WO2000017057A1 - Blow-molded container - Google Patents

Abstract

A large blow-molded container having a smooth inner surface and an even wall thickness and usable for storage/transportation of high-purity liquid chemicals; and a blow molding material comprising a tetrafluoroethylene copolymer having a melting point of 230 °C or lower. The container is obtained by blow-molding the molding material comprising the melt-moldable fluororesin having (A) a melt flow rate at 230 °C of 0.1 to 20 g/10 min, (B) a melt tension at 190 to 260 °C of 2 to 50 gf, and (C) a concentration of fluorine ions released at 190 to 260 °C of 10 ppm or lower.

Description

 Akira Itoda blow molded container

Technical field

 INDUSTRIAL APPLICABILITY The present invention is a blow molding container having a smooth inner surface suitable for storing and transporting a high-purity chemical solution, and a melt molding particularly suitable as a material for low-temperature blow molding of the container. The present invention relates to a molding material comprising a low melting point fluorine-containing resin mainly composed of possible tetrafluoroethylene. Background art

 In the field of semiconductor manufacturing, miniaturization, high integration, and large scale are being strongly promoted, but in order to increase the product yield, dust (fine particles) must be used in the manufacturing process. ) And contamination of impurities must be minimized.

There are many risks of contamination by dust impurities in the semiconductor manufacturing process, and one of them is the contamination of chemicals. Many and many chemicals are used in the manufacture of semiconductors. For example, in the process of laminating semiconductors, acetate, trichloride, ethylene, methyl, isopropyl alcohol, acetic acid, butyl acetate, Organic solvents such as sulfuric acid, sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, ammonia water, hydrogen peroxide water, ammonium fluoride: ammonia, phosphorus Inorganic chemicals such as acid and buffered hydrofluoric acid are prepared as needed, and if necessary, surfactants and the like are added. Used as resist stripping and etching solution. If these chemicals are contaminated, they will be Even if the environment is clean, the product will be contaminated. Chemical contamination may occur during the chemical manufacturing process or during storage and transport of the chemical. Of these, chemicals are usually stored and transported by using chemical resin containers made of synthetic resin, which not only contaminates the chemicals at the time of injection, but also adds to the chemicals containers themselves. Pollution is also a significant factor.

 The performance required for such a chemical solution container is, for example, such as the following.

 (1) Material side: (1) It has a wide chemical resistance to various chemicals such as strong acids, strong alkalines and surfactants, and has no deterioration over time.

 (2) An impurity (especially metal), anion, etc. from the container itself must not be dissolved.

 (2) Manufacturing side: No contaminants adhere during the manufacturing stage.

 (3) Shape surface: The inner surface of the container must be smooth and free of fine particles (for example, particles having a particle size of about 0.1 m).

Among these required performances, fluororesin and polyethylene are currently used in terms of material, but in terms of chemical resistance, fluorine-containing resin is used. Some attention has been paid to the resin. Examples of fluorine-containing resins include tetrafluoroethylene copolymer (alkyl vinyl ether) copolymer (PFA) and tetrafluoroethylene copolymer. Pyrene copolymer (FEP), Ethylene Z tetrafluoroethylene copolymer (ETFE), Tetrafluoroethylene-Fluoro (vinyl vinyl acetate) (Tel) Z-hexafluoropropylene copolymers and other fluorine-containing resins that can be melt-molded have been studied and some have been put into practical use. From the manufacturing perspective, the rotating (rot molding) method, the welding sheet-lining method, and the blow molding method are used. However, in the case of the roto-molding method, the cycle time required for molding is long, and the powder adheres to the mold for a long time, so that metal components may be mixed. In addition, since the powder is solidified through the process of melting and cooling under no load, there is a problem in that the smoothness of the inner surface cannot be obtained, and the welding sheeter has a problem. In the inking method, there is a problem that it is impossible to form a small and narrow container, and there is a problem that the sheet is contaminated during welding work.

 In this respect, the blow molding method is a series of continuous processes, the cycle time required for molding is short, and the materials, atmosphere, and blow of the molding machine and mold are small. With strict air management, pollution can be significantly reduced. The surface smoothness is as good as that of an extruded sheet, making it the most suitable method for molding highly purified chemical liquid containers. Here, the blow molding method refers to a method in which a thermoplastic resin is melted and extruded from top to bottom, and the extruded parison is not cooled. And insert air into the mold. This is a molding method in which the mold is brought into close contact with the inner wall of the mold, cooled, solidified, and then taken out as a molded product.

 Polyethylene containers can be blow-molded into large containers exceeding 200 liter capacity, but they are used in semiconductor lamination processes. High-purity chemicals containing surfactants Inferior in chemical resistance, such as easy generation of cracks against nitric acid, hydrofluoric acid, and hydrofluoric acid The contamination resistance is also insufficient.

