JP5604820B2 - Molded body and method for producing hollow molded body - Google Patents

Description

The present invention relates to a molded body and a method for producing a hollow molded body.

As a fuel tank for storing or transferring fuel such as gasoline, a metal tank has been conventionally used. However, in terms of weight reduction of the vehicle, rust prevention, workability to a desired shape, etc. Those made of a thermoplastic resin have been proposed. As such a resin container, an olefin-based resin such as polyethylene is used from the viewpoint of mechanical properties and economy.

However, when a container using an olefin-based resin such as polyethylene is used as a fuel tank used in an automobile or the like, there is a problem that gasoline penetrates the wall surface of these resins and is scattered in the atmosphere.

In order to solve this problem, it has been proposed to use PA (polyamide) resin or EVOH (ethylene vinyl alcohol copolymer) resin as a barrier layer.

For example, a pair of halves that are made by injection molding or compression molding or injection compression molding and have a film serving as a barrier layer for the fuel to be stored on their surfaces are joined with their opening edges abutted against each other. A resin fuel container is disclosed (for example, see Patent Document 1).

Further, in the automobile fuel tank formed of an inner resin layer and an outer resin layer made of a thermoplastic resin, the inner resin layer is divided into separately formed upper peripheral portions of the upper tank portion and the lower tank portion. An automobile fuel tank is disclosed in which the outer resin layer is integrally formed by covering the entire outer surface of the joined inner resin layer (see, for example, Patent Document 2). ).

And the molded article which has the interruption | blocking film insert-molded with the polymer material is disclosed (for example, refer patent document 3).

Japanese Patent Laid-Open No. 10-157738 JP 2006-160093 A JP-T-2004-504958

However, the conventionally proposed method has not been able to produce a molded article having excellent thickness uniformity, light weight, low fuel permeability, and excellent chemical resistance.
For example, in the methods described in Patent Document 1 and Patent Document 2, polyamide or ethylene vinyl alcohol copolymer is used as the barrier layer, but the biofuel resistance is not satisfactory. Further, in Patent Document 3, vinylidene fluoride is also exemplified as one of the materials constituting the barrier film. However, if only vinylidene fluoride is used as the barrier film, the fuel barrier property and low-temperature impact of the barrier film are only described. There is room for improvement in order to obtain a molded article that is not sufficient in performance and can be suitably used as a fuel tank or the like.

An object of the present invention is to provide a method for producing a molded article having excellent thickness uniformity and excellent weight reduction, low fuel permeability, chemical resistance, mechanical properties, and molding processability.

The present invention includes a step (1) of preforming a fluororesin film and a step (2) of injection-molding a polymer material, and the step (2) is a step of insert-molding the preformed fluororesin film. The fluororesin film is a method for producing a molded product characterized by including at least a fluororesin layer.

The present invention is also a method for manufacturing a hollow molded body, comprising a step of joining two molded bodies that are separately manufactured by the method for manufacturing a molded body.
The present invention is described in detail below.

The manufacturing method of the said molded object includes the process (1) of preforming a fluororesin film. Preliminary molding of the fluororesin film makes it difficult for wrinkles to occur during injection molding and eliminates defects between layers, thus improving the mechanical characteristics.

The pre-forming of the fluororesin film can be performed by vacuum forming, pressure forming, press forming or the like.

In the preliminary molding of the fluororesin film, molding conditions may be appropriately set according to the type, shape, application, etc. of the fluororesin used.

The manufacturing method of the said molded object includes the process (2) of injection-molding a polymer material, and this process (2) is a process of insert-molding the preformed fluororesin film.

According to the method for producing a molded body of the present invention, a layer formed by injection molding a polymer material (hereinafter also referred to as “polymer material layer”) without using an adhesive layer made of an adhesive or other material. And high adhesiveness with a fluororesin film can be obtained.

Moreover, since the injection molding can control the thickness of the molded article to be obtained, the fuel tank can be reduced in weight by setting the minimum thickness to obtain the required mechanical strength. Further, it is suitable for molding a molded body having a complicated shape, and can be particularly suitably used for molding a fuel tank, for example, and has excellent productivity.

The injection molding is preferably performed by, for example, injecting a polymer material into a mold and insert-molding a preformed fluororesin film installed in the mold. More specifically, it is preferable to produce a molded body having a fluororesin layer on its surface by injecting the molten polymer material into a mold having a pre-formed fluororesin film and solidifying it. .
The insert molding may be performed by integrating a preformed fluororesin film and a layer made of a polymer material.

The injection molding may be performed twice or more, but is usually performed once from the viewpoint of improving productivity and reducing costs. When performed twice or more, the polymer material layer formed of the polymer material may have a multilayer structure of two or more layers. When performing injection molding twice or more, the second and subsequent injection moldings need not be insert molding.

Each condition of the injection molding can be appropriately selected according to the type and amount of the polymer material to be used.
In the injection molding, from the viewpoint of improving the adhesion between the layers, it is also preferable to maintain the temperature at 220 to 300 ° C, preferably about 240 to 280 ° C after injecting the polymer material. By maintaining the temperature within the above range, the adhesion between the fluororesin layer and the polymer material layer can be further improved. The time maintained in the injection molding is preferably about 1 to 15 minutes.
In addition, the temperature maintained in the said injection molding is the temperature of a metal mold | die.

The polymer material may contain fluorine, but preferably does not contain fluorine. By not containing fluorine, mechanical properties are improved, which is advantageous in terms of cost.

The polymer material is preferably a thermoplastic resin or a thermosetting resin. More preferred is a thermoplastic resin. A thermoplastic resin is a polymer that exhibits plasticity when heated. By using a thermoplastic resin, it is possible to produce a molded article having excellent mechanical properties and molding processability.

Examples of the polymer material include polyolefin resin, polyamide resin, modified polyolefin resin, polyvinyl resin, polyester, ethylene / vinyl alcohol resin, polyacetal resin, polyurethane resin, polyphenylene oxide resin, polycarbonate resin, acrylic resin, styrene resin, Examples include acrylonitrile / butadiene / styrene resin [ABS], vinyl chloride resin, cellulose resin, polyetheretherketone resin [PEEK], polysulfone resin, polyethersulfone resin [PES], polyetherimide resin, and polyphenylene sulfide resin. . From the viewpoint of adhesion and low fuel permeability, ethylene / vinyl alcohol resin is preferred. In view of flexibility, adhesiveness, moldability, etc., at least one resin selected from the group consisting of polyamide resin, polyolefin resin and modified polyolefin resin is preferable.

The ethylene / vinyl alcohol resin is obtained by saponifying an ethylene / vinyl acetate copolymer obtained from ethylene and vinyl acetate. The blending ratio of ethylene and vinyl acetate to be copolymerized is appropriately determined according to the ratio of the number of moles of vinyl acetate units defined by the formula described later.

