JP2007070516A - Fiber-reinforced polycaprolactone and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber-reinforced polycaprolactone the matrix resin of which is a crosslinked polycaprolactone and to provide a method for producing a fiber-reinforced polycaprolactone comprising fully impregnating a reinforcing fiber base with a matrix resin. <P>SOLUTION: The method for producing the fiber-reinforced polycaprolactone comprises laminating a pellet material or a sheet material of polycaprolactone containing an organic peroxide on a reinforcing fiber base, applying heat and pressure to the laminate to impregnate the reinforcing fiber base with the polycaprolactone and to crosslink the polycaprolactone. The fiber-reinforced polycaprolactone is one wherein the reinforcing material is a reinforcing fiber, and the matrix resin is a polycaprolactone prepared by crosslinking a polycaprolactone of a number-average molecular weight of not less than 10,000 and having a gel fraction of not less than 50% as measured by extraction with cyclohexanone at 100°C for 24 hr. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fiber reinforced thermoplastic resin having a crosslinked polycaprolactone as a matrix.

  Fiber reinforced thermoplastic resins are widely used in the field of industrial materials. For example, according to Patent Document 1, fiber reinforced fibers obtained by injection molding using plant cellulose fibers as reinforced fibers and biodegradable resins such as polycaprolactone as matrix resins. A thermoplastic resin is disclosed. Polycaprolactone is a thermoplastic polyester resin that exhibits crystallinity, flexibility, and biodegradability, and is known as a modeling material that can be deformed with hot air or hot water using its low melting point of 60 ° C. It has been. However, there is a drawback that fluid deformation is remarkable near the melting point, and the fiber-reinforced polycaprolactone of Patent Document 1 does not overcome the disadvantage that fluid deformation is remarkable near the melting point. As a technique for suppressing fluid deformation near the melting point, for example, Patent Document 2 and Patent Document 3 disclose that fluidity can be suppressed by crosslinking polycaprolactone. However, even if polycaprolactone forms a cross-linked structure, the strength and elastic modulus of the resin itself are low and it is not suitable for applications where a load is applied. In addition, as a negative effect of suppressing fluidity in the vicinity of the melting point of the crosslinked caprolactone, very high temperature and pressure are required to impregnate the reinforcing fiber base material, and the reinforcing fiber base material is sufficiently impregnated. Thus, the strength and the elastic modulus cannot be sufficiently satisfied, and therefore, fiber-reinforced crosslinked polycaprolactone has not been put into practical use.

JP 2001-335710 A JP 59-108059 A JP 59-207156

  An object of the present invention is to provide a fiber-reinforced polycaprolactone using a crosslinked polycaprolactone as a matrix resin, and a method for producing a fiber-reinforced polycaprolactone in which a matrix resin is sufficiently impregnated into a reinforcing fiber substrate.

  The present invention includes a polycaprolactone pellet material or sheet material containing an organic peroxide and a reinforcing fiber base material, heated and pressurized, impregnated with the above-mentioned polycaprolactone base material, and the polycaprolactone A method for producing a fiber-reinforced polycaprolactone characterized by crosslinking. In the polycaprolactone pellet or sheet material containing the organic peroxide, the polycaprolactone preferably has a number average molecular weight of 10,000 to 65,000. The fiber length of the reinforcing fiber of the reinforcing fiber base can be 10 mm or more.

  The present invention also provides a reinforcing fiber as a reinforcing material, a polycaprolactone having a number average molecular weight of 10,000 or more crosslinked, and a gel content of 50% or more when extracted in cyclohexanone at 100 ° C. for 24 hours. It is also a fiber reinforced polycaprolactone characterized by using caprolactone as a matrix resin. At this time, the fiber length of the reinforcing fiber may be 10 mm or more.

  In the fiber-reinforced polycaprolactone production method of the present invention, the polycaprolactone pellet material or sheet material containing an organic peroxide is in a state where the polycaprolactone is not crosslinked or hardly crosslinked, and is reinforced by heating and pressing. A fiber reinforced polycaprolactone having a sufficient strength and elastic modulus can be obtained by sufficiently impregnating the fiber base material and heating and pressing. In addition, when the number average molecular weight is 10,000 to 65,000, a sheet material or a pellet material containing an organic peroxide can be easily obtained, and a molded product having more excellent characteristics can be obtained.

