JP2017019422A - Multi-layer molding block for ship and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layer molding block for a ship which has a small load deformation amount with respect to a large ship and hardly causes a crack, and a production method thereof.SOLUTION: There are provided multi-layer molding blocks 1, 2 formed of a core layer 3 and a shell layer 4 for covering a surface of the core layer. The core layer 3 is formed of a resin expanded material having high or intermediate expansion ratio. The shell layer 4 is formed of a resin non-expansion material or a low-expansion material. The blocks have compression strength of equal to or more than 0.9 kN/cm2, and satisfy conditions that, a crack does not occur at a load of 2000 kN, compression strain at 1000 kN load breakage is 120 mm or lower, and a total area ratio occupied by the high or intermediate expanded material on a vertical cross section is 15-60%.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a resin board for installing on a ship's bottom and supporting the ship's bottom, and more specifically, a multi-layer molding machine for a ship which is small in load deformation and hardly cracks even on a large ship. The present invention relates to a tree and a manufacturing method thereof.

  Conventionally, a ship board is an indispensable member for supporting a ship by installing it on the bottom of a ship that was entered during shipbuilding or ship repair, and usually a wooden board is stacked on a concrete bed. And the like, and those obtained by stacking a resin board and a wooden board on a concrete base board. The resin board is first put to practical use by the applicant, CM Material Co., Ltd., and is used mainly by major shipbuilding companies. Moreover, in the case of a wooden board, it is common to use a combination of a hard wooden board such as firewood and a soft wooden board such as pine. In other words, the board is required to have a good balance between the soft pine cushioning and the rigidity of the heel.

  In recent years, energy-saving boats have been subjected to excessive loads on the wood planks that support the bottom of the boat as a result of the adoption of slimmer and edged (sharpened) designs to reduce the flow resistance at the bottom. Some of the resin board blocks cause material destruction. Imported timber from overseas, which is used as a material for wooden board, has been banned from export of raw wood to protect resources, and the price of sawn timber products has risen significantly, making it difficult to obtain every year. On the other hand, the current resin board has a large strain deformation amount, although it is difficult to destroy the material even for an energy saving ship with a load of 50 to 100 tons. Therefore, there is a strong demand for the development of high-performance marine resin board that can withstand a load of 200 tons.

  Further, Patent Document 1 discloses an automatic rock board device characterized in that a support body that comes into contact with the ship's hull is composed of an elastic body that has a hardness that can support the hull and has a sufficient thickness that can be deformed. Has been. And the structure which formed the hollow part in the support body and press-fit fluids, such as gas, a liquid, a granular material, is described in it. Further, a composite structure is described in which the support is made of an elastic body such as rubber or synthetic resin, and a restraining material such as a woven fabric or a non-woven fabric is laminated and embedded in the elastic body.

JP 2002-249098 A

  However, the role of the support in the automatic board device described in the above-mentioned Patent Document 1 is that when a load is applied to the support, the support itself is deformed and the followability of the support surface with respect to the shape of the ship's hull increases, and It is to ensure close contact support. In contrast, the inventor of the present invention has a multilayer / foam structure as an internal structure model of a resin board, and the core layer and the shell layer are formed of foams having different foam ratios, and the core layer has a high foam ratio. Knowing that by increasing the rigidity and making the shell layer non-foamed to low foaming ratio and adding an elastomer component, the balance of cushioning and rigidity that the board should originally have is maintained and cracks are prevented. The present invention has been conceived, and the main object of the present invention is to provide a high-performance multilayer molded board for marine vessels that can withstand high loads by reducing the amount of strain deformation under high loads. .

In order to solve the above-mentioned problems, the present invention provides a marine multilayer molded board comprising a core layer and a shell layer covering the surface of the core layer.
The core layer is composed of large foam or medium foam resin foam, and the shell layer is composed of resin non-foam or low foam,
The compressive strength is 0.9 / cm 2 or more, no crack is generated at a load of 2000 kN, the compressive strain at a load failure of 1000 kN is 120 mm or less, and the total area ratio occupied by the large and medium foamed portions in the longitudinal section is It is set as the multilayer molded board for ships characterized by being 15 to 60%.

