JP2005068225A - Composite molding material and molding using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provided a composite molding material which consists of an organic fiber and a matrix resin, is effective in preventing environmental pollution because of its excellence in thermal recyclability, exhibits an excellent moldability and renders the molding excellent physical properties and a molding using the material. <P>SOLUTION: The composite molding material mainly comprises an organic fiber and a matrix resin. The organic fiber satisfies requirements (1)-(4). (1) Single filament fineness: ≥10 dtex; (2) Strength: ≥1 Gpa; (3) Modulus: ≥40 GPa; (4) Dry heat shrinkage at 160°C: ≤1%. Also presented are an injection-molded molding, a compression-molded molding and a filament winding-molded molding using the composite molding material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composite molding material that can be suitably used for vehicle applications such as automobiles and railways, aerospace field, architectural civil engineering / housing materials, electrical / electronic equipment, household appliances, safety equipment, daily necessities, etc. The present invention relates to a molded article, and relates to a composite molding material and a molded article that can be thermally recycled by 99% or more and have a low environmental load.

  In recent years, from the viewpoint of reducing the environmental burden, the disposal method of molded products has become a problem. For example, in home appliances such as televisions, reuse such as reuse of molding materials that have been used once, and thermal recycling such as incineration in a high-temperature furnace to extract thermal energy are being actively studied.

However, for example, in a molded product using glass fiber, glass fiber remains as a residue, so that 100% recycling is not possible, and disposal of industrial waste is becoming a problem.
Under such circumstances, in recent years, composite molding materials reinforced or reinforced with organic fibers so that thermal recycling close to 100% is possible have been studied.
For example, Patent Document 1 discloses a master batch of an organic fiber reinforced resin composition containing 1 to 90% by mass of organic fibers impregnated with a thermoplastic resin having a melt viscosity of 4 Pa / s or less and a molecular weight of 1000 or more. ing. According to this patent, conventionally, the difficulty of kneading due to the specific gravity of organic fibers being light and bulky, and the appearance defects and strength that occur when air layers (hereinafter referred to as voids) existing between organic fibers are removed. The shortage can be solved by adjusting the resin viscosity. And in order to impregnate the organic fiber with a high-viscosity thermoplastic resin, the voids existing between the organic fibers are reduced by passing through a thermoplastic resin that has been heated to a low-viscosity organic fiber that has been previously opened, It is said that pellets with few defects can be obtained. In this patent, there is no detailed description of the masterbatch manufacturing method, but a resin that depends on the processing speed when, for example, polyester fiber is brought into contact with a thermoplastic resin having a resin temperature of 200 ° C. whose melt viscosity is defined in the claims. Depending on the shear viscosity acting between the fibers and the tension applied to the fibers, the strength of the fibers is exceeded, and there is a disadvantage that the operation cannot be performed.
Patent Document 2 discloses an organic fiber reinforced polyolefin resin composition. According to this patent, an organic fiber having a melting point higher than that of polyolefin resin by 50 ° C. or higher is used as a reinforcing material, and the polyolefin resin is heated to a temperature higher by 40 ° C. or higher than the melting point, and the immersion time does not exceed 6 seconds. And impregnating the organic fiber. Compared with melt-kneading in a mixer with heating and stirring / kneading, rolls, extruders, kneaders, etc., it does not cause thermal deterioration of the reinforcing fibers, and there is little breakage, and an excellent organic fiber-reinforced resin composition can be obtained. Yes. By pulling out organic fibers from the polyolefin resin resin bath in a twisted state, resin impregnation is promoted between the fibers in the reinforcing fiber bundle, and an organic fiber reinforced resin composition having excellent strength is obtained. I can do it. However, in this method, twist remains in the organic fiber reinforced resin composition. For example, when the organic fiber reinforced resin composition is used as a pellet for injection molding, the fiber bundle in which the reinforced fiber is twisted is retained. Therefore, there is a drawback that the dispersibility of the reinforcing fiber bundle is deteriorated in the molded product.

JP 2001-234076 A JP 2001-49012 A

  The present invention provides a composite molding material and a molded article comprising an organic fiber and a matrix resin, which are excellent in thermal recyclability, effective in preventing environmental pollution, excellent in moldability and physical properties of a molded article, and also excellent in cost performance. It is something to be offered.

