EP0077131A2 - Manufacture of packaging containers - Google Patents
Manufacture of packaging containers Download PDFInfo
- Publication number
- EP0077131A2 EP0077131A2 EP82304832A EP82304832A EP0077131A2 EP 0077131 A2 EP0077131 A2 EP 0077131A2 EP 82304832 A EP82304832 A EP 82304832A EP 82304832 A EP82304832 A EP 82304832A EP 0077131 A2 EP0077131 A2 EP 0077131A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- reinforcing agent
- liner
- corrugated cardboard
- core liner
- reinforced
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F1/00—Mechanical deformation without removing material, e.g. in combination with laminating
- B31F1/20—Corrugating; Corrugating combined with laminating to other layers
- B31F1/24—Making webs in which the channel of each corrugation is transverse to the web feed
- B31F1/26—Making webs in which the channel of each corrugation is transverse to the web feed by interengaging toothed cylinders cylinder constructions
- B31F1/28—Making webs in which the channel of each corrugation is transverse to the web feed by interengaging toothed cylinders cylinder constructions combined with uniting the corrugated webs to flat webs ; Making double-faced corrugated cardboard
- B31F1/2886—Additionally reinforcing, e.g. by applying resin or wire
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B2100/00—Rigid or semi-rigid containers made by folding single-piece sheets, blanks or webs
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B2110/00—Shape of rigid or semi-rigid containers
- B31B2110/30—Shape of rigid or semi-rigid containers having a polygonal cross section
- B31B2110/35—Shape of rigid or semi-rigid containers having a polygonal cross section rectangular, e.g. square
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B2120/00—Construction of rigid or semi-rigid containers
- B31B2120/70—Construction of rigid or semi-rigid containers having corrugated or pleated walls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
- B31B50/25—Surface scoring
Definitions
- This invention relates to a process of manufactur- in reinforced corrugated cardboard for use in making packaging containers such as carton boxes, and more particularly relates to a process of manufacturing packaging containers made of reinforced corrugated cardboard and having improved pressure resisting properties.
- Corrugated cardboard packaging containers are widely used for various packaging applications because they are light in weight and strong in mechanical strength.
- the commodities to be contained therein are heavy and the corrugated cardboard packaging containers containing the commodities are piled one upon another, there is the danger that the pressure applied to the containers will be beyond the limit of the pressure resisting strength of the corrugated cardboard itself, whereby deformation or breakage of the packaging containers will take place.
- Japanese Utility Model Laid-Open Application 52-84427 it has been proposed that the pressure resisting strength of a packaging container be improved by applying a reinforcing agent to the core of the corrugated cardboard forming the four side portions of the body of the packaging container.
- reinforced corrugated cardboard packaging containers if reinforced corrugated cardboard manufactured by conventional manufacturing process is used, the necessary reinforcement cannot be fully attained.
- a reinforcing agent is applied to a sheet of cardboard, the reinforced cardboard is then formed by pressing into a corrugated core liner, thereafter front and back liners are adhered to both faces of the liner to obtain reinforced corrugated cardboard, thereafter the reinforced corrugated cardboard is scored so that score lines are formed in the cardboard, and a packaging container is then formed.
- the present invention provides a process of manufacturing of a reinforced corrugated cardboard type packaging container in which the score line portions are reinforced without fail and its resistance to pressure is improved to overcome the shortcomings in the prior art.
- a corrugated core liner is adhered at one face to one side liner with an aqueous solution comprising or mainly composed of corn starch, and then the other face of the corrugated core liner is applied with an aqueous solution comprising or mainly composed of corn starch and thereafter is further applied with a reinforcing agent and thereafter the same is adhered to another side liner, and then the two side liners and the corrugated core liner are heated to form reinforced corrugated cardboard, and before completion of hardening of the reinforcing agent score lines for a packaging container are formed in the reinforced region of the reinforced corrugated cardboard.
- a sheet A for a core liner is heated and dried by a preheater 1 and is press-formed into a corrugated core liner by corrugator 2.
- an adhesive agent comprising an aqueous solution mainly composed of corn starch, by a coating apparatus 3, this agent being applied to the crests of one face of the corrugated core liner A.
