JP4633526B2 - Biodegradable resin product, molding method thereof and molding apparatus - Google Patents

Description

  The present invention relates to a resin product such as a container made from a biodegradable resin such as a plant-derived resin, a molding method thereof, and a molding apparatus.

In the prior art, containers made of biodegradable resins have problems with respect to water permeability, breath resistance, impact resistance, and chemical resistance.
In order to solve these problems of biodegradable resins, the following have been proposed. That is, an invention has been proposed in which a plastic product that is biodegradable in a short period of time can be obtained by forming the inner layer of the container with a polyolefin resin and the outer layer with a biodegradable resin. This is a biodegradable plastic product characterized in that, in a laminated plastic product having at least an inner layer and an outer layer, 50% by mass or more of the constituent components of the outer layer is a biodegradable resin, and the inner layer is a polyolefin resin ( For example, see Patent Document 1).

  Another proposal is a multilayer container comprising a layer made of polylactic acid having a surface gloss, excellent oxygen barrier properties and moisture barrier properties, and having no content coloring or the like, and excellent content resistant properties. (For example, refer to Patent Document 2). That is, in an aliphatic polyester multilayer container containing a barrier resin as an intermediate layer, containing at least one aliphatic polyester resin in the inner and outer layers, and having an adhesive resin layer interposed between the intermediate layer and the inner and outer layers, The aliphatic polyester resin of the layer is polylactic acid, and the intermediate layer is at least one resin consisting of a resin selected from the group consisting of an ethylene / vinyl alcohol copolymer, a cyclic olefin copolymer, and a cyclohexanedimethanol-modified aromatic polyester. It is an aliphatic polyester multilayer container characterized by containing a layer.

  On the other hand, as an apparatus for forming a multilayer divided container having an outer layer having shape retention and an inner layer that can be peeled from the outer layer, a part of the first molding material supply channel for one layer forming the container There has been proposed a multi-layer divided container molding device characterized by providing a second molding material supply port for supplying a second molding material having an adhesive action with the first molding material (for example, see Patent Document 3). ).

JP 2001-225430 A JP 2001-347623 A JP 2004-123174 A

However, although the biodegradability is maintained in the plastic container disclosed in Cited Document 1, there is still room for improvement with respect to water permeability, air resistance, impact resistance, and chemical resistance.
In the multilayer container disclosed in the cited document 2, a barrier resin is used as an intermediate layer, an aliphatic polyester resin is contained in the inner and outer layers, and an adhesive resin layer is interposed between the intermediate layer and the inner and outer layers. However, the adhesiveness of the adhesive resin layer is weak. Therefore, the product embodying this invention is not practical due to lack of adhesion.
In the multilayer divided container forming apparatus disclosed in the cited document 3, a container which is a double layer and partially a triple layer can be formed. However, if the entire structure is a triple layer structure, there is a problem that the adhesion between the layers is weak and a practical container cannot be formed. Furthermore, in consideration of weak adhesiveness, if the intermediate layer is intermittently formed and the inner layer and the outer layer are partially continuous, the inner layer and the outer layer can be partially integrated, and in terms of strength. There is no practical problem. However, the barrier function of the part where the inner layer and the outer layer are partially connected is lowered, and the action as a container is inferior.

(Object of invention)
The present invention has been made in view of the above-described problems of the biodegradable resin product of the prior art or the molding apparatus thereof, and includes a biodegradable resin material containing a large proportion of the material used. An object is to provide a product, a molding method thereof, and a molding apparatus.
Another object of the present invention is to provide a biodegradable resin product having a sufficient barrier property and having a strong bonding strength between the inner layer and the outer layer to such an extent that there is no practical problem, and a molding method and molding apparatus therefor.

  In the first invention, substantially the entire wall portion is made of a biodegradable resin material, and includes at least two barrier layers in the wall portion, and each barrier layer includes a plurality of strip portions extending in the resin material flow direction. The two barrier layers are formed so as to be spaced apart from each other, and are formed such that the interval between the strip portions of one of the barrier layers overlaps the strip portion of the other barrier layer. It is a biodegradable resin product.

  Embodiments of the first invention are as follows. The strip portions of each barrier layer are provided at an equal angular pitch. The center of the interval between the strip portions of the one barrier layer is formed to overlap the center of the strip portion of the other barrier layer.

According to a second aspect of the present invention, a biodegradable resin material is supplied to the entire circumference of the mandrel surface to form an inner layer portion, and a barrier layer resin material is supplied to the inner layer portion in a plurality of strips to provide an inner barrier layer. Forming an intermediate layer portion by supplying a biodegradable resin material on the inner layer portion and the inner barrier layer, and supplying a barrier layer resin material in a strip shape on the intermediate layer portion. A method for forming a biodegradable resin product is characterized in that a layer is formed and a biodegradable resin material is further supplied onto the intermediate layer portion and the outer barrier layer to form an outer layer portion.
The embodiment of the second invention is characterized in that the inner barrier layer and the intermediate layer portion are repeatedly formed a plurality of times.

