JP7116885B1 - Thermoplastic composite resin - Google Patents

Abstract

Kind Code: A1 The present invention provides a thermoplastic composite resin that can be produced by a simple process, contains a volatile substance, and has a sustained release property of the volatile substance. A thermoplastic composite resin of the present invention contains a thermoplastic resin, cellulose nanofibers, an ethylene-based copolymer, and a volatile substance, and the ethylene-based copolymer is ethylene-methyl It is at least one selected from the group consisting of methacrylate copolymers, ethylene-methyl acrylate copolymers, and ethylene-vinyl acetate copolymers, and has sustained release of the volatile substance. [Selection figure] None

Description

TECHNICAL FIELD The present invention relates to thermoplastic composite resins with sustained release of volatile substances.

Thermoplastic resins are used for various purposes because they are easy to mold. The melting and kneading method is widely used for molding and processing thermoplastic resins, and according to this method, the thermoplastic resin must be heated to a high temperature of about 200°C. Therefore, when the thermoplastic resin and volatile substances are kneaded together, the volatile substances volatilize. There is a problem that it is difficult to equip them with sexuality.

Patent Document 1 discloses a deliquescent compound and a volatile compound-impregnated polylactic acid or polylactic acid copolymer that actively absorbs water (water vapor) in the air. Although it is disclosed that the emission of volatile compounds can be increased, there is the problem that multiple steps are required for manufacturing.

JP 2013-35779

The present invention provides a thermoplastic composite resin that can be produced by a simple process, contains a volatile substance, and has a sustained release property of the volatile substance.

The present invention for solving the above problems has the following contents.

A thermoplastic composite resin containing a thermoplastic resin, cellulose nanofibers, an ethylene-based copolymer, and a volatile substance,
The thermoplastic resin is one or more selected from among polyethylene, polypropylene, polystyrene, polylactic acid, ABS resin, vinyl chloride resin, and elastomer resin,
The ethylene-based copolymer is at least one of ethylene-methyl methacrylate copolymer and ethylene-methyl acrylate copolymer,
It has a sustained release property of the volatile substance.

Each glucose on the surface of the cellulose nanofiber has almost all secondary hydroxyl groups.

The cellulose nanofibers are uniformly dispersed in the thermoplastic composite resin.

The method for producing the thermoplastic composite resin includes at least one thermoplastic resin selected from polyethylene, polypropylene, polystyrene, polylactic acid, ABS resin, vinyl chloride resin, and elastomeric resin, and an aqueous dispersion of cellulose nanofibers. , at least one ethylene-based copolymer such as ethylene-methyl methacrylate copolymer or ethylene-methyl acrylate copolymer, and a volatile component are kneaded while heating at the melting temperature of the thermoplastic resin. - A kneading process,
and a water vaporization step of vaporizing water contained in the four-dispersion of cellulose nanofibers during the heating and kneading.

The thermoplastic composite resin of the present invention contains a volatile substance and has sustained release of the volatile substance. The thermoplastic composite resin of the present invention retains volatile substances even after repeated heating and dissolution, and has sustained release properties. Therefore, it can be molded into a processed product or the like while containing a volatile substance and maintaining a sustained release property. And it can be manufactured by a simple process using existing equipment.

By adding the ethylene-based copolymer to the thermoplastic resin, the cellulose nanofibers are uniformly dispersed in the thermoplastic resin without aggregation. Then, due to the action of cellulose nanofiber etc. added to the thermoplastic resin, the volatilization of volatile substances during heating and kneading in the manufacturing process is suppressed, the volatile substances remain, and the volatile substances are gradually released. It becomes a thing with sexuality.

Hereinafter, examples of embodiments of the present invention will be described. In addition, the present invention is not limited to the examples of the following forms.

The thermoplastic composite resin of the present invention contains a thermoplastic resin, cellulose nanofibers, an ethylene-based copolymer, and a volatile substance. The ethylene copolymer is at least one of ethylene-methyl methacrylate copolymer and ethylene-methyl acrylate copolymer. The thermoplastic composite resin of the present invention has sustained release of the volatile substance.

The thermoplastic resin contained in the thermoplastic composite resin of the present invention is not particularly limited, and commonly used thermoplastic resins can be used. As an example, one or more of polyethylene, polypropylene, polystyrene, polylactic acid, ABS resin, vinyl chloride resin, elastomeric resin and the like are selected and used.