The ethylene / vinyl alcohol resin preferably has a vinyl acetate unit X mol% and a saponification degree Y% satisfying X × Y / 100 ≧ 7.
If X × Y / 100 <7, the interlayer adhesion may be insufficient. X × Y / 100 ≧ 10 is more preferable.
The value of X × Y / 100 is an index of the hydroxyl group content of the ethylene / vinyl alcohol resin, and the large value of X × Y / 100 is the hydroxyl value of the ethylene / vinyl alcohol resin. This means that the group content is high.
The hydroxyl group is a group that can participate in the adhesion between the layer made of the ethylene / vinyl alcohol resin and the counterpart material to be laminated. When the hydroxyl group content is high, the interlayer adhesion in the resulting component is improved. . In the present specification, the “partner material to be laminated” refers to a material laminated in contact.

The “vinyl acetate unit X mol%” means the number of moles of vinyl acetate derived from vinyl acetate units in the total number of moles of ethylene and vinyl acetate added [N] in the molecule of the ethylene / vinyl alcohol resin. N _i ], and the following formula X _i (%) = (N _i / N) × 100
It means the average value of the molar content X _i represented in. The vinyl acetate unit X mol% is a value obtained by measurement using infrared absorption spectroscopy [IR].

The “vinyl acetate unit” means a part of the molecular structure of the ethylene / vinyl alcohol resin and derived from vinyl acetate. The vinyl acetate unit may be saponified and have a hydroxyl group, or may be unsaponified and have an acetoxyl group.

The “degree of saponification” is a percentage representing the ratio of the number of saponified vinyl acetate units to the sum of the number of saponified vinyl acetate units and the number of unsaponified vinyl acetate units. The saponification degree is a value obtained by measurement using infrared absorption spectroscopy [IR].

Examples of the ethylene / vinyl alcohol resin in which X and Y satisfy the above formula include Eval F101 (Kuraray Co., Ltd., vinyl acetate unit X = 68.0 mol%; saponification degree Y = 95%; X × Y / 100 = 64.6), Mersen H6051 (manufactured by Tosoh Corporation, vinyl acetate unit X = 11.2 mol%; degree of saponification Y = 100%; X × Y / 100 = 11.2), Technolink K200 ( Commercial products such as Taoka Chemical Co., Ltd., vinyl acetate unit X = 11.2 mol%; degree of saponification Y = 85%; X × Y / 100 = 9.52), etc.

The ethylene / vinyl alcohol resin preferably has an MFR at 200 ° C. of 0.5 to 100 g / 10 min.
Even if the MFR is less than 0.5 g / 10 minutes or more than 100 g / 10 minutes, the difference between the melt viscosity of the ethylene / vinyl alcohol resin and the melt viscosity of the fluororesin becomes large. Unevenness may occur, which is not preferable. A preferred lower limit is 1 g / 10 minutes and a preferred upper limit is 50 g / 10 minutes.

The polyamide resin is made of a polymer having an amide bond [—NH—C (═O) —] as a repeating unit in the molecule.
As the polyamide resin, a so-called nylon resin composed of a polymer in which an amide bond in a molecule is bonded to an aliphatic structure or an alicyclic structure, or a polymer in which an amide bond in a molecule is bonded to an aromatic structure. Any of so-called aramid resins may be used.
The nylon resin is not particularly limited. For example, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66, nylon 66/12, nylon 46, metaxylylenediamine / adipic acid What consists of polymers, such as a copolymer, is mentioned, You may use combining 2 or more types from these.

The polyamide resin may be composed of a polymer in which a structure having no amide bond as a repeating unit is block-copolymerized or graft-copolymerized in a part of the molecule.
Examples of such polyamide resins include polyamide elastomers such as nylon 6 / polyester copolymer, nylon 6 / polyether copolymer, nylon 12 / polyester copolymer, and nylon 12 / polyether copolymer. And the like.
These polyamide-based elastomers are obtained by block copolymerization of nylon oligomers and polyester oligomers via ester bonds, or by block copolymerization of nylon oligomers and polyether oligomers via ether bonds. It is obtained. Examples of the polyester oligomer include polycaprolactone and polyethylene adipate, and examples of the polyether oligomer include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. As the polyamide elastomer, nylon 6 / polytetramethylene glycol copolymer and nylon 12 / polytetramethylene glycol copolymer are preferable.

The amine value of the polyamide resin may be 10 to 60 (equivalent / 10 ⁶ g). Moreover, a preferable minimum may be 15 (equivalent / 10 < ⁶ > g), a preferable upper limit may be 50 (equivalent / 10 < ⁶ > g), and a more preferable upper limit may be 35 (equivalent / 10 < ⁶ > g).
In the present specification, the amine value is a value obtained by dissolving 1 g of polyamide resin in 50 ml of m-cresol by heating and titrating with 1/10 N p-toluenesulfonic acid aqueous solution using thymol blue as an indicator. Yes, unless otherwise specified, means the amine value of the polyamide resin before lamination.

Examples of the polyolefin resin include propylene homopolymer, propylene-ethylene block copolymer, low density polyethylene, medium density polyethylene, high density polyethylene, and ultra high density polyethylene.

Examples of the modified polyolefin resin include propylene homopolymer, propylene-ethylene block copolymer, low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ultra-high-density polyethylene such as maleic acid-modified, epoxy-modified, or amine (NH ₂ ) Modified ones are mentioned.

The polymer material is particularly preferably a polyolefin resin or a modified polyolefin resin. The molded product obtained by the production method of the present invention is more excellent in mechanical properties, molding processability and cost because the polymer material is a polyolefin resin or a modified polyolefin resin.

As the polymer material, high density polyethylene (HDPE), epoxy-modified high-density polyethylene, or amine-modified high-density polyethylene is more preferable, and high-density polyethylene is more preferable.

The high density polyethylene preferably has a density of 945 to 970 kg / m ³ . More preferably, it is 945-965 kg / m < ³ >. If the density of the high-density polyethylene is within the above range, a molded product having more excellent mechanical properties can be obtained.

As said polymer material, only 1 type of the material mentioned above may be contained, and 2 or more types may be contained.

The fluororesin film includes at least a fluororesin layer. The fluororesin layer is made of a fluorine-containing polymer (fluororesin).
The fluororesin film may be a single layer or a laminate of two or more layers. When the fluororesin film is composed of two or more layers, all the layers constituting the fluororesin film may be fluororesin layers or include a layer not containing fluorine (a fluorine-free layer). Also good. When the fluorine-free layer is included, the layer constituting at least one surface of the fluororesin film is preferably a fluororesin layer. According to this, when manufacturing a hollow molded object using the molded object obtained by the manufacturing method of this invention, since the surface which contacts a fuel can be made into a fluororesin layer, it is preferable.

The fluororesin is not particularly limited as long as it is a melt-processable fluororesin, but is preferably a homopolymer or copolymer having a repeating unit derived from at least one fluorine-containing ethylenic monomer. .

The fluororesin may be obtained by polymerizing only a fluorine-containing ethylenic monomer, or by polymerizing a fluorine-containing ethylenic monomer and an ethylenic monomer having no fluorine atom. It may be a thing.