That is, the present invention employs the following configuration.
1. A composite molding material whose main components are organic fibers and a matrix resin, wherein the organic fibers satisfy the following requirements (1) to (4).
(1) Single yarn fineness of 10 dtex or more (2) Strength of 1 GPa or more (3) Elastic modulus of 40 GPa or more (4) Dry heat shrinkage at 160 ° C. of 1% or less The molding material according to the first invention, wherein the organic fiber is a copolyester fiber.
3. The composite molding material according to the second invention, wherein the main acid components of the copolyester are terephthalic acid and biphenyldicarboxylic acid.
4). A molded article obtained by injection molding using a pellet obtained by cutting the composite molding material according to any one of the first to third inventions.
5). A molded article obtained by compression molding the composite molding material according to any one of the first to third inventions.
6). A molded product obtained by filament winding molding the composite molding material according to any one of the first to third inventions.

  The fiber / resin composite molding material in the present invention is (1) single yarn fineness of 10 dtex or more, (2) strength of 1 GPa or more, (3) elastic modulus of 40 GPa or more, and (4) dry heat shrinkage at 160 ° C. Because it uses organic fibers with a 1% or less, 99% or more can be thermally recycled, has low environmental impact, has excellent moldability and physical properties of molded products, is used for vehicles such as automobiles and railways, and aerospace. It is possible to provide molding materials and molded articles suitable for fields, architectural civil engineering / housing materials, electrical / electronic equipment, household appliances, safety equipment, daily necessities, and the like.

Hereinafter, the present invention will be described in detail.
The organic fiber in the present invention has a single yarn fineness of 10 dtex or more, a strength of 1 GPa or more, an elastic modulus of 40 GPa or more, and a shrinkage at 160 ° C. of 1% or less.

  First, the single yarn fineness of the organic fiber in the present invention is 10 dtex or more. This is because, as described above, if it is made thinner than 10 dtex in order to obtain the strength and elastic modulus, the rigidity of the single yarn becomes small. For example, organic fibers that have fallen off during injection molding become pills, which significantly impairs the moldability. Born. In order to prevent this, twisting may be applied, but the twisting deteriorates the openability, and the dispersion of the organic fibers becomes non-uniform when molded. In contrast, in the present invention, by using a fiber having a single yarn fineness of 10 dtex or more, the bending rigidity of the fiber is improved. For example, when it is used as a pellet for injection molding, it can be used without being twisted, and the rigidity is high. Since it is high, it has the effect of being uniformly dispersed during molding. The single yarn fineness is 10 dtex or more as described above, and the upper limit of no problem in the practical range is 2000 dtex. More preferably, it is 10 dtex-1000 dtex, More preferably, it is 10 dtex-500 dtex.

  The organic fiber in the present invention has a strength of 1 GPa or more and an elastic modulus of 40 GPa or more. When the strength and elastic modulus are smaller than these values, a sufficient reinforcing effect cannot be obtained. Higher strength is preferable, but it is technically difficult to obtain a fiber having a strength of substantially 2.5 GPa and an elastic modulus of 55 GPa.

  Moreover, the shrinkage rate at 160 ° C. is 1% or less. Considering a combination with a resin as a molding material, a smaller shrinkage rate is preferable. This greatly affects the shrinkage rate of the molded product, and if it exceeds 1% and becomes 1.5%, for example, when injection molding is performed, sink marks and the like are not preferable. A more preferable range is 0.5% or less. Technically, it is difficult to obtain a shrinkage rate of 0%, and the level possible for industrial production is 0.1%.

  The organic fiber material in the present invention is preferably a copolyester. Of these, a combination of terephthalic acid and 4,4'-dicarboxylic acid among the acid components of the copolyester is preferred. Furthermore, the proportion of terephthalic acid and 4,4'-dicarboxylic acid in the total acid component is preferably 90 mol% or more. If it is less than 90 mol%, it may be difficult to achieve sufficient physical properties.

  The copolyester used for the fiber in the present invention can be used as long as the acid component other than terephthalic acid and 4,4'-dicarboxylic acid does not impair the object of the present invention. For example, as the dicarboxylic acid, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 1 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, dimer acid Saturated aliphatic dicarboxylic acids exemplified by the above, or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acids exemplified by fumaric acid, maleic acid, itaconic acid, etc., or ester-forming derivatives thereof, orthophthalic acid, isophthalic acid , Terephthalic acid, 5- (alkaline Metal) sulfoisophthalic acid, diphenic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4 4'-biphenyldicarboxylic acid, 4,4'-biphenylsulfone dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid, pamoic acid, anthracene Examples thereof include aromatic dicarboxylic acids exemplified by dicarboxylic acids and the like, and ester-forming derivatives thereof.

