JP2023096626A - Resin composition and method for producing the same, and method for improving strength of resin composition - Google Patents

Abstract

To provide a method for producing a resin composition which has enhanced strength and is blended with a plant-derived fiber, and a method for producing a resin composition which can eliminate a step of evaporating moisture of a plant-derived fiber.SOLUTION: A resin composition contains a plant extract residue, a plant-derived fiber, and a thermoplastic resin. A method for producing a resin composition includes mixing a plant extract residue, a plant-derived fiber, and a thermoplastic resin, drying an obtained mixture, molding the dried matter, and obtaining a molding, in which the plant extract residue is preferably in a hydrous state.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a high-strength resin composition obtained by blending plant extraction residues, and a method for producing the same.

Resin compositions (plastics) have the advantage of being easy to mold, but have the disadvantage of being brittle in terms of strength. Therefore, in order to improve the mechanical strength of the resin composition, cellulose fibers such as cellulose nanofibers are blended into the resin.

For example, Patent Literature 1 below discloses a resin molded body made of a cellulose fiber-dispersed resin composite material in which cellulose fibers are dispersed in a resin and having a thickness of 0.1 mm or more, which contains the cellulose fibers. The amount is 1% by mass or more and less than 70% by mass, and the length-weighted average fiber length of the cellulose fibers measured under predetermined measurement conditions is LL, and the number average fiber length is LN. An invention of a resin molded article that satisfies the formula is disclosed, and this resin molded article can realize excellent mechanical properties while having a thin portion.

In addition, Patent Document 2 below discloses an invention of nanoized cellulose fibers obtained by defibrating a cellulose fiber-containing material derived from a plant body or a microorganism so as to have an average fiber diameter of 4 to 3000 nm. It is disclosed that nano-cellulose fibers are contained in a resin and the composition is molded to form a resin-containing molding.

JP 2020-193263 A JP 2020-116817 A

Cellulose nanofibers are produced by pulverizing plant-derived fibers such as pulp in water, but since they contain a large amount of water (more than 95% by weight), it is necessary to evaporate the water before adding it to the resin. There is a manufacturing burden.
If you try to pulverize the plant-derived fibers in molten resin in order to eliminate the problem of water evaporation, the plant-derived fibers will get entangled with each other, and the resin will be adsorbed there, resulting in the formation of foreign substances in the form of flakes. there were.

Accordingly, an object of the present invention is to provide a resin composition having increased strength, and furthermore, in a method for producing a resin composition containing plant-derived fibers, the step of evaporating water from the plant-derived fibers is eliminated. An object of the present invention is to provide a method for producing a resin composition capable of

A method for producing a resin composition according to one embodiment of the present invention includes mixing a plant extraction residue, plant-derived fibers, and a thermoplastic resin, drying the resulting mixture, and molding the dried product to obtain a molded product. is characterized by obtaining

In the above embodiment, it is preferable to dry while mixing each component, and the mixing of each component is 2 to 20% by mass of the plant extraction residue, 5 to 20% by mass of the plant-derived fiber, and 60 to 60% of the thermoplastic resin. It is preferable to use a blending ratio of 93% by mass.

In the above embodiment, the plant extraction residue is preferably in a water-containing state, specifically, the water content is preferably 50 to 85% by mass.

In the above embodiment, the plant extraction residue preferably contains starch, and specifically, the starch content is preferably 2 to 50% by mass.

In the above embodiment, the plant extraction residue is preferably green tea lees or barley tea lees.

In the above embodiment, the plant-derived fiber is preferably an insoluble dietary fiber, specifically one or more selected from the group consisting of cellulose, hemicellulose, lignin, chitin and chitosan.

In the above embodiment, the water content of the plant-derived fibers is preferably 20% by mass or less.

In the above embodiment, the thermoplastic resin is preferably a resin that can be molded at 230° C. or lower. Specifically, polystyrene resin, ABS resin, polyethylene resin, EVA resin, polypropylene resin, polyvinyl chloride resin, PVA resin, It is preferably one or more selected from the group consisting of PBAT resin, PBS resin, PLA resin, PHBH resin, PHA resin and thermoplastic elastomer.

The above embodiment preferably further contains a dispersion improver.

The present invention is directed to a resin composition containing a plant extraction residue, a plant-derived fiber, and a thermoplastic resin.

The present invention improves the strength of a resin composition by mixing a plant extraction residue, a plant-derived fiber, and a thermoplastic resin, drying the resulting mixture, and molding the dried product to obtain a molded product. can be achieved.

