JP6098221B2 - Multi-layer hollow container - Google Patents

Description

  The present invention relates to a hollow container, and more particularly to a plastic hollow container containing a large amount of an inorganic filler and having excellent product properties. More specifically, it is a hollow container that contains more than half of the container weight of the inorganic filler, has excellent physical properties such as moldability and drop strength, and can be widely used in the field of containers such as shampoos, rinses, cosmetics, and foods. It relates to molded products.

Conventionally, plastic hollow molded products have been widely used in the field of containers such as shampoos, rinses, cosmetics, and foods. Resins such as polyethylene, polypropylene, and polyethylene terephthalate are widely used as plastics for hollow molded articles. Among these, polyethylene and polypropylene are preferably used from the viewpoints of performance and price.
At present, reduction of CO ₂ generated from petroleum in the natural environment is required, and reduction of petroleum-derived resin used is also required.

  For example, Patent Document 1 discloses a multilayer plastic container having a calorific value reduced to about 70% of a conventional single polyolefin container, a uniform thickness distribution, and an excellent surface property.

  Patent Document 2 discloses an easily incinerated multilayer plastic that has a sufficiently low calorie calorie compared to a conventional single polyolefin container, and that produces less off-flavors and gases during incineration, and has excellent surface properties and surface gloss. A structure is disclosed.

  Patent Document 3 discloses a resin suitable for extrusion laminating at a high molding temperature, which does not cause foaming even when the filler concentration is increased, does not generate lip stains and die lines, and is excellent in operability and can be filled with filler at a high concentration. A composition is disclosed.

  Patent Document 4 discloses a filler-containing polymer composition comprising (A) one or more α-olefin monomers and one or more vinylidene aromatic monomers and / or one or more hindered aliphatic or cyclic compounds. One or more substantially random thermoplastic interpolymers made by polymerizing aliphatic vinylidene monomers optionally with other polymerizable ethylenically unsaturated monomer (s) are (A) and ( A filler-containing polymer composition comprising 5 to 90 percent based on the total weight of B) and (B) 10 to 95 percent of one or more inorganic fillers based on the total weight of (A) and (B). Is disclosed.

However, the resin compositions of Patent Documents 1 to 4 are plastic hollow containers containing a large amount of inorganic fillers and having excellent product properties such as drop strength, and the amount of petroleum-derived resin used is sufficient. It cannot always be said that a hollow container with a reduced thickness is obtained.
In particular, when a large amount of an inorganic filler is contained, the flow of resin during molding is affected, the resin pressure during extrusion increases, the drawdown of the parison is poor, and the parison punctures during blowing. Further, there is a problem that the drop strength of the molded product container is lowered, and further physical property improvement is required.

JP 05-270534 A Japanese Patent Laid-Open No. 06-79842 JP 10-219042 A Japanese translation of PCT publication No. 2002-507229

An object of the present invention is to solve the above-mentioned problems and to provide a plastic hollow container having excellent product properties such as drop strength while containing a large amount of an inorganic filler. Hollow containers, especially shampoos, rinses, and cosmetics, with a material that accounts for more than half of the total weight of the container, the amount of petroleum-derived resin used is sufficiently suppressed, and excellent product properties such as moldability and drop strength Another object of the present invention is to provide a multilayer hollow container that can be widely used in the field of containers such as food.
In particular, it provides a hollow container that does not affect the resin flow during molding, does not increase the resin pressure during extrusion, has excellent parison draw-down resistance, and does not puncture the parison when blown. The task is to do.

As a result of intensive studies to solve the above problems, the present inventor has achieved a hollow container that solves these problems by a multilayer blow molded product formed of a laminate having a material having a specific property as an intermediate layer. As a result, the present invention has been completed.
In general, in a polymer material containing an inorganic filler, the inorganic filler causes a decrease in fracture elongation, tensile strength, and impact strength of the material. For example, when a tensile stress is applied to the material, stress concentration occurs, peeling occurs at both ends of the inorganic filler particles, and there is a tendency for craze to occur in the polymer material around the inorganic filler particles.
Accordingly, the present inventor has selected a specific laminate structure and polyethylene having a specific property as a constituent layer of the laminate in a composite material system containing a large amount of inorganic filler, thereby providing excellent impact strength and resistance. It was found that the drop impact property can be exhibited.

