Source: http://www.google.com/patents/US6841041?dq=7,007,239
Timestamp: 2016-09-25 22:30:49
Document Index: 683156729

Matched Legal Cases: ['art 100', 'art 110', 'art 100', 'art 110', 'art 8', 'art 8', 'art 9', 'art 9']

Patent US6841041 - Method for producing pulp molded article - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA method for producing a pulp molded article (7) comprising the steps of supplying a pulp slurry into the cavity (1) of a mold (10) composed of a set of splits (3 and 4), the set of splits (3 and 4) being assembled together to form the cavity (1) with a prescribed configuration, to form a pulp deposited...http://www.google.com/patents/US6841041?utm_source=gb-gplus-sharePatent US6841041 - Method for producing pulp molded articleAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS6841041 B2Publication typeGrantApplication numberUS 10/335,153Publication dateJan 11, 2005Filing dateJan 2, 2003Priority dateFeb 23, 1998Fee statusPaidAlso published asCN1167850C, CN1180163C, CN1265056C, CN1291250A, CN1318668A, CN1532336A, DE69938864D1, EP1081285A1, EP1081285A4, EP1081285B1, US6521085, US6547931, US6830658, US20010040016, US20030121635, US20030145968, WO1999042661A1Publication number10335153, 335153, US 6841041 B2, US 6841041B2, US-B2-6841041, US6841041 B2, US6841041B2InventorsYoshiaki Kumamoto, Kenichi Otani, Shinji Otakura, Tokuo Tsuura, Masataka Ishikawa, Toshiyuki Suga, Akira NonomuraOriginal AssigneeKao CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (32), Non-Patent Citations (27), Referenced by (5), Classifications (37), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetMethod for producing pulp molded article
US 6841041 B2Abstract
A method for producing a pulp molded article (7) comprising the steps of supplying a pulp slurry into the cavity (1) of a mold (10) composed of a set of splits (3 and 4), the set of splits (3 and 4) being assembled together to form the cavity (1) with a prescribed configuration, to form a pulp deposited body (5), feeding a fluid into the cavity (1) to press the pulp deposited body (5) onto the inner wall of the cavity (1) for dewatering.
1. A method for producing a pulp molded article comprising the steps of supplying a pulp slurry into the cavity of a mold composed of a set of splits, the set of splits being assembled together to form said cavity with a prescribed configuration, to form a pulp deposited body, feeding a fluid into said cavity to press said pulp deposited body onto the inner wall of said cavity thereby to dewater said pulp deposited body, wherein a pressing member is inserted into said cavity after formation of said pulp deposited body, said fluid is fed into said pressing member to press said pulp deposited body onto the inner wall of said cavity via said pressing member, and said splits are heated while said pressing member is inserted in said splits, thereby drying said pulp deposited body.
2. The method for producing a pulp molded article as set forth in claim 1, wherein:
said mold is designed to have a slurry inlet gate connecting said cavity and the outside when a pair of said splits are assembled together, said mold is immersed in a pulp slurry with said slurry inlet gate down, and said pulp slurry is sucked up through said slurry inlet gate to deposit pulp fiber on the inner wall of said cavity to form said pulp deposited body. 3. The method for producing a pulp molded article as set forth in claim 1, wherein said pulp deposited body has an opening, the upper edge of said opening is pressed down with a prescribed means to make said edge and its vicinity thicker, said pressing member is inserted into said pulp deposited body before or after or simultaneously with said pressing down, and said fluid is fed into said pressing member to press said pulp deposited body.
4. The method for producing a pulp molded article as set forth in claim 1, wherein said pulp slurry is injected under pressure into said cavity while measuring the amount of flow of said pulp slurry and draining said cavity, and after completion of injection of a predetermined amount of said pulp slurry, pressurized air is introduced into said cavity.
6. The method for producing a pulp molded article as set forth in claim 1, wherein said split has a plurality of hollow chambers which are connected to the inner surface of said split and are connected to a suction means in such a manner that the suction pressure of each hollow chamber can be controlled independently.
