KR20070001944A - Fiber-reinforced polyolefin resin composition and molding thereof - Google Patents

Abstract

A fiber-reinforced polyolefin resin composition comprising the following components: (A) 99 to 80 vol.% of polyolefin resin whose relaxation time at angular frequency omega =1(rad/sec) calculated from storage modulus G' and loss modulus G'' measured by means of a cone & plate rheometer, lambda=G'(G'' x omega), is 0.2 (sec) or less; and (B) 1 to 20 vol.% of reinforcing fiber. ® KIPO & WIPO 2007

Description

FIBER-REINFORCED POLYOLEFIN RESIN COMPOSITION AND MOLDING THEREOF

The present invention relates to a fiber-reinforced polyolefin resin composition and molded articles thereof.

Conventionally, polypropylene is a molding material that is easy to be molded having excellent stiffness and heat resistance due to its high crystallinity, high tensile strength as well as desirable electrical properties and chemical stability based on resin structure, and is widely used in various fields. It is becoming.

However, the polypropylene has a drawback of poor dimensional stability due to its crystallinity, and in recent years, higher rigidity and heat resistance have been required for mechanical parts, structural materials, and applications exposed to high temperatures.

Therefore, in order to improve the rigidity, dimensional stability, and heat resistance of such polypropylene, it is attempted to blend glass fibers.

However, this glass fiber reinforced polypropylene has been considerably improved in rigidity and heat resistance, but has a drawback in that deformation such as warpage and warpage tends to occur.

In general, when the reinforcing fibers are blended with the polyolefin resin to improve the polyolefin resin composition or the molded article thereof, the rigidity of the original polyolefin resin composition or the molded article thereof can be improved with a relatively small amount of addition compared to other fillers. Improvement of characteristics, such as strength and heat resistance, can be aimed at. For this reason, a small amount of reinforcing fibers is often added for the development of a molded article that improves the lightness (low specific gravity) of the polyolefin resin and also improves rigidity, strength and heat resistance. In that case, since the curvature becomes large when the addition amount of reinforcing fiber is small, the method of reducing the curvature of the molded article when the fiber content rate in a resin composition is small is examined.

As a review of a resin composition or a molded article which reduces warpage, a specific range of composition comprising a crystalline propylene polymer, a specific low crystalline ethylene-propylene random copolymer, glass fiber, a carboxylic acid-modified polypropylene, and a specific inorganic filler is disclosed (patent See Document 1).

However, in this composition, when a specific low crystalline ethylene-propylene random copolymer is added, there exists a fault that the improvement effect of the rigidity and strength which are the original objectives of adding reinforcement fiber fall. In addition, this document does not disclose the warpage reduction method when the content of the reinforcing fiber is small.

Moreover, the glass fiber reinforced polypropylene composition (refer patent document 2) which mix | blended the specific amount of the mica which has a specific shape, the glass fiber reinforced polypropylene composition (refer patent document 3), etc. which mix | blended mica powder are also disclosed.

However, these compositions have problems such as increasing the specific gravity (heavy) by adding a large amount of filler of reinforcing fibers, deteriorating physical properties such as strength, and reducing heat resistance.

Moreover, the long fiber reinforced resin composition with a big melt index (MFR) is disclosed (refer patent document 4 and 5). In these documents, in the case of the fiber-reinforced resin composition having a large amount of fiber, the addition of the fiber lowers the MFR of the resin composition, thereby causing an increase in temperature and pressure in the production of the fiber-reinforced product, thereby increasing the high pressure of this manufacturing process. It is disclosed that this warping occurs. In addition, these documents do not disclose a warpage reduction method when the fiber content is small.

Patent Document 1: Japanese Patent Publication No. 1991-223356

Patent Document 2: Japanese Patent Application Laid-Open No. 1990-238038

Patent Document 3: Japanese Patent Application Laid-Open No. 1992-25541

Patent Document 4: Japanese Patent Application Laid-Open No. 1990-77459

Patent Document 5: Japanese Patent Application Laid-Open No. 1998-230517

This invention is made | formed in view of the said situation, and an object of this invention is to provide the fiber reinforced polyolefin resin composition and its molded article from which the molded article with small curvature is obtained even when there is little content of reinforcing fiber.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, it discovered that it is effective to control the melt-viscoelastic characteristic of the resin part of a fiber reinforced polyolefin resin composition, and completed this invention.

Disclosure of the Invention

According to this invention, the following fiber reinforced polyolefin resin compositions and molded articles are provided.

1. (A) Relaxation time at angular frequency ω = 1 (rad / sec) calculated from storage modulus (G ') and loss modulus (G ") measured with a cone and plate rheometer 99 to 80% by volume of polyolefin-based resin having a λ = G '÷ (G ″ × ω) of 0.2 (sec) or less, and

(B) 1 to 20% by volume of reinforcing fibers

Fiber reinforced polyolefin-based resin composition comprising a.

2. The fiber-reinforced polyolefin resin according to the above 1, wherein the weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polyolefin resin (A) is 90,000 to 300,000 and the Z average molecular weight (Mz) is 100,000 to 600,000. Resin composition.