That is, according to the first aspect of the present invention, a multilayer hollow container containing 64.0 to 76.5 % by weight of an inorganic filler, wherein at least one layer of the container is 80 to 90% by weight of the inorganic filler. And a composition comprising 20 to 10% by weight of polyethylene satisfying the requirements specified in the following (i) to (ii), and satisfying the requirements specified in the following (I), the multilayer hollow container has at least an outer layer ( A), an intermediate layer (B), and an inner layer (C), wherein the at least one layer is the intermediate layer (B), and the multilayer hollow container has an outer layer (A) with respect to the weight of the multilayer hollow container. The weight ratio of the inner layer (C) is 7.5 to 22.2% by weight, and the outer layer (A) has an MFR of 0.03 to 5%. It is a .0g / 10 minutes, density 0.870~0.965g / cm Made of polyethylene is, the inner layer (C) is, MFR is 0.03~5.0g / 10 min, characterized in that it consists of polyethylene density is 0.870~0.965g / cm ³ A multilayer hollow container is provided.
(I) The melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg in accordance with JIS K6922-2: 1997 is 0.1 to 50 g / 10 min.
(Ii) The density measured according to JIS K6922-1 and 2: 1997 is 0.870 to 0.965 g / cm ³ .
(I) The weight ratio (Y) of the at least one layer to the weight of the multilayer hollow container is 85.0% by weight or less.

According to a second aspect of the present invention, there is provided a multilayer hollow container according to the first aspect, which is a multilayer blow-molded product.
According to a third invention of the present invention, in the first or second invention, the at least one layer has a layer weight ratio (Y) of 55.6 to 85.0% by weight, weight ratio of (Y) and the inorganic filler content of the composition (X) and is a multilayer hollow container you and satisfies the relation of the following formula (2) is provided.
Y ≧ 5600 / X Formula ( 2 )
(In the formula, the unit of X is% by weight, and the unit of Y is% by weight.)

According to the fourth invention of the present invention, in any one of the first to third inventions, the outer layer (A) polyethylene has an MFR equal to or smaller than the MFR of the polyethylene of the intermediate layer (B). A multilayer hollow container is provided.

According to a fifth aspect of the present invention, there is provided the multilayer hollow container according to any one of the first to fourth aspects, wherein the inorganic filler has an average particle size of 10 μm or less.

According to a sixth aspect of the present invention, there is provided a multilayer hollow container according to any one of the first to fifth aspects, wherein the inorganic filler is calcium carbonate or talc.

According to the present invention, a multilayer hollow container made of a plastic having excellent product properties such as moldability and drop strength while containing a large amount of an inorganic filler by a multilayer hollow molded article formed of a laminate made of a specific material. In addition, the inorganic filler accounts for more than half of the total container weight in the multi-layer container, the amount of petroleum-derived resin used is sufficiently suppressed, and the container of shampoo, rinse, cosmetics, food, etc. Multi-layer hollow containers that can be widely used in the field can be manufactured.
In particular, it provides a hollow container that does not affect the resin flow during molding, does not increase the resin pressure during extrusion, has excellent parison draw-down resistance, and does not puncture the parison when blown. can do.

With respect to a multilayer hollow container in the case where a composition comprising an inorganic filler and polyethylene having an MFR of 0.1 to 50 g / 10 min and a density of 0.870 to 0.965 g / cm ³ is used as the intermediate layer (B). The relationship between the weight ratio (Y) of an intermediate | middle layer and the inorganic filler content ratio (X) of an intermediate | middle layer is shown. The front view of an example of the multilayer hollow container of this invention, and the vertical fall direction in the drop test are shown. The side view of an example of the multilayer hollow container of this invention and the horizontal fall direction in the drop test are shown. The top view of an example of the multilayer hollow container of the present invention is shown. The bottom view of an example of the multilayer hollow container of the present invention is shown. The schematic dimension of the container used for the drop test of the multilayer hollow container of the present invention is shown.

The present invention is a multilayer hollow container containing 50 to 80% by weight of an inorganic filler, and at least one layer of the container (hereinafter also referred to as “inorganic filler-containing polyethylene resin layer”) is composed of an inorganic filler 60 to The present invention relates to a multilayer hollow container which is a composition comprising 90% by weight and specific polyethylene 40 to 10% by weight.
Hereinafter, each component and multilayer hollow container used in the present invention will be described in detail.