  In order to solve the above-mentioned problems, the present invention provides that the core layer or the shell layer constituting the marine multilayer molded board has at least 20 to 60 parts by mass of an ethylene / vinyl acetate copolymer, high-density polyethylene. 10 to 80 parts by mass, 15 to 35 parts by mass of polypropylene and 3 to 50 parts by mass of a thermoplastic elastomer are contained within the range of parts by mass. It is preferable to use the above-mentioned multilayer molded board for marine vessels.

  In order to solve the above problems, the present invention provides a one-step molding process in which a foamable molten resin is injected into a mold to form a two-layer formed of a core layer and a shell layer, and the one-step molding method. Placing the molded preform in the cavity of the insert molding die, and foaming for forming a core layer and a shell layer by clamping the die on which the molding preform is placed A two-stage molding process in which molten resin is injected into a mold in which the preform molded body is disposed to mold an insert molded body, and a multi-stage / multi-layer foam molded body is obtained by repeating the two-stage molding process. It is set as the manufacturing method of the multilayer molded board for a ship.

  As described above, a multilayer molded board for a ship according to the present invention has a multilayer / foam structure as an internal structure model of a resin board, and the core layer and the shell layer are formed of foams having different expansion ratios, respectively. The foaming ratio is increased and hardened to reduce the deformation amount, the shell layer is made non-foamed to low foaming ratio, and the elastomer component is added to strengthen and prevent the occurrence of cracks. Furthermore, a preform molded body for insert molding that constitutes a core layer made of a foam is formed by an insert molding method, etc., and this preform molded body is placed in a cavity to form a shell layer, which is sequentially repeated in multiple layers. By molding, a shell layer of non-foaming or low foaming ratio is formed.

(A) is explanatory drawing of the flat board which consists of a two-stage molded object which concerns on an Example, F represents the direction of the force applied in the case of the test. (B) is explanatory drawing of the sheet pile wood which consists of a two-stage molded object which concerns on an Example.

It is a graph showing the correlation between compressive strength and the ratio of large and medium foamed parts (%).

  Modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail below. However, the present invention is not limited to such an embodiment.

  A marine multilayer molded board according to claim 1 of the present application is a marine multilayer molded board composed of a core layer and a shell layer covering the surface of the core layer. The shell layer is composed of a non-foamed portion or a low-foamed portion made of resin, and the core layer and the shell layer are each composed of one or more layers. Further, the marine multilayer molded board composed of the core layer and the shell layer covering the surface thereof has a compressive strength of 0.9 kN / cm2 or more, and no cracks are generated at a load of 2000 kN. The compressive strain is 120 mm or less, and the total area ratio of the large and medium foamed portions in the longitudinal section is 15 to 60%. The total area ratio occupied by the large and medium foamed portions is the total cross-sectional area of the large foamed portion and the middle foamed portion in the core layer of the first-stage molded portion or the second-stage molded portion in the resin foam of 1 to multi-stage molding. The ratio to the cross-sectional area. Here, the size of the foam cell in the longitudinal section is 1 mm or more for the large foam part, 0.5 mm or more and less than 1 mm for the medium foam part, and the low foam part (small foam part to fine foam part) is less than 0.5 mm. Refers to the foaming site. In terms of the expansion ratio ER, the large foamed part corresponds to a foaming part of 5 or more, the middle foaming part of 2 or more and less than 5, and the low foaming part (small foaming part to fine foaming part) corresponds to a foaming part of less than 2. The expansion ratio ER (expansion ratio) is represented by ER = ρ / ρf, where ρ is the solid density and ρf is the apparent density of the foam.

  In the said material, as a resin used for a core layer thru | or a shell layer, either a thermoplastic resin or a thermosetting resin may be sufficient. Examples of such thermoplastic resins include high density polyethylene (HDPE), low density polyethylene, linear low density polyethylene, polypropylene (PP), ethylene / vinyl acetate copolymer (EVA), vinyl chloride resin, vinyl chloride / Vinyl acetate copolymer, polystyrene, syndiotactic polystyrene, acrylic resin, ABS resin, aliphatic polyamide resin, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyetheretherketone Polyphenylene sulfide, cellulosic plastic, etc., or copolymers or blends thereof can be used.

