JP2023032969A - Transportation containers, partitioning members or packing cushioning materials for transportation containers made of polypropylene resin foam having sustained antistatic performance also on foam surface and in internal foam layer of foam, and uses of transportation containers, partitioning members, and packing cushioning materials for transportation containers in antibacterial and antifungal applications - Google Patents

Abstract

To provide a polypropylene resin foam product having excellent antistatic properties.MEANS: Provided are transportation containers, partitioning members and packing cushioning materials for transportation containers with sustained antistatic performance consisting of polypropylene resin foam that uses a polypropylene resin as a base resin and contains a BN type charge-transfer type antistatic agent in a range of 0.1 to 2.0 parts by mass in the base resin, wherein surface resistivity of a surface of the polypropylene resin foam, and that of a foam resin layer of a slice surface measured in accordance with JISK6911 are each 1.00×1013 Ω/sq or less.SELECTED DRAWING: None

Description

The present invention provides a transportation container, a partition member for a transportation container, and a cushioning material for packing, using a polypropylene resin foam having a continuous antistatic performance that is excellent in antistatic performance on the surface of the foam and the foam layer inside the foam. The present invention relates to a material, a method for manufacturing the same, and the use of these transportation containers, partition members of transportation containers, and cushioning materials for packaging for antibacterial and antifungal purposes.

Plastics are characterized by high electrical insulation and are used in a wide range of fields. However, due to this property, it is easily electrified and easily generates static electricity. This results in unwanted troubles related to static electricity. The most typical example is the adhesion of dirt and dust to plastic products. In addition, when static electricity is the most serious problem, discharge may cause malfunction or destruction of ICs, memory chips, and the like in electronic equipment and OA equipment.

In order to prevent such a phenomenon, countermeasures are taken to prevent static electricity. It is believed that the accumulation of static electricity can be suppressed by setting the resistance to ^13Ω or less.

Methods for preventing static electricity include a method of surface-treating plastics and a method of kneading plastics with a substance that imparts electrical conductivity. For example, it is possible to apply or knead a surfactant on the surface of a plastic, and it is possible to obtain an effect even with a small amount of use. Moreover, in the case of a hydrophilic surfactant, the effect is exhibited by the surfactant absorbing moisture.

However, this method has a problem that the effect does not last if the antistatic agent on the surface is lost. Moreover, even when the surfactant is kneaded into the resin, there is a problem that the surface of the resin is contaminated by bleeding out of the surfactant, and the product to be packed is contaminated. Moreover, since the surfactant has low heat resistance, it may decompose during molding.

Conductive fillers such as carbon black and carbon fiber can be considered as additives that do not have such problems, but they require a large amount of compounding, blacken the molded product and limit its application, and impact resistance is poor. There is a problem of lowering In the case of this method, the surface specific resistance can be significantly reduced, but problems such as cost and coloring of the product remain.

On the other hand, polymeric antistatic agents that do not bleed out, that is, long-lasting antistatic agents have been studied. For example, polyethylene glycol-methacrylate copolymers, polyether ester amides, polyether ester imides, which generally have a structure in which conductive units such as polyethylene oxide (PEO) are incorporated into the polymer chain in blocks or at random, Polyethylene oxide hydrin copolymers and the like have been put to practical use.

In the case of such a polymer-type antistatic agent, there are problems such as the need to add a large amount and difficulty in controlling dispersion in the resin due to the difference in viscosity from the base resin. In order to reduce costs, laminated resin foams have been developed in which an antistatic film layer is laminated on the surface of a resin foam by co-extrusion for use as a cushioning material for packaging or a partition material.

On the other hand, inorganic boron compounds are used in industrial fields such as medicine, glass, ceramics, metal welding, semiconductors, etc., but methyl ester, ethyl ester and amyl ester of boric acid are the first organic boron compounds. However, boron compounds with a BO bond have been made since then.

Boron is usually trivalent and forms a compound bonded on a plane, but since it has one more empty orbital, it has the property of forming a tetravalent and tetrahedral structure compound when there is an adjacent hydroxyl group. The compound is characterized by a characteristic semi-polar bond between boron (B) and adjacent hydroxyl groups (OH).

On the other hand, the BN complex, which is structurally designed to be compatible with non-polar resins, has a polar part (BN) while the main chain part is held as an anchor in the target resin matrix. Can be fixed to the surface. As an antistatic agent using such a BN complex, there is BN105 as a BN type charge transfer type antistatic agent.

On the other hand, polypropylene resin foam is used as a cushioning material for packaging, and it is particularly used as a packaging material for transporting electronic equipment parts. In addition to performance, mold and fungi cause deterioration of the insulating substrate, noise generation, short circuit, etc. due to the decrease in pitch of the wiring pattern on the wiring board and the increase in use under harsh conditions with high humidity. In order to prevent the generation of , antibacterial properties and antifungal properties have been required for substrate materials of wiring boards and electronic parts.

Along with this, not only substrate materials for wiring boards and electronic parts, but also transport packaging materials that come into contact with these parts are required to have not only antistatic performance but also antibacterial and antifungal properties.

Antibacterial agents are roughly classified into organic antibacterial agents and antifungal agents into organic antibacterial agents and inorganic antibacterial agents. Some organic antibacterial agents are naturally derived, and have stronger antibacterial activity and higher sterilization speed than inorganic antibacterial agents. On the other hand, inorganic antibacterial agents have weaker bactericidal activity than organic antibacterial agents, but are characterized by the fact that they are less likely to produce resistant bacteria and have high heat resistance. Any antimicrobial substance must be safe under the environment of use. These antibacterial and antifungal agents are thought to exert their antibacterial and antifungal effects by causing cell collapse, cell death, inhibition of protein synthesis, etc., or inhibition of cell growth. there is

Patent Literature 1 discloses a polyolefin resin foam sheet having an antistatic function that provides an antistatic effect regardless of humidity conditions in the air, and that has flexibility and cushioning properties. This polyolefin resin sheet contains a polymeric antistatic agent on at least one side of the polyolefin resin foam layer at a ratio of 5 to 50 parts by weight with respect to 100 parts by weight of the base resin, and has a basis weight of 0.1 to 20 g/m. A polyolefin-based resin foam sheet in which ^two polyolefin resin layers are laminated is described.

According to the present invention, since the basis weight of the polyolefin-based resin layer containing the polymeric antistatic agent is 0.1 to 20 g/m ² , the properties of the foam layer are light, flexible and flexible. A polyolefin-based resin foam sheet excellent in cushioning properties and appearance can be obtained. It is possible to provide a multi-layer foamed sheet that has antistatic properties and that does not cause migration of low-molecular-weight components into the package. The present invention is a laminated foam structure in which a resin layer containing a large amount of a polymeric antistatic agent is laminated on the surface of a resin foam.

In Patent Document 2, polypropylene containing 10 to 25 parts by weight of a polymer type antistatic agent having a similar melt flow rate and melting point to 100 parts by weight of a polypropylene resin having a predetermined flow rate (MFR) and melting point A polypropylene resin foamed sheet obtained by extruding and foaming a resin composition, the foamed sheet has a density of 0.05 to 0.1 g/cm ³ , a thickness of 0.5 to 2 mm, and a number of cells in the thickness direction of 1 to 1. A method for producing a polypropylene-based resin foam sheet is described, which is characterized by having a density of 3 pieces/mm and a surface resistivity of less than 1×10 ¹³ (Ω/□).

The invention of Patent Document 2 is a polyolefin-based resin foam that has an extremely low possibility of contaminating the surface of a contacting partner when used as a packaging material, has an excellent appearance, and exhibits uniform antistatic properties over the entire surface. and a polyolefin resin foam. Since this invention uses a polymer-type antistatic agent, the content of the antistatic agent relative to the base resin is as large as 10 to 25 parts by mass.

Patent Document 3 discloses a polyolefin resin sheet formed of a polyolefin resin composition containing a base resin made of at least one of polyethylene resin and polypropylene resin and a polymer antistatic agent. It is disclosed that the polymeric antistatic agent contains both a polymeric antistatic agent and a polystyrene resin that are incompatible with the base resin.

In the polyolefin-based resin sheet of Patent Document 3, a polystyrene resin having low compatibility with polyethylene-based resin and polypropylene-based resin is added to form a resin sheet. It will form a dispersed phase with a “sea-island structure”. At that time, the polymer antistatic agent can be aggregated along the interface between the polystyrene resin particles and the matrix resin to improve the function of the polymer antistatic agent. In other words, the amount of the polymeric antistatic agent to be used is reduced to achieve antistatic properties. The present invention does not include a resin that is incompatible with the base resin, nor does it form a dispersed layer having a sea-island structure.

Patent Document 4 contains a polyethylene resin, a polymer antistatic agent, an anionic surfactant, and a nonionic surfactant, and the polymer type electrostatic charge is added to 100 parts by mass of the polyethylene resin. 5 to 15 parts by mass of an inhibitor, 0.1 to 5 parts by mass of an alkylsulfonate surfactant as the anionic surfactant, and 0 part by mass of a polyoxyalkylene surfactant as the nonionic surfactant. 1 to 0.5 parts by mass, and the mass ratio of the anionic surfactant to the nonionic surfactant is 1 to 10 times.

According to this invention, the foreign matter adhering to the glass of the transportation container is composed of stearic acid-based compounds with relatively high lipophilicity, and other sebum, fibers, resin fine particles, and the like. On the other hand, it is described that the combined use of an anionic surfactant and a nonionic surfactant makes it possible to remove foreign matters adhering to the glass by washing with water. This invention is an invention that removes foreign substances by using a combination of a high-molecular-weight antistatic agent and a low-molecular-weight surfactant.

In Patent Document 5, component (A): an inorganic chemical containing a transition metal. Component (D): a surfactant having an antibacterial or antifungal effect containing a predetermined amount of an agent, component (B), and two kinds of organic solvents having different boiling points as component (C), and a space for a piezo spray device using this A treatment agent is disclosed.

The component (D) disclosed in this document contains either a cationic surfactant, an amphoteric surfactant or a semipolar surfactant. includes. This invention is a piezo-type spraying device in which an inorganic agent containing a transition metal and, if necessary, a cationic surfactant, an amphoteric surfactant and an amine oxide type surfactant as a semipolar surfactant are dispersed in a solvent. It is used as a space treatment agent.

Patent Literature 6 discloses an anti-static sheet that can utilize superior antibacterial and antifungal properties without using an antistatic agent such as a surfactant or carbon black. In addition, the antistatic antibacterial curtain material of Patent Document 6 uses a fabric as a base material, and in a flexible laminate having at least one antistatic resin layer provided on this base material, the antistatic resin layer is Contains a liquid ester compound having one or more ether bonds in the molecule and a chelate complex (metal ligand), and if necessary, has an area occupation ratio of at least 20% with respect to the surface of the antistatic resin layer A coating film layer having is provided. In the antistatic sheet of the present invention, the antistatic resin layer has antibacterial and antifungal properties, and the antistatic layer contains a liquid ester compound having an ether bond and a chelate complex.

The antistatic resin composition of Patent Document 7 comprises the following components (1) and (2), wherein component (1) is a propylene copolymer consisting of (A) and/or (B) below.
(A) a ratio of 0.5 to 4.0% by weight of ethylene, 66.0 to 98.5% by weight of propylene, and 1.0 to 30.0% by weight of α-olefin having 4 to 12 carbon atoms (the A propylene random copolymer obtained by supplying the total amount of three components to a polymerization system.
(B) A propylene random copolymer obtained by supplying 2.5 to 10.0% by weight of ethylene and 90.0 to 97.5% by weight of propylene to a polymerization system (based on the total amount of the two components). and

Furthermore, component (2): one or more semipolar organic boron polymer compounds represented by a specific general formula, and one tertiary amine having a total of 5 to 82 carbon atoms and having at least one hydroxyl group. Propylene-based copolymers are disclosed comprising a species or two or more species and a polymeric charge-transfer conjugate that is the reaction product of a ratio of one boron atom to one basic nitrogen atom.

Patent Document 7 describes a reaction between a specific propylene copolymer, an organic boron polymer compound in which boron atoms are regularly incorporated in the molecule while maintaining a semipolar bond structure, and a hydroxyalkylamine. By combining the polymer charge-transfer type binder, the chargeability of the propylene copolymer is removed, and the charging tube generated instantaneously by contact, friction, application of an external voltage, etc. quickly and completely leaks. It is described that, unlike the above-mentioned antistatic agents, it is possible to produce non-static products that are durable and stable. This document is a propylene-based copolymer containing an α-olefin containing a BN type charge transfer antistatic agent.

Since the invention of Patent Document 1 is a laminated resin foam, it is necessary to have a laminated structure, the structure is complicated, and there is a problem that antistatic performance cannot be imparted to the foam layer such as the sliced surface and the cut surface in the thickness direction. There is In the case of the invention of Patent Document 2, since a polymeric antistatic agent is used, there is a problem that the content of the antistatic agent to the base resin is as large as 10 to 25 parts by mass.

In the invention of Patent Document 3, the antistatic agent contains a resin incompatible with the base resin and forms a dispersed layer having a sea-island structure. Furthermore, it does not have a sea-island structure. The invention of Patent Document 4 is an invention that removes foreign matter by using a combination of a high-molecular-weight antistatic agent and a low-molecular-weight surfactant, and does not use a BN type charge-transfer type antistatic agent. The invention of Patent Document 5 uses a semipolar amine oxide surfactant dispersed in a solvent. The N-type semipolar charge-transfer compound is not used as an antistatic agent.

The antistatic resin layer disclosed in the invention of Patent Document 6 has antibacterial and antifungal properties, but the antistatic layer does not use a BN type charge transfer type antistatic agent. Patent Document 7 is a propylene copolymer containing a BN type charge-transfer type antistatic agent and containing an α-olefin in addition to a polypropylene resin and a polyethylene resin. - It is a polypropylene resin foam containing an N-type charge-transfer antistatic agent. However, there is no description or suggestion regarding the distribution of the BN type charge-transfer type antistatic agent on the sliced surface of No. 2 or the antibacterial/spinning properties of the foam, and the effects thereof are also unknown.

Japanese Patent Application Laid-Open No. 2005-074771 Japanese Patent Application Laid-Open No. 2009-191195 JP 2011-162764 A JP 2014-136755 A JP 2017-119680 JP 2019-093624 A JP-A-01-230653

Returnable shipping containers for electronic parts, partitioning materials, and cushioning materials for packaging are designed to be used repeatedly. Due to abrasion from the product during transportation, the surface layer of the resin foam may be worn and peeled off, exposing the foam layer. A container for transportation and transportation using a resin foam that exhibits an excellent antistatic effect on both the surface of the foam and the foam layer, and at the same time, has antibacterial and antifungal properties and has a long-lasting antistatic performance. There are no container partitions or packing cushions. For this reason, development of such transport containers, partition members for transport containers, cushioning materials for packing, and resin foams used therefor has been expected.

In the present invention, in order to solve the above problems, a BN type charge transfer type antistatic agent is used, and even if the content of the antistatic agent with respect to the base resin is as small as 2.0 parts by mass or less, the resin Transportation containers using resin foam, both the surface of the foam and the surface and the inner foam layer of the resin foam having continuous antistatic performance, partitioning members and cushioning materials for packaging, and polypropylene used therefor The objective is to develop a method for manufacturing resin foam and to use these transportation container materials for antibacterial and antifungal purposes.

Furthermore, these transport containers, partition members for transport containers, and cushioning materials for packing are excellent in antibacterial and antifungal properties, and the resin foam used for them is a B—N type charge-transfer charging Using a masterbatch of polyethylene and a BN type charge transfer type antistatic agent as an inhibitor, finely dispersing the BN type charge transfer type antistatic agent inside the resin foam, and extruding and foaming. can be manufactured in In this case, low-density polyethylene (LDPE) is particularly preferable as the constituent resin of the masterbatch.

A first invention is a polypropylene resin foam containing a polypropylene resin as a base resin and a BN type charge transfer type antistatic agent in the range of 0.1 to 2.0 parts by mass with respect to the base resin. The surface of the polypropylene resin foam surface and the sliced surface of the foamed resin layer of the polypropylene resin foam surface and the sliced surface measured in accordance with JISK6911. A transport container or a partition material for a transport container having a resistivity of 1.0×10 ¹³ Ω/□ or less. Preferably, the surface resistivity of the foamed resin layer on the surface of the polypropylene resin foam and the sliced surface can be set to 5.0×10 ¹² Ω/□ or less and 3.0×10 ¹² Ω/□. Here, the BN type charge transfer type antistatic agent can be in the range of 0.1 to 1.0 parts by weight or 0.1 to 0.8 parts by weight. The antistatic agent has a sufficient effect even when it is 1.0 parts by mass or less or 0.8 parts by mass or less.

In addition, the surface resistivity of the resin foam surface measured in accordance with JISK6911 of the foamed resin layer on the surface of the polypropylene resin foam and the sliced surface is 1.0 × 10 ¹² Ω / square or less, and the surface resistivity of the sliced surface is It is also possible to obtain a transport container, a partition material for a transport container, or a cushioning material for packing, which is 5.0×10 ¹² Ω/□ or less. In addition, the transport container or the partition material or the cushioning material for the transport container is a transport container or transport container using a high-strength polypropylene resin foam having a tensile strength in the MD direction of 6.5 to 8.0 MPa. It can also be used as a partition material for containers or a cushioning material for packing, and a transport container or transport using a low-strength to high-strength polypropylene resin foam having a tensile strength in the MD direction of 5.0 to 8.0 MPa It can also be used as a partition material for a container or a cushioning material for packing. The strength in the MD direction of the high-strength transport container or the partition material of the transport container or the cushioning material for packaging is preferably 6.8 to 7.6 MPa, and the strength range from low strength to high strength is desirable. is 5.5 to 7.6 MPa.

Further, the polypropylene resin foam used for the transport container or the partition material of the transport container contains 0.3 to 8.0 parts by mass of polyethylene resin with respect to 100 parts by mass of the polypropylene resin. It may be a partition material or a cushioning material for a container for transportation or a container for transportation.

The polypropylene resin foam used for a transport container, a partition material for a transport container, or a cushioning material for packaging contains 0.3 to 10 parts by mass of a polyethylene resin, and further contains a white pigment, a yellow pigment, a blue pigment, a green pigment, and a red pigment. , black pigment in the range of 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the polypropylene resin. Here, when the pigment is contained in the resin foam, if the content of the pigment is small, the polyethylene resin may be added together as a masterbatch of the polyethylene resin and the pigment.

A transport container or a partition material for a transport container, wherein the pigment is a metal phthalocyanine-based compound, and the metal phthalocyanine compound is a pigment of any one of Cu, Co, Fe, and Ni metal phthalocyanine-based compounds; It may be a cushioning material for packing.

The transportation container or the partitioning material or the cushioning material for the transportation container is an antibacterial or antifungal transportation container or the partitioning material for the transportation container or the cushioning material for packaging, or It may be a partition material for a transportation container or a cushioning material for packing.

In the second invention, the content ratio of the BN type charge transfer type antistatic agent with respect to the total weight of the master batch of the BN type charge transfer type antistatic agent and the polyethylene resin with respect to 100 parts by mass of the polypropylene resin is Add 0.4 to 10 parts by mass or less of a masterbatch of 1/4 times or less to 100 parts by mass of the base polypropylene resin, perform melt kneading, perform gas foaming during melt kneading, and polypropylene A transport container or transport containing 0.3 to 8.0 parts by mass of a polyethylene resin and 0.1 to 2.0 parts by mass of a B—N charge transfer type antistatic agent with respect to 100 parts by mass of the resin A transportation container or a method for producing a polypropylene resin foam for a partitioning material of a transportation container or a packaging cushioning material, characterized by producing a polypropylene resin foam for a partitioning material for a container or a cushioning material for packaging.

The polypropylene resin foam contains 0.3 to 10 parts by mass of the polyethylene resin, and further contains 0.5 to 4.0 parts by mass of the pigment with respect to 100 parts by mass of the polypropylene resin, and the pigment is A transportation container, a partition material for a transportation container, or a buffer for packing, which is a metal phthalocyanine compound, and the metal phthalocyanine compound is a pigment of any of the metal phthalocyanine compounds of Cu, Co, Fe, and Ni. It may be a method for producing a polypropylene resin foam for material.

A method for producing a polypropylene resin foam for use as a transportation container, a partition material for a transportation container, or a cushioning material for packaging may be employed, wherein the polyethylene resin forming the masterbatch is low-density polyethylene.

A third aspect of the present invention is a transport container or a transport container using the polypropylene resin foam produced by the method for producing a polypropylene resin foam for a transport container, a partition material for a transport container, or a cushioning material for packaging. It is used for antibacterial and antifungal applications for partition materials and cushioning materials for packaging.

According to the present invention, a transport container using a polypropylene resin foam having sustained antistatic performance on the surface of the foam and the foam layer inside the foam, a partition member and a cushioning material for packing, and the same It is possible to realize the use of the manufacturing method, the transport container, the partition member of the transport container, and the cushioning material for packing for antibacterial and antifungal purposes.
The product of the present invention not only has excellent antistatic performance, but also excellent antibacterial and antifungal properties. By adding a polar BN type charge transfer type antistatic agent in a small amount of 2.0 parts by mass or less to the resin foam, a sufficient sustained antistatic effect is obtained on both the surface and the sliced surface of the resin foam. It becomes possible to obtain an antibacterial and antifungal effect on the foam.

In addition, in the present invention, as a method for producing the resin foam used in these products, a masterbatch of polyethylene (especially low-density polyethylene) and a BN-type charge transfer antistatic agent is used to achieve a good foaming state and electrification. This is realized based on the ability to obtain a dispersed state of the inhibitor. Transportation containers, partition members and packing cushioning materials for transportation containers, manufacturing methods thereof, and enabling the use of these products for antibacterial and antifungal purposes, and at the same time reducing the amount of antistatic agents, Achieved cost reduction.