  In particular, reinforcing fibers having a fiber length of 10 mm or more are in a state where a plurality of single fibers are bundled when the resin is impregnated. Even in such a case, the resin can be sufficiently impregnated.

  Moreover, since the reinforcing fiber base material and the polycaprolactone pellet material or sheet material are laminated and molded by heating and pressing, a fiber or continuous fiber base material having a fiber length of 10 mm or more can be used, and injection molding is performed. As in the case of the above, since the reinforcing fiber is hardly shredded and is maintained as a long fiber in the molded product, a fiber-reinforced polycaprolactone having excellent strength and elastic modulus can be obtained.

  Furthermore, in this heating and pressurizing step, polycaprolactone is crosslinked with an organic peroxide. Therefore, the fiber-reinforced polycaprolactone of the present invention has little work deformation near the melting point, and has excellent workability without stickiness even when modeling with hot water or hot air.

  The polycaprolactone in the production method of the present invention is a polymer of ε-caprolactone, and can be obtained by adding a polymerization initiator to ε-caprolactone and polymerizing it using a catalyst as necessary. As reaction temperature, it is 120-220 degreeC, for example, Preferably it can obtain by making it react under stirring for several hours at 150-200 degreeC.

  Examples of the polymerization initiator include alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butylene glycol, pentamethylene glycol, hexamethylene glycol; isophthalyl alcohol, terephthalyl alcohol, β , Β′-bishydroxyethyl terephthalate, β, β′-bishydroxyethyl isophthalate and other aromatic diols; cyclohexane 1,4-diol, cyclohexane 1,4-dimethanol and other alicyclic diols; polyethylene glycol, polypropylene Glycol, polytetramethylene glycol, polyethylene adipate diol, polypropylene adipate diol, polybutylene adipate diol, polyethylene sebacate diol, polyethylene Ropi diol, and polyethylene butylene adipate diol.

  Examples of the catalyst include tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, dibutyltin oxide, dibutyltin laurate, tin octylate, stannous chloride, and the like. The amount of catalyst used is preferably 0.5 to 500 ppm.

  In the present invention, the number average molecular weight of polycaprolactone is preferably 10,000 to 65,000, more preferably 30,000 to 60,000. If the number average molecular weight is less than 10,000, the mechanical strength and heat resistance which must be provided in the resin itself may not be sufficient, which is not preferable. If the number average molecular weight exceeds 65,000, the reinforcing fiber base may not be sufficiently impregnated due to the large viscosity coefficient even by heating during molding, and operations such as dissolving polycaprolactone in a solvent may be required. This is undesirable. The number average molecular weight can be measured by gel permeation chromatography using THF, toluene, chloroform or the like as a mobile phase and polystyrene standard particles as a molecular weight standard.

  In the present invention, an organic peroxide is contained in the polycaprolactone pellet or sheet material, and polycaprolactone is crosslinked with the organic peroxide by heating and pressurizing as described later. Examples of the organic peroxide include octanoyl peroxide, lauryl peroxide, stearoyl peroxide, acetyl peroxide, benzoyl peroxide, t-butyl peroxymaleic acid, t-butyl peroxyisobutyrate, and methyl ethyl ketone. Peroxide, dicumyl peroxide, di-t-butyl hydroperoxide, di-t-butyl peroxide, p-mensen hydroperoxide, pinane hydroperoxide, 2,5-dimethyl-2,5-di ( t-butylperoxy) hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3,2,5-dimethylhexane-2,5-dihydroperoxide, cumene hydroperoxide Etc.

  The amount of the organic peroxide used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of polycaprolactone. The heating temperature for crosslinking is preferably 140 to 220 ° C. The time required for the crosslinking reaction is usually about 10 minutes to 3 hours.

