(19) a
`
`)
`
`E"'°”*‘s°“°spa‘°"‘a"“
`
`European Patent Office
`Office européen des brevets
`
`IIIIIIIIIIIIIHIIIIIIIIIIIIliIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIiii
`
`(11)
`
`EP 0 738 580 A1
`
`(12)
`
`EUROPEAN PATENT APPLICATION
`published in accordance with Art. 158(3) EPC
`
`(43) Date of publication:
`23.10.1996 Bulletin 1996/43
`
`(51) Int. 01.6: 3290 49/22, BZQC 49/04
`
`(21) Application number: 959057533
`
`(22) Date Of filing: 11-01-1995
`
`(84) Designated Contracting States:
`DE ES FR GB IT SE
`
`(30) Priority: 11.01.1994 JP 1379/94
`
`(71) Applicants:
`- NIPPON STEEL CHEMICAL CO., LTD.
`Chuo-ku, Tokyo 104 (JP)
`- NIPPON STEEL CORPORATION
`
`Tokyo 100-71 (JP)
`
`(54)
`
`MULTILAYERED BLOW MOLDING
`
`The technical challenge is to provide a multi-
`(57)
`layer blow-molded article comprising a plurality of types
`of thermoplastic resins wherein the layers are strongly
`secured to each other without separating under normal
`service conditions, and the layers and/or portions
`defined in a circumferential direction, both of which have
`diverse resins, can be easily separated from each other
`in recycling or reuse.
`
`There is provided a multi-layer blow-molded article
`wherein in a multi-layer marginal-wall region foamed of
`a plurality of layers, a convexly crooked portion project-
`ing generally convexly from inside to outside is so
`formed that the molding shrinkage factor of a resin for
`use in a more outer layer is larger than that of a resin for
`use in a more inner layer, and a concavely crooked por-
`tion denting generally concavely from outside to inside
`is so formed that the molding shrinkage factor of a resin
`for use in a more outer layer is smaller than that of a
`resin for use in a more inner layer; and all the layers of
`the molded article are fittingly secured to each other by
`means of a clamping force resulting from the difference
`in molding shrinkage factors of the resins constituting
`the layers and/or portions defined in a circumferential
`direction in the multi-layer marginal-wall region.
`The present invention may find extensive applica-
`tion in the field of large industrial parts such as automo-
`bile bumpers.
`
`(86) International application number:
`PCT/JP95/ooo1 5
`
`(87) International publication number:
`W0 95/1 871 2 (13.07.1995 Gazette 1995/30)
`
`(72) Inventor: OHTA, Akira
`Chiba 299-01 (JP)
`
`(74) Representative: Hansen, Bernd, Dr. Dipl.-Chem.
`et al
`
`Hofimann, Eitle & Partner,
`Patentanwalte,
`Arabellastrasse 4
`
`81925 Mfinchen (DE)
`
`
`
`
`
`Printed by Rank Xerox (UK) Bustness SerVIces
`2.13.8414
`
`Wavelock
`Exhibit1014
`Page1
`(cid:58)(cid:68)(cid:89)(cid:72)(cid:79)(cid:82)(cid:70)(cid:78)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:91)(cid:75)(cid:76)(cid:69)(cid:76)(cid:87)(cid:3)(cid:20)(cid:19)(cid:20)(cid:23)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:20)
`
`EP0738580A1
`
`

`

`EP 0 738 580 A1
`
`Description
`
`Technical Field
`
`The present invention relates to a multi-Iayer blow-molded article having hollow structure made by a blow molding
`technique using a plurality of thermoplastic resins as raw materials.
`
`Background Art
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`Various techniques are known by which multi-layer, hollow-structure molded articles are made of a plurality of ther-
`moplastic resins of raw materials. Needless to say, the primary object of making multi-layer molded articles is generally
`to provide an article having different features of individual materials. For example, this means to provide a molded arti-
`cle which is outstanding in both physical properties A and B by means of laminating a resin (a) that is superior in prop-
`erty A but is inferior in property B, and a resin (b) that is superior in property B but is inferior in property A.
`In order to cope with such requirements, multi-Iayer blow-molding techniques have been developed. For example,
`much attention has been focused on, especially automobile fuel tanks as large industrial parts. Many proposals have
`been made on methods and machines for producing them as in Japanese Patent Publication Nos. 52-37026 (1977) and
`57-53175 (1982). At present, multi-Iayer blow-molded fuel tanks as products come into actual use in some automobiles.