[Polypropylene resin foam]
The polypropylene resin foam for use as a transport container or a partition material for a transport container or a cushioning material for packaging according to the present invention is excellent in antistatic properties containing a polypropylene resin and a B—N type charge transfer type antistatic agent. Polypropylene foam. That is, the polypropylene resin foam of the present invention is a foam sheet formed using a resin composition containing at least a polypropylene resin and a BN type charge-transfer type antistatic agent. In addition, the polypropylene resin foam of the present invention may contain a cell nucleating agent in order to stabilize foamability.

<Polypropylene resin>
The polypropylene resin used as a raw material for the polypropylene resin foam for the transport container, the partition material of the transport container, and the cushioning material for packaging of the present invention is obtained by using propylene as a monomer and polymerizing it by a conventional method. can be done. In addition, the polypropylene resin used as the raw material can be used by appropriately blending homopolymers, block polymers, random polymers, etc. having various structures in order to adjust the performance of the polypropylene resin foam. For example, if the base resin contains a large amount of a homopolymer with high melt tension, the melt tension of the polypropylene resin is improved, the proportion of open cells in the polypropylene resin foam is reduced, and the proportion of closed cells is increased. , a high-strength polypropylene resin foam can be obtained.

Further, the tensile strength, elongation value, flexural strength, flexural modulus, tear strength, etc. in the tensile test of the polypropylene resin foam for the transport container, the partition material of the transport container, and the cushioning material for packaging of the present invention are It is controlled by the selection and mixing ratio of polypropylene resins with various structures used as the raw material, the amount of cell nucleating agent added, the amount of carbon dioxide injected during melt kneading during extrusion, and the pressure adjustment during injection. becomes possible.

For example, the polypropylene resin used in the present invention is commercially available. As described above, in order to adjust the tensile strength, flexural strength, flexural modulus, tear strength, etc. in the tensile test of the polypropylene resin foam, it is also possible to adjust by blending the homopolymer and the block polymer. It is possible. In order to achieve the above mechanical properties of high strength and high rigidity, the content of the homopolymer should be increased and the foaming conditions should be controlled to increase the ratio of closed cells to open cells.

<BN type charge transfer type antistatic agent>
The BN type charge transfer antistatic agent is a BN complex structurally designed to be compatible with a non-polar resin, with the main chain part held as an anchor in the target resin matrix, Polar moieties (BN) are anchored to the surface. This antistatic agent is composed of an organic nitrogen compound that corresponds to the (−) charge and erases the N component and a B component (semipolar organic compound) that corresponds to the (+) charge and erases It is composed of a boron compound), and simultaneously with the generation of static electricity, it undergoes a charge-transfer transition and instantly transforms into an ion-pair structure.

In addition, the BN type charge transfer antistatic agent has a structure in which the (B) component and the (N) component are integrated and have three alkyl groups. If (-CH ₂ -) is present, it has the property of existing as fine particles stably dispersed inside by activating the Fader Waals force, so it can be used as a high-molecular-type antistatic agent in a polymer blend system. In contrast, it is said that antistatic performance can be obtained by adding a small amount because of its excellent compatibility and dispersibility with polyolefin resins such as polyethylene and polypropylene.
The BN type charge transfer type antistatic agent is preferably a compound represented by the following general formula (1).

〔式中、Ｒ^１およびＲ^２はそれぞれ独立に炭素数１～２４のアルキル基を表す。Ｒ^３およびＲ^４はそれぞれ独立に水素原子または炭素数１～４のアルキル基を表す。Ｒ^５は炭素数１～１２のアルキレン基を表す。Ｒ^６は炭素数１～２４のアルキル基を表す。Ｒ^１～Ｒ^６はさらに発明の効果を奏する範囲で任意の置換基（ヒドロキシル基等）を有していてもよい。また、発明の効果を奏する範囲で、アルキレン鎖（ＣＨ_２）の一部が酸素原子（Ｏ）、カルボニル基（ＣＯ）、イミノ基（ＮＨ）に置き換わった構造を取っていてもよい。〕
Ｂ－Ｎタイプ電荷移動型帯電防止剤は、なかでも、下記式（２）で表される化合物であることが好ましい。

[In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 24 carbon atoms. R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R ⁵ represents an alkylene group having 1 to 12 carbon atoms. R ⁶ represents an alkyl group having 1 to 24 carbon atoms. R ¹ to R ⁶ may further have any substituent (hydroxyl group, etc.) within the scope of achieving the effects of the invention. In addition, a structure in which a part of the alkylene chain (CH ₂ ) is replaced with an oxygen atom (O), a carbonyl group (CO), or an imino group (NH) may be employed within the scope of the effects of the invention. ]
The BN type charge transfer type antistatic agent is preferably a compound represented by the following formula (2).

Antistatic agents using boron include donor-acceptor type molecular compound type antistatic agents, ion pair compound type antistatic agents by neutralization reaction, and hybrid type antistatic agents of semi-polar organic boron compounds and polar charge substances. There are various antistatic agents, but in the present invention, BN105, a BN type charge transfer antistatic agent manufactured by Boron Laboratory Co., Ltd., is used as the donor-acceptor molecular compound type antistatic agent. bottom. The reason why BN105 is used in the present invention is that it has excellent dispersibility in polyolefin resins such as polypropylene having methylene groups.
Here, BN105 is a 1:1 molecular compound consisting of the nonionic compounds of the (B) component and the (N) component. And it has the effect of eliminating static charges inside. Therefore, a transition reaction occurs in which protons are transferred from the donor B compound to the acceptor N compound. As a result, charges are neutralized and eliminated on the surface of the resin foam, and charges are removed by transport of holes by B and diffusion of electrons by N on the surface other than the surface. becomes possible.

As the content of the BN type charge transfer type antistatic agent, the amount of the BN type charge transfer type antistatic agent added to 100 parts by mass of the polypropylene resin is 0.1 to 2.0 parts by mass. It can be added within the range of 0.1 to 1.0 parts by mass, and a sufficient antistatic effect can be obtained. When aiming for a surface resistivity of 1.00×10 ¹³ Ω/□ or less, the above addition amount is sufficient.
Surprisingly, it was found that the BN type charge-transfer type antistatic agent exerts an antibacterial effect (see Table 1, test materials 1 to 10). There is no literature disclosing that the BN type charge transfer type antistatic agent exhibits an antibacterial effect, and the BN type charge transfer type antistatic agent is incorporated into a polypropylene foam to exhibit antibacterial properties and to demonstrate the effect. The "transportation container", "transportation container partition material", and "packing cushioning material" that are used are constructed based on the above findings and have philosophically new features. is.

<Master batch of BN type charge transfer antistatic agent>
In order to maximize the performance of the BN type charge transfer type antistatic agent, unlike the surfactant type low molecular weight antistatic agent, it does not involve bleeding out to the surface of the foam, It is important to control the state of dispersion of the BN type charge transfer antistatic agent.

As the BN type charge transfer type antistatic agent, a polypropylene resin is used in which a predetermined amount of a masterbatch in which a BN type charge transfer type antistatic agent is dispersed in a low density polyethylene (LDPE) resin is mixed with polypropylene. be able to. Here, the masterbatch can be produced by mixing and extruding a low-density polyethylene and a BN type charge-transfer type antistatic agent, followed by cutting.

In the master batch, the mixing ratio of polyethylene and the BN type charge transfer type antistatic agent can be a predetermined ratio, but considering the dispersibility of the BN type charge transfer type antistatic agent, at least polyethylene resin The mixing ratio of the B—N type charge-transfer type antistatic agent in (1) is desirably 3 times or more. More preferably, it is 4 times or more, or 5 times or more, and 7 times or less. In terms of the content ratio of the BN type charge transfer type antistatic agent to the total weight of the masterbatch of the BN type charge transfer type antistatic agent and the polyethylene resin, it is 1/8 or more and 1/4 or less. is preferred.

Here, the reason why the lower limit of the ratio of the resin component constituting the masterbatch is set to 3 times or more and 8 times or less is that a stable masterbatch with a uniform composition cannot be obtained if the resin component is small. When the mixing ratio of the resin component is high, the mixing amount of the resin to be mixed in the masterbatch with respect to the polypropylene resin of the base resin of the resin foam is large in order to obtain the same content of the BN type charge transfer type antistatic agent. As a result, the content of the resin component introduced from the masterbatch to the resin foam increases, which affects the strength and heat resistance of the polypropylene resin foam itself.

The masterbatch can be produced in-house, but commercially available polycol or the like can also be used. Here, the mixing ratio of the polyethylene and the BN type charge-transfer type antistatic agent in the masterbatch can be appropriately adjusted within the above range, but the preferable range is 3 times or more and 7 times or less (of the masterbatch). The proportion of BN type charge transfer antistatic agent to total weight ranges from 4:1 to 8:1). Here, as the base resin of the masterbatch, polyethylene resin such as low-density polyethylene and high-density polyethylene, as well as polypropylene resin can be used.

<Other resin components>
The base resin is a polypropylene resin, but if it is a small amount other than the polypropylene resin, the polyethylene resin as the other resin component is in the range of 0.3 parts by mass to 8.0 parts by mass with respect to 100 parts by mass of the polypropylene resin. may be included in For example, in order to uniformly disperse a BN type charge transfer antistatic agent in a polypropylene resin, it is desirable to prepare a masterbatch mixed with a polyethylene resin.

Here, the reason why the content of the polyethylene resin introduced from the antistatic agent masterbatch to the polypropylene resin is set to 8.0 parts by mass or less is that when the content of the polyethylene resin introduced from the masterbatch increases, the polypropylene resin foams. Mechanical properties such as tensile strength, flexural strength, flexural modulus, and tear strength and heat resistance are reduced, so the upper limit of polyethylene resin for polypropylene resin in polypropylene resin foam is 8.0 parts by mass. preferably 6.0 parts by mass or less, particularly preferably 4.0 parts by mass or less. Here, considering the content of the polyethylene resin introduced from the pigment masterbatch described later, the content of the polyethylene resin is allowed up to 10 parts by mass in total. Since the lower limit of the content of polyethylene resin depends on the mixing ratio of the base resin of the masterbatch to 0.1 part by mass, which is the lower limit of the BN type charge-transfer antistatic agent, the dispersing effect of the buster. is preferably 0.3 parts by mass or more, particularly preferably 0.4 parts by mass or more, and particularly preferably 0.6 parts by mass or more.

Here, there is no particular problem if the mixing ratio of the masterbatch resin and the BN type charge transfer antistatic agent is in the range of 3: 1 to 7: 1, so in the present invention, the transport in the present invention 0.1 to 2.0 parts by mass of a resin foam or a BN type charge transfer type antistatic agent as a material for use as a partition material for a container or a shipping container or a cushioning material for packaging, and a masterbatch The content range of the BN type charge-transfer type antistatic agent and the polyethylene resin as the base resin is adjusted within a range that does not inhibit the inclusion of 0.3 to 8.0 parts by mass of the polyethylene resin as the base resin. As long as it is satisfactory, the mixing ratio of the masterbatch is 3:1 to 7:1, which is the entire range of the composition range of these BN type charge transfer type antistatic agents and the composition range of the polyethylene resin of the base resin. There is no particular problem even if the above mixing ratio cannot be applied over the region, and the mixing ratio of the masterbatch may be appropriately adjusted so as not to exceed the above composition range. Needless to say, this corresponds to a ratio of 4:1 to 8:1 of the BN type charge-transfer type antistatic agent to the total weight of the masterbatch.

<Bubble nucleating agent>
The polypropylene resin foam of the present invention contains a cell nucleating agent. This cell nucleating agent promotes the formation of cell nuclei when the resin is foamed in the sheet manufacturing process, and improves cell miniaturization and uniform dispersibility. The cell nucleating agent used in the present invention is not particularly limited, and for example, sodium bicarbonate, ammonium bicarbonate, sodium bicarbonate citric acid, azodicarbonamide, talc, etc. can be used as the cell nucleating agent.

In addition, the present invention is not limited to these, and can be widely applied to those commonly used in resin foaming. Here, the content of the cell nucleating agent may be about 0.5 to 2.0 parts by mass with respect to 100 parts by mass of the polypropylene resin, but usually about 1 part by mass is sufficient.

<Other additives>
(pigment)
The polypropylene resin foam of the present invention may contain additives such as pigments, heat resistance improvers, flame retardants, etc., as long as the effects of the present invention are not impaired. A pigment is used to color the polypropylene resin foam sheet. Mainly used pigments include white pigments, yellow pigments, blue pigments, green pigments, red pigments and black pigments.

Specific examples of these pigments include white pigments such as titanium oxide, lead white, and antimony oxide; yellow pigments such as yellow lead, zinc yellow, chrome yellow, cadmium yellow, and other inorganic yellow pigments; and blue pigments. organic metal pigments such as Cu phthalocyanine and Co phthalocyanine; green pigments such as phthalocyanine green (highly chlorinated Cu phthalocyanine); Red is used. Moreover, carbon black etc. can be used as a black pigment. In addition to the above, other phthalocyanine pigments include Ni phthalocyanine for dark blue, Fe phthalocyanine for dark purple, green and black, and these phthalocyanine pigments may also be used.

Among the above pigments, titanium oxide (rutile type) or carbon black can be used as the heat resistance imparting member when heat resistance is to be imparted. This is because titanium oxide has high heat resistance and excellent heat reflectivity, and carbon black has high heat resistance and excellent thermal conductivity.

Further, when a pigment composed of an organic metal complex such as phthalocyanine blue or phthalocyanine green is used, antibacterial and antifungal properties can be expected. Although the reason for this has not been completely elucidated, phthalocyanine-based pigments such as Cu, Co, Ni, and Fe phthalocyanines have an oxidizing action, which contributes to the formation of cells of fungi and molds. It is presumed that by inhibiting metabolism, it exerts its antibacterial and antifungal effects.

It should be noted that the antibacterial effect of pigments has been unclear in the past, and it has been more unclear whether it functions in polypropylene resin foams. In particular, according to the present invention, in specific pigments such as phthalocyanine pigments, the long-lasting antistatic effect of the coexisting BN type charge-transfer antistatic agent is not impaired, while the foam is extremely It is a new finding of the present invention that a good antibacterial effect can be obtained.

Here, the content of these pigments is desirably in the range of 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the polypropylene resin. The reason why the upper limit of the content of the pigment is 4.0 parts by mass is that 4.0 parts by mass is sufficient to obtain the desired coloring state as a product when considering the intended use as a pigment. Because it is. The reason why the lower limit of the content is 0.5 parts by mass is that if the content is less than 0.5 parts, the coloring may be insufficient. Therefore, the preferred amount of pigment to be added is 0.5 to 4.0 parts by mass. It is desirable to use the content in the range of 0 parts by mass. Further, even when titanium oxide, carbon black, or the like is used for improving heat resistance, the range of addition amount of these pigments is the same as described above. Here, the pigment is added in principle by direct blending, but when the amount of pigment added is small, masterbatch addition may be used.

(Flame retardants)
The transport container or the partition material or packing cushioning material of the transport container is a polyolefin resin foam containing a flame retardant such as an antimony flame retardant, a hydroxide flame retardant, or a bromine flame retardant. There may be. In addition, when the said polypropylene resin foam contains a flame retardant, as for content of a flame retardant, 4.0 mass parts or less is desirable. If the content of the flame retardant is 4.0 parts by mass or less, there is no concern that foaming will be inhibited. This is because a certain degree of flame retardancy can be ensured if the amount of the flame retardant added is in the range of 1.0 to 4.0 parts by mass.

<Production of polypropylene foam sheet>
In an extruder with a cylinder diameter of 150 mm, a polypropylene resin (component (A)) and a masterbatch (B) containing a B—N charge transfer type antistatic agent component (preferably 0.4 to 8.0 parts by mass, based on material polypropylene resin 100 parts by mass) were added in a predetermined ratio and kneaded. Carbon dioxide gas is extruded from the center of the tip of a T-shaped foaming die with a width of 400 mm at a predetermined gas pressure and gas flow rate from the cylinder part in the middle of the extruder, and the kneaded material is passed between two sets of horizontally installed forming roll dies. let it pass. By adjusting the rolling rate in this manner, a polypropylene resin foam sheet having a predetermined thickness can be obtained. This polypropylene resin foam sheet can be produced at an extrusion temperature of 160 to 195° C. and by rolling in the MD direction with a forming roll die at a rolling rate of 20 to 90%. In addition, an air bubble nucleating agent, a pigment, or the like can be added at a predetermined ratio as necessary.

<Product thickness of resin foam>
The polypropylene foam of the present invention is sheet-like, and the thickness of the foam sheet is appropriately designed according to the purpose. For example, it can be a foam sheet with a thickness of 1.0 to 5.0 mm. The thickness of the foamed sheet having these thicknesses can be appropriately adjusted by appropriately setting the rolling rate for extrusion and subsequent rolling of the sheet. As will be described later, in the examples of the present invention, the sheet thickness of the foam was standardized at 3.0 mm.

<Structure of resin foam>
The polypropylene resin foam used in the present invention preferably has an expansion ratio of 1.5 to 4 times. Predetermined strength and elongation values can be obtained by setting the expansion ratio to 1.5 to 4 times. This expansion ratio is more preferably 1.5 to 3.3 times. Here, in the case of a resin foam obtained by rolling a polypropylene resin foam with a low expansion ratio using a forming roll die, as in the present application, if the expansion ratio is almost the same, the tensile strength and elongation value are different depending on the type of base resin. In addition to this, the orientation of the resin also has an effect.

Further, the polypropylene resin foam used in the present invention is adjusted to have an open cell rate of 10 to 60%. By adjusting the open cell ratio to 10 to 60%, it is possible to appropriately adjust the tensile strength, elongation value, flexural modulus, flexural strength, compressive strength, etc. of the polypropylene resin foam to predetermined values. Become. Therefore, in order to avoid crushing of the resin foam as much as possible and to set a predetermined compression strength higher, or to give a predetermined tensile strength, bending strength, or a predetermined bending elastic modulus, polypropylene resin foam It is preferable that the open cell ratio of is small to a certain degree and that the number of closed cells is large. Here, the open cell ratio can be adjusted by appropriately adjusting the strain hardening property at high temperatures, the melt tension, the amount of gas during extrusion foaming, and the like.
Here, a high-strength material can be obtained when the open-cell rate is around 10%, and a low-strength material can be obtained when the open-cell rate is around 60%. The open cell ratio can be adjusted by adjusting the melt tension of the base resin constituting the resin foam.

The cells of the polypropylene resin foam of the present invention are stretched in the MD direction by rolling, and are reduced in diameter in the thickness direction of the sheet, so that the cells have a flat shape extending in the MD direction. Therefore, the bubble diameter in the thickness direction is reduced, and the bubble density in the thickness direction is increased. The polypropylene resin foam sheet preferably has a bubble density (cell density) of 1.0×10 ³ to 3.0×10 ³ cells/mm ³ , and the bubble density means that the cells are relatively small. When the cell diameter is large, coalescence of cells is likely to occur during production of the polypropylene resin foam sheet. Stress concentrates in the vicinity of coalesced bubbles, and local deformation tends to occur, and the tensile elongation at break tends to decrease.

<Surface resistivity>
3. The polypropylene resin foam according to the present invention has a surface resistivity of 1.00×10 ¹³ Ω/□ or less, and preferably 5.00×10 ¹² Ω/□ or less on its surface and sliced surface. It is more preferably 00×10 ¹² Ω/□ or less, and particularly preferably 1.00×10 ¹² Ω/□ or less. Since the lower the surface resistivity of the product, the better. Therefore, it is not considered necessary to set the lower limit value for ^the product ^. Ω/□ or more is desirable.

According to a preferred embodiment of the present invention, it is possible to provide a transportation container having excellent antistatic performance using a polypropylene foam, a partition material for the transportation container, and a cushioning material for packing. When an antistatic agent is contained in the resin that constitutes the foam, the foam has a skin layer and a foam layer where there are no air bubbles near the foam surface, so the type of antistatic agent and the manufacturing process Depending on the method of adding the antistatic agent, the antistatic performance may differ due to differences in the distribution of the antistatic agent between the antistatic agent skin layer and the foam layer, and differences in the antistatic mechanism due to the difference in the antistatic agent. . In addition, in general, the foam layer may increase the surface resistivity used for evaluating antistatic performance due to the air layer of the bubbles, and the antistatic performance may decrease. For the purpose of partitioning materials for containers and transportation containers and cushioning materials for packing that can be used for a long period of time, the skin layer on the surface of the foam and the foam layer have excellent surface resistivity on the sliced or cut surface and can be used for a long period of time. A product and its manufacturing method and its use for antibacterial and antifungal applications can be provided. The product developed according to the preferred embodiment was excellent not only in antistatic performance but also in antibacterial and antifungal properties.

In addition, the product according to the preferred embodiment of the present invention can maintain antistatic performance even when the foam layer is exposed due to wear or damage on the surface of the product, and the growth of bacteria and mold on the surface of the product can be prevented. By suppressing , it is possible to sufficiently suppress the deterioration of products and the occurrence of defects caused by these factors.

As described above, the polypropylene resin foam of the present invention can be used as a transport container, a partition material for a transport container, or a cushioning material for packing. Objects such as transportation are not particularly limited, but examples include electronic component applications. By using the transport container, the partition material for the transport container, or the cushioning material for packing according to the present invention, the generation of static electricity can be suppressed and the quality of electronic parts and the like can be favorably maintained. In particular, since the surface resistivity of the sliced surface is excellent, the transport container, the partition material of the transport container, and the cushioning material for packing of the present invention can be used as a returnable container, and furthermore, have antibacterial and antifungal properties. It is also suitable for use as an antibacterial and antifungal agent, and at the same time, it is possible to provide a method for producing these products.