  The organic peroxide is decomposed to generate free radicals, drawing hydrogen in the polymer to form a carbon-carbon bond between the molecules and crosslinking the polymer chain. The decomposition of the organic peroxide can be performed by heating alone or in combination with an accelerator. As this accelerator, for example, dimethylaniline capable of generating a radical by reacting an amino group with an organic peroxide is preferable.

  In the present invention, in order to obtain a polycaprolactone pellet material or sheet material containing an organic peroxide, the organic peroxide is added to the polycaprolactone once under a condition (for example, 90 to 110) below the activation temperature of the organic peroxide. And blended by a method such as melt kneading at a temperature of 0 ° C.) to form pellets or sheets.

  Examples of the material of the reinforcing fiber base in the present invention include synthetic fibers such as polyamide fibers and polyvinyl alcohol fibers, as well as organic fibers such as aramid and vinylon, and inorganic fibers such as glass fibers and carbon fibers; Cannabis, flax, burlap, etc.) fiber, bamboo fiber, pulp, cotton fiber, coco fiber, natural fiber such as wool, silk, banana, kenaf, and regenerated fiber such as rayon.

Moreover, in order to improve the strength of the fiber-reinforced polycaprolactone, the reinforcing fiber preferably has a fiber length of 10 mm or more, and more preferably a long fiber of 20 mm or more or a continuous long fiber. Moreover, it is preferable that the count of a fiber bundle is 100-2000 tex, and in the case of a planar body, it is preferable that unit weight is 10-300 g / m < ² >.

  In the present invention, examples of the form of the reinforcing fiber substrate include a unidirectional substrate, a woven fabric, a knitted fabric, a braided fabric, or a combination thereof, a knitted fabric, a chopped strand mat, or a mat substrate of a continuous fiber mat. it can.

  In addition, the reinforcing fiber base may be surface-treated in order to improve adhesion with polycaprolactone. For example, if it is glass fiber, you may process with a silane coupling agent. The silane coupling agent is a silane compound having a hydrolyzable group and a hydrophobic group (organic group), such as vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Those having an unsaturated double bond such as (methacryloyloxypropyl) trimethoxysilane; β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxy Those having an epoxy group such as silane; γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N -Β- (N-vinylbenzylaminoethyl Aminosilane compounds having -γ- aminopropyltrimethoxysilane amino group and the like. These can use 1 type (s) or 2 or more types. Of these, (meth) acrylsilane compounds and aminosilane compounds are preferred.

  In the production method of the present invention, polycaprolactone is crosslinked in parallel with molding by heating and pressing, and therefore the heating temperature is set to be equal to or higher than the activation temperature of the organic peroxide, for example, 140 to 220 ° C. Since the time required for the crosslinking reaction is usually about 10 minutes to 3 hours, the heating and pressing time is set in consideration of this.

  In addition, you may provide the process bridge | crosslinked by heating or ultraviolet irradiation or radiation irradiation separately from this heating-pressing process.

  Polycaprolactone is crosslinked to the extent that the gel content when extracted in cyclohexanone at 100 ° C. for 24 hours is in the range of 50 to 100%, the degree of stickiness of the resin is small when the molded body is heated, Since it is excellent in heat resistance, it is preferable. The gel content is more preferably 70 to 100%, further preferably 80 to 100%, and still more preferably 90 to 100%.

  In heat and pressure molding, one layer or plural layers of polycaprolactone pellets or sheets may be sandwiched between layers of reinforcing fiber substrates, and polycaprolactone pellets or sheets between multiple layers of reinforcing fiber substrates. It is also possible to sandwich the material. A plurality of types of reinforcing fiber base materials may be combined. When laminating multiple layers of reinforcing fiber base material, the fiber direction of the reinforcing fiber base material may be aligned or changed, and load resistance is adjusted by changing the fiber direction and laminating. be able to.