The fluororesin is tetrafluoroethylene [TFE], vinylidene fluoride, chlorotrifluoroethylene [CTFE], vinyl fluoride, hexafluoropropylene [HFP], hexafluoroisobutene, CH ₂ = CX ¹ (CF ₂ ). a monomer represented by _n X ² ( _where X ¹ is H or F, X ² is H, F or Cl, and n is an integer of 1 to 10), CF ₂ = CF-ORf ¹ (formula Rf ¹ represents a perfluoro (alkyl vinyl ether) [PAVE] represented by a C 1-8 perfluoroalkyl group, and CF ₂ = CF—OCH ₂ —Rf ² (wherein Rf ² is at least one of fluorine-containing ethylene are selected from the group consisting of alkyl perfluorovinyl ether derivative represented by a perfluoroalkyl group) having 1 to 5 carbon atoms Preferably has a repeating unit derived from the emission monomer.

Examples of the PAVE include perfluoro (methyl vinyl ether) [PMVE], perfluoro (ethyl vinyl ether) [PEVE], perfluoro (propyl vinyl ether) [PPVE], perfluoro (butyl vinyl ether), etc. Among them, PMVE PEVE or PPVE is more preferable.

As the alkyl perfluorovinyl ether derivative, those in which Rf ² is a perfluoroalkyl group having 1 to 3 carbon atoms are preferable, and CF ₂ = CF—OCH ₂ —CF ₂ CF ₃ is more preferable.

The fluororesin may have a repeating unit derived from an ethylenic monomer having no fluorine atom, and is an ethylenic monomer having 5 or less carbon atoms from the viewpoint of maintaining heat resistance and chemical resistance. Having a repeating unit derived from the body is also a preferred form. The fluororesin may have at least one fluorine-free ethylenic monomer selected from the group consisting of ethylene, propylene, 1-butene, 2-butene, vinyl chloride, vinylidene chloride and unsaturated carboxylic acid. preferable.

The unsaturated carboxylic acid has at least one carbon-carbon unsaturated bond that enables copolymerization, and one molecule of a carbonyloxy group [—C (═O) —O—]. Those having at least one are preferable, and may be an aliphatic unsaturated monocarboxylic acid, or may be an aliphatic unsaturated polycarboxylic acid having two or more carboxyl groups. / 100420 pamphlet as described in the unsaturated carboxylic acid.

Examples of the aliphatic unsaturated carboxylic acid include (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, mesaconic acid and aconite More preferably, it is at least one selected from the group consisting of acids.

Examples of the fluororesin include polychlorotrifluoroethylene [PCTFE], ethylene / tetrafluoroethylene copolymer [ETFE], chlorotrifluoroethylene / tetrafluoroethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer [ FEP], tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer [PFA], and polyvinylidene fluoride [PVdF], and preferably at least one selected from the group consisting of chlorotrifluoroethylene / More preferably, it is at least one fluororesin selected from the group consisting of a tetrafluoroethylene copolymer, FEP and PFA.

In the chlorotrifluoroethylene [CTFE] / tetrafluoroethylene [TFE] copolymer, the molar ratio of CTFE units to TFE units is preferably CTFE: TFE = 2: 98 to 98: 2, and 5:95. More preferably, it is -90: 10, and it is still more preferable that it is 20: 80-90: 10. If the number of CTFE units is too small, the low chemical liquid permeability tends to be deteriorated and the melt processing tends to be difficult. If too much, the heat resistance and chemical resistance during molding may be deteriorated.

The CTFE / TFE copolymer is preferably a copolymer comprising CTFE, TFE, and a monomer copolymerizable with CTFE and TFE. Monomers copolymerizable with CTFE and TFE include ethylene, VdF, HFP, CH ₂ = CX ¹ (CF ₂ ) _n X ² (wherein X ¹ is H or F, X ² is H, F or Cl, n is an integer of 1 to 10.), CF ₂ = CF-ORf ¹ (wherein Rf ¹ represents a perfluoroalkyl group having 1 to 8 carbon atoms). Perfluoro (alkyl vinyl ether) [PAVE] and CF ₂ = CF—OCH ₂ —Rf ⁵ (wherein Rf ⁵ represents a perfluoroalkyl group having 1 to ⁵ carbon atoms). Examples thereof include alkyl perfluorovinyl ether derivatives, among which at least one selected from the group consisting of ethylene, VdF, HFP and PAVE is preferable, and PAVE is more preferable.

The PAVE is selected from the group consisting of perfluoro (methyl vinyl ether) [PMVE], perfluoro (ethyl vinyl ether) [PEVE], perfluoro (propyl vinyl ether) [PPVE], and perfluoro (butyl vinyl ether). It is preferably at least one, and more preferably at least one selected from the group consisting of PMVE, PEVE and PPVE.

As the alkyl perfluorovinyl ether derivative, those in which Rf ⁵ is a perfluoroalkyl group having 1 to 3 carbon atoms are preferable, and CF ₂ = CF—OCH ₂ —CF ₂ CF ₃ is more preferable.

The CTFE / TFE copolymer has a monomer unit derived from CTFE and a monomer copolymerizable with TFE in an amount of 0.1 to 10 mol%, and a total of CTFE units and TFE units of 90 to 99.99. It is preferably 9 mol%. If the amount of copolymerizable monomer units is too small, the moldability, environmental stress crack resistance and stress crack resistance are likely to be inferior, and if too large, the chemical solution has low permeability, heat resistance, mechanical properties, productivity, etc. is there. The lower limit of the monomer unit derived from the monomer copolymerizable with CTFE and TFE is more preferably 0.5 mol%, and the upper limit is more preferably 5 mol%.

FEP can be particularly excellent in heat resistance, and is preferable in that excellent low fuel permeability is exhibited. Although it does not specifically limit as FEP, It is preferable that it is a copolymer which consists of 70-99 mol% of TFE units and 1-30 mol% of HFP units, 80-97 mol% of TFE units, and 3-20 mol% of HFP units. More preferably, it is a copolymer comprising If the TFE unit is less than 70 mol%, the mechanical properties tend to decrease, and if it exceeds 99 mol%, the melting point becomes too high and the moldability tends to decrease.

FEP may be a copolymer comprising TFE, HFP, and a monomer copolymerizable with TFE and HFP, and the monomer is exemplified as a monomer copolymerizable with CTFE and TFE. Monomer may be used. As the ^{_{monomer, CF 2 = CF-OR f}} 1 ( _{wherein, R} ^{f 1} represents. A perfluoroalkyl group having 1 to 5 carbon atoms) perfluoro (alkyl vinyl ether) represented by [PAVE] , CX ¹ X ² = CX ³ (CF ₂ ) _n X ⁴ (wherein X ¹ , X ² and X ³ are the same or different and represent a hydrogen atom or a fluorine atom, and X ⁴ represents a hydrogen atom, fluorine represents an atom or a chlorine atom, n represents a vinyl monomer represented by the representative.) the integer from 2 to 10, _{and, CF 2 = CF-OCH 2} -Rf 2 ( wherein, Rf ² is 1 to the number of carbon atoms 5 represents a perfluoroalkyl group, and the like. Among them, PAVE is preferable.

