JP4739399B2 - Hollow member manufacturing method, hollow member and manufacturing apparatus thereof - Google Patents

Description

  The present invention relates to a method for producing a hollow member having a large number of independent bubble chambers, a hollow member that can be suitably produced using the method, and an apparatus for producing such a hollow member.

  Conventionally, a large number of independent bubbles are formed by forming a large number of protrusions that swell in a hollow shape on a synthetic resin film material, and by sealing another film material on the opening side of the protrusions and enclosing air. A bubble sheet formed of a chamber is widely used for various applications including a cushioning material for packaging.

Such a bubble sheet is, for example, a protrusion that bulges into a hollow shape by bringing a film material (raw material) made of synthetic resin in a molten state into contact with the outer peripheral surface of a molding roll provided with a large number of suction holes. After the part is vacuum-formed, it can be manufactured by laminating a back film (sealing material) on the opening side of the formed protrusion (see Patent Document 1, etc.).
JP-A-11-216770

By the way, as a result of intensive studies by the present inventors, when the projection is bulged into a hollow shape by vacuum forming using the molding roll as described above, the formed projection is not fed to the film material. Compared to the side wall that rises on the downstream side (entrance side) in the direction, the side wall that rises on the upstream side (outside side) tends to be thinner, and the corner on the side wall side tends to be the thinnest. (See FIGS. 9 and 10 showing comparative examples to be described later).

This is because when the film material is brought into contact with the forming roll and vacuum forming is performed, the film material 100 in a molten state having a low tensile strength is preceded before the suction hole 410 is completely closed, as shown in FIG. Then, it is drawn into the suction hole 410 from the downstream side in the feed direction approaching the suction hole 410 and is cooled from the portion that comes into contact with the inner wall surface of the suction hole 410 to lose its plasticity. This is thought to be because the part that comes in contact with the wall surface with a delay is extended more greatly.
In addition, FIG. 11 is explanatory drawing of a prior art which shows typically the process in which a projection part is formed by vacuum forming in the cross section along the feed direction of a film material, (a)-(e) in the figure. The film material 100 is stretched in the order shown.

  When manufacturing a bubble sheet, it is required to form protrusions with a certain thickness or more, and if there is a part where the required thickness is not secured, the part will break and air will leak out. There is a risk that. For this reason, if the thickness of the vacuum-formed protrusion is non-uniform, the strength design is based on the thickness of the thinnest part. Therefore, the other parts are thicker than necessary, which is not preferable for reducing the weight of the bubble sheet and reducing the amount of material resin used, for example.

  Therefore, as a result of further intensive studies by the inventors, as a resin material for forming a film material (raw material), a mixture of two or more resins having different melting points was used, and the film material was vacuum formed. Prior to the processing, the thickness distribution can be controlled so that the thickness of the protrusion formed by vacuum forming is substantially uniform along the circumferential direction by adjusting the temperature to a predetermined temperature. It has been found that it becomes easy and the present invention has been completed.

  In other words, the present invention provides a projection formed after vacuum forming a projection that bulges into a hollow shape by bringing the raw material in a molten state into contact with the outer peripheral surface of a molding roll provided with a number of suction holes. When manufacturing a hollow member having a large number of independent bubble chambers by laminating a sealing material on the opening side of the part, the thickness of the protrusion formed on the raw material is almost uniform along the circumferential direction. In addition, a method for manufacturing a hollow member capable of easily controlling the thickness distribution thereof, a hollow member that can be preferably manufactured using such a method, and an apparatus for manufacturing such a hollow member The purpose is to provide.

The method for producing a hollow member according to the present invention continuously supplies a raw material formed by extruding a resin material containing two or more kinds of resin components having different melting points from a flat die at a predetermined thickness, and the resin It has been extruded from the flat die so as to have a temperature lower than the melting point of the resin component having the highest melting point contained in the material and equal to or higher than the melting point of the resin component having the lowest melting point contained in the resin material. After adjusting the temperature of the raw material, and then vacuum-forming the raw material into a projecting portion that is brought into close contact with the outer peripheral surface of the forming roll provided with a large number of suction holes, In which the opening side of the protrusion is sealed.

In the hollow member manufactured by the above method, the thickness of the corner on the side wall that rises upstream in the feed direction of the raw material is 90 to 110% of the thickness of the corner on the side wall that rises on the downstream side. Thus, the thickness distribution of the protrusion can be controlled.

In addition, the hollow member manufacturing apparatus according to the present invention continuously supplies a raw material formed by extruding a resin material containing two or more kinds of resin components having different melting points from a flat die with a predetermined thickness. The raw material supply section of the material, and lower than the melting point of the highest melting point resin contained in the resin material, and so that the temperature is equal to or higher than the melting point of the lowest melting point resin contained in the resin material, A temperature adjusting part for adjusting the temperature of the raw material and a plurality of suction holes are provided on the outer peripheral surface, and a protrusion that bulges in a hollow shape in the raw material at the temperature is vacuum-formed. A raw material roll that has been extruded from the flat die is sent to the molding roll through the temperature control section .