3. The fiber-reinforced polyolefin resin composition according to the above 1 or 2, wherein the reinforcing fibers (B) are glass fibers having a fiber diameter of 3 to 30 µm.

4. The fiber-reinforced polyolefin resin composition according to the above 1 or 2, wherein the reinforcing fibers (B) are carbon fibers having a fiber diameter of 3 to 30 µm.

5. The fiber-reinforced polyolefin resin composition according to any one of the above 1 to 4, further comprising a polyolefin resin modified with 0.1 to 50 parts of an unsaturated carboxylic acid or a derivative thereof, based on 100 parts of the polyolefin resin (A).

6. Molded article formed by molding the fiber-reinforced polyolefin resin composition according to any one of 1 to 5.

7. The molded article according to 6 above, having vertical walls or ribs.

According to the present invention, it is possible to provide a fiber-reinforced polyolefin resin composition and a molded article thereof in which a molded article having a small warpage can be obtained even when the content of the reinforcing fiber is small.

In addition, by controlling the melt viscoelasticity of the resin portion as in the present invention, not only the fiber-reinforced resin composition having a low content of reinforcing fibers, but also a composition in which a molded article having a small warpage can be obtained in the case of a wide fiber content can be provided.

1 is a view of a molded article produced in the Examples and Comparative Examples.

2 is a developed view of molded articles produced in Examples and Comparative Examples.

The polyolefin resin (A) has a relaxation time λ = G 'when the angular frequency ω = 1 (rad / sec) calculated from the storage modulus (G') and the loss modulus (G ") measured by a cone and plate rheometer. ÷ (G "x ω), that is, G '÷ G" is 0.2 (sec) or less. This value is preferably 0.15 (sec) or less, more preferably 0.12 (sec) or less, still more preferably 0.10 (sec) or less If the relaxation time (lambda) exceeds 0.2 (sec), the curvature of a molded article will increase.

Hereinafter, the relaxation time λ will be described.

When an external force is applied to a material system that is in equilibrium and the external force is removed after reaching a new equilibrium state or normal state, the phenomenon that the system recovers to the initial equilibrium state by the internal movement of the system is called a relaxation phenomenon. The characteristic time constant that is the basis of time is called relaxation time. In the case of the molding process of the polymer, the molten polymer is flowed, at which time the molecular chain is stretched and aligned in the flow direction (this is referred to as "orientation"). However, when the flow ends and cooling starts, the stress applied to the molecules disappears, and each molecular chain starts to move and eventually goes in a random direction (this is called "relaxation of molecular chain").

This relaxation time [lambda] can be expressed as [lambda] = G '/ [omega] G "= G' / G" when the angular frequency [omega] = 10 [deg.] = 1 (rad / sec).

Where G 'is the storage modulus, the elastic properties of the polyolefin resin, and G "is the loss modulus, the viscous properties of the polyolefin resin. As apparent from this equation, the relaxation time (λ) is increased. In the case of (large), G 'is large, and many components exhibiting elastic properties in the polyolefin resin are increased. In addition, when the relaxation time (λ) is shortened (smaller), G' 'is large and polyolefin is used. It means that there are many components which show viscous property in system resin, ie, the molecular weight of resin is small and molecular weight distribution is narrow.

If the relaxation time? Is large, it is considered that the molecular chains oriented at the time of injection molding do not return to a random state at the time of solidification, but the skin layer thickness (skin layer fraction) becomes thick. When the skin layer becomes thick, the anisotropy of the shrinkage rate of the resin increases, and a direction in which the shrinkage rate is large occurs. In addition, it is thought that the orientation of the fiber itself changes in the skin layer due to the difference in relaxation time [lambda]. On the other hand, since the fiber oriented by flow suppresses shrinkage of resin, it is thought that the difference of the shrinkage rate in a direction and a part becomes large, and curvature and deformation worsen. Therefore, it is thought that when λ becomes small, the orientation of the fiber itself changes, and as a result, warpage is reduced. This effect is considered to be related to the fiber orientation being different in the inside and the surface of the molded article, and in the expanded article and the parallel flow section in the molded article having the vertical wall.

In addition, the phenomenon that this warpage and deformation deteriorate is remarkable when the volume content of the reinforcing fiber is small. This is considered to be because when the volume content is increased, the rigidity is increased to suppress warpage and deformation caused by shrinkage of the resin.

The adjustment method of relaxation time (lambda) has the following method.

(1) It decompose | disassembles with a peroxide etc. and changes molecular weight distribution (especially it is easy to obtain resin with small (lambda) by decomposing | disassembling at high magnification from a high molecular weight thing).

(2) A plurality of resins having different molecular weight distributions are mixed. (It is effective to make and combine a resin having a narrow molecular weight distribution by using a highly active catalyst or increasing the decomposition rate by using a large amount of peroxide.)

(3) Each polymerization condition of multistage polymerization is adjusted (however, industrially, there may be disadvantages in terms of cost).

(4) A polymerization catalyst is selected.