7. The method for producing a pulp molded article as set forth in claim 1, wherein:
a first pulp slurry is injected under pressure into said cavity, said cavity is dewatered to form a first pulp layer on the inner wall of said cavity while injecting under pressure a second pulp slurry different from said first pulp slurry in composition into said cavity, and said cavity is dewatered to form a mixed layer on said first pulp layer and a second pulp layer on said mixed layer, the composition of said mixed layer continuously changing from that of the first pulp layer to that of the second pulp layer. 8. The method for producing a pulp molded article as set forth in claim 1, wherein said pulp slurry contains pulp fibers having an average fiber length of 0.8 to 2.0 mm, a Canadian Standard Freeness of 100 to 600 cc, and such a frequency distribution of fiber length as comprises 20 to 90%, based on the total fiber, of fibers whose length ranges from 0.4 mm to 1.4 mm and 5 to 50%, based on the total fiber, of fibers whose length is longer than 1.4 mm and not longer than 3.0 mm.
said pulp molded article has an outermost layer and an innermost layer, the pulp slurry used to form said innermost layer contains pulp fibers having an average fiber length of 0.8 to 2.0 mm, a Canadian Standard Freeness of 100 to 600 cc, and such a frequency distribution of fiber length as comprises 20 to 90%, based on the total fiber, of fibers whose length ranges from 0.4 mm to 1.4 mm and 5 to 50%, based on the total fiber, of fibers whose length is longer than 1.4 mm and not longer than 3.0 mm, and the pulp slurry used to form said outermost layer contains pulp fibers having an average fiber length of 0.2 to 1.0 mm, a Canadian Standard Freeness of 50 to 600 cc, and such a frequency distribution of fiber length as comprises 50 to 95%, based on the total fiber, of fibers whose length ranges from 0.4 mm to 1.4 mm. 10. A pulp molded article obtainable by a process comprising:
supplying a pulp slurry into a cavity of a mold comprising a set of splits, the set of splits being assembled together to form said cavity, to form a pulp deposited body, feeding a fluid into said cavity to press said pulp deposited body onto an inner wall of said cavity, thereby dewatering said pulp deposited body, wherein said pulp slurry contains pulp fibers including wood pulp fibers which are softwood pulp fibers or hardwood pulp fibers and non-wood pulp fibers having a length-weighted average fiber length of 0.8 to 2.0 mm, a Canadian Standard Freeness of 100 to 600 cc, and a frequency distribution of fiber length as follows: 20 to 90%, based on the total fiber content have lengths from 0.4 mm to 1.4 mm, and 5 to 50%, based on the total fiber content have lengths longer than 1.4 mm and not longer than 3.0 mm. 11. A pulp molded article obtainable by a process comprising:
supplying a pulp slurry into a cavity of a mold comprising a set of splits, the set of splits being assembled together to form said cavity, to form a pulp deposited body, feeding a fluid into said cavity to press said pulp deposited body onto an inner wall of said cavity, thereby dewatering said pulp deposited body, said pulp molded article having an outermost layer and an innermost layer, wherein the pulp slurry used to form said innermost layer contains pulp fibers having a length-weighted average fiber length of 0.8 to 2.0 mm, a Canadian Standard Freeness of 100 to 600 cc, and a frequency distribution of fiber length as follows: 20 to 90%, based on the total fiber content of the innermost layer, have fiber lengths from 0.4 mm to 1.4 mm, and 5 to 50%, based on the total fiber content of the innermost layer, have lengths longer than 1.4 mm and not longer than 3.0 mm, and wherein the pulp slurry used to form said outermost layer contains pulp fibers having a length-weighted average fiber length of 0.2 to 1.0 mm, a Canadian Standard Freeness of 50 to 600 cc, and such a frequency distribution of fiber length as comprises 50 to 95%, based on the total fiber content of the outermost layer, of fibers whose length ranges from 0.4 mm to 1.4 mm. 12. The pulp molded article as claimed in claim 11, wherein said pulp slurry is a pulp slurry containing pulp fibers including non-wood pulp fibers, softwood pulp fibers, and hardwood pulp fibers, and
further comprising a mixed layer which is located between said outermost layer and said innermost layer, wherein said mixed layer has a composition that changes from that of said outermost layer to that of said innermost layer. 13. A method for producing a pulp molded article, comprising:
supplying a first pulp slurry into a cavity of a mold comprising a set of splits assembled to form the cavity, thereby forming a pulp deposited body; inserting a pressing member into the cavity; feeding a fluid into the pressing member to inflate the pressing member, thereby pressing the pulp deposited body against the mold to dewater the pulp deposited body; and heating the pulp deposited body to dry the pulp deposited body before removing the pressing member. 14. The method according to claim 13, wherein the supplying includes:
opening a slurry inlet gate of the mold; and providing the first pulp slurry through the slurry inlet gate. 15. The method according to claim 13, further comprising:
pressing an upper edge of an opening of the pulp deposited body, thereby thickening the upper edge. 16. The method according to claim 13, wherein at least one of the first pulp slurry and the second pulp slurry includes pulp fibers having an average fiber length of approximately 0.8 to approximately 2.0 mm, a Canadian Standard Freeness of approximately 100 cc to approximately 600 cc, approximately 20% to approximately 90% of fibers having a length between approximately 0.4 mm to approximately 1.4 mm, and approximately 5% to approximately 50% of fibers having a length between approximately 1.4 mm and approximately 3.0 mm.