Hereinafter, a resin composition (hereinafter referred to as the present resin composition) as one embodiment of the present invention will be described. However, the present invention is not limited to this embodiment.

The present resin composition contains a plant extraction residue, a plant-derived fiber, and a thermoplastic resin.

(Plant extraction residue)
The plant extraction residue is a residue obtained by extracting or squeezing the leaves or stems of a plant using water, alcohol, or the like as a solvent, and it is preferable to use the extraction residue that is discarded when producing beverages and the like. More specifically, for example, tea leaf residue (so-called tea leaves) such as green tea, oolong tea, and black tea, coffee bean residue (so-called coffee grounds) such as coffee, barley residue such as barley tea (so-called barley tea), and brown rice such as brown rice tea. Residue (so-called brown rice tea lees), buckwheat residue such as buckwheat tea, malt residue such as beer (so-called beer lees), apple lees, potato lees, grape lees, and the like.

The plant extraction residue is preferably in a hydrated state containing water. Specifically, the water content is preferably 50 to 85% by mass, particularly 60 to 85% by mass, further preferably 65 to 80% by mass. Extraction residues discarded in the production of beverages often contain a large amount of water, such as a water content of 85% by mass or more, so it is preferable to reduce the content to the above range by hot air drying or dehydration. By adjusting the moisture content of the plant extraction residue in advance, in the production method described later, the production is facilitated, the production time can be shortened, the plant extraction residue is easy to store and handle, and the quality of the molded product is uniform. There are advantages such as becoming
In addition, the plant extraction residue preferably contains starch, and the starch content is preferably 2 to 50% by weight, particularly 4 to 45% by weight, more preferably 10 to 40% by weight, in terms of dry solid content. The starch content in the resin composition is preferably 0.2 to 15 mass %, particularly 0.5 to 10 mass %, more preferably 1 to 5 mass % in terms of dry solid content.
In addition, starch refers to polysaccharides, for example, those having 10 or more sugars.
The starch content can be adjusted, for example, by adding starch or changing the type/part of the plant extraction residue. Also, the starch content can be measured by a known method, for example, by an enzymatic method. A sample is treated with α-amylase and glucoamylase to decompose it into glucose for quantification.

From the viewpoint of moisture content and starch content, the starch-containing plant extraction residue is preferably barley tea husks, brown rice husks, buckwheat lees, beer lees, and potato lees.

(Plant-derived fiber)
Plant-derived fibers are fibers derived from plants contained in plants such as vegetables and trees. contained in plants, etc.
The plant-derived fiber is preferably insoluble dietary fiber, and the insoluble dietary fiber includes wood, straw, bamboo, hemp, etc., and pulp or regenerated pulp obtained therefrom.
More specifically, the insoluble dietary fiber includes cellulose, hemicellulose, lignin, chitin, chitosan, and the like, and one or two or more selected from these are preferred.

The plant-derived fiber preferably has a low water content. Specifically, the water content is preferably 20% by mass or less, particularly 19% by mass or less, and more preferably 18% by mass or less. Although the lower limit is not particularly limited, it is preferably 5% by mass or more. Also, the difference in water content between the plant extraction residue and the plant-derived fiber is preferably 30 to 90% by mass, particularly 40 to 85% by mass, more preferably 45 to 80% by mass.

(Thermoplastic resin)
A thermoplastic resin is a resin that can be melted and molded by applying heat. For example, it is preferably a resin that can be molded at 230° C. or lower, particularly 220° C. or lower, and more preferably 210° C. or lower. Specific examples include polystyrene resins, ABS resins, polyethylene resins, EVA resins, polypropylene resins, polyvinyl chloride resins, PVA resins, PBAT resins, PBS resins, PLA resins, PHBH resins, PHA resins, thermoplastic elastomers, etc. One or more selected from these is preferred.

(other ingredients)
In the present resin composition, components other than plant extraction residues, plant-derived fibers, and thermoplastic resins may be arbitrarily blended. One or more of additives such as stabilizers, ultraviolet absorbers, curing agents, cross-linking agents, lubricants and antistatic agents may be blended. Coloring agents such as dyes and pigments may also be blended.

The blending ratio of these is not particularly limited, and can be blended as appropriate depending on the application.
The dispersion improver here improves the dispersibility of the plant extraction residue and the plant-derived fiber in the thermoplastic resin and increases the strength of the resin. For example, titanium dioxide, calcium carbonate, etc. can be used.