1. Inorganic filler The inorganic filler used in the present invention is contained in an amount of 50 to 80 wt% with respect to the multilayer hollow container, and is contained in the composition constituting the inorganic filler-containing polyethylene resin layer in an amount of 60 to 90 wt%. In the multilayer container of the present invention, the amount of petroleum-derived resin used can be sufficiently suppressed when the inorganic filler occupies more than half of the entire container weight.
(1) Kind The inorganic filler used in the present invention is an ionic inorganic compound, and specific examples of the inorganic filler are talc, calcium carbonate, alumina, glass fiber, marble powder, cement powder, clay, feldspar, silica. Or glass, fumed silica, trihydrated alumina, magnesium oxide, magnesium hydroxide, antimony oxide, zinc oxide, barium sulfate, aluminum silicate, calcium silicate, titanium dioxide, titanates, glass microspheres, chalk, Examples thereof include metal powder (aluminum, copper, iron, lead, etc.), silica, diatomaceous earth, gypsum, mica, clay, asbestos, graphite, carbon black, titanium oxide and the like. Among these inorganic fillers, barium sulfate, talc, calcium carbonate, silica / glass, glass fiber, alumina, trihydrated alumina, titanium dioxide and mixtures thereof are preferred. The most suitable inorganic filler includes calcium carbonate or talc.

The shape of the inorganic filler of the present invention is not particularly limited, but preferably has a spherical shape and an average particle size of 10 μm or less.
The average particle diameter of the inorganic filler can be measured by an air permeation method or a laser diffraction method. That is, the average particle diameter can be calculated from the measurement result of the specific surface area by the air permeation method according to JIS M-8511. For example, the powder specific surface area measuring device SS-100 type manufactured by Shimadzu Corporation (constant pressure air The average particle diameter of calcium carbonate or the like can be measured using a transmission method) or a laser diffraction particle size distribution analyzer SALD-200V manufactured by Shimadzu Corporation.

(2) Content ratio The inorganic filler of the present invention is contained in an amount of 50 to 80% by weight based on the multilayer hollow container. Preferably it is 60 to 80 weight%. If the content of the inorganic filler is less than 50% by weight, reduction of the petroleum-derived resin used cannot be achieved. On the other hand, if the content of the inorganic filler exceeds 80% by weight, is it difficult to mold the container? The physical properties of the container tend to decrease.

Moreover, the inorganic filler containing polyethylene resin layer in this invention is a composition containing 60 to 90 weight% of inorganic fillers.
If the content of the inorganic filler in the inorganic filler-containing polyethylene resin layer is less than 60% by weight, reduction of the petroleum-derived resin used cannot be achieved, whereas if it exceeds 90% by weight, it is difficult to mold the container. Or, the physical properties of the container tend to decrease.

Further, the inorganic filler-containing polyethylene resin layer has a weight ratio (Y) of the layer to the weight of the multilayer hollow container of 85.0% by weight or less, preferably 55.6 to 85.0% by weight. It is preferable that the weight ratio (Y) (wt%) and the inorganic filler content ratio (X) (wt%) in the composition have the relationship of the following formula (1), and further the following formula (2): It is preferable to satisfy.
Y ≧ 5000 / X Formula (1)
Y ≧ 5600 / X Formula (2)

  When the above formula (1) is satisfied, the ratio of the inorganic filler contained in the inorganic filler-containing polyethylene resin layer to the entire container is 50% by weight or more, and the amount of petroleum-derived resin used is sufficiently suppressed. Can do.

  The weight ratio of the inorganic filler to the weight of the multilayer hollow container is obtained by multiplying the [inorganic filler content ratio (X) / 100] by the [weight ratio of the layer (Y) / 100]. In other words, the above formulas (1) and (2) indicate that the content of the inorganic filler is preferably 50% by weight or more, more preferably 56% by weight or more, with respect to the entire multilayer hollow container. .

2. Polyethylene The inorganic filler-containing polyethylene resin layer in the present invention is a composition containing 10 to 40% by weight of polyethylene having a specific MFR and density. The multilayer hollow container laminate of the present invention preferably comprises at least an outer layer (A), an intermediate layer (B) and an inner layer (C), and the inorganic filler-containing polyethylene resin layer is an intermediate layer (B). Preferably there is. Furthermore, the outer layer (A) and the inner layer (C) are preferably made of polyethylene having a specific MFR and density.
In general, in a polymer material containing an inorganic filler, the inorganic filler causes a reduction in fracture elongation, tensile strength, and impact strength of the material, and the multilayer of the present invention containing a large amount of the inorganic filler. In the hollow container, excellent impact strength and drop impact resistance can be exhibited by selecting polyethylene having specific properties as a constituent layer of the laminate.