  Of these dicarboxylic acids, terephthalic acid and naphthalenedicarboxylic acid, particularly 2,6-naphthalenedicarboxylic acid, are preferable from the viewpoint of the physical properties of the resulting polyester, and other dicarboxylic acids are used as constituents as necessary.

  As polyvalent carboxylic acids other than these dicarboxylic acids, ethanetricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3, 4, 3 ', 4'-biphenyltetracarboxylic acid, And ester-forming derivatives thereof.

Any glycol can be used for the glycol component of the copolyester used in the fibers represented by the present invention.
For example, glycols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 2,3-butylene glycol. 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1, 2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, polyethylene glycol, polytrimethylene Glycol, polyte Aliphatic glycols exemplified by tramethylene glycol, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-bis (β-hydroxyethoxyphenyl) sulfone, Bis (p-hydroxyphenyl) ether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p-hydroxyphenyl) ethane, bisphenol A, bisphenol C, 2,5- Examples include aromatic glycols exemplified by naphthalenediol, glycols obtained by adding ethylene oxide to these glycols, and the like.

  Examples of polyhydric alcohols other than these glycols include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, hexanetriol and the like.

Furthermore, since it becomes possible to align the alignment more easily, among these glycols, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,5-pentane. Diol, 1,6-hexanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol are preferred. Of these, ethylene glycol, 1,3-propylene glycol, and 1,4-butylene glycol are particularly preferred from the viewpoint of processability. Further, other hydroxycarboxylic acids and their ester-forming derivatives may be copolymerized.
For example, as hydroxycarboxylic acid, lactic acid, citric acid, malic acid, tartaric acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, 4-hydroxycyclohexanecarboxylic acid, Or these ester forming derivatives are mentioned.
Examples of ester-forming derivatives of polyvalent carboxylic acids or hydroxycarboxylic acids include these alkyl esters, acid chlorides, acid anhydrides, and the like.

  In the present invention, the rigid 4,4'-bisbenzoate unit is considered to play a role as a mesogenic group. Therefore, the 4,4′-bisbenzoate unit in the polyester is preferably 40 mol% or more based on the total polyester. If the 4,4'-bisbenzoate unit is 40 mol% or less, the liquid crystallinity is insufficient, and the molecular orientation does not proceed, making it difficult to obtain sufficient physical properties after melt spinning.

  The 4,4'-bisbenzoate unit in the polyester is preferably 75 mol% or less based on the total polyester. When the 4,4'-bisbenzoate unit is 75 mol% or more, the molecular rigidity is too high, and the viscosity fluctuation at the time of melt discharge becomes too large, which may make it difficult to process.

Specifically, the spinning condition of the organic fiber in the present invention is preferably that the spinning draft (DDR) is spun in the region where the shear rate is 1000 (sec ⁻¹ ) or less and the draft satisfies the following formula (A). .
6000 × exp (0.0095 × γ) ≦ DDR ≦ 8000 × exp (0.0095 × γ) (B)
Where γ is the shear rate ((sec ^-1 )
DDR: spinning draft

  A higher shear rate during spinning is expected to improve physical properties. This is because structure formation in the fiber proceeds by shearing during spinning. However, if the shearing stress at the time of spinning is too high, the viscosity drop due to shearing is large, and unstable behavior such as melt fracture is induced.

  Higher drafts during spinning are expected to improve physical properties. This is because a structure is formed in the fiber by the elongational flow during spinning. However, if the spinning draft is too high, unstable behavior such as draw resonance is induced, and uniform fibers cannot be obtained.

  In order to obtain high-performance fibers with high productivity while suppressing unstable behavior during spinning, the present inventors use a specially-shaped spinneret, and the yarn is held by a heat retaining cylinder under the spinneret. Heating was carried out, the shear rate and the spinning draft were controlled, and the conditions for obtaining these fibers in the present invention were found.