The PAVE is selected from the group consisting of perfluoro (methyl vinyl ether) [PMVE], perfluoro (ethyl vinyl ether) [PEVE], perfluoro (propyl vinyl ether) [PPVE], and perfluoro (butyl vinyl ether). It is preferably at least one, and more preferably at least one selected from the group consisting of PMVE, PEVE and PPVE.

As the alkyl perfluorovinyl ether derivative, those in which Rf ² is a perfluoroalkyl group having 1 to 3 carbon atoms are preferable, and CF ₂ = CF—OCH ₂ —CF ₂ CF ₃ is more preferable.

FEP has 0.1 to 10 mol% of monomer units derived from monomers copolymerizable with TFE and HFP, and 90 to 99.9 mol% of TFE units and HFP units in total. Is preferred. If the copolymerizable monomer unit is less than 0.1 mol%, the moldability, environmental stress crack resistance and stress crack resistance tend to be inferior, and if it exceeds 10 mol%, the chemical solution has low permeability, heat resistance, machine It tends to be inferior in characteristics and productivity.

PFA can be made particularly excellent in heat resistance, and is preferable in that it exhibits excellent low fuel permeability. Although it does not specifically limit as PFA, It is preferable that it is a copolymer which consists of 70-99 mol% of TFE units and 1-30 mol% of PAVE units, TFE units 80-98.5 mol%, and PAVE units 1.5. More preferably, the copolymer is composed of ˜20 mol%. If the TFE unit is less than 70 mol%, the mechanical properties tend to decrease, and if it exceeds 99 mol%, the melting point becomes too high and the moldability tends to decrease.

The PAVE is selected from the group consisting of perfluoro (methyl vinyl ether) [PMVE], perfluoro (ethyl vinyl ether) [PEVE], perfluoro (propyl vinyl ether) [PPVE], and perfluoro (butyl vinyl ether). It is preferably at least one, more preferably at least one selected from the group consisting of PMVE, PEVE and PPVE, and even more preferably PMVE.

The PFA may be a copolymer composed of TFE, PAVE, and a monomer copolymerizable with TFE and PAVE, and the monomer may be a copolymerizable with CTFE and TFE. The exemplified monomers may be used. As the monomer, HFP, CX ¹ X ² = CX ³ (CF ₂ ) _n X ⁴ (wherein X ¹ , X ² and X ³ are the same or different and represent a hydrogen atom or a fluorine atom, X ⁴ represents a hydrogen atom, a fluorine atom, or a chlorine atom, and n represents an integer of 2 to 10.), and CF ₂ = CF—OCH ₂ —Rf ² (wherein , Rf ² represents a perfluoroalkyl group having 1 to 5 carbon atoms.) And the like. Among them, PAVE is preferable.

As the alkyl perfluorovinyl ether derivative, those in which Rf ² is a perfluoroalkyl group having 1 to 3 carbon atoms are preferable, and CF ₂ = CF—OCH ₂ —CF ₂ CF ₃ is more preferable.

The PFA has a monomer unit derived from a monomer copolymerizable with TFE and PAVE in an amount of 0.1 to 10 mol%, and a total of TFE unit and PAVE unit is 90 to 99.9 mol%. It is preferable. If the copolymerizable monomer unit is less than 0.1 mol%, the moldability, environmental stress crack resistance and stress crack resistance tend to be inferior, and if it exceeds 10 mol%, the chemical solution has low permeability, heat resistance, machine It tends to be inferior in characteristics and productivity.

The ETFE is preferable in terms of improving mechanical properties and fuel barrier properties. The content molar ratio of the TFE unit to the ethylene unit is preferably 20:80 to 90:10, more preferably 37:63 to 85:15, and still more preferably 38:62 to 80:20.

The ETFE may be a copolymer composed of TFE, ethylene, and a monomer copolymerizable with TFE and ethylene. As the copolymerizable monomer, the following formulas CH ₂ = CX ⁵ R _f ³ , CF ₂ = CFR _f ³ , CF ₂ = CFOR _f ³ , CH ₂ = C (R _f ³ ) ₂
(Wherein, X ⁵ represents a hydrogen atom or a fluorine atom, and R _f ³ represents a fluoroalkyl group which may contain an etheric oxygen atom.)
Among them, a fluorine-containing vinyl monomer represented by CF ₂ = CFR _f ³ , CF ₂ = CFOR _f ³ and CH ₂ = CX ⁵ R _f ³ is preferable, and HFP, CF ₂ = CF-OR _f ⁴ (wherein R _f ⁴ represents a perfluoroalkyl group having 1 to 5 carbon atoms), and perfluoro (alkyl vinyl ether) [PAVE] and R _f ³ have 1 carbon atom. 8 is a fluoroalkyl group _CH 2 ⁼ CX ₅ fluorine-containing vinyl monomer represented by _R ^{f 3} is more preferable.

Specific examples of the fluorine-containing vinyl monomer represented by the above formula include 1,1-dihydroperfluoropropene-1, 1,1-dihydroperfluorobutene-1, 1,1,5-trihydroperfluoropentene-1. 1,1,7-trihydroperfluoroheptene-1,1,1,2-trihydroperfluorohexene-1,1,1,2-trihydroperfluorooctene-1,2,2,3 3,4,4,5,5-octafluoropentyl vinyl ether, perfluoro (methyl vinyl ether), perfluoro (propyl vinyl ether), hexafluoropropene, perfluorobutene-1, 3,3,3-trifluoro-2- (trifluoromethyl) propene -1,2,3,3,4,4,5,5- heptafluoro-1-pentene _(CH 2 = CFC ₂ CF ₂ CF ₂ H), and the like.

The monomer copolymerizable with TFE and ethylene may be an aliphatic unsaturated carboxylic acid such as itaconic acid or itaconic anhydride described above.

The monomer copolymerizable with TFE and ethylene is preferably from 0.1 to 10 mol%, more preferably from 0.1 to 5 mol%, particularly preferably from 0.2 to 4 mol%, based on the fluoropolymer. preferable.

The content of each monomer of the copolymer described above can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis depending on the type of monomer.

The fluororesin is preferably a perhalopolymer. By using a perhalopolymer, the fuel has low fuel permeability and excellent chemical resistance. The perhalopolymer is a polymer in which halogen atoms are bonded to all the carbon atoms constituting the main chain of the polymer.
The perhalopolymer is preferably at least one selected from the group consisting of the above-mentioned chlorotrifluoroethylene / tetrafluoroethylene copolymer, FEP and PFA.

The fluororesin preferably has 80 to 500 adhesive functional groups per 10 ⁶ main chain carbon atoms. When there are too many adhesive functional groups, a molded product having a smooth surface cannot be obtained, and there is a possibility that bubbles are easily contained inside the molded product. When there are too few adhesive functional groups, there exists a possibility that it may become difficult to adhere | attach with the layer formed from another material.

The adhesive functional group is preferably at least one selected from the group consisting of a carbonyl group, a hydroxyl group and an amino group. The adhesive functional group may be a functional group derived from a monomer having an adhesive functional group, or may be a functional group derived from a polymerization initiator.