17. The method according to claim 16, wherein at least one of the first pulp slurry and the second pulp slurry includes pulp fibers having an average fiber length of approximately 0.2 to approximately 1.0 mm, a Canadian Standard Freeness of approximately 50 cc to approximately 600 cc, and approximately 50% to approximately 95% of fibers having a length between approximately 0.4 mm to approximately 1.4 mm.
18. A method for producing a pulp molded article comprising the steps of supplying a pulp slurry into the cavity of a mold composed of a set of splits, the set of splits being assembled together to form said cavity with a prescribed configuration, to form a pulp deposited body, feeding a fluid into said cavity to press said pulp deposited body onto the inner wall of said cavity thereby to dewater said pulp deposited body,
wherein said split has a plurality of hollow chambers which are connected to the inner surface of said split and are connected to a suction means in such a manner that the suction pressure of each hollow chamber can be controlled independently. 19. A method for producing a pulp molded article comprising the steps of supplying a pulp slurry into the cavity of a mold composed of a set of splits, the set of splits being assembled together to form said cavity with a prescribed configuration, to form a pulp deposited body, feeding a fluid into said cavity to press said pulp deposited body onto the inner wall of said cavity thereby to dewater said pulp deposited body,
wherein said pulp slurry contains pulp fibers having an average fiber length of 0.8 to 2.0 mm, a Canadian Standard Freeness of 100 to 600 cc, and such a frequency distribution of fiber length as comprises 20 to 90%, based on the total fiber, of fibers whose length ranges from 0.4 mm to 1.4 mm and 5 to 50%, based on the total fiber, of fibers whose length is longer than 1.4 mm and not longer than 3.0 mm. 20. A method for producing a pulp molded article comprising the steps of supplying a pulp slurry into the cavity of a mold composed of a set of splits, the set of splits being assembled together to form said cavity with a prescribed configuration, to form a pulp deposited body, feeding a fluid into said cavity to press said pulp deposited body onto the inner wall of said cavity thereby to dewater said pulp deposited body,
wherein said pulp molded article has an outermost layer and an innermost layer, the pulp slurry used to form said innermost layer contains pulp fibers having an average fiber length of 0.8 to 2.0 mm, a Canadian Standard Freeness of 100 to 600 cc, and such a frequency distribution of fiber length as comprises 20 to 90%, based on the total fiber, of fibers whose length ranges from 0.4 mm to 1.4 mm and 5 to 50%, based on the total fiber, of fibers whose length is longer than 1.4 mm and not longer than 3.0 mm, and the pulp slurry used to form said outermost layer contains pulp fibers having an average fiber length of 0.2 to 1.0 mm, a Canadian Standard Freeness of 50 to 600 cc, and such a frequency distribution of fiber length as comprises 50 to 95%, based on the total fiber, of fibers whose length ranges from 0.4 mm to 1.4 mm.
This application is a Continuation of application Ser. No. 09/885,982, now U.S. Pat. No. 6,521,085, filed on Jun. 22, 2001 which is a Divisional of application Ser. No. 09/622,043, now U.S. Pat. No. 6,547,931, filed Oct. 10, 2000 which is a National Stage of PCT/JP99/00775 filed Feb. 22, 1999.
The present invention relates to a method for producing pulp molded articles that can be used as, for example, packaging members such as containers and cushioning materials.
Plastics are used as general materials of packaging containers, for example, those with a lid and bottles, for their excellent molding properties and productivity. However, because plastic containers involve various problems associated with waste disposal, pulp molded containers formed by pulp molding have been attracting attention as substitutes for plastic containers. Pulp molded containers are not only easy to dispose of but economically excellent because they can be manufactured by using recycled paper.
The present invention has achieved the above object by providing a method for producing a pulp molded article comprising the steps of supplying a pulp slurry into the cavity of a mold composed of a set of splits, the set of splits being assembled together to form the cavity with a prescribed configuration, to form a pulp deposited body, feeding a fluid into the cavity to press the pulp deposited body onto the inner wall of the cavity thereby to dewater the deposited body.