"Cellulose nanofibers" in the present specification and the like are not limited to those having a size of 100 nm or less in any direction. The following nano-sized ones are also included.

The cellulose nanofibers contained in the thermoplastic composite resin of the present invention may, for example, have an average fiber system of about 3 nm to 100 nm, and the length of the cellulose nanofibers may be micron-sized. The cellulose nanofibers may be single cellulose nanofibers, microfibrillated cellulose nanofibers, or a mixture thereof.

The method for preparing the cellulose nanofibers is not particularly limited, and preparation is performed by defibrating raw cellulose fibers. Methods of defibration treatment include mechanical fibrillation treatment and chemical fibrillation treatment. As the mechanical fibrillation treatment, for example, a method using a so-called high-pressure homogenizer, in which a dispersion of raw material cellulose fibers is jetted from a pair of nozzles at a high pressure of about 100 MPa to 250 MPa, and the jet streams collide with each other to pulverize. There is

The chemical defibration treatment includes, for example, a method of oxidizing raw material cellulose fibers using an oxidation catalyst or the like. As a result, the hydroxyl group at the C6 position of each glucose unit in the cellulose molecule is selectively oxidized to a carboxy group, and the fibrils are chemically defibrated by mutual electrostatic repulsion. After that, dispersion treatment is performed using a device such as a homogenizer. As the oxidation catalyst, for example, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) or the like is used.

Cellulose nanofibers obtained by mechanical fibrillation treatment, chemical fibrillation treatment, or the like form an aqueous dispersion. An aqueous dispersion of cellulose nanofibers is a dispersion containing water as a dispersion medium. The entire amount of the dispersion medium is preferably water, but other liquids compatible with water (lower alcohols having 3 or less carbon atoms, etc.) can also be used as part of the dispersion medium.

Since the aqueous dispersion of cellulose nanofibers is not subjected to a modification treatment such as hydrophobization of the hydroxyl groups of the cellulose nanofibers, each glucose on the surface of the cellulose nanofibers in the aqueous dispersion of cellulose nanofibers is It has all or preferably almost all secondary hydroxyl groups. The thermoplastic composite resin of the present invention is obtained by heating and kneading the aqueous dispersion of cellulose nanofibers and gradually vaporizing the water in the aqueous dispersion of cellulose nanofibers. The secondary hydroxyl group of each glucose in is not denatured. Therefore, each glucose on the surface of the cellulose nanofiber contained in the thermoplastic composite resin of the present invention has almost all secondary hydroxyl groups.

The thermoplastic composite resin of the present invention suppresses aggregation of cellulose nanofibers by the ethylene-based copolymer, and provides a compatibilizing effect between the hydrophobic thermoplastic resin and the hydrophilic cellulose nanofibers. Therefore, the cellulose nanofibers are uniformly dispersed in the thermoplastic resin without aggregation.

In the aqueous dispersion of cellulose nanofibers, the average fiber diameter of the cellulose nanofibers in the aqueous dispersion is preferably about 3 nm to 100 nm, more preferably 20 nm to 50 nm. Since the thermoplastic composite resin of the present invention is obtained by heating and kneading an aqueous dispersion of cellulose nanofibers, the fiber diameter of the cellulose nanofibers uniformly dispersed in the thermoplastic composite resin is the raw material. It is almost the same as the fiber diameter of the cellulose nanofibers in the aqueous dispersion, preferably about 3 nm to 100 nm, more preferably 20 nm to 50 nm.

The aspect ratio of the cellulose nanofibers is not particularly limited, and is, for example, 100-500, preferably 100-200.

"Aspect ratio" means the ratio of the average fiber length to the average diameter (average fiber length/average diameter) in cellulose nanofibers. The average diameter and average fiber length of cellulose nanofibers can be measured by scanning electron microscopy (SEM). For example, a dispersion in which cellulose nanofibers are dispersed is cast on a substrate and observed with an SEM, and the diameter and length values are read for 20 or more fibers per image obtained, and these are printed on at least three images. images of non-overlapping regions to obtain diameter and length information for a minimum of 30 fibers. The average diameter can be calculated from the obtained fiber diameter data, the average fiber length can be calculated from the length data, and the aspect ratio can be calculated from the ratio between the number average fiber length and the average diameter.