`Other examples of the multi-Iayer blow-molded articles are containers for mayonnaise and ketchup consumed in gen-
`eral homes. In the production of such containers, a parison is formed in such a manner that a plurality of resin layers
`are positioned concentrically and that each layer has a generally equal thickness over its entire circumference.
`Also known are multi-layer blow-molded articles made of parisons each of which has the different number and
`thickness of layers partially. For example, Japanese Patent Laid-open No. 2-88214 (1990) discloses a multi-layer blow-
`molded plastic article made of a multi-layer parison in which a part of the parison is different in the number and thick-
`ness of layers from the other part of the parison. In the example of the patent, a trilayer parison is disclosed in which
`the outer layer is preferably made of a composition comprising crystalline polyolefin and engineering plastic or a ther-
`moplastic, elastomeric, polyolefin composition, the intermediate layer is preferably a reprocessed-material layer com-
`prising, e.g., flash formed in the production of multi-Iayer blow-molded articles and defective moldings or a foamed-
`material layer comprising polyolefin or the reprocessed material mentioned above, and the inner layer is preferably
`made of crystalline polyolefin.
`In addition, Japanese Patent Laid-open No. 4-14427 (1992) discloses a method of producing multi-Iayer blow-
`molded articles using a parison in which approximately half of the parison in the circumferential direction is made of a
`material for reinforced portions and the remaining part is made of a material for external portions or approximately half
`of the parison in the circumferential direction is made of a material for reinforced portions and the remaining part is
`made of a laminate consisting of a material for reinforced portions and a material for external portions. However, in a
`multi-Iayer blow-molded article produced by such a method, the layers are generally adhered to each other by means
`of adhesives or fusing so that the layers will not separate from each other.
`In this respect, Japanese Patent Laid-open No. 2-88214 (1990), for example, discloses a multi-layer blow-molded
`article in which the outer layer is made of a composition comprising crystalline polyolefin and engineering plastic or a
`thermoplastic, elastomeric, polyolefin composition, the inner layer is made of crystalline polyolefin, and the intermediate
`layer is a reprocessed material comprising, e.g., tlash formed in the production of the multi-layer blow-molded article
`itself and defective moldings or a foamed-material layer comprising polyolefin or the reprocessed material mentioned
`above, whereby there is provided affinity between the layers due to the common polyolefin component present in all the
`layers to obtain high interlaminar strength without using adhesives. In addition, Japanese Patent Laid-open No. 4-14427
`(1992) teaches that when layers are not adhered to each other by fusing, the layers are integrated by means of adhe-
`sives, or the resins for use in the layers are modified so that the layers are adhered to each other by fusing. In the inven-
`tions disclosed in both patents, the layers are strongly adhered to each other by means of adhesives or fusing.
`However, from the viewpoint of resource conservation and control of global environmental pollution which may be
`caused due to molded synthetic-resin articles being disposed, the need for recycling or reuse of molded synthetic-resin
`articles is now increasing. Thus, the requirement for recycling or reuse of the resins used for molded multi-layer, hollow-
`structure articles mentioned above is also increasing. However, when the layers each consisting of diverse resins are
`ground and granulated together, the resultant reprocessed resin is far from providing the features of the individual res-
`ins. lt rarely provides even the average feature of the individual resins and generally becomes a low-grade resin losing
`all the features of the resins.
`
`Therefore, in order to recycle or reuse such multi-Iayer, hollow-structure molded articles, the layers each consisting
`of diverse resins are required to be separated from each other. However, once the layers have been adhered to each
`other, it becomes difficult to make them separate. Furthermore, to make them separate mechanically or chemically,
`expensive equipment would be needed. However, to invest in such equipment for recycling or reuse may be commer-
`cially unprofitable and be unfeasible in many cases. In this respect, proposed is a method of making layers consisting
`
`Wavelock
`Exhibit 1014
`Page 2
`(cid:58)(cid:68)(cid:89)(cid:72)(cid:79)(cid:82)(cid:70)(cid:78)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:91)(cid:75)(cid:76)(cid:69)(cid:76)(cid:87)(cid:3)(cid:20)(cid:19)(cid:20)(cid:23)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:21)
`
`

`

`EP 0 738 580 A1
`
`of diverse resins easily separate from each other, whereby resins in each layer of multi-Iayer molded articles are sepa-
`rated into the individual types of resins for recycling.
