Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/14—Layered products comprising a layer of synthetic resin next to a particulate layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B1/00—Layered products having a non-planar shape
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
  • B32B27/286—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42 comprising polysulphones; polysulfides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
  • B60K15/03—Fuel tanks
  • B60K15/03177—Fuel tanks made of non-metallic material, e.g. plastics, or of a combination of non-metallic and metallic material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/726—Permeability to liquids, absorption
  • B32B2307/7265—Non-permeable
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2323/00—Polyalkenes
  • B32B2323/04—Polyethylene
  • B32B2323/043—HDPE, i.e. high density polyethylene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2605/00—Vehicles
  • B32B2605/08—Cars
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
  • B60K15/03—Fuel tanks
  • B60K2015/03032—Manufacturing of fuel tanks
  • B60K2015/03046—Manufacturing of fuel tanks made from more than one layer

Definitions

• polyamides are superior in gasoline barrier properties but poor in impact resistance .
• polyolefins are inferior in gasoline barrier prop ⁇ erties but superior in impact resistance . For this reason, many attempts have been made to produce a con ⁇ tainer superior in both impact resistance and gasoline barrier properties from a polyamide and polyolefin in combination .
• Japanese Patent Publication No . 14695/1985 discloses a molded article of composite mate ⁇ rial composed of polyolefin, polyamide, and alkylcarboxyl- substituted polyolefin, with the polyolefin forming a con- tinuous matrix phase, the polyamide existing in layer form in the continuous matrix phase, and the alkylcarboxyl- substituted polyolefin existing between the polyamide layers .
• a container formed from this composite material is poor in low-temperature impact resistance despite the modified polyolefin incorporated therein and the polyamide dispersed therein in layer form, because the polyamide layer is poor in adhesion to the continuous matrix phase of polyolefin .
• Another disadvantage is that the composite material of multilayer structure makes it difficult to recycle flash .
• the above-mentioned impermeable container has a disadvantage that the sulfonation for surface treat ⁇ ment costs much time and expenses . Moreover, it has been found that the sulfonation itself is not satisfactory.
• the present inventors carried out a series of researches whic led to the finding that the good gasoline barrier proper- ties and impact resistance are obtained by multilayer blow molding from sulfonated high-density polyethylene in combination with untreated high-density polyethylene instead of sulfonating the molded container, the former component being prepared by sulfonating high-density poly ⁇ ethylene in the form of powder having a large surface area.
• the sulfonated multilayer container pertaining to the present invention comprises an interlayer formed from sulfonated high-density polyethylene powder and inner and outer layers of high-density polyethylene.
• the sulfonated multilayer container may have, if necessary, an additional layer of modified high-density polyethylene between the interlayer and each of the inner and outer layers, said first layer having good adhesion to the other layers .
• the method for producing the sulfonated multi ⁇ layer container according to the present invention com ⁇ prises the steps of sulfonating high-density polyethylene powder having a particle diameter of 100-3000 ⁇ with a gas containing 12-25 vol% of S0 3 at 45-60 * C, and subjectin the sulfonated high-density polyethylene together with untreated high-density polyethylene to multilayer blow molding process, so that the sulfonated high-density poly- ethylene forms the interlayer and the untreated high- density polyethylene forms the inner and outer layers .
• the present invention will be described in more detail .