(mixing ratio)
The blending ratio of each component is preferably 2 to 20% by mass of plant extraction residue, 5 to 20% by mass of plant-derived fiber, and 60 to 93% by mass of thermoplastic resin in an absolute dry state. 15% by mass, 6-17% by mass of plant-derived fiber, and 65-92% by mass of thermoplastic resin, more preferably, 2-10% by mass of plant extraction residue, 7-15% by mass of plant-derived fiber, thermoplastic It is particularly preferable to use a proportion of 70 to 91% by weight of the resin.

<Method for producing resin composition>
A method for producing a resin composition (hereinafter referred to as the present production method) comprises mixing a plant extraction residue, a plant-derived fiber, and a thermoplastic resin, drying the resulting mixture, and molding the dried product. A manufacturing method characterized by obtaining a molding.

(Mixing process)
In this production method, first, the above components are mixed to obtain a mixture.
This mixing may be carried out by blending the plant extraction residue, the plant-derived fiber, the thermoplastic resin, and other components in appropriate proportions as necessary, and is not particularly limited, but may be carried out by a mechanical kneading method. can. For example, a single-screw extruder, a twin-screw extruder, a Henschel mixer, a Banbury mixer, a kneader mixer, a Brabender, a calender roll, or the like can be used. It is preferable to perform the mixing while pulverizing each component.

A suitable blending ratio of each component in this mixing is the same as the blending ratio of the present resin composition described above.

(Drying process)
The mixture is then dried to obtain a dry product.
This drying can evaporate water from the mixture, and it is preferable to perform the drying while the mixture is being mixed, that is, to perform the mixing step and the drying step at the same time.
For drying while mixing, for example, using a Banbury mixer, the inside of the mixer is set to 100° C. or higher, preferably in the range of 100 to 180° C., and the mixer is operated to dry while pulverizing each component. , will be mixed.
After drying, the dried product is kneaded into a clayey, ie, sticky, moisture content of preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1% by mass or less. .

(Molding process)
Finally, the clay is molded.
For example, the clay can be put into an extruder, kneaded and extruded in the form of a wire through a nozzle, and cut into appropriate lengths to form pellets.
In addition, known methods can be used for molding, for example, extrusion molding, injection molding, blow molding, press molding, calender molding, T-die molding, inflation molding, compression molding, pipe extrusion molding, and vacuum molding. It can be carried out. For these moldings, the clay itself, crushed clay, or pellets may be used.

(Application)
Since the present resin composition contains plant extraction residues, plant-derived fibers, and a thermoplastic resin, it becomes a high-strength resin with increased strength, and can be suitably used for applications requiring strength. Furthermore, if the plant extraction residue contains starch, the strength will be further enhanced due to the effect of the starch.
In this production method, if the plant extraction residue is in a water-containing state, when mixing with the plant-derived fibers and the thermoplastic resin, the water contained in the plant-extraction residue moderately loosens the plant-derived fibers. Since the plant-derived fibers do not need to be pulverized in water in advance and the manufacturing process for pulverizing in water can be eliminated, the manufacturing process is simplified.

The present resin composition can be molded, for example, into pellets, which are then melted and poured into a mold to form a resin molding.
The resin molding can be suitably used, for example, as a transportation material, as a construction/furniture material, as a housing, and the like.
Examples of transportation material applications include transportation materials such as pallets, containers, trolleys, and trays.
Construction/furniture material applications include, for example, interior/exterior wall materials, roofing materials, tiles, residential building materials such as doors, and furniture such as desks and chairs. Examples of housing applications include housings for electric products such as electronic devices and home appliances, and containers and packaging materials for foodstuffs and miscellaneous goods.

In this specification, when expressed as "X to Y" (where X and Y are arbitrary numbers), unless otherwise specified, it means "X or more and Y or less", and "preferably larger than X" and " preferably less than Y".

Examples of the present invention will be described below. However, the present invention is not limited to this example.

(Strength evaluation test)
Each of the following components was blended in appropriate proportions shown in Table 1, and resin compositions of Examples 1 to 4 and Comparative Examples 1 and 2 were produced by the following production method.