  The weight blend of the reinforcing fiber base material and the matrix resin may vary depending on the type of fiber. For example, in the case of glass fiber, the reinforcing fiber base material is 10 to 80% by weight based on the total weight of the fiber reinforced polycaprolactone. Preferably, 20 to 70% by weight is more preferable. If the amount of the reinforcing fiber base is less than 10% by weight, the physical properties of the molded product tend to be low or warpage and undulation tend to increase. If the amount exceeds 80% by weight, the fiber tends to be unimpregnated with the resin It is in. Even with other types of fibers, the blending ratio can be determined as appropriate with reference to the above values.

  The fiber-reinforced polycaprolactone of the present invention uses a reinforcing fiber as a reinforcing material, and a crosslinked polycaprolactone formed by crosslinking a polycaprolactone having a number average molecular weight of 10,000 or more as a matrix resin. As the reinforcing fiber, those described above can be preferably applied.

  Furthermore, in the fiber reinforced polycaprolactone of the present invention, the polycaprolactone has a gel content in the range of 50 to 100% when extracted in cyclohexanone at 100 ° C. for 24 hours, preferably 70 to 100%, more preferably It is crosslinked to the extent of 80 to 100%, more preferably 90 to 100%.

  Such a fiber-reinforced polycaprolactone of the present invention can be suitably produced by the production method of the present invention described above, but is not necessarily limited thereto, and particularly if necessary, referring to the above description. When the number average molecular weight of polycaprolactone is large, for example, an operation such as dissolving polycaprolactone in a solvent may be applied as appropriate.

  The fiber-reinforced polycaprolactone in the present invention can be easily deformed with hot water or hot air. The temperature of the deformation process is 60 ° C. or higher, which is the melting point of polycaprolactone, generally about 60 to 120 ° C., and more preferably 60 to 100 ° C. The deformation can be, for example, bending, stretching, combinations thereof, and the like.

  In addition, since polycaprolactone has biodegradability, the entire fiber-reinforced polycaprolactone can be made biodegradable by using a natural fiber base material that is also biodegradable.

Hereinafter, the present invention will be described more specifically with reference to examples.
Examples 1-2
Preparation of a crosslinked polycaprolactone molded product Plaxel H5 (number average molecular weight 50,000, caprolactone manufactured by Daicel Chemical Industries, Ltd.) was completely melted at 100 ° C. and stirred with a vertical mixer, while perhexine 25B was added to 100 parts by weight of Plaxel H5. 1 part by weight of (2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3) (organic peroxide, manufactured by NOF Corporation, half-life at 150 ° C. for 1 hour) The mixture was kneaded for 15 minutes and then discharged to a tray. Thereafter, the mixture was heated to 80 ° C., and divided into 4 g pellets. A resin sheet having a thickness of 125 μm was molded at 80 ° C. using a press.

  Next, a glass fiber woven fabric having a mass of 202 g / m 2 and a Turkish satin weave texture (WPA15D103 manufactured by Nitto Boseki Co., Ltd.) was treated with γ-methacryloxypropyltrimethoxysilane in Example 1, and N- (2- Aminoethyl) -3-aminopropyltrimethoxysilane treatment, using this as a reinforcing fiber base material, and 8 glass fiber fabrics one by one between the 9 resin sheets, the outermost layer being a resin sheet And pressed at 130 ° C. for 30 minutes, and subsequently pressed at 150 ° C. for 120 minutes to produce a composite material. The gel amount when extracted in cyclohexanone at 100 ° C. for 24 hours was 90% in all cases. The glass fiber content in the composite material was measured as the ash content after the composite material was baked in an electric furnace at 900 ° C./1 hour. As a result, both Example 1 and Example 2 were 40% by weight.

Comparative Example 1
Preparation of non-crosslinked caprolactone fiber reinforced resin Plaxel H7 (number average molecular weight 70,000, caprolactone manufactured by Daicel Chemical Industries) was used to form 4 g of pellets in the same manner as in the Examples, and the thickness was 200 μm at 120 ° C. using a press. The resin sheet was molded.

  Next, a glass fiber fabric treated with γ-methacryloxypropyltrimethoxysilane (WPA15D103 manufactured by Nitto Boseki Co., Ltd.) is used as a reinforcing fiber base, and 7 glass fiber fabrics are placed between 8 resin sheets. Each sheet was sandwiched so that the outermost layer became a resin sheet and pressed at 150 ° C. for 90 minutes. The glass fiber content in the composite material was measured as an ash content after the composite material was baked in an electric furnace at 900 ° C./1 hour, and it was 50% by weight.