FIG. 1(a), FIG. 1(b), FIG. 1(c), FIG. 1(d) and FIG. 1(e) schematically show a first embodiment of the present invention, wherein FIG. 1(a) is the step of papermaking, FIG. 1(b) is the step of inserting a pressing member, FIG. 1(c) is the step of pressing, dewatering, and drying, FIG. 1(d) is the step of opening the mold, and FIG. 1(e) is the step of removing a pulp molded article.
FIG. 7(a), FIG. 7(b), FIG. 7(c), FIG. 7(d) and FIG. 7 (e) schematically show a third embodiment of the present invention, wherein FIG. 7(a) is the step of inserting an air feed pipe into a mold and immersing the mold, FIG. 7(b) is the step of sucking up a pulp slurry to form a paper layer, FIG. 7(c) is the step of feeding air into the cavity and dewatering the pulp deposited body, FIG. 7(d) is the step of pulling up the mold and drawing out the air feed pipe, and FIG. 7(e) is the step of opening the mold to take out the pulp deposited body.
Specific embodiments in the practice of the present invention are described below in detail by referring to drawings. To begin with, a first embodiment is described with reference to FIG. 1.
Then, the elastic and stretchable pressing member 6 is inserted into the cavity 1 while evacuating the cavity 1 as shown in FIG. 1(b). The pressing member 6 is used as inflated in the cavity like a balloon thereby to press the pulp deposited body 5 onto the inner wall of the split mold while dewatering thereby to transfer the inner configuration of the split mold to the pulp deposited body. It is therefore preferably made of urethane, fluorine or silicone rubber, elastomers, etc., which are excellent in tensile strength, impact resilience and stretchability. The pressing member 6 may be a hollow bag having no elasticity, in which case, too, the pressing member is inserted into the split mold 3 and 4 to press the pulp deposited body 5 onto the inner wall of the split mold whereby the inner configuration of the split mold can be transferred to the pulp deposited body S. The pressing member 6 of bag form is made of, for example, a synthetic resin film such as a polyethylene film or a polypropylene film, a synthetic resin film having aluminum or silica deposited, a synthetic resin film laminated with aluminum foil, paper, fabrics, and the like. The bag should be equal to or greater in size than the inner contour of the pulp deposited body 5. It is possible that the pressing member is not taken out after pressing the pulp deposited body 5 and left there as a liner of the pulp deposited body.
It is possible to control the wall thickness of the pulp molded article more precisely by providing time lags among the hollow chambers in starting or stopping suction. For example, a pressure gauge (vacuum gauge) is set at each vacuum port, and the hollow chambers 116, 117, and 118 are independently operated under the respective pressures. When the degree of vacuum decreases to a certain set level as pulp fiber is accumulated on the cavity 101, the suction of each of the hollow chambers 116, 117, and 118 is ceased As a result, waste of suction energy can be avoided.
In cases where the corners of the molded article 7 in the vertical cross section and/or the horizontal cross section satisfy the relationship that their density (ρ2) is smaller than the density (ρ1) of the other portions (i.e., ρ1>ρ2) as well as the above-described relationship between T1 and T2, there is produced an effect that two conflicting phenomena—an improvement in compressive strength of the molded article 7 and a reduction in amount of the material used—can result. This effect is more notable when 0.1�ρ1<ρ2<ρ1. The molded article 7 which satisfies these relationships has a compressive strength of 190 N or greater. The compressive strength as referred to here is the maximum strength in compressing the molded article 7 along the direction of height at a speed of 20 mm/min. The above-described relationship between T1 and T2 and between ρ1 and ρ2 can be established by, for instance, properly selecting the pressure or the amount of flow of the pressurizing fluid used in pressing with the pressing member 6, the material or shape of the pressing member 6, the shape of the molded article, and the like in carrying out the aforementioned method.
The split mold shown in FIG. 5 has a papermaking part 100, a manifold part 110, and a mold 120 for creating slurry stagnation (hereinafter “a stagnation-causing mold”). The stagnation-causing mold 120 is inserted into the cavity, which is formed by closing the split molds, to form a space with the inner wall of the cavity in which space the slurry stagnates. The papermaking part 100 and the manifold part 110 have the same structures as shown in FIG. 3.