<Manufacturing method of test material>
Test material 1 to test material 21 used in the examples were obtained by adding a predetermined amount of pigment to a resin component obtained by adding a BN type charge transfer type antistatic agent to the base resin of each test material if necessary. Then, 1 part of a cell nucleating agent is added, and carbon dioxide gas is expanded three times under the conditions of a gas pressure of 7 kg/cm ² and a gas flow rate of 5 l/min. After extrusion to a sheet thickness of 4.5 mm, roll Rolling was performed at a roll interval of 2.8 mm to finish a polypropylene resin foam having a thickness of 3.0 mm. Here, polystyrene manufactured by Eiwa Kasei Kogyo Co., Ltd. was used as the bubble nucleating agent.
The BN type charge transfer antistat was added via a master patch. Here, each test material uses BN105 manufactured by Boron Laboratory Co., Ltd. as an antistatic agent, uses polyethylene or polypropylene as a base resin, and contains a BN type charge transfer type antistatic agent in a predetermined proportion. The batch was melt-kneaded, extruded into a strand having a predetermined cross-sectional shape, and then cut to a predetermined size for in-house production.

<Method of testing and measuring test material>
Regarding the test material of Example 1 described later, measurement of tensile strength by tensile test, measurement of foaming ratio, measurement of open cell rate, surface resistivity of the surface and sliced surface of the resin foam 7 days and 30 days after manufacturing the test material , the charging half-life of the surface of the foam, and the antibacterial evaluation test were carried out. Each test of tensile strength, foaming ratio, open cell ratio, surface resistivity, half-life of charging, and antibacterial test was conducted according to either JIS or ASTM standards.
Here, the material used for measuring the surface resistivity of the sliced surface was foamed at the center of the thickness direction of the resin foam with a thickness of 3 mm and the position corresponding to (1/4) of the sheet thickness of the foam on the surface. A specimen cut parallel to the body surface and processed into a test piece of a predetermined size was used.
Here, in Example 2, among the above measurement items of surface resistivity, the surface resistivity is measured only on the surface of the foam for all test materials, and the surface resistivity of the sliced surface is measured for a specific material described later, Other characteristics were measured in the same manner as in Example 1. In addition, as Example 3, in order to evaluate the antistatic performance of the representative material of Example 1 after a long period of time, the surface resistivity was measured only on the surface of the test material after holding it in a constant temperature bath at 60 ° C. for 35 days. An accelerated test was performed. In Example 3, only long-term property evaluation of surface resistivity was additionally performed, and the test material used in Example 3 overlapped with the test material of Example 1, so other than surface resistivity I didn't do the test because I didn't need to do it. In addition, the tensile strength, expansion ratio, and open cell ratio are measured for each of three test pieces, and the average value is used as the measured value. Taking this into consideration, measurements were made for each of the five test pieces, and the average was used as the measured value. The surface quality was evaluated by visual inspection of the resin foam surface of each test material, and the foamability was evaluated using a cut surface of the resin foam.
Here, in the description of each example in the tables to be described later, low-density polyethylene, high-density polyethylene, polypropylene, etc. are sometimes described in a simplified manner as LDPE, HDPE, PP, etc. in the tables of the examples, The direct blending method and the masterbatch method are indicated as DB and MB as the pigment charging method. The pigment masterbatch was produced in the same manner as the BN type charge transfer antistatic agent.

(Tensile strength)
The tensile elongation at break of the resin foam was determined according to JISK6767. More specifically, a No. 2 dumbbell test piece (thickness 3 mm) is used as the test piece, and a tensile test is performed at a tensile speed of 100 mm / min until the test piece breaks. The tensile strength was obtained in both the MD direction and the TD direction, rounded off to two decimal places, and the measurement results were reported to one decimal place.

(Expansion ratio)
The expansion ratio is a value obtained by dividing the specific gravity of the resin before foaming by the specific gravity of the foam measured by the water substitution method (JISK7112). The specific gravity of the foam can be measured using an electronic balance AG204 manufactured by Metradred. For the measured value, the value rounded to the second decimal place was used as the foaming ratio. As a result of measuring the expansion ratio for each test material of Examples 1 and 2, the expansion ratio satisfied the expansion ratio of 3.0 ± 0.1 times (2.9 to 3.1 times) for each test material. 1 and Table 2 are omitted.

(Continuous cell rate)
The open cell rate (continuous rate) was determined according to the method described in ASTM D-2856-87. Specifically, the open cell ratio was determined by applying the measured value using an air comparison type hydrometer Model 1000 (manufactured by Tokyo Science Co., Ltd.) to the following formula. The open cell ratio was calculated to two digits after the decimal point, was measured for three test materials, was rounded off, and was obtained to one digit after the decimal point to obtain the open cell ratio.
[Open cell ratio (%)] = 100 × [(apparent volume - volume value by air comparison type hydrometer) / apparent volume]

(Measurement of surface resistivity)
Surface resistivity can be measured according to JISK6911. The surface resistivity measurement uses a main electrode, a ring electrode, and a counter electrode, applies a voltage source Vs to the ring electrode, and measures the current Im flowing on the sample surface from the ring electrode toward the main electrode. Here, the surface resistance value Rs can be calculated from Rs=Vs/Im.
Here, since the current flowing from the ring electrode to the counter electrode does not flow into the ammeter, it does not affect the measured current.

Let L be the average length of the outer diameter of the main electrode and the inner diameter of the ring electrode, and W be the distance between the outer diameter of the main electrode and the inner diameter of the ring electrode. Here, the test piece is pretreated at 20±2° C. and 65±5% humidity before the measurement.
ρs = (L / W) · Rs = (Π (D + d) / (D - d)) · (Vs / Im)
Surface resistivity: ρs
Inner diameter of ring electrode: D
Outer diameter of main electrode: d
Average length of outer diameter of main electrode and inner diameter of ring electrode: L = (D + d)/2
Distance between outer diameter of main electrode and inner diameter of ring electrode: W=(D−d)/2
Surface resistance: Rs
The surface resistance measurement rate is expressed in Ω/□ and expressed as a resistance value per 1 cm ² .
In the actual measurement, a test piece of 100 mm×100 mm was cut out, and this was measured using a test apparatus with an inner diameter D of the ring electrode of 70 mmφ and an outer diameter d of the main electrode of 50 mmφ. R8340 manufactured by ADVANTEST Co., Ltd. was used as a testing device.

(Charging half-life measurement)
The charging half-life was measured with a static honesty meter by cutting out a test material having a sample size of 45 mm×45 mm for each test material under the following conditions.
Test method: JISL1094A method compliant Test conditions: Applied voltage; -10 kV
Application time; 30 s
Fixed number of test pieces: 3 Sample holding conditions: 23°C ± 2°C, 50% RH ± 2RH x 24h
Test environment: 23°C ± 2°C, 50% RH ± 2RH
Measuring device: Static Honestmeter Type H-011 (manufactured by Shishido Static Electricity Co., Ltd.)

(Method for evaluating surface quality and foamability of resin foam)
Here, when considering the use of the transport container of the product of the present invention, or the partition material for the transport container or the cushioning material for packing, the surface quality of the resin foam of these products becomes a problem. Therefore, since it is known that the surface quality of each test material is influenced by the stability during foaming, the relationship between surface quality and foamability was confirmed. The surface quality is evaluated by visual inspection. If the surface condition of the resin foam is uniform, "◎" is given, and if the surface of the resin foam is slightly uneven, there is no problem as a product. ○”, and “x” when the foam has irregularities on the surface and uneven plate thickness. In addition, to check the state of foaming, the cross-section of the resin foam in the thickness direction was examined with a scanning electron microscope at a magnification of 50 times. When the foaming state was uniform regardless of the observation site, it was evaluated as "◯".

(Antibacterial evaluation method)
In the test, an Escherichia coli kit manufactured by Microbiologics was inoculated into a liquid bouillon medium, cultured overnight in a constant temperature bath at 37° C., and the cultured bacterial solution adjusted to an appropriate concentration was used as the bacterial solution. Here, the medium used for the antibacterial test was a compact dry EC medium manufactured by Nissui Pharmaceutical Co., Ltd.

Here, the evaluation of the antibacterial properties was performed only for the skin layer on the foam surface of the test materials in Tables 1 and 2, which will be described later. The antibacterial evaluation test on the test material surface of each test material was carried out simply on only the antibacterial test piece without evaluating the untreated test piece with reference to JISZ 2801. Specifically, the target test piece was cut into a size of 50±2 mm square, and the test piece was brought into contact with the bacterial solution and allowed to stand at 37° C. for 24 hours. Thereafter, washing-out dilution was performed to a predetermined concentration, and the test solution after washing-out dilution was cultured for one day (37°C for 24 hours), and then the number of colonies of viable bacteria was measured. This operation was performed on each test piece, and the smaller the colony count of viable bacteria, the higher the antibacterial activity was evaluated.

Here, the number of colonies is calculated by multiplying the number of colonies actually measured by the dilution factor, and thus is 10 ⁶ times the actual measured value. The measurement is performed with 5 petri dishes, and the average value of the measured values of the 5 petri dishes is rounded off to obtain the measured value, which is 10 ⁶ times this value. In the tables of the examples described later, the mean values of the Cn measured values omitting 10 ⁶ are described. Since the activity value is not determined in this application, it is considered sufficient to simply compare the measured values of each test material relative to each other.
Cn: number of colonies (average number of colonies in the petri dish used)
At: Dilution ratio (Dilution ratio of the diluted solution dispensed into the adopted petri dish: 10 ⁶ )
Ct = Cn x At = Cn x ¹⁰⁶

<Example 1>
(test material)
Tensile strength in MD direction and TD direction in tensile test with No. 2 dumbbell test piece of various polypropylene resin foams about test material 1 to test material 11, open cell rate, foam surface on 7 days and 30 days after production The measurement results of the surface resistivity of the sliced surface, the charging half-life measurement results by a static honesty meter, and the evaluation results of foamability and antibacterial properties are shown.
Here, the surface resistivity was not measured immediately after the product was manufactured, but after 7 days and 30 days. In order to give In consideration of this, it was decided to measure the surface resistivity after about one week had passed.

Here, test material 1 to test material 7 are masterbatches produced by mixing a BN type charge transfer type antistatic agent with a predetermined ratio of low density polyethylene and a BN type charge transfer type antistatic agent. Using, the composition range of the masterbatch is 0.3 to 8.0 parts by mass of the polyethylene resin and 0.1 to 2.0 parts by mass of the BN type charge transfer type antistatic agent, and the polyethylene resin and A resin foam was produced using a masterbatch in which BN type polyethylene resins were mixed at a mixing ratio of 3:1 to 7:1. Here, the lower limit of the polyethylene resin is 0.3 parts by mass, which is the lower limit of the mixing ratio in the masterbatch. is 8 parts by mass, and it is necessary to adjust the mixing ratio of the aster batch to 10 parts by mass even when a pigment or the like, which will be described later, is contained. As each test material, BN105 manufactured by Boron Laboratory Co., Ltd. was used by in-house production of a masterbatch of a predetermined ratio using polyethylene or polypropylene as a base resin. Test material 8 is a test material using high-density polyethylene (HDPE) as the base resin of the masterbatch of the charge-transfer antistatic agent, and test material 9 is the masterbatch of the charge-transfer antistatic agent. This test material uses polypropylene as the base resin. Both are test materials containing the same content of 1 part by mass of the BN type charge-transfer type antistatic agent although the base resin of the masterbatch is different from that of the test material 3. Here, the resin used as the base resin of the masterbatch is F218-O manufactured by Sumitomo Chemical Co., Ltd. for low-density polyethylene, HD1300 manufactured by Nippon Polyolefin Co., Ltd. for high-density polyethylene, and Prime Polymer Co., Ltd. for polypropylene. were used, respectively.

Here, the base resin A used in the test material of Example 1 is obtained by adding a homotype polypropylene and a block type polypropylene resin at a predetermined ratio (2:1), and the base resin B is a block type. Only the base resin is blended. Both have different material strength characteristics and open cell ratio due to the difference in the base resin. Base resin A is a high-strength resin foam, and base resin B is a low-strength resin foam. Here, in the test materials 1 to 9, the base resin A was basically used as the base resin, but only the base resin B was used in the test material 4.
The homotype polypropylene used for the base resins A and B of the resin foam is MFX8 manufactured by Nippon Polypropylene Co., Ltd., and the block type polypropylene is Prime Polypro E702MG manufactured by Prime Polymer Co., Ltd. It was used. Here, the base resin A is a mixture of the homotype polypropylene and the block type polypropylene at a ratio of 2:1, and the base resin B is a block type polypropylene, Prime Polypro E702MG manufactured by Prime Polymer Co., Ltd. only was used.

Test material 10 is a test material as a comparative example material using a polypropylene resin foam obtained by adding 2 parts of low-molecular-weight Kao surfactant-type antistatic agent ELASTOMASTER 320 to base resin A. Material 11 is a comparative example consisting of a laminated structure in which a polypropylene resin film in which a polymer type antistatic agent is added to the polypropylene resin of the base resin A at a high concentration is fused to the surface of the polypropylene resin foam by lamination extrusion. It is a test material as a material. Therefore, the test material 11 is Sumiceller ST (product name), which is a cushioning material using a resin foam with a laminated structure in which a film containing a polymer type antistatic agent is laminated on the surface manufactured by Sumika Plastics Co., Ltd. Although used, the resin foam as the support does not contain an antistatic agent.

(Tensile strength, open cell ratio)
Table 1 shows the test results. The base resin A is a hard foam material, and the base resin B is a soft foam material. Direction: 6.8 to 7.6 MPa, TD direction: 4.9 to 5.5 MPa, and the open cell rate is 10.7 to 12.4%. The tensile strength in the MD direction is 7.2 MPa in the MD direction, 5.4 MPa in the TD direction, and the open cell rate is 12.4%. It was 8.6 MPa, 5.6 MPa in the TD direction, and the open cell ratio was 11.8%. The tensile strength of the base resin B of the test material 4 was 5.5 MPa in the MD direction and 3.4 MPa in the TD direction, and the open cell ratio was 58.4%. Here, the values of the above tensile strength and open cell ratio were within a range in which both the test material and the comparative material had no problem as a transport container, a partition material for a transport container, or a cushioning material for packing.

(Surface resistivity of resin foam surface)
As can be seen from Table 1, the surface resistivity of test materials 1 to 9 containing the BN type charge-transfer type antistatic agent 7 days after production was 0.1 to 2.0% when the antistatic agent content was 0.1 to 2.0. 1.64 to 5.60×10 ¹¹ including the type of base resin of the masterbatch in the range of 0 parts by mass, and the surface resistivity one month after production is 1.48 to 2.97×10 ¹¹ Although there are individual differences in surface resistivity between materials, it is less than 10 ¹² in any case.
On the other hand, the test material 10 containing a surfactant-type antistatic agent, which is a comparative material, had a surface resistivity of 4.15 × 10 ¹¹ 7 days after production, which is included in the surface resistivity range of the present invention. However, the surface resistivity one month after production was 3.69×10 ¹¹ , which is higher than the surface resistivity of the present invention, and is considered to be at approximately the same level as a whole. In addition, the surface resistivity of the surface of the test material 11, which is a laminated structure material made of a polymer antistatic agent, was 3.85 × 10 ¹¹ 7 days after production, which is the surface resistivity range of the present invention. However, the surface resistivity one month after production is 3.17×10 ¹¹ , which is higher than the surface resistivity of the present invention, and is considered to be at approximately the same level as a whole.

When comparing Test Material 1 and Test Material 10 containing two parts each of a BN type charge transfer antistatic agent and a low molecular weight antistatic agent, Test Material 1 was superior to Test Material 10. In addition, the surface resistivity of the test material 11, which is a laminated structure material made of a polymer-type antistatic agent, is unknown, but the polymer-type antistatic agent is usually added from the present invention, although the detailed content of the antistatic agent is unknown. Despite being considered to contain a large amount, it was inferior to the present invention.

(Surface resistivity of sliced surface of resin foam)
For the surface resistivity of the sliced surface, the sliced surface was obtained by cutting not at the center of the thickness of the product, but at a position 1/4 from the surface in the thickness direction of the resin foam in consideration of wear and damage of the product. In Table 1, the sliced surface obtained by cutting the foamed surface of 1/4 thickness from the surface of the resin foam is the sliced surface of test materials 1 to 9 containing the BN type charge transfer type antistatic agent of Example 1. The surface resistivity of is 1.48 to 2.56×10 ¹² seven days after production and 3.34 to 5.13×10 ¹¹ one month after production, which is less than 10 ¹² . , the low-molecular-weight surfactant-type antistatic agent was 8.24×10 ¹⁴ 7 days after production, and 2.75×10 ¹⁴ even 1 month after production, and the polymer-type antistatic agent was 8.24×10 14 7 days after production. 8.26×10 ¹⁴ and 2.72×10 ¹⁴ even one month after production, both of which exhibit surface resistivities in the order of 10 ¹⁴ .
Therefore, test materials 1 to 9 of the present invention, regardless of the content of the BN type charge transfer type antistatic agent and the type of the base resin of the masterbatch, are low-molecular surfactant antistatic agents Compared to test materials 10 and 11 containing a polymer type antistatic agent, the surface resistivity of the sliced surface tends to decrease significantly. The reason for this is, for example, the difference in charge-removing mechanism from that of the semipolar BN type charge-transfer antistatic agent with other materials, and the uniformity of the BN-type charge-transfer antistatic agent on the cell wall surface surrounding the air bubbles on the slice surface. It is considered that this is obtained as a result of a structure in which the particles are dispersed at a high density in the On the other hand, in the case of the test material 10 containing a surfactant-type antistatic agent, or in the test in which the sliced surface of the laminated structure using a polymer-type antistatic agent is a foamed layer of a resin foam that does not contain an antistatic agent. This is considered to be because such an effect cannot be obtained in the case of the material 11.

(Electrification half-life of resin foam surface)
Here, looking at the measurement results of the charging half-life of each test material, the charging half-life of the polypropylene resin foam containing the BN type charge transfer type antistatic agent of test materials 1 to 9 is 0.10 sec. While below, the charge half-life of the polypropylene resin foam containing the surfactant type antistatic agent of Test Material 10 is 0.12 sec, and the polypropylene resin containing the polymer type antistatic agent of Test Material 11 The charging half-life of the foam is 0.74 sec. In any case, the charging half-life of the polypropylene resin foam containing the BN type charge transfer type antistatic agent is smaller than the charging half-life of the comparative example materials of test materials 10 and 11. It is considered that the N-type charge-transfer type antistatic agent has a more uniform and fine dispersion of the antistatic agent than the comparative example materials of test materials 10 and 11 containing other antistatic agents.

(Evaluation results of surface quality and foamability)
The surface quality was evaluated by visual observation, and there was no problem with the surface quality of the resin foam surfaces of test materials 1 to 7, and all of them were evaluated as "⊚". The surface of test material 8 is slightly inferior in uniformity of the surface of the resin foam, but there is no problem as a product and it is evaluated as "○". It became the failure evaluation of "x". In addition, test material 10 and test material 11, which are comparative examples, had no problem in surface quality, and both were evaluated as "⊚".
The foaming state of test materials 1 to 11 showed almost the same tendency as the surface state, but except for test material 9, the foaming states of test materials 1 to 8 and test materials 10 and 11 were all good. In contrast, only test material 9 was evaluated as "X" due to uneven bubbles and poor foaming state, and it was considered that this foaming state was reflected in the surface quality.

In addition, it is generally considered that when the resin component of the masterbatch and the resin component of the base resin are the same, the compatibility between the resins is excellent and the dispersibility is also excellent, but the test results in the present invention are different. . As for the reason for this, since the product of the present invention is a foamed product, it is necessary to consider not only the compatibility of the masterbatch addition but also the effect on the foamability.
Therefore, according to the test results of the test material when polypropylene is used instead of low-density polyethylene as the resin component constituting the masterbatch of the BN type charge transfer type antistatic agent of test material 9, the masterbatch is constructed. When polypropylene is used as the resin, the melting point of the resin constituting the masterbatch is high and it is difficult for the masterbatch to melt into the base resin. As a result, the foaming state became non-uniform, causing inhibition of foaming, and as a result, the surface quality of the polypropylene resin foam deteriorated. In addition, when high-density polyethylene is used as the resin constituting the masterbatch of test material 8, the surface resistivity and resin foaming are higher than when low-density polyethylene is used, although not as much as when polypropylene is used. The surface quality of the body was slightly lower, with both surface resistivity and surface quality falling short of those of low density polyethylene.

On the other hand, when the resin constituting the masterbatch containing the BN type charge-transfer type antistatic agent is low-density polyethylene or high-density polyethylene, the resin constituting the masterbatch is not polypropylene resin, but low-density polyethylene or high-density polyethylene. Since the melting point of density polyethylene is low, during the melt-kneading process between the base resin of the resin foam and the masterbatch in the extrusion foaming process, the low-density polyethylene and high-density polyethylene are completely melted. Compared with the case of using it as a base resin for the batch, it is considered to have less influence on the foaming process and to have the effect of improving the dispersibility of the masterbatch. It is considered that this can also be estimated from the comparison of the charging half-life of test materials 3, 8 and 9.