  According to the present invention, the thickness distribution of the protrusions can be easily controlled when forming the protrusions that bulge into a hollow shape by vacuum forming in the raw material.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
In addition, FIG. 1 is explanatory drawing which shows the manufacturing apparatus of the hollow member which concerns on this embodiment.

First, the outline of the process of manufacturing the hollow member M having a large number of independent bubble chambers 2b by the manufacturing apparatus 1 shown in FIG.
In the manufacturing apparatus 1 shown in FIG. 1, the raw material supply unit 20 includes a flat die 21 attached to an unillustrated extruder. Then, by extruding the resin material forming the raw material 2 from the flat die 21 with a predetermined thickness, the raw material 2 formed into a film or a sheet is continuously supplied. .

  The raw material 2 supplied from the raw material supply unit 20 is sent to the forming roll 40 through the temperature control unit 50. As shown in FIG. 2, the forming roll 40 is provided with a large number of suction holes 41 on the outer peripheral surface thereof. Although not particularly illustrated, each of the suction holes 41 is connected to a vacuum pump, and vacuum forming is performed by vacuum suction in the suction holes 41. As a result, a protrusion 2 a that bulges into a hollow shape is formed on the raw material 2 that has been in close contact with the outer peripheral surface of the forming roll 40 and subjected to vacuum forming.

Here, FIG. 2 is an explanatory view showing an example of the suction hole 41 provided on the outer peripheral surface of the forming roll 40, and FIG. 2A is a perspective view showing a part of the outer peripheral surface of the forming roll 40 in perspective. FIG. FIG. 2B is a cross-sectional view corresponding to the AA cross section of FIG. 2A showing an example in which the suction hole 41 is formed in a columnar shape, and FIG. It is sectional drawing equivalent to the AA cross section which shows the example formed in truncated cone shape.
In FIG. 2A, the direction of rotation of the forming roll 40 is indicated by an arrow.

  The temperature control unit 50 is installed to adjust the temperature of the raw material 2 before the raw material 2 is subjected to vacuum forming. In the example shown in FIG. 1, the cooling roll 51 and the first heating roll 52 are provided. , And a second heating roll 53. Thereby, after the raw material raw material 20 in the molten state supplied from the raw material raw material supply unit 20 is cooled and solidified by the cooling roll 51, the first heating roll 52 and the second heating roll 53 perform predetermined processing. Sequentially heated to reach temperature.

  At this time, the cooling roll 51 is set so as to have a temperature of about room temperature (about 25 ° C.), and the first heating roll 52 and the second heating roll 53 are raised in this order to be cooled and solidified once. It is preferable that the temperature of the raw material 2 is gradually increased. As will be described later, the resin material forming the raw material 2 includes two or more resin components having different melting points. For example, the first heating roll 52 is included in the resin material forming the raw material 2. The temperature is set lower than the melting point of the resin component having the lowest melting point, and the setting temperature of the second heating roll 53 is set to a higher target temperature (or a slightly higher temperature than the target temperature). Can do. If it does in this way, it can prevent that the raw material raw material 2 is heated suddenly, melts and breaks, etc., and it interferes with the feeding of the raw material raw material 2.

Here, before the raw material 2 is subjected to vacuum forming, how to adjust the temperature of the raw material 2 will be described later, but the configuration of the temperature control unit 50 is not limited to the example shown in FIG. . As long as the temperature of the raw material 2 can be adjusted to the target temperature, other cooling means such as an air-cooling cooling means using an air knife may be used instead of the cooling roll 51, for example. Moreover, it can replace with both or any one of the 1st heating roll 52 and the 2nd heating roll 53, and can also utilize other heating means, such as a heating means by the radiant heat from a resistance heater.
Furthermore, in the example shown in FIG. 1, the raw material 2 extruded from the flat die 21 is once cooled and solidified by the cooling roll 51, and then gradually heated by the first heating roll 52 and the second heating roll 53. However, the heating means such as a heating roll can be omitted, and the raw material 2 can be adjusted to the target temperature only by the cooling means such as a cooling roll.

Specifically, modifications as shown in FIGS. 3 and 4 are possible. That is, in the example shown in FIG. 3, the temperature adjustment unit 50 includes a first cooling roll 54 and a second cooling roll 55 as cooling means. The raw material 2 extruded from the flat die 21 is gradually cooled while being fed in the order of the first cooling roll 54 and the second cooling roll 55 so as to reach a target temperature. Moreover, in the example shown in FIG. 4, the temperature control part 50 is provided with the air knife 56 as a cooling means. Then, air is blown onto the raw material 2 extruded from the flat die 21 to cool it, thereby achieving a target temperature.
Note that the example shown in FIG. 1 is most preferable from the viewpoint of easy temperature adjustment of the raw material 2, and the example shown in FIG. 3 is the next preferable, and the example shown in FIG. 4 is the next preferable. .