  On the other hand, as thermosetting resin, polyurethane resin, phenol resin, unsaturated polyester, diallyl phthalate resin, vinyl ester resin, epoxy resin, urea resin, melamine resin, polyimide resin, polyamideimide resin, acrylic resin, natural rubber, synthetic Rubber etc. can be used. Further, it may be a resin in the form of liquid, powder, granules or pellets before the reaction and foams. Two or more of these may be used in combination. Furthermore, the thermosetting resin and the thermoplastic resin can be used in combination.

  As the elastomer, a thermoplastic elastomer (TPE) is preferable, and a polymer chain (A) having a high glass transition temperature and a low chain (B) (A as polystyrene, B as poly (ethylene / propylene) (PE / P), poly ( Elastomer / butylene (PE / B), polybutadiene (PB) or polyisoprene (PI), etc.) are connected to each other in the form of ABA. preferable. TPE based on styrene block copolymer is generally called TPS, and TPS is classified into SEBS, SBS, SEPS, and SEPS-V, and styrene end blocks are combined with elastic blocks such as ethylene butylene.

  These styrene TPS are used as injection molding materials. In the present embodiment, not only the thermoplastic elastomer (TPE) exhibits toughness as an elastomer, but also an ethylene / vinyl acetate copolymer (EVA), high-density polyethylene (HDPE), and polypropylene (PP). It is considered that it acts as a compatibilizing agent for blending and improves mechanical properties such as breaking strength. Further, in addition to the resin and elastomer, fillers, foaming agents, stabilizers, ultraviolet absorbers, antistatic agents, flame retardants, colorants, viscosity modifiers, processing aids, reinforcing materials, and the like may be added.

  Next, basic blending of materials used for the marine multilayer molded board in the present embodiment will be described. Although the manufacturing method of the multilayer molded board for ships in this Embodiment is not specifically limited, Injection molding, extrusion molding, cast molding, etc. are preferable. Although it will not specifically limit if it is a material suitable for the shaping | molding as a material to be used, It is preferable to contain the material which concerns on any combination in polyolefin resin, an ethylene-type copolymer, and an elastomer. As the polyolefin resin, any one or a combination of high density polyethylene (HDPE), low density polyethylene, linear low density polyethylene, and polypropylene (PP) may be used. The ethylene copolymer is preferably an ethylene / vinyl acetate copolymer (EVA), and the elastomer is preferably a thermoplastic elastomer (TPE).

  As a compounding ratio of the material constituting the core layer, for example, ethylene / vinyl acetate copolymer (EVA) is 40 to 60 parts by mass, high density polyethylene (HDPE) is 10 to 30 parts by mass, and polypropylene (PP). 15 to 35 parts by mass and 3 to 50 parts by mass of the thermoplastic elastomer (TPE) are preferable. Furthermore, it is preferable to add 2 to 10 parts by mass of a foaming agent according to the expansion ratio. The foaming agent may be either an organic or inorganic chemical foaming agent or a physical foaming agent such as a capsule. Although it does not specifically limit as a foaming agent, An azo type foaming agent is preferable. In the case of urethane foam, a diol and diisocyanate are reacted by cast molding to form a prepolymer, and carbon dioxide is generated when forming a network structure with water as a crosslinking agent. Plays the role of a foaming agent to form a foam. As long as the material sufficiently satisfies the quality as well as a new material (virgin raw material), it is also possible to use a so-called off-grade product such as a regenerated product containing a foaming agent or a B-grade product.

  The blending ratio of the material constituting the shell layer is preferably the same as the blending ratio of the material constituting the core layer or includes at least one common material among the materials constituting the core layer. Furthermore, it is preferable that the foaming agent is not included or the amount of foaming agent added is smaller than the amount of core layer added. However, since the size of the foamed cell and the foaming ratio vary depending on the molding method and molding conditions (temperature to time), it is preferable to appropriately adjust the amount of the foaming agent added according to the molding method and molding conditions.