(1) Inorganic filler-containing polyethylene resin layer (intermediate layer (B))
The inorganic filler-containing polyethylene resin layer has an MFR of 0.1 to 50 g / 10 min, preferably 0.3 to 30 g / 10 min at a temperature of 190 ° C. and a load of 2.16 kg in accordance with JIS K6922-2: 1997. 40 to 10% by weight of polyethylene having a density measured according to JIS K6922-1 and 2: 1997 of 0.870 to 0.965 g / cm ³ , preferably 0.90 to 0.55 g / cm ³ It is a composition to contain.
When the MFR is out of the above range, the parison drawdan and parison elongation in the processing characteristics deteriorate, and the resin pressure increases. As a result, problems such as inability to form the container and a drop in the drop strength of the container remarkably occur.
Further, if the density is out of the above range, there are problems such as that the container cannot be molded and that even if the container can be molded, the drop strength of the container is significantly reduced.
Furthermore, when the content ratio of polyethylene in the inorganic filler-containing polyethylene resin layer is less than 10% by weight, it becomes difficult to mold the container, or the physical properties of the container tend to decrease, whereas when it exceeds 40% by weight, The amount of petroleum-derived resin increases, and the effect of reducing CO ₂ cannot be obtained.

(2) Outer layer (A) and inner layer (C)
The multilayer hollow container of the present invention has a laminate structure and is composed of two or more layers including at least an inorganic filler-containing polyethylene resin layer, preferably at least an outer layer (A), an intermediate layer (B), and an inner layer. The inorganic filler-containing polyethylene resin layer is the intermediate layer (B).

  The multilayer hollow container has a weight ratio (Y) of the inorganic filler-containing polyethylene resin layer of 85.0% by weight or less with respect to the weight of the entire multilayer hollow container, preferably the weight of the entire multilayer hollow container In contrast, the weight ratio of the inorganic filler-containing polyethylene resin layer (intermediate layer (B)) is 55.6 to 85.0 wt%, the weight ratio of the outer layer (A) is 7.5 to 22.2 wt%, The weight ratio of the inner layer (C) is 7.5 to 22.2% by weight. If the weight ratio of each layer constituting the laminate is out of the above range, multilayer hollow molding becomes difficult, and the properties of the molded hollow container, particularly the drop impact resistance, tend to decrease.

The outer layer (A) preferably has an MFR of 0.03 to 5.0 g / 10 min, more preferably an MFR of 0.08 to 2.0 g / 10 min, and a density of preferably 0.870 to 0.965 g. / Cm < ³ >, more preferably 0.90-0.960 g / cm < ³ >.
In the outer layer (A), when the MFR is less than 0.03 g / 10 min, problems such as an increase in motor load and resin pressure in the extruder and an increase in the heat generated by the resin occur, while the MFR is 5.0 g. If it exceeds / 10 minutes, the drawdown property of the parison is lowered and molding becomes difficult.
On the other hand, when the density of the polyethylene of the outer layer (A) is less than 0.870 g / cm ³ , defects such as poor slidability of the outer surface of the molded product occur, while the density exceeds 0.965 g / cm ³ . The rigidity becomes high and energy absorption due to deformation disappears when the product falls, and as a result, the strength of the product tends to decrease.

The outer layer (C) is preferably made of polyethylene having an MFR of 0.03 to 5.0 g / 10 min and a density of 0.870 to 0.965 g / cm ³ , and more preferably an MFR of 0.00. It is 08 to 2.0 g / 10 min, and the density is 0.90 to 0.960 g / cm ³ .
When the MFR is less than 0.03 g / 10 min, the inner layer (C) polyethylene has problems such as an increase in motor load and resin pressure in the extruder and an increase in resin heat generation, while the MFR is 5.0 g / If it exceeds 10 minutes, the draw-down property of the parison will be lowered and it will be difficult to mold.
Further, when the density of the polyethylene of the inner layer (C) is smaller than 0.870 g / cm ³ , problems such as deterioration of the slipperiness of the outer surface of the molded product occur, while the density exceeds 0.965 g / cm ³ . The rigidity becomes high and energy absorption due to deformation disappears when the product falls, and as a result, the strength of the product tends to decrease.