Therefore, it has been desired to use the fluorine-containing resin as a material for blow molding, as described above. However, when a fluorine-containing resin that can be melt-molded is used as the molding material, the density of the conventional fluorine-containing resin is large, unlike a general thermoplastic resin, and the density is high. Due to the severe nature of the chemicals, a chemical container that satisfies the above performance cannot be manufactured by a small container with a capacity of at most 15 liters or by the blow molding method. Was

 In addition, not only in blow molding, but also when using these fluorine-containing resins for molding, high corrosion-resistant metallic materials such as screws, cylinders, dies, etc. For example, Hastelloy (Ni group /

Special molding machines using such materials as Cτ / Mo alloy) and Halloy (Ni-based ZCo alloy, Cr or Ni-plated steel plate) are required. This is because when a fluororesin is melt-molded, corrosive gas (hydrofluoric acid) is generated by decomposition because the molding temperature and decomposition temperature are close to each other, and This is because general-purpose molding machines that use ordinary metallic materials, such as rest steel, cannot be used due to corrosion.

 An object of the present invention is to provide a novel blow molding material made of a low-melting fluorine-containing resin capable of manufacturing a large container.

 The present invention also provides a low-melting-point fluorocarbon resin that does not corrode ordinary metal materials during melt molding, and thus can be molded into a single piece using a general-purpose plastic molding machine. An object of the present invention is to provide a molding material, and a container obtained by blow molding using the molding material. Disclosure of the invention

The present invention comprises a melt-moldable fluororesin having a melting point of 230 ° C or lower, and (A) melt flow at 230 ° C. Over preparative is 0. Ri Ah at l ~ 2 0 g, 1 0 minutes, (B) 1 9 0 ~ 2 6 0. Menu Le to manual down in good or to rather is ^{2 0 0 ~ 2 4 0 D} C The cation is 2 to 50 gf, and (C) 190 to 260: preferably, the fluorine ion at 200 to 24 Ot: Relating to blow molding materials having a concentration of 10 ppm or less.

 The present invention also provides a container suitable for storing and transporting a high-purity chemical obtained by low-temperature blow molding using a molding material comprising such a fluorine-containing resin, particularly A container having an inner surface having a surface roughness Ra (central average roughness) of 0.07 / m or less, preferably 0.05 / zm or less, and more preferably For large containers with a capacity of more than 20 liters. The fluorine-containing resin is preferably a fluorine-containing copolymer containing 30 to 90 mol% of tetrafluoroethylene (TFE) units. In addition, those in which the unstable group at the terminal of the molecule is stabilized are preferably used. In addition, the blow molded container of the present invention has a multi-layered structure in which a layer obtained by blow molding a molding material made of such a fluorine-containing resin is the innermost layer. It can be a sealed container.

 The present invention further relates to a container having an inner capacity of 20 liters or more, which is manufactured by molding using a molding material comprising the above-mentioned fluororesin. Therefore, the minimum thickness of the container is 0.1 mm or more, and the surface roughness Ra (centerline average roughness) of the inner surface of the container is 0.07; ^ m or less. Particularly, the present invention relates to a blow molded container suitable as a container for a high-purity chemical solution. Such a preformed container preferably has a difference in wall thickness of the container wall of not more than 60%. Furthermore, the container can also produce a large container having a height ratio to the maximum outer diameter of 1 or more.

The present invention also relates to the container containing the high-purity chemical, and a method of using the container for storing and transporting the high-purity chemical. You Best Mode for Carrying Out the Invention The molding material of the present invention includes the above-mentioned specific melt-in-one-rate (A), melt-tension (B), It has a specific defluoridated ion concentration (C).

 The melting point of the present invention is 230, and the following fluorine-containing resins have a tetrafluoro port:!: Styrene (TFE) as low as 30 to 90 mol%. Fluorine-containing copolymers comprising at least 70 to 10 mol% of at least one other monomer are preferred.

 Such fluorine-containing copolymers include, for example, but are not limited to, but are not limited to, those of the type described above.

 (1) A copolymer in which another monomer contains at least one α-age refin.

 α-olefins include, for example, ethylene, propylene, 1-butene, etc., and in terms of strength, ethylene. Is preferred.

 In the case of using ethylene, from the point of view of the improvement of the cracking property, it is necessary to include at least one vinyl compound having 2 to 12 carbon atoms other than TFE and ethylene, and a ternary or higher. It is preferable to use a copolymer of

Examples of the above-mentioned vinyl compounds include perfluoroolefins such as hexafluoropropene (HFP), vinylidene fluoride (vinylidene fluoride), and the like. V d F), black mouth trifluoroethylene (CTFE), fluoroalkyl vinyl ether, CH ₂ = CF (CF ₂ ) _n H (n is an integer from 2 to 10) ), Etc. are required. These vinyl compounds As a copolymer when a product is used, a TFE ethylenno HFP copolymer is preferred from the viewpoint of reactivity, thermal stability and chemical resistance. The copolymer composition (molar% ratio) of the TFEZ ethylene HFP copolymer is 30 to 70/20 to 6555 to 30, preferably 30 to 602. 5-6 0 Roh 1 0-2 5, good or was rather, especially in Ru Oh in 3 5-6 0 / ^/ 2 5 to 5 0 1 0 to 2 0.

 (2) A copolymer in which the other monomer is fluoroalkyl vinyl ether.