`For example, Japanese Patent Laid-open No. 5-069452 (1993) discloses an injection-molded automobile bumper
`in which a sheet of resin that is not adhesive to the resin of the main body of the bumper is used. The non-adhesive
`resin sheet is molded into a resin sheet of a desired shape conformed to the front portion of the bumper. This molded
`sheet is attached to the mold of an injection molding machine and a resin is then injected into the back surface of the
`molded sheet to form the main body of the bumper, whereby the molded sheet and the main body of the bumper are
`integrated. In an automotive bumper thus produced, the molded sheet and the main body of the bumper are not sepa-
`rated from each other under normal service conditions but are easily separated if force is exerted thereon.
`However, in this case, just as in the case of a multi-Iayer laminated film, two steps are needed; one for molding a
`resin sheet first and one for attaching the resultant molded sheet to a mold, followed by injection molding the main body
`of a bumper. Furthermore, no proposal is made as to how to separate with exerting force the molded sheet and the main
`body of the bumper, both of which are not separated from each other under normal service conditions.
`Accordingly, although conventional molded multi-layer articles have great value in their intended use, they present
`a difficult problem to be solved in view of recycling and reuse.
`
`Disclosure of the Invention
`
`The present inventors have assiduously studied in order to develop such a multi-Iayer blow-molded article that the
`layers are strongly secured to each other without separating under normal service conditions and without losing the
`advantages of the multi-layer article and that the layers having diverse resins and/or portions defined in a circumferen-
`tial direction can be easily separated from each other in recycling and reuse. As a result, the present inventors have
`found that the above-mentioned problem can be solved in such a way that all the layers of a multi-layer marginal-wall
`region in a hollow molded article are fittingly secured to each other by means of a clamping force resulting from the dif-
`ference in molding shrinkage factors of the resins constituting the layers and/or portions defined in a circumferential
`direction in the multi-layer marginal-wall region. Thus, the present invention was completed.
`Therefore, an object of the present invention is to provide such a multi-layer blow-molded article that the layers are
`strongly secured to each other without separating from each other under normal service conditions and without losing
`the advantages of the multi-Iayer molded article and that the layers and/or portions defined in a circumferential direc-
`tion, both of which have diverse resins, can be easily separated from each other in recycling and reuse.
`Thus, in accordance with a first aspect of the present invention, there is provided a multi-layer hollow blow-molded
`article comprising a plurality of thermoplastic resins each having different molding shrinkage factors; wherein, in a multi-
`layer marginal-wall region of the hollow molded article, convexly crooked portion(s) projecting generally convexly from
`inside to outside are so formed that the molding shrinkage factor of a resin for use in a more outer layer is larger than
`that of a resin for use in a more inner layer, and concavely crooked portion(s) denting generally concavely from outside
`to inside are so formed that the molding shrinkage factor of a resin for use in a more outer layer is smaller than that of
`a resin for use in a more inner layer; and all the layers of the molded article are fittingly secured to each other by means
`of a clamping force resulting from the difference in molding shrinkage factors of the resins constituting the layers and/or
`portions defined in a circumferential direction in the multi-layer marginal-wall region.
`In a preferred aspect of the present invention, a multi-layer blow-molded article preferably comprises, in the mar-
`ginal wall of the hollow molded article, a plurality of portions which are different in at least one of the type of resin, the
`number of layers and the thickness of a layer in the circumferential direction. In addition, it is preferred that basically the
`layers and portions defined in a circumferential direction, both of which have diverse resins, are not adhered to each
`other by means of adhesives or fusing, because those layers and portions, if so made, can be easily separated from
`each other in recycling or reuse. However, those layers and portions defined in a circumferential direction may be tem-
`porarily adhered to each other to such an extent that they can retain their proper positions.
`In another preferred aspect of the present invention, convexly crooked portions and/or concavely crooked portions
`in the aforementioned multi-layer marginal-wall region may include clamping portions by which the layers are fittingly
`secured to each other to a larger extent in such a manner that in the convexly crooked portions, any one of more outer
`layers embraces any one of more inner layers and that in the concavely crooked portions, any one of more inner layers
`embraces any one of more outer layers.