- the corrugated core liner A is adhered to one side liner B, which is previously heated and dried by a preheater 8.
- aqueous solution mainly composed of corn starch by a coating apparatus 4, this solution being applied to the crests of the other face of the corrugated liner A.
- a reinforcing agent D is applied by an applicator 5, partially in the region in which score lines for forming a packaging container are to be formed later.
- corrugated core liner A is then adhered to another side liner C, so that a sheet of reinforced corrugated cardboard E is formed, this corrugated cardboard being heated by a heating plate apparatus 6 to increase the stickness of the bonding agent.
- the reinforced corrugated cardboard E is continuously fed to a slitter-scorer apparatus 7 and is formed with score lines F, before completion of the hardening of the reinforcing agent D applied to the reinforced corrugated cardboard E as above, and also is cut to any desired width and form.
- the score lines are formed in the reinforced region of the reinforced corrugated cardboard without crushing and destroying the structure of that region.
- the reinforcing agent D is applied to the core liner only in the region thereof in which score lines are to be formed.
- the reinforcing agent D may be applied not only to the foregoing region thereof but also to additional regions thereof corresponding to the whole of the four side walls of the packaging container to be formed.
- the adhesive agent used in this invnetion is an aqueous solution mainly composed of corn starch. It may be gelatinized, and is usually applied to the corrugated core liner A in a viscous condition at a temperature of 70°C to 90°C.
- the adhesive agent may be used in the form of an aqueous solution of corn starch at the time of application thereof to the corrugated core liner, and thereafter may be gelatinized by heating the core liner and both the side liners, such as by use of the heating plate apparatus 6.
- the step of applying the reinforcing agent to the core liner is an additoinal step as compared to the steps of a conventional process of manufacturing corrugated cardboard.
- the aqueous solution mainly composed of corn starch is applied to the core liner and thereafter is heated to gelatinize it
- a reinforcing agent which has been preheated above the gelatinization temperature of the aqueous solution.
- adhesive agents there may be used a Stein-Hall formulation, which is of such a kind that an aqueous solution mainly composed of corn starch is heated to approximately 50°C to 60°C to gelatinize it.
- the reinforcing agent should be preheated to about 60°C or higher, preferably to 70°C to 85°C, taking into consideration its heat loss by radiation at the time of application of the reinforcing agent to the core liner.
- the invention is illustrated by the following Tests.
- the supply speed of the core liner to the heating plate apparatus can be increased and also the water content in the reinforced corrugated cardboard manufactured can be decreased so that the time for complete bonding of the core liner to the side liner can be reduced, resulting in an improvement in the manufacturing efficiency.
- the reinforcing agent should not harden at the temperature of the heated plate of the apparatus 6. If, after the reinforcing agent is applied to the core liner A, it is difficult for the adhesive agent to attach to the core liner A, so that the strength of the bond between the core liner A and the surface liner C is reduced. Therefore, it is preferable to apply the reinforcing agent D after the application of the adhesive agent to the core liner A. Accordingly, it is preferable to use a reinforcing agent able to sufficiently penetrate into the core liner A to which the adhesive agent has already been applied. Furthermore, for the purpose of partially reinforcing only the score line portions at the time of forming a packaging container, it is preferable to use a reinforcing agent which is suitable for application by spraying.
- a reinforcing agent comprising chemically treated or processed starch, water, a surface active agent, and a water resisting agent for starch is especially suitable as the reinforcing agent used in this invention.
- a reinforcing agent comprises 60 wt % to 40 wt % of the processed starch, 40 wt % to 60 wt % of water, 0.1 wt % or less of the surface active agent, and a water resisting agent for starch in an amount which is 6 wt % or more relative to the solid content of the processed starch.
- the reinforcing agent have as high concentration as possible and as low a water content as possible so as not to deform the corrugations of the core liner when the reinforcing agent is applied to the core liner, and that it have so low a coefficient of viscosity as to facilitate application thereof by spraying.
- This coefficient is preferably 100 cps or less (BH type viscosimeter at 20 rpm) at the temperature (20°C to 80°C) for a corrugated cardboard manufacturing process.
- an aqueous solution comprising 40 wt% to 60 wt% of processed starch and 60 wt % to 40 wt % of water.
