JP6084819B2 - Foam and foam manufacturing method - Google Patents

Description

  The present invention relates to a foam using a pulp fiber component, a synthetic resin component, and a starch component as an auxiliary agent, and a method for producing the same.

  Conventionally, a foam using paper as a part of a foam material has been proposed (see Patent Documents 1 and 2). Since this foam can use waste paper as a pulp fiber component, it is suitable for paper recycling. And since the foaming cell in which the foam formed many spaces is densely arrange | positioned in a foam, the passage of air can be stopped moderately and it can anticipate also as a favorable sound-absorbing material.

Japanese Patent No. 3326156 JP 2000-273800 A

  However, there is a demand for a foam that uses paper as a part of the foam material and that has even better sound absorption characteristics.

  Therefore, the present invention has been made to solve the above-described problems, and is a foam having paper as a part of a foam material, and a foam having excellent sound absorption characteristics, and a method for producing the foam. The purpose is to provide.

  The present invention is a foam comprising foam cells formed by foaming a pulp fiber component, a synthetic resin component, and a starch component as an auxiliary agent to form a large number of spaces. A foam characterized by being a block copolymer, a polypropylene resin having physical properties of a melt flow rate of 30 g / 10 min, a tensile strength of 28 MPa, and a tensile elastic modulus of 1450 MPa.

  The foamed cell is composed of a surface coating layer, a foamed cell layer, and a surface coating layer along the thickness direction. Each surface coating layer has an extremely thin thickness, and a foamed cell having a foaming density higher than that of the foamed cell layer. The densely arranged foam cell layer may have a structure in which foam cells having a foam density lower than that of each surface coating layer are densely arranged. The foamed cells are arranged between the foamed cell layers, the foamed cells having a higher density than the foamed cell layers are densely arranged, and have a partition film layer that continuously partitions the foamed cell layers. Also good. The synthetic resin component may be polypropylene resin J830HV (trade name of Prime Polymer Co., Ltd .: a kind of prime polypro).

  Another aspect of the present invention uses an extrusion molding machine provided with discharge ports arranged at intervals, and provided with a regulation frame wall for regulating a foaming region of a foam discharged from each of the discharge ports, A polypropylene resin component having a physical property of a block copolymer as a form of copolymerization with a pulp fiber component in an extruder, a melt flow rate of 30 g / 10 min, a tensile strength of 28 MPa, and a tensile elastic modulus of 1450 MPa, and a starch component as an auxiliary agent Water is supplied, the pulp fiber component, the synthetic resin component, the starch component, and water are heated and kneaded and discharged from each discharge port by pressing.

  The synthetic resin component may be polypropylene resin J830HV (trade name of Prime Polymer Co., Ltd .: a kind of prime polypro).

  According to the present invention, since the synthetic resin component has a high melt flow rate (MFR), each foam cell can swell greatly because the fluidity of the foam material is high in the foaming process, As a result, the foamed cell in which a large number of spaces are formed becomes a sparse structure. When the foam is subjected to sound vibrations, the cell structure is in a sparse state, so the vibration properties due to sound propagation in the epidermis increase, and each foam cell vibrates throughout the structure by sound due to air propagation in the foam cell, The vibration enters the space (air layer) inside the foam cell and absorbs sound. As described above, the sound absorbing characteristic is obtained in the case where the paper is made of a foam having a part of the foam material.

1 is an external perspective view of a foam according to an embodiment of the present invention. 1 shows an embodiment of the present invention and is a structural schematic diagram of a foam. FIG. 1 shows an embodiment of the present invention, (a) is a perspective view of a main part of an extrusion molding machine, and (b) is a front view of a base member. It is a figure which shows one Embodiment of this invention and shows the physical property etc. of each synthetic resin material. FIG. 6 is a characteristic diagram of sound absorption coefficient according to a reverberation chamber method for various foams according to an embodiment of the present invention. FIG. 3 is a structural schematic diagram of a foam, showing another embodiment of the present invention. The other embodiment of this invention is shown, (a) is a principal part perspective view of an extrusion molding machine, (b) is a front view of a nozzle | cap | die member.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(One embodiment)
1 to 5 show an embodiment of the present invention. As shown in FIG. 1, the foam 1A is a flat rectangular plate-like foam. The foam 1A is composed of foam cells S2 and S3 in which a paper powder component that is a pulp fiber component, a synthetic resin component, and corn starch that is a starch component as an auxiliary agent are foamed to form a large number of spaces. (See FIG. 2). As the paper powder component, used paper such as government postcards made into paper powder fiber is used.