`In still another preferred aspect of the present invention, the outermost layer of the aforementioned hollow molded
`article comprises a plurality of portions having diverse resins and the portions comprise, at the boundaries, joining por-
`tions to be joined together extending outwards from the portions having diverse resins. These joining portions may be
`fixed by a suitable joining means so that the layers of the article can be fittingly secured to a lager extent. Examples of
`the joining means include a joining part such as a bolt/nut or clip and a joining structure such as a fastener or zipper
`fixed to or formed in the joining portions.
`In accordance with a second aspect of the present invention, there is provided a multi-Iayer blow-molded article
`wherein the molded article is a molded multi-Iayer, hollow-structure molded article which comprises in combination a
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`Wavelock
`Exhibit1014
`Page3
`(cid:58)(cid:68)(cid:89)(cid:72)(cid:79)(cid:82)(cid:70)(cid:78)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:91)(cid:75)(cid:76)(cid:69)(cid:76)(cid:87)(cid:3)(cid:20)(cid:19)(cid:20)(cid:23)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:22)
`
`

`

`EP 0 738 580 A1
`
`surface layer having a surface area of at least 50% of the entire surface area of the molded article and a hollow structure
`integrallyjoined to the back surface of the surface layer. The surface layer is made by an injection molding technique or
`vacuum forming technique, and the hollow structure is made by a blow molding technique; the molding shrinkage factor
`of a resin constituting the surface layer is larger than that of a resin constituting the hollow structure; both the left and
`right edges of the surface layer have clamping portions for clamping the hollow structure in such a manner that the sur-
`face layer embraces the hollow structure; and the surface layer is fittingly secured to the hollow structure on the basis
`of the difference between the molding shrinkage factor of the resin constituting the surface layer and that of the resin
`constituting the hollow structure. In an aspect of the invention, the clamping portions of the surface layer and the corre-
`sponding stepped portions of the hollow structure each include a plurality of marginal joining portions extending there-
`from. The marginal joining portions of the clamping portions can be strongly secured to those of the stepped portions
`by using joining means. Furthermore, the surface layer may include a com/ex locking portion projecting inward from the
`inner surface thereof and the hollow structure may include a concave locking portion in a position corresponding to the
`convex locking portion of the surface layer. By locking the convex locking portion to the concave locking portion, the sur-
`face layer can be more strongly secured to the hollow structure. In this aspect of the present invention, one of the sur-
`face layer and the hollow structure may be molded first and then attached to a molding die for use in molding the other
`one. The latter one is then molded on the back surface of the former one, thereby integrating both of them to produce
`a molded article.
`
`In accordance with a third aspect of the present invention, there is provided a multi-layer blow-molded article filled
`with a foamed resin inside the hollow molded article wherein the hollow molded article comprises a plurality of types of
`thermoplastic resins having different molding shrinkage factors in such a manner that the layers are not adhered to
`each other; the molding shrinkage factor to be inherent in a resin for use in a more outer layer is smaller than the mold-
`ing shrinkage factor to be inherent in a resin for use in a more inner layer; and after the foaming resin has been filled,
`the overall dimensional shrinkage factor of the molded article is smaller than the molding shrinkage factors to be inher-
`ent in resins constituting the layers.
`In this aspect of the invention, there may be provided, for example, a molding method comprising: using thermo-
`plastic resins A and B having the molding shrinkage factors a and b respectively to blow mold a multi-layer parison hav-
`ing the resin A in the outer layer and the resin B in the inner layer, wherein a < b and resin A and B are not adhesive to
`each other; and while a molded article still residing in a mold is cooled, filling the internal space of the molded article
`with a foaming resin primarily comprising of a resin of the same type as that of the resin B for use in the inner layer to
`expand the foaming resin, whereby the molded article is cooled to be solid with keeping its expansion pressure toward
`the molded article in the mold. In the application of this method, the dimensional shrinkage factor p of the foamed-filler-
`containing molded article after released from the mold may be kept equal to or less than the molding shrinkage factor
`"a" of the resin A for use in the outer layer (p < a), whereby a multi-Iayer blow-molded article with a high degree of adher-
`ence is obtained, wherein the inner surface of the outer layer of the multi-Iayer molded article is not adhered chemically
`to the outer surface of the inner layer containing the foamed filler.
`Description is made more in detail below.
`It is a phenomenon that the
`Generally, thermoplastic resins have such a property that they shrink after molding.