 Among fluoroalkyl vinyl ethers, the copolymer resin with perfluoro (alkyl vinyl ether) is usually called PFA and has a high melting point (28%). 0 to 315 X:), but in the present invention, those having a melting point of 230 or less are used. For example, the melting point of a TFE / PMVE copolymer having a perfluoro (methyl vinyl ether) (PMVE) content of 12.7 mol% is about 221.

 (3) Another monomer is vinylidene fluoride (VdF), and furthermore, HFP or cross-port trifluorene (CTFE) A terpolymer containing.

 As specific examples, TFEZV d FZHFP ^ S 0 to 60 no 30 to 60 Z 5 to 15 (mole% ratio) or TFEZV d F / CTFE = 30 to 60/30 to 30 6 0 5 to 1 5

(Mol% ratio).

 (4) A TFEZHFP binary copolymer in which the other monomer is HFP.

 The fluorine-containing copolymer containing 14 to 20 mol% of HFP is preferable in terms of lowering the melting temperature.

Of the above (1) to (4), the TFE / ethylene ZHFP-based copolymers are most preferred in terms of heat resistance, container strength, thermal stability, and chemical resistance.

 As a general method for producing the above-mentioned fluorine-containing resin, industrially, a fluorine-based solvent is used, and an aqueous medium using an organic peroxide as a polymerization initiator is used. The suspension polymerization in the reaction is preferred, but it can be produced by other polymerization methods such as bulk, solution, suspension, emulsification, and gas phase polymerization.

As the fluorine-based solvent, there may be mentioned, for example, CH ₃ CC 1 F ₂ , CH 3 CC 1 ₂ FCF 3 CF 2 CC 1 ₂ H, CF ₂ C 1 CF ₂ CFHC 1), perfluoroalkanes (for example, no. 1 fluorocyclobutane, CF ₃ CF ₂ CF 2 CF 3 , CF 3 CF ₂ CF ₂ CF ₂ CF ₃ , CF ₃ CF ₂ CF 2 CF 2 CF 2 CF 3) can be used. Fluoroalkanes are preferred.

 The amount of the solvent to be used is preferably 10 to 100% by weight with respect to water from the viewpoint of suspendability and economy.

 Examples of the organic peroxide which is a polymerization initiator include diisopropyl peroxyside, diisopropyl peroxy dicarbonate, and di-n-propyl peroxy. High-carbon organic peroxides such as sigma-carbonate are removed. In addition, the formula:

(XC _p F _{2 p} CO 0) 2 (1)

 (Wherein, X is a hydrogen atom, a fluorine atom or a chlorine atom, and p is an integer of 2 to 8).

Specific examples of the organic peroxide (1) include zipper fluoropropionyl peroxide, di (ω-hydrofluorofluorohexanol), Oxyside, di (ω-black mouth perfloor hexanoyl) peroxyde, etc. The polymerization temperature is not particularly limited, but may be 0 to 100 ° C. industrially.

 The polymerization pressure may be generally 0 to 50 kgf Zcm 2 G, and a relatively low pressure of 1 to 20 kgf Zcm 2 G is desired for the polymerization operation, and a relatively low pressure. Power is also good for safety. The polymerization pressure is appropriately determined according to other polymerization conditions such as the type and amount of the solvent to be used, the vapor pressure, and the polymerization temperature.

 In the production of such a fluorine-containing copolymer, a conventional chain transfer agent, for example, isopentane, n-pentane, or n- is used to adjust the molecular weight. It is possible to use xanthane, cyclohexane, methanol, ethanol, carbon tetrachloride, mouth mouth foam, methylene chloride, methyl chloride, etc. it can .

 Further, in the molding material of the present invention, two or more kinds of low melting point fluorine-containing resins having different properties may be blended. For example, the melt flow rate (A) at 230 ° C is 10 to 100 g / 100 minutes, and the melt flow rate is 190 to 260 minutes. The TFE copolymer having a tension (B) of less than 5 gf has a melt flow rate (A) of 0.001 to 3.0 OgZlO in 230. The method of blending a TFE-based copolymer with a melt tension (で) of 10 gf or more in the range of 190 to 260 ° C./min. . The blend may be mixed and kneaded in the form of pellets, powder, or dispersion.

 In the above TFE-based copolymer, one C C H or _CH 2 ― H, -C OO, which depends on the polymerization initiator or molecular weight modifier used,

In some cases, terminal groups such as CH 3 remain, and these unstable terminal groups are thermally decomposed during melt molding to become one COF, and this —COF comes into contact with the chemical solution. When dissolved, it dissolves as a fluorine ion. Therefore, as a molding material for a chemical solution container, It is desirable to use those that have stabilized unstable terminal groups. As a method for stabilizing an unstable terminal group, a conventionally known method can be used. For example, treatment with fluorine gas (F 2) or ammonia gas to remove the end groups —CF ₃ or —CON

There are various methods such as heating to H 2, heating in the presence of steam or treating with hydrogen (H ₂ ) to CF 2 H. In the case of the present invention, since the container is formed by the blow molding method, the gas containing fluorine gas is used as the gas to be blown, and the container is formed by using a gas containing fluorine gas. At the same time as the molding, the unstable terminal groups in the TFE-based copolymer constituting the inner surface layer of the blow-molded container can be stabilized.