  For example, in the case of polyester, the temperature of the spinneret varies depending on the copolymerization rate and intrinsic viscosity of the polymer used, but is preferably about 250 to 350 ° C. More preferably, about 300-320 degreeC is preferable. When the die temperature is lower than 250 ° C., the viscosity of the molten polymer becomes too high and spinning becomes difficult. When the spinneret temperature exceeds 350 ° C., the deterioration rate of the polymer increases and the physical properties tend to decrease. The yarn extruded in the molten state is cooled and solidified before winding. It is necessary to control the nozzle shear rate during spinning. In order to increase productivity, it is preferable that the shear rate is high. However, if the shear rate exceeds 1000, melt fracture occurs and spinning becomes difficult. In order to control the shear rate, it is necessary to control the hole diameter of the spinneret nozzle.

The deformation rate of the yarn must be sufficient to allow the isotropic melt to transfer to the pseudo liquid crystal. The spinning speed required for this varies depending on the composition of the polymer, the degree of polymerization, and the discharge shear rate, but is usually 200 m / min or more. More preferably, the fiber having the desired physical properties can be easily obtained by spinning at 400 m / min or more. However, at 2000 m / min or more, draw resonance occurs and spinning becomes difficult.
The fibers thus obtained are organic fibers having a strength of 1 GPa, an elastic modulus of 40 GPa or more, and a shrinkage at 160 ° C. of 1% or less regardless of the fineness.

The organic fiber thus obtained is combined with a matrix resin to become a molding material. The matrix resin in the present invention may be either a thermoplastic resin or a thermosetting resin, but is preferably a thermoplastic resin in the sense that it has less adverse effects on the environment and improves the degree of freedom in post-processing.
As the thermosetting resin, commercially available unsaturated polyester resins, epoxy resins, melamine resins, and the like can be used. As the thermoplastic resin, general-purpose, high-performance engineering plastic resins such as polyolefin resins, polyester resins, and polyamide resins, and thermoplastic elastomers such as polyolefin elastomers and polyester elastomers can be used.

As a method of combining organic fibers with a matrix resin to form a molding material, 1) a melt impregnation method, 2) a powder impregnation method, 3) a core-sheath spinning method, or the like can be used.
In the melt impregnation method, a molding material can be obtained by opening the organic fiber bundle, coating and impregnating with a molten resin, and drawing it from a die. Further, in the powder impregnation method, a molding material can be obtained by passing through an organic fiber bundle that has been opened in the emulsion of resin powder and then drying. In the core-sheath spinning method, molding can be performed by two-component spinning using the copolymer polyester as a core and a resin as a sheath from the same nozzle. In this case, the productivity is greatly improved, but it is preferable to sufficiently perform stretching in one stage of spinning in order to obtain the above-described spinning draft.

  The composite molding material thus obtained can be cut into a length of, for example, 1 to 10 mm to obtain injection molding pellets. Further, the material for compression molding can be obtained by cutting into a length of 10 to 100 mm, depositing non-oriented, and lightly fusing within a temperature range in which only the resin does not melt and the organic fiber does not melt. Further, the molding material can be flattened and used for filament winding molding by heating and winding the mandrel to a temperature range in which the organic fiber does not melt but only the resin melts.

  The molded product thus obtained is a molded product that is lightweight, high in strength and rigidity, excellent in impact resistance, and capable of thermal recycling by 99% or more.

Examples are shown below. The evaluation methods employed in the present invention are as follows.
(I) Evaluation of organic fiber:
(Measurement method of strength and initial elastic modulus)
Using a constant-speed extension type tensile tester at 20 ° C. and 65% RH, applying an initial load of 1/33 g of fineness (dtex) to a sample having a sample length of 200 mm and pulling at a pulling rate of 200 mm / min. The maximum point stress is the strength. The initial elastic modulus is a stress at a position corresponding to a 10% elongation of the sample by extending the rise from the origin of the load-extension curve with a straight line.
(Method of measuring dry heat shrinkage)
The sample length L1 is measured by applying a load of 1/33 g of the fineness (dtex) of the sample. This sample is treated at 160 ° C. for 30 minutes under no load and then allowed to cool at room temperature. This sample was subjected to the same load as described above, and the sample length L2 was measured and obtained using the following equation.
S = (L1-L2) / L1 x 100

(Ii) Evaluation of molded products:
The obtained pellets were molded into physical property measurement test pieces (JIS standard) at an injection temperature of 200 ° C. (mold temperature: 40 ° C.) using an injection molding machine (JSW J200SA manufactured by Nippon Steel Co., Ltd.). An evaluation test was conducted on a bending test and an Izod impact test.
Flexural strength (MPa), flexural modulus (MPa): Conforms to JIS K7203.
-Izod impact test (J / m): compliant with JIS K7110.
(Iii) Fiber mass content (%):
The organic fiber content in the molding material (roving) was calculated from the fineness of the organic fiber used and the fineness and mass of the roving after impregnating the resin.