The content of cellulose nanofibers in the thermoplastic composite resin of the present invention is not particularly limited. As an example, if the thermoplastic resin is 100 parts by mass, the content of cellulose nanofibers is about 0.01 parts by mass or more and about 0.05 parts by mass. Part or less.

The ethylene copolymer contained in the thermoplastic composite resin of the present invention is at least one of ethylene-methyl methacrylate copolymer and ethylene-methyl acrylate copolymer, preferably ethylene-methyl methacrylate copolymer. use.

The content of the ethylene copolymer in the thermoplastic composite resin of the present invention is not particularly limited. Part or less.

The volatile substance contained in the thermoplastic composite resin of the present invention is a substance that easily volatilizes into the atmosphere at normal temperature and normal pressure (25° C., 1 atm), such as fragrances, insect repellents, disinfectants, deodorants, and pharmaceuticals. is mentioned. These volatile substances are not particularly limited, and generally known substances can be used.

As the fragrance, generally known ones such as natural fragrances and synthetic fragrances can be used. Examples of natural fragrances include lavender oil, sweet orange oil, lemon oil, geranium oil, grapefruit oil, spearmint oil, sage oil, clove oil, peppermint oil, eucalyptus oil, rosemary oil, cutlet oil, bergamot oil, and sandalwood. oil and the like. Examples of synthetic fragrances include limonene, linalool, menthol, anethole, citronellal, and eugenol.

Insect repellents include transpirationable pyrethroids such as empentrin and derivatives thereof, pyrethroid agents and derivatives thereof, synthetic drugs such as DEET and picaridin, natural drugs such as plant-derived components such as menthanediol, and derivatives thereof.

Examples of the antibacterial agent include natural or synthetic antibacterial agents, cedar oil, shell ginger oil, lemongrass, hinokitiol, capsaicin, copper nonylphenolsulfonate, and zineb.

Examples of the disinfectant include unsaturated aldehydes such as cinnamic aldehyde and perillaldehyde, phenols such as eugenol and thymol, allyl sulfides, and isothiocyanates.

Deodorants include materials suitable for sensory methods (masking methods) and chemically reactive methods (neutralization methods, condensation methods, addition methods, adsorption reaction methods, etc.). Materials suitable for sensory methods include formaldehyde-containing materials, glyoxal, glutaraldehyde, maleates, menthol, aromatic carboxylic acids, and the like. Materials suitable for the chemical reaction method include flavanols and derivatives thereof, polyhydric phenols, extracts (including essential oils) from plant bark, leaves, stems, etc., wood vinegar components, and the like.

Pharmaceuticals include indomethacin farnesil, zaltoprofen, felbinac and the like.

The volatile substance may be solid or liquid, and multiple volatile components may be used in combination. The content of the volatile component in the thermoplastic composite resin of the present invention is not particularly limited, and as an example, if the thermoplastic resin is 100 parts by mass, the volatile component is about 1 part by mass or more and about 10 parts by mass or less. .

Other raw materials can be added to the thermoplastic composite resin as long as they do not impair the effects of the present invention. Other raw materials, for example, plasticizers, stabilizers, antioxidants, ultraviolet absorbers, lubricants, release agents, antistatic agents, fillers, coloring agents, foaming materials, flame retardants, etc., are selected from one or more. is selected and added.

Next, the method for producing the thermoplastic composite resin of the present invention will be described.

The method for producing a thermoplastic composite resin of the present invention comprises at least one thermoplastic resin selected from polyethylene, polypropylene, polystyrene, polylactic acid, ABS resin, vinyl chloride resin, and elastomeric resin, and water of cellulose nanofibers. The dispersion , at least one ethylene-based copolymer such as an ethylene-methyl methacrylate copolymer or an ethylene-methyl acrylate copolymer, and a volatile component are kneaded while being heated at the melting temperature of the thermoplastic resin. and a moisture vaporizing step of vaporizing moisture contained in the aqueous dispersion of cellulose nanofibers during the heating and kneading.

First, the heating/kneading process will be described.