The polyethylene of the outer layer (A) preferably has the same or smaller MFR than the MFR of the polyethylene of the intermediate layer (B).
Basically, it is important that the resin containing the inorganic filler of the intermediate layer (B) has a characteristic that it easily stretches when melted, and the resin used for the outer layer (A) eliminates the drawdown of the parison. It is important to make it. In addition, the resin used for the outer layer (A) is a resin having a small MFR, so that air can be easily released from the mold cavity during container molding, and a product having a good appearance can be obtained. .
On the other hand, if the MFR of the polyethylene of the intermediate layer (B) is smaller than the MFR of the polyethylene of the outer layer (A), the addition of the inorganic filler increases the motor load and the resin pressure of the screw extruder, and the ability of the molding machine to be used If it is low, the resin cannot be extruded. Further, the parison does not stretch during extrusion during container molding, and when the parison is sandwiched with a mold and the parison is inflated with air from a propin, puncture is likely to occur, making it difficult to obtain a good container.

  In the present invention, the polyethylene used for the intermediate layer (B) only needs to have an MFR and density within a predetermined range, and burrs or the like generated by molding may be used as a recycled material. That is, a new intermediate layer (B) may be obtained by using polyethylene of the outer layer (A), intermediate layer (B), and inner layer (C) generated by molding as a recycled material.

(3) Kind The polyethylene used for the inorganic filler-containing polyethylene resin layer or outer layer (A), intermediate layer (B) and inner layer (C) in the present invention is ethylene homopolymerization or ethylene and carbon number 3 to 12 It can be obtained by copolymerization with an α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. Moreover, when it aims at modification | reformation, the copolymerization with diene is also possible. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene, and the like.
The comonomer content during the polymerization can be arbitrarily selected. For example, in the case of copolymerization of ethylene and an α-olefin having 3 to 12 carbon atoms, an ethylene / α-olefin copolymer is used. The α-olefin content therein is 0 to 40 mol%, preferably 0 to 30 mol%.

(4) Production method As the polymerization catalyst for polyethylene used in the present invention, various catalysts such as a Ziegler catalyst, a Phillips catalyst, and a metallocene catalyst are used. Any polymerization catalyst can be used as long as hydrogen exhibits a chain transfer action of olefin polymerization.
Specifically, any catalyst that is composed of a solid catalyst component and an organometallic compound and that is suitable for slurry-based olefin polymerization such that hydrogen exhibits a chain transfer action of olefin polymerization can be used. Preferred is a heterogeneous catalyst in which polymerization active sites are localized.
The solid catalyst component is not particularly limited as long as it is used as a solid catalyst for olefin polymerization containing a transition metal compound. As the transition metal compound, compounds of elements of Group 4 to Group 10 of the periodic table, preferably Group 4 to Group 6, can be used, and specific examples include Ti, Zr, Hf, V, Cr. And compounds such as Mo.

A metallocene catalyst is used as a preferable polyethylene polymerization catalyst used for the inorganic filler-containing polyethylene resin layer or the intermediate layer (B). A metallocene catalyst is a type of catalyst called a single-site catalyst that has a relatively single active site, and is typically a transition metal metallocene complex, such as a biscyclopentadienyl complex of zirconium or titanium. A catalyst obtained by reacting methylaluminoxane or the like as a cocatalyst can be mentioned, and it is a homogeneous or heterogeneous catalyst in which various complexes, cocatalysts, carriers and the like are variously combined.
Examples of the metallocene catalyst include JP-A-58-19309, 59-95292, 59-23011, 60-35006, 60-35007, 60-35008, and 60-35009. No. 61-130314 and JP-A-3-163088, and the like.

The polyethylene used in the present invention can be produced by a production process such as a gas phase polymerization method, a solution polymerization method, or a slurry polymerization method. Among the polymerization conditions of the ethylene polymer, the polymerization temperature can be selected from the range of 0 to 300 ° C. The polymerization pressure can be selected from the range of atmospheric pressure to about 100 kg / cm ² . It is selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, etc. in a state where oxygen and water are substantially cut off. It can be produced by polymerizing ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