`dimension of a molded article at the time when a set period of time has been elapsed after released from the mold
`becomes smaller than the corresponding dimension of a mold cavity. Because of this phenomenon, the molding shrink-
`age factor of a resin is herein defined as the ratio of a decrease in the dimension of the resin to the corresponding
`dimension of a mold cavity. The molding shrinkage factor is an inherent property in an individual type of resin. There-
`fore, it is natural that the molding shrinkage factors vary among types of resins. In the case of a multi-layer blow-molded
`article, it is uncertain which of the molding shrinkage factors of resins for use in the layers becomes predominant. Thus,
`the molding shrinkage factor is defined as distinguished from the dimensional shrinkage factor of a molded article itself.
`In the present invention, an inner layer can be strongly clamped by an outer layer with the layers being fittingly in
`contact with each other on the basis of the difference in molding shrinkage factors of the layers. To be more specific, in
`generally convexly crooked portions, the inner layer comprises a resin A having a low molding shrinkage factor "a" and
`the outer layer comprises a resin B having a higher molding shrinkage factor "b" (a < b), whereby the dimensional
`shrinkage factor "q" of a resultant multi-layer blow-molded article is typically between a and b (a < q < b). In this case.
`the resin B for use in the outer layer can shrink more if it is present alone, but actually it shrinks with its shrinkage factor
`being nearly equal to q, because the inner layer having a low shrinkage factor prevents the outer layer from shrinking.
`On the contrary, the resin A for use in the inner layer is applied an external pressure due to the strong shrinkage force
`of the outer layer and, as a result, the resin A is forced to shrink with its shrinkage factor being nearly equal to "q" over
`its inherent molding shrinkage factor "a". Thus, there is provided an intended condition that the inner layer is strongly
`clamped by the outer layer.
`In the first and second aspects of the present invention, a plurality of types of thermoplastic resins having different
`molding shrinkage factors are used to mold a hollow molded article. The difference between the molding shrinkage fac-
`tors of the adjacent layers in the molded article is preferably 0.2% or more and more preferably 0.3% or more. In addi-
`tion, preferably the difference between the molding shrinkage factors of an outer layer and an inner layer having an
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`Wavelock
`Exhibit 1014
`Page 4
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`
`

`

`EP 0 738 580 A1
`
`intermediate layer therebetween is 0.5% or more and preferably 0.8% or more. When the difference between the mold-
`ing shrinkage factors of adjacent layers is 0.2% or more and the difference between an outer layer and an inner layer
`having an intermediate layer therebetween is 0.5% or more, in the multi-layer marginal-wall region of a hollow molded
`article, layers and portions defined in a circumferential direction may be secured to each other to the desired extent
`which varies in applications. Such resins may be easily selected, for example, on the basis of the molding shrinkage
`factors of the resins listed in Table 1.
`
`Table l
`
`Molding shrinkage
`factor
`
`
`
`
`Thermoplastic Resins
`
`
`[l] Polyolefin Resins (HM-HDPE,
`
`HDPE, MDPE, L-LDPE, LDPE, V—LDPE,
`PP)
`
`
`
`
`[2] Elastomeric Polyolefin Resins
`
`(Elastomeric resins based on the
`
`aforementioned group of resins [1])
`
`
`
`[3] PET (Polybutylene terephthalate
`Resins)
`
`
`
`
`0.8% or more
`[4] Filler—Reinforced—Polyolefin
`Resins (Resins of aforementioned
`
`group [1] reinforced with a filler)
`
`
`
`[5] Polyamide Resins (PA6, PA66,
`
`
`PA6-10, PA6-12, PAll, PA12, PA46)
`
`
`0.8% or less
`[6] PS (Polystyrene Resins), ABS
`
`Resins), Modified PPE (Modified—
`VPolyphenylene ether Resins)
`
`
`[7] Filler—Reinforced PBT Resins
`
`
`[8] PSF (Polysulfone Resins), PES
`(Polyether sulfone Resins
`
`
`Resins), AS (Acrylonitrile-Styrene
`
`(Acrylonitrile-Butadiene-Styrene
`
`Wavelock
`Exhibit1014
`Page5
`(cid:58)(cid:68)(cid:89)(cid:72)(cid:79)(cid:82)(cid:70)(cid:78)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:91)(cid:75)(cid:76)(cid:69)(cid:76)(cid:87)(cid:3)(cid:20)(cid:19)(cid:20)(cid:23)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:24)
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`EP 0 738 580 A1
`
`Table 1
`
`(Continued)
`
`Molding shrinkage
`factor
`
`Thermoplastic Resins
`
`0.5% or less
`
`[9] PC (Polycarbonate Resins), PET
`
`
`
`(Polyethylene terephthalate
`
`Resins), PPS (Polyphenylene sulfide
`
`Resins), PEI (Polyether imide
`
`Resins), PI (Polyimide Resins),
`
`PEEK (Polyether ether—ketone
`
`Resins), LCP (Liquid Crystal
`
`Polymer Resins)
`
`[lOJFiller—Reinforced Resins
`derived from the resins below
`
`(PA Resins, PS, ABS, AS, Modified
`
`PPE, PSF, PES, PC, PET, PPs, PEI,
`
`PI, PEEK, LCP)
`
`[ll] Polymer alloy Resins
`
`(Polymer alloy Resins derived from
`
`a plurality of species belonging to
`
`the aforementioned groups [3],
`
`[5],
`
`[6],
`
`[7],
`
`[8],
`
`[9] and [10]).