- the processed starch dextrin, oxidized starch or the like may be used, but in view of the strength of the coating film formed on the core liner by application of the reinforcing agent, and of facilitation of the application by spraying, dextrin is preferable.
- a reinforcing agent including 40 wt % to 60 wt % of the processed starch meets the above described requirements, but because of its comparatively high concentration, it is somewhat unfavourable in respect of the penetration into the core liner.
- a surface active agent is added.
- the surface active agent a dialkyl sulphosuccinate ester, an alkylnaphthalene sulphonate ester, or the like, is preferably used.
- a dialkyl sulphosuccinate ester is preferably used because it has defoaming properties effective in preventing uneven coating on the core liner caused by foaming of the reinforcing agent when the reinforcing agent is applied by spraying.
- the amount of the surface active agent exceeds 0.1 wt %, appreciably improved mechanical strength cannot be observed; rather foaming becomes easier at the time of the spraying, so that a uniform coating on the core liner cannot be produced.
- a surface active agent is added, but at the same time the hygroscopic properties of the core liner coated with the reinforcing agent are increased.
- the water content of the corrugated cardboard is increased to, for example, 12 wt% to 13 wt%, so that its mechanical strength is reduced. Therefore, in order to increase its resistance to moisture and maintain its mechanical strength, a water resisting agent for starch is added to the reinforcing agent in an amount based on the amount of the processed starch.
- the water resisting agent for starch trimethoxy methyl melamine or the like are preferably used.
- a preferred amount of the water resisting agent for starch is 6 wt % to 10 wt% based on a solid component, i.e. the dry matter content of the processed starch.
- 6 wt % or more of the water resisting agent for starch non-reinforced corrugated cardboard which has a 70% residual strength can be increased in its residual strength.
- an amount thereof exceeding 10% no appreciable increase in the residual strength is obtained, but rather the chemical reaction of the water resisting agent with the processed starch does not take place and the water resisting agent for starch is liberated.
- Conventional product No. 1 is one produced by applying the reinforcing agent to the core liner before feeding the core liner to the corrugator, and conventional product No. 2 is one made of non-reinforced corrugated cardboard.
- composition of the reinforcing agent and the amount thereof applied were the same as in Test 2.
- composition of the adhesive agent and the amount thereof applied were the same as in Test 2.
- the results are given in Table 3.
- a corrugated core liner and both side liners are adhered together by an adhesive agent comprising an aqueous solution composed mainly of corn starch, so that even in the case where the reinforcing agent is applied to the core liner after the adhesive agent has been applied to the core liner, the reinforcing agent can penetrate sufficiently into the core liner and does not hamper the adhering of the core liner and the side liner, and consequently reinforced corrugated cardboard excellent in presusre resting strenght can be produced.
- the process of this invention can be carried out easily and simply by incorporating the reinforcing in any conventional existing corrugator.
Abstract
Description
- This invention relates to a process of manufactur- in reinforced corrugated cardboard for use in making packaging containers such as carton boxes, and more particularly relates to a process of manufacturing packaging containers made of reinforced corrugated cardboard and having improved pressure resisting properties.
- Reference will be made in the following description to the accompanying drawings in which:
- Figure 1 is a partially cut-away perspective view of a preferred reinforced corrugated cardboard packaging container produced according to the present invention;
- Figure 2 is a section view taken along line II-II of Figure 1;
- Figure 3 is a schematic diagram illustrating a preferred manufacturing process according to the present invention;
- Figure 4 is a diagram showing the results of pressure resisting tests in regard to the relationships between the pressure strength and the deformation of cardboard containers;
- Figure 5 is a perspective view of a conventional packaging container; and
- Figure 6 is a cross-sectional view of part of another conventional packaging container.
- Corrugated cardboard packaging containers are widely used for various packaging applications because they are light in weight and strong in mechanical strength. However, when the commodities to be contained therein are heavy and the corrugated cardboard packaging containers containing the commodities are piled one upon another, there is the danger that the pressure applied to the containers will be beyond the limit of the pressure resisting strength of the corrugated cardboard itself, whereby deformation or breakage of the packaging containers will take place. For this reason, as disclosed in Japanese Utility Model Laid-Open Application 52-84427, it has been proposed that the pressure resisting strength of a packaging container be improved by applying a reinforcing agent to the core of the corrugated cardboard forming the four side portions of the body of the packaging container.