Content of polyolefin resin (A) in the composition of this invention is 99-80 volume%, Preferably it is 99-88 volume%, More preferably, it is 98.5-93 volume%. If the content exceeds 99% by volume, the amount of reinforcing fibers decreases, and the reinforcing effect does not appear. On the other hand, when it is less than 80 volume%, the difference of the curvature and deformation by a resin part becomes small.

As polyolefin resin (A) used for the composition of this invention, polyethylene resin (for example, low density polyethylene (LDPE), ethylene-alpha-olefin copolymer), polypropylene resin, etc. can be used. Preferably, it is polypropylene resin.

Polypropylene resins include propylene homopolymers, propylene-α-olefin random copolymers, propylene-α-olefin block copolymers, and the like.

The melt index (MFR) of the polyolefin-based resin (A) is usually 1 to 600 g / 10 minutes, preferably 10 to 200 g / 10 minutes, more preferably 20 to 140 g / 10 minutes, even more preferably 40 to 120 g /. 10 minutes.

If the MFR is less than 1 g / 10 min, the dispersibility of the reinforcing fibers in the molded body may be lowered, and the appearance defect of the molded body may be seen. If the MFR is greater than 600 g / 10 min, the impact strength may be lowered, which is not preferable.

90,000-300,000 are preferable, as for the weight average molecular weight (Mw) measured by the gel permeation chromatography (GPC) of polyolefin resin (A), 100,000-250,000 are more preferable, 150,000-200,000 are more preferable. If Mw is less than 90,000, the toughness of the resin may be lost. On the other hand, when Mw exceeds 300,000, the dispersibility of the reinforcing fiber in a molded object may fall.

The Z average molecular weight (Mz) measured by GPC of the polyolefin-based resin (A) is preferably 100,000 to 600,000, more preferably 150,000 to 500,000, even more preferably 200,000 to 400,000. If Mz is less than 100,000, impact strength may fall. On the other hand, when Mz is 600,000 or more, curvature tends to occur.

As for the component of molecular weight 1,000,000 or more measured by GPC of polyolefin resin (A), 2% or less is preferable. More preferably, it is 1.5% or less, More preferably, it is 1.2% or less. If it exceeds 2%, warpage is likely to occur.

As for ratio (Mz / Mw) of Z average molecular weight (Mz) and weight average molecular weight (Mw) of polyolefin resin (A), 1.2-3 are preferable. More preferably, it is 1.5-2.5, More preferably, it is 1.7-2.3. If it is less than 1.2, molding (plasticization) tends to become unstable, and if it is more than 3, warpage is likely to occur.

As for the crystallization temperature (Tc) measured with the differential scanning calorimeter (DSC) of polyolefin resin (A), 90-130 degreeC is preferable. More preferably, it is 105-120 degreeC. If it is less than 90 degreeC, rigidity will be inadequate, and if it exceeds 130 degreeC, curvature will arise easily.

Polyolefin resin (A) can be manufactured by the method as described in Unexamined-Japanese-Patent No. 193-32723, Unexamined-Japanese-Patent No. 1999-71431, Unexamined-Japanese-Patent No. 2002-249624, etc.

For example, the polypropylene resin can be produced by slurry polymerization, gas phase polymerization or liquid layer bulk polymerization of propylene or the like using a catalyst for polymerization. As a polymerization method for producing such a propylene polymer, either of batch polymerization and continuous polymerization can be employed. Can be used.

The molecular weight at the time of superposition | polymerization of polyolefin resin (A) can be adjusted with the amount of hydrogen, etc. as described in Unexamined-Japanese-Patent No. 2002-226510.

Polyolefin resin (A) can decompose | disassemble using the organic peroxide mentioned later and can adjust relaxation time ((lambda)). Decomposition is possible anywhere in kneading by in plant, extruder, pellet production, and the like.

Examples of the reinforcing fibers (B) include inorganic fibers such as glass fibers and carbon fibers, silicon fibers, silicon titanium, carbon fibers, boron fibers, metal fibers such as iron and titanium, aramid fibers, polyester fibers, polyamide fibers, and vinylon. Known ones such as organic synthetic fibers such as natural fibers, natural fibers such as silk, cotton and hemp can be widely used. These can be used individually or in combination of 2 or more types.

The fiber diameter of the reinforcing fibers (B) is preferably 3 to 30 µm, more preferably 4 to 20 µm. When the fiber diameter is too small, the fiber is likely to be damaged, so the productivity of the reinforced fiber bundle may be lowered. In addition, it is unpreferable because the number of fibers must be bundled during the continuous production of pellets, and the effort for connecting the fiber bundles is complicated and productivity is lowered. In addition, in the case where the pellet length is determined, when the fiber diameter is too large, the aspect ratio (fiber length / fiber diameter) of the fiber is lowered, which is not preferable because the reinforcing effect is not sufficiently exhibited.

The aspect ratio of the reinforcing fibers (B) is preferably 5 to 10,000. More preferably, it is 10-60,000, More preferably, it is 100-3,000. If the aspect ratio is less than 5, sufficient reinforcement reinforcement may not be obtained, and if it exceeds 10,000, molding may be difficult.