  As the synthetic resin component, a polypropylene resin material having physical properties such that the copolymerization form is a block copolymer, the melt flow rate is 30 g / 10 min, the tensile strength is 28 MPa, and the tensile elastic modulus is 1450 MPa. Specifically, as shown in FIG. 4, J830HV (a kind of product name Prime Polypro of Prime Polymer Co., Ltd.) is used as a synthetic resin component.

  Each foam cell S2, S3 has an internal space (air layer) covered with a cell coating. The foam cells S2 and S3 have different foam densities (foaming ratios) depending on their positions, and the foam 1A is formed in the following layer structure depending on the density of the foam cells S2 and S3.

  That is, 1 A of foams are comprised from the surface film layer 2, the foam cell layer 3, and the surface film layer 2 along the thickness direction. Each surface coating layer 2 has an extremely thin thickness, and foam cells S2 having a foam density higher than the foam cell layer 3 are densely arranged. In each foam cell layer 3, foam cells S3 having a foam density lower than that of each surface coating layer 2 are densely arranged.

  Each foamed cell layer 3 is formed with a plurality of vertical partition coating layers 5 at equal intervals along the direction perpendicular to the thickness direction. Each foam cell layer 3 is divided by a longitudinal partition coating layer 5. In the vertical partition coating layer 5, foam cells S <b> 2 having a foam density higher than that of the foam cell layer 3 are densely arranged.

  Next, an extrusion molding machine 10 that manufactures the foam 1A will be described. As shown in FIG. 3A, the extrusion molding machine 10 is kneaded with an inlet (not shown) for charging each foamed material, and a kneading means (not shown) for kneading the charged foamed material. A heating means (not shown) for heating the foamed material to a high temperature, a pressing means (not shown) for pressing the foamed material, a base member 11 arranged so as to close the front end side of the pressing chamber, and the base And a regulating frame wall 20 disposed so as to surround the outside of the member 11. As shown in FIGS. 3A and 3B, the base member 11 has a plurality of discharge ports 12 arranged at equal intervals P in the horizontal direction. Each discharge port 12 is arrange | positioned in the same position with respect to the horizontal direction. The restriction frame wall 20 restricts the foaming region of the foam material discharged from the discharge port 12. The regulation frame wall 20 is a flat rectangular frame.

  Next, a method for manufacturing the foam 1A will be described. A paper powder component, a polypropylene resin material J830HV (a type of Prime Polymer, a product of Prime Polymer Co., Ltd.), corn starch as an auxiliary agent, and water are supplied into the extrusion molding machine 10. Then, the paper powder component, polypropylene resin material J830HV (a kind of Prime Polymer's trade name Prime Polypro), corn starch, and water are kneaded with heat, and this high-temperature foam material is discharged from the single-stage discharge port 12 of the base member 11. Discharge by pressing.

  Then, the water mixed in the high-temperature foam material is vaporized at the moment when it is discharged from each discharge port 12, and the paper powder component and the polypropylene resin material J830HV (trade name of Prime Polymer Co., Ltd. 1) and corn starch foam. Since the foaming is regulated by the regulation frame wall 20, the foam 1A having the regulation frame wall 20 as a cross-sectional area is continuously extruded. Each of the foamed cells S2 and S3 is appropriately foamed by the flexibility of the paper powder component and the adhesiveness of corn starch, and a space (air layer) is formed inside.

  Moreover, the foam material discharged from each discharge port 12 cannot be foamed freely, and as described above, foam formation is suppressed by the regulation frame wall 20 and foam formation is suppressed by the foam cells interfering with each other. Is done. Specifically, the foaming cell S <b> 2 located in the vicinity of the inner periphery of the regulation frame wall 20 is suppressed from being foamed by the regulation frame wall 20. Thereby, the surface film layer 2 is formed. In the foam cell S2 located near the intermediate position between the discharge ports 12 adjacent in the horizontal direction, the foam cells S2 collide (interfere) with each other, and foam formation is suppressed. Thereby, the vertical partition film layer 5 is formed. The foamed cell S3 located at the inner side of these functions only with a weak suppression force compared to the foamed cell S2. Thereby, the foam cell layer 3 is formed.

  In the above foaming process, not only the flexibility of the paper powder component and the adhesiveness of corn starch, but also the synthetic resin component has a high MRF value, the foam material exhibits high fluidity, and the MFR has a low value. Each foam cell S3 swells greatly compared to the one. Thereby, the cell structure which consists of foam cell S3 is comprised in a sparse state. Further, when the foam cell S3 swells greatly, the film thickness of each foam cell S3 becomes thin.

  In the foam 1A having such a configuration, the foam cells S2 and S3 forming a large number of spaces are arranged in a dense state, so that the vibration of the air is large and the passage of sound through the skin portion is moderately promoted. The surface coating layer 2 of the foam 1 </ b> A is appropriately vibrated by sound, and this vibration is transmitted to the foamed cell layer 3. Since the foam cell layer 3 is large and the cell structure is sparse, a portion near the skin of each foam cell S3 vibrates due to sound, and the vibration enters the air layer inside the foam cell S3. , Absorb the sound as a whole.

  In addition, since the film thickness of each foamed cell S3 is thin, the film of each foamed cell S3 is likely to vibrate, and sound is also absorbed by the vibration of the film. As described above, the foam 1A is made of a foam having paper as a part of the foam, and exhibits excellent sound absorption characteristics.

The sound absorption coefficient measurement results by the reverberation chamber method in various foams will be described below. Polypropylene resin J830HV (a product name of Prime Polymer Co., Ltd .: a kind of Prime Polypro) showed a high sound absorption rate in the range of about 1000 to 2000 Hz, compared with felt and cinsalate which are general foams. Therefore, it was confirmed that a high sound absorption characteristic is exhibited in the range of the speech intelligibility of 1000 Hz to 2000 Hz. For example, it is suitable as a sound absorbing material used in an automobile. In particular, J830HV exhibited a high sound absorption coefficient of about 0.85 at maximum in the range of 1/3 octave band center frequency of 1250 to 2000 Hz. Further, even in a high frequency band of 2000 Hz or higher, the sound absorption rate was small and the sound absorption rate was approximately 0.6 or higher.

  In addition, J715M (a product name of Prime Polymer Co., Ltd .: a type of Prime Polypro), a polypropylene resin, exhibited a high sound absorption rate in the range of approximately 1000 to 2000 Hz, compared to felt and cinsalate, which are general sound absorbing materials. However, the sound absorption rate is greatly reduced in a high frequency band of 2000 Hz or higher.

  H700 of polypropylene resin (Brand name of Prime Polymer Co., Ltd .: One type of Prime Polypro showed a slightly higher sound absorption rate in a frequency band around 2000 Hz as compared to felt and cinsalate which are general sound absorbing materials. In other frequency bands, only a low sound absorption coefficient was shown.

  As described above, in a foam having paper as a part of a foam material, the copolymer has a block copolymer, a melt flow rate of 30 g / 10 min, a tensile strength of 28 MPa, and a tensile elastic modulus of 1450 MPa. The resin exhibits excellent sound absorption performance. Further, when J830HV is used as a synthetic resin component, an antioxidant is added to J830HV, so that it does not cause oxidative deterioration at high temperatures and has good heat resistance. The foam 1A of the present embodiment is optimal for a site that requires sound absorption and heat resistance.

(Other embodiments)
6 and 7 show another embodiment of the present invention. The foam 1B is composed of foam cells S1, S2, and S3 in which a large number of spaces are formed by foaming a paper powder component that is a pulp fiber component, a synthetic resin component, and corn starch that is a starch component as an auxiliary agent. (See FIG. 7). As the paper powder component, used paper such as government postcards made into paper powder fiber is used. The synthetic resin component is the same as in the above embodiment.

  As shown in FIG. 6, the structure of the foam 1B is different from that of the embodiment. That is, the foam 1 </ b> B includes the surface coating layer 2, the foam cell layer 3, the partition coating layer 4, the foam cell layer 3, and the surface coating layer 2 along the thickness direction. Each surface coating layer 2 has an extremely thin thickness, and foam cells S2 having a foam density higher than the foam cell layer 3 are densely arranged. In each foam cell layer 3, foam cells S3 having a foam density lower than that of the partition coating layer 4 are densely arranged. In the partition coating layer 4, the foam cells S <b> 1 having a higher foam density than the foam cell layer 3 and the surface coating layer 2 are densely arranged. The partition coat layer 4 continuously partitions between the two foam cell layers 3. The partition coat layer 4 is straight in the direction orthogonal to the thickness direction and has substantially the same thickness.

  Each foamed cell layer 3 is formed with a plurality of vertical partition coating layers 5 at equal intervals along the direction perpendicular to the thickness direction. Each foam cell layer 3 is divided by a longitudinal partition coating layer 5. In the vertical partition coating layer 5, foam cells S <b> 2 having a foam density higher than that of the foam cell layer 3 are densely arranged.

  Next, an extrusion molding machine 10 that manufactures the foam 1B will be described. As shown in FIG. 7, the extrusion molding machine 10 has a plurality of discharge ports 12 and 13 that are arranged at equal intervals P in the horizontal direction on the base member 11. Has a stage. Since other configurations are the same, redundant description is omitted. The same components in the drawings are given the same reference numerals for clarification.

  This foam 1B also exhibits excellent sound absorption characteristics for the same reason as in the above embodiment.

  In addition, the foam 1 </ b> B has a partition coating layer 4 extending along the direction perpendicular to the thickness direction at an intermediate position in the thickness direction. As a result, when the vibration propagating in the foam cell layer 3 of the foam 1B reaches the partition coating layer 4, the random vibration is reset to the plane vibration in the partition coating layer 4, and then further propagates in the foam cell layer 3. Therefore, it is considered that vibration absorption is promoted by the partition coating layer 4 and further excellent sound absorption characteristics are exhibited.

(Other)
In each of the embodiments, as a synthetic resin component, polypropylene resin J830HV (a product name of Prime Polymer Co., Ltd .: a kind of prime polypro) was used. However, the present invention is a block copolymer and a melt flow rate. May be a polypropylene resin having physical properties of 30 g / 10 min, a tensile strength of 28 MPa, and a tensile elastic modulus of 1450 MPa, that is, a synthetic resin material equivalent to J830HV.

  The foam 1B of this other embodiment has the partition coating layer 4 at one place, but may have two or more partition coating layers 4. The more the partition coating layer 4 is, the better the sound absorption characteristics.

1A, 1B Foam S1, S2, S3 Foamed cell 2 Surface coating layer 3 Foamed cell layer 4 Partition coating layer 10 Extruder 12, 13 Discharge port 20 Restriction frame wall

Claims (6)

A foam comprising foam cells formed by foaming a pulp fiber component, a synthetic resin component and a starch component as an auxiliary agent,
The synthetic resin component is a foamed resin characterized in that the copolymer is a block copolymer, a polypropylene resin having physical properties of a melt flow rate of 30 g / 10 min, a tensile strength of 28 MPa, and a tensile elastic modulus of 1450 MPa. The foam according to claim 1,
The foamed cell is composed of a surface coating layer, a foamed cell layer, and a surface coating layer along the thickness direction. Each surface coating layer has an extremely thin thickness, and a foamed cell having a foaming density higher than that of the foamed cell layer. A foam characterized in that the foamed cell layers are densely arranged, and the foamed cell layers are densely arranged with foam cells having a lower foam density than the respective surface coating layers. The foam according to claim 1 or 2,
Foam characterized by being disposed between the foamed cell layers, the foamed cells having a higher density than the foamed cell layers being densely arranged, and having a partition film layer that continuously partitions the foamed cell layers. body. The foam according to any one of claims 1 to 3,
The synthetic resin component is a polypropylene resin J830HV (trade name of Prime Polymer Co., Ltd .: a kind of prime polypro), and a foamed product. Using an extrusion molding machine provided with discharge ports arranged at intervals and provided with a regulation frame wall for regulating the foaming area of the foam discharged from each of the discharge ports,
Polypropylene resin component having the physical properties of a block copolymer in the form of block copolymer, melt flow rate of 30 g / 10 min, tensile strength of 28 MPa, tensile elastic modulus of 1450 MPa and starch component as an auxiliary agent in the extruder A method for producing a foam, wherein the pulp fiber component, the synthetic resin component, the starch component, and water are heated and kneaded and discharged by pressing from the discharge ports. It is a manufacturing method of the foam according to claim 5,
The synthetic resin component is a polypropylene resin J830HV (trade name of Prime Polymer Co., Ltd .: a kind of prime polypro), and a method for producing a foam.

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