The “carbonyl group” is a carbon divalent group composed of a carbon-oxygen double bond, and is represented by a group represented by —C (═O) —. The carbonyl group is not particularly limited. For example, a carbonate group, a carboxylic acid halide group (halogenoformyl group), a formyl group, a carboxyl group, an ester bond [—C (═O) O—], an acid anhydride bond [— C (═O) O—C (═O) —], isocyanate group, amide group, imide group [—C (═O) —NH—C (═O) —], urethane bond [—NH—C (= O) O—], carbamoyl group [NH ₂ —C (═O) —], carbamoyloxy group [NH ₂ —C (═O) O—], ureido group [NH ₂ —C (═O) —NH— ], oxamoyl group _{[NH 2 -C (= O) -C} (= O) - ] as such is part of the chemical structure of the like.

The carbonate group, -OC (= O) O- R 1 ( wherein, ^{R 1} represents. Alkyl group) is represented by. R ¹ is preferably an alkyl group having 1 to 20 carbon atoms or an alkyl group having 2 to 20 carbon atoms having an ether bond, and has 2 to 4 carbon atoms having an alkyl group having 1 to 8 carbon atoms or an ether bond. The alkyl group is more preferably. Examples of the carbonate group include —OC (═O) OCH ₃ , —OC (═O) OC ₃ H ₇ , —OC (═O) OC ₈ H ₁₇ , —OC (═O) OCH ₂ CH ₂ CH _2. Preferred examples include OCH ₂ CH _{3 and the} like.

A hydrogen atom bonded to a nitrogen atom such as an amide group, an imide group, a urethane bond, a carbamoyl group, a carbamoyloxy group, a ureido group, or an oxamoyl group may be substituted with a hydrocarbon group such as an alkyl group.

The above-mentioned adhesive functional group is easy to introduce, and the resin obtained has moderate heat resistance and good adhesion at a relatively low temperature, so that it has an amide group, carbamoyl group, hydroxyl group, carboxyl group. Group, carbonate group, and carboxylic acid halide group are preferable, and those having a carbonate group and / or a carboxylic acid halide group described in International Publication No. 99/45044 pamphlet are particularly preferable.

The number of the adhesive functional groups can be measured by the methods described in Japanese Patent Publication No. 37-3127 and International Publication No. 99/45044 pamphlet. For example, when an infrared absorption spectrum analysis of a fluoropolymer film sheet is performed using an infrared spectrophotometer and the number of functional groups is measured from an absorption band of a frequency specific to the functional group, for example, the —COF end is 1884 cm ^{− 1} absorption bands, -COOH ends are absorption bands of 1813 cm ^-1 and 1775 cm ^-1 , -COOCH ₃ ends are absorption bands of 1795 cm ^-1 , -CONH ₂ ends are absorption bands of 3438 cm ^-1 , -CH ₂ OH ends are The absorption band at 3648 cm ^−1, the —CF═CF ₂ end can be calculated from the absorption band at 1790 cm ⁻¹ .

When the fluororesin has an adhesive functional group, the fluororesin may consist of a polymer having the adhesive functional group at either the main chain end or the side chain, or the main chain end and side chain. It may consist of a polymer possessed in both. When the fluororesin has an adhesive functional group at the end of the main chain, it may have at both ends of the main chain or only at one of the ends. When the adhesive functional group has an ether bond, the adhesive functional group may have the adhesive functional group in the main chain.
The fluororesin is preferably composed of a polymer having an adhesive functional group at the end of the main chain because it does not significantly reduce mechanical properties and chemical resistance, or because it is advantageous in terms of productivity and cost.
As a method for introducing the adhesive functional group, a monomer containing the functional group as described above may be copolymerized or introduced as a polymerization initiator.

In the present invention, the fluororesin is not particularly limited, but the melting point is preferably 160 to 270 ° C.
The molecular weight of the fluororesin is preferably in a range where the obtained molded article can exhibit mechanical properties, chemical liquid permeability, and the like. For example, the MFR at an arbitrary temperature in the range of about 230 to 350 ° C., which is a general molding temperature range of a fluororesin, is preferably 0.5 to 100 g / 10 min using the melt flow rate [MFR] as an index of molecular weight. .
In this specification, melting | fusing point of each resin is calculated | required as temperature corresponding to the maximum value in a heat of fusion curve when it heats up at a speed | rate of 10 degree-C / min using a DSC apparatus (made by Seiko), MFR was measured using a melt indexer (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the weight (g) of the polymer flowing out in a unit time (10 minutes) from a nozzle having a diameter of 2 mm and a length of 8 mm under a load of 5 kg. Is.

The fluororesin preferably has a fuel permeability coefficient of 10 g · mm / m ² / day or less, more preferably 1 g · mm / m ² / day or less, and more preferably 0.5 g · mm / m ² / day. More preferably, it is as follows. The molded body obtained by the production method of the present invention can have a higher fuel low permeability because the fuel permeability coefficient of the fluororesin is within the above range.

In the present specification, the fuel permeation coefficient is 7.5: 7.5 with an isooctane / toluene / ethanol mixed solvent (hereinafter referred to as CE10) obtained by mixing isooctane, toluene and ethanol in a volume ratio of 45:45:10. A mixed solvent (hereinafter referred to as CE85) mixed at a volume ratio of 5:85 was calculated from the change in mass measured at 60 ° C. with the film obtained from the resin to be measured put in the fuel permeation coefficient measurement cup. The larger value of the two values to be used.

The fluororesin can be obtained by a conventionally known polymerization method such as suspension polymerization, solution polymerization, emulsion polymerization or bulk polymerization. In the above polymerization, the conditions such as temperature and pressure, the polymerization initiator and other additives can be appropriately set according to the composition and amount of the desired fluororesin.

The fluororesin film can be obtained by an ordinary molding method using the above-mentioned fluororesin, and the molding method is not particularly limited. For example, the method for producing the molded body may be a fluororesin film by extrusion molding. It is preferable from a viewpoint of production efficiency to include the process to obtain.

The fluororesin film may have an adhesive surface-treated surface from the viewpoint of improving interlayer adhesion and improving the mechanical properties of the resulting molded article. The adhesive surface treatment is not particularly limited, and examples thereof include known techniques such as etching treatment, plasma treatment, corona treatment, and photochemical treatment. The adhesive surface treatment can be performed by appropriately setting conditions according to the composition of the fluororesin used.

It is one of the preferable forms that the fluororesin film includes an organic material (however, excluding fluororesin) layer. According to this, the molded object obtained can include an organic material layer between the fluororesin layer and the polymer material layer.
When the fluororesin film includes an organic material layer, various characteristics obtained by the material constituting the organic material layer can be imparted to the molded body. For example, the organic material layer preferably functions as an adhesive layer that improves the adhesion between the fluororesin film and the polymer material layer formed from the polymer material.
When the fluororesin film consists only of a fluororesin layer, the adhesive between the fluororesin film and the polymer material layer may not be sufficient depending on the use of the molded product obtained by the production method of the present invention, the fluororesin used, the polymer material, etc. There is also. In such a case, by providing the organic material layer between the fluororesin layer and the polymer material layer, the adhesion can be improved, and a molded article having excellent mechanical properties can be obtained.