If the melting point of polypropylene, which is the base resin of the masterbatch, is the same as that of the base resin A of the foam, the melting point of the base resin A is about 167°C, and the melting point of the low-density polyethylene is about 107°C. Since the melting point of high-density polyethylene is about 131° C., and the melting point of low-density polyethylene is low, the dispersibility of the BN type charge transfer type antistatic agent in polypropylene resin foam is high when the base resin of the masterbatch is high. It is thought that dispersibility is superior to that of high-density polyethylene as compared to the case of high-density polyethylene as the base resin of the masterbatch, and there is also a difference in the neutralization mechanism of the semi-conductive BN type electrolytic transfer type antistatic agent. Then, bubbles are likely to occur on the cell wall surface at the interface between the BN type electrolytically transferable antistatic agent and the base resin of the resin foam, polypropylene, so that the surface resistivity of the sliced surface is lower than that of other materials in the comparative example. It was considered that the value closest to the surface of the foam was shown compared with the case of .

(Antibacterial property of resin foam)
In addition, Table 1 shows the antibacterial properties after 10 ⁶ dilution in accordance with JISZ 2801 on the foam surface of each test material of test materials 1 to 9, 10, and 11, and the foam surface of each test material. The results of measuring the number of colonies are shown. According to this, the number of colonies when the BN type charge transfer type antistatic agent of test materials 1 to 9 was used was 20 to 65, while the polymer type antistatic agent of test material 11 was used. The number of colonies was 195 in the case of the resin foam, and from the results of the antibacterial test, the number of colonies was higher when the BN type charge-transfer type antistatic agent was used than when the polymer type antistatic agent was used. It is considered that the number is small and the antibacterial property is excellent. In addition, the number of colonies when using the low-molecular-weight surfactant-type antistatic agent of test material 10 is 20, and when using the low-molecular-weight surfactant-type antistatic agent of test material 10, B- It is considered that the use of a low-molecular-weight surfactant-type antistatic agent is slightly superior to the case of using an N-type charge-transfer antistatic agent.

That is, the BN type charge transfer type antistatic agent according to the present invention exhibits antibacterial properties similar to those of surfactants, but does not cause the problem of bleeding out like surfactants, so it can be used as a continuous antistatic agent. It has the characteristics of having performance. Such performance is based on the findings of the present inventors, and a polypropylene resin foam product using this is constructed as having unique and novel properties conceptually.

(Comprehensive evaluation of the test material of Example 1)
As described above, from the results of Example 1, the resin foam containing the BN type charge transfer antistatic agent not only has antistatic performance on the surface of the resin foam, but also has antistatic properties on the sliced surface of the resin foam. It is also excellent in antistatic performance, and when compared with a polymer type antistatic agent having a similar sustained antistatic effect, such antistatic performance on the slice surface is better than that obtained by using a polymer type antistatic agent. In the case of test material 11, this was not recognized due to structural reasons such as the laminated structure consisting of a film containing an antistatic agent only on the surface.

Furthermore, from the antibacterial test, compared to the resin foam containing the polymer type antistatic agent,
It was confirmed that the resin foam containing the BN type charge transfer antistatic agent has excellent antibacterial properties. In addition, the resin foam containing the polymer type antistatic agent has the same surface resistivity as the resin foam containing the BN type charge transfer type antistatic agent, but the charge half-life is BN type. significantly higher than resin foams containing charge transfer antistatic agents. Such a difference in charge half-life is due to elimination of neutralization by static electricity between the polymer type antistatic agent and the BN type charge transfer type antistatic agent, as well as hole transport and electron diffusion inside the resin. In the case of a polymer type antistatic agent, the dispersal state of the antistatic agent is worse than that of the resin foam containing the BN type charge transfer type antistatic agent. It is presumed that this is due to the difference in the dispersion state of the inhibitor.

The result that the surface resistivity of the sliced surface of the resin foam containing the BN type charge-transfer type antistatic agent as described above is excellent is assumed to be used as a transport container for electronic parts and a partition material for these. In addition, good antistatic effects can be obtained even when the surface of these members deteriorates due to vibration or abrasion during transportation, and the foam layer is exposed on the surface, or when the product comes into contact with the cut end surface of the partition material. Therefore, it can be suitably used for returnable applications. In addition, compared to resin foams containing polymer-type antistatic agents, it has excellent antibacterial properties, so it is considered to be excellent in antibacterial and antifungal properties in transportation containers. It is considered that even in a high humidity environment, it is difficult for mold and fungi to propagate.

<Example 2>
In Example 2, Table 2 shows the test results of test material 12 to test material 21 when metal phthalocyanine pigments and other pigments were added to test material 3 of example 1 in predetermined ranges. Test material 12 to test material 15 are obtained by adding a Cu phthalocyanine pigment by changing the content in the range of 4.0 to 0.5 parts by mass. Test materials 17 to 19 are test materials obtained by adding 2 parts by mass of Fe phthalocyanine pigment, Co phthalocyanine pigment and Ni phthalocyanine pigment to Test material 3 of Example 1, respectively. The test material 20 is a material obtained by adding 2.0 parts by mass of titanium oxide to the test material 3, and the test material 21 is similarly obtained by adding 2.0 parts by mass of iron oxide to the test material 3.
In the present invention, the pigment is basically added by the direct blend method. Masterbatch: pigment masterbatch in which the composition ratio of low-density polyethylene and pigment is 2: 1). A direct blend. The test material 16 and the test material 14 containing the same amount of Cu phthalocyanine pigment can be compared.

The Cu, Fe, and Co phthalocyanines used in Example 2 were obtained from Tokyo Chemical Industry Co., Ltd., Ni phthalocyanine was obtained from Fuji Photo Wako Pure Chemical Industries, Ltd., and titanium oxide was obtained from Ishihara Sangyo Co., Ltd. , iron oxide manufactured by Dainichi Seika Kogyo Co., Ltd. was used. In the masterbatch of test material 16, low-density polyethylene was used as the base resin, and the mixing ratio of low-density polyethylene and Cu phthalocyanine was 2:1.

Here, the surface resistivity of the test material surface was measured for all the test materials from test material 12 to test material 21 in Table 2. Only test materials 13, 14, and 16 were measured on the sliced surface obtained by cutting the foamed surface with a thickness of 1/4 from the surface of the resin foam in the same manner as in the case. As for test material 9, surface resistivity measurement was stopped because the surface of test material became uneven and the surface state became unstable, and stable contact with the main electrode and the ring electrode could not be obtained. Here, test material 14 and test material 16 are materials with the same composition to which 2 parts by mass of Cu phthalocyanine pigment are added, but the pigment addition method is the direct blend method (DB) and the masterbatch method (MB). Only different.

(Various test results of test materials)
Since the test material in Example 2 contains a predetermined pigment in the test material 3 of Example 1, the tensile strength of the test material, the open cell rate, the surface resistivity of the resin foam surface, the charge Almost the same results as in Example 1 were obtained for the damping rate, the surface quality of the resin foam, and the foamability.
Specifically, the surface resistivity of the surface of the test material 3 was 2.07×10 ¹¹ seven days after production and 1.88×10 ¹¹ one month after production. The surface resistivity on the surface when a predetermined amount of pigment of test material 22 was added from 13 to 22 was 2.03 to 2.18×10 ¹¹ seven days after production, and 1.84 to 2.04× one month after production. At 10 ¹¹ , with Test Material 3 as a reference, the surface resistivity is in the range of ± about 10% of the surface resistivity of Test Material 3. In addition, the surface resistivity of the sliced surfaces of the test materials 13, 14, and 16 is within a range of about ±10% of the surface resistivity of the sliced surface of the test material 3 when the test material 3 is used as a reference. It is the same level as test material 3. On the other hand, the surface resistivity of the sliced surface of the comparative example material is on the order of 10 ¹⁴ , and the test materials 13, 14 and 16 of the present invention have much lower values than the test materials 10 and 11 of the comparative example. showing. For this reason, other pigment-added test materials are considered to exhibit similar tendencies, and therefore the surface resistivities of other test materials were not measured.
In addition, in order to evaluate the effect of the addition method of the pigment on the various characteristics of the test material, the test material 14 and the test material 16 were added with 1 part by mass of Cu phthalocyanine by direct blending and masterbatch addition. However, no significant difference was found between the direct blend and the masterbatch addition.
Test material 12 to test material 21 described in Example 2 have tensile strength, open cell ratio, surface resistivity in a predetermined number of days after production, and charge half-life, since the pigment is stable in the extrusion foaming process. Although there are some differences due to the difference in , there is no big difference that would cause a practical problem in mechanical properties, open cell ratio, etc., and it is said that it has roughly the same performance as test materials 1 to 9 in Example 1. Conceivable.

(Antibacterial effect by pigment of test material)
When comparing the results of the antibacterial test on the foam surface of the test material containing the metal phthalocyanine pigment of test material 12 to test material 19 and the foam surface of test material 3, the number of colonies in test material 3 is 37, In the case of test material 12 to test material 19, the number of colonies showed a value of zero or 5 or less. It was found that the resin foam to which the metal phthalocyanine pigments were added in this way had a significantly reduced number of colonies compared to the material to which these pigments were not added, showing an antibacterial effect. The test material 20 containing titanium oxide and the test material 21 containing iron oxide have a small number of colonies of 20, but the antibacterial properties are improved by containing the metal compound pigment compared to those without pigment addition. However, the effect is not so remarkable as compared with the case of metal phthalocyanine.

Here, the reason why the resin foam to which the metal phthalocyanine pigment is added exhibits antibacterial properties is that the metal part forming the phthalocyanine structure of the pigment having the metal phthalocyanine structure is typically Cu, but Fe, Fe, In either case of Ni or Co, since the metal phthalocyanine structure has an oxidizing action, it is thought that it has antibacterial and antifungal properties by inhibiting either the formation or proliferation of fungi, metabolism, or cell membranes. be done.

In the present invention, only the antibacterial test was performed, and the antifungal test was not performed. BN-type charge-transfer antistatic agents and metal phthalocyanines are thought to possess not only antibacterial but also antifungal properties because they are multicellular eukaryotes that evolved from .

<Example 3>
Further, as Example 3, in order to evaluate the antistatic performance after a long period of time for the test material 3, test material 10, and test material 11 described in Example 1, after holding for 35 days in a constant temperature bath at 60 ° C. , the surface resistivity was evaluated by an accelerated test for measuring the surface resistivity of the surface layer of these test materials. Since it can be considered that Arrhenius' 10 ° C. double rule can be applied to the holding time of this accelerated test, if the 60 ° C. holding time is converted to holding at room temperature based on this, the holding time at 20 ° C. room temperature conversion corresponds to about 1.5 years.

As a result, the surface resistivity of the material containing 2 parts by mass of the BN type charge transfer type antistatic agent of test material 3 was 1.60 × 10 ¹⁰ , and the polymer type antistatic agent of test material 11 was abundant. The surface ^resistivity of the laminate type ^containing and the surface resistivity of test material 10 was remarkably higher than that of test material 3 and test material 11. This is because the test materials using the long-lasting antistatic agents of test material 3 and test material 11 have a long-lasting effect of the antistatic agent, so the surface in the accelerated test corresponding to the test period of one and a half years The resistivity was less than 10 ¹³ , but the test material 10 containing the surfactant type antistatic agent bleed out during the retention of the antistatic agent at 60 ° C. for 35 days, and the surface of the test material It is considered that the surface resistivity was remarkably high because it disappeared from the surface.

(Overall summary of test results)
Here, from the results in Table 1, all the test materials containing the BN type charge transfer type antistatic agent of the present invention have a surface resistivity of 10 ¹² , which is 10 ¹³ or less on the sliced surface. On the other hand, both the test material 10 containing a low-molecular-weight surfactant-type antistatic agent and the laminated-type test material 11 containing a polymer-type antistatic agent have a surface resistivity of 10 ¹⁴ on the sliced surface. has become more than

Furthermore, the test material containing a low-molecular-weight antistatic agent was compared to the test material of the present invention, and the surface resistivity measurement test results after holding in a constant temperature bath at 60 ° C. for 35 days and Table 1 without acceleration test , From the measurement results of the surface resistivity of the sliced surface in Table 2, judging the long-term usability of the product of the present invention, the returnable transport container having persistent antistatic performance in the present invention or the partition material of the transport container It is a material that is not suitable as a cushioning material for packaging, and in the case of a polymer type antistatic agent, the long-term usability is almost the same as the product of the present invention based on the evaluation of surface resistivity by an accelerated test. The surface resistivity of the sliced surface was inferior to that of the product of the present invention, and the antibacterial and antifungal properties were also inferior to those of the present invention.

In addition, in comparison with polymer type antistatic agents, the surface resistivity of the material surface is considered to be almost the same except for the surface resistivity of the sliced surface and the antibacterial and antifungal properties. There is a large difference in content. Generally, the polymer type antistatic agent is contained in a content ratio of 5 parts by mass or more to about 10 parts by mass with respect to the base resin, but in the case of the BN type charge transfer type antistatic agent of the present invention, It is considered that a content in the range of 0.1 to 2.0 parts by mass has the same effect. The reason for this is the difference in the dispersion state of the antistatic agent due to the master batch of the BN type charge transfer type antistatic agent and the low density polyethylene, and the difference in the charge disappearance mechanism of the BN type charge transfer type antistatic agent. This is considered to be due to

In the present invention, from the results of Example 2 already described, it is considered that the antibacterial and antifungal effects of the pigment are superimposed on the antibacterial and antifungal effects of the BN type charge-transfer antistatic agent. was taken. The reason for the antibacterial and antifungal effects of the BN type charge transfer antistatic agent is unknown, but the antibacterial and antifungal effects of the metal phthalocyanine pigments are due to the oxidation effect of the metal phthalocyanine pigments on the metabolism of fungi and molds and the cell membranes. This was thought to be due to an inhibitory effect that inhibited either the generation or proliferation of

Here, the reason why the antibacterial property was evaluated only on the surface of the foam and not the sliced surface was that the effect of the air layer of the surface bubbles was not as remarkable as the surface resistivity, and the antibacterial property of the material composition was not affected. This is because at least substantially the same effect can be expected for the skin layer on the surface of the foam and the sliced surface. The reason for this is that the apparent cross-sectional area of the slice surface is larger than that of the skin layer without air bubbles, and the effective surface area is increased due to the formation of microscopic irregularities on the surface by the air bubbles. Three-dimensional deformation during the foaming process of the BN type charge-transfer antistatic agent by substantially increasing the surface area of the mobile antistatic agent and using polyethylene resin (mainly low-density polyethylene resin) in the masterbatch. This is because at least approximately the same effect can be expected on the surface and the sliced surface because the effect of exposing and dispersing the bubbles on the surface of the cell wall can also be expected. Therefore, for confirmation, an antibacterial test was performed on the sliced surface (1/4 surface of the sheet thickness) of test material 3, and the number of colonies on the sliced surface was 34 compared to 37 colonies on the surface of the foam. , it was confirmed that the antibacterial properties of the sliced surface were almost the same as those of the foam surface.

According to the present invention, a polypropylene resin foam containing a polyethylene resin and a BN type charge-transfer type antistatic agent as a sustained-type antistatic agent in a predetermined range and having excellent antistatic performance on the foam surface and sliced surface is used. A transport container, a partition material for a transport container, or a cushioning material for packaging having a long-lasting antistatic performance was obtained. Transportation containers having sustained antistatic performance using these polypropylene resin foams, partitioning materials for transportation containers, and cushioning materials for packaging have not only antistatic effects but also antibacterial effects. Products using these resin foams are allowed to contain a pigment within a predetermined range. In addition to these effects, remarkable antibacterial and antifungal effects can be expected without impairing the long-lasting antistatic action of BN type charge-transfer antistatic agents. Therefore, these products can be used as returnable transportation containers, partitioning materials for transportation containers, or cushioning materials for packing, while having antistatic performance that lasts and antibacterial and antifungal properties.

Here, products using the polypropylene resin foam of the present invention can be produced using a masterbatch in which a polyethylene resin and a BN type charge-transfer type antistatic agent are combined in a predetermined ratio. , the present invention provides methods of making these products. Since the base resin is polypropylene resin, it is preferable that the BN type charge-transfer antistatic agent of the masterbatch uses a low-density polyethylene resin having a lower melting point than the polypropylene base resin during melt kneading. . As a result, in addition to the compatibility of the masterbatch, the dispersibility of the antistatic agent is improved, and by making it easier to generate air bubbles at the interface between the masterbatch and the base resin, on the slice surface, the cell wall surface surrounding the air bubbles It was considered that the dispersion of a large amount of the BN type charge-transfer type antistatic agent resulted in excellent antistatic performance and foamability.

Furthermore, the present invention provides a transport container or a transport container using a polypropylene resin foam produced by a method for producing a polypropylene resin foam for a transport container, a partition material for a transport container, or a cushioning material for packaging. It becomes possible to provide the use for antibacterial and antifungal applications of partition materials and cushioning materials for packaging.

Although the embodiments of the present invention have been described above, the technical scope of the present invention is not affected by the above-described embodiments. It is obvious that a person skilled in the art can correspond to various modifications or modifications within the scope of the technical idea described in the claims, and these are also within the technical scope of the present invention. be understood to belong to For example, it goes without saying that the embodiments described above can be combined with each other.

The present invention provides a transportation container, a partition member for a transportation container , or a cushioning material for packing, using a polypropylene resin foam having a continuous antistatic performance that is excellent in antistatic performance on the surface of the foam and the foam layer inside the foam. and the use of these transport containers , partition members for transport containers , or cushioning materials for packaging for antibacterial and antifungal purposes.

Plastics are characterized by high electrical insulation and are used in a wide range of fields. However, due to this property, it is easily electrified and easily generates static electricity. This results in unwanted troubles related to static electricity. The most typical example is the adhesion of dirt and dust to plastic products. In addition, when static electricity is the most serious problem, discharge may cause malfunction or destruction of ICs, memory chips, and the like in electronic equipment and OA equipment.

In order to prevent such a phenomenon, countermeasures are taken to prevent static electricity. It is believed that the accumulation of static electricity can be suppressed by setting the resistance to ^13Ω or less.

Methods for preventing static electricity include a method of surface-treating plastics and a method of kneading plastics with a substance that imparts electrical conductivity. For example, it is possible to apply or knead a surfactant on the surface of a plastic, and it is possible to obtain an effect even with a small amount of use. Moreover, in the case of a hydrophilic surfactant, the effect is exhibited by the surfactant absorbing moisture.

However, this method has a problem that the effect does not last if the antistatic agent on the surface is lost. Moreover, even when the surfactant is kneaded into the resin, there is a problem that the surface of the resin is contaminated by bleeding out of the surfactant, and the product to be packed is contaminated. Moreover, since the surfactant has low heat resistance, it may decompose during molding.

Conductive fillers such as carbon black and carbon fiber can be considered as additives that do not have such problems, but they require a large amount of compounding, blacken the molded product and limit its application, and impact resistance is poor. There is a problem of lowering In the case of this method, the surface specific resistance can be significantly reduced, but problems such as cost and coloring of the product remain.

On the other hand, polymeric antistatic agents that do not bleed out, that is, long-lasting antistatic agents have been studied. For example, polyethylene glycol-methacrylate copolymers, polyether ester amides, polyether ester imides, which generally have a structure in which conductive units such as polyethylene oxide (PEO) are incorporated into the polymer chain in blocks or at random, Polyethylene oxide hydrin copolymers and the like have been put to practical use.

In the case of such a polymer-type antistatic agent, there are problems such as the need to add a large amount and difficulty in controlling dispersion in the resin due to the difference in viscosity from the base resin. In order to reduce costs, laminated resin foams have been developed in which an antistatic film layer is laminated on the surface of a resin foam by co-extrusion in applications such as cushioning materials for packaging and partition members.

On the other hand, inorganic boron compounds are used in industrial fields such as medicine, glass, ceramics, metal welding, semiconductors, etc., but methyl ester, ethyl ester and amyl ester of boric acid are the first organic boron compounds. However, boron compounds with a BO bond have been made since then.

Boron is usually trivalent and forms a compound bonded on a plane, but since it has one more empty orbital, it has the property of forming a tetravalent and tetrahedral structure compound when there is an adjacent hydroxyl group. The compound is characterized by a characteristic semi-polar bond between boron (B) and adjacent hydroxyl groups (OH).

On the other hand, the BN complex, which is structurally designed to be compatible with non-polar resins, has a polar part (BN) while the main chain part is held as an anchor in the target resin matrix. Can be fixed to the surface. As an antistatic agent using such a BN complex, there is BN105 as a BN type charge transfer type antistatic agent.

On the other hand, polypropylene resin foam is used as a cushioning material for packaging, and it is particularly used as a packaging material for transporting electronic equipment parts. In addition to performance, mold and fungi cause deterioration of the insulating substrate, noise generation, short circuit, etc. due to the decrease in pitch of the wiring pattern on the wiring board and the increase in use under harsh conditions with high humidity. In order to prevent the generation of , antibacterial properties and antifungal properties have been required for substrate materials of wiring boards and electronic parts.

Along with this, not only substrate materials for wiring boards and electronic parts, but also transport packaging materials that come into contact with these parts are required to have not only antistatic performance but also antibacterial and antifungal properties.

Antibacterial agents are roughly classified into organic antibacterial agents and antifungal agents into organic antibacterial agents and inorganic antibacterial agents. Some organic antibacterial agents are naturally derived, and have stronger antibacterial activity and higher sterilization speed than inorganic antibacterial agents. On the other hand, inorganic antibacterial agents have weaker bactericidal activity than organic antibacterial agents, but are characterized by the fact that they are less likely to produce resistant bacteria and have high heat resistance. Any antimicrobial substance must be safe under the environment of use. These antibacterial and antifungal agents are thought to exert their antibacterial and antifungal effects by causing cell collapse, cell death, inhibition of protein synthesis, etc., or inhibition of cell growth. there is

Patent Literature 1 discloses a polyolefin resin foam sheet having an antistatic function that provides an antistatic effect regardless of humidity conditions in the air, and has flexibility and cushioning properties. This polyolefin resin sheet contains a polymeric antistatic agent on at least one side of the polyolefin resin foam layer at a rate of 5 to 50 parts by weight with respect to 100 parts by weight of the base resin, and has a basis weight of 0.1 to 20 g/m. A polyolefin-based resin foam sheet in which ^two polyolefin resin layers are laminated is described.