According to a third aspect of the present invention, there is provided a first material flow path for supplying a biodegradable resin material to the entire circumference of the surface of the mandrel in order from the upstream in the resin material flow direction around the mandrel to form the inner layer portion, A second material flow path for supplying an inner barrier layer by supplying a barrier layer resin material to a plurality of locations on the substrate, and supplying a biodegradable resin material on the inner layer portion and the inner barrier layer A third material flow path for forming a layer portion; a fourth material flow path for supplying a barrier layer resin material in a strip shape to a plurality of locations on the intermediate layer portion to form an outer barrier layer; and the intermediate layer portion A biodegradable resin product molding apparatus is provided with a fifth material flow path for supplying a biodegradable resin material on the outer barrier layer to form an outer layer portion.
An embodiment of the third invention is characterized in that a plurality of sets of the second material channel and the third material channel are provided.

According to the biodegradable resin product and the molding apparatus thereof according to the present invention, the biodegradable resin material is included in a large proportion in the material used, and the pollution of the resin material can be effectively reduced.
According to the biodegradable resin product and the molding apparatus thereof according to the present invention, it is also possible to mold a biodegradable resin product that has a sufficient barrier property and has a strong bonding strength between the inner layer and the outer layer so that there is no practical problem. It has an effect that can be done.

An embodiment of a biodegradable resin product and a molding apparatus thereof according to the present invention will be described with reference to the drawings.
(1) Biodegradable Plastic Product FIG. 1 is a perspective view of a biodegradable resin container 10 that is one of biodegradable resin products, and is partially cut away. FIG. 2 shows a cross section of the side wall portion 12 of the biodegradable resin container 10, and shows a cylindrical portion developed in a planar shape. As shown in FIGS. 1 and 2, the biodegradable resin container 10 has a side wall portion 12, a bottom surface portion 14, and a top surface portion 16 in a plant-derived resin (non-petroleum resin) such as a biodegradable resin layer 20. Further, an inner barrier layer 22 having a barrier action and an outer barrier layer 24 having a barrier action are provided. The thickness of the side wall part 12, the bottom face part 14, and the top face part 16 is about 1.0 mm.

  The inner barrier layer 22 is located at a depth of about 0.3 mm from the inner surface of the side wall portion 12. The inner barrier layer 22 is a plurality of strip-like portions extending vertically to the bottom surface portion 14 and the top surface portion 16 in the side wall portion 12, and is made of, for example, polyethylene or polypropylene. The thickness of the inner barrier layer 22 is 0.2 to 0.03 mm. The inner barrier layer 22 of the band-shaped portion has a width of 9 °, ie, about 4.5 mm, of the biodegradable plastic container 10, and the interval between the band-shaped inner barrier layers 22 is the center angle 6 of the biodegradable resin container 10. °, ie about 3.0 mm.

  The outer barrier layer 24 is located at a depth of about 0.3 mm from the outer surface of the side wall portion 12. The outer barrier layer 24 is a plurality of belt-like portions extending vertically to the bottom surface portion 14 and the top surface portion 16 in the side wall portion 12, and is, for example, polyethylene or polypropylene. The thickness of the outer barrier layer 24 is 0.2 to 0.03 mm. The band-shaped outer barrier layer 24 has a width of 9 °, ie, about 4.5 mm, of the biodegradable resin container 10, and the interval between the band-shaped outer barrier layers 24 is 6 ° of the center angle of the biodegradable resin container 10. That is, about 3.0 mm.

  The mutual positional relationship between the inner barrier layer 22 and the outer barrier layer 24 is arranged such that the center of the interval between the strip-shaped inner barrier layer 22 coincides with the center of the width of the strip-shaped outer barrier layer 24. The number of the belt-like inner barrier layers 22 and the belt-like outer barrier layers 24 is 360 ° ÷ (9 ° + 6 °) = 24.