The organic material constituting the organic material layer (hereinafter also referred to as “organic material”) may be appropriately selected according to the type, shape, application, etc. of the obtained molded body. The material (however, excluding the fluororesin) may be used, and the material may be appropriately selected according to the purpose of providing the organic material layer. From the viewpoint of improving adhesiveness, it is preferably at least one of a polyamide resin and a modified polyolefin resin. The modified polyolefin resin is preferably a modified polyethylene.
The polyamide resin and the modified polyolefin are more preferable when the polymer material layer is a polyolefin resin, particularly high-density polyethylene.

The fluororesin film may have a two-layer structure of fluororesin layer / organic material layer, or a three-layer structure of fluororesin layer / first organic material layer / second organic material layer, It may be a four-layer structure of one fluororesin layer / second fluororesin layer / first organic material layer / second organic material layer (the first organic material layer and the second organic material layer are made of different organic materials) Organic material layer.) The structure of the fluororesin film is preferably, for example, a fluororesin layer / modified polyethylene resin layer / polyethylene resin layer, and the polyethylene resin layer is more preferably a layer made of high-density polyethylene. By having such a structure, the adhesiveness between the layers constituting the fluororesin film and between the fluororesin film and the polymer material layer is further improved.

In the case where the fluororesin film includes an organic material layer, the method for producing the fluororesin film is not particularly limited. For example, (i) the layers are thermally melt-bonded by coextrusion molding of the fluororesin and the organic material in a molten state. (Melt bonding) A method of forming a fluororesin film in one step (coextrusion molding), (ii) To form a film for forming a fluororesin layer separately produced by an extruder, and an organic material layer (Iii) Melting with an extruder on the surface of a film for forming a prefabricated fluororesin layer or a film for forming an organic material layer A method of forming a fluororesin film by extruding the prepared organic material or fluororesin, (iv) a film or an organic material layer for forming a prefabricated fluororesin layer After electrostatically coating organic material or fluororesin on the surface of the film to be formed, the material to be coated is heated and melted by heating the resulting coated product from the whole or from the painted side. And a method of forming the layer.

If the resin constituting each layer is coextrudable, it is preferably formed by coextrusion molding (i) above. Examples of the coextrusion molding include conventionally known multilayer co-extrusion manufacturing methods such as a multi-manifold method, a feed block method, a multilayer blow method, and a multilayer inflation molding method. By using these methods, a fluororesin film including a fluororesin layer and an organic material layer can be produced.

In the molding methods (ii) and (iii), after forming a film for forming each fluororesin layer and a film for forming an organic material layer, other layers in each film are formed for the purpose of improving interlayer adhesion. The contact surface with the film may be surface treated. Examples of such surface treatment include etching treatment such as sodium etching treatment; photochemical treatment using laser or excimer lamp; corona treatment; plasma treatment, etc. Among them, plasma treatment is preferable. The plasma treatment can be performed, for example, in an atmosphere of Ar, He, H ₂ , O ₂ , N ₂ , NH _{3, a} hydrocarbon gas, or a mixed gas thereof. Sufficient adhesive strength can be obtained by surface-treating the film.

As the molding method, a method of performing a surface treatment in each of the methods (i) and (ii) and (iii) above is preferable, and the method (i) is most preferable from the viewpoint of production efficiency.

It is one of the preferable forms that the manufacturing method of the molded object of this invention includes the process of apply | coating an adhesive agent on a fluororesin film. According to this, the obtained molded object will contain the adhesive bond layer which consists of an adhesive agent between a fluororesin film and a polymer material layer.
Depending on the use of the molded product obtained by the production method of the present invention, the fluororesin, the polymer material, etc., the adhesion between the fluororesin film and the polymer material layer may not be sufficient. In such a case, the adhesiveness between the fluororesin film and the polymer material layer can be improved by applying an adhesive on the fluororesin film.

The adhesive may be applied to a preformed fluororesin film, or may be applied to a fluororesin film before preforming, and then the fluororesin film is preformed.

The adhesive is not particularly limited, and is preferably one that can improve the adhesion between the fluororesin film and the polymer material layer than when the fluororesin film and the polymer material layer are directly adhered. For example, a cyanoacrylate adhesive, an epoxy adhesive, a rubber adhesive, an acrylic adhesive, an emulsion adhesive, or the like can be used.

As described above, the molded body obtained by the production method of the present invention is also one of preferable embodiments including an organic material layer and / or an adhesive layer between the fluororesin layer and the polymer material layer. The molded body may include both an organic material layer and an adhesive layer, and a plurality of each layer may be provided.

The materials constituting each of the above-described layers (fluorine resin layer, polymer material layer, organic material layer or adhesive layer) are further in the range not impairing the performance depending on the purpose and application, inorganic powder, glass fiber, metal oxide In addition to the filler, it may also be blended with other additives such as heat stabilizers, reinforcing agents, ultraviolet absorbers, pigments, etc. May be.
As the above additive, for example, in terms of reducing the permeation of chemicals, it is a smectite-based lamellar viscous mineral such as montmorillonite, beidellite, saponite, nontronite, hectorite, soconite, stevensite, etc., and a microlamellar having a high aspect ratio such as mica Minerals may be added.

As said additive, in order to provide electroconductivity, you may add a conductive filler, for example. The conductive filler is not particularly limited, and examples thereof include conductive simple powder such as metal and carbon or conductive simple fiber; powder of conductive compound such as zinc oxide; surface conductive powder.

The conductive single powder or conductive single fiber is not particularly limited, and examples thereof include metal powders such as copper and nickel; metal fibers such as iron and stainless steel; carbon black, carbon fiber, and Japanese Patent Laid-Open No. 3-174018. Examples of the carbon fibrils are listed.
The surface conductive treatment powder is a powder obtained by conducting a conductive treatment on the surface of a nonconductive powder such as glass beads or titanium oxide.

The method for conducting the conductive treatment is not particularly limited, and examples thereof include metal sputtering and electroless plating. Among the conductive fillers described above, carbon black is preferably used because it is advantageous in terms of economy and prevention of electrostatic charge accumulation. When blending the conductive filler, it is preferable to prepare pellets by melting and kneading in advance.

The volume resistivity of the material constituting each layer formed by blending the conductive filler is preferably 1 × 10 ⁰ to 1 × 10 ⁹ Ω · cm. A more preferred lower limit is 1 × 10 ² Ω · cm, and a more preferred upper limit is 1 × 10 ⁸ Ω · cm.
When imparting conductivity, conductivity may be imparted only to the fluororesin. In this case, the fluororesin layer may include both a fluororesin layer having conductivity and a fluororesin layer not having conductivity.

The molded body obtained by the production method of the present invention comprises at least two layers including a fluororesin layer and a polymer material layer made of a polymer material. If necessary, an organic material layer, an adhesive layer, or the like may be included between the fluororesin layer and the polymer material layer.