- However, in use of such containers, of which side portions have been reinforced, when such containers containing heavy commodities are piled one upon another, the score line portions b thereof are crushed by pressure, as shown in Figure 6, and additionally the flaps c thereof crumple inside the side portions a, as shown in Figure 5, so that the interior dimensions of the container are decreased to such an extent that the container becomes unsuitable for reuse or is liable to break at the score line portions b. In view of the above, it has been proposed, in Japanese Utility Model Application 53-12420, that the reinforcement treatment be carried out not only on the score line portions b of the flap, but also on the sides a of the container as shown in Figures 1 and 2.
- It has been confirmed that in the manufacture of reinforced corrugated cardboard packaging containers, if reinforced corrugated cardboard manufactured by conventional manufacturing process is used, the necessary reinforcement cannot be fully attained. Thus, in a conventional process of manufacturing reinforced corrugated cardboard, a reinforcing agent is applied to a sheet of cardboard, the reinforced cardboard is then formed by pressing into a corrugated core liner, thereafter front and back liners are adhered to both faces of the liner to obtain reinforced corrugated cardboard, thereafter the reinforced corrugated cardboard is scored so that score lines are formed in the cardboard, and a packaging container is then formed.
- When the score lines are thus formed, since the reinforcing agent of the core liner has been earlier hardened by heating and drying by means of a preheater and by heating during the corrugation, the portions of the corrugated cardboard reinforced with the reinforcing agent are crushed and its structure is destroyed on forming the score lines therein by the scorer, so that when these portions are subjected to pressure when the containers are piled one upon another, these portions are bent as shown in Figure 6, and the purpose of reinforcing of the score lines is meaningless.
- The present invention provides a process of manufacturing of a reinforced corrugated cardboard type packaging container in which the score line portions are reinforced without fail and its resistance to pressure is improved to overcome the shortcomings in the prior art. According to the present invention, a corrugated core liner is adhered at one face to one side liner with an aqueous solution comprising or mainly composed of corn starch, and then the other face of the corrugated core liner is applied with an aqueous solution comprising or mainly composed of corn starch and thereafter is further applied with a reinforcing agent and thereafter the same is adhered to another side liner, and then the two side liners and the corrugated core liner are heated to form reinforced corrugated cardboard, and before completion of hardening of the reinforcing agent score lines for a packaging container are formed in the reinforced region of the reinforced corrugated cardboard.
- One example of a process of manufacturing reinforced corrugated cardboard according to this invention will now be explained with reference to Figure 3. As shown in this Figure, a sheet A for a core liner is heated and dried by a preheater 1 and is press-formed into a corrugated core liner by
corrugator 2. At the same time, there is applied thereto an adhesive agent comprising an aqueous solution mainly composed of corn starch, by a coating apparatus 3, this agent being applied to the crests of one face of the corrugated core liner A. Thereafter the corrugated core liner A is adhered to one side liner B, which is previously heated and dried by apreheater 8. Thereafter, to the corrugated core liner A, there is applied an aqueous solution mainly composed of corn starch, by acoating apparatus 4, this solution being applied to the crests of the other face of the corrugated liner A. Thereafter, a reinforcing agent D is applied by an applicator 5, partially in the region in which score lines for forming a packaging container are to be formed later. - The corrugated core liner A is then adhered to another side liner C, so that a sheet of reinforced corrugated cardboard E is formed, this corrugated cardboard being heated by a
heating plate apparatus 6 to increase the stickness of the bonding agent. - Thereafter, the reinforced corrugated cardboard E is continuously fed to a slitter-
scorer apparatus 7 and is formed with score lines F, before completion of the hardening of the reinforcing agent D applied to the reinforced corrugated cardboard E as above, and also is cut to any desired width and form. - Thus, since the reinforcing agent D has not hardened at the time of forming the score lines b in the cardboard E by the
scorer apparatus 7, the score lines are formed in the reinforced region of the reinforced corrugated cardboard without crushing and destroying the structure of that region. - The above description with reference to Figure 3 is limited to the case in which the reinforcing agent D is applied to the core liner only in the region thereof in which score lines are to be formed. However, the reinforcing agent D may be applied not only to the foregoing region thereof but also to additional regions thereof corresponding to the whole of the four side walls of the packaging container to be formed.