 The blow molding material of the present invention has (A) a melt flow rate at 230 ° C. of 0.:! To 20 g / 10 min.

(B) The melt tension at 190 to 260 ° C must be 2 gf or more. Fluorine-containing resins that deviate from these requirements can be used as molding materials for chemical liquid containers that require sufficient stress crack resistance and a smooth inner surface, especially for large chemical liquid containers. Can not be used. For example, if the melt flow rate is less than 0.1 g / 10 minutes, the melt fracture at the exit of the extruder die during blow molding. The surface of the molded product becomes rough and rough as a result. If the time exceeds 2 OgZ10 minutes, the sagging of the parison will increase during blow molding, and it will be extremely difficult to adjust the thickness of the molded product. The melt tension (1

If the value of (9 0 2 6 0 ^) is smaller than 2 gf, the strength of the melt during blow molding will be insufficient, the dripping of the parison will be large, and the wall thickness will be uniform. Molded product cannot be obtained. If a material without these characteristics is formed at a very low blow molding temperature of 180 ° C or less, the problem of the sagging of the Paris can be solved. It is. However, the resulting molded article has a rough surface, has poor stress crack resistance, and is insufficient as a chemical solution container.

 The melt flow rate (at 230) of the present invention is 0.:! ~ 20 g ZIO, preferably 0.3-10 g Z10, more preferably 0.3-5 g ZIO It is. Preferred retentions (190 to 260, preferably between 200 and 240) are between 5 and 50 gf, and are more preferred. Or 10 to 50 gf.

 The fluorine-containing resin molding material of the present invention preferably further has MwZMn of 2.0 or more.

 M w ZM n is an index of the molecular weight distribution, and has properties such as moldability at the time of molding a single piece, sagging of a preform, and stress cracking of a molded article. It is a measure of the mechanical properties. When MwZMn is smaller than 2.0, the sagging of the preform tends to increase. Preferred MwMn is between 2.0 and 5.0.

 The fluorine-containing resin used in the present invention has the above-mentioned melting (blowing) molding performance and the concentration of fluorine ion generated in the range of 200 to 260 is not less than 10%. It is less than ppm. When the fluorine-containing resin is melt-molded, it is exposed to the outside in the form of corrosive gas such as hydrofluoric gas due to thermal decomposition or the like. Since this hydrofluoric acid corrodes the metal materials (SUS, SACM-based alloys, SCM-based alloys) of general-purpose plastic molding machines, high-cost corrosion-resistant metal materials are used as described above. I had to use it. This point is also a factor that hinders the general use of fluorine-containing resins.

The fluoropolymer containing low melting point used in the present invention has a melting form temperature (190 to 260, preferably 200 to 240 ° C). Since the amount of fluorine ion generated is 10 ppm or less, preferably 5 ppm or less, the conventional general-purpose plastic molding machine can be used without using a corrosion-resistant metal material. It can be molded using Further, since the metal corrosion resistance is excellent, a container with little metal contamination and a small amount of metal leaching in a molded product at the time of molding can be obtained.

 The fluorine-containing resin molding material of the present invention is particularly suitable as a material for blow molding, but is not limited to blow molding, but may be a roto-molding method or a welding method. In addition to the lining method, it is also useful as a molding material for extrusion molding, injection molding, transfer molding, and inflation film extrusion molding. . The molding temperature is usually 190 to 260, preferably 200 to 2401 :.

 The present invention also relates to a process for molding a fluororesin molding material having the above-mentioned specific melt flow rate and melt tension. Related to blow molded containers.

 According to the present invention, a large-sized container with an internal capacity of 20 liters or more and an extremely smooth inner surface, which cannot be produced with conventional fluororesin molding materials, is used for general purposes. Plastic molding machines are available.

In general, as the blow molding method, an extrusion blow molding method and an ejection blow molding method are known. The protruding method used in the present invention may be any method, but the continuous extrusion method conventionally used in the manufacture of a polyethylene chemical solution container is used. An extrusion or extrusion method using an accumulator head method is preferred. Of these, in order to suppress the deformation of the preform, the extrusion time of the preform is reduced by using an accumulator head, and the time required for extruding the preform is shortened. Weight of preform An accumulator-head method that minimizes the amount is more preferable.

 As described above, strict quality is required for chemical liquid containers, particularly for chemical liquid containers used in semiconductor manufacturing processes. Among these, the smoothness of the inner surface of the shape surface is related to the molding technology, but the present invention has achieved that requirement by modifying the molding material. It is a thing. The smoothness of the inner surface is necessary to reduce contamination (metal impurities, fine particles, etc.) in the container cleaning process before the high-purity chemical is filled. It is an important factor.

 For example, when a fluorine-containing resin having the above-mentioned properties (A) and (B) and having a melting point of 230 ° C. or less is used, particularly in a large container. The surface does not become rough and the thickness of the container does not become uneven. In the present invention, the difference in wall thickness (%) of the container wall may be 60% or less, preferably 40% or less, and more preferably 20% or less. it can .