According to the present invention, since the basis weight of the polyolefin-based resin layer containing the polymeric antistatic agent is 0.1 to 20 g/m ² , the properties of the foam layer are light, flexible and flexible. A polyolefin-based resin foam sheet excellent in cushioning properties and appearance can be obtained. It is possible to provide a multi-layer foamed sheet that has antistatic properties and that does not cause migration of low-molecular-weight components into the package.
The present invention is a laminated foam structure in which a resin layer containing a large amount of a polymeric antistatic agent is laminated on the surface of a resin foam.

In Patent Document 2, polypropylene containing 10 to 25 parts by weight of a polymer type antistatic agent having a similar melt flow rate and melting point to 100 parts by weight of a polypropylene resin having a predetermined flow rate (MFR) and melting point A polypropylene-based resin foamed sheet obtained by extruding and foaming a resin composition, the foamed sheet has a density of 0.05 to 0.1 g/cm ³ , a thickness of 0.5 to 2 mm, and a number of cells in the thickness direction of 1 to 1. A method for producing a polypropylene-based resin foam sheet is described, which is characterized by having a density of 3 pieces/mm and a surface resistivity of less than 1×10 ¹³ (Ω/□).

The invention of Patent Document 2 is a polyolefin-based resin foam that has an extremely low possibility of contaminating the surface of a contacting partner when used as a packaging material, has an excellent appearance, and exhibits uniform antistatic properties over the entire surface. and a polyolefin resin foam. Since this invention uses a polymer-type antistatic agent, the content of the antistatic agent relative to the base resin is as large as 10 to 25 parts by mass.

Patent Document 3 discloses a polyolefin resin sheet formed of a polyolefin resin composition containing a base resin made of at least one of polyethylene resin and polypropylene resin and a polymer antistatic agent. It is disclosed that the polymeric antistatic agent contains both a polymeric antistatic agent and a polystyrene resin that are incompatible with the base resin.

In the polyolefin-based resin sheet of Patent Document 3, a polystyrene resin having low compatibility with polyethylene-based resin and polypropylene-based resin is added to form a resin sheet. It will form a dispersed phase with a “sea-island structure”. At that time, the polymer antistatic agent can be aggregated along the interface between the polystyrene resin particles and the matrix resin to improve the function of the polymer antistatic agent. In other words, the amount of the polymeric antistatic agent to be used is reduced to achieve antistatic properties. The present invention does not include a resin that is incompatible with the base resin, nor does it form a dispersed layer having a sea-island structure.

Patent Document 4 contains a polyethylene resin, a polymer antistatic agent, an anionic surfactant, and a nonionic surfactant, and the polymer type electrostatic charge is added to 100 parts by mass of the polyethylene resin. 5 to 15 parts by mass of an inhibitor, 0.1 to 5 parts by mass of an alkylsulfonate surfactant as the anionic surfactant, and 0 part by mass of a polyoxyalkylene surfactant as the nonionic surfactant. 1 to 0.5 parts by mass, and the mass ratio of the anionic surfactant to the nonionic surfactant is 1 to 10 times.

According to this invention, the foreign matter adhering to the glass of the transportation container is composed of stearic acid-based compounds with relatively high lipophilicity, and other sebum, fibers, resin fine particles, and the like. On the other hand, it is described that the combined use of an anionic surfactant and a nonionic surfactant makes it possible to remove foreign matters adhering to the glass by washing with water. This invention is an invention that removes foreign substances by using a combination of a high-molecular-weight antistatic agent and a low-molecular-weight surfactant.

In Patent Document 5, component (A): an inorganic chemical containing a transition metal. Component (D): Surfactant and component (B), a surfactant having an antibacterial or antifungal effect containing a predetermined amount of two kinds of organic solvents with different boiling points as component (C), and a piezo-type spraying device using the same Disclosed is a space treatment agent.

The component (D) disclosed in this document contains either a cationic surfactant, an amphoteric surfactant or a semipolar surfactant. includes. This invention is a piezo-type spraying device in which an inorganic agent containing a transition metal and, if necessary, a cationic surfactant, an amphoteric surfactant and an amine oxide type surfactant as a semipolar surfactant are dispersed in a solvent. It is used as a space treatment agent.

Patent Literature 6 discloses an anti-static sheet that can utilize superior antibacterial and antifungal properties without using an antistatic agent such as a surfactant or carbon black. In addition, the antistatic antibacterial curtain material of Patent Document 6 uses a fabric as a base material, and in a flexible laminate having at least one antistatic resin layer provided on this base material, the antistatic resin layer is Contains a liquid ester compound having one or more ether bonds in the molecule and a chelate complex (metal ligand), and if necessary, has an area occupation ratio of at least 20% with respect to the surface of the antistatic resin layer A coating film layer having is provided. In the antistatic sheet of the present invention, the antistatic resin layer has antibacterial and antifungal properties, and the antistatic layer contains a liquid ester compound having an ether bond and a chelate complex.

The antistatic resin composition of Patent Document 7 comprises the following components (1) and (2), wherein component (1) is a propylene copolymer consisting of (A) and/or (B) below. (A) a ratio of 0.5 to 4.0% by weight of ethylene, 66.0 to 98.5% by weight of propylene, and 1.0 to 30.0% by weight of α-olefin having 4 to 12 carbon atoms (the A propylene random copolymer obtained by supplying the total amount of three components to a polymerization system.
(B) A propylene random copolymer obtained by supplying 2.5 to 10.0% by weight of ethylene and 90.0 to 97.5% by weight of propylene to a polymerization system (based on the total amount of the two components). is.

Furthermore, component (2): one or more semipolar organic boron polymer compounds represented by a specific general formula, and one tertiary amine having a total of 5 to 82 carbon atoms and having at least one hydroxyl group. Propylene-based copolymers are disclosed comprising a species or two or more species and a polymeric charge-transfer conjugate that is the reaction product of a ratio of one boron atom to one basic nitrogen atom.

Patent Document 7 describes a reaction between a specific propylene copolymer, an organic boron polymer compound in which boron atoms are regularly incorporated in the molecule while maintaining a semipolar bond structure, and a hydroxyalkylamine. By combining the polymer charge-transfer type binder, the chargeability of the propylene copolymer is removed, and the charging tube generated instantaneously by contact, friction, application of an external voltage, etc. quickly and completely leaks. It is described that, unlike the above-mentioned antistatic agents, it is possible to produce non-static products that are durable and stable. This document is a propylene-based copolymer containing an α-olefin containing a BN type charge transfer antistatic agent.

Since the invention of Patent Document 1 is a laminated resin foam, it is necessary to have a laminated structure, the structure is complicated, and there is a problem that antistatic performance cannot be imparted to the foam layer such as the sliced surface and the cut surface in the thickness direction. There is In the case of the invention of Patent Document 2, since a polymeric antistatic agent is used, there is a problem that the content of the antistatic agent to the base resin is as large as 10 to 25 parts by mass.

In the invention of Patent Document 3, the antistatic agent contains a resin incompatible with the base resin and forms a dispersed layer having a sea-island structure. Furthermore, it does not have a sea-island structure. The invention of Patent Document 4 is an invention that removes foreign matter by using a combination of a high-molecular-weight antistatic agent and a low-molecular-weight surfactant, and does not use a BN type charge-transfer type antistatic agent. The invention of Patent Document 5 uses a semipolar amine oxide surfactant dispersed in a solvent. The N-type semipolar charge-transfer compound is not used as an antistatic agent.

The antistatic resin layer disclosed in the invention of Patent Document 6 has antibacterial and antifungal properties, but the antistatic layer does not use a BN type charge transfer type antistatic agent. Patent Document 7 is a propylene copolymer containing a BN type charge-transfer type antistatic agent and containing an α-olefin in addition to a polypropylene resin and a polyethylene resin. - It is a polypropylene resin foam containing an N-type charge-transfer antistatic agent. However, there is no description or suggestion regarding the distribution of the BN type charge-transfer type antistatic agent on the sliced surface of No. 2 or the antibacterial/spinning properties of the foam, and the effect thereof is also unknown.

Japanese Patent Application Laid-Open No. 2005-074771 Japanese Patent Application Laid-Open No. 2009-191195 JP 2011-162764 A JP 2014-136755 A JP 2017-119680 JP 2019-093624 A JP-A-01-230653

Returnable shipping containers for electronic parts , partitioning materials for shipping containers, and cushioning materials for packing are designed to be used repeatedly. Due to abrasion from the product during transportation, the surface layer of the resin foam may be worn and peeled off, exposing the foam layer. A transport container using a resin foam that exhibits an excellent antistatic effect on both the surface of the foam and the foam layer, and at the same time, has antibacterial and antifungal properties and has a long-lasting antistatic performance . There are no container dividers or packing cushions. For this reason, development of such transport containers , partition members for transport containers , cushioning materials for packing, and resin foams used therefor has been expected.

In the present invention, in order to solve the above problems, a BN type charge transfer type antistatic agent is used, and even if the content of the antistatic agent with respect to the base resin is as small as 2.0 parts by mass or less, the resin Providing and transporting transportation containers , partitioning members for transportation containers, or cushioning materials for packaging using resin foams both of which have sustained antistatic performance on the surface of the foam and on the surface and inside of the foam layer of the resin foam It is intended to be used for antibacterial and antifungal applications in containers, partitions of transport containers, and cushioning materials for packaging .

Furthermore, these transport containers , partition members for transport containers, and cushioning materials for packaging are also excellent in antibacterial or antifungal properties, and the resin foam used for these is a B—N type charge-transfer charging Using a masterbatch of polyethylene and a B —N type charge transfer type antistatic agent as an inhibitor, finely dispersing the B—N type charge transfer type antistatic agent inside the resin foam, and extruding and foaming. can be manufactured. In this case, it is presumed that it is particularly preferable to use LDPE as the low-density polyethylene for the constituent resin of the masterbatch.

The transport container, the partition member of the transport container, or the cushioning material for packaging of the present invention uses a polypropylene resin as a base resin , and 0.3 to 8 LDPE as a low-density polyethylene resin per 100 parts by mass of the polypropylene resin. A polypropylene extruded resin foam having sustained antistatic performance and excellent surface quality, containing 0.0 part by mass and further containing 0.1 to 2.0 parts by mass of a BN type charge-transfer type antistatic agent. consists of
Both the foam surface and the foam layer of the extruded resin foam are excellent in antistatic performance, and the outer surface of the extruded resin foam comprises a skin layer and a slice surface or a sheet cut surface. It is a transport container , a partition member of a transport container , or a cushioning material for packing,
The surface resistivity of the sliced surface, which is the foamed resin layer of the extruded polypropylene resin foam surface and the foamed resin layer measured in accordance with JISK6911, is higher than the surface resistivity of the skin layer of the foam surface, and the surface resistance of both Both ratios are 1.0×10 ¹³ Ω/□ or less ,
In addition to the antistatic effect based on the surface resistivity, the extruded resin foam has an antibacterial effect or an antifungal effect,
A polypropylene extruded resin foam sheet characterized in that it can be used for antibacterial or antifungal purposes based on the antibacterial or antifungal effect confirmed by the antibacterial test conducted with reference to JIS Z2801. Used and reusable transportation containers , partition members for transportation containers , or cushioning materials for packing.
In the transport container, the partition member of the transport container, or the cushioning material for packing, the surface resistivity of the foamed resin layer on the surface of the polypropylene resin foam and the sliced surface is 5.0 × 10 ¹² Ω/□ or less and 3.0. It is also possible to set it to ×10 ¹² Ω/□.
Here, the BN type charge transfer type antistatic agent can be in the range of 0.1 to 1.0 parts by weight or 0.1 to 0.8 parts by weight. The antistatic agent has a sufficient effect even when it is 1.0 parts by mass or less or 0.8 parts by mass or less.

In addition, the transport container, the partition member of the transport container, or the cushioning material for packing conforms to JIS K6911 of the skin layer on the surface of the extruded polypropylene resin foam and the foamed resin layer on the sliced surface at a thickness of 1/4 from the surface. A polypropylene extruded resin characterized in that the surface resistivity of the skin layer is 1.0×10 ¹² Ω/□ or less and the surface resistivity of the sliced surface is 5.0×10 ¹² Ω/□ or less, as measured in accordance with It is also possible to use the foam sheet as a transport container that can be used repeatedly, as a partition member for the transport container , or as a cushioning material for packing.
In addition, the transport container , the partition member of the transport container, or the cushioning material for packing is a transport container using a high-strength polypropylene resin foam having a tensile strength of 6.5 to 8.0 MPa in the MD direction . It can also be used as a container partition member or a packing cushioning material, and a transport container using a low-strength to high-strength polypropylene resin foam having a tensile strength in the MD direction of 5.0 to 8.0 MPa . It can also be used as a partition member for a container or a cushioning material for packing. The strength in the MD direction of the high-strength transport container , the partition member of the transport container , or the cushioning material for packaging is preferably 6.8 to 7.6 MPa, and the strength range from low strength to high strength is desirable. is 5.5 to 7.6 MPa.

The transportation container, the partitioning member of the transportation container, or the cushioning material for packaging is a reusable polypropylene extruded resin foam sheet characterized by having a charging half-life of 0.10 seconds or less in the surface layer. It may be a transport container, a partition member of the transport container, or a cushioning material for packing .

The polypropylene resin foam used for the transport container, the partition member of the transport container, or the cushioning material for packaging uses polypropylene resin as the base resin, and LDPE as the low-density polyethylene resin for 100 parts by mass of the polypropylene resin. 0.3 to 10 parts by mass, 0.1 to 2.0 parts by mass of a BN type charge-transfer type antistatic agent, and 0.1 part by mass of a pigment . Consists of a polypropylene extruded resin foam having a sustained antistatic performance in the range of 5 to 4.0 parts by mass and excellent surface quality,
Both the foam surface and the foam layer of the extruded resin foam are excellent in antistatic performance, and the outer surface of the extruded resin foam comprises a skin layer and a slice surface or a sheet cut surface. It is a transport container, a partition member of a transport container, or a cushioning material for packing,
The pigment is a metal phthalocyanine-based compound, and the metal phthalocyanine compound is any one of Cu, Co, Fe, and Ni metal phthalocyanine-based compounds,
The surface resistivity of the sliced surface, which is the foamed resin layer, measured according to JISK6911 of the extruded polypropylene resin foam surface and the foamed resin layer is higher than the surface resistivity of the skin layer of the foam surface, and the surface resistivity of both is higher than that of the skin layer of the foam surface. Both are 1.0×10 ¹³ Ω/□ or less,
In addition to the antistatic effect based on the surface resistivity, the extruded resin foam has an antibacterial effect or an antifungal effect,
A polypropylene-based extruded resin foam sheet characterized in that it can be used for antibacterial or antifungal purposes based on the antibacterial or antifungal effect confirmed by the antibacterial test conducted with reference to JIS Z2801. It may be a transport container that can be used repeatedly , a partition member for a transport container , or a cushioning material for packing.
Here, when the pigment is contained in the resin foam, if the pigment content is small, LDPE may be added together as a low-density polyethylene resin as a masterbatch of the polyethylene resin and the pigment.

The transport container, the partition member of the transport container, or the cushioning material for packing conforms to JISK6911 for the skin layer on the surface of the extruded polypropylene resin foam and the foamed resin layer on the sliced surface at a thickness of 1/4 from the surface. A polypropylene extruded resin foam sheet characterized by having a surface resistivity of 1.0×10 ¹² Ω/□ or less of a skin layer and a surface resistivity of 5.0×10 ¹² Ω/□ or less of a sliced surface measured by It may be a transport container that can be used repeatedly , a partition member for a transport container , or a cushioning material for packing.

The transportation container, the partitioning member of the transportation container, or the cushioning material for packaging is a reusable polypropylene extruded resin foam sheet characterized by having a charging half-life of 0.10 seconds or less in the surface layer. It may be a transport container , a partition member for a transport container , or a cushioning material for packing.

The antibacterial effect or antifungal effect confirmed by the antibacterial test conducted with reference to JIS Z2801 of the transport container, the partition member of the transport container, or the cushioning material for packaging is characterized by being substantially equivalent to that of the low-molecular antistatic agent. It may be a reusable transport container , a partition member for a transport container, or a cushioning material for packing, using a polypropylene extruded resin foam sheet.

The extruded polypropylene resin foam used for the transport container, the partition member of the transport container, or the cushioning material for packaging contains a flame retardant such as an antimony flame retardant, a hydroxide flame retardant, or a brominated flame retardant. It may be a reusable shipping container , a partitioning member for a shipping container, or a cushioning material for packing using an extruded polypropylene resin foam sheet characterized by containing in the range of 0 to 5.0 parts by mass.

In the second invention, for the transport container, the partition member of the transport container, or the cushioning material for packaging, the polypropylene resin is used as a base resin, and LDPE is used as a low-density polyethylene resin for 100 parts by mass of the polypropylene resin. 0.3 to 8.0 parts by mass of and further containing 0.1 to 2.0 parts by mass of a BN type charge transfer type antistatic agent in a range of 0.1 to 2.0 parts by mass. It is used for antibacterial and antifungal applications for reusable transport containers , partition members for transport containers, and cushioning materials for packaging using extruded polypropylene resin foam sheets composed of.
For the transport container, the partition member of the transport container, or the cushioning material for packaging, the polypropylene resin is used as the base resin, and 0.3 to 10 LDPE is added as a low-density polyethylene resin to 100 parts by mass of the polypropylene resin. A polypropylene extrusion resin having sustained antistatic performance, containing 0.1 to 2.0 parts by weight of a BN type charge-transfer type antistatic agent and 0.5 to 4.0 parts by weight of a pigment. It may also be used for reusable transport containers using extruded polypropylene resin foam sheets composed of foam, partition members for transport containers, or cushioning materials for packaging for antibacterial and antifungal purposes .

The transport container, the partition member of the transport container, or the cushioning material for packaging of the present invention is a master of LDPE as a low-density polyethylene resin of a BN type charge transfer type antistatic agent with respect to 100 parts by mass of polypropylene resin. Add 0.4 to 10 parts by mass or less of a masterbatch containing 1/4 or less of the BN type charge-transfer type antistatic agent relative to the total weight of the batch with respect to 100 parts by mass of the base polypropylene resin. , Melt-kneading, performing gas foaming during melt-kneading, containing 0.3 to 8.0 parts by mass of LDPE as a low-density polyethylene resin per 100 parts by mass of polypropylene resin, BN charge transfer Transport container by manufacturing polypropylene resin foam for transport container , partition member of transport container , or cushioning material for packing containing antistatic agent in the range of 0.1 to 2.0 parts by mass , a polypropylene resin foam for use as a partition member of a shipping container or a cushioning material for packaging.
The polypropylene resin foam contains 0.3 to 10 parts by mass of LDPE as the low-density polyethylene resin, and the pigment is a metal phthalocyanine compound of Cu, Co, Fe, and Ni as a pigment with respect to 100 parts by mass of the polypropylene resin. 0.5 to 4.0 parts by mass of any one of the pigments may be used in the same manner.

According to the present invention, a transport container and a partition member for a transport container using a polypropylene resin foam that has a continuous antistatic performance on the surface of the foam and a foam layer inside the foam and has excellent surface quality. Alternatively, it is possible to obtain a cushioning material for packaging and to use the transportation container , the partition member of the transportation container, or the cushioning material for packaging for antibacterial and antifungal purposes.
The product of the present invention not only has excellent antistatic performance, but also excellent antibacterial and antifungal properties. By adding a polar BN type charge transfer type antistatic agent in a small amount of 0.1 to 2.0 parts by mass or less to the resin foam, both the surface and the sliced surface of the resin foam are sufficiently treated. It becomes possible to obtain a sustained antistatic effect and an antibacterial/antifungal effect on the foam.

In addition, in the present invention, when producing the resin foam used for these products, an LDPE masterbatch obtained by mixing LDPE, which is a low-density polyethylene, and a semipolar B—N type charge transfer type antistatic agent, is used. This is realized based on the fact that a good foaming state and a good dispersion state of the antistatic agent can be obtained. Transportation containers, partition members and packing cushioning materials for transportation containers, manufacturing methods thereof, and enabling the use of these products for antibacterial and antifungal purposes, and at the same time reducing the amount of antistatic agents, Cost reduction can be realized . In particular, good antibacterial and antifungal effects can be obtained by adding a phthalocyanine pigment in addition to the BN type charge-transfer antistatic agent.

[Polypropylene resin foam]
The polypropylene resin foam for the transport container , the partition member of the transport container, or the cushioning material for packaging of the present invention is antistatic containing a polypropylene resin and a B—N type charge transfer type antistatic agent. Excellent polypropylene foam. That is, the polypropylene resin foam of the present invention is a foam sheet formed using a resin composition containing at least a polypropylene resin and a BN type charge-transfer type antistatic agent. In addition, the polypropylene resin foam of the present invention may contain a cell nucleating agent in order to stabilize foamability.

<Polypropylene resin>
The polypropylene resin used as a raw material for the polypropylene resin foam for the transport container , the partition member of the transport container, or the cushioning material for packaging of the present invention uses propylene as a monomer and uses a polypropylene resin obtained by polymerization in a conventional manner. be able to. In addition, the polypropylene resin used as the raw material can be used by appropriately blending homopolymers, block polymers, random polymers, etc. having various structures in order to adjust the performance of the polypropylene resin foam. For example, if the base resin contains a large amount of a homopolymer with high melt tension, the melt tension of the polypropylene resin is improved, the proportion of open cells in the polypropylene resin foam is reduced, and the proportion of closed cells is increased. , a high-strength polypropylene resin foam can be obtained.