  Thus, the sealing material 3 is laminated | stacked on the opening side of the projection part 2a in the raw material 2 in which the projection part 2a was formed by vacuum forming in the state closely_contact | adhered to the forming roll 40. FIG. In the example shown in FIG. 1 and the like, the sealing material 3 is formed from a sealing material supply unit 30 including a flat die 31 attached to an unillustrated extruder, and is formed into a predetermined thickness, while being in close contact with the forming roll 40. Between the opposite side 2 and the pressing roll 60, the molten state is continuously supplied. And it is laminated and integrated with the raw material 2 by heat fusion.

  As a result, air is enclosed in the protrusions 2 a formed on the raw material 2 and a hollow member M having a large number of independent bubble chambers 2 b is manufactured. It peels from the forming roll 40 and is wound up on a winding roll (not shown).

  In manufacturing the hollow member M having a large number of independent bubble chambers 2b as described above, as the resin material for forming the sealing material 3, for example, a polyolefin resin such as a polypropylene resin or a polyethylene resin is used alone. Or a mixture of two or more. Although the specific example is shown below, it can be said that various resin materials can be used according to a use, considering heat fusibility with raw material 2 without being limited to polyolefin resin. Not too long.

  Specific examples of the polypropylene resin include a propylene homopolymer or a copolymer of propylene and another olefin. Other olefins copolymerized with propylene include α-olefins such as ethylene, butene-1, isobutylene and pentene-1, and copolymers with these other olefins include random copolymers, block Any of copolymers may be used.

  Specific examples of the polyethylene resin include high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), linear ultra-low density polyethylene (LVLDPE), ethylene- A vinyl acetate copolymer etc. can be illustrated.

  Moreover, as resin material which forms the raw material raw material 2, although the same resin as having mentioned above can be used, 2 or more types of resin from which melting | fusing point differs are selected arbitrarily, and what mixed these is used. At this time, the resin is not limited to the same type, and for example, a polypropylene resin and a polyethylene resin may be mixed and used.

  In this embodiment, as described above, the temperature of the raw material 2 is adjusted in the resin material prior to vacuum forming the protrusion 2a on the raw material 2. The temperature is adjusted to be lower than the melting point of the resin component having the highest melting point and higher than the melting point of the resin component having the lowest melting point contained in the resin material.

In this way, when the protrusion 2a is formed on the raw material 2 by vacuum forming, the thickness distribution is controlled so that the thickness of the protrusion 2a is substantially uniform along the circumferential direction. It becomes easy. This is because, by adjusting the temperature of the raw material 2 as described above, the tensile strength of the raw material 2 at the time of being subjected to vacuum forming is appropriately increased, so that the material is formed before the suction hole 41 is completely blocked. The raw fabric 2 is prevented from being drawn into the suction hole 41, and the raw material fabric 2 is completely drawn into the suction hole 41 after the raw material fabric 2 has closed the suction hole 41 as shown in FIG. It is presumed that
In addition, FIG. 5 is explanatory drawing which shows typically the process in which the projection part 2a is formed by vacuum forming in the cross section along the feed direction of the raw material fabric 2, and (a)-(e) in the figure The raw material fabric 2 is stretched in the order shown.

  As described above, in the present embodiment, when the protrusion 2a is vacuum-formed on the raw material 2, the raw material 2 is evenly drawn into the suction holes 41, so that the protrusion It is considered that the thickness distribution of the portion 2a can be controlled. In controlling the thickness distribution of the protrusion 2a in this way, more specifically, the side wall that rises on the upstream side in the feed direction of the raw material 2 has a wall thickness that rises on the downstream side. It is possible to control the wall thickness distribution of the protrusion 2a so that it falls within the range of 90 to 110% of the wall thickness of the side corner.

  Further, in controlling the thickness distribution of the protrusion 2a in this way, the resin component having the highest melting point contained in the resin material forming the raw material 2 is mixed at a ratio of 10 to 50% by weight. Is more preferable, and 15 to 30% by weight is more preferable. If it is less than this range, the ratio of the low melting point resin component will increase, so the tensile strength of the raw material 2 during the vacuum forming will also be relatively lowered, and the meat of the protrusion 2a This is not preferable because the thickness distribution tends to be insufficiently controlled. Moreover, if it exceeds such a range, the tensile strength of the raw material 2 at the time of vacuum forming tends to be too high, and there is a possibility that the formation of the protruding portion 2a may be hindered.