- The adhesive agent used in this invnetion is an aqueous solution mainly composed of corn starch. It may be gelatinized, and is usually applied to the corrugated core liner A in a viscous condition at a temperature of 70°C to 90°C.
- Also, according to this invention, the adhesive agent may be used in the form of an aqueous solution of corn starch at the time of application thereof to the corrugated core liner, and thereafter may be gelatinized by heating the core liner and both the side liners, such as by use of the
heating plate apparatus 6. - As described above, in manufacturing a packaging container made of the reinforced corrugated cardboard, according to this invention, the step of applying the reinforcing agent to the core liner is an additoinal step as compared to the steps of a conventional process of manufacturing corrugated cardboard. When applying the reinforcing agent, if the application temperature of the reinforcing agent is low, the heating time necessary for strengthening the mutual bonding of the laminate members A, B, C by the
heating plate apparatus 6 is prolonged. Particularly, when the aqueous solution mainly composed of corn starch is applied to the core liner and thereafter is gelatinized by heating for effecting the mutually bonding of the laminate members A, B, C, and when a reinforcing agent of a low temperature is applied onto the aqueous solution, the heating time has to be extended for gelatinization of the said solution. This results in a lowering in the production efficiency of reinforced corrugated cardboard. This problem can be overcome by preheating the reinforcing agent and then applying this preheated reinforcing agent to the core .liner. In particular, when the aqueous solution mainly composed of corn starch is applied to the core liner and thereafter is heated to gelatinize it, it is preferable to use a reinforcing agent which has been preheated above the gelatinization temperature of the aqueous solution. For instance, as such adhesive agents, there may be used a Stein-Hall formulation, which is of such a kind that an aqueous solution mainly composed of corn starch is heated to approximately 50°C to 60°C to gelatinize it. When this adhesive agent is used, the reinforcing agent should be preheated to about 60°C or higher, preferably to 70°C to 85°C, taking into consideration its heat loss by radiation at the time of application of the reinforcing agent to the core liner. - The invention is illustrated by the following Tests.
- In the course of manufacturing reinforced corrugated cardboard, to the core liner, while being supplied in one direction as shown in Figure 3, there was applied the foregoing aqueous solution of the adhesive agent, and then the foregoing reinforcing agent in succession and along the longitudinal direction of the core liner. One sample of reinforced corrugated cardboard was manufactured by applying a reinforcing agent previously heated to 70cC to a core liner supplied at a speed of 110 m/minute, and another sample of reinforced corrugated cardboard was manufactured by applying a reinforcing agent previously heated to 35°C to a core liner supplied at a speed of 125 m/minute. After the lapse of one hour after manufacturing the two samples, the water content of each of the two samples was measured, and the results are shown in the following Table 1. Other particular items are described below:
- It can be seen from the above that, when the reinforcing agent is previously heated to 60°C or more, preferably to 70 - 85°C, and is applied, the supply speed of the core liner to the heating plate apparatus can be increased and also the water content in the reinforced corrugated cardboard manufactured can be decreased so that the time for complete bonding of the core liner to the side liner can be reduced, resulting in an improvement in the manufacturing efficiency. ,
- It is self-evident that the reinforcing agent should not harden at the temperature of the heated plate of the
apparatus 6. If, after the reinforcing agent is applied to the core liner A, it is difficult for the adhesive agent to attach to the core liner A, so that the strength of the bond between the core liner A and the surface liner C is reduced. Therefore, it is preferable to apply the reinforcing agent D after the application of the adhesive agent to the core liner A. Accordingly, it is preferable to use a reinforcing agent able to sufficiently penetrate into the core liner A to which the adhesive agent has already been applied. Furthermore, for the purpose of partially reinforcing only the score line portions at the time of forming a packaging container, it is preferable to use a reinforcing agent which is suitable for application by spraying. - As a result of the study of reinforming agents, it has been found that a reinforcing agent comprising chemically treated or processed starch, water, a surface active agent, and a water resisting agent for starch is especially suitable as the reinforcing agent used in this invention. Preferably, such a reinforcing agent comprises 60 wt % to 40 wt % of the processed starch, 40 wt % to 60 wt % of water, 0.1 wt % or less of the surface active agent, and a water resisting agent for starch in an amount which is 6 wt % or more relative to the solid content of the processed starch.