Further, the tensile strength, elongation value, flexural strength, flexural modulus, tear strength, etc. in the tensile test of the polypropylene resin foam for the transport container , the partition member of the transport container, or the cushioning material for packaging of the present invention are , The selection and mixing ratio of polypropylene resins with various structures used as the raw materials, the amount of bubble nucleating agent added, the amount of carbon dioxide injected during melt kneading during extrusion, and the pressure adjustment during injection are controlled. becomes possible.

For example, the polypropylene resin used in the present invention is commercially available. As described above, in order to adjust the tensile strength, flexural strength, flexural modulus, tear strength, etc. in the tensile test of the polypropylene resin foam, it is also possible to adjust by blending the homopolymer and the block polymer. It is possible. In order to achieve the above mechanical properties of high strength and high rigidity, the content of the homopolymer should be increased and the foaming conditions should be controlled to increase the ratio of closed cells to open cells.

<BN type charge transfer type antistatic agent>
The BN type charge transfer antistatic agent is a BN complex structurally designed to be compatible with a non-polar resin, with the main chain part held as an anchor in the target resin matrix, Polar moieties (BN) are anchored to the surface. This antistatic agent is composed of an organic nitrogen compound that corresponds to the (−) charge and erases the N component and a B component (semipolar organic compound) that corresponds to the (+) charge and erases It is composed of a boron compound), and causes a charge transfer transition at the same time as static electricity is generated, and instantly converts to an ion pair structure.

In addition, the BN type charge transfer antistatic agent has a structure in which the (B) component and the (N) component are integrated and have three alkyl groups. If (-CH ₂ -) is present, it has the property of existing as fine particles stably dispersed inside by activating the Fadel-Waals force. In contrast, it is said that antistatic performance can be obtained by adding a small amount because of its excellent compatibility and dispersibility with polyolefin resins such as polyethylene and polypropylene.
The BN type charge transfer type antistatic agent is preferably a compound represented by the following general formula (1).

〔式中、Ｒ^１およびＲ^２はそれぞれ独立に炭素数１～２４のアルキル基を表す。Ｒ^３およびＲ^４はそれぞれ独立に水素原子または炭素数１～４のアルキル基を表す。Ｒ^５は炭素数１～１２のアルキレン基を表す。Ｒ^６は炭素数１～２４のアルキル基を表す。Ｒ^１～Ｒ^６はさらに発明の効果を奏する範囲で任意の置換基（ヒドロキシル基等）を有していてもよい。また、発明の効果を奏する範囲で、アルキレン鎖（ＣＨ_２）の一部が酸素原子（Ｏ）、カルボニル基（ＣＯ）、イミノ基（ＮＨ）に置き換わった構造を取っていてもよい。〕
Ｂ－Ｎタイプ電荷移動型帯電防止剤は、なかでも、下記式（２）で表される化合物であることが好ましい。

[In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 24 carbon atoms. R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R ⁵ represents an alkylene group having 1 to 12 carbon atoms. R ⁶ represents an alkyl group having 1 to 24 carbon atoms. R ¹ to R ⁶ may further have any substituent (hydroxyl group, etc.) within the scope of achieving the effects of the invention. In addition, a structure in which a part of the alkylene chain (CH ₂ ) is replaced with an oxygen atom (O), a carbonyl group (CO), or an imino group (NH) may be employed within the scope of the effects of the invention. ]
The BN type charge transfer type antistatic agent is preferably a compound represented by the following formula (2).

Antistatic agents using boron include donor-acceptor type molecular compound type antistatic agents, ion pair compound type antistatic agents by neutralization reaction, and hybrid type antistatic agents of semipolar organic boron compounds and electrolytes . In the present invention, BN105, a BN type charge transfer antistatic agent manufactured by Boron Laboratory Co., Ltd., was used as the donor-acceptor molecular compound type antistatic agent. . The reason why BN105 is used in the present invention is that it has excellent dispersibility in polyolefin resins such as polypropylene having methylene groups.
Here, BN105 is a 1:1 molecular compound composed of the nonionic compounds of the (B) component and the (N) component, which undergoes charge transfer transition when the charges of the (+) component and (-) are present, and the surface of the resin And it has the effect of eliminating static charges inside. Therefore, a transition reaction occurs in which protons are transferred from the donor B compound to the acceptor N compound. As a result, charges are neutralized and eliminated on the surface of the resin foam, and charges are removed by transport of holes by B and diffusion of electrons by N on the surface other than the surface. becomes possible.

As the content of the BN type charge transfer type antistatic agent, the amount of the BN type charge transfer type antistatic agent added to 100 parts by mass of the polypropylene resin is 0.1 to 2.0 parts by mass. It can be added within the range of 0.1 to 1.0 parts by mass, and a sufficient antistatic effect can be obtained. When aiming for a surface resistivity of 1.00×10 ¹³ Ω/□ or less, the above addition amount is sufficient.
Surprisingly, it was found that the BN type charge-transfer type antistatic agent exerts an antibacterial effect (see Table 1, test materials 1 to 10). There is no literature disclosing that the BN type charge transfer type antistatic agent exhibits an antibacterial effect, and the BN type charge transfer type antistatic agent is incorporated into a polypropylene foam to exhibit antibacterial properties and to demonstrate the effect. The "transportation container" or the "transportation container partitioning material" and "packing cushioning material" that are used are constructed based on the above findings and have philosophically new features. is.

<Master batch of BN type charge transfer antistatic agent>
In order to maximize the performance of the BN type charge transfer type antistatic agent, unlike the surfactant type low molecular weight antistatic agent, it does not involve bleeding out to the surface of the foam, It is important to control the state of dispersion of the BN type charge transfer antistatic agent.

As the BN type charge transfer type antistatic agent, a polypropylene resin is used in which a predetermined amount of a masterbatch in which a BN type charge transfer type antistatic agent is dispersed in a low density polyethylene (LDPE) resin is mixed with polypropylene. be able to. Here, as the above masterbatch, LDPE as a low-density polyethylene and a BN type charge-transfer antistatic agent are mixed, melt-extruded, and then cut to produce a masterbatch.

LDPE is used as the polyethylene resin used in the masterbatch. Considering the dispersibility of the agent, it is preferable that the mixing ratio of the B—N type charge-transfer type antistatic agent in the polyethylene resin is at least 3 times or more. More preferably, it is 4 times or more, or 5 times or more, and 7 times or less. In terms of the content ratio of the BN type charge transfer type antistatic agent to the total weight of the masterbatch of the BN type charge transfer type antistatic agent and the polyethylene resin, it is 1/8 or more and 1/4 or less. is preferred.

Here, the reason why the lower limit of the ratio of the resin component constituting the masterbatch is set to 3 times or more and 8 times or less is that a stable masterbatch with a uniform composition cannot be obtained if the resin component is small. When the mixing ratio of the resin component is high, the mixing amount of the resin to be mixed in the masterbatch with respect to the polypropylene resin of the base resin of the resin foam is large in order to obtain the same content of the BN type charge transfer type antistatic agent. As a result, the content of the resin component introduced from the masterbatch to the resin foam increases, which affects the strength and heat resistance of the polypropylene resin foam itself.

The masterbatch can be produced in-house, but commercially available polycol or the like can also be used. Here, the mixing ratio of LDPE as the low-density polyethylene resin of the masterbatch and the BN type charge-transfer type antistatic agent can be appropriately adjusted within the above range, but the preferable range is 3 times or more. twice or less (the ratio of the BN type charge transfer antistatic agent to the total weight of the masterbatch is in the range of 4:1 to 8:1) .

<Other resin components>
The base resin is a polypropylene resin, but if it is a small amount other than the polypropylene resin, LDPE as a low-density polyethylene resin as another resin component is 0.3 parts by mass to 8.0 parts per 100 parts by mass of the polypropylene resin. It may be contained within the range of parts by mass. For example, in order to uniformly disperse a BN type charge transfer antistatic agent in a polypropylene resin, it is desirable to prepare a masterbatch mixed with LDPE as a low density polyethylene resin.

Here, the reason why the content of LDPE as the polyethylene resin introduced from the antistatic agent masterbatch for the polypropylene resin is set to 8.0 parts by mass or less is that the content of LDPE as the polyethylene resin introduced from the masterbatch is If it increases, the mechanical properties such as tensile strength, flexural strength, flexural modulus, tear strength and heat resistance of the polypropylene resin foam will decrease. The upper limit is preferably 8.0 parts by mass, preferably 6.0 parts by mass or less, and particularly preferably 4.0 parts by mass or less. Here, considering the content of LDPE as a polyethylene resin introduced from a pigment masterbatch, which will be described later, the content of LDPE as a polyethylene resin is allowed up to 10 parts by mass in total. The lower limit of the content of LDPE as a polyethylene resin depends on the mixing ratio of the base resin of the masterbatch to 0.1 parts by mass, which is the lower limit of the BN type charge-transfer antistatic agent . From the viewpoint of suitably exhibiting the dispersion effect of Starbatch , the amount is preferably 0.3 parts by mass or more, particularly preferably 0.4 parts by mass or more, and particularly preferably 0.6 parts by mass or more.

Here, there is no particular problem if the mixing ratio of the masterbatch resin and the BN type charge transfer antistatic agent is in the range of 3: 1 to 7: 1, so in the present invention, the transport in the present invention 0.1 to 2.0 parts by mass of a resin foam or BN type charge transfer type antistatic agent as a material for use as a partition member of a container for storage , a transportation container , or a cushioning material for packaging, masterbatch Low density as the base resin of the BN type charge transfer type antistatic agent and the masterbatch within a range that does not inhibit the inclusion of 0.3 to 8.0 parts by mass of LDPE as a polyethylene resin as a base resin of As long as the LDPE, which is a polyethylene resin, satisfies the content range, the mixing ratio of the masterbatch is the same as the composition range of these BN type charge transfer type antistatic agents and the low density polyethylene resin as the base resin. There is no particular problem even if the above mixing ratio cannot be applied over the entire range of 3:1 to 7:1, which is the entire range of the composition range of LDPE , and the mixing ratio of the masterbatch should not exceed the above composition range. should be adjusted accordingly. Needless to say, this corresponds to a ratio of 4:1 to 8:1 of the BN type charge-transfer type antistatic agent to the total weight of the masterbatch.

<Bubble nucleating agent>
The polypropylene resin foam of the present invention contains a cell nucleating agent. This cell nucleating agent promotes the formation of cell nuclei when the resin is foamed in the sheet manufacturing process, and improves cell miniaturization and uniform dispersibility. The cell nucleating agent used in the present invention is not particularly limited, and for example, sodium bicarbonate, ammonium bicarbonate, sodium bicarbonate citric acid, azodicarbonamide, talc, etc. can be used as the cell nucleating agent.

In addition, the present invention is not limited to these, and can be widely applied to those commonly used in resin foaming. Here, the content of the cell nucleating agent may be about 0.5 to 2.0 parts by mass with respect to 100 parts by mass of the polypropylene resin, but usually about 1 part by mass is sufficient.

<Other additives>
(pigment)
The polypropylene resin foam of the present invention may contain additives such as pigments, heat resistance improvers, flame retardants, etc., as long as the effects of the present invention are not impaired. A pigment is used to color the polypropylene resin foam sheet. Mainly used pigments include white pigments, yellow pigments, blue pigments, green pigments, red pigments and black pigments.

Specific examples of these pigments include white pigments such as titanium oxide, white lead, and antimony oxide; yellow pigments such as yellow lead, zinc yellow, chrome yellow, cadmium yellow, and other inorganic yellow pigments; and blue pigments. organic metal pigments such as Cu phthalocyanine and Co phthalocyanine; green pigments such as phthalocyanine green (highly chlorinated Cu phthalocyanine); Red is used. Moreover, carbon black etc. can be used as a black pigment. In addition to the above, other phthalocyanine pigments include dark blue Ni phthalocyanine, dark purple, green, and black Fe phthalocyanine, and these phthalocyanine pigments may also be used.

Among the above pigments, titanium oxide (rutile type) or carbon black can be used as the heat resistance imparting member when heat resistance is to be imparted. This is because titanium oxide has high heat resistance and excellent heat reflectivity, and carbon black has high heat resistance and excellent thermal conductivity.

Further, when a pigment composed of an organic metal complex such as phthalocyanine blue or phthalocyanine green is used, antibacterial and antifungal properties can be expected. Although the reason for this has not been completely elucidated, phthalocyanine-based pigments such as Cu, Co, Ni, and Fe phthalocyanines have an oxidizing action, which contributes to the formation of cells of fungi and molds. It is presumed that by inhibiting metabolism, it exerts its antibacterial and antifungal effects.

It should be noted that the antibacterial effect of pigments has been unclear in the past, and it has been more unclear whether it functions in polypropylene resin foams. In particular, according to the present invention, in specific pigments such as phthalocyanine pigments, the long-lasting antistatic effect of the coexisting BN type charge-transfer antistatic agent is not impaired, while the foam is extremely It is a new finding of the present invention that a good antibacterial effect can be obtained.

Here, the content of these pigments is desirably in the range of 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the polypropylene resin. The reason why the upper limit of the content of the pigment is 4.0 parts by mass is that 4.0 parts by mass is sufficient to obtain the desired coloring state as a product when considering the intended use as a pigment. Because it is. The reason why the lower limit of the content is 0.5 parts by mass is that if the content is less than 0.5 parts, the coloring may be insufficient. Therefore, the preferred amount of the pigment to be added is 0.5 to 4.0 parts by mass, but considering the cost of the pigment, it is desirable to use the content in the range of 0.5 to 2.0 parts by mass. Further, even when titanium oxide, carbon black, or the like is used for improving heat resistance, the range of addition amounts of these faces is the same as described above. Here, the pigment is added in principle by direct blending, but when the amount of pigment added is small, masterbatch addition may be used.

(Flame retardants)
The transport container , the partition member of the transport container, or the cushioning material for packing is a polyolefin resin foam containing a flame retardant selected from antimony flame retardants, hydroxide flame retardants, and bromine flame retardants. may be In addition, when the said polypropylene resin foam contains a flame retardant, as for content of a flame retardant, 4.0 mass parts or less is desirable. If the content of the flame retardant is 4.0 parts by mass or less, there is no concern that foaming will be inhibited. This is because a certain degree of flame retardancy can be ensured if the amount of the flame retardant added is in the range of 1.0 to 4.0 parts by mass.

<Production of polypropylene foam sheet>
In an extruder with a cylinder diameter of 150 mm, a polypropylene resin (component (A)) and a masterbatch (B) containing a B—N charge transfer type antistatic agent component (preferably 0.4 to 8.0 parts by mass, based on material polypropylene resin 100 parts by mass) were added in a predetermined ratio and kneaded. Carbon dioxide gas is extruded from the center of the tip of a T-shaped foaming die with a width of 400 mm at a predetermined gas pressure and gas flow rate from the cylinder part in the middle of the extruder, and the kneaded material is passed between two sets of horizontally installed forming roll dies. let it pass. By adjusting the rolling rate in this manner, a polypropylene resin foam sheet having a predetermined thickness can be obtained. This polypropylene resin foam sheet can be produced at an extrusion temperature of 160 to 195° C. and by rolling in the MD direction with a forming roll die at a rolling rate of 20 to 90%. In addition, an air bubble nucleating agent, a pigment, or the like can be added at a predetermined ratio as necessary.

<Product thickness of resin foam>
The polypropylene foam of the present invention is sheet-like, and the thickness of the foam sheet is appropriately designed according to the purpose. For example, it can be a foam sheet with a thickness of 1.0 to 5.0 mm. The thickness of the foamed sheet having these thicknesses can be appropriately adjusted by appropriately setting the rolling rate for extrusion and subsequent rolling of the sheet. As will be described later, in the examples of the present invention, the sheet thickness of the foam was standardized at 3.0 mm.

<Structure of resin foam>
The polypropylene resin foam used in the present invention preferably has an expansion ratio of 1.5 to 4 times. Predetermined strength and elongation values can be obtained by setting the foaming ratio to 1.5 to 4 times. This expansion ratio is more preferably 1.5 to 3.3 times. Here, in the case of a resin foam obtained by rolling a polypropylene resin foam with a low expansion ratio using a forming roll die, as in the present application, if the expansion ratio is almost the same, the tensile strength and elongation value are different depending on the type of base resin. In addition to this, the orientation of the resin also has an effect.

Further, the polypropylene resin foam used in the present invention is adjusted to have an open cell rate of 10 to 60%. By adjusting the open cell ratio to 10 to 60%, it is possible to appropriately adjust the tensile strength, elongation value, flexural modulus, flexural strength, compressive strength, etc. of the polypropylene resin foam to predetermined values. Become. Therefore, in order to avoid crushing of the resin foam as much as possible, and to set a predetermined compressive strength higher, or to give a predetermined tensile strength, bending strength, or a predetermined bending elastic modulus, polypropylene resin foam It is preferable that the open cell ratio of is small to a certain extent and that the number of closed cells is large. Here, the open cell ratio can be adjusted by appropriately adjusting the strain hardening property at high temperatures, the melt tension, the amount of gas during extrusion foaming, and the like.
Here, a high-strength material can be obtained when the open-cell rate is around 10%, and a low-strength material can be obtained when the open-cell rate is around 60%. The open cell ratio can be adjusted by adjusting the melt tension of the base resin forming the resin foam.

The cells of the polypropylene resin foam of the present invention are stretched in the MD direction by rolling, and are reduced in diameter in the thickness direction of the sheet, so that the cells have a flat shape extending in the MD direction. Therefore, the bubble diameter in the thickness direction is reduced, and the bubble density in the thickness direction is increased. The polypropylene resin foam sheet preferably has a bubble density (cell density) of 1.0×10 ³ to 3.0×10 ³ cells/mm ³ , and the bubble density means that the cells are relatively small. When the cell diameter is large, coalescence of the cells is likely to occur during the production of the polypropylene resin foam sheet. Stress concentrates in the vicinity of coalesced bubbles, and local deformation tends to occur, and the tensile elongation at break tends to decrease.

<Surface resistivity>
2. The polypropylene resin foam according to the present invention has a surface resistivity of 1.00×10 ¹³ Ω/□ or less, preferably 5.00×10 ¹² Ω/□ or less on its surface and sliced surface. It is more preferably 00×10 ¹² Ω/□ or less, and particularly preferably 1.00×10 ¹² Ω/□ or less. Since the lower the surface resistivity of the product, the better. Therefore, ^it is considered unnecessary to set the lower limit value for the product ^. Ω/□ or more is desirable.

According to a preferred embodiment of the present invention, it is possible to provide a transportation container , a partition member for a transportation container, or a cushioning material for packaging, which uses a polypropylene foam and is excellent in antistatic performance. When an antistatic agent is contained in the resin that constitutes the foam, the foam has a skin layer and a foam layer where there are no air bubbles near the surface of the foam, so the type of antistatic agent and the manufacturing process Depending on the method of adding the antistatic agent, the antistatic performance may differ due to differences in the distribution of the antistatic agent between the antistatic agent skin layer and the foam layer, and differences in the antistatic mechanism due to the difference in the antistatic agent. . In addition, in general, the foam layer may increase the surface resistivity used for evaluation of antistatic performance due to the air layer of bubbles, and the antistatic performance may decrease. The skin layer on the foam surface and the sliced or cut surface of the foam layer have excellent surface resistivity and can be used for a long period of time for the purpose of partitioning members for containers and transport containers or cushioning materials for packaging that can be used for a long period of time. Products and their use in antibacterial and antifungal applications can be provided. The product developed according to the preferred embodiment was excellent not only in antistatic performance but also in antibacterial and antifungal properties.

In addition, the product according to the preferred embodiment of the present invention can maintain antistatic performance even when the foam layer is exposed due to wear or damage on the surface of the product, and the growth of bacteria and mold on the surface of the product can be prevented. By suppressing , it is possible to sufficiently suppress the deterioration of products and the occurrence of defects caused by these factors.

As described above, the polypropylene resin foam of the present invention can be used as a transport container , a partition member of a transport container , or a cushioning material for packaging. Objects such as transportation are not particularly limited, but examples include electronic component applications. By using the transport container , the partition member of the transport container, or the cushioning material for packing according to the present invention, it is possible to suppress the generation of static electricity and preferably maintain the quality of electronic parts and the like. In particular, since the surface resistivity of the sliced surface is excellent, the transport container , the partition member of the transport container , or the cushioning material for packaging of the present invention can be used as a returnable container. It is also suitable for use as an antibacterial and antifungal agent because of its excellent properties .

<Manufacturing method of test material>
Test material 1 to test material 21 used in the examples were obtained by adding a predetermined amount of pigment to a resin component obtained by adding a BN type charge transfer type antistatic agent to the base resin of each test material if necessary. Then, 1 part of a cell nucleating agent is added, and carbon dioxide gas is expanded three times under the conditions of a gas pressure of 7 kg/cm ² and a gas flow rate of 5 l/min. After extrusion to a sheet thickness of 4.5 mm, roll Rolling was performed at a roll interval of 2.8 mm to finish a polypropylene resin foam having a thickness of 3.0 mm.
Here, polystyrene manufactured by Eiwa Kasei Kogyo Co., Ltd. was used as the bubble nucleating agent.
The BN type charge transfer antistat was added via a master patch. Here, each test material was prepared by using BN105 manufactured by Boron Laboratory Co., Ltd. as an antistatic agent, and using polyethylene (LDPE or HDPE) or polypropylene as a base resin, and a predetermined ratio of BN type charge transfer type charging. A masterbatch containing an inhibitor was melted and kneaded, extruded into a strand having a predetermined cross-sectional shape, and then cut into a predetermined size.