`
`_ Herein, fillers include glass
`'
`fibers, glass beads, carbon fibers,
`calcium carbonate, talc, mica,
`
`blast—furnace slag, metallic
`
`Fillers
`
`powder, woodmeal and the like.
`
`In the production of the aforementioned multi-Iayer blow-molded articles of the present invention, it is preferred that
`a multi-Iayer parison to be formed has a generally equal thickness over the entire periphery thereof, but the present
`invention is not limited thereby. The occurrence of wrinkles and deformations in the multi-Iayer parison may be thus pre-
`vented when the multi-layer parison is extruded in the production of the multi-layer blow-molded article.
`In the first and second aspects of the present invention, layers having diverse resins in the multi-layer marginal-wall
`region of a hollow molded article and portions defined in a circumferential direction are not adhered butfittingly secured
`to each other by means of a clamping force resulting from the difference in molding shrinkage factors of the resins con-
`stituting the layers in the multi-Iayer marginal-wall region and/or the portions defined in a circumferential direction. Thus,
`thwmaMpmMmdwmdmaWQmmmmmwmwmammmmemeowmommmmmmwmwww
`keep the hollow molded article in a desired shape under normal service conditions. In addition, in recycling and reuse.
`the layers and/or portions defined in a circumferential direction, both of which have diverse resins, can be easily sepa-
`rated from each other, for example, by removing joining means such as bolts/nuts if desired, followed by pressing or
`twisting the hollow molded article to deform.
`In the aforementioned first and second aspects of the present invention, a combination of resins has a limitation.
`To be more specific, there is a limitation that a resin for use in an outer layer should be larger in molding shrinkage factor
`than a resin for use in an inner layer. In the case where a resin for use in an outer layer is smaller in molding shrinkage
`
`Wavelock
`Exhibit 1014
`Page 6
`(cid:58)(cid:68)(cid:89)(cid:72)(cid:79)(cid:82)(cid:70)(cid:78)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:91)(cid:75)(cid:76)(cid:69)(cid:76)(cid:87)(cid:3)(cid:20)(cid:19)(cid:20)(cid:23)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:25)
`
`10
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`15
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`20
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`25
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`30
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`35
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`40
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`45
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`50
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`55
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`

`

`EP 0 738 580 A1
`
`factor than a resin for use in an inner layer, the inner layer separates from the outer layer in an initial stage so that a
`multi-layer molded article thus produced does not serve the purpose of the present invention. On the contrary, in the
`third aspect of the present invention, there is provided a multi-layer blow-molded article in which the inner layer is
`strongly clamped by the outer layer to retain a high degree of adherence between the layers even in the case where a
`resin for use in an outer layer is smaller in molding shrinkage factor than a resin for use in an inner layer.
`In the third aspect of the present invention, while a molded article shaped by a mold is still in the mold and is cooled,
`a foaming resin is filled into the internal space of the molded article to expand, then the molded article is cooled to be
`solid in the mold while being applied an internal pressure due to the expansion of the foamed resin, whereby the dimen-
`sional shrinkage factor "p" of the foamed-filler-containing molded article can be smaller than the inherent dimensional
`shrinkage factor "q" of a molded article without an expanded filler. By controlling the expanding process, the value "p"
`can be reduced to approximately one third of the value "".q Even if the molded article is a multi-Iayered one in which the
`molding shrinkage factor of a resin for use in the inner layer is larger than that of a resin for use in the outer layer, the
`dimensional shrinkage factor of the entire inner layer including a foamed material can be smaller than the molding
`shrinkage factor of the outer layer on the basis of a pressure due to the expansion of the foamed material.