In the above polymerization, hydrogen supplied to the polymerization vessel is consumed as a chain transfer agent, determines the average molecular weight of the produced ethylene-based polymer, and partly dissolves in a solvent and is discharged from the polymerization vessel. The solubility of hydrogen in the solvent is small, and the hydrogen concentration near the polymerization active point of the catalyst is low unless a large amount of gas phase is present in the polymerization vessel. Therefore, if the hydrogen supply amount is changed, the hydrogen concentration at the polymerization active point of the catalyst changes rapidly, and the molecular weight of the produced ethylene polymer changes following the hydrogen supply amount in a short time. Therefore, a more homogeneous product can be produced by changing the hydrogen supply rate in a short cycle. Moreover, the aspect of changing the hydrogen supply amount is preferably changed discontinuously rather than continuously because the effect of broadening the molecular weight distribution can be obtained.
Further, in the polyethylene according to the present invention, it is important to change the hydrogen supply amount, but other polymerization conditions such as polymerization temperature, catalyst supply amount, supply amount of olefin such as ethylene, comonomer such as 1-butene, etc. It is also important to change the supply amount of the solvent, the supply amount of the solvent, etc. as appropriate simultaneously with the change of hydrogen or separately.

  The MFR of polyethylene used in the present invention can be adjusted by the ethylene polymerization temperature, the use of a chain transfer agent, etc., and a desired product can be obtained. That is, by increasing the polymerization temperature of ethylene and α-olefin, the molecular weight can be decreased, and as a result, the MFR can be increased. By decreasing the polymerization temperature, the molecular weight can be increased, and as a result, the MFR can be decreased. . In addition, the molecular weight can be lowered by increasing the amount of hydrogen coexisting in the copolymerization reaction of ethylene and α-olefin (chain transfer agent amount), resulting in an increase in MFR, and the amount of hydrogen coexisting (chain transfer). The molecular weight can be increased by decreasing the (drug amount), and as a result, the MFR can be reduced.

  The density of the polyethylene used in the present invention can be changed by changing the type and amount of the comonomer copolymerized with ethylene, and can be reduced by increasing the amount of comonomer.

  The polyethylene produced by the above method can be pelletized by mechanical melt mixing with a pelletizer, homogenizer or the like according to a conventional method, and then molded by various molding machines to obtain a desired molded product. In addition, other than olefin polymers and rubber, etc., in addition to antioxidants (phenolic, phosphorus, sulfur), ultraviolet absorbers, Stabilizer, lubricant, antistatic agent, anti-fogging agent, anti-blocking agent, processing aid, coloring pigment, pearl pigment, glittering material, polarizing pearl pigment, crosslinking agent, foaming agent, neutralizing agent, thermal stabilizer, crystal nucleus One or more known additives such as an agent, an inorganic or organic filler, and a flame retardant can be appropriately blended. As a coloring method, a compound added in a necessary amount to the base resin or a master batch added at a high concentration may be post-blended.

  In any case, various additives may be blended with the polyethylene as necessary, and kneaded with a kneading extruder, a Banbury mixer, or the like to obtain a molding material.

3. Multilayer hollow container The multilayer hollow container of the present invention is a plastic hollow container excellent in product properties such as moldability and drop strength while containing a large amount of an inorganic filler.
In addition, the laminate of the multilayer hollow container of the present invention may include layers other than the outer layer (A), the intermediate layer (B), and the inner layer (C) without departing from the object of the present invention. For example, between the intermediate layer (B) and the inner layer (C), a gas barrier resin such as EVOH (ethylene-vinyl alcohol copolymer), a gas barrier resin and the intermediate layer (B) or the inner layer (C) It is also possible to provide an adhesive resin layer (for example, a layer made of polyolefin or the like graft-modified with an unsaturated compound such as maleic anhydride). Further, a resin having little influence on the inner solution can be provided in the innermost layer, or the innermost surface can be processed such as coating. Furthermore, from the viewpoint of reducing the manufacturing cost of the molded product, a recycled layer using a recycled resin material obtained by pulverizing burrs generated during molding may be provided.

(1) Manufacturing Method The multilayer hollow container of the present invention (hereinafter also referred to as “multilayer blow molded product”) can be obtained by multilayer molding with an ordinary multilayer blow molding machine. The molding conditions can be appropriately set depending on the size and shape of the molded product to be obtained.
Specifically, it is possible to use a blow molding machine having a head structure which is composed of three or more types of extruders and can form three or more types of layer structures. Furthermore, in addition to the structure having three layers of the outer layer (A), the intermediate layer (B) and the inner layer (C), a four-layer equipped with an extruder for a recycled resin layer using burrs generated during molding It may be a blow molding machine having a structured head. Further, when making a container with a gas barrier layer added, a multilayer blow molding machine in which an extruder is added or the layer structure of the head is changed may be used. The mold clamping device can be used with a device provided in a normal blow molding machine.
In addition, the multilayer hollow container of the present invention may be decorated with a screen, etc., an in-mold label in which a label is inserted into a mold during multilayer blow molding, or a shrink film or a stretch film. .
The weight ratio of the layers of the multilayer hollow container can be obtained by measuring the extrusion amount of each layer for each extruder under the molding and extrusion conditions of each container.

