JP2001234076A - Organic fiber resin composition and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded article of a fiber-reinforced resin having good mechanical properties. SOLUTION: The organic fiber resin composition contains 10-90 wt.% organic fibers impregnated with a thermoplastic resin having a melt viscosity of <=4 Pa.s and a molecular weight of >=1,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic fiber resin composition (masterbatch) using organic fibers as a reinforcing material and its use.

[0002]

2. Description of the Related Art In general, in order to improve rigidity, strength and resistance to bending fracture, a method of blending a resin with a reinforcing material such as a reinforcing fiber has been used. Organic fibers can provide molded products with better physical properties such as toughness and flexibility than inorganic fibers,
In addition, since it is a combination (thermoplastic resin and organic fiber) that is a material closer to general plastics, moldings that are easy to mold and can be recycled are obtained. However, since the specific gravity of the organic fiber is light and bulky, unlike the inorganic fiber, kneading of the resin is difficult, and various kneading methods have been studied.

[0003]

Problems such as generation of free fibers, poor kneading with a resin, and a decrease in the resin reinforcing ability due to breakage of an organic fiber, etc. are caused by an organic fiber-coated resin composition in which an organic fiber is previously coated with a resin. Can be almost solved by using. However, in the case where the fiber bundle is simply covered with resin as in this method, an air layer exists between the fibers. Immediately after that, there were problems such as poor surface appearance such as surface roughening caused by the escape of air bubbles, and inability to obtain good mechanical properties. This is a problem unique to an organic fiber material having high flexibility, which does not occur with inorganic fibers. Therefore, development for obtaining a practically usable new organic fiber resin molded product has been desired.

[0004]

That is, the first aspect of the present invention is as follows.
Of the invention has a melt viscosity of 4 Pa · s or less and a molecular weight of 1000
Organic fiber 10 impregnated with thermoplastic resin (A) as described above
It is an organic fiber resin composition containing about 90% by weight.

A second invention is the organic fiber resin composition according to the first invention, wherein the thermoplastic resin (A) is a polymerized fatty acid-based copolymer polyamide resin.

In a third aspect, an organic fiber is selected from the group consisting of polyester fiber, nylon fiber, acrylic fiber, aramid fiber, regenerated cellulose fiber, cotton fiber, and hemp fiber.
Or the organic fiber resin composition according to the first or second invention, which is at least two kinds.

A fourth invention is a molded article comprising the organic fiber resin composition according to any one of the first to third inventions and a thermoplastic resin (B).

A fifth invention is the molded article according to the fourth invention, wherein the thermoplastic resin (B) is a polyolefin resin.

In a sixth aspect of the present invention, the melting point or softening point of the thermoplastic resin (B) is higher than the melting point or softening point of the thermoplastic resin (A). This is a method for manufacturing a molded article.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
Examples of the organic fibers used in the present invention include synthetic fibers such as polyester fibers, nylon fibers, acrylic fibers, and aramid fibers, chemical fibers such as regenerated cellulose fibers, and natural fibers such as cotton and hemp. One kind,
Alternatively, two or more kinds can be used.

The fiber diameter of the organic fibers is preferably 4 to 20 μm. If it is less than 4 μm, the bulk becomes bulky and the shearing force in the molten resin becomes weak. If it exceeds 20 μm, the surface of the molded product is not smooth, which is not preferable.

[0012] After impregnating the thermoplastic resin (A) with the organic fiber as a unit of 5000 to 15000 bundles,
An organic fiber resin composition is obtained by pellet molding. Since the bundle of the organic fibers affects the thickness of the organic fiber resin composition, outside the above range, the diameter of the organic fiber resin composition is too small or too large to be used.

Examples of the method of impregnating the organic fibers with the thermoplastic resin (A) include, for example, a known method of impregnating the organic fibers with the thermoplastic resin (A) whose viscosity has been reduced by heating. By this impregnation step, the space between the fibers constituting the organic fiber bundle is filled with the thermoplastic resin (A), and the organic fibers are surely integrated and held without being separated, so that the subsequent handling property is improved. It becomes better and workability is improved.

Preferably, the organic fibers are opened before impregnation. The impregnation of the resin is performed smoothly in a short time by opening, and even if the molding conditions slightly change, high impregnation is maintained,
Since the resin is impregnated so as to uniformly disperse the fibers and surround each fiber, the space existing between the fibers is reduced, the number of the spaces is reduced, and a good impregnation state is obtained.

The non-twisted organic fibers are easier to spread, so that the organic fibers are more likely to be impregnated with the thermoplastic resin (A). However, twisted ones can also be used. Further, the organic fibers may be twisted at the outlet of the die of the impregnation device after the impregnation. By winding and twisting fibers that have been loosened or cut short in the die, they prevent clogging of the orifice caused by these, and the impregnated resin oozes out of the bundle of fibers and Has an effect of protecting the organic fibers.

The organic fiber used in the present invention is preferably processed with the thermoplastic resin (A) or the thermoplastic resin (B) at a temperature at which the stretchability is not lost.