- It is desirable that the reinforcing agent have as high concentration as possible and as low a water content as possible so as not to deform the corrugations of the core liner when the reinforcing agent is applied to the core liner, and that it have so low a coefficient of viscosity as to facilitate application thereof by spraying. This coefficient is preferably 100 cps or less (BH type viscosimeter at 20 rpm) at the temperature (20°C to 80°C) for a corrugated cardboard manufacturing process.
- In order to meet these requirements, there may be used an aqueous solution comprising 40 wt% to 60 wt% of processed starch and 60 wt % to 40 wt % of water. As for the processed starch, dextrin, oxidized starch or the like may be used, but in view of the strength of the coating film formed on the core liner by application of the reinforcing agent, and of facilitation of the application by spraying, dextrin is preferable.
- A reinforcing agent including 40 wt % to 60 wt % of the processed starch meets the above described requirements, but because of its comparatively high concentration, it is somewhat unfavourable in respect of the penetration into the core liner. In order to shorten the time for penetration into the core liner a surface active agent is added. As for the surface active agent, a dialkyl sulphosuccinate ester, an alkylnaphthalene sulphonate ester, or the like, is preferably used. In particular, a dialkyl sulphosuccinate ester is preferably used because it has defoaming properties effective in preventing uneven coating on the core liner caused by foaming of the reinforcing agent when the reinforcing agent is applied by spraying. When the amount of the surface active agent exceeds 0.1 wt %, appreciably improved mechanical strength cannot be observed; rather foaming becomes easier at the time of the spraying, so that a uniform coating on the core liner cannot be produced.
- Thus, in order to accelerate penetration of the reinforcing agent into the core liner, a surface active agent is added, but at the same time the hygroscopic properties of the core liner coated with the reinforcing agent are increased. Thus, the water content of the corrugated cardboard is increased to, for example, 12 wt% to 13 wt%, so that its mechanical strength is reduced. Therefore, in order to increase its resistance to moisture and maintain its mechanical strength, a water resisting agent for starch is added to the reinforcing agent in an amount based on the amount of the processed starch.
- As for the water resisting agent for starch, trimethoxy methyl melamine or the like are preferably used. A preferred amount of the water resisting agent for starch is 6 wt % to 10 wt% based on a solid component, i.e. the dry matter content of the processed starch. By the addition of 6 wt % or more of the water resisting agent for starch, non-reinforced corrugated cardboard which has a 70% residual strength can be increased in its residual strength. However, by the addition of an amount thereof exceeding 10%, no appreciable increase in the residual strength is obtained, but rather the chemical reaction of the water resisting agent with the processed starch does not take place and the water resisting agent for starch is liberated.
Test 2 -
- Conventional product No. 1 is one produced by applying the reinforcing agent to the core liner before feeding the core liner to the corrugator, and conventional product No. 2 is one made of non-reinforced corrugated cardboard.
- Dimensions of the corrugated cardboard containers subjected to tests:
308 mm x 464 nm x 103 mm -
- Region applied with the reinforcing agent:
- Applied onto the whole area of the four sides of the container and onto a width of 30 mm including the score lines of the flaps thereof.
-
- Conventional products No. 1 and No. 2 are the same as in
Test 2. The relationships between the loads applied to the corrugated containers and the amounts of deformation thereof in Test 3 are given in Figure 4. - As is clear from the above, according to this invention, a corrugated core liner and both side liners are adhered together by an adhesive agent comprising an aqueous solution composed mainly of corn starch, so that even in the case where the reinforcing agent is applied to the core liner after the adhesive agent has been applied to the core liner, the reinforcing agent can penetrate sufficiently into the core liner and does not hamper the adhering of the core liner and the side liner, and consequently reinforced corrugated cardboard excellent in presusre resting strenght can be produced. Further, according to this invention, the score lines for the packaging container-are scored before the reinforcing agent hardens, so that the structure of the score line region thereof is not destroyed and reinforced corrugated cardboard packaging containers having improved pressure resisting properties can be made. The process of this invention can be carried out easily and simply by incorporating the reinforcing in any conventional existing corrugator.