Reinforcing fibers (B) are disclosed in Japanese Patent Publication No. 1986-187137, Japanese Patent Publication No. 1986-219732, Japanese Patent Publication No. 1986-219734, Japanese Patent Publication No. 1995-291649, Japanese Patent Publication Reinforcing fibers of a release cross section (elliptical shape, eyebrow shape, flat) described in Japanese Patent Application Laid-Open No. 1995-10591 may be used. In particular, it is preferable that ratio (D2 / D1) of the long diameter D2 with respect to the short diameter D1 of a cross section is 1.3-10, and short diameter D1 is 3-30 micrometers, and D2 / D1 is 2-5. And short diameter (D1) is 4-20 micrometers is especially preferable.

The content of the reinforcing fiber (B) in the composition of the present invention is 1 to 20% by volume, more preferably 1 to 12% by volume, particularly preferably 1.5 to 7% by volume. If the reinforcing fiber (B) is less than 1% by volume, the reinforcing effect is insufficient, and it is difficult to uniformly disperse the fiber. On the other hand, when it exceeds 20 volume%, the influence on the curvature of a resin part becomes small.

The surface of the reinforcing fiber (B) can have a functional group by various surface treatment methods, such as an electrolytic treatment and a condensate treatment. It is preferable to use a convergence agent as surface treatment, and it is especially preferable to use the convergence agent containing a coupling agent. When the surface-treated reinforcing fiber (B) is used in this way, adhesiveness with polyolefin resin (A) is provided and the molded object which is excellent in strength and an external appearance is obtained.

As an example of a procedure agent, what contains the coupling agent as described in Unexamined-Japanese-Patent No. 2003-253563, for example is mentioned.

As a coupling agent, it can select suitably from the coupling agents conventionally known as what is called a silane coupling agent and a titanium coupling agent.

Examples of the silane compound include γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and β- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- Amino silanes and epoxy silanes, such as (2, 4- epoxycyclohexyl) ethoxy methoxysilane and (gamma)-(2-aminoethyl) aminopropyl trimethoxysilane, can be used. In particular, it is preferable to use an amino silane compound.

Moreover, it is also preferable to contain a resin emulsion as a convergence agent in order to facilitate handling other than a coupling agent.

As a resin emulsion contained in a convergence agent, a urethane type, an olefin type, an acryl type, a nylon type, butadiene type, an epoxy type, etc. can be used, It is preferable to use a urethane type or an olefin type among these. Herein, the urethane-based convergence agent usually contains a polyisocyanate obtained by the polyaddition reaction of a diisocyanate compound and a polyhydric alcohol in a proportion of 50% by weight or more, and may be oil modified, moisture curable, and Any one of two-liquid types, such as a one-pack type, such as a block type, a catalyst hardening type, and a polyol hardening type, can be used. The bonding series and the hydrane series (both manufactured by Dainippon Ink Chemical Co., Ltd.) are typical.

On the other hand, a modified polyolefin resin modified with an aqueous urethane, such as an unsaturated carboxylic acid or a derivative thereof, can be used as the olefinic procedure.

It is preferable that tensile strength (B) is 1,000 Mpa or more, and it is especially preferable that it is 3,000 Mpa or more. Moreover, 50 GPa or more is preferable and, as for tensile elasticity modulus, 200 GPa or more is especially preferable. If these characteristics are out of the said range, sufficient reinforcement reinforcement may not be obtained.

As the reinforcing fibers (B) used in the present invention, glass fibers and carbon fibers are preferable because of the reinforcing effect and the availability.

As glass fiber, glass, such as E glass (Electrical glass), C glass (Chemical glass), A glass (Akali glass), S glass (High strength glass), and alkali-resistant glass, was melt-spun and used as a filamentary fiber. have.

A continuous glass fiber bundle is used as a raw material for the long glass fiber, which is commercially available as glass roving. Usually, the average fiber diameter thereof is 3 to 30 µm, the number of filament focusing bodies is 400 to 10,000, and the texture count is 300 to 20,000 g / km. Preferably it is an average fiber diameter of 13-20 micrometers, and the number of focusing bodies is 1,000-6,000 pieces. More preferably, it is an average fiber diameter of 16-18 micrometers, and the number of focusing bodies 3,000-5,000 pieces.

Further, a plurality of fiber bundles may be bundled and used as in Japanese Patent Laid-Open No. 194-114830.

In addition, glass chopped strands may be used as the glass fibers. The length of this strand is usually 1 to 20 mm, and the diameter of the fiber is about 3 to 25 µm, preferably 8 to 14 µm.

The fiber length of the glass fiber in the resin composition is usually 0.05 to 60 mm, preferably 0.1 to 20 mm, and the fiber diameter is preferably 3 to 30 µm, more preferably 8 to 20 µm.

As the carbon fiber, various conventionally known carbon fibers can be used.

Specifically, carbon fiber, such as a polyacrylonitrile system, a rayon system, a pitch system, a polyvinyl alcohol system, the regenerated cellulose, and the pitch system manufactured from mesophase pitch, is mentioned.