(Example 1)
An esterification reaction was carried out according to a conventional method using 187 parts of ethylene glycol and 187 parts of dimethyl terephthalate and 318 parts of 4,4′-biphenyldicarboxylic acid. Subsequently, a polycondensation reaction was performed according to a conventional method. The above polymer was subjected to solid phase polymerization at 210 ° C. for 48 hours to obtain a solid phase polymerization chip with IV = 1.23. This chip was spun at an spinning temperature of 310 ° C. with an extruder-type spinning machine. At this time, a 1000 mesh metal woven fabric was used as the filter, and a 6.5 mmφ round hole was used as the base. The yarn discharged from the die was cooled by a heating cylinder having a length of 80 cm and an inner diameter of 5 cm, and then taken up at a constant take-up speed. This yarn was heat-treated in an oven at 210 ° C. under vacuum. The properties of the obtained reinforcing fiber are shown in Table 1.

  While opening the copolymer polyester fiber bundle obtained in this way, the polypropylene resin was passed through a resin impregnation apparatus filled with polypropylene resin (Grand Polypro J105W manufactured by Grand Polymer Co., Ltd.) heated and melted to 200 ° C. After impregnation, the resin was bundled and unnecessary resin was removed with a die to obtain a polypropylene resin composite molding material having a fiber mass content of 30% by mass. This molding material was cut into a length of 5 mm, injection molded, and the evaluation results are shown in Table 2.

(Example 2)
The spinning draft and fineness reinforcing fibers shown in Table 1 were obtained. Further, composite molding materials were obtained in the same manner as in Example 1, and the evaluation results in the same manner as in Example 1 are shown in Table 2.
(Example 3)
The spinning draft and fineness reinforcing fibers shown in Table 1 were obtained. Further, molding materials were obtained in the same manner as in Example 1, and the evaluation results in the same manner as in Example 1 are shown in Table 2.
(Comparative Example 1)
The spinning draft and fineness reinforcing fibers shown in Table 1 were obtained. Further, composite molding materials were obtained in the same manner as in Example 1, and the evaluation results in the same manner as in Example 1 are shown in Table 2.

Example 4
The molding material obtained in Example 1 was cut into a length of 25 mm and thermocompression bonded for 1 minute in a hot press at a temperature of 200 ° C. to obtain a stamping molding material. When this was stamped and molded using a mold having a T-shaped groove, there was no sink and a molded article having a good appearance could be obtained.
(Example 5)
The molding material obtained in Example 1 was again heated to 220 ° C. and wound around a hollow steel tube having a diameter of 50 mm to perform filament winding molding. As a result, a filament winding circular tube having a good appearance and excellent demoldability was obtained. In addition, when this molded product was incinerated at 450 ° C. for 8 hours in an electric furnace, the residue was 0.1%.

  The fiber / resin composite molding material in the present invention uses specific organic fibers as reinforcing fibers, so that thermal recycling of 99% or more is possible, environmental impact is small, and moldability and molded article physical properties are excellent. We can provide molding materials and molded products, and can be used in a wide range of applications such as vehicles such as automobiles and railways, aerospace, architectural and residential construction materials, electrical and electronic equipment, household appliances, safety equipment, and daily necessities. It can be used suitably.

Claims (6)

A composite molding material whose main components are organic fibers and a matrix resin, wherein the organic fibers satisfy the following requirements (1) to (4).
(1) Single yarn fineness of 10 dtex or more (2) Strength of 1 GPa or more (3) Elastic modulus of 40 GPa or more (4) Dry heat shrinkage at 160 ° C. of 1% or less   The composite molding material according to claim 1, wherein the organic fiber is a copolyester fiber.   3. The composite molding material according to claim 2, wherein the main acid components of the copolyester are terephthalic acid and biphenyldicarboxylic acid.   A molded article obtained by injection molding using a pellet obtained by cutting the composite molding material according to claim 1.   A molded article obtained by compression molding the molding material according to claim 1.   A molded article obtained by filament winding molding the composite molding material according to any one of claims 1 to 3.