• the interlayer in the sulfonated multilayer container of the present invention is made of high-density polyeth- ylene having a density higher than 0.93 g/cm 3 , preferably 0.94-0.97 g/cm 3 , a weight-average molecular weight higher than 100, 000, preferably higher than 150, 000, a melt index (ML: 190 * C, 2.16 kg load) lower than 1.0 g/10 min, prefer ⁇ ably 0.2-0.01 g/10 min (which translates into a high-load melt index (HLMI : 190 * C. 21.6 kg load) lower than 70 g/10 min, preferably 20-1 g/10 min) .
• HLMI high-load melt index
• the high- density polyethylene have a weight average molecular weight higher than 100, 000, preferably higher than 150, 000 (say 200, 000) .
• the MI of small values may be replaced by the HLMI (high-load melt index) in order to avoid errors in measurements.
• HLMI high-load melt index
• the preferred HLMI ranges from 20 to 1 g/10 min .
• the high-density polyethylene is not limited tb homopoly ers . It may also include copolymers of ethylene with an ⁇ -olefin such as propylene, butene-1 , and hexene-1.
• the high-density polyethylene is sulfonated in the form of powder . Having a large surface area, powder is capable of rapid and effi ⁇ cient sulfonation .
• the high-density polyethylene powder should have a particle diameter smaller than 5, 000 ⁇ , preferably from 100 to 3, 000 ⁇ m . With a particle diameter larger than 5, 000 ⁇ , the high-density polyethylene powder undergoes sulfonation so inefficiently, that it is a non ⁇ sense to use powder . Reducing the particle diameter belo 100 ⁇ m produces no effect commensurate with it .
• the sulfonation of high-density polyethylene powder is accomplished by exposing the powder to an S0 3 -containin gas .
• the treating gas usually contains S0 3 in an amount o 12-25 vol%, with the remainder being an inert gas such as nitrogen .
• the S0 3 -containing gas should be passed through the high-density polyethylen powder held in a breathable container such as a wire net .
• An alternative method for sulfonation consists of fluidiz- ing the high-density polyethylene powder with the S0 3 - containing gas in a fluidized bed. In either cases, the sulfonation should be performed at 40-70 * C, preferably 45-60 * C, for 3-10 minutes.
• the S0 3 - containing gas should be purged with nitrogen gas, and residual S0 3 should be removed by absorption into sulfuric acid in a vent scrubber.
• a sulfonated high- density polyethylene powder having a degree of sulfonation of 1-5 wt%.
• the sulfonated high-density polyethylene powder does not provide satisfactory gasoline barrier properties. Reducing the degree of sulfonation below 5 wt% produces not effect commensurate with it.
• Ammonia is preferable because of its ability to be used for gas phase reaction.
• the neutralization is accomplished with a neutral iz ⁇ ing agent in an amount of 2 mol for 1 mol of sulfonic groups. Therefore, the volume of ammonia. gas should be twice that of S0 3 gas that has bonded to the high-density polyethylene . Neutralization with ammonia gas should be performed at 45-60'C for 4-9 minutes . After the neutral ⁇ ization is complete, the residual ammonia gas should be purged with nitrogen gas .
• the high-density polyeth- ylene for the inner and outer layers may be the same as that used for the interlayer . It should preferably be a high-molecular weight high-density polyethylene having a weight-average molecular weight higher than 150 , 000 from the standpoint of impact resistance.
• the multilayer container is composed of three layers, that is, an interlayer 1 of sulfonated high- density polyethylene and an inner layer 2 and an outer layer 2' of untreated high-density polyethylene, as shown in Fig. 1.
• the interlayer 1 should have a thickness of 10-500 ⁇ jn.
• the inter ⁇ layer 1 does not provide the multilayer container with satisfactory gasoline barrier properties . With a thickness in excess of 500 ⁇ m, the interlayer 1 does not produce any effect commensurate with the increased thickness.
• the preferred thickness of the interlayer 1 is 100-200 ⁇ m .
• the inner layer 2 and the outer layer 2' both should have a thickness of 1.5-5 mm . With a thick ⁇ ness less than 1.5 mm, they do not provide the multilayer container with sufficient mechanical strength and impact resistance . With a thickness in excess of 5 mm, they do not produce any effect commensurate with the increased thickness .