 According to the present invention, the surface roughness Ra (centerline average roughness) is 0.0 or less, preferably 0.05 m or less, and more preferably 0.05 m or less. A uniform container with a minimum wall thickness of 0.1 mm or less at 2 m or less, preferably 1 to 5 mm, and a wide range of 0.1 to 1000 liters Can be provided. The blow-molded container of the present invention has a capacity of 20 liters or more, preferably 300 liters or more, preferably 50 liters or more, which could not be manufactured conventionally. Can be provided.

Also, in the blow molding method, as the height of the container increases, the difference in wall thickness increases and molding becomes difficult, but according to the present invention, the maximum outer diameter is increased. Relatively tall vessels with a height to height ratio of 1 or more can be provided. The container of the present invention can be used for storing and transporting various chemicals, particularly high-purity chemicals called semiconductor manufacturing grades. Typical chemicals include, for example, sulfuric acid, hydrochloric acid, ammonia water, hydrogen peroxide solution, hydrofluoric acid, ammonium fluoride, zonal fluoride for semiconductor production. Hydrofluoric acid, phosphoric acid, nitric acid, nitric acid, acetic acid, isopropyl alcohol, n-butyl acetate, monophenolic amine, and the like Chemical solutions containing surfactants such as fluorine-based anion surfactants and hydrocarbon-based anion surfactants can be used. In addition, it is also useful as a container for storing and transporting pharmaceutical intermediates and blood.

 The container of the present invention manufactured in this manner can be used as it is as various chemical liquid containers as it is, but is used, for example, as a chemical liquid container for semiconductor manufacturing. In some cases, it is used in a separate outer container, often referred to as a container. The purpose of the container is to reinforce and transport the container inside, and it is known to be made of metal, FRP, Polyethylene, Polypropylene, etc. It is.

 In the container of the present invention, the container wall of the container is multi-layered into two or more layers, and the innermost layer is formed by a blow molding method using the above-mentioned fluorine-containing resin molding material. It can be a prepared container.

 The material of the layers other than the innermost layer may be the same as or different from the material of the innermost layer. Examples of the dissimilar materials include known fluororesins, FRP, and polyethylene which do not have the characteristics of the present invention. In particular, in pro-molding, it is more economical if the upper and lower loss portions of the parison are re-ground and used as the outer layer material.

The multilayer structure has two layers if the innermost layer is the molding material of the present invention. Alternatively, a structure having three or more layers may be used. Further, as the molding material of the present invention constituting the innermost layer, it is preferable to use one obtained by stabilizing the above-mentioned unstable terminal group.

 The shape of the multi-layer container is the same as that of the single-layer container. Regarding the dimensions, since the multi-layer structure improves the strength and durability of the whole container, the size can be further increased and the innermost layer can be made thinner. When multi-layered, the thickness of the container wall is about 0.1 to 10 mm in total, usually:! It is about 5 mm. In particular, the thickness of the innermost TFE-based copolymer layer can be about 0.05 to 2 mm, preferably about 0.1 to 1 mm. The weight can also be reduced.

 Next, the present invention will be described based on an embodiment, but the present invention is not limited to only the embodiment.

 The characteristics adopted in the present invention were measured by the following methods.

 (Melt flow rate)

 Specified in accordance with ASTMD-3330. The measurement temperature was 230 ° C and the load was 5 kgf.

 (Meltition)

 Using a capillary graph manufactured by Toyo Seiki Seisaku-sho, a temperature of 230 mm from a 2 mm inner diameter and a 10 mm long cavity die, shearing speed 7 6 sec — Measure the tension when pulling out the strand extruded at 1 at the speed of lm Z min.

 (Defluoridated ion concentration)

After setting the quartz tube in an electric furnace and raising the temperature to the melting temperature (230), weigh 2 g of the test resin into the quartz tube and insert it. Flow 30 ml of nitrogen from one side of the quartz tube. Bubble for one hour into a bottle containing 20 ml of pure water at the outlet side of the quartz tube. Then, measure the fluorine ion dissolved in pure water by ion chromatography.

 The defluoridated ion concentration was calculated by the following equation. Fluorine ion measurement value X 20

 Defluorinated ion concentration (ppm) =-Test resin amount (g)

(Surface roughness Ra)

 Using a surface roughness measuring device (Surfcom 47 OA) manufactured by Tokyo Seimitsu Co., Ltd., the sample surface is obtained by a diamond pick-up with a stylus tip 2 // mR. 2.5 mm is automatically measured at a pick-up speed of 0.3 mm Z seconds. The surface roughness Ra is the center line average roughness specified in JIS B0601-19802.

 (Thickness difference)

 The maximum thickness (mm) and the minimum thickness (mm) of the container obtained by blow molding excluding the mold matching part were measured with a dial gauge, and calculated by the following equation. Maximum thickness (mm)-minimum thickness (mm)

 Wall thickness difference (%) = X100

Maximum wall thickness (mm) Normally, a blow molding device is used that pushes out a parison from the top of the mold and blows air or the like from the bottom of the mold. In such a case, the lower part of the parison is sandwiched by a mold to form the mouth of the container, and the upper part of the nose is used as the bottom of the container. The part is the thinnest, and the upper part of the body of the container is the thickest. Therefore, the thickness difference is calculated by measuring the thickness of each of these parts. (Chemical resistance crack resistance)

 A S T M D 1 6 9 3 — Follow 70. The test temperature is 60: The number of test samples n is 5, and the number of cracks on the samples 5 days later is visually examined. The sample holder shall be made of Polytetrafluoroethylene, and the test container shall be made of TFE no-perfluoro (alkyl vinyl ether) copolymer (PFA).

 ,: ∑έ Corrosive)

 Place the test metal sample (3 cm square, 1 mm thick) and 100 g of the test resin sample in an aluminum container, and place nitrogen in an oven at the molding temperature. Visually inspect the surface condition of the metal sample after exposure to airflow for 100 hours.

Example 1

After putting 320 liters of deoxygenated water into a glass lining auto crepe of 128 liters in volume and evacuating it, Add 128 kg of perfluorocyclobutane and 256 kg of hexafluoropropylene, and stir the inside of the autoclave (180 rpm). At 35 ° C. Furthermore, after charging CH 2 = CF (CF ₂ ) 3H 6 40 g and 150 g of xan to the mouth of the cylinder, the monolayer in the gas phase inside the autoclave was charged. The monomer composition (mol%) is tetrafluoroethylene (TFE), ethylene (Et) / hexafluoropropylene (HFP) = 39.5-5. The pressure in the autoclave is set to 1 so that TFE and Et are

It was press-fitted until it became 2 kgf / cm ^ G.

Then, 2.56 kg of di-n-propyl paroxyl deer-ponate (50% methanol diluent) was charged and polymerization was started. Since the pressure decreases with the progress of polymerization, additional injection of a monomer gas mixture of TFEZEt / HFP (mol% ratio: 40.3 / 43.9 / 15.8) was performed. While keeping the pressure at 12 kgf Z cm 2 G, continue the polymerization and add CH 2 = CF (CF ₂ ) 3H. The consumption of the monomer mixture is 1. The mixture was continuously charged into a microphone mouth pump at a rate of 2% by weight. After the polymerization was carried out for 38 hours, the residual monomer and the solvent were recovered, and the water was extracted.

 In order to stabilize the copolymer chain end obtained in this way, newly add 320 liters of pure water and 6 liters of 28% ammonia water. And 8 Ot: for 3 hours to make the end of the copolymer chain amido, followed by washing and drying to obtain 189 kg of a powder of a terminal-stabilized copolymer. This copolymer powder was pelletized by using a 50Φ single screw extruder to obtain a molding material of the present invention.

 Various physical properties of the obtained copolymer of the present invention were examined by the methods described above.

 Composition (mol% ratio): T F E Z E t Z H F P Z C H?

-CF (CF ₂ ) 3H = 39.7 / 44.8 /

1 5.0 / 0.5

 Melting point: 1 in 6 2

 Melt flow rate (230 *): 1.4 g / 10 minutes

 Melt tension (230): 18.9 gf Defluoridated ion concentration: 0.8 ppm

 (Blow molding of containers)

Using this molding material, a blow molding machine (one-time operation for an accumulator) can be used to form a 150 mm die and a 14.7 mm mand. Using a container, set the injection time at 30 to 30 seconds and set the container to 20 liters in capacity (maximum outer diameter 300 mm, height

455 mm) was blow-molded.

 No melt fracture occurred at the outlet of the personal computer, and the personal computer was transparent.

 The appearance of the obtained container was good, the surface roughness Ra of the inner surface was 0.02 ^ m, the minimum wall thickness was 2.3 mm, and the wall thickness difference was 19.3%. there were.

Comparative example

 Polymerization was performed in the same manner as in Example 1 except that the amount of hexane at the mouth was changed to 350 g to obtain a copolymer powder, which was then pelletized to produce a molding material for comparison. did . The various physical properties of this product were as follows.

 Composition (mol% ratio): TFEEtHFP / CH2

 C F (C F 2) 3H = 40 2/4 4.6 / 4.7 / 0.5

 Melting: 1 in 6 3

 Melt flow rate (230): 28 g ZLO content Melt tension (230): 1.5 gf

 Defluoridated ion concentration: 1.4 ppm

 Then, when a chemical container having a content of 20 liters was blow-molded in the same manner as in Example 1 using the molding material for comparison, the draw- The downturn was severe and blow moldability was found. In addition, the obtained container had a large difference in wall thickness of 85%, and the wall thickness at the lower part of the container was particularly impractical.

Example 2

Molding material of the present invention obtained in Example ¾.

table 1

_{* 1: C 12 H 25 (} C 6 H 5 SOQH) O (C 6 H 5 S0 3 H)

Example 3

 The molding material of the present invention obtained in Example 1 and the chemical resistance of 110 to £ used in Example 2 were examined in accordance with 13 K 7 11 14. Each molding material was punched into a dumbbell-shaped sample of ASTMD 638 Type 5 (3.5 mm in width, 25.4 mm in length, and 1.0 mm in thickness). It was immersed in the same chemical solution as at room temperature (at 23). After soaking for one month, the sample was taken out, washed thoroughly with water, wiped with dry gauze, weighed immediately, and weighed after soaking. The weight change rate (%) was calculated by the following equation (average of 5 samples). Weight after immersion (g)-Weight before immersion (g)

 Weight change rate (%) = X 100

 To determine the residual strength (%) immediately after immersion weight (g) and after the weight measurement, the strength and elongation at the yield point and at the break point were measured. Was The sample was measured using a tensile tester UCT-500 manufactured by Orientec Co., Ltd. to obtain a distance between chucks of 25.4 mm and a chuck speed of 5 mm. Performed at 0 mm / min (average of 5 pieces). Strong elongation before immersion-Strong elongation after immersion

Strong elongation residual ratio (%) = 100 X 100 strong elongation before immersion Table 2

_{* 1: C 12 H 25 (} C 6 H 5 S0 3 H) O (C 6 H 5 S0 3 H)

Example 4

 The test temperature in Example 3 was set at 60, and the chemicals were hydrofluoric acid (50%), nitric acid (60%), sulfuric acid (98%), and hydrogen peroxide (30%). The rate of change in weight (%) and the rate of residual elongation (%) after immersion were measured.

 Table 3 shows the results.

 Table 3

実施例 5

Example 5

 The metal corrosivity of the molding material of the present invention obtained in Example 1 and PFA (PFAAP—210, melting point 308, manufactured by Daikin Industries, Ltd.) were examined by the above-described method. Table 4 shows the results.

As the test metal materials, the same materials used in general-purpose plastic molding machines were used. SACM 645 + Nitriding: Nitriding of aluminum, chromium, and molybdenum steel materials of type 645.

 SCM 440: Chromium-Mollibden steel material 440

SUS304: 304 hot-rolled stainless steel

 The defluoridation ion concentration of the used PFII (at a melting measurement temperature of 370) was 49.2 ppm.

 Table 4

Example 6

 (Metal dissolved concentration measurement)

The container having an internal volume of 20 liters obtained in Example 1 was sufficiently washed with hydrofluoric acid (50%, manufactured by Daikin Industries, Ltd.), and then the metal concentration of the container was reduced to 0.1 lppb. After filling 15 kg of the following 50% hydrofluoric acid and leaving it to stand at room temperature for 1 power month, 1 liter sampling was performed, and the dielectric coupled plasma mass spectrometry CP-MS) device (manufactured by Seiko Denshi Kogyo KK). The measured metals are Fe, Na, Ni, Cu, Cr, Zn,

Mg, C a, C o, K, L i, M n, and A l were used.The sampling solution was concentrated to dryness on a white metal plate, and T A M A

Tamper made by CHEMICAL was replaced with 0.1 N nitric acid, and the concentration ratio was set to 100 times.

 For comparison, the same method as above was performed using a 20-liter HDPE container (manufactured by Kodama Resin Kogyo Co., Ltd.) used as a high-purity semiconductor chemical solution container. After standing for a month, ICP-MS was used for measurement.

Table 5 shows the metal leaching concentration (ppb, detection limit of 0.1 lppb) after standing for one month.

Table 5

F e Na N i Cu C r Zn Mg C a C 0 K L i Mn A 1

Example 1

 0.01 <0.01 <0.01 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0 . 01 Container for semiconductor

 0.02 <0.01 <0.01g 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.01 <0.01 <0.01 <0.01

HD Ε Ε container

From these results, it can be seen that it can be used as a low-metal-contained container for high-purity semiconductor chemicals. Industrial applicability

 According to the present invention, even a high-purity chemical solution containing a surfactant is stable, and a large blow-molded container made of a fluororesin containing a smooth inner surface can be formed at a relatively low temperature. It can be provided at the molding temperature.

 In addition, since the amount of fluorine ion generated at the molding temperature is small, there is little danger of corrosion, and a general-purpose plastic molding machine can be used. The cost can be reduced.

Claims

Scope of demand 1. The melt flow rate at (A) 230 T: is 0.1 to 20 g ZLO, and (B) 190 to 260 "Ό Has a melt tension of 2 to 5 O gf, and (C) A molding material consisting of a melt-moldable fluorine-containing resin with a melting point of 23 or less with a fluorine-free ion concentration of 10 ppm or less at 190 to 260ー Containers obtained by molding.  2. (A) Melt flow rate at 230 ° C is 0.3 to 10 g / min, and (B) Melt at 190 to 260 ° C 2. The container according to claim 1, wherein the tension is 10 to 50 gf.  3. The container described in claim 1 that is used as a container for a high-purity chemical solution.  4. The surface roughness Ra (center line average roughness) of the inner surface of the container is 0.  The container according to claim 1 or 2, wherein the container is 0 m or less.  5. When the fluororesin content is 30 to 90 mol% of tetrafluoroethylene and at least 70 to 10 mol% of at least one other monomer. The container according to any one of claims 1 to 3, which is a nitrogen copolymer.  6. The container according to any one of claims 1 to 4, wherein the fluorine-containing copolymer is a fluorine-containing copolymer in which an unstable group at a molecular end is stabilized. . 7. Containers manufactured by blow molding using a molding material consisting of a fluorine-containing resin having a melting point of 230 or less and having a content of 20 liters or more. The minimum thickness of the container is 0.1 A blow-molded container having a thickness of at least mm and a surface roughness Ra (central average roughness) of the inner surface of the container of 0.07 / m or less. 8. The container according to claim 6, wherein the ratio of the height to the maximum outer diameter is 1 or more.  9. The container according to any one of claims 1 to 7, wherein a difference in wall thickness of the container wall is 60% or less.  10. The container according to any one of claims 1 to 8 containing a high-purity chemical solution.  11. Use of the container according to any one of claims 1 to 8 for storing and transporting a high-purity chemical solution.  12. It is a melt-formable resin containing 30 to 90 mol% of tetrafluoroethylene units, a melting point of 230, and the following fluorine-containing resin. A) The melt rate at 230 is 0: 0 to 20 g ZLO, and (B) the melt temperature at 190 to 260 is A low-temperature blow molding material having an area of 2 to 50 gf and a (C) defluoridation concentration of 190 to 260 ppm of 10 ppm or less. 13. The blow molding material according to claim 11, wherein the fluorine-containing resin is one in which an unstable group at a molecular terminal is stabilized. Claims of amendment [January 19, 2000 (19.1.00) Accepted by the International Bureau: Claims 3-6, 8—11 and 13 at the time of filing were amended; other claims remained unchanged . (2 pages)] 1. (A) The melt flow rate at 230 is 0.1 to  (G) The melt tension at (B) 190 to 260 is 2 to 50 gf, and the (C) Molding made of a melt-moldable fluororesin with a melting point of 230 "C or less, with a fluorine-free ion concentration of 190 to 26 Ot: less than 10 ppm A container obtained by blow molding a material.  2. The melt flow rate of (A) 230 "C is 0.3 to 10 gm for 10 minutes, and (B) the flow rate of 190 to 260 g The container according to claim 1, wherein the ruttion is 10 to 50 gf.  3. (After amendment) The container according to claim 1 or 2, which is used as a container for a high-purity chemical solution.  4. The container according to any one of claims 1 to 3, wherein the surface roughness Ra (centerline average roughness) of the inner surface of the container is 0.07 / zm or less (after correction).  5. (After correction) The fluororesin content is 30 to 90 mol% of tetrafluoroethylene and at least one other monomer 70 to 10 The container according to any one of claims 1 to 4, wherein the container is a fluorine-containing copolymer with the content of mol%.  6. (After amendment) Claims 1 to 5 wherein the fluorine-containing copolymer is a fluorine-containing copolymer in which the unstable group at the molecular end is stabilized. The container described in any of the above.  7. Containers manufactured by blow molding using a molding material consisting of a fluorine-containing resin with a melting point of 230 or less and having a content of 20 liters or more. Therefore, the minimum thickness of the container is 0.1 正; ¾ (Article 19 of the Convention) A blow-molded container having a diameter of not less than mm and a surface roughness Ra (center line average roughness) of the inner surface of the container of not more than 0.07 / xm. 8. The container according to claim 7, wherein the ratio of the height to the maximum outer diameter is 1 or more (after correction).  9. (After correction) The container according to any one of claims 1 to 8, wherein the difference in wall thickness of the container wall is 60% or less.  10. The container according to any one of claims 1 to 9, wherein the container contains a high-purity chemical solution (after correction).  11. (After amendment) How to use the container described in any of Claims 1 to 9 for storing and transporting high-purity chemicals. 12. It is made of a fluorine-containing resin that is melt-moldable, contains 30 to 90 mol% of tetrafluoroethylene units, and has a melting point of 230 or less. (A) The melt mouth rate at 230 is 0.11 to 20 g / 10 minutes, and (B) the melt rate at 190 to 260 is For low-temperature blow molding with an area of 2 to 50 gf and a defluoridation concentration of (C) 190 to 260 below 10 ppm material. 13. The material for molding according to claim 12, wherein the fluorine-containing resin is one in which unstable groups at the molecular terminals are stabilized. Paper collected (Article ^ Article 19) Statements under Article 19 of the Convention Amend claims as follows: (1) Amend “paragraph 1” in the first line of claim 3 to “paragraph 1 or 2”.  (2) Amend “paragraph 1 or 2” in the second line of claim 4 to “any of paragraphs 1 to 3”.  (3) Amend “Items 1 to 3” in lines 3 and 4 of Claim 5 to “Items 1 to 4”.  (4) Amend “Items 1 to 4” in lines 2 and 3 of Claim 6 to “Items 1 to 5”.  (5) Amend “paragraph 6” in the second line of claim 8 to “paragraph 7”. (6) Amend “Items 1 to 7” in the first and second lines of Claim 9 to “Items 1 to 8”.  (7) Amend “Items 1 to 8” in the first line of claim 10 to “Items 1 to 9 J”.  (8) Amend “Items 1 to 8” in the first and second lines of Claim 11 to “Items 1 to 9”.  (9) Amend “Item 11” in the second line of Claim 13 to “Item 12.” The above amendments are corrections for obvious mistakes. that's all