  Next, as a method of forming the core layer and the shell layer using the above materials, a one-step molding method using a one-shot method is possible, and a two-layer molding obtained by the one-step molding method is insert-molded. A core layer and a shell layer are newly formed by two-stage molding in which a molten resin is injected outside the preform molded body, which is disposed as a preform molded body for use in a cavity of an insert molding mold. It is possible to form a multi-layered molded body by repeating such insert molding method by multi-stage molding. According to the injection molding method, a portion close to the mold is first cooled to form a non-foamed or low-foamed shell layer, and then a high-temperature portion is foamed to form a core layer composed of large and medium foamed portions. Is done. In this way, the core layer consisting of large and medium foamed parts and the non-foamed or low-foamed shell layer overlap each other, or by forming a multi-layered molded body, it is more tough and capable of withstanding high loads of 200 tons. A resin board is obtained.

  Moreover, although it does not limit as a shaping | molding method, it can shape | mold by cast molding, extrusion molding, etc. other than the said injection molding. Injection molding is a short shot method that fills the foamable molten resin in an amount smaller than the mold cavity volume and completes the filling by expanding the bubbles, and fills the foamable molten resin in an amount equal to the mold cavity volume. When filling with foamable molten resin using a full shot method that compensates for solidification shrinkage by the generation and expansion of bubbles, or a mold with variable cavity volume, the cavity volume is narrowed and the cavity is filled during or after filling. It is possible to apply a core back method that gradually expands the tea volume and generates bubbles. For the multilayer molded board for marine use according to the present invention, a molding method that applies the core back method for enhancing the cushioning property or rigidity of the foam molded product is preferable.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

  As examples of blending used in the present Examples to Comparative Examples, the blends used in the two-stage molding of Example 1, Example 2, Example 3, and Comparative Example 1, Comparative Example 2, Comparative Example 3, and Example 5 in advance are used. Preparation of preparation was carried out, and these experiments were combined as appropriate to carry out experiments of Examples 1 to 3, Examples 5 to 8, and Comparative Examples 1 to 3. In this formulation, an ethylene / vinyl acetate copolymer (EVA), high-density polyethylene (HDPE), polypropylene (PP), styrene-based thermoplastic elastomer (TPE), and a material containing an azo-based blowing agent depending on the expansion ratio are used. A blended material was prepared by stirring and mixing with a blender. A molded body was molded from each of the above blended materials using a predetermined injection molding machine. The EVA is a foam / hollow molding grade product with a VA content of 19%, the HDPE is a hollow molding grade product with an MFR of 0.36 g / 10 min and a density of 0.956 g / cm3, and the PP is an MFR of 11 g / 10 min with a density. 0.90 g / cm3 of general injection grade products, TPE includes olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers or styrene-butadiene-based thermoplastic elastomers, and foamed regenerated products and some or all of them. The replaced compound was used.

  Next, the molding method is performed by injection molding. In insert molding, a preform molded body for insert molding is placed in the cavity of the mold for insert molding, and a foamable molten resin for forming a two-stage molded part is used. An insert molded body was formed by injection. In the case of three-stage molding, the preform formed by the above-mentioned two-stage molding is placed in the cavity of the mold for insert molding, and the insert molded body is molded by injecting foamable molten resin for forming the three-stage molded part. did. The molding conditions in injection molding are as shown in Table 4 below. A bending test and a compression test were performed to measure bending strength, compressive strain, hardness, and the like. The test results are shown in Tables 1 to 3. Table 1 shows Examples 1 to 3, Table 2 shows Examples 5 to 8, and Table 3 shows Comparative Examples 1 to 3, respectively.

In addition, the testing machine, test piece, and test conditions used for the compression test and the bending test of the present example are as follows.
Test machine: A 10MN structure compression bending test machine (use range: 2000 kN) was used.
Test piece: An injection-molded body of 400 L × 300 W × 200 Tmm was used.
Compression surface: Pressurized in a direction perpendicular to the surface of 400 L × 300 W (F in FIG. 1A).
Test speed: 2 mm / min (bending test), 5 mm / min (compression test)
In the bending test, the specimen is pressed by the loading steel plate attached to the upper bed, and the loading steel plate attached to the lower bed is a stack of two steel plates as a lower jig, with an interval of 250 mm across the center of the specimen. Was opened and installed. The core size and board size of the two-layer molded body according to this example are shown below (Table 5).