A thermoplastic resin, an aqueous dispersion of cellulose nanofibers, an ethylene-based copolymer, and a volatile substance are charged into a commonly used kneading extruder. The order of adding the thermoplastic resin, the aqueous dispersion of cellulose nanofibers, the ethylene copolymer and the volatile substance is not particularly limited, and they may be added at the same time. As an example, in order to improve the kneading time and the kneading state, the thermoplastic resin, the aqueous dispersion of cellulose nanofiber, the ethylene-based copolymer and the volatile substance are mixed in advance and then put into the kneading extruder. do.

The thermoplastic resin and the ethylene-based copolymer are not particularly limited, and generally used or commercially available ones may be used. The shape is also not particularly limited, and pellets and powders are used as examples.

The aqueous dispersion of cellulose nanofibers is not particularly limited, and those that are commonly used or sold may be used. As an example, the solid content concentration of cellulose nanofibers in the aqueous dispersion of cellulose nanofibers is set to 10% by mass or less, preferably about 1% by mass, relative to the entire aqueous dispersion of cellulose nanofibers. % or more and about 5 mass % or less.

Volatile substances are not particularly limited, and commonly used or commercially available substances may be used. Examples include fragrances, insect repellents, bactericides, deodorants, pharmaceuticals, and the like.

As an example, if the amount of the thermoplastic resin to be mixed is 100 parts by mass, the water dispersion of cellulose nanofibers is about 1 part by mass or more and about 5 parts by mass or less, and the ethylene copolymer is about 5 parts by mass or more and about 15 parts by mass. part or less, and the volatile substance is about 1 part by mass or more and about 10 parts by mass or less.

When adding other raw materials such as plasticizers, stabilizers, antioxidants, ultraviolet absorbers, lubricants, release agents, antistatic agents, fillers, coloring agents, foaming materials, flame retardants, etc., thermoplastic The resin, the aqueous dispersion of cellulose nanofibers, the ethylene-based copolymer, and the volatile substance are kneaded at the same time. Since all the raw materials can be put into the kneading extruder at once and kneaded, the production efficiency can be improved.

As the kneading extruder, a commonly used device such as a Henschel mixer, a Banbury mixer, a single screw extruder, a multi-screw extruder, a co-kneader or the like is used. The heating temperature during kneading should be the temperature at which the thermoplastic resin used melts. For example, the thermoplastic resin is about 170° C. to 180° C. when polyethylene is used, about 180° C. to 190° C. when polypropylene is used, and about 200° C. to 210° C. when polylactic acid is used. The screw rotation speed when using a single-screw extruder or a multi-screw extruder is not particularly limited, and is generally used rotation speed. degree.

Next, the moisture vaporization process will be described.

In the above heating and kneading step, the water content in the cellulose nanofiber aqueous dispersion is gradually vaporized. Normally, in an aqueous dispersion of cellulose nanofibers, the cellulose nanofibers aggregate together as the water content decreases. It brings about a compatibilizing effect between the resin and the hydrophilic cellulose nanofibers. Therefore, the cellulose nanofibers are extruded from the extrusion port while being uniformly dispersed in the thermoplastic resin without agglomeration. Moisture vaporized during heat kneading is discharged from the vent of the kneading extruder.

The thermoplastic resin, the aqueous dispersion of cellulose nanofibers, the ethylene copolymer, and the volatile substance are heated and kneaded inside the kneading extruder, extruded from the extrusion port, and cooled and solidified. A thermoplastic composite resin having sustained release properties of volatile substances is obtained. The cooling method is not particularly limited, and a general method can be used. For example, by discharging the discharge into water, the discharge can be cooled easily and inexpensively. The thermoplastic composite resin obtained by the above method can be made into pellets, sheets, powders, fibers, etc. by a known molding method.

EXAMPLES Next, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

<Example>
300 g of polyethylene as a thermoplastic resin, 4 g of an aqueous dispersion of cellulose nanofibers (Daiichi Kogyo Seiyaku Co., Ltd., Rheocrysta (registered trademark)), 30 g of ethylene-methyl methacrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd.), and volatile substances Three grams of rosewood essential oil (manufactured by Essence-Organic Pty. Ltd.) were premixed. Since the solid content of cellulose nanofibers in the aqueous dispersion of cellulose nanofibers is about 2% by mass, the solid content of cellulose nanofibers is 0.08 g.