The thermoplastic resin (A) used in the present invention
Is a resin having a melt viscosity of 4 Pa · s or less and a molecular weight of 1000 or more. When the melt viscosity exceeds 4 Pa · s, impregnation becomes difficult, and when MN is less than 1,000, pellet molding becomes difficult, which is not preferable. The melt viscosity in the present invention is measured at a test temperature of 200 ° C. in accordance with JIS K6862, and the molecular weight is defined as HP
It is a number average molecular weight (hereinafter, referred to as MN) measured by LC.

The organic fiber strand impregnated with the thermoplastic resin (A) is thereafter cut by mechanical impact treatment and pelletized to obtain an organic fiber resin composition. This pellet molding step is indispensable for the quantitative supply of the organic fiber resin composition. With a resin having an MN of less than 1000, the resin cannot withstand the impact of the pellet molding, and can quickly maintain the pellet shape. Absent. The “pellet” in the present invention refers to a molding material granulated into a small sphere, a cylinder, a prism, or the like having a diameter or a side of about 2 mm to 5 mm.

Specific examples of the thermoplastic resin (A) include a polymerized fatty acid-based copolymer polyamide resin, which has 2 carbon atoms.
A polymerized fatty acid of 0 to 48, a short-chain dibasic acid and a diamine,
(Polymerized fatty acid / short-chain dibasic acid) weight ratio of 0.25 to 0.25
5.2, and a mixture obtained by mixing and polycondensing such that all amino groups are substantially equivalent to all carboxyl groups. Commercial products include Tomide 1310 and Tomide 1
350 (manufactured by Fuji Chemical Industry Co., Ltd.) and the like.

Examples of the polymerized fatty acid having 20 to 48 carbon atoms include unsaturated fatty acids, for example, polymerized fatty acids obtained by polymerizing monobasic fatty acids having at least one double bond or triple bond having 10 to 24 carbon atoms. Is used. Specific examples include dimers such as oleic acid, linoleic acid and erucic acid. Commercially available polymerized fatty acids usually contain a dimerized fatty acid as a main component, and further contain a raw material fatty acid and a trimerized fatty acid. The dimerized fatty acid content is 70% or more, preferably 95% or more. Desirably, the degree of unsaturation is reduced by hydrogenation. Examples of the Buriball 1009, the Buriball 1004 (all manufactured by Unichema), and the Enball 10
Commercially available products such as No. 10 (manufactured by Henkel) are exemplified.

Examples of the short-chain dibasic acid include azelaic acid, sebacic acid and a mixture of both.

As the diamine, a diamine having 2 to 20 carbon atoms is preferable.
4-aminobutane, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, bis- (4,4'-aminocyclohexyl)
Diamines such as methane and meta-xylylenediamine are exemplified.

In the production of the organic fiber resin composition, if necessary, as long as the function of the organic fiber resin composition is not impaired,
In addition to the above components, additives such as heat stabilizers, weathering agents, lubricants, slip agents, flame retardants, nucleating agents, pigments, dyes and the like may be blended.

The organic fiber resin composition of the present invention is a master batch. The masterbatch contains a high concentration of organic fibers and dilutes the organic fiber content to a desired concentration with a thermoplastic resin (B) which is a diluting resin (uncolored thermoplastic resin) at the time of molding a molded article. Refers to an organic fiber resin composition to be a molded article.

The mixing ratio of the thermoplastic resin (A) in the master batch is desirably 10 to 20% by weight. When the amount is less than these ranges, the amount is not sufficient to be impregnated into the organic fibers, so that the organic fibers are not bundled into one bundle, and the organic fiber resin composition may not be molded. In addition, even if an amount exceeding these ranges is used for impregnation, not only the effect corresponding to the amount cannot be expected, but also the amount of organic fibers in the masterbatch is relatively reduced, and the effect of enhancing the physical properties of the molded article is reduced. May be reduced.

In order to suppress mechanical damage to the organic fibers during production, the masterbatch and the thermoplastic resin (B) are not melt-kneaded in advance, but are directly injected into an injection molding machine or an extrusion molding machine when processing a molded product. Since the manufacturing process of mixing for the first time in the machine is reduced as much as possible, it is necessary that the organic fibers be rapidly and uniformly dispersed in the thermoplastic resin (B) in the molding machine. Therefore, the melting point or softening point of the thermoplastic resin (A) impregnated in the organic fiber bundle is preferably equal to or lower than the melting point or softening point of the thermoplastic resin (B).

The thermoplastic resin (B) used in the present invention
Is compatible with the thermoplastic resin (A). Examples of the olefin resin include polyethylene, polypropylene, ethylene-propylene copolymer, acid-modified olefin resin, and the like. Examples of the styrene resin include impact-resistant polystyrene, ABS resin, styrene-butadiene copolymer, and the like. Resins, PET resins, polyamide resins, polyacetal resins, and the like. These can be used alone or in combination of two or more.

The compounding ratio of the organic fiber in the molded product varies depending on the intended use of the molded product.
% By weight, especially 20-40% by weight. 10% by weight
If it is less than 90%, the mechanical properties of the molded product cannot be obtained and 90% by weight.
Exceeding the range is not preferable because defects such as warpage occur in the molded product.