Preferably the fiber diameter of the carbon fiber in a resin composition is 3-30 micrometers, More preferably, it is 4-10 micrometers. When the fiber diameter is too small, the fiber is likely to be damaged, so the productivity of the reinforced fiber bundle may be lowered. Moreover, it is unpreferable because a lot of fibers must be bundled at the time of continuous manufacture of a pellet, and labor becomes complicated and productivity falls. In addition, in the case where the pellet length is determined, when the fiber diameter is too large, the aspect ratio of the fiber is lowered, which is not preferable because the reinforcing effect may not be sufficiently exhibited.

The aspect ratio of the carbon fiber is preferably 5 to 6,000. If the aspect ratio is lowered, the strength may be lowered. If the aspect ratio is too large, the moldability may be lowered.

A continuous fiber bundle is used as a raw material of the carbon long fiber, which is commercially available as a filament. Usually its average fiber diameter is 3 to 30 mu m, and the number of filament focusing bodies is 500 to 24,000. Preferably, the average fiber diameter is 4 to 10 µm and the number of focusing bodies is 6,000 to 15,000.

In addition, a chopped strand can also be used as carbon fiber. The length of this strand is usually 1 to 20 mm, and the fiber diameter is about 3 to 30 µm, preferably 4 to 10 µm.

The fiber length of the carbon fibers in the resin composition is usually 0.05 to 200 mm, preferably 0.1 to 50 mm, more preferably 5 to 20 mm.

In addition, the average aspect ratio (fiber length / fiber diameter) is 5 to 6,000, preferably 10 to 3,000, more preferably 15 to 2,000.

It is preferable that the carbon fiber surface was surface-treated by oxidation etching, coating | covering, etc. As the oxidation etching treatment, air oxidation treatment, oxygen treatment, treatment with oxidizing gas, treatment with ozone, corona treatment, flame treatment, (atmospheric pressure) plasma treatment, aqueous solution of oxidizing liquid (nitric acid, alkali hypochlorite metal salt, potassium dichromate) Sulfuric acid, potassium permanganate and sulfuric acid) treatment. Examples of the coating method include carbon, silicon carbide, silicon dioxide, silicon, plasma monomers, ferrocene, iron trichloride, and the like.

Moreover, you may use convergent agents, such as a urethane type, an olefin type, an acryl type, butadiene type, and an epoxy type, as needed.

The composition of the present invention may further include a polyolefin resin (modified polyolefin resin) modified with an unsaturated carboxylic acid or a derivative thereof.

Modified polyolefin resin has functional groups, such as a carboxyl group and an anhydrous carboxylic acid group, in polyolefin resin. Examples of the polyolefin resin to be modified include the above-described polyethylene resin and polypropylene resin.

When using polypropylene resin or its mixture as polyolefin resin, it is preferable to use modified polypropylene resin as modified polyolefin resin.

On the other hand, the modified polypropylene resin includes a propylene homopolymer, a propylene propylene-α-olefin random copolymer, a propylene propylene-α-olefin block copolymer, and the like modified as the above-described polypropylene resin.

Graft modification and copolymerization can be used as a modification method of polyolefin resin.

Examples of the unsaturated carboxylic acid used for modification include acrylic acid, methacrylic acid, maleic acid, nazi acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, sorbic acid, mesaconic acid, angerica acid, and phthalic acid. Examples of the derivatives thereof include acid anhydrides, esters, amides, imides and metal salts. Examples thereof include maleic anhydride, itaconic anhydride, citraconic anhydride, nazi anhydride, phthalic anhydride, methyl acrylate, methyl methacrylate, Ethyl acrylate, butyl acrylate, monoethyl ester, acrylamide, maleic monoamide, maleimide, N-butyl maleimide, sodium acrylate, sodium methacrylate, and the like. Among these, unsaturated dicarboxylic acid and derivatives thereof are preferable, and maleic anhydride or phthalic anhydride is particularly suitable.

The crystallization temperature (Tc) of the modified polyolefin resin is usually 90 to 125 ° C, preferably 110 to 120 ° C. The intrinsic viscosity is usually 0.1 to 2.4 dl / g, preferably 0.2 to 1.6 dl / g.

The carboxylic acid addition amount of the modified polyolefin resin is preferably 0.1 to 14% by weight, more preferably 0.8 to 8% by weight. Acid addition amount is by measuring the IR spectrum of the resin is determined from the area of the 1,670cm ^-1 to 1,810cm ^-1 peak.

The modification of the polyolefin-based resin may be carried out in advance of the preparation of the resin composition, or may be performed in the melt kneading process during the preparation of the resin composition.

When performing beforehand before manufacture of a resin composition, when manufacturing fiber reinforced resin pellets, an appropriate amount of the acid-modified polyolefin resin is added to polyolefin resin. At this time, it is preferable to add 0.1 to 50 weight%, more preferably 1 to 25 weight% of polyolefin resin which has a reactive functional group.

In the melt kneading process, the polyolefin resin and the unsaturated carboxylic acid or derivatives thereof are kneaded in an extruder using an organic peroxide to modify the unsaturated carboxylic acid or derivatives thereof by graft copolymerization.