A mixture of polyethylene, cellulose nanofiber aqueous dispersion, ethylene-methyl methacrylate copolymer and rosewood essential oil is put into the raw material inlet of a multi-screw extruder (manufactured by Toyo Seiki Co., Ltd., trade name "Laboplastomill"). After that, heat kneading was performed at a heating temperature of 180° C. to 190° C. and a screw rotation speed of 15 rpm. During heat kneading, water contained in the aqueous dispersion of cellulose nanofibers is vaporized and discharged from a vent, a raw material inlet, or the like. After visually confirming the presence or absence of aggregates of cellulose nanofibers in the thermoplastic composite resin melt discharged after heat kneading, the thermoplastic composite resin melt was cooled and cooled in a strand bath (manufactured by Toyo Seiki Co., Ltd.). Solidified to obtain a thermoplastic composite resin.

<Comparative example>
A mixture of 300 g of polyethylene as a thermoplastic resin and 3 g of rosewood essential oil (manufactured by Essence-Organic Pty. Ltd.) as a volatile substance was used. A thermoplastic composite resin was obtained in the same manner as in Example 1 except that the aqueous dispersion of cellulose nanofibers and the ethylene-methyl methacrylate copolymer were removed from Example 1.

<Quantitative analysis of volatile substances in resin>
Volatile substances in the resins of Examples and Comparative Examples were quantitatively analyzed by GC/MS measurement. As for the analysis method, the pelletized resin was dissolved using a good solvent for the resin. A poor solvent for the resin was used to reprecipitate and filter the resin component of the resulting solution, and the filtrate was used as a test solution. The test solution was subjected to GC/MS measurement to quantify the volatile substances in the sample. In this analysis, 3 g of added rosewood essential oil (manufactured by Essence-Organic Pty. Ltd.) was used as a quantitative standard, and linalool in rosewood essential oil was used as an index for quantitative analysis.

Table 1 summarizes the quantitative analysis results of the volatile substance linanol using the examples and comparative examples.

From Table 1, although about 70% of the volatile substances remained in the example, only about 55% of the volatile substances remained in the comparative example. As described above, it was found that a large amount of volatile substances remained in the thermoplastic composite resin of the present invention.

<Sustained release test>
A sustained release test of the thermoplastic composite resin of the present invention was conducted. The odors of volatile substances emitted from Examples and Comparative Examples were measured using a portable odor monitor (manufactured by MK Scientific Co., Ltd., GT300-VOC). Table 2 summarizes the measurement results after the date of manufacture, 1 day, 1 week, 2 weeks, and 1 month.

From Table 2, the rate of volatilization of volatile substances is slower in Examples than in Comparative Examples, and three months after production, most of the volatile substances in Comparative Examples have volatilized. In the examples, most of the volatile substances remained and humans could smell the volatile substances. As described above, it was found that the thermoplastic composite resin of the present invention has sustained release properties.

Claims (4)

A thermoplastic composite resin containing a thermoplastic resin, cellulose nanofibers, an ethylene-based copolymer, and a volatile substance,
The thermoplastic resin is one or more selected from among polyethylene, polypropylene, polystyrene, polylactic acid, ABS resin, vinyl chloride resin, and elastomer resin,
The ethylene-based copolymer is an ethylene-methyl methacrylate copolymerorEthylene-methyl acrylate copolymerofis at least one
having sustained release of the volatile substance,
Thermoplastic composite resin. Each glucose on the surface of the cellulose nanofiber has almost all secondary hydroxyl groups,
The thermoplastic composite resin according to claim 1. The cellulose nanofibers are uniformly dispersed in the thermoplastic composite resin,
The thermoplastic composite resin according to claim 1 or 2. At least one selected from polyethylene, polypropylene, polystyrene, polylactic acid, ABS resin, vinyl chloride resin, and elastomeric resin Thermoplastic resin, aqueous dispersion of cellulose nanofibers, and ethylene-methyl methacrylate copolymerorEthylene-methyl acrylate copolymerofat least oneofa heating/kneading step of heating and kneading the ethylene-based copolymer and the volatile component at the melting temperature of the thermoplastic resin;
a water vaporization step of vaporizing water contained in the aqueous dispersion of cellulose nanofibers during the heat kneading;
The method for producing a thermoplastic composite resin according to any one of claims 1 to 3, comprising: