, it is a method of exhibiting an excellent reinforcing effect without cutting the reinforcing fibers upon mixing the resin and the fibers.

[Brief description of the drawings]

FIG. 1 shows an example of a pultrusion apparatus for producing the resin composition containing long fibers according to the present invention. FIG. 2 is an example of a cross-sectional view of a drawing die portion in the device. 1. Extruder, 2. Drawing die 3. Cooling tank, 4. Pulling machine 5. Strand cutter 6. Roving feeding device

Claims (5)

(57) [Claims] 1. A fiber comprising a polyolefin, an organic fiber (a) having a fiber diameter of 10 to 300 μm, and an inorganic fiber (b), wherein the weight ratio of the fiber (a) / (b) is in the range of 0.1 to 1.9, A long-fiber-containing resin composition produced by a pultrusion method so that the total amount of (a) and (b) accounts for 10 to 60% by weight of the total weight. 2. The long fiber-containing resin composition according to claim 1, wherein the polyolefin contains 0.1 to 10% by weight of an unsaturated carboxylic acid graft-modified polypropylene. 3. The polyolefin is polypropylene,
3. The long fiber-containing resin composition according to claim 1, wherein the organic fiber (a) is a polyethylene terephthalate fiber and the inorganic fiber is a glass fiber. 4. An organic fiber (a) having a fiber diameter of 10 to 300 μm and an inorganic fiber (b) having a weight ratio (a) / (b) of 0.1 to 1.9.
Characterized in that it is extruded together with a polyolefin resin by a pultrusion method so that the ratio of the total amount of (a) and (b) to the total weight is 10 to 60% by weight. Manufacturing method. 5. The method according to claim 4, wherein the organic fibers are polyethylene terephthalate fibers, the inorganic fibers are glass fibers, and the polyolefin is a polypropylene resin.