  As the cooling mold used for the production of the multilayer blow molded article of the present invention, a mold during normal blow molding can be used. The cavity surface of the mold is sandblasted, and is applied to remove the air existing between the mold cavity and the parison when the parison is sandwiched between the mold cavity surface and the parison is inflated with an air pin. There are many.

(2) Molded Product The multilayer blow molded product of the present invention can be made into a blow molded product by a blow molding method, particularly a multilayer blow molded product with a multilayer blow molding machine. The size of the multilayer blow molded product is not particularly limited, but is preferably about 10 to 2000 ml. Further, the shape of the container is not particularly limited. One embodiment of the multilayer blow molded article of the present invention is shown in FIGS.
The multi-layer blow molded article of the present invention can provide a variety of containers ranging from rigid to flexible. Usually, when containing an inorganic substance, there is a decrease in strength at the time of dropping, etc., but the multilayer blow molded product of the present invention is excellent in physical properties such as a drop impact strength and can reduce the burning calories at the time of incineration, shampoo, rinse It can be suitably used as a container for cosmetics, a food container, etc., and has very high industrial utility.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist. The measurement and evaluation methods used in the examples are as follows.

1. Measurement / Evaluation Method (1) Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg: Measured according to JIS K6922-2: 1997. The melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg was measured according to JIS K6922-2: 1997.
(2) Density: Measured according to JIS K6922-1 and 2: 1997.
(3) Weight ratio of layer: The extrusion rate of each layer for each extruder was measured under the molding and extrusion conditions of each container, and the weight ratio of each layer was determined.
(4) Drawdown resistance:
The value obtained by dividing the time required for the length of the parison extruded from the die of the extruder to reach 60 cm by the time required to reach 12 cm is 3.0 or more when the drawdown resistance is “◯”, and less than 3.0 is the drawdown resistance. The sex was “x”.
(5) Puncture resistance during container molding:
In the formation of the multi-layer container, a case where the parison was not punctured was indicated by “◯”, and a case where the parison was punctured was denoted by “X”.
(6) Pinch-off moldability:
The peeling of the molded parison fusion part (pinch-off) at the bottom of the container was visually determined, and “o” indicates that there is no peeling, and “x” indicates that there is peeling.
(7) Evaluation of formation results:
A parison that was shaped without being punctured with a mold was defined as “good”, and a punctured hole with a hole was defined as “bad”.
(8) Drop strength and number of breaks:
Water for 90% of the full water volume of the container was put in, sealed, and a drop test was conducted at a normal temperature from a height of 1.2 m, and the number of breaks reached in the drop test was measured. The result of dropping the container in both the vertical direction and the horizontal direction of the container is defined as one time, and it is repeatedly dropped at least five times. .

2. Resin material used (1) Polyethylene resin As the polyethylene resin, in the outer layer (A) and the inner layer (C), polyethylene (H-1), (H-3), (H- 4), (H-6) and (H-7), and the intermediate layer (B), the following polyethylene (M-1), (M-3), (M-4) having the predetermined physical properties shown in Table 1 ), (M-8) and (M-9) were used.

(2) Inorganic filler As inorganic filler, calcium carbonate (manufactured by Takehara Chemical Industry Co., Ltd., average particle size: 4 to 5 microns, shape: particle shape) and talc (manufactured by Takehara Chemical Industry Co., Ltd., average particle size: 3) .5 micron shape: plate shape) was used.

2. Molding and evaluation of multilayer hollow container [Examples 1 , 4, 8, 10 and 11, Reference Examples 2, 3, 5, 6 , 7, 9 and 12 and Comparative Examples 1 to 12]
In the composition ratios shown in Tables 2 to 4, polyethylene and inorganic filler were blended in a mixer, and then melt-kneaded using a biaxial extruder to obtain a composition constituting the intermediate layer (B). .
In a three-layer head structure, the outer layer (A) resin screw diameter was 30 mmφ, the intermediate layer (B) resin screw diameter was 40 mmφ, and the inner layer (C) resin screw diameter was 30 mmφ. A 500 ml flat container is prepared by extruding a parison in which the screw rotation speed is adjusted under the temperature setting and the layer ratio of the outer layer (A), the intermediate layer (B) and the inner layer (C) is set to a predetermined ratio shown in Tables 2-4. Blow molding was performed at a blow mold for use, a mold temperature of 20 ° C., a blow pressure of 6 kg / cm ² , a bottle weight of 22 g, and a molding cycle of 12 seconds. Multilayer blow molding was performed at a parison temperature of 225 ° C. to form a multilayer hollow container shown in FIG.