<Plant extraction residue>
As the plant extraction residue, barley tea husks, which are the extraction residue in the production of the trade name “Kenko Mineral Barley Tea” (manufactured by Itoen Co., Ltd.), were used. The moisture content of this barley tea husk was 75% by mass, and the starch content was 30% by mass in terms of dry solid content. The moisture content was measured with an infrared moisture meter (Ketto Kagaku Kenkyusho Co., Ltd.), and the starch content was measured with a total starch analysis kit (AA/AMG) (manufactured by Megazyme).

<Plant-derived fiber>
As the plant-derived fiber, a pulp pulverized material obtained by pulverizing pulp (manufactured by PT TEL Co., Ltd.) with a mixer to a size of 7 mm or less was used. The moisture content of this pulp was 7.5% by mass. The moisture content was measured with an infrared moisture meter (Ketto Science Laboratory Co., Ltd.).

<Thermoplastic resin>
A polypropylene resin (manufactured by SunAllomer Co., Ltd.) was used as the thermoplastic resin.

<Manufacturing method>
The plant extraction residue, plant-derived resin and thermoplastic resin are adjusted to the blending ratio shown in Table 1, and this is put into a kneader mixer (manufactured by Toshin Co., Ltd.) whose interior is set to 120 ° C., and pulverized and dried while mixing. After that, the thermoplastic resin was melted by the heat generated during mixing and kneaded into a mochi.
The kneaded material was put into a hopper of a twin-screw extruder, extruded into a wire shape from a nozzle while kneading, and cut to produce a resin composition in the form of pellets.
This resin composition was melted at 180° C. and poured into a mold to prepare a dumbbell-shaped test piece.
In addition, Comparative Example 1 could not be molded.

<Bending elastic modulus measurement>
Using test pieces of the resin compositions of Examples 1 to 4 and Comparative Example 2, the flexural modulus was measured according to JISK7171.
The strength was evaluated according to the following five-level index from the measurement results of the flexural modulus. Table 1 shows the results. Incidentally, Reference Example 1 shows the flexural modulus when only the thermoplastic resin is used.
1: Flexural modulus of 929 or less, or not measurable 2: Flexural modulus of 930 to 939
3: Flexural modulus is 940 to 949
4: Flexural modulus is 950 to 959
5: Flexural modulus is 960 or more

(Results of strength evaluation test)
From the results of the strength evaluation test, it was found that Examples 1 to 4 were good with a strength evaluation of 3 or more. They have a blending ratio of plant extraction residue of 2 to 20% by mass and a blending ratio of plant-derived fiber of 5 to 20% by mass. In the strength evaluation test, Examples 2 and 3 were highly evaluated.

(Comprehensive evaluation test)
Fixing the blending ratio of each component in Example 2, changing the water content, the starch content in the resin composition, and the type of plant extraction residue to prepare Examples 5 to 15, and comprehensively evaluate the resin composition did the test.

(Moisture content change)
Examples 5 to 9 were produced by changing the moisture content of the barley used in Example 2 to the ratio shown in Table 2. The moisture content of barley tea leaves was measured with an infrared moisture meter (Ketto Kagaku Kenkyusho Co., Ltd.), and the moisture content was changed by evaporating the moisture with a hot air dryer.

(Change in starch ratio)
Examples 10 to 13 were produced by changing the starch ratio of the used barley tea husks used in Example 2 so that the ratio of starch in the resin composition was as shown in Table 2. The starch content of barley tea husks was measured using a total starch analysis kit (AA/AMG) (manufactured by Megazyme). In addition, the proportion of starch was changed by changing the part of barley tea husks and adding "starch, derived from corn" (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

(Plant extraction residue change)
Examples 14 and 15 were prepared by changing the barley tea leaves used in Example 2 to green tea leaves, which are extraction residues in the production of the trade name "Oi Ocha Green Tea" (manufactured by Itoen Co., Ltd.). The water content of this green tea husk was 75% by mass. Table 2 shows the ratio of starch in the resin composition. The starch content was changed by adding "starch, derived from corn" (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

(comprehensive evaluation)
As a comprehensive evaluation of Examples 5 to 15, "moldability", "uniformity of resin composition", and "light resistance (color loss)" were evaluated.