Examples of the organic peroxide include benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, dicumyl peroxide, t-butyl hydroperoxide, and α, α'-bis (t-butylperoxydiisopropyl). ) Benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di- t-butyl peroxide, cumene hydroperoxide, etc. are mentioned.

The composition of the present invention, in addition, various additives such as dispersants, lubricants, plasticizers, flame retardants, antioxidants (phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants), antistatic agents, light stabilizers, ultraviolet absorbers, Modification additives such as crystallization accelerators, effervescent agents, crosslinking agents, antibacterial agents, coloring agents such as pigments and dyes, carbon black, titanium oxide, bengalla, azo pigments, anthraquinone pigments, phthalocyanine, talc, calcium carbonate, Particulate fillers such as mica and clay, short-fiber fillers such as wollastonite, whiskers such as potassium titanate and the like can be added.

These additives may be added at the time of pellet manufacture and contained in a pellet, or may be added at the time of manufacturing a molded object from a pellet.

In the case of short fiber reinforced resin pellets, the fiber reinforced resin composition of the present invention can be manufactured by melt kneading some or all of the components in an extruder or the like, and in the case of long fiber reinforced resin pellets by a known method such as drawing method It can manufacture. Some of the components may be separately kneaded and then mixed (blended).

The long fiber-reinforced resin pellets have a more significant effect because the aspect ratio of the fibers in the composition is large and a composition having high strength is easily obtained.

The shape of the fiber reinforced resin pellets may be any of powder, flake, pellet, and columnar phases. Preferably it is columnar.

The pellet length of the long fiber reinforced resin pellets is usually 2 to 200 mm. If the length of the pellet is too short, the effect of improving the rigidity, heat resistance and impact strength is low, and the warpage deformation may be large. If the length of the pellet is too long, molding may be difficult. Preferably, the pellet length is 2 to 100 mm, more preferably 3 to 50 mm, particularly preferably 6 to 12 mm.

It is also preferred that the reinforcing fibers of approximately the same length, with a fiber length of 2 to 200 mm, are side by side substantially parallel to each other.

Long-fiber reinforced resin pellets can be easily obtained by sending a roving of thousands of reinforced fibers to an impregnation die, uniformly impregnating the molten polyolefin resin between the filaments, and then cutting them to the required length (2 to 200 mm). have.

For example, while supplying molten resin from an extruder in the impregnation die provided in the tip of an extruder, passing a continuous glass fiber bundle, impregnating this glass fiber bundle with molten resin, drawing it out through a nozzle, and length of 2-50 mm The method of pelletizing is taken. Moreover, the method of carrying out dry blending of polyolefin resin, an unsaturated carboxylic acid or its anhydride, an organic peroxide, etc., into the hopper of an extruder, and also supplying while modifying simultaneously is also possible.

There is no restriction | limiting in particular as a method for impregnation, The method of passing a roving through the resin powder fluidized bed, and heating it beyond the melting point of resin (Unexamined-Japanese-Patent No. 1971-4545) of a reinforcing fiber using a crosshead die Method of impregnating a molten thermoplastic resin in roving (Japanese Patent Laid-Open No. 1987-60625, Japanese Patent Laid-Open No. 1988-132036, Japanese Patent Laid-Open No. 1988-264326, Japanese Patent Laid-Open No. 1989-208118 ), A method of impregnating the resin by mixing the roving of the resin fiber and the reinforcing fiber and then heating it above the melting point of the resin (Japanese Patent Laid-Open No. 1986-118235), and placing a plurality of rods inside the die. And a roving is wound in a zigzag shape and opened to impregnate the molten resin (Japanese Laid-Open Patent Publication No. 1998-264152). Any method such as the method (WO 97/19805) can be used.

In the process of melting the resin, an extruder having two or more feeders is used, and a separate resin is introduced from the upper feeder from the resin and the disintegrating agent of the resin (in the case of polypropylene resin, an organic peroxide is preferable) and the side feeder. can do.

In addition, two or more extruders (extrusion part) may be used, and one or more of the extruders may be charged with a resin and a disintegrating agent of the resin (in the case of polypropylene resin, an organic peroxide is preferable).

Moreover, resin, unsaturated carboxylic acid, its derivative (s), and a disintegrating agent (in the case of a polypropylene resin, organic peroxide is preferable) can also be put in at least 1 place of an extruder.

Short fiber reinforced resin pellets can be prepared by kneading and dispersing each component in a predetermined ratio in a roll mill, banbury mixer, kneader, etc. Dry blending can also be performed using a tumbler blender, a Henschel mixer, a ribbon mixer, or the like. Then, the resultant is kneaded by a single screw extruder, a twin screw extruder, or the like to form a pellet-shaped molding material, and the chopped strand of the fiber can be supplied from a side feeder.

The fiber reinforced resin composition of this invention can be shape | molded and can manufacture various molded articles.

As the molding method, known molding methods such as injection molding, extrusion molding, blow molding, compression molding, injection compression molding, gas injection molding or foam injection molding can be applied without any limitation. In particular, injection molding, compression molding and injection compression molding are preferred.