• the multilayer container is composed of an interlayer 1 of sulfonated high-density polyethylene, an inner layer 2 and an outer layer 2' of untreated high- density polyethylene, and additional layers 3 and 3' of modified high-density polyethylene each interposed between the interlayer 1 and the inner layer 2 and between the interlayer 1 and the outer layer 2' , as shown in Fig . 2.
• the modified high-density polyethylene is one which is obtained by modifying the same high-density polyethyl ⁇ ene as mentioned above with an unsaturated carboxylic acid or anhydride thereof .
• Examples of the unsaturated carbox ⁇ ylic acid or anhydride thereof include monocarboxylic aci (such as acrylic acid and methacrylic acid) , dicarboxylic acid (such as maleic acid, fumaric acid, and itaconic acid) , and dicarboxylic acid anhydride (such as maleic anhydride and itaconic anhydride) .
• monocarboxylic aci such as acrylic acid and methacrylic acid
• dicarboxylic acid such as maleic acid, fumaric acid, and itaconic acid
• dicarboxylic acid anhydride such as maleic anhydride and itaconic anhydride
• T are dicarboxyl ic acids and anhydrides thereof .
• the modified high-density polyethylene should contain the unsaturated carboxylic acid or anhydride thereof in an amount of 0.2-0 . 6 mol% . With an amount less than 0 .2 mol% , it does not permit the modified high-density poly ⁇ ethylene to firmly bond to the high-density polyethylene . With an amount in excess of 0 . 6 mol% , it does not produce any effect commensurate with the increased amount .
• the additional layers 3 and 3' of the modified high-density polyethylene each inter ⁇ posed between the interlayer 1 and each of the inner and outer layers 2 and 2' , should have a thickness of 10-500 ⁇ m.
• the additional layers 3 and 3' of the modified high-density polyethylene do not exhibit good adhesion to the interlayer 1 and the inner and outer layers 2 and 2' , and . hence contribute little to the improvement in impact resistance.
• the interlayer 1 and the inner and outer layers 2 and 2' may have the same thicknesses as mentioned above.
• the multilayer container may be produced by multilayer blow molding process, which is carried out as follows :
• the sulfonated high-density polyethylene for the inter ⁇ layer and the untreated high-density polyethylene for the inner and outer layers are melted and mixed separately at 180-220 * C.
• the melts are fed simultaneously to the multi- layer blow molding die and then extruded from it into a parison.
• the parison is blown up in a mold by hot com ⁇ pressed air to be made into a molded article of desired shape and size.
• the melt of the modified high-density polyethylene should be fed to the multilayer blow molding die simulta ⁇ neously with other melts. Examples
• High-density polyethylene "B-5742" (a product of Tonen Sekiyukagaku K.K. , having an HLMI of 4 g/io min and a density of 0.945 g/cm 3 ) in the form of powder (having a particle diameter of 150-2900 ⁇ m) was sulfonated in the following manner.
• the remaining gas was purged with nitro gen gas and the residual S0 3 was absorbed into H 2 S0 4 by means of a vent scrubber .
• the high-density polyethylene powder was subsequently exposed to an ammonia gas stream at 53 * C for 6 minutes for the neutralization of sulfonic groups .
• the remaining ammonia gas was purged with nitrogen gas .
• a sulfonated high-density polyethylene powder having an HLMI of 5 g/10 min and a density of 0 . 950 g/cm 3 .
• the degree of sulfonation was measured by fluores ⁇ cence X-ray analysis .
• a working curve was prepared for a sulfonated high-density polyethylene plate, and a table showing the relationship between the degree of sulfonation and the number of counts was pre ⁇ pared from the working curve, so that measurements were made by comparing the number of counts of sulfonated high- density polyethylene powder with that of reference in the table .
• the results of the analysis showed that the degree of sulfonation was about 2 wt% .
• the sulfonated high-density polyethylene has a structure as shown below.
• a 40-liter multilayer container of the following structure was produced by multilayer blow molding process from the sulfonated high-density polyethylene powder (for the interlayer) , maleic anhydride-modified high-density polyethylene containing 0.4% of maleic anhydride (made by