  Each of the obtained multilayer hollow containers was evaluated for performance by the method described in the measurement / evaluation method. The obtained results are shown in Tables 2-4.

As is apparent from the evaluation results of Tables 2 to 4, the multilayer hollow container of the example of the present invention employs polyethylene having specific physical properties for the inorganic filler-containing polyethylene resin layer / intermediate layer (B), and has a specific multilayer structure. By adopting, there is no drawdown property when the parison is extruded in multilayer blow molding and there is no puncture of the container at the time of blowing, and good workability is obtained without adversely affecting the container molding. In addition, it can be seen that a product satisfying the practical properties when commercialized is obtained in terms of the drop strength physical properties of the molded multilayer molded container product.
On the other hand, it can be seen that the containers of Comparative Examples 2, 4, and 6 to 12 have poor results in drawdown property, container puncture phenomenon, and / or product drop strength physical properties.
Further, in Comparative Examples 1, 3, and 5, the content of the inorganic filler in the multilayer hollow container is 50% by weight or less, so that the amount of CO ₂ generated at the time of incineration is large and the reduction of petroleum-derived resin cannot be achieved.

According to the present invention, a plastic blow-molded product having excellent product properties while containing a large amount of an inorganic substance, wherein the inorganic substance contains more than half of the entire container weight in a multi-layer container, and CO ₂ generation from petroleum is generated. Multi-layer blow-molded products that can greatly reduce the amount and have excellent product drop strength performance in terms of product performance and can be widely used in the field of containers such as shampoos, rinses, cosmetics, foods, etc. Can be provided.

DESCRIPTION OF SYMBOLS 1 Multilayer hollow container 2 Trunk part 3 Shoulder part 4 Lid attachment part 5 Mouth part

Claims (6)

A multilayer hollow container containing 64.0 to 76.5 % by weight of an inorganic filler, wherein at least one layer of the container includes 80 to 90% by weight of the inorganic filler and the following requirements (i) to (ii) The composition is composed of 20 to 10% by weight of polyethylene, and satisfies the requirements specified in (I) below. The multilayer hollow container has at least an outer layer (A), an intermediate layer (B), and an inner layer (C). The at least one layer is an intermediate layer (B), and the multilayer hollow container has a weight ratio of the outer layer (A) of 7.5 to 22.2% by weight with respect to the weight of the multilayer hollow container. The weight ratio of the inner layer (C) is 7.5 to 22.2% by weight, the outer layer (A) has an MFR of 0.03 to 5.0 g / 10 min, and a density of 0.870. made of polyethylene is ~0.965g / cm ^3, the inner layer C) is, MFR is 0.03~5.0g / 10 min, a multilayer hollow container, characterized in that it consists of polyethylene density is 0.870~0.965g / cm ^3.
(I) The melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg in accordance with JIS K6922-2: 1997 is 0.1 to 50 g / 10 min.
(Ii) The density measured according to JIS K6922-1 and 2: 1997 is 0.870 to 0.965 g / cm ³ .
(I) The weight ratio (Y) of the at least one layer to the weight of the multilayer hollow container is 85.0% by weight or less.   The multilayer hollow container according to claim 1, which is a multilayer blow molded article. The at least one layer has a layer weight ratio (Y) of 55.6 to 85.0 wt%, and a layer weight ratio (Y) and an inorganic filler content ratio (X) in the composition, Satisfies the relationship of the following formula (2), the multilayer hollow container according to claim 1 or 2.
Y ≧ 5600 / X Formula (2)
(In the formula, the unit of X is% by weight, and the unit of Y is% by weight.)   The multilayer hollow container according to any one of claims 1 to 3, wherein the polyethylene of the outer layer (A) has an MFR equal to or smaller than that of the polyethylene of the intermediate layer (B).   The multilayer filler according to any one of claims 1 to 4, wherein the inorganic filler has an average particle size of 10 µm or less.   The multilayer hollow container according to any one of claims 1 to 5, wherein the inorganic filler is calcium carbonate or talc.