The fiber reinforced resin composition of the present invention may be a single pellet or a blend of pellets and diluents.

The blending of diluents, such as a fiber reinforced resin pellet and a thermoplastic resin, may be a dry blending system. In order to maintain the fiber length in a composition and to obtain the effect of improving the rigidity, impact resistance, and durability, it is preferable to provide it to molding machines, such as a direct injection molding machine, without passing an extruder after dry blending. The diluent may be the same as or different from the resin of the fiber reinforced pellets. Moreover, you may blend resin containing a pigment, an additive, a foaming agent, etc. together as a masterbatch. The blending ratio of the diluent is determined by the reinforcing fiber content of the pellets according to the fiber reinforcing resin and the reinforcing fiber content required for the final molded article, but is preferably 5 to 95% by weight in terms of fiber dispersion.

The weight average fiber length of the reinforcing fibers remaining after molding is usually at least 0.1 mm, preferably at least 1 mm. It is especially high that it is 2 mm or more.

The molded article preferably has a (vertical wall area) / (projection area from the gate side) of 0.3 to 4.8. It is preferable that average thickness is 0.2-5 mm. More preferably, it is 1-4 mm. The thinner the thickness, the greater the warpage and the less appropriate the strength of the molded article. In addition, when the thickness is too thick, voids are likely to occur.

Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to these Examples.

In addition, the various parameters in the table were measured with the following method.

(1) Melt Index (MFR)

In accordance with JIS K 7210-1999, it measured on conditions of the temperature of 230 degreeC, and 2.16 kg of loads.

(2) Storage modulus (G '), loss modulus (G ") and relaxation time (λ)

Measured with cone and plate rheometer.

Measuring instrument: Leometrics, system-4

Measuring part shape: cone and plate type

Measurement conditions: 175 ° C. and 30% strain (sinusoidal strain)

The storage modulus (G ') and the loss modulus (G ") are determined under the above conditions, and the relaxation time when the angular frequency ω = 1 (rad / sec) of the sinusoidal distortion provided to the disc is lambda (sec) = G '÷ (G "× ω) = G' ÷ G" was calculated and obtained.

On the other hand, regarding the measurement by a cone-and-plate rheometer, literature ['molding processing', 1 (4), 355 (1989)], literature ['Polymer experimental studies Vol. 9', mechanical properties 1, public publication ( 1982) and Japanese Patent Laid-Open No. 2003-226791.

(3) Weight average molecular weight (Mw), number average molecular weight (Mn) and Z average molecular weight (Mz), molecular weight of 10 ⁶ or more

Based on the method of Unexamined-Japanese-Patent No. 1999-71431, it calculated | required from the molecular weight distribution curve of polystyrene reference | standard by the gel permeation chromatography (GPC) method.

Measurement conditions are as follows.

Calibration curve: Universal Calibration

Column: 2 TOSOH GMHHR-H (S) HT

Solvent: 1,2,4-trichlorobenzene

Temperature: 145 ℃

Flow rate: 1.0ml / min

Detector: Waters alliance GPC2000 (RI)

Analysis program: HTGPC (v 1.00)

(4) crystallization temperature (Tc)

It was measured by DSC (differential scanning calorimeter).

Measuring device: Perkin Elmer, DSC7

Measurement conditions: After holding for 5 minutes at 220 degreeC, the peak peak (Tc) was calculated | required based on JISK7121 from the curve obtained by temperature-falling from 220 degreeC to 30 degreeC at 20 degreeC / min.

(5) Volume content rate (vol%) in the composition of reinforcing fibers

It calculated by the following formula.

V (volume%) = (W × P) ÷ {F × (100-W) + P × W} × 100

V: Volume content of reinforcing fibers (% by volume)

W: mass content of the fiber (wt%)

F: Specific gravity of reinforcing fiber (g / cm ³ )

P: specific gravity of resin part (g / cm ³ )

(6) bending elastic modulus and bending strength

It measured in accordance with JIS K 7171: 1994.

Preparation Examples 1 to 6

Using polypropylene resins having the properties shown in Table 1, raw resins (PP-A to PP-F) having the properties shown in Table 2 were prepared.

On the other hand, PP-A to PP-C and PP-F added peroxide (Kayaku Akujo Co., Ltd., Pacadox 14 (brand name)) to 100 parts by weight of the polypropylene resin of Table 1, and added the indicated amount (parts by weight) It was manufactured by melt kneading with a twin screw extruder (manufactured by Toshiba Machine, TEM-35B (trade name), barrel temperature: 200 ° C). In addition, PP-E was prepared by mixing PP-A and PP-C in a ratio of 50:50. In addition, PP-D used polypropylene resin (J-3003GV) as it was.