`In Table 2, listed are resins for use in an inner layer and foaming resins based on the same types of resins as the
`resins for use in an inner layer, which may be used according to the third aspect of the present invention.
`In Table 3,
`also listed are resins for use in an outer layer which may be used in combination with the resins for use in an inner layer
`listed in Table 2. In Table 4, listed are combinations which should be excluded from them because they are chemically
`adhered to each other.
`
`Molding
`shrinkage factor
`
`1.3% or more
`
`Table 2
`
`Resins for Use in Inner Layer
`
`Foaming Resins
`
`[1] PE (Polyethylene) Resins HM-HDPE, HDPE, MDPE,
`LDPE, L-LDPE, V-LDPE
`
`Foaming PE Resins
`
`[2] Elastomeric Polyethylene Resins Elastomeric Resins
`based on the resins of the group [1] mentioned above
`
`0.8% or more
`
`[3] Filler- Reinforced PE Resins Resins of above--men-
`tioned group [I] reinforced a filler
`
`1.3% or more
`
`0.8% or less
`
`Foaming PP Resins
`
`Foaming PS Resins
`
`--—-
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`10
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`15
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`20
`
`25
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`30
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`35
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`40
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`45
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`50
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`55
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`Wavelock
`Exhibit1014
`Page?
`(cid:58)(cid:68)(cid:89)(cid:72)(cid:79)(cid:82)(cid:70)(cid:78)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:91)(cid:75)(cid:76)(cid:69)(cid:76)(cid:87)(cid:3)(cid:20)(cid:19)(cid:20)(cid:23)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:26)
`
`

`

`EP 0 738 580 A1
`
`Table 3
`
`Resins for Use in Outer Layer
`
`Molding
`shrinkage factor
`
`[11] PBT (Polybutylene terephthalate Resins)
`
`[12] Polyamide Resins PA6, PA66, PA6-10, PAS-12, PA11, PA12, PA46
`
`0.8% or less
`
`[13] PS (Polystyrene Resins), ABS (Acrylonitrile-Butadiene-Styrene Resins), AS
`(Acrylonitrile-Styrene Resins), Modified PPE (Modified-Polyphenylene ether Resins)
`
`[14] Filler-Reinforced PBT Resins
`
`[15] PSF (Polysulfone Resins), PES (Polyether sulfone Resins)
`
`0.5% or less
`
`[16] PC (Polycarbonate Resins), PET (Polyethylene terephthalate Resins), PPS
`(Polyphenylene sulfide Resins), PEI (Polyether imide Resins) , Pl (Polyimide Resins),
`PEEK (Polyether ether ketone Resins), LCP(Liquid Crystal Polymer Resins)
`
`[17] Filler-Reinforced Resins below PA Resins, PS, ABS, AS, Modified PPE, PSF,
`PES, PC, PET, PPS, PEl, Pl, PEEK, LCP
`
`[18] Polymer alloy Resins (Polymer alloy Resins derived from a plurality of species
`
`belonging to the aforementioned groups [11], [12], [13], [14], [15], [16] and [17]).
`Resins
`
`Table 4
`
`Resins for Use in Inner
`
`Resins for Use in Outer
`
`Layer
`
`layer
`
`PS Resins and Filler—
`Reinforced PS Resins
`
`Modified PPE Resins and
`Filler~Reinforced Modified
`PPE Resins
`
`ABS Resins and Filler—
`
`PC and Filler—Reinforced PC
`
`Reinforced ABS Resins
`
`The term 'filler' used in Tables 2, 3, and 4 has the same meaning as that used in Table 1. When a multi-layer blow-
`molded article in the third aspect of the present invention is a trilayered one, any resin which does not adhere chemically
`to a resin to be used in the outer layer of the molded article may be selected from the resins listed in Table 3 as a resin
`for use in the intermediate layer. Preferably, a foaming resin and a resin constituting an inner layer are of the same type.
`When a foaming resin and a resin for use in an inner layer are of the same type, they may easily separate from a resin
`for use in an outer layer after use, which is preferred from the viewpoint of recycling.
`In a multi-layer blow-molded. foamed-filler-containing article produced in such a way as described above. the inner-
`most layer containing the foaming material is cla