  In selecting two or more resins having different melting points, the difference between the melting point of the resin component having the highest melting point and the melting point of the resin component having the lowest melting point is preferably in the range of 5 to 50 ° C. More preferably, it exists in the range of 10-30 degreeC. If it is less than this range, the range in which the temperature of the raw material 2 can be adjusted becomes narrow, and adjustment tends to be difficult. Moreover, when it exceeds such a range, it is not preferable because the resin material tends not to be kneaded well in the extruder.

  The melting point of the resin material can be determined as a temperature indicating an endothermic peak in differential scanning calorimetry according to JIS K7121, and differential scanning calorimetry is performed for a resin material containing two or more resin components having different melting points. In the obtained DSC curve, the temperature indicating the endothermic peak appearing on the highest temperature side is defined as “the melting point of the resin component having the highest melting point”, and the temperature indicating the endothermic peak appearing on the lowest temperature side is defined as the “melting point of the resin component having the lowest melting point”. "

  Although the present invention has been described with reference to the preferred embodiment, it is needless to say that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. .

For example , the thicknesses of the raw material 2 and the sealing material 3 can be appropriately changed according to the application. However, when forming the protrusion 2a by subjecting the raw material 2 to vacuum forming, the thickness of the protrusion 2a tends to be non-uniform as the thickness of the raw material 2 decreases. For this reason, this invention is especially effective when the thickness of the raw material raw material 2 is comparatively thin 15-500 micrometers.

  Next, the present invention will be described in more detail with reference to specific examples.

[Example 1]
High-density polyethylene (melting point 125 ° C.): 30% by weight, low-density polyethylene (melting point 109 ° C.): 40% by weight, linear low-density polyethylene (melting point 111 ° C.): 30% by weight are mixed into the raw material 2 The resin material to be formed is the same as the resin material for forming the sealing material 3. Then, while the resin material is melt kneaded and extruded at a temperature of about 230 ° C. by the apparatus shown in FIG. 1, the raw material 2 has a thickness of 34 μm, the sealing material 3 has a thickness of 20 μm, and a basis weight of 50 g / m ^2. Thus, a hollow member (bubble sheet) M was manufactured at a line speed of 40 m / min.

  At this time, the respective temperatures were set such that the cooling roll 51 was 25 ° C., the first heating roll 52 was 100 ° C., and the second heating roll 53 was 120 ° C. Thereby, the raw material raw material 2 once cooled and solidified by the cooling roll 51 is lower than the melting point (125 ° C.) of the high-density polyethylene which is the resin component having the highest melting point contained in the resin material, and has the highest melting point. The temperature was adjusted to 120 ° C. which is equal to or higher than the melting point (109 ° C.) of low-density polyethylene, which is a low resin component, and then reached the forming roll 40.

Further, on the outer peripheral surface of the forming roll 40, a large number of suction holes 41 arranged in a staggered manner as shown in FIG. 2A are provided, and the pitch P1 along the feed direction of the raw material 2 is 10 mm. The pitch P2 along the direction orthogonal to the opposite feed direction was set to 11.5 mm. Each suction hole 41 is formed in a columnar shape (see FIG. 2B), and the dimensions are such that the diameter φD is 10 mm, the depth d is 4 mm, and the corner portion R on the bottom side of the suction hole 41 is 1 mm. .
Note that when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

About the hollow member (bubble sheet | seat) M manufactured as mentioned above, the outline of the cross section of the projection part 2a formed in the raw material raw material 2 is shown in FIG . The cross section shown in FIG. 6 is a cross section that passes through the center of the protrusion 2 a along the feed direction of the raw material 2. As shown in FIG. 6 , in the present embodiment, the thickness of the protrusion 2a is substantially the same on the side wall side that rises downstream in the feed direction of the raw material 2 and the side wall side that rises on the upstream side. It was. Furthermore, the thickness distribution of the protrusion 2a is substantially uniform along the circumferential direction, and the thickness of each part along the circumferential direction of the protrusion 2a is substantially constant.

Specifically, the thickness T of the material raw 2 is taken as 100%, and the thickness T ₁ of the side walls rising to the downstream side of the material raw second feeding direction, the thickness of the side wall standing up in the upstream side T ₂ was both about 50%, and the thickness of the side wall of the protrusion 2a showed substantially the same value along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 36%.

[Example 2]
Polypropylene homopolymer (melting point 160 ° C.): 20% by weight, ethylene-propylene random copolymer (ethylene 8% by weight, melting point 125 ° C.): 80% by weight are mixed into a resin material forming the raw material 2 and sealed. The resin material forming the stopper 3 was also the same. Then, with the apparatus shown in FIG. 1, these resin materials are melt-kneaded and extruded at a temperature of about 250 ° C., so that the raw material 2 has a thickness of 32 μm, the sealing material 3 has a thickness of 18 μm, and a basis weight of 50 g / m ^2. Thus, a hollow member (bubble sheet) M was manufactured at a line speed of 40 m / min.