Each Example and Comparative Example were evaluated by the following evaluation methods. The results are shown in FIG.
Evaluation method: Dynamic viscoelasticity Measurement was performed by applying a sine strain of 1 Hz in a both-end bending mode using a viscoelasticity measuring apparatus DMS6100 manufactured by Seiko Instruments Inc. The measurement temperature range was 0 to 100 ° C., and the rate of temperature increase was 2 ° C./min.

  When caprolactone having a number average molecular weight of 70,000 was used, the molecular weight was too high, and when the glass fiber was impregnated, a high temperature of 150 ° C. and a long press were required. Further, in this case, melt kneading with an organic peroxide is impossible, and in this case, it has been found that an operation of dissolving in a solvent is necessary. Moreover, it became clear from an Example that the elasticity modulus of 10 GPa or more was obtained by fiber-reinforced polycaprolactone, and the practical use range expanded. Furthermore, it was confirmed that the fiber reinforced resin structure can be freely deformed because the crystal part of the matrix resin is melted by heating and the elastic modulus is rapidly lowered at about 60 ° C. or higher.

  Furthermore, the following was found from FIG. That is, tan δ at a temperature equal to or higher than the melting point of the crystal was reduced by crosslinking polycaprolactone. Actually, tan δ = 0.65 at 100 ° C. in Comparative Example 1 (non-crosslinked PCL-FRP), but in Examples 1-2 (crosslinked PCL-FRP), it is as low as 0.3-0.4. This is because the viscosity component of the viscoelastic body is reduced by the cross-linking, and it can be seen that even when the melting temperature of the crystal is exceeded, it is no longer liquid but gelled. This not only improves the moldability of the resin without flowing during heat molding, but also suppresses stickiness when the molded product is heated to the vicinity of the melting point to perform secondary processing, and the processability of the molded product is improved. It means that it has the outstanding characteristic that it can bring about an improvement.

  In addition, the degree of crosslinking of polycaprolactone can be controlled by the type and content of organic peroxide, molding conditions for heat and pressure molding, and the like. Therefore, by appropriately setting the molecular weight of polycaprolactone containing organic peroxide and the degree of crosslinking of polycaprolactone, the material properties and secondary processability of the fiber-reinforced polycaprolactone molded product should be set according to the required properties. Can do.

  The composite material of the present invention can be advantageously used for applications utilizing the above-mentioned properties, for example, various industrial materials, various molded products as prototype materials, for example, home appliances, sports equipment, building materials, toys, It can be used for play equipment, models, etc.

The graph which shows the change by the elastic modulus (E ') and tan-delta of the composite material obtained in Example 1, 2 and the comparative example 1 with temperature.

Claims (5)

Overlaying a polycaprolactone pellet material or sheet material containing an organic peroxide and a reinforcing fiber base material, heating and pressing, impregnating the reinforcing fiber base material with the polycaprolactone, and crosslinking the polycaprolactone. A method for producing a fiber-reinforced polycaprolactone, which is characterized. 2. The method for producing fiber-reinforced polycaprolactone according to claim 1, wherein the polycaprolactone pellet material or sheet material containing the organic peroxide has a number average molecular weight of 10,000 to 65,000. The fiber length of the reinforcing fiber of the said reinforcing fiber base material is 10 mm or more, The manufacturing method of the fiber reinforced polycaprolactone of Claim 1 or Claim 2. Polycaprolactone comprising a reinforcing fiber as a reinforcing material, crosslinked with polycaprolactone having a number average molecular weight of 10,000 or more, and having a gel content of 50% or more when extracted in cyclohexanone at 100 ° C. for 24 hours is used as a matrix resin. A fiber-reinforced polycaprolactone characterized by The fiber reinforced polycaprolactone according to claim 4, wherein the fiber length of the reinforcing fiber is 10 mm or more.

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