Examples of the structure of the molded body include a fluororesin layer / polymer material layer, a fluororesin layer / organic material layer / polymer material layer, a fluororesin layer / adhesive layer / polymer material layer, and a fluororesin layer / first organic material. Examples include a structure of layer / second organic material layer / polymer material layer (the first organic material layer and the second organic material layer are organic material layers made of different organic materials).
More specifically, fluorine resin layer / polymer material layer, fluorine resin layer / NH ₂ modified polyethylene resin layer / polymer material layer, fluorine resin layer / polyamide resin layer / maleic acid modified polyethylene resin layer / polymer material layer, fluorine resin Layer / polyamide resin layer / (ethylene / vinyl alcohol resin layer) / polymer material layer, fluorine resin layer / maleic anhydride modified polyethylene resin layer / polymer material layer, fluorine resin layer / epoxy modified polyethylene resin layer / polymer material layer, etc. A structure is preferred.
Although not preferable from the viewpoint of productivity, it is possible to provide another layer on the surface of the polymer material layer opposite to the side on which the fluororesin layer is provided in order to impart further characteristics. is there.

In addition to the above layers, pellets obtained by melting and kneading resin waste materials generated when processing multi-layer tanks and resins separated and recycled from multi-layer tanks with a twin screw extruder or single screw extruder Can be included as a recycling layer.

In the molded body, the fluororesin layer is preferably 50 to 500 μm, and the layers other than the fluororesin layer are preferably 100 to 50000 μm in total.
The preferable film thickness of the said fluororesin layer is 100-300 micrometers, and the preferable film thickness of layers other than a fluororesin layer is 300-20000 micrometers in total, More preferably, it is 900-10000 micrometers.
The said molded object can select the magnitude | size according to the use.
In this specification, the film thickness of each layer is measured with a microscope or the like.

The molded body obtained by the production method of the present invention can be suitably used for the production of a hollow molded body. Examples of the hollow molded body include fuel tanks such as automobile gasoline tanks and light oil tanks; radiator tanks; solvent tanks; paint tanks; chemicals with strong corrosive and erosive chemicals such as acids and alkalis such as chemicals for semiconductors. Containers and containers for abrasive slurry; bottles, containers, tanks, bags, underground buried tubes or hoses used for refueling stations, such as beverage or food and drink tanks. Further, the molded article, even as a container for the urea water in the system to reduce the NO _X by spraying urea water into exhaust gas from a diesel engine, can be suitably used to its excellent chemical resistance.
Among these, because of its excellent mechanical properties, chemical resistance, etc., it can be used particularly suitably for fuel tanks such as automobile gasoline tanks and light oil tanks.

The present invention is also a method for manufacturing a fuel tank of a hollow molded body including a step of joining two or three or more molded bodies that are separately manufactured by the method for manufacturing a molded body.
When manufacturing a hollow molded body such as a fuel tank, it is necessary to remove the mold after injection molding, so a hollow molded body cannot be created by a single injection molding, and a plurality of molded bodies are manufactured, Then, a desired hollow molded object can be obtained by joining integrally by means, such as heat sealing | fusion and adhesion | attachment.

In the present specification, the term “joining” means that the molded bodies are bonded to such an extent that fuel leakage does not occur at the joint by using heat fusion or an adhesive.

The molded bodies can be joined by, for example, melting the peripheral portions of the molded bodies with a hot plate and thermally welding them together (hereinafter also referred to as “hot melt bonding”). The melting by the hot plate can be selected according to the layer structure of the molded body to be used, but it should be performed at a temperature not lower than the melting point of the fluororesin and polymer material to be bonded and not higher than the thermal decomposition temperature of the fluororesin and polymer material. preferable. In addition, other conditions for the above-described heat welding can be appropriately set according to the layer structure of the molded body to be used.
In the case where an organic material layer is provided on the molded body, the temperature is preferably equal to or higher than the melting point of the organic material constituting the organic material layer.

Examples of the hot melt bonding include a method using a hot platen, a method using hot air, a method using frictional heat (mechanical and ultrasonic), and a method using high frequency.
The above-described hot melt bonding methods may be performed in combination.

When performing the manufacturing method of the said molded object and the manufacturing method of the said hollow molded object continuously, it is normally heated in manufacture of a molded object. In order to stabilize the molding, the manufactured molded body may be cooled once and then hot melt bonded. However, from the viewpoint of productivity, the hot melt bonded immediately after the molded body to be used is manufactured. It is preferable to carry out. It should be noted that electrofusion (electric fusion bonding) using a heating wire for the welded portion can also be used as the hot melt bonding.

Moreover, the method of utilizing an adhesive agent is also mentioned as said joining. In this case, for example, an adhesive is applied to the seam, pressed together and the adhesive is at least partially cured. Subsequently, after leaving it in an environment of 135 to 150 ° C., the joint is cooled under pressure. Complete curing of this seam requires 5-8 days at room temperature.

In the joining, it is preferable that two or three or more molded bodies produced separately are joined so that the fluororesin layer becomes the innermost layer. By using the fluororesin layer as the innermost layer, when the hollow molded body is used in a fuel tank or the like, the fuel has low fuel permeability.

In the joining, it is preferable that two or three or more molded bodies produced separately are joined at least with the fluororesin layers. According to this, since the joint part of the hollow molded body is a fluororesin, the low fuel permeability and chemical resistance of the entire hollow molded body can be maintained without impairing the fuel permeability of the joint part.

In the above-mentioned joining, it is preferable to join two or three or more molded bodies produced separately at least with the fluororesin layers, but it is also one of the preferred forms that the polymer material layers are joined together. is there. According to this, it can be set as the hollow molded object which is more excellent in mechanical strength.

In order to facilitate joining of the layers, at least a part of the ends of the molded bodies to be joined may be processed in advance as shown in FIG.

Hereinafter, the aspect of the process example of the edge of each molded object joined is demonstrated using FIG. FIG. 1 is an example of a mode in which the ends of the molded bodies to be joined are processed in advance. 3 is a polymer material layer, 4 is an organic material layer, and 5 is a fluororesin layer. By processing the end of the molded body 1 before processing like the molded body 2 after processing, the layers can be easily joined to each other.

Since the manufacturing method of the hollow molded body of the present invention consists of joining a plurality of molded bodies, for example, it is performed with a simpler apparatus than the manufacturing method by blow molding in which the hollow molded body is molded in one step. Therefore, it is possible to reduce the capital investment, and it is possible to easily manufacture a fuel tank having high dimensional accuracy and excellent strength even if it has a complicated shape.

The hollow molded body obtained by the above production method comprises at least two layers including a fluororesin layer and a polymer material layer. If necessary, an organic material layer, an adhesive layer, or the like may be included between the fluororesin layer and the polymer material layer. Moreover, you may have the layer structure of the molded object mentioned above.

The innermost layer of the hollow molded body is preferably a fluororesin layer. As described above, by disposing the fluororesin layer in the innermost layer, fuel such as gasoline comes into contact with the fluororesin layer, so that permeation can be suppressed. The outermost layer of the hollow molded body is preferably a polymer material, and the polymer material is preferably high-density polyethylene. High-density polyethylene has a high strength, so it is a lightweight and sturdy fuel tank.