  At this time, the respective temperatures were set such that the cooling roll 51 was 25 ° C., the first heating roll 52 was 120 ° C., and the second heating roll 53 was 145 ° C. Thereby, the raw material raw material 2 once cooled and solidified by the cooling roll 51 is lower than the melting point (160 ° C.) of the polypropylene homopolymer which is the resin component having the highest melting point contained in the resin material, and has the highest melting point. The temperature was adjusted to 140 ° C., which is higher than the melting point (125 ° C.) of the ethylene-propylene random copolymer, which is a low resin component, before reaching the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 80 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 70 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side walls that rise in the upstream side are both about 50%, the thickness of the side wall of the protruding portion 2a, along the circumferential direction Almost the same value. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a was about 40%.

[Example 3]
Ethylene-propylene random copolymer (ethylene 5% by weight, melting point 135 ° C.): 70% by weight, low density polyethylene (melting point 109 ° C.): 30% by weight is mixed into a resin material to form the raw material 2 and sealed The resin material forming the stopper 3 was also the same. Then, while the resin material is melt kneaded and extruded at a temperature of about 240 ° C. by the apparatus shown in FIG. 1, the raw material 2 has a thickness of 31 μm, the sealing material 3 has a thickness of 20 μm, and a basis weight of 50 g / m ^2. Thus, a hollow member (bubble sheet) M was manufactured at a line speed of 40 m / min.

  At this time, the respective temperatures were set such that the cooling roll 51 was 25 ° C., the first heating roll 52 was 110 ° C., and the second heating roll 53 was 128 ° C. Thereby, the raw material raw material 2 once cooled and solidified by the cooling roll 51 is lower than the melting point (135 ° C.) of the ethylene-propylene random copolymer which is the resin component having the highest melting point contained in the resin material, In addition, the temperature is adjusted to 125 ° C. which is equal to or higher than the melting point (109 ° C.) of the low density polyethylene, which is the resin component having the lowest melting point, before reaching the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side wall of the protruding portion 2a which rises in the upstream side are both about 50%, the thickness of the side wall of the protruding portion 2a, Almost the same value was shown along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a was about 40%.

[Example 4]
With the apparatus shown in FIG. 3, while the same resin material as in Example 1 was melt kneaded and extruded at a temperature of about 230 ° C., the thickness of the raw material 2 was 34 μm, the thickness of the sealing material 3 was 20 μm, and the basis weight was 50 g / m ² . A hollow member (bubble sheet) M was manufactured at a line speed of 40 m / min.

  At this time, each temperature was set so that the 1st cooling roll 54 might be 155 degreeC, and the 2nd cooling roll 55 might be 125 degreeC. Thereby, the raw material 2 is lower than the melting point (125 ° C.) of the high-density polyethylene which is the resin component having the highest melting point contained in the resin material, and the low-density polyethylene which is the resin component having the lowest melting point. The temperature was adjusted to 120 ° C. above the melting point (109 ° C.), and then reached the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side wall of the protruding portion 2a which rises in the upstream side are both about 50%, the thickness of the side wall of the protruding portion 2a, Almost the same value was shown along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 45%.

[Example 5]
While the same resin material as in Example 1 was melt-kneaded and extruded at a temperature of about 230 ° C. by the apparatus shown in FIG. 4, the thickness of the raw material 2 was 34 μm, the thickness of the sealing material 3 was 20 μm, and the basis weight was 50 g / m ² . A hollow member (bubble sheet) M was manufactured at a line speed of 35 m / min.

  At this time, air set at 40 ° C. was blown from the air knife 56 at an air volume of 150 L / min. Thereby, the raw material 2 is lower than the melting point (125 ° C.) of the high-density polyethylene which is the resin component having the highest melting point contained in the resin material, and the low-density polyethylene which is the resin component having the lowest melting point. The temperature was adjusted to 120 ° C. above the melting point (109 ° C.), and then reached the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side wall of the protruding portion 2a which rises in the upstream side are both about 50%, the thickness of the side wall of the protruding portion 2a, Almost the same value was shown along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 45%.

[Example 6]
While the same resin material as in Example 2 was melt-kneaded and extruded at a temperature of about 250 ° C. by the apparatus shown in FIG. 3, the thickness of the raw material 2 was 32 μm, the thickness of the sealing material 3 was 18 μm, and the basis weight was 50 g / m ² . A hollow member (bubble sheet) M was manufactured at a line speed of 40 m / min.