<Method of testing and measuring test material>
For the test material of Example 1 described later, the tensile strength was measured by a tensile test, the expansion ratio and the open cell rate were measured, and the surface resistance of the surface and sliced surface of the resin foam was measured 7 days and 30 days after the test material was manufactured. rate, charging half-life of the foam surface, and antibacterial evaluation test. Each test of tensile strength, foaming ratio, open cell ratio, surface resistivity, half-life of charging, and antibacterial test was conducted according to either JIS or ASTM standards.
Here, the material used for measuring the surface resistivity of the sliced surface was foamed at the center of the thickness direction of the resin foam with a thickness of 3 mm and the position corresponding to (1/4) of the sheet thickness of the foam on the surface. A specimen cut parallel to the body surface and processed into a test piece of a predetermined size was used.
Here, in Example 2, among the above measurement items of surface resistivity, the surface resistivity is measured only on the surface of the foam for all test materials, and the surface resistivity of the sliced surface is measured for a specific material described later, Other characteristics were measured in the same manner as in Example 1. In addition, as Example 3, in order to evaluate the antistatic performance of the representative material of Example 1 after a long period of time, the surface resistivity was measured only on the surface of the test material after holding it in a constant temperature bath at 60 ° C. for 35 days. An accelerated test was performed. In Example 3, only long-term property evaluation of surface resistivity was additionally performed, and the test material used in Example 3 overlapped with the test material of Example 1, so other than surface resistivity I didn't do the test because I didn't need to do it. In addition, the tensile strength, expansion ratio, and open cell ratio are measured for each of three test pieces, and the average value is used as the measured value. Taking this into consideration, five test pieces were measured, and the average was used as the measured value. The surface quality was evaluated by visual inspection of the resin foam surface of each test material, and the foamability was evaluated using a cut surface of the resin foam.
Here, in the description of each example in the tables to be described later, low-density polyethylene, high-density polyethylene, polypropylene, etc. are sometimes described in a simplified manner as LDPE, HDPE, PP, etc. in the tables of the examples, The direct blending method and the masterbatch method are indicated as DB and MB as the pigment charging method. The pigment masterbatch was produced in the same manner as the charge-transfer antistatic agent.

(Tensile strength)
The tensile elongation at break of the resin foam was determined according to JISK6767. More specifically, a No. 2 dumbbell test piece (thickness 3 mm) was used as the test piece, and a tensile test was performed at a tensile speed of 100 mm / min until the test piece broke. The tensile strength was obtained in both the MD direction and the TD direction, rounded off to two decimal places, and the measurement results were reported to one decimal place.

(Expansion ratio)
The expansion ratio is a value obtained by dividing the specific gravity of the resin before foaming by the specific gravity of the foam measured by the water substitution method (JISK7112). The specific gravity of the foam can be measured using an electronic balance AG204 manufactured by Metrade Red. For the measured value, the value rounded to the second decimal place was used as the foaming ratio. As a result of measuring the expansion ratio for each test material of Examples 1 and 2, the expansion ratio satisfied the expansion ratio of 3.0 ± 0.1 times (2.9 to 3.1 times) for each test material. 1 and Table 2 are omitted.

(Continuous cell rate)
The open cell rate (continuous rate) was determined according to the method described in ASTM D-2856-87. Specifically, the open cell ratio was determined by applying the measured value using an air comparison type densitometer Model 1000 (manufactured by Tokyo Science Co., Ltd.) to the following formula. The open cell ratio was determined to two digits after the decimal point, was measured for three test materials, was rounded off, and was determined to one digit after the decimal point to obtain the open cell ratio.
[Open cell ratio (%)] = 100 × [(apparent volume - volume value by air comparison type hydrometer)
/apparent volume]

(Measurement of surface resistivity)
Surface resistivity can be measured according to JISK6911. The surface resistivity measurement uses a main electrode, a ring electrode, and a counter electrode, applies a voltage source Vs to the ring electrode, and measures the current Im flowing on the surface of the sample from the ring electrode toward the main electrode. Here, the surface resistance value Rs can be calculated from Rs=Vs/Im.
Here, since the current flowing from the ring electrode to the counter electrode does not flow into the ammeter, it does not affect the measured current.

Let L be the average length of the outer diameter of the main electrode and the inner diameter of the ring electrode, and W be the distance between the outer diameter of the main electrode and the inner diameter of the ring electrode. Here, the test piece is pretreated at 20±2° C. and 65±5% humidity before the measurement.
ρs = (L / W) · Rs = (Π (D + d) / (D - d)) · (Vs / Im)
Surface resistivity: ρs
Inner diameter of ring electrode: D
Outer diameter of main electrode: d
Average length of outer diameter of main electrode and inner diameter of ring electrode: L = (D + d)/2
Distance between outer diameter of main electrode and inner diameter of ring electrode: W=(D−d)/2
Surface resistance: Rs
The surface resistance measurement rate is expressed in Ω/□ and expressed as a resistance value per 1 cm ² .
In the actual measurement, a test piece of 100 mm x 100 mm was cut out, and this was measured using a test apparatus having an inner diameter D of the ring electrode of 70 mmφ and an outer diameter d of the main electrode of 50 mmφ. R8340 manufactured by ADVANTEST Co., Ltd. was used as a testing device.

(Charging half-life measurement)
The charge half-life was measured with a static honesty meter by cutting out a test material having a sample size of 45 mm×45 mm for each test material under the following conditions.
Test method: JISL1094A method compliant Test conditions: Applied voltage; -10 kV
Application time; 30 s
Fixed number of test pieces: 3 Sample holding conditions: 23°C ± 2°C, 50% RH ± 2RH x 24h
Test environment: 23°C ± 2°C, 50% RH ± 2RH
Measuring device: Static Honestmeter Type H-011 (manufactured by Shishido Static Electricity Co., Ltd.)

(Evaluation method for surface quality and foamability of resin foam)
Here, when considering the use of the transportation container of the product of the present invention , the partition member of the transportation container , or the cushioning material for packing, the surface quality of the resin foam of these products becomes a problem. Therefore, since it is known that the surface quality of each test material is influenced by the stability during foaming, the relationship between surface quality and foamability was confirmed. The surface quality is evaluated by visual inspection. If the surface condition of the resin foam is uniform, "◎" is given, and if the surface of the resin foam is slightly uneven, there is no problem as a product. ◯”, and “x” when the foam had irregularities on the surface and uneven thickness. In addition, to check the state of foaming, the cross-section of the resin foam in the thickness direction was examined with a scanning electron microscope at a magnification of 50 times. When the foaming state was uniform regardless of the observation site, it was evaluated as "○", and when the foaming state was different depending on the observation site and was uneven, it was evaluated as "X".

(Antibacterial evaluation method)
In the test, an Escherichia coli kit manufactured by Microbiologics was inoculated into a liquid bouillon medium, cultured overnight in a constant temperature bath at 37° C., and the cultured bacterial solution adjusted to an appropriate concentration was used as the bacterial solution. Here, the medium used for the antibacterial test was a compact dry EC medium manufactured by Nissui Pharmaceutical Co., Ltd.

Here, the evaluation of the antibacterial properties was performed only on the skin layer on the surface of the foam of the test materials in Tables 1 and 2, which will be described later. The antibacterial evaluation test on the test material surface of each test material was carried out simply on only the antibacterial test piece without evaluating the untreated test piece with reference to JISZ 2801. Specifically, the target test piece was cut into a size of 50±2 mm square, and the test piece was brought into contact with the bacterial solution and allowed to stand at 37° C. for 24 hours. Thereafter, washing-out dilution was performed to a predetermined concentration, and the test solution after washing-out dilution was cultured for 1 day (37°C for 24 hours), and then the number of colonies of viable bacteria was measured. This operation was performed on each test piece, and the smaller the colony count of viable bacteria, the higher the antibacterial activity was evaluated.

Here, the number of colonies is calculated by multiplying the number of colonies actually measured by the dilution ratio, and thus is 10 ⁶ times the actual measured value. The measurement is performed with 5 petri dishes, and the average value of the measured values of the 5 petri dishes is rounded off to obtain the measured value, which is 10 ⁶ times this value. In the tables of the examples described later, the mean values of the Cn measured values omitting 10 ⁶ are described. Since the activity value is not determined in this application, it is considered sufficient to simply compare the measured values of each test material relative to each other.
Cn: number of colonies (average number of colonies in the petri dish used)
At: Dilution ratio (Dilution ratio of the diluted solution dispensed into the adopted petri dish: 10 ⁶ )
Ct = Cn x At = Cn x ¹⁰⁶

<Example 1>
(test material)
Tensile strength in MD direction and TD direction in tensile test with No. 2 dumbbell test piece of various polypropylene resin foams about test material 1 to test material 11, open cell rate, foam surface on 7 days and 30 days after production The measurement results of the surface resistivity of the sliced surface, the charging half-life measurement results by a static honesty meter, and the evaluation results of foamability and antibacterial properties are shown.
Here, the surface resistivity was not measured immediately after the product was manufactured, but after 7 days and 30 days. Therefore, the effect of cutting on the cell structure (replacement of carbon dioxide gas and air in the cells near the cut surface and a very small change in cell volume) and the progress of crystallinity of the BN type charge transfer antistatic agent Taking this into consideration, it was decided to measure the surface resistivity after about one week had passed.

Here, test material 1 to test material 7 are masters produced by mixing a BN type charge transfer type antistatic agent with LDPE as a polyethylene resin and a BN type charge transfer type antistatic agent in a predetermined ratio. Using a batch, the composition range of the masterbatch is 0.3 to 8.0 parts by mass of low density polyethylene resin (LDPE) and 0.1 to 2.0 parts by mass of BN type charge transfer type antistatic agent. A resin foam produced using a master batch in which a low density polyethylene resin (LDPE) and a BN type antistatic agent are mixed at a mixing ratio of 3:1 to 7:1. is. Here, the lower limit of LDPE as a polyethylene resin is the lower limit of the mixing ratio in the masterbatch, which is allowable up to 0.3 parts by mass, but the upper limit is the strength and heat resistance of the foam. It is necessary to adjust the mixing ratio of the masterbatch so that it becomes 8 parts by mass when it is not contained, and 10 parts by mass even when it contains a pigment or the like, which will be described later. As each test material, BN105 manufactured by Boron Laboratory Co., Ltd. was used by in-house production of a masterbatch of a predetermined ratio using polyethylene or polypropylene as a base resin. Test material 8 is a test material using high-density polyethylene (HDPE) as the base resin of the masterbatch of the charge-transfer antistatic agent , and was used as a reference example . Test material 9 is a test material using polypropylene (PP) as the base resin of the masterbatch of the charge-transfer antistatic agent , and was used as a comparative example . Both are test materials containing the same content of 1 part by mass of the BN type charge-transfer type antistatic agent although the base resin of the masterbatch is different from that of the test material 3. Here, the resin used as the base resin of the masterbatch is F218-O manufactured by Sumitomo Chemical Co., Ltd. for low-density polyethylene (LDPE) , HD1300 manufactured by Nippon Polyolefin Co., Ltd. for high-density polyethylene, and prime polymer for polypropylene. Prime Polypro E702MG manufactured by Co., Ltd. was used.

Here, the base resin A used in the test material of Example 1 is obtained by adding a homotype polypropylene and a block type polypropylene resin at a predetermined ratio (2:1), and the base resin B is a block type. Only the base resin is blended. Both have different material strength characteristics and open cell ratio due to the difference in the base resin. Base resin A is a high-strength resin foam, and base resin B is a low-strength resin foam. Here, in the test materials 1 to 9, the base resin A was basically used as the base resin, but only the base resin B was used in the test material 4.
The homotype polypropylene used for the base resins A and B of the resin foam is MFX8 manufactured by Nippon Polypropylene Co., Ltd., and the block type polypropylene is Prime Polypro E702MG manufactured by Prime Polymer Co., Ltd. It was used. Here, the base resin A is a mixture of the homotype polypropylene and the block type polypropylene at a ratio of 2:1, and the base resin B is a block type polypropylene, Prime Polypro E702MG manufactured by Prime Polymer Co., Ltd. only was used.

Test material 10 is a test material as a comparative example material using a polypropylene resin foam obtained by adding 2 parts of low-molecular-weight Kao surfactant-type antistatic agent ELASTOMASTER 320 to base resin A. The test material 11 is a laminated structure in which a polypropylene resin film obtained by adding a high-molecular type antistatic agent to the base resin A polypropylene resin is fused to the surface of the polypropylene resin foam by lamination extrusion. This is a test material as a comparative example material. Therefore, the test material 11 is Sumiceller ST (product name), which is a cushioning material using a resin foam with a laminated structure in which a film containing a polymer type antistatic agent is laminated on the surface manufactured by Sumika Plastech Co., Ltd. Although used, the resin foam as the support does not contain an antistatic agent.

(Tensile strength, open cell ratio)
Table 1 shows the test results. The base resin A is a hard foam material, and the base resin B is a soft foam material. Direction: 6.8 to 7.6 MPa, TD direction: 4.9 to 5.5 MPa, and the open cell rate is 10.7 to 12.4%. The tensile strength in the MD direction is 7.2 MPa in the MD direction, 5.4 MPa in the TD direction, and the open cell rate is 12.4%. It was 8.6 MPa, 5.6 MPa in the TD direction, and the open cell ratio was 11.8%. Further, the tensile strength of the base resin B of the test material 4 was 5.5 MPa in the MD direction and 3.4 MPa in the TD direction, and the open cell ratio was 58.4%. Here, the values of the above tensile strength and open cell ratio were within a range in which both the test material and the comparative material had no problem as a transportation container , a partition member for a transportation container, or a cushioning material for packing.

(Surface resistivity of resin foam surface)
As can be seen from Table 1, the surface resistivity of test materials 1 to 9 containing the BN type charge-transfer type antistatic agent 7 days after production was 0.1-2. In the range of 0 parts by mass, including the type of base resin of the masterbatch, it is 1.64 to 5.60×10 ¹¹ , and the surface resistivity one month after production is 1.48 to 2.97×10 ¹¹ Although there are individual differences in surface resistivity between materials, it is less than 10 ¹² in any case.
On the other hand, the test material 10 containing a surfactant-type antistatic agent, which is a comparative material, had a surface resistivity of 4.15 × 10 ¹¹ 7 days after production, which is included in the surface resistivity range of the present invention. However, the surface resistivity one month after production was 3.69×10 ¹¹ , which is higher than the surface resistivity of the present invention, and is considered to be at approximately the same level as a whole. In addition, the surface resistivity of the surface of the test material 11, which is a laminated structure material made of a polymer type antistatic agent, was 3.85 × 10 ¹¹ 7 days after production, which is the surface resistivity range of the present invention. However, the surface resistivity one month after production is 3.17×10 ¹¹ , which is higher than that of the present invention, and is considered to be at approximately the same level as a whole.

When comparing Test Material 1 and Test Material 10 containing two parts each of a BN type charge transfer antistatic agent and a low molecular weight antistatic agent, Test Material 1 was superior to Test Material 10. In addition, the surface resistivity of the test material 11, which is a laminated structure material made of a polymer-type antistatic agent, is unknown, but the polymer-type antistatic agent is usually added from the present invention, although the detailed content of the antistatic agent is unknown. Despite being considered to contain a large amount, it was inferior to the present invention.

(Surface resistivity of sliced surface of resin foam)
For the surface resistivity of the sliced surface, the sliced surface was obtained by cutting not at the center of the thickness of the product, but at a position 1/4 from the surface in the thickness direction of the resin foam in consideration of wear and damage of the product. In Table 1, the sliced surface obtained by cutting the foamed surface of 1/4 thickness from the surface of the resin foam is the sliced surface of test materials 1 to 9 containing the BN type charge transfer type antistatic agent of Example 1. The surface resistivity of is 1.48-2.56×10 ¹² after 7 days of manufacture and 3.34-5.13×10 ¹¹ after 1 month of manufacture.
In contrast, the low-molecular-weight surfactant-type antistatic agent was 8.24×10 ^{14 seven} days after production, and 2.75×10 ¹⁴ even one month after production. , the polymer-type antistatic agent is 8.26×10 ¹⁴ 7 days after production and 2.72×10 ¹⁴ even 1 month after production, both showing surface resistivities in the order of 10 ¹⁴ .
Therefore, test materials 1 to 9 of the present invention, regardless of the content of the BN type charge transfer type antistatic agent and the type of the base resin of the masterbatch, are low-molecular surfactant type antistatic agents Compared to test materials 10 and 11 containing a polymer type antistatic agent, the surface resistivity of the sliced surface tends to decrease remarkably. The reason for this is, for example, the difference in charge-removing mechanism from other materials of the semipolar BN type charge-transfer antistatic agent and the uniformity of the BN-type charge-transfer antistatic agent on the cell wall surface surrounding the air bubbles on the slice surface. It is considered that this is obtained as a result of a structure in which the particles are dispersed at a high density in the On the other hand, in the case of the test material 10 containing a surfactant-type antistatic agent, or in the test in which the sliced surface of the laminated structure using a polymer-type antistatic agent is a foamed layer of a resin foam that does not contain an antistatic agent. This is considered to be because such an effect cannot be obtained in the case of the material 11.

(Electrification half-life of resin foam surface)
Here, looking at the measurement results of the charging half-life of each test material, the charging half-life of the polypropylene resin foam containing the BN type charge transfer type antistatic agent of test materials 1 to 9 is 0.10 sec. While below, the charge half-life of the polypropylene resin foam containing the surfactant type antistatic agent of Test Material 10 is 0.12 sec, and the polypropylene resin containing the polymer type antistatic agent of Test Material 11 The charging half-life of the foam is 0.74 sec. In any case, the charging half-life of the polypropylene resin foam containing the BN type charge transfer type antistatic agent is smaller than the charging half-life of the comparative example materials of test materials 10 and 11. It is considered that the N-type charge-transfer type antistatic agent has a more uniform and fine dispersion of the antistatic agent than the comparative example materials of test materials 10 and 11 containing other antistatic agents.

(Evaluation results of surface quality and foamability)
The surface quality was evaluated by visual inspection, and there was no problem with the surface quality of the resin foam surfaces of test materials 1 to 7, and all of them were evaluated as "⊚". The surface of test material 8 is slightly inferior in the uniformity of the resin foam surface, and the surface resistivity is inferior to that of LDPE when compared with the same addition amount, so it was used as a reference example. In addition, test material 9 was evaluated as unacceptable with "x" because the thickness of the foam was uneven due to the unevenness of the surface. In addition, test material 10 and test material 11, which are comparative examples, had no problem in surface quality and both were evaluated as "⊚".

In addition, it is generally thought that when the resin component of the masterbatch and the resin component of the base resin are the same, the compatibility between the resins is excellent and the dispersibility is also excellent. However, the test results of the present invention are different. . As for the reason for this, since the product of the present invention is a foamed product, it is necessary to consider not only the compatibility of the masterbatch addition but also the effect on the foamability.
Therefore, according to the test results of the test material when polypropylene was used instead of low-density polyethylene (LDPE) as the resin component constituting the masterbatch of the BN type charge transfer antistatic agent of test material 9, the master When polypropylene is used as the resin that makes up the batch, the melting point of the resin that makes up the masterbatch is high and it is difficult for the masterbatch to melt into the base resin. As a result, the foaming state became uneven, and foaming was inhibited, resulting in a decrease in the surface quality of the polypropylene resin foam, which also affected the dispersibility of the antistatic agent. Conceivable. In addition, when high-density polyethylene (HDPE) is used as the resin constituting the masterbatch of test material 8, although not as much as when polypropylene is used, compared to when low-density polyethylene (LDPE) is used, The surface resistivity and surface quality of the resin foam were slightly lower, and both the surface resistivity and surface quality were not as good as those of low density polyethylene (LDPE) .

On the other hand, when the resin constituting the masterbatch containing the BN type charge transfer type antistatic agent is low density polyethylene (LDPE) or high density polyethylene ( HDPE) , the resin constituting the masterbatch is higher than polypropylene resin. , Since the melting points of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) are low, low-density polyethylene (LDPE) and high-density polyethylene (HDPE) are Since the density polyethylene (HDPE) is completely melted, it has less effect on the foaming process than when polypropylene is used as the base resin of the masterbatch, and has the effect of improving the dispersibility of the masterbatch. it is conceivable that. It is considered that this can also be estimated from the comparison of the charging half-life of test materials 3, 8 and 9.

Assuming that the melting point of polypropylene, which is the base resin of the masterbatch, is the same as that of the base resin A of the foam, the base resin A has a melting point of about 167°C, and the melting point of low-density polyethylene (LDPE) is about 167°C. 107 ° C., the melting point of high-density polyethylene (HDPE) is about 131 ° C., and the melting point of low-density polyethylene (LDPE) is low, so the dispersibility of the BN type charge-transfer antistatic agent in the polypropylene resin foam is , It is thought that the dispersibility of low-density polyethylene (LDPE ) is superior to the case where the base resin of the masterbatch is high-density polyethylene (HDPE), and the semi-conductive BN type electrolytic migration type antistatic agent Due to the difference in the static elimination mechanism and the fact that air bubbles are likely to occur on the cell wall surface at the interface between the BN type electrolytic transfer type antistatic agent and the base resin polypropylene of the resin foam, the surface resistivity of the sliced surface is It was considered that the value closest to the surface of the foam was shown compared with the case of other materials of the comparative examples.