Examples 1-6, Comparative Examples 1 and 2

(Glass Fiber Reinforced Polypropylene Resin Composition)

The raw material resins (PP-A to PP-F) and the maleic acid-modified polypropylene resin (UNIROYAL CHEMICAL product, Polybond 3200 (trade name), specific gravity: 0.9 g / cm ³ ) It was mixed in the ratio shown in 3, melted at 280 ° C. and fed from the 50 mφ extruder into the impregnation bath in the die. Next, the glass roving which bundled about 4,000 glass fibers (made by Nihon Denki Glass Co., Ltd. product, ER2310T-441 (brand name), fiber diameter: 17 micrometers, specific gravity: 2.55 g / cm <^3> ) is shown in following Table 3 It was sent to the impregnation tank to which the said molten resin heated at 280 degreeC by the compounding quantity was supplied. Ten rods (diameter 10 mm) were arrange | positioned linearly in the impregnation tank. A glass roving preheated at 200 ° C. is sent into the impregnation tank while the feed rate is adjusted to 20 m / min. To obtain long fiber reinforced resin pellets (a to f) having a pellet length of 8 mm.

Next, the obtained pellets (a to f) and the raw material resins (PP-A to PP-F) were mixed (diluted blending) in the ratios shown in Table 4 below to prepare a glass fiber reinforced polypropylene resin composition.

Examples 7-15 and Comparative Examples 3-4

(Carbon Fiber Reinforced Polypropylene Resin Composition)

The raw material resins (PP-A to PP-F), the maleic acid-modified polypropylene resin and carbon fiber (Tohotenax product, HTA-C6-SRS (trade name), fiber diameter: 7 μm, specific gravity: 1.8 g / cm ³ , treated with an epoxy-based sizing agent) at a ratio shown in Table 5 below, followed by a twin screw extruder (manufactured by Toshiba Machine, TEM-35B (trade name), barrel temperature: 200 ° C., screw rotation from the upper feeder). Water: 300 rpm) and melt kneading to prepare a carbon fiber reinforced polypropylene resin composition.

(evaluation)

Box shape (thickness 3mm) of 200 (w) x 100 (L) x 40 (h) using the resin composition obtained by the said Example and the comparative example using the molding machine (Nissei resin industry product, AZ7000 (brand name)). (Constant) and fin gate / φ 1.5 mm (1 point, cold)), and the curvature was evaluated. The figure of this molded article and its expanded view are shown to FIG. 1 and FIG. 2, respectively.

Molding conditions are as follows.

Resin temperature: 220 ℃

Mold temperature: 40 ℃

Injection retention time: 15 seconds (primary charge time: 2 seconds)

Resin Back Pressure: 5MPa

Cooling time: 35 seconds

The (vertical wall area) / (projection area from the gate side) of this molded article was {(200 × 2 + 100 × 2) × 40} ÷ (200 × 100) = 1.2.

The curvature of the molded article is after molding the resin composition, aged at room temperature (23 ℃) for 48 hours or more, and then placed the molded article with the gate portion on the flat plate, and press the end of the molded article to measure the distance raised from the diagonal flat plate did. Four edge parts were pressed and the largest value was made into the bending value. The results are shown in Tables 4 and 5.

Molded products formed by molding the resin composition of the present invention is used for automobile parts (front end, fan shroud, cooling fan, engine under cover, engine cover, radiator box, side door, back door inner, back door outer, outer plate, roof rail, Door handles, luggage boxes, wheel covers, handles, cooling modules, air cleaners, lock nuts), two-wheeled bicycle parts (luggage boxes, handles, wheels), housing-related parts (hot water cleaning toilet parts, bathroom parts, bathtub parts , Chair legs, valves, meter box), washing machine parts (water tank / balance ring, etc.), wind generator fan, power tool parts, first handle, hose joint, resin bolt, concrete frame, etc. .

The molded article of the present invention is particularly effective for bathtub parts (bath tubs, bath fans), luggage boxes, air cleaner cases, engine covers, personal computers, IC trays and the like having vertical walls or ribs.

Claims (7)

(A) relaxation time λ = at angular frequency ω = 1 (rad / sec) calculated from storage modulus (G ') and loss modulus (G ") measured with a corn and plate rheometer 99 to 80% by volume of polyolefin resin having G '÷ (G "xω) of 0.2 (sec) or less, and (B) 1 to 20% by volume of reinforcing fibers Fiber reinforced polyolefin-based resin composition comprising a. The method of claim 1, A fiber-reinforced polyolefin resin composition having a weight average molecular weight (Mw) of 90,000 to 300,000 and a Z average molecular weight (Mz) of 100,000 to 600,000 as measured by gel permeation chromatography (GPC) of the polyolefin resin (A). The method of claim 1, A fiber-reinforced polyolefin resin composition wherein the reinforcing fibers (B) are glass fibers having a fiber diameter of 3 to 30 µm. The method of claim 1, The fiber-reinforced polyolefin resin composition wherein the reinforcing fibers (B) are carbon fibers having a fiber diameter of 3 to 30 µm. The method of claim 1, A fiber-reinforced polyolefin resin composition further comprising a polyolefin resin modified with 0.1 to 50 parts of an unsaturated carboxylic acid or a derivative thereof, based on 100 parts of the polyolefin resin (A). The molded article formed by shape | molding the fiber reinforced polyolefin resin composition of Claim 1. The method of claim 6, Molded articles with vertical walls or ribs.

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