  At this time, each temperature was set so that the 1st cooling roll 54 might be 170 degreeC, and the 2nd cooling roll 55 might be 145 degreeC. Thereby, the raw material 2 is lower than the melting point (160 ° C.) of the polypropylene homopolymer which is the resin component having the highest melting point contained in the resin material, and ethylene-propylene which is the resin component having the lowest melting point. The temperature was adjusted to 140 ° C., which is higher than the melting point (125 ° C.) of the random copolymer, before reaching the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 80 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 70 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side wall of the protruding portion 2a which rises in the upstream side are both about 45%, the thickness of the side wall of the protruding portion 2a, Almost the same value was shown along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 45%.

[Example 7]
While the same resin material as in Example 3 was melt-kneaded and extruded at a temperature of about 240 ° C. by the apparatus shown in FIG. 3, the thickness of the raw material 2 was 31 μm, the thickness of the sealing material 3 was 20 μm, and the basis weight was 50 g / m ² . A hollow member (bubble sheet) M was manufactured at a line speed of 40 m / min.

  At this time, each temperature was set so that the 1st cooling roll 54 might be 170 degreeC, and the 2nd cooling roll 55 might be 145 degreeC. Thereby, the raw material 2 is lower than the melting point (135 ° C.) of the ethylene-propylene random copolymer which is the resin component having the highest melting point contained in the resin material and is the resin component having the lowest melting point. The temperature was adjusted to 125 ° C., which is equal to or higher than the melting point (109 ° C.) of a certain low density polyethylene, and then reached the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side wall of the protruding portion 2a which rises in the upstream side are both about 47%, the thickness of the side wall of the protruding portion 2a, Almost the same value was shown along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 45%.

[Example 8]
While melt-kneading and extruding the same resin material as in Example 2 at a temperature of about 250 ° C. using the apparatus shown in FIG. 4, the thickness of the raw material 2 is 32 μm, the thickness of the sealing material 3 is 18 μm, and the basis weight is 50 g / m ² . A hollow member (bubble sheet) M was manufactured at a line speed of 35 m / min.

  At this time, air set at 40 ° C. was blown from the air knife 56 at an air volume of 200 L / min. Thereby, the raw material 2 is lower than the melting point (160 ° C.) of the polypropylene homopolymer which is the resin component having the highest melting point contained in the resin material, and ethylene-propylene which is the resin component having the lowest melting point. The temperature was adjusted to 140 ° C., which is higher than the melting point (125 ° C.) of the random copolymer, before reaching the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 80 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 70 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side wall of the protruding portion 2a which rises in the upstream side are both about 47%, the thickness of the side wall of the protruding portion 2a, Almost the same value was shown along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 45%.

[Example 9]
While the same resin material as in Example 3 was melt-kneaded and extruded at a temperature of about 240 ° C. by the apparatus shown in FIG. 4, the thickness of the raw material 2 was 31 μm, the thickness of the sealing material 3 was 20 μm, and the basis weight was 50 g / m ² . A hollow member (bubble sheet) M was manufactured at a line speed of 40 m / min.

  At this time, air set at 40 ° C. was blown from the air knife 56 at an air volume of 180 L / min. Thereby, the raw material 2 is lower than the melting point (135 ° C.) of the ethylene-propylene random copolymer which is the resin component having the highest melting point contained in the resin material and is the resin component having the lowest melting point. The temperature was adjusted to 125 ° C., which is equal to or higher than the melting point (109 ° C.) of a certain low density polyethylene, and then reached the forming roll 40.

  In addition, the same thing as Example 1 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

In the hollow member (bubble sheet) M manufactured as described above, the protrusion 2a has a raw material 2 when the thickness T of the raw material 2 is 100% as in the example shown in FIG. the thickness T ₁ of the side walls rising to the downstream side of the feeding direction, the thickness T ₂ of the side wall of the protruding portion 2a which rises in the upstream side are both about 50%, the thickness of the side wall of the protruding portion 2a, Almost the same value was shown along the circumferential direction. Further, the thickness T ₄ of the corner on the side wall side rising to the downstream side in the feed direction of the raw material 2 and the thickness T ₅ of the side corner rising to the upstream side are both about 25%, The thickness of this part also showed substantially the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 45%.

[ Example 10 ]
The apparatus shown in FIG. 1 melts and kneads the same resin material as in Example 1 at a temperature of about 230 ° C., and extrudes the raw material 2 with a thickness of 25 μm, the sealing material 3 with a thickness of 20 μm, and a basis weight of 41.5 g / m. ^A hollow member (bubble sheet) M was produced at a line speed of 40 m / min.