(2) Since the inner barrier layer 22 and the outer barrier layer 24 each have a narrow width of about 4.5 mm, the adhesive force between the biodegradable resin layer 20 and the inner barrier layer 22 and the outer barrier layer 24 is weak. However, due to the mechanical or structural coupling between the two, neither separation between the two nor separation between the inner part and the outer part of the biodegradable resin layer 20 occurs.
On the other hand, the biodegradable resin layer 20 has water permeability and air permeability. The water component and air passages in the biodegradable resin layer 20 pass through a curved path avoiding the inner barrier layer 22 and the outer barrier layer 24 as indicated by a dotted line A in FIG. The water permeability and breath resistance of the biodegradable resin layer 20 increase in proportion to the permeation distance of the biodegradable resin layer 20. Therefore, the biodegradable resin container 10 of the present invention has the same water resistance and air permeability of the biodegradable resin layer as the wall container substantially thicker than the actual thickness. In the biodegradable resin container 10 of the present invention, since the biodegradable resin layer 20 is exposed on both the inner surface and the outer surface, biodegradability is not hindered by the configuration of the present invention.

(3) Molding device The biodegradable resin product molding device of the present invention is a commonly used blow molding machine (not shown), and its resin material supply unit 100 is as shown in the sectional view of FIG. And a mandrel 110 disposed on the central axis O. The mandrel 110 has a central hole 140. Around the mandrel 110, the first flow path member 112, the second flow path member 114, the third flow path member 116, the fourth flow path member 118, the fifth path member 120, and the sixth path member are sequentially sequentially from the upper side. 122 and a seventh path member 124 are provided.

The first flow path member 112 and the second flow path member 114 are the inner layer portion 50 of the biodegradable resin layer 20 of the biodegradable resin container 10, that is, mainly the inner surface and the inner barrier layer 22 of the biodegradable resin layer 20. A first material flow path 130 for supplying a resin material filling the gap is formed.
The first flow path member 112, the second flow path member 114, and the third flow path member 116 form a second material flow path 132 that supplies a resin material that forms the inner barrier layer 22.
The second flow path member 114 and the fourth flow path member 118 are filled in the intermediate layer portion 52 of the biodegradable resin layer 20 of the biodegradable plastic container 10, that is, mainly between the inner barrier layer 22 and the outer barrier layer 24. A third material channel 134 for supplying the resin material to be formed is formed.
The fifth flow path member 120 and the sixth flow path member 122 form a fourth material flow path 136 that supplies a resin material that forms the outer barrier layer 24.
The sixth flow path member 122 and the seventh flow path member 124 are the outer layer portion 54 of the biodegradable resin layer 20 of the biodegradable resin container 10, that is, mainly the outer surface and the outer barrier layer 24 of the biodegradable resin layer 20. A fifth material flow path 138 for supplying a resin material filling the gap is formed.

The first material channel 130, the third material channel 134, and the fifth material channel 138 are formed so that the resin material goes around the entire circumference of the mandrel 110. The second material flow path 132 and the fourth material flow path 136 are configured so that 24 material flow paths exist around the mandrel 110 at an equal interval of 15 °. The 24 second material flow paths 132 and the 24 fourth material flow paths 136 are in an angular positional relationship shifted from each other by 7.5 °, that is, the center of the second material flow path 132 is the fourth material flow path 136. Is positioned so as to coincide with the center of the interval.
The third flow path member 116 is configured to divide the second material flow path 132 into 24 in combination with the second flow path member 114. The third flow path member 116 is combined with the first flow path member 112 so as to be rotatable around the central axis O, and is centered on the central axis O of the second material flow path 132 and the fourth material flow path 136. It is possible to adjust the angular position relationship.

  The blow molding blank (not shown) supplied from the molding material supply unit 100 configured as described above is determined by the molding die (not shown) by the air supplied from the center hole 140 of the mandrel 110. Finished into a shaped container. Alternatively, a blow molding blank (not shown) is inflated and cut by air supplied from the center hole 140 of the mandrel 110, and biodegraded in a predetermined shape by a molding machine (not shown) provided adjacent thereto. The resin container 10 is finished.

(4) Materials Used The biodegradable resins used in the present invention include polyhydroxybutyrate / valerate, poly-β-hydroxybutyric acid, polybutylene succinate, polybutylene succinate / adipate, polyethylene succinate, polycaprolactone , Polylactic acid, polyvinyl alcohol, starch, modified starch, cellulose acetate, chitosan / cellulose / starch and mixtures of two or more thereof. Specific examples of commercially available products include Terramac (Unitika), Novon (starch (synthetic): Novo Japan), Bionore (polybutylene succinate, polybutylene succinate / adipate: Showa Polymer), and Lacia (polylactic acid). : Mitsui Chemicals), Lactron (manufactured by Kanebo), Plaxel (manufactured by Daicel Chemical), Biomax (DuPont) and the like.

The barrier layer of the present invention can be composed of a polyolefin resin. Examples thereof include thermoplastic resins such as polyethylene, polypropylene, polyethylene-propylene, polyvinyl chloride, and polystyrene. In particular, polyethylene, polypropylene, polyethylene-propylene, and EVOH are preferable.
Although the inner layer of the plastic product of the present invention may be composed only of these polyolefin resins, it is preferably 30% by mass or less, preferably a biodegradation induction accelerator (for example, Degra Novon (registered trademark) (sold by Novon Japan)). May be contained in an amount of 20% by mass or less.