Claims (5)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/310,817 US4437850A (en) | 1980-10-14 | 1981-10-13 | Process of manufacturing of reinforced corrugated cardboard type packaging container |
US310817 | 1989-02-13 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0077131A2 true EP0077131A2 (en) | 1983-04-20 |
EP0077131A3 EP0077131A3 (en) | 1984-09-05 |
EP0077131B1 EP0077131B1 (en) | 1987-06-16 |
Family
ID=23204241
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP82304832A Expired EP0077131B1 (en) | 1981-10-13 | 1982-09-14 | Manufacture of packaging containers |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0077131B1 (en) |
ES (1) | ES8308952A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1992019449A2 (en) * | 1991-04-29 | 1992-11-12 | Weyerhaeuser Company | Corrugated paperboard strength enhancing process |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2592209A1 (en) | 2011-11-11 | 2013-05-15 | Bayer MaterialScience AG | Vacuum insulation panel |
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FR1222981A (en) * | 1958-04-30 | 1960-06-14 | West Virginia Pulp & Paper Co | Wax-impregnated corrugated cardboard manufacturing process |
US3189502A (en) * | 1961-03-03 | 1965-06-15 | West Virginia Pulp & Paper Com | Method of making impregnated corrugated paperboard sheets on a corrugator machine |
FR2037785A5 (en) * | 1969-03-07 | 1970-12-31 | Exxon Research Engineering Co | |
US3619342A (en) * | 1969-07-18 | 1971-11-09 | Alton Box Board Co | Corrugated fiberboard |
US3687767A (en) * | 1971-02-25 | 1972-08-29 | Alton Box Board Co | Scoring process for certain rigid-when-wet corrugated fiberboard |
CH565033A5 (en) * | 1972-12-05 | 1975-08-15 | Edkvist Ake Evald | Corrugated paper mfr - by joining smooth and corrugated webs coated with binder and impregnating agent before rolling |
JPS55142482A (en) * | 1979-04-24 | 1980-11-07 | Nec Corp | Magnetic bubble memory element |
-
1982
- 1982-09-14 EP EP82304832A patent/EP0077131B1/en not_active Expired
- 1982-10-13 ES ES516465A patent/ES8308952A1/en not_active Expired
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1222981A (en) * | 1958-04-30 | 1960-06-14 | West Virginia Pulp & Paper Co | Wax-impregnated corrugated cardboard manufacturing process |
US3189502A (en) * | 1961-03-03 | 1965-06-15 | West Virginia Pulp & Paper Com | Method of making impregnated corrugated paperboard sheets on a corrugator machine |
FR2037785A5 (en) * | 1969-03-07 | 1970-12-31 | Exxon Research Engineering Co | |
US3619342A (en) * | 1969-07-18 | 1971-11-09 | Alton Box Board Co | Corrugated fiberboard |
US3687767A (en) * | 1971-02-25 | 1972-08-29 | Alton Box Board Co | Scoring process for certain rigid-when-wet corrugated fiberboard |
CH565033A5 (en) * | 1972-12-05 | 1975-08-15 | Edkvist Ake Evald | Corrugated paper mfr - by joining smooth and corrugated webs coated with binder and impregnating agent before rolling |
JPS55142482A (en) * | 1979-04-24 | 1980-11-07 | Nec Corp | Magnetic bubble memory element |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1992019449A2 (en) * | 1991-04-29 | 1992-11-12 | Weyerhaeuser Company | Corrugated paperboard strength enhancing process |
WO1992019449A3 (en) * | 1991-04-29 | 1992-12-23 | Weyerhaeuser Co | Corrugated paperboard strength enhancing process |
US5292391A (en) * | 1991-04-29 | 1994-03-08 | Wyerhaeuser Company | Corrugated paperboard strength enhancing process |
Also Published As
Publication number | Publication date |
---|---|
EP0077131A3 (en) | 1984-09-05 |
ES516465A0 (en) | 1983-10-16 |
EP0077131B1 (en) | 1987-06-16 |
ES8308952A1 (en) | 1983-10-16 |
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