  At this time, the respective temperatures were set such that the cooling roll 51 was 25 ° C., the first heating roll 52 was 100 ° C., and the second heating roll 53 was 120 ° C. Thereby, the raw material raw material 2 once cooled and solidified by the cooling roll 51 is lower than the melting point (125 ° C.) of the high-density polyethylene which is the resin component having the highest melting point contained in the resin material, and has the highest melting point. The temperature was adjusted to 120 ° C. which is equal to or higher than the melting point (109 ° C.) of low-density polyethylene, which is a low resin component, and then reached the forming roll 40.

Further, on the outer peripheral surface of the forming roll 40, a large number of suction holes 41 arranged in a staggered manner as shown in FIG. 2A are provided, and the pitch P1 along the feed direction of the raw material 2 is 10 mm. The pitch P2 along the direction orthogonal to the opposite feed direction was set to 11.5 mm. Each suction hole 41 is formed in the shape of a truncated cone (see FIG. 2 (c)), and the dimensions are as follows: the diameter φD of the opening is 10 mm, the diameter φD _b of the bottom is 8.5 mm, and the depth d is 4 mm. The corner R on the bottom side of the hole 41 was 1 mm.
Note that when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

About the hollow member (bubble sheet | seat) M manufactured as mentioned above, the outline of the cross section of the projection part 2a formed in the raw material raw material 2 is shown in FIG . The cross section shown in FIG. 7 is a cross section that passes through the center of the protrusion 2 a along the feed direction of the raw material 2. As shown in FIG. 7 , in the present embodiment, the thickness of the protrusion 2a is approximately equal between the side wall side that rises obliquely on the downstream side in the feed direction of the raw material 2 and the side wall side that rises diagonally on the upstream side. It was the same wall thickness. Furthermore, the thickness distribution of the protrusion 2a is substantially uniform along the circumferential direction, and the thickness of each part along the circumferential direction of the protrusion 2a is substantially constant.
Specifically, the thickness T of the material raw 2 is taken as 100%, and the thickness T ₁ of the side walls rising to the downstream side of the material raw second feeding direction, the thickness of the side wall standing up in the upstream side T ₂ are both about 55%, the thickness of the side wall of the protruding portion 2a showed almost the same values in the circumferential direction. Further, a material raw second feeding direction of the downstream corner thickness T ₄ of the side wall which rises obliquely, the thickness T ₅ of the corner of the side wall which rises obliquely in the upstream side are both about 35 %, And the thickness of this part also showed almost the same value along the circumferential direction.
Further, the thickness T ₃ approximately in the middle of the top surface of the protruding portion 2a is about 42%.

[Comparative Example 1]
Except for using a device as shown in Figure 8, it was produced hollow member (bubble wrap) M ₀ under the same conditions as in Example 1.
At this time, the raw material 102 is estimated to reach the forming roll 40 at a temperature of about 200 ° C., which is higher than the melting point (125 ° C.) of high-density polyethylene, which is the resin component having the highest melting point contained in the resin material. The
The apparatus shown in FIG. 8 corresponds to the apparatus shown in FIG. 1 with the temperature control unit 50 removed, and the same reference numerals are given to the same components as those shown in FIG. Omitted.

For hollow member (bubble wrap) M ₀ prepared in Comparative Example 1 shows a schematic cross-section of the protrusion 102a formed on the material raw 102 in FIG. The cross section shown in FIG. 9 is a cross section that passes through the center of the protrusion 102 a along the feed direction of the raw material 102. As shown in FIG. 9 , the protrusion 102a in this comparative example is thinner on the side wall rising on the upstream side than on the side wall rising on the downstream side in the feed direction. ₀ is taken as 100%, the thickness T ₁₀ of the side walls that rise on the downstream side of the feeding direction about 61%, the thickness T ₂₀ of the side wall standing up in the upstream side was about 43%. Moreover, about 31% the thickness T ₄₀ of the corner portion of the side wall that rises on the downstream side of the feeding direction, the thickness T ₅₀ of the corner portion of the side wall standing up in the upstream side is about 19%, of the side wall The corner was the thinnest.
Further, substantially at the center of the wall thickness _{T 30} the top surface of the protruding portion 102a is about 40%.

[Comparative Example 2]
The apparatus shown in FIG. 8 melts and kneads the same resin material as in Example 1 at a temperature of about 230 ° C., and extrudes the raw material 102 with a thickness of 25 μm, the sealing material 3 with a thickness of 20 μm, and a basis weight of 41.5 g / m. ^A hollow member (bubble sheet) M ₀ was produced at a line speed of 40 m / min.
At this time, the raw material 102 is estimated to reach the forming roll 40 at a temperature of about 200 ° C., which is higher than the melting point (125 ° C.) of high-density polyethylene, which is the resin component having the highest melting point contained in the resin material. The

In addition, the same thing as Example 10 was used for the forming roll 40. FIG. Further, when the raw material 2 was subjected to vacuum forming, the temperature of the forming roll 40 was set to 75 ° C., and the set temperatures of the pressing roll 60 and the peeling roll 70 were set to 65 ° C. and 25 ° C., respectively.