(Antibacterial property of resin foam)
In addition, Table 1 shows the antibacterial properties after 10 ⁶ dilution in accordance with JISZ 2801 on the foam surface of each test material of test materials 1 to 9, 10, and 11. The foam surface of each test material The results of measuring the number of colonies are shown. According to this, the number of colonies when using the BN type charge transfer antistatic agent of test materials 1 to 9 is 20 to 65, whereas the number of colonies using the polymer type antistatic agent of test material 11 is 20 to 65. The number of colonies was 195 in the case of the resin foam, and from the results of the antibacterial test, the number of colonies was higher when the BN type charge transfer type antistatic agent was used than when the polymer type antistatic agent was used. It is considered that the number is small and the antibacterial property is excellent. In addition, the number of colonies when using the low-molecular-weight surfactant-type antistatic agent of test material 10 is 20, and when using the low-molecular-weight surfactant-type antistatic agent of test material 10, B- It is considered that the use of a low-molecular-weight surfactant-type antistatic agent is slightly superior to the case of using an N-type charge-transfer antistatic agent.

That is, the BN type charge transfer type antistatic agent according to the present invention exhibits antibacterial properties similar to those of surfactants, but does not cause the problem of bleeding out like surfactants, so it can be used as a continuous antistatic agent. It has the characteristics of having performance. Such performance is based on the findings of the present inventors, and a polypropylene resin foam product using this is constructed as having unique and novel properties conceptually.

(Comprehensive evaluation of the test material of Example 1)
As described above, from the results of Example 1, the resin foam containing the BN type charge transfer antistatic agent not only has antistatic performance on the surface of the resin foam, but also has antistatic properties on the sliced surface of the resin foam. It is also excellent in antistatic performance, and when compared with a polymer type antistatic agent having a similar sustained antistatic effect, such antistatic performance on the slice surface is better than that of the polymer type antistatic agent. In the case of test material 11, this was not recognized due to structural reasons such as the laminated structure consisting of a film containing an antistatic agent only on the surface.

Furthermore, from the antibacterial test, it was confirmed that the resin foam containing the BN type charge-transfer type antistatic agent has excellent antibacterial properties compared to the resin foam containing the polymer type antistatic agent. rice field. In addition, the resin foam containing the polymer type antistatic agent has the same surface resistivity as the resin foam containing the BN type charge transfer type antistatic agent, but the charge half-life is BN type. significantly higher than resin foams containing charge transfer antistatic agents. Such a difference in charge half-life is due to elimination of neutralization by static electricity between the polymer type antistatic agent and the BN type charge transfer type antistatic agent, as well as hole transport and electron diffusion inside the resin. In the case of a polymer type antistatic agent, the dispersal state of the antistatic agent is worse than that of the resin foam containing the BN type charge transfer type antistatic agent. It is presumed that this is due to the difference in the dispersion state of the inhibitor.

The result that the surface resistivity of the sliced surface of the resin foam containing the BN type charge-transfer type antistatic agent as described above is excellent is assumed to be used as a transportation container for electronic parts and a partition member for these. In addition, good antistatic effects can be obtained even when the surface of these members deteriorates due to vibration or abrasion during transportation, exposing the foam layer on the surface, or when the product comes into contact with the cut end surface of the partition member. Therefore, it can be suitably used for returnable applications. In addition, compared to resin foams containing polymer-type antistatic agents, it has excellent antibacterial properties, so it is considered to be excellent in antibacterial and antifungal properties in transportation containers. It is considered that even in a high humidity environment, it is difficult for mold and fungi to propagate.

<Example 2>
In Example 2, Table 2 shows the test results of test material 12 to test material 21 when metal phthalocyanine pigments and other pigments were added to test material 3 of Example 1 in predetermined ranges. Test material 12 to test material 15 are obtained by adding a Cu phthalocyanine pigment by changing the content in the range of 4.0 to 0.5 parts by mass. Test materials 17 to 19 are test materials obtained by adding 2 parts by mass of Fe phthalocyanine pigment, Co phthalocyanine pigment and Ni phthalocyanine pigment to Test material 3 of Example 1, respectively. The test material 20 is a material obtained by adding 2.0 parts by mass of titanium oxide to the test material 3, and the test material 21 is similarly obtained by adding 2.0 parts by mass of iron oxide to the test material 3.
In the present invention, the pigment is basically added by the direct blend method. Masterbatch: A pigment masterbatch in which the composition ratio of low-density polyethylene (LDPE) and pigment is 2:1 is sometimes used, so in the present invention, the addition of the pigment of the test material 16 is the addition of the masterbatch, and the other The test material was a direct blend. A comparison between the test material 16 and the test material 14 to which the same amount of Cu phthalocyanine pigment was added was made possible.

The Cu, Fe, and Co phthalocyanines used in Example 2 were obtained from Tokyo Chemical Industry Co., Ltd., Ni phthalocyanine was obtained from Fuji Photo Wako Pure Chemical Industries, Ltd., and titanium oxide was obtained from Ishihara Sangyo Co., Ltd. , iron oxide manufactured by Dainichi Seika Kogyo Co., Ltd. was used. The masterbatch of test material 16 used low-density polyethylene (LDPE) as the base resin, and the mixing ratio of low-density polyethylene (LDPE) and Cu phthalocyanine was 2:1.

Here, the surface resistivity of the test material surface was measured for all the test materials from test material 12 to test material 21 in Table 2. Only test materials 13, 14, and 16 were measured on the sliced surface obtained by cutting the foamed surface with a thickness of 1/4 from the surface of the resin foam in the same manner as in the case. As for the test material 9, the surface resistivity measurement was stopped because the surface of the test material became uneven and the surface state became unstable, and a stable contact state with the main electrode and the ring electrode could not be obtained. Here, test material 14 and test material 16 are materials with the same composition to which 2 parts by mass of Cu phthalocyanine pigment are added, but the pigment addition method is the direct blend method (DB) and the masterbatch method (MB). Only different.

(Various test results of test material)
Since the test material in Example 2 contains a predetermined pigment in the test material 3 of Example 1, the tensile strength of the test material, the open cell rate, the surface resistivity of the resin foam surface, the charge Almost the same results as in Example 1 were obtained for the damping rate, the surface quality of the resin foam, and the foamability.
Specifically, the surface resistivity of the surface of the test material 3 was 2.07×10 ¹¹ seven days after production and 1.88×10 ¹¹ one month after production. The surface resistivity on the surface when a predetermined amount of pigment of test material 22 was added from 13 to 22 was 2.03 to 2.18×10 ¹¹ seven days after production, and 1.84 to 2.04× one month after production. At 10 ¹¹ , the surface resistivity is in the range of ± about 10% of the surface resistivity of test material 3, using test material 3 as a reference. In addition, the surface resistivity of the sliced surfaces of the test materials 13, 14, and 16 is within a range of about ±10% of the surface resistivity of the sliced surface of the test material 3 when the test material 3 is used as a reference. It is the same level as test material 3. On the other hand, the surface resistivity of the sliced surface of the comparative example material is on the order of 10 ¹⁴ , and the test materials 13, 14 and 16 of the present invention have much lower values than the test materials 10 and 11 of the comparative example. showing. For this reason, other pigment-added test materials are considered to exhibit similar tendencies, and therefore the surface resistivity of other test materials was not measured.
In addition, in order to evaluate the effect of the pigment addition method on the various characteristics of the test material, the test material 14 and the test material 16 were directly blended and masterbatch added between the test materials to which 1 part by mass of Cu phthalocyanine was added. However, no significant difference was found between the direct blend and the masterbatch addition.
Test material 12 to test material 21 described in Example 2 have tensile strength, open cell ratio, surface resistivity in a predetermined number of days after production, and charge half-life, since the pigment is stable in the extrusion foaming process. Although there are some differences due to the difference in the material, there is no big difference that would cause a practical problem in mechanical properties, open cell ratio, etc. Conceivable.

(Antibacterial effect by pigment of test material)
When comparing the results of the antibacterial test on the foam surface of the test material containing the metal phthalocyanine pigment of test material 12 to test material 19 and the foam surface of test material 3, the number of colonies in test material 3 is 37, In the case of test material 12 to test material 19, the number of colonies showed a value of zero or 5 or less. It was found that the resin foam to which the metal phthalocyanine pigments were added in this way had a significantly reduced number of colonies compared to the material to which these pigments were not added, showing an antibacterial effect. The test material 20 containing titanium oxide and the test material 21 containing iron oxide have a small number of colonies of 20, but the antibacterial properties are improved by containing the metal compound pigment compared to the material without pigment addition. However, the effect is not so remarkable as compared with the case of metal phthalocyanine.

Here, the reason why the resin foam to which the metal phthalocyanine pigment is added exhibits antibacterial properties is that the metal part forming the phthalocyanine structure of the pigment having the metal phthalocyanine structure is typically Cu, but Fe, Fe, In either case of Ni or Co, since the metal phthalocyanine structure has an oxidizing action, it is thought that it has antibacterial and antifungal properties by inhibiting either the formation or proliferation of fungi, metabolism, or cell membranes. be done.

In the present invention, only the antibacterial test was performed, and the antifungal test was not performed. BN-type charge-transfer antistatic agents and metal phthalocyanines are thought to possess not only antibacterial but also antifungal properties because they are multicellular eukaryotes that evolved from .

<Example 3>
Further, as Example 3, in order to evaluate the antistatic performance after a long period of time for the test material 3, test material 10, and test material 11 described in Example 1, after holding for 35 days in a constant temperature bath at 60 ° C. , the surface resistivity was evaluated by an accelerated test for measuring the surface resistivity of the surface layer of these test materials. Since it can be considered that Arrhenius' 10 ° C. double rule can be applied to the holding time of this accelerated test, if the 60 ° C. holding time is converted to holding at room temperature based on this, the holding time at 20 ° C. room temperature conversion corresponds to about 1.5 years.

As a result, the surface resistivity of the material containing 2 parts by mass of the BN type charge-transfer type antistatic agent of test material 3 was 1.60 × 10 ¹⁰ , and the polymer type antistatic agent of test material 11 was abundant. The surface ^resistivity of the laminate type ^containing and the surface resistivity of test material 10 was remarkably higher than that of test material 3 and test material 11. This is because the test materials using the long-lasting antistatic agents of test material 3 and test material 11 have a long-lasting effect of the antistatic agent, so in the accelerated test corresponding to the test period of one and a half years The surface resistivity was less than 10 ¹³ , but the test material 10 containing the surfactant type antistatic agent bleed out during the holding of the antistatic agent at 60 ° C. for 35 days. It is considered that the surface resistivity was remarkably high because it disappeared from the surface.

(Overall summary of test results)
Here, from the results in Table 1, all ^the test materials containing the BN type charge transfer antistatic agent of the present invention have a surface resistivity of 10 ¹² or less on the sliced surface. On the other hand, both the test material 10 containing a low-molecular surfactant type antistatic agent and the laminated type test material 11 containing a polymer type antistatic agent have a surface resistivity of 10 ¹⁴ on the sliced surface. has become more than

Furthermore, the test material containing a low-molecular-weight antistatic agent was compared to the test material of the present invention, and the surface resistivity measurement test results after holding in a constant temperature bath at 60 ° C. for 35 days and Table 1 without acceleration test Judging the long-term usability of the product of the present invention from the measurement results of the surface resistivity of the sliced surface in Table 2, the returnable transport container having continuous antistatic performance and the partition member for the transport container of the present invention Alternatively, it is a material that is not suitable for packing cushioning materials, and in the case of a polymer type antistatic agent, the long-term usability by evaluating the surface resistivity by an accelerated test is almost the same as the product of the present invention. The surface resistivity of the sliced surface was inferior to that of the product of the present invention, and the antibacterial and antifungal properties were also inferior to those of the present invention.

In addition, in comparison with polymer type antistatic agents, the surface resistivity of the material surface is considered to be almost the same except for the surface resistivity of the sliced surface and the antibacterial and antifungal properties. There is a large difference in content. Generally, the polymer type antistatic agent is contained in a content ratio of 5 parts by mass or more to about 10 parts by mass with respect to the base resin, but in the case of the BN type charge transfer type antistatic agent of the present invention, It is considered that a content in the range of 0.1 to 2.0 parts by mass has the same effect. The reason for this is the difference in the dispersion state of the antistatic agent due to the masterbatch of the BN type charge transfer type antistatic agent with low density polyethylene (LDPE) and the charge disappearance of the BN type charge transfer type antistatic agent. This is considered to be due to the difference in mechanism.

In the present invention, from the results of Example 2 already described, it is considered that the antibacterial and antifungal effects of the pigment are superimposed on the antibacterial and antifungal effects of the BN type charge-transfer antistatic agent. was taken. The reason for the antibacterial and antifungal effects of the BN type charge transfer antistatic agent is unknown, but the antibacterial and antifungal effects of the metal phthalocyanine pigments are due to the oxidation effect of the metal phthalocyanine pigments on the metabolism of fungi and molds and the cell membranes. This was thought to be due to an inhibitory effect that inhibited either the generation or proliferation of

Here, the reason why the antibacterial property was evaluated only on the surface of the foam and not the sliced surface was that the effect of the air layer of the surface bubbles was not as remarkable as the surface resistivity, and the antibacterial property of the material composition was not affected. This is because at least substantially the same effect can be expected for the skin layer on the surface of the foam and the sliced surface. The reason for this is that the apparent cross-sectional area of the sliced surface is larger than that of the skin layer without air bubbles, and the effective surface area is increased due to the formation of microscopic irregularities on the surface by the air bubbles. Three dimensions in the foaming process of B—N type charge transfer antistatic agents by substantially increasing the surface area of type charge transfer antistatic agents and using low density polyethylene resin (LDPE) in the masterbatch This is because at least the same effect can be expected on the surface and the sliced surface because the effect of exposing the bubbles to the surface of the cell wall and the effect of dispersing the bubbles during deformation can also be expected. Therefore, for confirmation, an antibacterial test was performed on the sliced surface (1/4 surface of the sheet thickness) of test material 3, and the number of colonies on the sliced surface was 34 compared to 37 colonies on the surface of the foam. , it was confirmed that the antibacterial properties of the sliced surface were almost the same as those of the foam surface.

According to the present invention, a polypropylene resin foam containing LDPE as a low-density polyethylene resin and a BN type charge transfer antistatic agent as a sustained charge antistatic agent in a predetermined range and having excellent antistatic performance on the foam surface and sliced surface. A transportation container, a partition member for a transportation container , or a cushioning material for packaging having a long-lasting antistatic property using a body was obtained. Transportation containers , partition members for transportation containers, and cushioning materials for packaging having sustained antistatic performance using these polypropylene resin foams have not only an antistatic effect but also an antibacterial effect. Products using these resin foams are allowed to contain a pigment within a predetermined range. In addition to these effects, remarkable antibacterial and antifungal effects can be expected without impairing the long-lasting antistatic action of BN type charge-transfer antistatic agents. Therefore, these products can be used as returnable transportation containers , partitioning members for transportation containers, or cushioning materials for packaging, although they have long-lasting antistatic performance and antibacterial and antifungal properties.

Here, the product using the polypropylene resin foam of the present invention can be produced using a masterbatch in which LDPE and a BN type charge-transfer type antistatic agent are combined at a predetermined ratio as a low-density polyethylene resin. As it becomes possible, the present invention provides methods of making these products. Since the base resin is polypropylene resin, the masterbatch BN type charge transfer antistatic agent uses LDPE, which is a low-density polyethylene resin having a lower melting point than the polypropylene base resin during melt kneading. is preferred. As a result, in addition to the compatibility of the masterbatch, the dispersibility of the antistatic agent is improved, and by making it easier to generate air bubbles at the interface between the masterbatch and the base resin, on the slice surface, the cell wall surface surrounding the air bubbles It was considered that the dispersion of a large amount of the BN type charge-transfer type antistatic agent resulted in excellent antistatic performance and foamability.

Furthermore, the present invention provides a transportation container , a transportation container using a polypropylene resin foam produced by a method for producing a polypropylene resin foam for a transportation container, a partition member of a transportation container , or a cushioning material for packaging. It becomes possible to provide the use of partition members or cushioning materials for packaging for antibacterial and antifungal applications.

Furthermore, the present invention provides a transport container , a partition member for a transport container , or a cushioning material for a transport container using a polypropylene resin foam for a transport container , a partition member for a transport container, or a cushioning material for packaging. It becomes possible to provide use for antifungal applications.

Although the embodiments of the present invention have been described above, the technical scope of the present invention is not affected by the above-described embodiments. It is obvious that a person skilled in the art can correspond to various modifications or modifications within the scope of the technical idea described in the claims, and these are also within the technical scope of the present invention. be understood to belong to For example, it goes without saying that the embodiments described above can be combined with each other.

With the BN type charge transfer type antistatic agent confirmed by the antibacterial test conducted according to the following antibacterial test method with reference to JIS Z2801 for the transport container, the partition member of the transport container, or the cushioning material for packaging The antibacterial effect or antifungal effect of the extruded polypropylene resin foam sheet containing the metal phthalocyanine compound was confirmed by the repeated use of the polypropylene extruded resin foam sheet having a viable colony count of 5×10 ⁶ or less in the above test. It may be a transport container, a partition member for a transport container, or a cushioning material for packing.
As an antibacterial test method at this time, a test piece to be tested is cut into a size of 50±2 mm square, and the test piece is brought into contact with the bacterial solution and allowed to stand at 37° C. for 24 hours. Thereafter, washing-out dilution is performed to a predetermined concentration, and the test solution after washing-out dilution is cultured for one day, and then the colony count of viable bacteria may be measured. The number of colonies is a value obtained by multiplying the measured number of colonies by the dilution ratio, and is therefore 10 ⁶ times the actual measured value.

The extruded polypropylene resin foam used for the transport container, the partition member of the transport container, or the cushioning material for packaging contains a flame retardant such as an antimony flame retardant, a hydroxide flame retardant, or a brominated flame retardant. It may be a reusable shipping container, a partitioning member for a shipping container, or a cushioning material for packing, which uses a polypropylene extruded resin foam sheet characterized by containing in the range of 0 to 4.0 parts by mass.

Claims (10)

Sustained charging composed of a polypropylene resin foam containing a polypropylene resin as a base resin and a BN type charge transfer type antistatic agent in the range of 0.1 to 2.0 parts by mass with respect to the base resin It is a transport container or a partition material for a transport container or a cushioning material for packaging having a preventive performance, and the surface resistivity of the foamed resin layer on the surface and sliced surface of the polypropylene resin foam measured in accordance with JISK6911 is 1.00. A transport container, a partition material for a transport container, or a cushioning material for packing, characterized by having a resistance of ×10 ¹³ Ω/□ or less. The resin foam surface has a surface resistivity of 1.0×10 ¹² Ω/□ or less, and the sliced surface has a surface resistivity of 5.0×10 ¹² Ω/□ or less, measured according to JISK6911 of the polypropylene resin foam. 2. The transport container according to claim 1, the partition material for the transport container, or the cushioning material for packing. The polypropylene resin foam used for the transport container or the partition material of the transport container or the cushioning material for packing contains 0.3 to 8.0 parts by mass of polyethylene resin with respect to 100 parts by mass of the polypropylene resin. 3. The container for transportation according to claim 1 or claim 2, the partition material for the container for transportation, or the cushioning material for packing. The polypropylene resin foam used for a transport container, a partition material for a transport container, or a cushioning material for packaging contains 0.3 to 10 parts by mass of a polyethylene resin, and further contains a white pigment, a yellow pigment, a blue pigment, a green pigment, and a red pigment. , a black pigment in a range of 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the polypropylene resin. dividers and cushioning materials for packaging. 5. The transportation container or transport according to claim 4, wherein the pigment is a metal phthalocyanine compound, and the metal phthalocyanine compound is a pigment of any one of Cu, Co, Fe, and Ni metal phthalocyanine compounds. Container dividers and packing cushioning materials. 6. The transport container or the transport container according to any one of claims 1 to 5, wherein the transport container or the partition material and packing cushioning material of the transport container are antibacterial or antifungal. dividers and cushioning materials for packaging. With respect to 100 parts by mass of polypropylene resin, the content of the BN type charge transfer type antistatic agent is 1/4 times or less with respect to the total weight of the master batch of the BN type charge transfer type antistatic agent with the polyethylene resin. 0.4 to 10 parts by mass or less of the masterbatch is added to 100 parts by mass of the base polypropylene resin, melt kneading is performed, gas foaming is performed during melt kneading, and the polypropylene resin is 100 parts by mass. A transport container or a partition material for a transport container containing 0.3 to 8.0 parts by mass of a polyethylene resin and 0.1 to 2.0 parts by mass of a B—N charge transfer antistatic agent. A transport container, a method for producing a polypropylene resin foam for a partition material of a transport container, or a polypropylene resin foam for a cushioning material for packaging, comprising manufacturing a polypropylene resin foam for a cushioning material for packaging. The polypropylene resin foam contains 0.3 to 10 parts by mass of the polyethylene resin, and further contains 0.5 to 4.0 parts by mass of the pigment with respect to 100 parts by mass of the polypropylene resin, and the pigment is 8. The transport container or transport container according to claim 7, wherein the metal phthalocyanine compound is a pigment of any one of Cu, Co, Fe, and Ni metal phthalocyanine compounds. A method for manufacturing a polypropylene resin foam for use as a partition material or a cushioning material for packaging. Polypropylene resin foam for use as a transport container, a partition material for a transport container, or a cushioning material for packaging according to claim 7 or claim 8, wherein the polyethylene resin forming the masterbatch is low-density polyethylene. manufacturing method. Transportation using a polypropylene resin foam produced by the method for producing a polypropylene resin foam for a transportation container or a partition material for a transportation container or a cushioning material for packaging according to any one of claims 7 to 9 Use for antibacterial and antifungal applications in partitions and cushioning materials for packing containers and shipping containers.