(Other embodiments)
In the embodiment described above, two barrier layers are provided, but if the number of barrier layers is three or more, the effects of the present invention can be obtained more effectively. Further, when the width of the band-shaped portions of the barrier layers 22 and 24 is increased, a more complete biodegradable resin product can be obtained by providing an adhesive resin layer between the biodegradable resin layer 20 and the barrier layers 22 and 24. I can.

FIG. 1 is a perspective view of a biodegradable resin container 10 which is one of biodegradable resin products, and is partially cut away. FIG. 2 is a cross-sectional view of the side wall portion of the biodegradable resin container. FIG. 3 is a cross-sectional view of a resin material supply section of the biodegradable resin container molding apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Biodegradable resin container 12 Side wall part 14 Bottom face part 16 Top surface part 20 Biodegradable resin layer 22 Inner barrier layer 24 Outer barrier layer 50 Inner layer part 52 Middle layer part 54 Outer layer part 100 Resin material supply part 110 Mandrel 112 1st 1 channel member 114 2nd channel member 116 3rd channel member 118 4th channel member 120 5th channel member 122 6th channel member 124 7th channel member 130 1st material channel 132 2nd material Channel 134 Third material channel 136 Fourth material channel 138 Fifth material channel 140 Center hole

Claims (6)

The entire wall portion is made of a biodegradable resin material, and includes at least two barrier layers in the wall portion, and each barrier layer has a plurality of strip portions extending in the resin material flow direction at intervals. Configured as described above, the two barrier layers are formed such that the interval between the strip portions of one of the barrier layers overlaps the strip portion of the other barrier layer,
The strip portions of each barrier layer have a width of an equal center angle centered on the vertical center line of the biodegradable resin product , and have an interval of equal center angles centered on the vertical center line of the biodegradable resin product. The biodegradable resin product according to claim 1, wherein the biodegradable resin product is provided. The entire wall portion is made of a biodegradable resin material, and includes at least two barrier layers in the wall portion, and each barrier layer has a plurality of strip portions extending in the resin material flow direction at intervals. Configured as described above, the two barrier layers are formed such that the interval between the strip portions of one of the barrier layers overlaps the strip portion of the other barrier layer,
2. The biodegradable resin product according to claim 1, wherein the center of the interval between the band-shaped portions of the one barrier layer overlaps with the center of the band-shaped portion of the other barrier layer. A biodegradable resin material is supplied to the entire circumference of the mandrel surface to form an inner layer portion, and a barrier layer resin material is supplied in a plurality of strips on the inner layer portion to form an inner barrier layer, An intermediate layer portion is formed by supplying a biodegradable resin material on the inner layer portion and the inner barrier layer, and an outer barrier layer is formed by supplying a barrier layer resin material in a strip shape on the intermediate layer portion,
The inner barrier layer and the outer barrier layer are formed such that the interval between the strip portions of one of the barrier layers overlaps the strip portion of the other barrier layer, and
A method for molding a biodegradable resin product, comprising supplying a biodegradable resin material on the intermediate layer portion and the outer barrier layer to form an outer layer portion. 4. The method for molding a biodegradable resin product according to claim 3 , wherein the inner barrier layer and the intermediate layer portion are repeatedly formed a plurality of times. A first material flow path for supplying an inner layer portion by supplying a biodegradable resin material to the entire circumference of the surface of the mandrel in order from the upstream in the resin material flow direction around the mandrel;
A second material flow path for forming an inner barrier layer by supplying a barrier layer resin material in a strip shape to a plurality of locations on the inner layer portion;
A third material flow path for supplying a biodegradable resin material on the inner layer portion and the inner barrier layer to form an intermediate layer portion;
A fourth material flow path for supplying a barrier layer resin material in a strip shape to a plurality of locations on the intermediate layer portion to form an outer barrier layer;
Providing a fifth material flow path for supplying a biodegradable resin material on the intermediate layer portion and the outer barrier layer to form an outer layer portion;
The width in the circumferential direction of the second material flow path forming the inner barrier layer and the width in the circumferential direction of the fourth material flow path forming the outer barrier layer are such that the interval between the band-shaped portions of one of the barrier layers is An apparatus for molding a biodegradable resin product, characterized in that it is determined so as to overlap with a band-shaped portion of the other barrier layer. The apparatus for molding a biodegradable resin product according to claim 5 , wherein a plurality of sets of the second material flow path and the third material flow path are provided.

Images