• Tonen Sekiyukagaku K.K. for the adhesion layers
• untreated high-density polyethylene B-5742
• Blow molding was accomplished by using a large-sized multilayer blow molding machine with an accumulator head (made by The Japan Steel Works, Ltd.) .
• Inner layer HDPE (B-5742), 1.5-5 mm thick
• Adhesion layer maleic anhydride-modified high-density polyethylene, 150 ⁇ m thick
• Adhesion layer maleic anhydride-modified high-density polyethylene, 150 ⁇ m thick
• Example 2 A 40-liter multilayer container of the following three-layer structure was produced from the sulfonated high-density polyethylene prepared in. Example 1 and untreated high-density polyethylene (B-5742) .
• Inner layer HDPE (B-5742), 1.5-5 mm thick •
• Interlayer sulfonated HDPE (B-5742), 100 ⁇ m thick
• Example 2 The same procedure as in Example 1 was repeated for sulfonation, except that B-5742 (powder of high-density polyethylene for sulfonation) was replaced by a powder (200-2800 ⁇ in particle diameter) of B-6012 having an MI of 0.15 g/10 min and a density of .0 .952 g/cm 3 (a product of Tonen Sekiyukagaku K.K. ) . There was obtained a powder of sulfonated HDPE having an MI of 0.15 g/10 min and a density of 0.957 g/cm 3 .
• a 40-liter multilayer container of the following three-layer structure was produced by multilayer blow molding process from the sulfonated high-density polyeth ⁇ ylene (for the interlayer) and untreated high-density polyethylene (B-5742) .
• Inner layer HDPE (B-5742) , 1 .5-5 mm thick
• Interlayer sulfonated HDPE (B-6012) , 100 ⁇ m thick • Outer layer : HDPE (B-5742) , 1.5-5 mm thick
• Example 2 A 40-liter container of single-layer structure having the same shape and size as that in Example 1 was produced by blow molding process from B-574 high-density polyethylene . This single-layer container was tested in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 2
• a 40-liter five-layer container of the following structure having the same shape and size as that in Example 1 was produced by multilayer blow molding process . from high-density polyethylene (B-5742), nylon 6 (CM-1046, made by Toray Industries, Inc.), and maleic anhydride- modified high-density polyethylene containing 0.4% of maleic anhydride (made by Tonen Sekiyukagaku K.K.). • inner layer: HDPE (B-5742), 1.5-5 mm thick
• Adhesion layer maleic anhydride-modified high-density polyethylene, 200 ⁇ m thick
• Adhesion layer maleic anhydride-modified high-density polyethylene, 200 ⁇ thick
• the present invention provides a sulfonated multilayer container which is composed of an interlayer of highly sulfonated high-density polyethylene and inner and outer layers of high-density polyethylene . Because of this structure, the multilayer container exhib- its good gasoline barrier properties as well as high impact resistance . The interlayer of sulfonated high- density polyethylene is not affected by gasoline because it is isolated from gasoline by the inner layer . There ⁇ fore, the multilayer container of the present invention is suitable for use as the automotive fuel tank and other containers which need gasoline barrier properties. 4. Brief Description of the Drawings:
• Fig 1 is a partial sectional view showing the struc ⁇ ture of the multilayer container in one embodiment of the present invention.
• Fig. 2 is a partial sectional view showing the struc ⁇ ture of the multilayer container in another embodiment of the present invention.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Laminated Bodies (AREA)
• Containers Having Bodies Formed In One Piece (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

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Publications (1)

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ID=18175279

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Cited By (3)

Citations (1)

• 1989
  • 1989-12-15 JP JP1325300A patent/JPH03184845A/ja active Pending
• 1990
  • 1990-12-13 WO PCT/US1990/007505 patent/WO1991009732A1/en active Application Filing
  • 1990-12-13 CA CA002071813A patent/CA2071813A1/en not_active Abandoned

Patent Citations (1)

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