On butting the splits shown in FIG. 5 to each other, there is formed inside a cavity in conformity to the contour of an article to be molded. The part of the cavity that corresponds to the opening portion of the molded article (this part is referred to as “the part of the cavity corresponding to the opening portion” in this embodiment) has an opening open to the outside. Into this part is inserted a wall 122 for making the slurry stagnant (hereinafter “a slurry stagnation wall”, described later) of the stagnation-causing mold 120. While not depicted, the inner side of the part of the cavity corresponding to the opening portion has grooves corresponding to the screw thread.
It is preferred for the pulp fibers to have an average length of 0.8 to 2.0 mm, particularly 0.9 to 1.8 mm, especially 1.0 to 1.5 mm. If the average fiber length is less than 0.8 mm, cracks tend to develop on the surface of the molded article during papermaking or drying, or the molded article tends to have poor mechanical properties such as impact strength. If the average fiber length exceeds 2.0 mm, the pulp deposited body formed by papermaking tends to have unevenness of thickness only to provide a molded article with poor surface smoothness. The term “average fiber length” as used herein is a value obtained by measuring a frequency distribution of pulp fiber length and calculating an arithmetic mean from the distribution.
The above-described pulp slurry can consist of the above-described pulp fiber and water. The pulp slurry can further contain other components, such as inorganic substances, e.g., talc and kaolinite; inorganic fiber, e.g., glass fiber and carbon fiber, synthetic resin powder or fiber, e.g., polyolefin; nonwood or plant fibers; polysaccharides; and the like.
The amount of these components is preferably 1 to 70% by weight, particularly 5 to 50% by weight, based on the total amount of the pulp fibers and these components.
The average maximum opening width of the first mesh is preferably 1 to 50 mm, particularly 5 to 10 mm. The term “opening width” of the first mesh means the distance between lines of the mesh. If the average maximum opening width is less than 1 mm, the evacuation efficiency is so poor that the pulp fibers are hardly deposited on the surface of the net layer, and a pulp deposited body is hardly formed. If it exceeds 50 mm, the second mesh may pass through between lines of the first mesh to come into contact with the surface of the paper mold. In this case, the evacuation efficiency is reduced in places, resulting in uneven thickness of the pulp deposited body.
On the other hand, the average maximum opening width of the second mesh is preferably 0.05 to 1.0 mm, particularly 0.2 to 0.5 mm. The term “opening width” of the second mesh means the inner size between lines of the mesh. If the average maximum opening width is less than 0.05 mm, the evacuation efficiency is so poor that a pulp deposited body is hardly formed. If it exceeds 1.0 mm, the pulp fibers tend to pass therethrough, and it is difficult to form a pulp deposited body.
The method of producing a pulp molded article having a neck and a closed end (bottom) by use of the above-described mold 10 will be described by referring to FIG. 7. As shown in FIG. 7(a), a pair of splits 3 and 4 are butted to each other to make the mold 10 having a cavity 1 with a net layer 11 fitted on the inner side thereof. An air feed pipe 13 having a collar 12 is inserted into the cavity 1 through the slurry inlet gate 9, and the mold 10 having the air feed pipe 13 inserted therein is immersed in a pulp slurry 14 with its slurry inlet gate 9 down. The air feed pipe 13 has a disc-shaped collar 12 near its end 15 to which an air feed hose 16 is connected. The collar 12 is larger than the section area of slurry inlet gate 9 of the mold 10. The air feed hose 16 is connected to an air feed source (not shown). The air feed pipe 13 is inserted into the cavity 1, led by its free end 17. The length of the air feed pipe 13 from the free end 17 to the collar 12 is such that the free end 17 does not reach the part of the cavity 1 corresponding to the bottom (part 8) when the collar 12 is brought into contact with the slurry inlet gate 9.
On forming a pulp deposited body 5 to a prescribed thickness, the slurry inlet gate 9 is blocked by the collar 12 of the air feed pipe 13 as shown in FIG. 7(c) to stop the flow of the pulp slurry 14. With the slurry inlet gate 9 blocked by the collar 12, air is forced to be fed to the upper space of the cavity 1 (i.e., the vicinity of the cavity part 8′ corresponding to the bottom) through the air feed pipe 13 by means of an air feed source (not shown) while evacuating the cavity 1, whereby the pulp slurry 14 existing in the cavity 1 is discharged outside, and the pulp deposited body 5 is dewatered. Since the evacuation is carried out while feeding air to the upper space of the cavity 1 filled with the pulp slurry 14, the deposited pulp fibers are effectively prevented from being disturbed by the evacuation to provide a molded article with uniform thickness. Since the cross section area of the slurry inlet gate 9 is smaller than that of the cavity part 9 corresponding to the neck, the pulp fibers accumulated on the cavity part 9 corresponding to the neck are effectively prevented from being disturbed by the flow of the pulp slurry 14 thereby to further secure the uniformity in thickness of the neck of the resulting molded article. From the standpoint of shape retention of the pulp deposited body 5 and productivity, it is preferred to conduct the above-described dewatering to such a degree as to reduce the water content of the pulp deposited body 5 to 10 to 95% by weight, particularly 40 to 80% by weight.