The proportion of the thermoplastic resin (B) in the molded article is preferably 50 to 80% by weight, more preferably 70 to 80% by weight. If the amount is less than 50% by weight, the fluidity of the resin deteriorates, resulting in molding failure.

In the production of the organic fiber reinforced resin molded article of the present invention, a heat stabilizer, a weathering agent, a lubricant, a slip agent, a flame retardant, a nucleating agent, and the like may be used, as long as the function of the molded article is not impaired. Additives such as pigments and dyes may be blended.

[0031]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, mechanical property test (elongation) of plate molded products
Was performed in accordance with ASTM D-638, and the results are shown in Table 1. (Example 1) Heat-melted polymerized fatty acid-based polyamide resin (melt viscosity 3.8 Pa · s, MN 3000, softening point 15
4 ° C) 60% by weight of 40% by weight impregnated polyester fiber (16 μm in diameter, 7000 fiber bundles) is made into a strand and cut with a pelletizer to obtain a pellet-shaped organic fiber resin composition having a length of 7mm. Was. 50% by weight of the above organic fiber resin composition and polypropylene (melting point: 160 ° C.)
50% by weight, and subjected to plate molding using a Toshiba IS100F1 type injection molding machine at an injection temperature of 190 ° C. and a mold temperature of 40 ° C.

(Comparative Example 1) Only the same polypropylene as in Example 1 was molded into a plate under the same conditions as in Example 1 without blending the organic fiber resin composition.

(Comparative Example 2) Polyester fiber (fiber diameter 1
6 μm, length 7.5 mm) 60% by weight and polyethylene 4
0% by weight, and charged into a Henschel mixer 150L (manufactured by Mitsui Miike Kakoki Co., Ltd.).
After stirring at a high speed set at 0 ° C., the stirring was changed to a low speed when the polyethylene was melted, and the melt-mixed resin composition was replaced with a cooling mixer and sufficiently cooled.
The mixture was pulverized with a pulverizer to obtain a pellet-shaped organic fiber resin composition. Using the above organic fiber resin composition, plate molding was performed in the same manner as in Example 1.

Comparative Example 3 Polyester Fiber (Fiber Diameter 1
After coating 60% by weight (6 μm, 7000 fiber bundles) with 40% by weight of the same polypropylene as in Example 1, it was made into a strand and cut with a pelletizer to obtain a 7 mm long pellet-shaped organic fiber resin composition. . Using the above organic fiber resin composition, plate molding was performed in the same manner as in Example 1.

(Comparative Example 4) Heat-melted polymerized fatty acid-based polyamide resin (melt viscosity: 0.63 Pa · s, MN98)
0) 60% by weight of a polyester fiber impregnated with 40% by weight (fiber diameter 16 μm, 7000 fiber bundles) was made into a strand and cut with a pelletizer, but the shape was lost and pellet molding was not possible. The subsequent experiments were not performed because the quantitativeness of the masterbatch to be compounded during the production of the molded article could not be obtained.

(Comparative Example 5) Polyamide resin (nylon 1
2) 40% by weight of polyester fiber (fiber diameter 16 μm,
An attempt was made to impregnate 60% by weight (7000 fiber bundles), but the impregnation could not be performed, and therefore no subsequent experiment was performed.

[0037]

[Table 1]

[0038]

The thermoplastic resin (A) used in the present invention
Is easy to be impregnated with organic fibers and good in pellet molding. Therefore, (1) bulky organic fibers are compacted to increase the specific gravity and organic fiber content per unit volume, and (2) Filling the periphery of the organic fiber with the thermoplastic resin (A) plays a role of protecting the organic fiber until the production of a molded article. (3) Molding with good mechanical properties of the organic fiber due to good quantitative supply property. Products can be provided.

Continued on the front page F-term (reference) 4F072 AA02 AB02 AB03 AB04 AB05 AB06 AC08 AD04 AD05 AG05 AH05 AH23 AK15 AL01 4J002 AA01W AB01X BB00W BB03W BB12W BB15W BB21W BC04W BC05W BG00X BN15W CB00W CF00 CL00X CF00 CL07X00

Claims (6)

[Claims] 1. A melt viscosity of 4 Pa · s or less and a molecular weight of 100
Organic fiber 1 impregnated with a thermoplastic resin (A) of 0 or more
An organic fiber resin composition containing 0 to 90% by weight. 2. The organic fiber resin composition according to claim 1, wherein the thermoplastic resin (A) is a polymerized fatty acid copolymer polyamide resin. 3. The organic fiber according to claim 1, wherein the organic fiber is at least one selected from polyester fibers, nylon fibers, acrylic fibers, aramid fibers, regenerated cellulose fibers, cotton fibers, and hemp fibers. Organic fiber resin composition. 4. A molded article comprising the organic fiber resin composition according to claim 1 and a thermoplastic resin (B). 5. The molded article according to claim 4, wherein the thermoplastic resin (B) is a polyolefin resin. 6. The method according to claim 4, wherein the melting point or softening point of the thermoplastic resin (B) is equal to or higher than the melting point or softening point of the thermoplastic resin (A).