<Moldability>
Moldability was evaluated according to the following indices by pouring the resin composition into a 5 mm-thick plate-like mold and visually confirming the number of lumps formed in a piece cut into a 10 cm square.
1: Much worse than Reference Example 1 (10 or more)
2: Worse than Reference Example 1 (5 to 9 pieces)
3: Slightly worse than Reference Example 1 (1 to 4 pieces)
4: Equivalent to or better than Reference Example 1 (no lumps formed)

<Uniformity of Resin Composition>
For the uniformity of the resin composition, the resin composition was poured into a flat mold with a thickness of 5 mm, and the number of unevenness generated in a piece cut into a 10 cm square was visually confirmed, and the following indices were used to evaluate the uniformity of the resin composition.
1: Much worse than Reference Example 1 (10 or more)
2: Worse than Reference Example 1 (5 to 9 pieces)
3: Slightly worse than Reference Example 1 (1 to 4 pieces)
4: Equivalent or better than Reference Example 1 (unevenness is not formed)

<Light fastness (color loss)>
The light fastness (color loss) was visually evaluated by the following indices after storage for 14 days under continuous irradiation at 10,000 lux.
1: The color has come off significantly compared to immediately after production 2: The color has come off compared to immediately after production 3: The color has come off a little compared to immediately after production 4: The same color as immediately after production or the color has come off not

(Results of Comprehensive Evaluation Test)
The score for the strength was added to the scores for the evaluation results of the moldability, the uniformity of the resin composition, and the light resistance, and the total was calculated.
Examples 5 to 15 all have strength and are not problematic in practice, but Example 5 with a low water content or Example 9 with a high water content is inferior in moldability to others. rice field. From this point of view, it can be said that the water content of the plant extraction residue is preferably 50 to 85% by mass.
Further, Example 10 with a low starch content and Example 13 with a high starch content were inferior in uniformity of the resin composition. From this point of view, it can be said that the starch content in the resin composition is preferably 0.2 to 15% by mass.
Examples 14 and 15 using green tea leaves were inferior in light resistance to barley tea leaves.

(Addition of dispersion improver)
The blending ratio of the thermoplastic resin in Example 2 was changed to 75% by mass, and calcium carbonate (manufactured by Calfine Co., Ltd.) as a dispersion improver was added to 10% by mass.

(Result of addition of dispersion improver)
As a result of changing the mixing ratio of the resin and adding the dispersion improver, the strength was 960 or more, and the strength was good even when the dispersion improver was added.

Claims (16)

A method for producing a resin composition, comprising mixing a plant extract residue, a plant-derived fiber, and a thermoplastic resin, drying the resulting mixture, and molding the dried product to obtain a molded product. The method for producing a resin composition according to claim 1, wherein the drying is performed while the mixing is performed. The resin composition according to claim 1 or 2, wherein the mixing is performed by blending 2 to 20% by mass of the plant extraction residue, 5 to 20% by mass of the plant-derived fiber, and 60 to 93% by mass of the thermoplastic resin. Production method. 4. The method for producing a resin composition according to any one of claims 1 to 3, wherein the plant extraction residue is in a water-containing state. 5. The method for producing a resin composition according to claim 4, wherein the water content of the plant extraction residue is 50 to 85% by mass. The method for producing a resin composition according to any one of claims 1 to 5, wherein the plant extraction residue contains starch. 7. The production method according to claim 6, wherein the starch content of the plant extraction residue is 2 to 50% by mass in terms of dry solid content. The method for producing a resin composition according to any one of claims 1 to 7, wherein the plant extraction residue is green tea husks or barley tea husks. The method for producing a resin composition according to any one of claims 1 to 8, wherein the plant-derived fiber is insoluble dietary fiber. 10. The method for producing a resin composition according to claim 9, wherein said insoluble dietary fiber is one or more selected from the group consisting of cellulose, hemicellulose, lignin, chitin and chitosan. The method for producing a resin composition according to any one of claims 1 to 10, wherein the plant-derived fiber has a water content of 20% by mass or less. The method for producing a resin composition according to any one of claims 1 to 11, wherein the thermoplastic resin is a resin that can be molded at 230°C or lower. The thermoplastic resin is a group consisting of polystyrene resin, ABS resin, polyethylene resin, EVA resin, polypropylene resin, polyvinyl chloride resin, PVA resin, PBAT resin, PBS resin, PLA resin, PHBH resin, PHA resin and thermoplastic elastomer. The method for producing a resin composition according to claim 12, which is one or more selected from. 14. The method for producing a resin composition according to any one of claims 1 to 13, further comprising a dispersion improver. A resin composition containing a plant extraction residue, a plant-derived fiber, and a thermoplastic resin. A method for improving the strength of a resin composition, comprising mixing a plant extract residue, a plant-derived fiber, and a thermoplastic resin, drying the resulting mixture, and molding the dried product to obtain a molded product.