In the sixth embodiment, the pulp deposited body 5 formed in the first embodiment is dewatered under pressure by using the pressing member 6 as described above, and the mold 10 is opened to take out the pressure dewatered pulp deposited body 5, which is then set in a heating mold composed of a set of splits 21 and 22 shown in FIG. 9(a). The heating mold has previously been heated to a prescribed temperature. After setting, an edge finishing member 23 comprising a metal-made cylinder, etc. is brought down from above the opening 5 a of the pulp deposited body 5. The edge finishing member 23 has a smooth and flat lower end. A part of a pressing member 24 of the same material and the same shape as the pressing member 6 used in the pressure dewatering is fixed to the inner wall of the edge, finishing member 23 near the lower end. In this state the upper edge of the opening 5 a of the pulp deposited body 5 is pressed down by the edge finishing member 23, and, at the same time, the pressing member 24 is inserted inside the pulp deposited body 5. As shown in FIG. 9(b), it follows that the vicinity of the upper edge is protruded to have an increased thickness, and the shape of the lower end of the edge finishing member 23 is transferred to the upper edge of the opening 5 a of the pulp deposited body 5 thereby to make it smooth and flat. A pressurizing fluid is then fed into the pressing member 24 to press the pulp deposited body 5 onto the inner wall of the split mold 21 and 22 via the pressing member 24 as shown in FIG. 9(c), whereby the pulp deposited body 5 is shaped in conformity to a desired shape and heat dried. After heat drying, the edge finishing member 23 is pulled up, and the pressing member 24 is also taken out of the pulp deposited body 5. The heating mold is opened to take out the pulp molded article. According to this embodiment, the shape of the opening edge of the pulp molded article can be controlled by appropriately selecting the shape of the lower end of the edge finishing member. As a result, the pulp molded article can have improved sealing properties with a cap, etc. and also improved strength at the opening thereof In this embodiment, the pressing member 24 does not always need to be fixed to the edge finishing member 23, in which case the pressing member 24 is inserted either before or after the edge finishing member 23 is pressed down. The material and the shape of the pressing member 24 may be the same as or different from those of the pressing member 6 used for pressure dewatering.
After the pulp deposited body is formed in the cavity 1, the in-cavity pipe 38 is drawn out A pressing member similar to the pressing member 6 used in the first embodiment is inserted into the cavity 1 to dewater the pulp deposited body under pressure. Subsequently, the mold 10 is heated to heat dry the pulp deposited body. Alternatively, the mold 10 is opened to take out the pulp deposited body, which is heat dried in a separately prepared heating mold to obtain a pulp molded article.
In the eighth embodiment, an insert member 50 is inserted into the cavity 1 through the slurry inlet gate 9 of the mold 10 as shown in FIG. 11(a). The cavity configuration of the mold used in this embodiment is conformed to the contour of a carton. The insert member 50 has a supporting member 51 and a hollow or bag-like covering member 52 with which the supporting member 51 is covered. Both the supporting member 51 and the covering member 52 are fixed to a clamp plate 53 with a prescribed means. The supporting member 51 is cylindrical and has a large number of holes 54 on its side. The supporting member 51 has its end 51 a projected outside through the clamp plate 53 and connected to a pressurizing fluid feed source (not shown). There is thus formed a passageway in the insert member 50 from the end 51 a of the supporting member 51, through the inside of the supporting member 51 and the holes 54 on the side wall of the supporting member 51 to the inside of the covering member 52. The covering member 52 is made of a hollow, stretchable elastic member or a nonstretchable bag. Where the covering member 52 is made of an elastic member, the elastic member exhibits elasticity irrespective of whether or not it has a supporting member 51 therein, so that it is easy to keep the elastic member off the inner wall of the cavity 1 in the preliminary expansion hereinafter described. Where, on the other hand, the covering member 52 is made of a nonstretchable bag, the inside of the supporting member 51 is evacuated to bring the bag close to the supporting member 51 so as keep the bag off the inner wall of the cavity 1 while the pulp deposited body is formed. In this particular embodiment, an elastic member is used as the covering member 52. The elastic member can be made of urethane, fluorine rubber, silicone rubber, elastomers, etc., which are excellent in tensile strength, impact resilience, stretchability, and the like. The nonstretchable bag can be of polyethylene, polypropylene, etc.