From Table 5, the total volume of flat wood is Val, the core volume is Vco, the shell volume is Vsh,
When the volume occupied by the shell layer relative to the total volume is Vsp,
Val = (W1) × (H1) × (L1), Vco = (W2) × (H2) × (L2), Vsh = Val−Vco, Vsp = 100 × Vsh / Val.
Similarly, the total volume of the sheet wood is Val = (W3) × ((h3) + (H3)) × (L3) / 2,
The core volume is Vco = (W4) × (H4) × (L4), Vsh = Val−Vco,
Vsp = 100 × Vsh / Val.

  From Table 1, Table 2 and Table 3, the compressive strength is preferably 0.9 kN / cm 2 or more. If it is less than 0.9 kN / cm 2, the strength may be insufficient and it may be difficult to support a large vessel. Further, the compressive strain at breakage under a load of 1000 kN is preferably 120 mm or less. If the compressive strain exceeds 120 mm, it may be difficult to reliably support the ship. Furthermore, it is preferable that cracks do not occur at a load of 2000 kN. If a crack occurs at a load of 2000 kN, the strength is insufficient and it may be difficult to support a large ship.

  In addition, FIG. 2 shows two variables, that is, the total foam area ratio, for a total of 10 cases of Examples 1 to 3 (Table 1), Examples 5 to 8 (Table 2), and Comparative Examples 1 to 3 (Table 3). (%) And compressive strength (kN / cm2) are respectively plotted on a graph with the horizontal axis (large / middle foam part ratio) and vertical axis (compressive strength), respectively, and a graph showing the presence or absence of a correlation with a straight line. is there. As can be seen from this graph, there is a correlation between the compressive strength and the ratio of the large and medium foamed parts. In Comparative Examples 1 to 3, when the ratio of the large and medium foamed parts exceeds 60%, the compressive strength becomes a limit value of 0.9 kN / It becomes lower than cm 2 and causes cracking. On the other hand, when the ratio of the large and medium foamed parts is around 20% as in Examples 7 and 8, the compressive strength is also increased to 3 kN / cm 2. Therefore, in order to suppress the generation of cracks and increase the compressive strength, it is preferable to suppress the ratio of the large and medium foamed portions to 60% or less. Moreover, regarding the compressive strain at the time of 1000 kN load failure, Comparative Example 1 is larger than 120 mm, while Comparative Examples 2 and 3 are within 120 mm, but do not satisfy the compressive strength.

  The multi-layer molded board for ships according to the present invention provides a high-performance multi-layer molded board for ships that can withstand high loads by reducing the amount of strain deformation under high loads, and is useful for the natural protection of forests and trees, etc. Also useful.

1 board (flat board)
2 Woodcut (Yabaki)
3 Core layer 4 Shell layer

Claims (3)

In a marine multilayer molded board composed of a core layer and a shell layer covering the surface,
The core layer is composed of large foam or medium foam resin foam, and the shell layer is composed of resin non-foam or low foam,
The compressive strength is 0.9 / cm 2 or more, no crack is generated at a load of 2000 kN, the compressive strain at a load failure of 1000 kN is 120 mm or less, and the total area ratio occupied by the large and medium foamed portions in the longitudinal section is A multilayer molded board for ships, characterized by being 15 to 60%.   The core layer or shell layer constituting the marine multilayer molded board is at least 20 to 60 parts by mass of ethylene / vinyl acetate copolymer, 10 to 80 parts by mass of high density polyethylene, 15 to 35 parts by mass of polypropylene, and The marine multilayer molded board according to claim 1, wherein the thermoplastic elastomer contains any compounding material selected from 3 to 50 parts by mass within the range of the parts by mass.   A one-stage molding process in which a foamable molten resin is injected into a mold to form a two-layered structure including a core layer and a shell layer, and a preform formed by the one-stage molding method is used as a cavity of an insert molding mold. A step of arranging, and a mold on which the preform for molding is arranged is clamped, and a foamable molten resin for forming a core layer and a shell layer is attached to the mold on which the preform is arranged A method for manufacturing a marine multilayer molded board, comprising: a two-stage molding step of injection molding to form an insert molded body, and a multi-stage / multi-layer foam molded body obtained by repeating the two-stage molding step.

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