Fuel permeation rate of the hollow molded body, the lower limit for example, be a 0.05g ^/ m 2 ^/ day, the upper limit for example, be a ^30g / m 2 / day.

In the present specification, the fuel permeation rate of the hollow molded body is the mass of the chemical liquid that permeates from the entire molded body per unit days and per unit area, and the permeation amount at 60 ° C. using CE10 or CE85. Is a value that can be measured.

The thickness of each layer such as the fluororesin layer and the polymer material layer in the hollow molded body is the same as that described for the method for producing the molded body of the present invention.

The hollow molded body is obtained by decomposing and dissolving a polymer material not containing fluorine by combining appropriate treatments such as high-temperature treatment and high-pressure treatment in the presence of water vapor or solvent even when the automobile is discarded. It is also possible to take out only the fluororesin and recycle it.

Since the hollow molded body obtained by the production method of the present invention is integrated by joining the molded body obtained by the above-mentioned molded body production method, it has excellent strength and low fuel permeability. In addition, by making the fluororesin layer the innermost layer, in addition to low fuel permeability, it is excellent in gasoline resistance. Therefore, the laminated structure can be simplified and the cost can be reduced. Furthermore, the said hollow molded object also has the advantage that there is no location in which a barrier layer does not exist also in a junction part by joining the fluororesin layers used as a barrier layer. Furthermore, since the molded body constituting the hollow molded body can be easily manufactured by injection molding, it is preferable in productivity and the like.

The molded body and the hollow molded body obtained by the production method of the present invention are excellent in thickness uniformity and excellent in weight reduction, fuel permeability, chemical resistance, and mechanical characteristics. In addition, a complicated layer structure is not required, and it can be easily manufactured.

FIG. 1 is an example of a mode in which the ends of the molded bodies to be joined are processed in advance.

Next, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to such examples.

Example Extrusion of a total of 3 units of 2 40φ extruders and 1 50φ extruder using fluororesin A, modified polyethylene (manufactured by Arkema, LOTADAR ADX1200) and high density polyethylene (manufactured by Nippon Polyethylene Co., Ltd., HB120) A multilayer film having a width of 45 cm and a thickness (fluororesin A / modified polyethylene / high-density polyethylene = 150 μm / 50 μm / 100 μm, total thickness 300 μm) was molded using a three-type three-layer multilayer film molding machine equipped with a machine.
The multilayer film is placed so that the high-density polyethylene layer is on the mold side, and is preliminarily used with a vacuum molding machine using an elliptical mold having a major axis of 250 mm, a minor axis of 200 mm, a depth of 50 mm, and a corner R of 10 mm. Molding was performed. The preforming was performed using a heater at 300 ° C. to 350 ° C., and the surface temperature of the multilayer film was 250 ° C.

The preformed multilayer film is fixed to the movable mold of the 80-ton injection molding machine so that the fluororesin layer is on the movable mold side, and after closing the mold, the cylinder temperature is 200 to 240 ° C., the mold temperature High-density polyethylene (manufactured by Nippon Polyethylene Co., Ltd., HB120) was injected at 80 ° C. to produce two molded products on one side of the tank. Thereafter, the welded portions of the molded product on one side of the tank are simultaneously heated with a hot plate above the melting point of the fluororesin A, and then welded to form a tank shape in which the innermost layer is made of fluororesin A and the outermost layer is made of high-density polyethylene. A molded product was obtained. The fuel permeation rate of the tank-shaped molded product was 0.45 g / m ² / day. The fuel permeation rate is the mass of the chemical that permeates from the entire molded body per unit days and per unit area, and is a value obtained by measuring the permeation amount at 60 ° C. using CE10.

In the examples, the following fluororesins were used.
[Fluororesin A (CTFE copolymer)]
(Synthesis method)
50 kg of demineralized pure water was charged in a jacketed stirring polymerization tank capable of containing 175 kg of water, the interior space was sufficiently replaced with pure nitrogen gas, and then the nitrogen gas was removed in vacuum. Next, 40.5 kg of octafluorocyclobutane, 2.4 kg of chlorotrifluoroethylene [CTFE], 6.5 kg of tetrafluoroethylene [TFE] and 4.5 kg of perfluoro (propyl vinyl ether) [PPVE] were injected and the temperature was adjusted to 35 ° C. Adjust and start stirring. Polymerization was started by adding 0.2 kg of a 50 mass% methanol solution of di-n-propyl peroxydicarbonate [NPP] as a polymerization initiator. During the polymerization, a mixed monomer prepared to have the same composition as the desired copolymer composition is polymerized while additionally charging so that the pressure in the tank is maintained at 0.8 MPa, and then the residual gas in the tank is exhausted. The produced polymer was taken out, washed with demineralized pure water, and dried to obtain 19 kg of a granular powder CTFE copolymer. Next, melt kneading was performed at a cylinder temperature of 280 ° C. using a φ50 mm single screw extruder to obtain pellets. Next, the obtained pellet-like CTFE copolymer was heated at 180 ° C. for 24 hours.

The obtained pellets had the following composition and physical properties.
CTFE / TFE / PPVE: 34.5 / 63.4 / 2.1 (mol%)
Melting point: 230 ° C
MFR: 18 g / 10 min (measured at 297 ° C.-load 5 kg)
Functional group: carbonate group (100 carbonates number to the main chain carbon 10 ⁶⁾
Fuel permeation coefficient: 0.3 g · mm / m ² / day

The molded body and the hollow molded body obtained by the production method of the present invention are excellent in uniformity of wall thickness, light weight, fuel permeability, chemical resistance, and mechanical characteristics, so that fuel for storing gasoline or the like It can be suitably used as a tank.

1: Molded body before processing 2: Molded body after processing 3: Polymer material layer 4: Organic material layer 5: Fluorine resin layer

Claims (5)

Including a step (1) of preforming a fluororesin film, and a step (2) of injection-molding a polymer material,
The step (2) is a step of insert molding a preformed fluororesin film,
Fluororesin film, looking contains at least fluorine resin layer and the organic material (excluding the fluororesin.) Layer,
The fluororesin constituting the fluororesin layer has 80 to 500 adhesive functional groups per 10 ⁶ main chain carbon atoms ,
The method for producing a molded article, wherein the organic material constituting the organic material layer is at least one of a polyamide resin and a modified polyolefin resin . The process for producing a molded article of claim 1, wherein further comprising the step of applying an adhesive onto the fluororesin film. The method for producing a molded article according to claim 1 or 2 , wherein the polymer material is high-density polyethylene. The fluororesin layer is at least one selected from the group consisting of a chlorotrifluoroethylene polymer, a tetrafluoroethylene / hexafluoropropylene copolymer, and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer. It consists of a fluororesin, The manufacturing method of the molded object of Claim 1, 2, or 3 characterized by the above-mentioned. A method for producing a hollow molded body comprising the step of joining two or more molded bodies produced separately by the method for producing a molded body according to claim 1, 2, 3 or 4 .

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