With the insert member 50 inserted in the cavity 1 and with the slurry inlet gate 9 blocked by the clamp plate 53, a prescribed pressurizing fluid is supplied from a pressurized fluid source into the inside of the covering member 52 through the above-described passageway as shown in FIG. 11(b), thereby to preliminarily expand the covering member 52 to a prescribed size. The covering member 52 thus expanded preliminarily has an almost flat plate shape. The term “expand” as used herein means that the covering member 52 stretches to increase its volume (for example, in the case where the covering member 52 is made of a stretchable elastic member) and that the covering member 52 is not stretchable per se but capable of increasing its volume (for example, in the case where the covering member 52 is made of a nonstretchable bag which is in close contact with the supporting member 51 in an evacuated state). The term “inflate” as used herein has the same meanings.
While the second pulp slurry is injected under pressure, dewatering from the cavity 1 is continued to form a mixed pulp layer (not shown) comprising the components of the mixed slurry on the first pulp layer 5 a Since the proportion of the second to the first pulp slurries in the mixed slurry increases continuously with time, the composition of the mixed layer formed on the first pulp layer 5 a continuously changes from first pulp slurry-rich to second pulp slurry-rich compositions.
According to the present embodiment, it is possible to produce a pulp molded article having more layers than the layer structure shown in FIG. 14. For example, as shown in FIG. 15, a third pulp layer 5 d different in composition from both of the second pulp layer 5 b and the first pulp layer 5 a is formed on the side of the second pulp layer 5 b shown in FIG. 14, and a mixed layer Se whose composition continuously changes from the composition of the second pulp layer 5 b to that of the third pulp layer 5 d is formed between the second pulp layer 5 b and the third pulp layer 5 d, making five layers in all. In this case, a multilayered molded article made up of a plurality of materials is obtained. In another case, another first pulp layer 5 a′ is formed on the side of the second pulp layer 5 b shown in FIG. 14, and a mixed layer 5 c′ whose composition continuously changes from the composition of the second pulp layer 5 b to that of the first pulp layer 5 a′ is formed between the second pulp layer 5 b and the first pulp layer 5 a′, making five layers in all in which the innermost layer and the outermost layer have the same composition. In this case, making the first pulp layers 5 a and 5 a′ of pulp having high whiteness and making the second pulp layer 5 b of pulp having such whiteness as of used paper provide a molded article which has an appearance of high whiteness and yet is competitive in price.
The present invention will now be illustrated in greater detail, but it should be understood that the scope of the present invention is not construed as being limited thereto.
Bottles were molded by the method shown in FIG. 1. The particulars of the pulp in the slurry used are shown in Table 1 below. Molding properties in the molding are also shown in the Table. In Table 1, the LBKP used in Examples 1 to 4 is used paper used in OA equipment, which contains a large amount of virgin pulp and has a small freeness, while the LBKP used in Example 5 is CENIBRA (trade name), which contains a large amount of recycled pulp with a small amount of virgin pulp and has a large freeness.
NBKP/LBKP*1 =
70/30*2 3
LBKP*3 =
50/50*2 4
30/70*2 5
LBKP*4 =
50/50*2 *1Average fiber length of NBKP: 2.29 mm; average fiber length of LBKP: 0.82 mm *2Weight ratio *3Average fiber length of used paper: 1.5 mm; average fiber length of LBKP: 0.82 mm *4Average fiber length of used paper: 1.5 mm; average fiber length of LBKP: 0.81 mm As is apparently seen from the results in Table 1, the molded articles of Examples 1 to 5 prepared from a slurry containing pulp having a specific average fiber length, a specific freeness, and a specific fiber length frequency distribution show satisfactory molding properties. While not shown in the Table, the molded articles of Examples 2, 3 and 5 made of a blend of long pulp fibers and short pulp fibers had particularly excellent surface smoothness.