For hollow member (bubble wrap) M ₀ prepared in Comparative Example 1 shows a schematic cross-section of the protrusion 102a formed on the material raw 102 in FIG. 10. The cross section shown in FIG. 10 is a cross section that passes through the center of the protrusion 102 a along the feed direction of the raw material 102. As shown in FIG. 10 , the protrusion 102a in this comparative example is thinner on the wall that rises obliquely upstream than the side wall that rises obliquely downstream in the feed direction. the thick T ₀ is taken as 100%, about 61% wall thickness T ₁₀ of the side wall that rises obliquely to the downstream side of the feeding direction, the thickness T ₂₀ of the side wall that rises in the upstream met about 43% It was. Further, the thickness T ₄₀ of the corner on the side wall rising obliquely downstream in the feed direction is about 31%, and the thickness T ₅₀ of the corner on the side wall rising obliquely upstream is about 19%. The corner on the side wall was the thinnest.
Further, substantially at the center of the wall thickness _{T 30} the top surface of the protruding portion 102a is about 40%.

  The present invention provides a hollow member having a large number of independent bubble chambers such as a bubble sheet used for various applications in addition to a cushioning material for packaging.

It is explanatory drawing which shows embodiment of the manufacturing apparatus of the hollow member which concerns on this invention. It is explanatory drawing which shows an example of the suction hole provided in the outer peripheral surface of a forming roll. It is explanatory drawing which shows the modification of embodiment of the manufacturing apparatus of the hollow member which concerns on this invention. It is explanatory drawing which shows the other modification of embodiment of the manufacturing apparatus of the hollow member which concerns on this invention. It is explanatory drawing which shows typically the process in which a projection part is formed by vacuum forming. It is explanatory drawing which shows the cross section which passes along the center of the projection part along the feed direction of a raw material fabric in Examples 1-9 . In Example 10 , it is explanatory drawing which shows the cross section which passes along the center of the projection part along the feed direction of a raw material raw material. It is explanatory drawing which shows an example of the manufacturing apparatus used by the comparative example. It is explanatory drawing which shows the cross section which passes along the center of the projection part along the feed direction of a raw material fabric in the comparative example 1. FIG. It is explanatory drawing which shows the cross section which passes along the center of the projection part along the feed direction of a raw material fabric in the comparative example 2. It is explanatory drawing of the prior art which shows typically the process in which a projection part is formed by vacuum forming.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 2 Raw material 2a Protrusion part 2b Bubble chamber 3 Sealing material 20 Raw material supply part 21 Flat die 40 Forming roll 41 Suction hole 50 Temperature control part 60 Pressing roll M Hollow member

Claims (6)

A raw material formed by extruding a resin material containing two or more resin components having different melting points from a flat die at a predetermined thickness is continuously supplied.
It has been extruded from the flat die so that the temperature is lower than the melting point of the resin component having the highest melting point contained in the resin material and equal to or higher than the melting point of the resin component having the lowest melting point contained in the resin material. After adjusting the temperature of the raw material, after vacuum forming a protrusion that bulges in a hollow shape in close contact with the outer peripheral surface of the forming roll provided with a number of suction holes,
A method for producing a hollow member, wherein a sealing material is laminated to seal the opening side of the protrusion.   The manufacturing method of the hollow member of Claim 1 which adjusts the temperature of the said raw material raw material by cooling and solidifying the said raw material raw material extruded from the said flat die, and then heating so that it may become the said temperature.   The manufacturing method of the hollow member of Claim 1 which adjusts the temperature of the said raw material raw material extruded from the said flat die so that it may become the said temperature with a cooling means.   The manufacturing method of the hollow member as described in any one of Claims 1-3 which mixes the resin component with the highest melting | fusing point contained in the resin material which forms the said raw material fabric in the ratio of 10 to 50 weight%.   The difference between the melting point of the resin component having the highest melting point contained in the resin material forming the raw material and the melting point of the resin component having the lowest melting point is 5 to 50 ° C. The manufacturing method of the hollow member of Claim 1. A raw material supply section for continuously supplying a raw material formed by extruding a resin material containing two or more kinds of resin components having different melting points from a flat die at a predetermined thickness;
The temperature of the raw material is adjusted so that the temperature is lower than the melting point of the highest melting point resin contained in the resin material and equal to or higher than the melting point of the lowest melting point resin contained in the resin material. A temperature control unit to
A plurality of suction holes are provided on the outer peripheral surface, and includes a forming roll for vacuum forming a protrusion that bulges in a hollow shape in the raw material at the temperature,
The apparatus for producing a hollow member, wherein the raw material extruded from the flat die is sent to the forming roll through the temperature control section.

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