A slurry for outermost layer containing 1.0% by weight of pulp fiber the physical properties of which are shown in Table 2 was injected into the cavity of the mold shown in FIG. 13 through the slurry inlet gate under a pressure of 0.3 MPa. The cavity was dewatered to form an outermost layer of the slurry for outermost layer on the inner wall of the cavity. Concurrently with the formation of the outermost layer, a slurry for innermost layer containing 1.0% of pulp fiber whose physical properties are shown in Table 2 was injected into the cavity under a pressure of 0.3 MPa. Air is introduced into the cavity through the slurry inlet gate under a pressure of 0.1 MPa to form, on the outermost layer, a mixed layer of which the composition continuously changed from that of the slurry for outermost layer to that of the slurry for innermost layer and, on the mixed layer, an innermost layer was further formed of the slurry for innermost layer. A pressing member comprising an elastic member was inserted into the thus obtained pulp deposited body, and air was fed into the pressing member under a pressure of 1.5 MPa to press the pulp deposited body onto the inner wall of the cavity for dewatering.
The mold was opened to take out the pulp deposited body, which was then set in a heating mold having the same cavity configuration as the shaping mold A pressing member comprising an elastic member is inserted into the pulp deposited body set in the heating mold. Air was introduced into the pressing member under a pressure of 1.5 MPa to press the pulp deposited body onto the inner wall of the cavity while heating the heating mold at 200� C. to dry the pulp deposited body. After the pulp deposited body dried sufficiently, the heating mold was opened to remove the molded bottle. The molding properties of the resulting molded article are shown in Table 2. The surface roughness of the molded article was measured with Surfcom 120A available from Tokyo Seimitsu K.K. The transfer properties of the inner cavity configuration to the molded article were evaluated with the naked eye. A 70 mm long by 20 mm wide piece was cut out of the resulting molded article. The cut piece was partly separated along the mixed layer to prepare a Y-shaped specimen. The specimen was set on a tensile tester with a chuck distance of 20 mm and peeled at a peel angle of 180� and a pulling speed of 30 mm/min. The results of the peel test are shown on Table 2. All these results obtained are shown in Table 2.
A bottle was molded in the same manner as in Example 6, except that the slurry for outermost layer was injected into the cavity to complete formation of the outermost layer, and then the slurry for innermost layer was injected into the cavity to form an innermost layer on the outermost layer. The resulting molded article had no mixed layer between the outermost layer and the innermost layer. The same measurements as described above were made on the resulting molded article. The results obtained are shown in Table 2.
Pulp Fiber of Slurry for
Legnth Frequency
(%): Range A
perties*
The present invention provides a method of producing a pulp molded article which enables designing a complicated shape and integrally molding an opening portion, a body portion, and a bottom portion with no joint seams. The production method of the present invention is applicable to not only hollow containers to put things in but other objects such as ornaments.
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No. 10/365,453, Kumamoto et al., filed Feb. 13, 2003.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7503999Nov 11, 2003Mar 17, 2009Kao CorporationMember for producing castingsUS7815774 *Mar 10, 2003Oct 19, 2010Kao CorporationElements made by paper-making technique for the production of molded articles and production method thereofUS20040069429 *Mar 10, 2003Apr 15, 2004Tokuo TsuuraPart prepared through sheet-making process for use in producing castings and method for preparation tyhereofUS20090211717 *Nov 29, 2006Aug 27, 2009Kao CorporationPart for Producing Castings and Process of Making the SameUS20150308050 *Nov 30, 2012Oct 29, 2015EcologicProcess and machinery for integration of discrete parts into composite containers* Cited by examinerClassifications U.S. Classification162/220, 162/227, 162/149, 162/231, 264/87, 162/219, 162/130, 162/226International ClassificationD21J7/00, D21J3/10, B65D1/02, B65D23/08, B65D43/16, B65D25/32, B65D77/24, B65D1/10Cooperative ClassificationB65D1/10, B65D23/0821, B65D43/162, B65D77/245, B65D25/32, D21J7/00, B65D1/0207, B65D1/0215, D21J3/10, B65D1/0223, Y10T428/1303European ClassificationD21J7/00, B65D77/24B, B65D23/08B1A, B65D43/16B, B65D1/02B1, B65D25/32, D21J3/10, B65D1/02B, B65D1/10, B65D1/02DLegal EventsDateCodeEventDescriptionJun 27, 2008FPAYFee paymentYear of fee payment: 4Jun 13, 2012FPAYFee paymentYear of fee payment: 8Jun 30, 2016FPAYFee paymentYear of fee payment: 12RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services